Medical Calculator

Free WHO z-scores for child growth and 500 clinical formulas and scores across 20 specialties, each with its interpretation. Search by name, abbreviation or formula, or pick a specialty. Press / to search.
500 calculators
Renal & Electrolytes

Creatinine Clearance (Cockcroft-Gault)

Estimates kidney function from age, weight and creatinine; still the standard for adjusting many drug doses. CrCl = [(140 − age) × weight(kg)] / (72 × SCr mg/dL); × 0.85 if female
Renal & Electrolytes

eGFR (CKD-EPI 2021, race-free)

The recommended race-free equation for estimating GFR and staging chronic kidney disease in adults. eGFR = 142 × min(SCr/κ,1)^α × max(SCr/κ,1)^−1.200 × 0.9938^age × 1.012 [if female]; κ=0.7 F/0.9 M; α=−0.241 F/−0.302 M
Renal & Electrolytes

eGFR (MDRD 4-variable)

Older GFR equation, still printed by some labs; underestimates GFR when kidney function is near normal. eGFR = 175 × SCr^−1.154 × age^−0.203 × 0.742 [if female]
Renal & Electrolytes

eGFR Cystatin C (CKD-EPI 2012)

Estimates GFR from cystatin C, which is less affected by muscle mass, diet or amputation than creatinine. eGFR = 133 × min(CysC/0.8,1)^−0.499 × max(CysC/0.8,1)^−1.328 × 0.996^age × 0.932 [if female]
Renal & Electrolytes

Bedside Schwartz (pediatric eGFR)

Estimates GFR in children from height and creatinine; used to detect and stage paediatric CKD. eGFR = 0.413 × height(cm) / SCr(mg/dL)
Renal & Electrolytes

Measured Creatinine Clearance (24-h urine)

Measures creatinine clearance directly from a timed urine collection when equations are unreliable. CrCl = (Urine Cr × Urine volume) / (Plasma Cr × time in min)
Renal & Electrolytes

Fractional Excretion of Sodium (FENa)

Helps separate prerenal acute kidney injury from tubular injury (ATN) in oliguric patients. FENa = (UNa × PCr) / (PNa × UCr) × 100
Renal & Electrolytes

Fractional Excretion of Urea (FEUrea)

An alternative to FENa when the patient has received diuretics, which make FENa unreliable. FEUrea = (UUrea × PCr) / (PUrea × UCr) × 100
Renal & Electrolytes

Fractional Excretion of Potassium

Shows how much filtered potassium the kidneys excrete; helps work up hyper- or hypokalaemia. FEK = (UK × PCr) / (PK × UCr) × 100
Renal & Electrolytes

Fractional Excretion of Phosphate

Tells whether low phosphate is due to renal wasting or to poor intake / shifts. FEPO4 = (UPO4 × PCr) / (PPO4 × UCr) × 100
Renal & Electrolytes

BUN:Creatinine Ratio

Points toward the cause of a raised urea: prerenal states and GI bleeding raise the ratio. Ratio = BUN (mg/dL) / SCr (mg/dL)
Renal & Electrolytes

Urine Protein:Creatinine Ratio (UPCR)

Quantifies proteinuria from a spot urine sample instead of a 24-hour collection. UPCR = Urine protein (mg/dL) / Urine Cr (mg/dL)
Renal & Electrolytes

Urine Albumin:Creatinine Ratio (UACR)

Screens for albuminuria and defines the A1–A3 albuminuria categories of CKD. UACR = Urine albumin (mg) / Urine Cr (g)
Renal & Electrolytes

Free Water Clearance

Shows whether the kidneys are excreting or retaining free water. CH2O = V × (1 − Uosm/Posm)
Renal & Electrolytes

Electrolyte-Free Water Clearance

Better than classic free water clearance for predicting where serum sodium is heading. CeH2O = V × [1 − (UNa + UK)/PNa]
Renal & Electrolytes

Urine Anion Gap

Separates GI bicarbonate loss from renal tubular acidosis in a normal-anion-gap acidosis. UAG = (UNa + UK) − UCl
Renal & Electrolytes

Transtubular Potassium Gradient (TTKG)

Estimates potassium secretion in the distal nephron; reflects aldosterone activity. TTKG = (UK × Posm) / (PK × Uosm)
Renal & Electrolytes

Urine K:Creatinine Ratio

Spot-urine test to tell renal from extrarenal potassium loss in hypokalaemia. UK (mmol/L) / UCr (mmol/L)
Renal & Electrolytes

Calculated Serum Osmolality

Estimates serum osmolality from sodium, glucose and urea. Osm = 2×Na + Glucose/18 + BUN/2.8 (mg/dL); SI: 2Na + Glucose + Urea (mmol/L)
Renal & Electrolytes

Osmolal Gap

Difference between measured and calculated osmolality; a raised gap suggests toxic alcohols. OG = Measured Osm − Calculated Osm
Renal & Electrolytes

Effective (Tonic) Osmolality

Osmolality that drives water shifts (excludes urea); used to diagnose hyperosmolar states. Osm eff = 2×Na + Glucose/18
Renal & Electrolytes

Corrected Sodium for Hyperglycemia (Katz)

Corrects sodium for the dilutional effect of high glucose (1.6 factor). Na corr = Na + 1.6 × (Glucose − 100)/100
Renal & Electrolytes

Corrected Sodium (Hillier)

Corrects sodium for hyperglycaemia using the 2.4 factor, more accurate at very high glucose. Na corr = Na + 2.4 × (Glucose − 100)/100
Renal & Electrolytes

Total Body Water (Watson-simplified)

Estimates total body water, the volume used in sodium and water deficit formulas. TBW = weight(kg) × factor; 0.6 adult M, 0.5 adult F, 0.5 elderly M, 0.45 elderly F, 0.6 child, 0.7–0.8 infant
Renal & Electrolytes

Free Water Deficit

Estimates the water needed to correct hypernatraemia. FWD = TBW × (Na/140 − 1)
Renal & Electrolytes

Sodium Deficit

Estimates the sodium needed to raise serum sodium to a target in hyponatraemia. Na deficit = TBW × (desired Na − current Na)
Renal & Electrolytes

Adrogue–Madias: Change in Na per 1 L Infusate

Predicts how much one litre of a chosen fluid will change serum sodium. ΔNa = (Infusate Na + K − Serum Na) / (TBW + 1)
Renal & Electrolytes

Hypertonic Saline Bolus (Hyponatremia)

Emergency hypertonic saline dosing for severe symptomatic hyponatraemia. 3% NaCl 100–150 mL IV over 10–20 min (adult); 2 mL/kg pediatric (repeat ×2–3 PRN)
Renal & Electrolytes

Corrected Calcium for Albumin (Payne)

Corrects total calcium for low albumin to estimate the physiologically active level. Ca corr = Ca + 0.8 × (4.0 − albumin g/dL)
Renal & Electrolytes

Calcium × Phosphate Product

Product of calcium and phosphate; high values raise the risk of soft-tissue calcification in CKD. Ca (mg/dL) × PO4 (mg/dL)
Renal & Electrolytes

Potassium Deficit (approximate)

Rough estimate of total-body potassium deficit from the serum level. Each 0.3 mmol/L drop in K ≈ 100 mmol total body deficit (K 3.0–3.5 ≈ 200–400 mmol)
Renal & Electrolytes

Bicarbonate Deficit

Estimates the bicarbonate needed to partly correct a severe metabolic acidosis. HCO3 deficit = 0.5 × weight(kg) × (desired HCO3 − measured HCO3)
Renal & Electrolytes

Kt/V (Daugirdas second generation)

Measures delivered haemodialysis dose from pre/post urea, time and ultrafiltration. Kt/V = −ln(R − 0.008t) + (4 − 3.5R) × UF/W; R = post/pre BUN, t hours, UF L, W kg
Renal & Electrolytes

Urea Reduction Ratio (URR)

Simple measure of haemodialysis adequacy from the fall in urea. URR = (pre BUN − post BUN) / pre BUN × 100
Renal & Electrolytes

Dialysis Ultrafiltration Rate

Rate of fluid removal during dialysis; high rates cause hypotension and harm. UFR = Fluid removed (mL) / [dry weight (kg) × duration (h)]
Renal & Electrolytes

CRRT Effluent Dose

Delivered dose of continuous renal replacement therapy per kg. Dose = (Dialysate + Replacement + Net UF rate) / weight
Renal & Electrolytes

Urine Output Rate

Urine output per kg per hour; the urine criterion for acute kidney injury. UO = Urine volume (mL) / [weight (kg) × hours]
Renal & Electrolytes

KDIGO AKI Staging (creatinine)

Stages acute kidney injury by rise in creatinine (and need for dialysis). Stage by SCr ratio to baseline: 1 = 1.5–1.9× or ↑≥0.3 mg/dL in 48 h; 2 = 2–2.9×; 3 = ≥3× or ≥4.0 mg/dL or RRT
Acid–Base

Serum Anion Gap

Screens metabolic acidosis for unmeasured anions (lactate, ketones, toxins, uraemia). AG = Na − (Cl + HCO3)
Acid–Base

Albumin-Corrected Anion Gap

Corrects the anion gap for low albumin, which otherwise hides a high-gap acidosis. AG corr = AG + 2.5 × (4.0 − albumin g/dL)
Acid–Base

Delta Gap

Compares the rise in anion gap with the fall in bicarbonate to detect a second disorder. ΔAG = AG − 12
Acid–Base

Delta Ratio

Ratio form of the delta gap; classifies mixed metabolic acid–base disorders. Δ/Δ = (AG − 12) / (24 − HCO3)
Acid–Base

Winter's Formula (expected PaCO2)

Predicts the expected PaCO2 in metabolic acidosis to check respiratory compensation. Expected PaCO2 = 1.5 × HCO3 + 8 ± 2
Acid–Base

Expected PaCO2 in Metabolic Alkalosis

Predicts the expected PaCO2 in metabolic alkalosis. PaCO2 = 0.7 × HCO3 + 21 ± 2 (or 40 + 0.7 × ΔHCO3)
Acid–Base

Acute Respiratory Acidosis Compensation

Expected bicarbonate rise in acute respiratory acidosis. ΔHCO3 = 0.1 × ΔPaCO2 (↑1 per 10 mmHg)
Acid–Base

Chronic Respiratory Acidosis Compensation

Expected bicarbonate rise in chronic (renally compensated) respiratory acidosis. ΔHCO3 = 0.35 × ΔPaCO2 (↑3.5–4 per 10 mmHg)
Acid–Base

Acute Respiratory Alkalosis Compensation

Expected bicarbonate fall in acute respiratory alkalosis. ΔHCO3 = −0.2 × ΔPaCO2 (↓2 per 10 mmHg)
Acid–Base

Chronic Respiratory Alkalosis Compensation

Expected bicarbonate fall in chronic respiratory alkalosis. ΔHCO3 = −0.4 to −0.5 × ΔPaCO2 (↓4–5 per 10 mmHg)
Acid–Base

Henderson–Hasselbalch

Calculates pH from bicarbonate and PaCO2; checks a blood gas for internal consistency. pH = 6.1 + log10[HCO3 / (0.03 × PaCO2)]
Acid–Base

Henderson Equation ([H+])

Calculates hydrogen-ion concentration from PaCO2 and bicarbonate. [H+] = 24 × PaCO2 / HCO3
Acid–Base

Apparent Strong Ion Difference (SIDa)

Stewart approach: difference between strong cations and strong anions. SIDa = (Na + K + Ca + Mg) − (Cl + lactate)
Acid–Base

Effective Strong Ion Difference (SIDe)

Stewart approach: buffer base from bicarbonate, albumin and phosphate. SIDe = HCO3 + 2.8×albumin(g/dL)×(0.123×pH − 0.631) + PO4(mmol/L)×(0.309×pH − 0.469)
Acid–Base

Strong Ion Gap (SIG)

Detects unmeasured anions with the Stewart approach (SIDa − SIDe). SIG = SIDa − SIDe
Acid–Base

Base Excess (Van Slyke, standard)

Metabolic component of a blood gas, independent of the respiratory component. SBE = 0.93 × [HCO3 − 24.4 + 14.83 × (pH − 7.4)]
Acid–Base

Lactate Clearance

Fall in lactate over hours of resuscitation; a marker of response in sepsis. LC = (Lactate initial − Lactate at 2–6 h) / Lactate initial × 100
Cardiology

Mean Arterial Pressure (MAP)

Average arterial pressure that perfuses organs; the usual target in shock (≥65 mmHg). MAP = DBP + (SBP − DBP)/3 = (SBP + 2×DBP)/3
Cardiology

Pulse Pressure

Difference between systolic and diastolic pressure; wide in stiff arteries, narrow in low output. PP = SBP − DBP
Cardiology

Shock Index

Heart rate divided by systolic pressure; an early bedside marker of hidden shock. SI = HR / SBP
Cardiology

Modified Shock Index

Heart rate divided by MAP; adds diastolic pressure to the shock index. MSI = HR / MAP
Cardiology

Pediatric Age-Adjusted Shock Index (SIPA)

Shock index adjusted for age in injured children. SI = HR/SBP; abnormal if >1.22 (4–6 y), >1.0 (7–12 y), >0.9 (13–16 y)
Cardiology

Rate Pressure Product (Double Product)

Product of heart rate and systolic pressure; reflects myocardial oxygen demand. RPP = HR × SBP
Cardiology

Cardiac Output (Fick)

Cardiac output from oxygen consumption and arterial–venous oxygen content. CO = VO2 / (CaO2 − CvO2) × 10 (VO2 ≈ 125 mL/min/m² × BSA)
Cardiology

Cardiac Output (HR × SV)

Cardiac output from heart rate and stroke volume. CO = HR × SV / 1000
Cardiology

Cardiac Index

Cardiac output indexed to body size; the preferred way to compare patients. CI = CO / BSA
Cardiology

Stroke Volume

Volume ejected per beat. SV = CO × 1000 / HR (or EDV − ESV)
Cardiology

Stroke Volume Index

Stroke volume indexed to body surface area. SVI = SV / BSA
Cardiology

Ejection Fraction

Percentage of the left-ventricular volume ejected per beat; classifies heart failure. EF = (EDV − ESV) / EDV × 100
Cardiology

Fractional Shortening (echo M-mode)

M-mode measure of LV systolic function from end-diastolic and end-systolic dimensions. FS = (LVEDD − LVESD) / LVEDD × 100
Cardiology

LV Mass (ASE cube/Devereux)

Estimates left-ventricular mass from echo wall thicknesses (Devereux formula). LV mass = 0.8 × 1.04 × [(IVSd + LVIDd + PWd)³ − LVIDd³] + 0.6
Cardiology

Relative Wall Thickness

Wall thickness relative to cavity size; separates concentric from eccentric hypertrophy. RWT = 2 × PWd / LVIDd
Cardiology

Systemic Vascular Resistance (SVR)

Afterload of the systemic circulation; low in vasodilated shock, high in cardiogenic shock. SVR = 80 × (MAP − CVP) / CO
Cardiology

Pulmonary Vascular Resistance (PVR)

Resistance across the lungs; key for diagnosing pre-capillary pulmonary hypertension. PVR = (mPAP − PAWP) / CO
Cardiology

Pulmonary Vascular Resistance Index

Pulmonary vascular resistance indexed to body size (used in children). PVRI = (mPAP − PAWP) / CI
Cardiology

Transpulmonary Gradient

Pressure drop across the pulmonary bed; separates pre- from post-capillary pulmonary hypertension. TPG = mPAP − PAWP
Cardiology

Diastolic Pulmonary Gradient

Diastolic pressure gradient; identifies combined pre- and post-capillary pulmonary hypertension. DPG = PA diastolic − PAWP
Cardiology

Mean Pulmonary Artery Pressure (estimate)

Estimates mean pulmonary artery pressure from systolic pressure. mPAP ≈ 0.61 × sPAP + 2
Cardiology

RVSP from Tricuspid Regurgitation (echo)

Estimates RV systolic pressure from the tricuspid jet on echo; screens for pulmonary hypertension. RVSP = 4 × (TR Vmax)² + RAP
Cardiology

Simplified Bernoulli Pressure Gradient

Converts a Doppler velocity into a pressure gradient across a valve or defect. ΔP = 4 × V² (V in m/s)
Cardiology

Qp:Qs (Shunt Fraction, oximetry)

Pulmonary-to-systemic flow ratio from oximetry; sizes an intracardiac shunt. Qp/Qs = (SaO2 − SvO2[mixed venous]) / (SpvO2 − SpaO2)
Cardiology

Qp:Qs (Doppler)

Pulmonary-to-systemic flow ratio from Doppler echo. Qp/Qs = (RVOT VTI × π × (RVOT d/2)²) / (LVOT VTI × π × (LVOT d/2)²)
Cardiology

Mixed Venous Saturation (Flamm)

Estimates mixed venous saturation from SVC and IVC samples (Flamm). MVO2 = (3 × SVC sat + IVC sat) / 4
Cardiology

Aortic Valve Area (Continuity Equation)

Aortic valve area by the continuity equation; grades aortic stenosis. AVA = (LVOT area × LVOT VTI) / AV VTI; LVOT area = π × (LVOT d/2)²
Cardiology

Gorlin Formula (valve area, cath)

Valve area from catheter pressures and flow (Gorlin). Area = CO / (HR × SEP or DFP × 44.3 × C × √mean gradient); C=1 aortic, 0.85 mitral
Cardiology

Mitral Valve Area (Pressure Half-Time)

Mitral valve area from the pressure half-time on Doppler. MVA = 220 / PHT (ms)
Cardiology

Dimensionless Index (Velocity Ratio)

LVOT-to-valve velocity ratio; grades aortic stenosis independent of LVOT size errors. DI = LVOT VTI / AV VTI
Cardiology

Regurgitant Volume & Fraction (PISA)

Quantifies valve regurgitation using the proximal isovelocity surface area method. EROA = 2πr² × Va / Vmax; RVol = EROA × VTI regurgitant; RF = RVol / total SV × 100
Cardiology

E/e′ Ratio

Echo estimate of left-ventricular filling pressure (diastolic function). E/e′ = mitral E velocity / average mitral annular e′
Cardiology

LA Volume Index

Left-atrial volume indexed to body size; a marker of chronic diastolic dysfunction. LAVI = LA volume (biplane) / BSA
Cardiology

TAPSE

Echo measure of right-ventricular longitudinal systolic function. Longitudinal tricuspid annular displacement (M-mode)
Cardiology

Corrected QT (Bazett)

Corrects QT for heart rate (Bazett); overcorrects at fast heart rates. QTc = QT / √RR (s)
Cardiology

Corrected QT (Fridericia)

Corrects QT for heart rate (Fridericia); more accurate than Bazett at fast or slow rates. QTc = QT / RR^(1/3)
Cardiology

Heart Rate from ECG

Quick heart rate from the ECG grid. HR = 300 / large squares between R waves = 1500 / small squares
Cardiology

Mean QRS Axis (approximate)

Estimates the frontal-plane QRS axis from leads I and aVF. Axis = arctan[(2 × net aVF) / (√3 × net I)]
Cardiology

Sokolow–Lyon Voltage

ECG voltage criterion for left-ventricular hypertrophy. S V1 + R V5 or V6
Cardiology

Maximum Predicted Heart Rate

Predicted maximal heart rate for exercise testing and training. HRmax = 220 − age (or Tanaka 208 − 0.7 × age)
Cardiology

Target Heart Rate (Karvonen)

Training heart-rate target using heart-rate reserve (Karvonen). THR = [(HRmax − HRrest) × intensity%] + HRrest
Cardiology

Duke Treadmill Score

Prognostic score from a Bruce treadmill test. DTS = Exercise time (min, Bruce) − 5 × ST deviation (mm) − 4 × angina index (0 none,1 non-limiting,2 limiting)
Cardiology

METs from Treadmill

Converts oxygen uptake into metabolic equivalents of exercise capacity. METs = VO2 (mL/kg/min) / 3.5
Cardiology

CHA₂DS₂-VASc Score

Estimates stroke risk in atrial fibrillation to decide on anticoagulation. CHF 1, HTN 1, Age ≥75 2, DM 1, Stroke/TIA 2, Vascular dz 1, Age 65–74 1, Female 1
Cardiology

HAS-BLED Score

Estimates major bleeding risk on anticoagulation; flags modifiable risk factors. HTN, Abnormal renal/liver (1 each), Stroke, Bleeding, Labile INR, Elderly >65, Drugs/alcohol (1 each)
Cardiology

HEART Score (chest pain)

Risk-stratifies chest pain in the emergency department for major adverse cardiac events. History, ECG, Age, Risk factors, Troponin — each 0–2
Cardiology

TIMI Score UA/NSTEMI

Estimates 14-day risk of death, MI or urgent revascularisation in UA/NSTEMI. Age ≥65, ≥3 CAD risk factors, known CAD ≥50%, ASA in 7 d, ≥2 angina in 24 h, ST deviation ≥0.5 mm, +marker (1 each)
Cardiology

TIMI Score STEMI

Estimates 30-day mortality in STEMI. Age 65–74 (2), ≥75 (3), DM/HTN/angina 1, SBP<100 3, HR>100 2, Killip II–IV 2, Wt<67 kg 1, anterior STE/LBBB 1, time >4 h 1
Cardiology

GRACE Score (ACS)

Estimates in-hospital and 6-month mortality in acute coronary syndromes. Age, HR, SBP, creatinine, Killip class, cardiac arrest, ST deviation, elevated enzymes (nomogram)
Cardiology

Killip Classification

Classifies heart failure severity after myocardial infarction by examination. I no HF; II rales/S3; III pulmonary edema; IV cardiogenic shock
Cardiology

Wells Score for DVT

Estimates the clinical probability of deep vein thrombosis before testing. Active cancer, paralysis/cast, bedridden/surgery, tenderness, entire leg swollen, calf >3 cm, pitting edema, collaterals, prior DVT (+1 each); alternative dx as likely (−2)
Cardiology

Wells Score for PE

Estimates the clinical probability of pulmonary embolism before testing. DVT signs 3; PE most likely 3; HR >100 1.5; immobilization/surgery 1.5; prior VTE 1.5; hemoptysis 1; cancer 1
Cardiology

PERC Rule

Rules out PE without testing when pre-test probability is already low. Age ≥50, HR ≥100, SpO2 <95%, unilateral leg swelling, hemoptysis, recent surgery/trauma, prior VTE, hormone use
Cardiology

Revised Geneva Score

Objective PE probability score that does not rely on clinician gestalt. Age >65 1, prior VTE 3, surgery/fracture 2, cancer 2, unilateral leg pain 3, hemoptysis 2, HR 75–94 3/≥95 5, leg pain on palpation + edema 4
Cardiology

Age-Adjusted D-dimer Cut-off

Raises the D-dimer cut-off with age to reduce unnecessary imaging after 50. Cut-off = age × 10 µg/L FEU (if age >50)
Cardiology

sPESI (Simplified PE Severity Index)

Identifies low-risk PE patients who may be suitable for early discharge. Age >80, cancer, chronic cardiopulmonary dz, HR ≥110, SBP <100, SaO2 <90% (1 each)
Cardiology

Revised Cardiac Risk Index (Lee)

Estimates the risk of major cardiac complications after non-cardiac surgery. High-risk surgery, IHD, CHF, cerebrovascular dz, insulin DM, Cr >2 mg/dL (1 each)
Cardiology

Framingham 10-y CHD Risk

Estimates 10-year coronary heart disease risk (Framingham). Sex-specific points from age, total cholesterol, HDL, SBP (treated/untreated), smoking, diabetes
Cardiology

ASCVD Pooled Cohort Equations

Estimates 10-year atherosclerotic cardiovascular risk to guide statin therapy (US). 10-y risk = 1 − S10^exp(ΣβX − mean) using age, sex, race, TC, HDL, SBP, HTN Rx, DM, smoking
Cardiology

SCORE2 (Europe)

Estimates 10-year cardiovascular risk for European populations. Sex/region-specific 10-y fatal + non-fatal CVD risk from age, smoking, SBP, non-HDL
Cardiology

Ankle-Brachial Index (ABI)

Ratio of ankle to arm pressure; screens for peripheral arterial disease. ABI = higher ankle SBP (DP or PT) / higher brachial SBP
Cardiology

Norepinephrine Equivalent Dose (Vasopressor Load)

Converts several vasopressors into one norepinephrine-equivalent dose. NEE = NE + Epi + (phenylephrine/10) + (dopamine/100) + (vasopressin × 2.5) [µg/kg/min; vaso U/min]
Cardiology

Vasoactive-Inotropic Score (VIS)

Quantifies total vasoactive and inotropic support, mainly after cardiac surgery. VIS = Dopa + Dobu + 100×Epi + 100×NE + 10×Milrinone + 10,000×Vasopressin (U/kg/min) (all µg/kg/min)
Cardiology

Inotrope Score (Wernovsky)

Older inotrope score (Wernovsky) for post-operative cardiac patients. IS = Dopamine + Dobutamine + 100 × Epinephrine (µg/kg/min)
Cardiology

Infusion Rate from Dose (µg/kg/min)

Converts a weight-based infusion dose into a pump rate. Rate (mL/h) = Dose × weight(kg) × 60 / concentration (µg/mL)
Cardiology

Oxygen Delivery (DO2)

Oxygen delivered to the tissues per minute. DO2 = CO × CaO2 × 10
Cardiology

Oxygen Consumption (VO2)

Oxygen consumed by the tissues per minute. VO2 = CO × (CaO2 − CvO2) × 10
Cardiology

Oxygen Extraction Ratio

Fraction of delivered oxygen taken up by tissues; rises when delivery falls. O2ER = (CaO2 − CvO2) / CaO2 = (SaO2 − SvO2) / SaO2
Cardiology

Arteriovenous O2 Difference

Difference in oxygen content between arterial and venous blood. a-vDO2 = CaO2 − CvO2
Cardiology

Venous-to-Arterial CO2 Gap (Pv-aCO2)

Venous-to-arterial CO2 gap; a raised gap suggests inadequate cardiac output. ΔPCO2 = PcvCO2 − PaCO2
Cardiology

Coronary Perfusion Pressure

Pressure that drives coronary blood flow, especially during CPR. CPP = Aortic DBP − LVEDP (or RAP during CPR)
Cardiology

Cardiac Power Output

Cardiac pumping power; the strongest haemodynamic predictor of death in cardiogenic shock. CPO = MAP × CO / 451
Cardiology

Pulmonary Artery Pulsatility Index (PAPi)

PA pulsatility index; identifies right-ventricular failure. PAPi = (PA systolic − PA diastolic) / RAP
Cardiology

Pulse Pressure Variation

Breath-to-breath change in pulse pressure; predicts fluid responsiveness in ventilated patients. PPV = (PPmax − PPmin) / [(PPmax + PPmin)/2] × 100
Cardiology

Stroke Volume Variation

Breath-to-breath change in stroke volume; predicts fluid responsiveness. SVV = (SVmax − SVmin) / SVmean × 100
Cardiology

IVC Collapsibility Index

Respiratory change in IVC diameter in spontaneously breathing patients. IVC-CI = (IVC max − IVC min) / IVC max × 100
Cardiology

IVC Distensibility Index (ventilated)

IVC distensibility in ventilated patients; predicts fluid responsiveness. dIVC = (IVC max − IVC min) / IVC min × 100
Cardiology

Passive Leg Raise Response

Change in stroke volume or output after a passive leg raise (a reversible fluid challenge). ΔSV or ΔCO after PLR / baseline × 100
Cardiology

NYHA Functional Class

Classifies heart failure symptoms by physical limitation. I no limitation; II slight (ordinary activity symptoms); III marked (less than ordinary); IV symptoms at rest
Cardiology

Ross Classification (Pediatric HF)

Heart failure classification adapted for infants and children. I asymptomatic; II mild tachypnea/diaphoresis with feeds; III marked symptoms, growth failure; IV symptoms at rest
Pulmonary & Ventilation

Alveolar Gas Equation (PAO2)

Calculates the oxygen pressure in the alveoli. PAO2 = FiO2 × (Patm − PH2O) − PaCO2 / RQ = FiO2 × (760 − 47) − PaCO2/0.8
Pulmonary & Ventilation

A–a Oxygen Gradient

Gap between alveolar and arterial oxygen; raised in V/Q mismatch, shunt or diffusion defects. A–a = PAO2 − PaO2
Pulmonary & Ventilation

a/A Ratio

Arterial/alveolar oxygen ratio; less dependent on FiO2 than the A–a gradient. a/A = PaO2 / PAO2
Pulmonary & Ventilation

P/F Ratio

Oxygenation ratio used to define ARDS severity (Berlin). P/F = PaO2 / FiO2
Pulmonary & Ventilation

S/F Ratio

Non-invasive substitute for P/F using pulse oximetry. S/F = SpO2 / FiO2 (SpO2 ≤97%)
Pulmonary & Ventilation

Oxygenation Index (OI)

Oxygenation index; accounts for airway pressure, used in children and neonates. OI = (FiO2 × MAP_airway × 100) / PaO2
Pulmonary & Ventilation

Oxygen Saturation Index (OSI)

Oxygenation index using SpO2 instead of PaO2. OSI = (FiO2 × MAP_airway × 100) / SpO2
Pulmonary & Ventilation

Arterial Oxygen Content (CaO2)

Total oxygen carried by arterial blood. CaO2 = (1.34 × Hb × SaO2) + (0.003 × PaO2)
Pulmonary & Ventilation

Venous Oxygen Content (CvO2)

Total oxygen carried by venous blood. CvO2 = (1.34 × Hb × SvO2) + (0.003 × PvO2)
Pulmonary & Ventilation

Shunt Fraction (Qs/Qt)

Fraction of cardiac output bypassing ventilated lung. Qs/Qt = (CcO2 − CaO2) / (CcO2 − CvO2)
Pulmonary & Ventilation

Dead Space Ratio (Bohr–Enghoff)

Fraction of each breath that does not take part in gas exchange. Vd/Vt = (PaCO2 − PeCO2) / PaCO2
Pulmonary & Ventilation

Minute Ventilation

Total air moved per minute. VE = Vt × RR
Pulmonary & Ventilation

Alveolar Ventilation

Air reaching the alveoli per minute; determines PaCO2. VA = (Vt − Vd) × RR
Pulmonary & Ventilation

Ventilator Adjustment for Target PaCO2

Adjusts ventilator rate to reach a target PaCO2. New RR = current RR × current PaCO2 / desired PaCO2
Pulmonary & Ventilation

Ventilator Adjustment for Target PaO2 (FiO2)

Adjusts FiO2 to reach a target PaO2. New FiO2 = current FiO2 × desired PaO2 / current PaO2
Pulmonary & Ventilation

Lung-Protective Tidal Volume

Lung-protective tidal volume based on predicted body weight. Vt = 6 mL/kg PBW (range 4–8)
Pulmonary & Ventilation

Predicted Body Weight (ARDSnet)

Predicted body weight from height and sex; the basis for ventilator settings. Male 50 + 0.91 × (height cm − 152.4); Female 45.5 + 0.91 × (height cm − 152.4)
Pulmonary & Ventilation

Static Compliance

Static respiratory system compliance; falls in ARDS, fibrosis and oedema. Cstat = Vt / (Pplat − PEEP)
Pulmonary & Ventilation

Dynamic Compliance

Dynamic compliance; includes airway resistance. Cdyn = Vt / (PIP − PEEP)
Pulmonary & Ventilation

Airway Resistance

Airway resistance from peak-to-plateau difference and flow. Raw = (PIP − Pplat) / Flow (L/s)
Pulmonary & Ventilation

Driving Pressure

Plateau minus PEEP; a driving pressure ≤15 cmH2O is linked to better ARDS survival. ΔP = Pplat − PEEP
Pulmonary & Ventilation

Mechanical Power (simplified, Gattinoni)

Energy delivered to the lungs per minute; high values are linked to lung injury. MP = 0.098 × RR × Vt(L) × (Ppeak − ΔP/2)
Pulmonary & Ventilation

Mean Airway Pressure

Average pressure in the airways; drives oxygenation. MAP ≈ [(PIP × Ti) + (PEEP × Te)] / (Ti + Te)
Pulmonary & Ventilation

Time Constant

How quickly the lungs fill and empty; guides expiratory time. τ = Compliance × Resistance
Pulmonary & Ventilation

I:E Ratio

Ratio of inspiratory to expiratory time. I:E = Ti : (60/RR − Ti)
Pulmonary & Ventilation

Rapid Shallow Breathing Index (RSBI)

Predicts success of weaning from mechanical ventilation. RSBI = RR / Vt (L)
Pulmonary & Ventilation

ROX Index (HFNC)

Predicts high-flow nasal cannula failure and the need for intubation. ROX = (SpO2/FiO2) / RR
Pulmonary & Ventilation

HFNC Flow (pediatric)

Starting high-flow nasal cannula flow for children by weight. Flow = 2 L/kg/min for ≤10 kg + 0.5 L/kg/min each kg above 10 (max ~50–60 L/min)
Pulmonary & Ventilation

Oxygen Cylinder Duration

How long an oxygen cylinder will last at a given flow. Time (min) = (Cylinder pressure psi − 200) × factor / flow (L/min); factor D=0.16, E=0.28, H=3.14
Pulmonary & Ventilation

FiO2 Estimate by Nasal Cannula

Approximate FiO2 delivered by nasal cannula. FiO2 ≈ 21% + 4% × flow (L/min)
Pulmonary & Ventilation

FEV1/FVC Ratio

Confirms airflow obstruction on spirometry. Ratio = FEV1 / FVC
Pulmonary & Ventilation

GOLD COPD Spirometric Grade

Grades airflow limitation in COPD. Post-bronchodilator FEV1 % predicted
Pulmonary & Ventilation

Bronchodilator Reversibility

Tests whether airflow obstruction improves after a bronchodilator. ΔFEV1 = (post − pre) / predicted × 100 (ERS 2022) or ≥12% and 200 mL
Pulmonary & Ventilation

Peak Expiratory Flow % Predicted/Best

Peak flow compared with predicted or personal best; asthma action-plan zones. PEF% = measured PEF / predicted or personal best × 100
Pulmonary & Ventilation

PEF Diurnal Variability

Day-to-day peak-flow variability; supports an asthma diagnosis. Variability = (PEFmax − PEFmin) / mean PEF × 100
Pulmonary & Ventilation

Pack-Years

Cumulative tobacco exposure; used for lung cancer screening eligibility. Pack-years = (cigarettes/day ÷ 20) × years smoked
Pulmonary & Ventilation

CURB-65

Severity score for community-acquired pneumonia; guides site of care. Confusion, Urea >7 mmol/L (BUN >19), RR ≥30, SBP <90 or DBP ≤60, Age ≥65 (1 each)
Pulmonary & Ventilation

Pneumonia Severity Index (PSI/PORT)

Pneumonia Severity Index: detailed mortality risk score for community-acquired pneumonia. Points for age, sex, nursing home, comorbidities, exam and lab findings
Pulmonary & Ventilation

Light's Criteria (pleural effusion)

Classifies a pleural effusion as exudate or transudate. Exudate if any: Pleural/serum protein >0.5; pleural/serum LDH >0.6; pleural LDH >2/3 ULN serum
Pulmonary & Ventilation

Serum–Pleural Albumin Gradient

Identifies transudates mislabelled as exudates (e.g. after diuretics). Gradient = serum albumin − pleural albumin
Pulmonary & Ventilation

STOP-BANG

Screens for obstructive sleep apnoea. Snoring, Tired, Observed apnea, Pressure (HTN), BMI >35, Age >50, Neck >40 cm, Gender male (1 each)
Pulmonary & Ventilation

Apnea-Hypopnea Index (AHI)

Severity of sleep apnoea from events per hour of sleep. AHI = (apneas + hypopneas) / total sleep time (h)
Pulmonary & Ventilation

Endotracheal Tube Size (pediatric, uncuffed)

Endotracheal tube size for children by age. ID = (age/4) + 4
Pulmonary & Ventilation

ETT Depth at Lips (pediatric)

Tube insertion depth at the lips for children. Depth = ID × 3 (or age/2 + 12)
Pulmonary & Ventilation

ETT Depth (neonate)

Tube insertion depth for neonates by weight. Depth (cm at lip) = weight (kg) + 6
Pulmonary & Ventilation

ETT Depth (adult)

Typical adult tube depth at the teeth. ~21 cm women, ~23 cm men at incisors
Pulmonary & Ventilation

Suction Catheter Size

Suction catheter size for an endotracheal tube. French = ETT ID (mm) × 2
Pulmonary & Ventilation

Lung Injury Score (Murray)

Murray score: severity of acute lung injury; guides ECMO referral. Average of: CXR quadrants, P/F, PEEP, compliance (each 0–4)
Pulmonary & Ventilation

Westley Croup Score

Grades croup severity to guide treatment. Stridor, retractions, air entry, cyanosis, consciousness
Pulmonary & Ventilation

Pediatric Respiratory Assessment Measure (PRAM)

Grades acute asthma severity in children. SpO2, suprasternal retraction, scalene use, air entry, wheeze
Pulmonary & Ventilation

Silverman–Andersen Score (neonate)

Grades respiratory distress in newborns. Chest movement, intercostal retraction, xiphoid retraction, nasal flaring, grunt (0–2 each)
Critical Care Scores

qSOFA

Bedside screen for patients with infection at high risk of poor outcome. RR ≥22, altered mentation, SBP ≤100 (1 each)
Critical Care Scores

SOFA Score

Measures organ dysfunction in critical illness; a rise of ≥2 defines sepsis. Respiration (P/F), coagulation (platelets), liver (bilirubin), CV (MAP/vasopressors), CNS (GCS), renal (Cr/UO); 0–4 each
Critical Care Scores

Phoenix Sepsis Score (pediatric, 2024)

Defines sepsis and septic shock in children (2024 criteria). Respiratory (0–3), cardiovascular (0–6), coagulation (0–2), neurologic (0–2)
Critical Care Scores

pSOFA (pediatric SOFA)

Age-adjusted organ dysfunction score for children. Age-adjusted SOFA (MAP, Cr thresholds by age)
Critical Care Scores

SIRS Criteria

Classic criteria for a systemic inflammatory response. Temp >38 or <36 °C; HR >90; RR >20 or PaCO2 <32; WBC >12 or <4 ×10⁹/L or >10% bands
Critical Care Scores

APACHE II

ICU mortality prediction from physiology, age and chronic health. Acute physiology score (12 variables) + age points + chronic health points
Critical Care Scores

SAPS II

ICU mortality prediction (SAPS II). 17 variables (12 physiological, age, admission type, 3 chronic diseases)
Critical Care Scores

PRISM III

Paediatric ICU mortality prediction (PRISM III). 17 physiological variables (worst in first 12–24 h)
Critical Care Scores

PIM3 (Pediatric Index of Mortality 3)

Paediatric ICU mortality prediction at admission (PIM3). Logit from SBP, pupils, FiO2/PaO2, BE, ventilation, elective admission, recovery from procedure, bypass, diagnoses
Critical Care Scores

Standardized Mortality Ratio (SMR)

Observed deaths divided by expected deaths; benchmarks ICU performance. SMR = Observed deaths / Expected deaths (from model)
Critical Care Scores

NEWS2 (National Early Warning Score)

Early warning score that triggers clinical review in deteriorating adults. RR, SpO2, supplemental O2, SBP, HR, consciousness, temperature
Critical Care Scores

PEWS (Pediatric Early Warning Score)

Early warning score for children on the ward. Behavior, cardiovascular, respiratory (0–3 each) + nebs/vomiting modifiers
Critical Care Scores

Richmond Agitation-Sedation Scale (RASS)

Standard scale for agitation and sedation depth in the ICU. +4 combative to −5 unarousable
Critical Care Scores

CAM-ICU

Bedside test for delirium in ICU patients, including ventilated ones. Acute change/fluctuation + inattention + (altered LOC or disorganized thinking)
Critical Care Scores

Critical-Care Pain Observation Tool (CPOT)

Pain assessment for patients who cannot self-report. Facial expression, body movement, muscle tension, ventilator compliance/vocalization (0–2 each)
Critical Care Scores

State Behavioral Scale (SBS, pediatric)

Sedation and agitation scale for ventilated children. −3 unresponsive to +2 agitated
Critical Care Scores

COMFORT-B Scale (pediatric)

Sedation assessment for children in intensive care. Alertness, calmness, respiratory response/crying, movement, muscle tone, facial tension (1–5 each)
Critical Care Scores

Withdrawal Assessment Tool-1 (WAT-1)

Screens for iatrogenic opioid and benzodiazepine withdrawal in children. 11 items (stool, vomiting, fever, tremor, sweating, yawning, etc.)
Critical Care Scores

Fluid Balance

Net fluid balance over a period. Net = Total intake − Total output (urine, drains, insensible)
Critical Care Scores

Percent Fluid Overload (pediatric)

Fluid overload as a percentage of body weight; >10–20% is linked to worse outcomes in children. %FO = (Fluid in − Fluid out, L) / ICU admission weight (kg) × 100
Critical Care Scores

Insensible Water Loss

Estimates unmeasured fluid loss through skin and breathing. Adult ≈ 10 mL/kg/day (+10% per °C above 37); child ≈ 300–400 mL/m²/day
Critical Care Scores

Cerebral Perfusion Pressure

Pressure that perfuses the brain; key target in traumatic brain injury. CPP = MAP − ICP
Critical Care Scores

Glasgow–Blatchford Score

Risk score for upper GI bleeding; identifies patients safe for outpatient care. BUN, Hb (sex-specific), SBP, HR, melena, syncope, hepatic disease, cardiac failure
Critical Care Scores

Sequential Lactate (Shock Persistence)

Repeat lactate to judge the response to resuscitation. Repeat lactate within 2–4 h if >2 mmol/L
Critical Care Scores

Massive Transfusion Prediction (ABC Score)

Predicts the need for massive transfusion after trauma. Penetrating mechanism, SBP ≤90, HR ≥120, positive FAST (1 each)
Infectious Disease

Absolute Neutrophil Count (ANC)

Neutrophils available to fight infection; defines neutropenia. ANC = WBC × (% segmented + % bands) / 100
Infectious Disease

Absolute Lymphocyte Count

Absolute lymphocyte count from the differential. ALC = WBC × % lymphocytes / 100
Infectious Disease

Neutrophil-to-Lymphocyte Ratio

Inflammation marker; rises with physiological stress and infection. NLR = ANC / ALC
Infectious Disease

Immature-to-Total Neutrophil Ratio (I:T)

Immature-to-total neutrophil ratio; supports a diagnosis of neonatal sepsis. I:T = (bands + metamyelocytes + myelocytes) / (total neutrophils)
Infectious Disease

CSF WBC Correction for Traumatic Tap

Corrects CSF white cells for blood contamination after a traumatic tap. Predicted CSF WBC = CSF RBC × (blood WBC / blood RBC); or subtract 1 WBC per 500–1000 RBC
Infectious Disease

CSF:Serum Glucose Ratio

Low ratios suggest bacterial, tuberculous or fungal meningitis. Ratio = CSF glucose / serum glucose
Infectious Disease

Bacterial Meningitis Score (pediatric)

Identifies children with CSF pleocytosis at very low risk of bacterial meningitis. +Gram stain 2; CSF ANC ≥1000 1; CSF protein ≥80 1; blood ANC ≥10,000 1; seizure 1
Infectious Disease

Centor / McIsaac Score

Estimates the probability of streptococcal pharyngitis. Fever, tonsillar exudate, tender anterior nodes, absent cough (+1 each); age 3–14 +1; ≥45 −1
Infectious Disease

ALVARADO (MANTRELS) Score

Estimates the probability of appendicitis in adults. Migration 1, Anorexia 1, Nausea 1, RLQ tenderness 2, Rebound 1, Elevated temp 1, Leukocytosis 2, Left shift 1
Infectious Disease

Pediatric Appendicitis Score

Estimates the probability of appendicitis in children. Cough/hop tenderness 2, RLQ tenderness 2, anorexia, fever, nausea, migration, leukocytosis, neutrophilia (1 each)
Infectious Disease

LRINEC Score (necrotizing fasciitis)

Laboratory score for necrotising fasciitis. CRP, WBC, Hb, Na, creatinine, glucose
Infectious Disease

Kocher Criteria (septic hip)

Predicts septic arthritis of the hip in children with a painful hip. Non-weight-bearing, fever >38.5, ESR >40, WBC >12,000 (1 each)
Infectious Disease

Duke Criteria (endocarditis, 2023)

Diagnostic criteria for infective endocarditis. Major: blood cultures, imaging; minor: predisposition, fever, vascular, immunologic, microbiologic
Infectious Disease

Aminoglycoside Extended-Interval (Hartford nomogram)

Extended-interval gentamicin dosing and monitoring. Gentamicin 7 mg/kg; level at 6–14 h plotted on nomogram → q24/q36/q48 h
Infectious Disease

CD4 Percentage

CD4 cells as a share of lymphocytes; useful in children with HIV. CD4% = CD4 count / total lymphocyte count × 100
Anthropometry & Body Composition

Body Mass Index (BMI)

Weight relative to height; screens for under- and overweight in adults. BMI = weight (kg) / height (m)²
Anthropometry & Body Composition

BMI-for-Age (pediatric)

BMI compared with WHO/CDC references for a child's age and sex. BMI plotted on WHO/CDC percentile or z-score charts
Anthropometry & Body Composition

Body Surface Area (Mosteller)

Body surface area (Mosteller); used for chemotherapy and indexing. BSA = √[height (cm) × weight (kg) / 3600]
Anthropometry & Body Composition

Body Surface Area (Du Bois)

Body surface area (Du Bois). BSA = 0.007184 × weight^0.425 × height^0.725
Anthropometry & Body Composition

Body Surface Area (Haycock)

Body surface area (Haycock); validated in infants and children. BSA = 0.024265 × weight^0.5378 × height^0.3964
Anthropometry & Body Composition

Body Surface Area (weight only, child)

Body surface area from weight alone in children. BSA = (4W + 7) / (W + 90)
Anthropometry & Body Composition

Ideal Body Weight (Devine)

Ideal body weight (Devine); used for dosing some drugs. Male 50 + 2.3 × (inches over 60); Female 45.5 + 2.3 × (inches over 60)
Anthropometry & Body Composition

Ideal Body Weight (pediatric, McLaren)

Ideal body weight for children from the height percentile. Weight at the same percentile as the child's height percentile (growth chart)
Anthropometry & Body Composition

Adjusted Body Weight

Dosing weight for obese patients between ideal and actual weight. AdjBW = IBW + 0.4 × (actual weight − IBW)
Anthropometry & Body Composition

Percent Ideal Body Weight

Actual weight as a percentage of ideal body weight. %IBW = actual weight / IBW × 100
Anthropometry & Body Composition

Lean Body Weight (Janmahasatian)

Fat-free mass; used for dosing anaesthetics and some antibiotics. Male: 9270 × W / (6680 + 216 × BMI); Female: 9270 × W / (8780 + 244 × BMI)
Anthropometry & Body Composition

Body Fat % (Deurenberg)

Estimates body fat percentage from BMI, age and sex. BF% = 1.20 × BMI + 0.23 × age − 10.8 × sex − 5.4 (sex: M=1, F=0)
Anthropometry & Body Composition

Waist-to-Hip Ratio

Marker of abdominal (central) obesity and cardiometabolic risk. WHR = waist / hip circumference
Anthropometry & Body Composition

Waist-to-Height Ratio

Simple marker of central obesity; keep waist below half your height. WHtR = waist / height
Anthropometry & Body Composition

Ponderal Index (Rohrer)

Weight relative to length in newborns; detects asymmetric growth restriction. PI = weight (g) × 100 / length (cm)³
Anthropometry & Body Composition

Mid-Upper Arm Circumference (MUAC) cut-offs

Arm circumference screen for acute malnutrition in children 6–59 months. Direct measurement (6–59 months)
Anthropometry & Body Composition

Weight-for-Height/Length z-score

Weight-for-length/height z-score; identifies wasting. z = (observed − median reference) / SD (WHO LMS method: z = [(X/M)^L − 1] / (L × S))
Anthropometry & Body Composition

Height/Length-for-Age z-score

Height-for-age z-score; identifies stunting. WHO LMS z-score
Anthropometry & Body Composition

Weight-for-Age z-score

Weight-for-age z-score; identifies underweight. WHO LMS z-score
Anthropometry & Body Composition

Percent Weight Loss

Unintentional weight loss as a percentage; a malnutrition criterion. %WL = (usual − current weight) / usual × 100
Anthropometry & Body Composition

Mid-Parental Target Height

Genetic target height of a child from parents' heights. Boy = (father + mother + 13 cm)/2; Girl = (father + mother − 13 cm)/2
Anthropometry & Body Composition

Height Velocity

Growth speed in cm per year; slow velocity needs evaluation. HV = (height2 − height1) / interval (years)
Anthropometry & Body Composition

Corrected Age (prematurity)

Age corrected for prematurity for growth and development assessment. Corrected age = chronological age − (40 − gestational age at birth, weeks)
Anthropometry & Body Composition

Estimated Weight from Age (APLS)

Estimated child weight from age for emergencies (APLS). 0–12 mo: 0.5 × age(mo) + 4; 1–5 y: 2 × age + 8; 6–12 y: 3 × age + 7
Anthropometry & Body Composition

Height from Knee Height (Chumlea)

Estimates height from knee height when standing height cannot be measured. Men = 64.19 − 0.04×age + 2.02×KH; Women = 84.88 − 0.24×age + 1.83×KH
Nutrition & Metabolism

Basal Metabolic Rate (Harris–Benedict)

Basal energy needs (Harris–Benedict). Male: 66.5 + 13.75W + 5.003H − 6.755A; Female: 655.1 + 9.563W + 1.850H − 4.676A
Nutrition & Metabolism

Resting Energy Expenditure (Mifflin–St Jeor)

Resting energy needs (Mifflin–St Jeor); the most accurate predictive equation in adults. 10W + 6.25H − 5A + 5 (male) or −161 (female)
Nutrition & Metabolism

Schofield Equation (children)

Resting energy needs in children (Schofield). Age/sex-specific: e.g., boys 3–10 y: 22.7W + 495; girls 3–10 y: 22.5W + 499
Nutrition & Metabolism

Weir Equation (indirect calorimetry)

Energy expenditure from measured oxygen consumption and CO2 production. REE = [3.941 × VO2 (L/min) + 1.11 × VCO2] × 1440
Nutrition & Metabolism

Respiratory Quotient

Ratio of CO2 produced to O2 consumed; reflects fuel use and overfeeding. RQ = VCO2 / VO2
Nutrition & Metabolism

Holliday–Segar Caloric Requirement

Daily calorie needs in children by weight (Holliday–Segar). 100 kcal/kg first 10 kg + 50 kcal/kg next 10 kg + 20 kcal/kg thereafter
Nutrition & Metabolism

ICU Calorie Target (simple)

Simple weight-based calorie target for critically ill adults. 25–30 kcal/kg/day (start ~70% in acute phase)
Nutrition & Metabolism

Protein Requirement

Daily protein requirement by clinical situation. Healthy 0.8 g/kg; ICU 1.2–2.0 g/kg; CKD (non-dialysis) 0.6–0.8; dialysis 1.0–1.2; child PICU ≥1.5
Nutrition & Metabolism

Nitrogen Balance

Protein intake minus nitrogen losses; negative balance means catabolism. N balance = (protein intake g / 6.25) − (UUN g + 4)
Nutrition & Metabolism

Catch-Up Growth Requirement

Calorie needs for catch-up growth in malnourished children. kcal/kg/day = [120 kcal/kg × IBW for height] / actual weight
Nutrition & Metabolism

Glucose Infusion Rate (GIR)

Glucose infusion rate in mg/kg/min; key in neonatal and hypoglycaemia care. GIR = [Dextrose % × rate (mL/h) × 10] / [weight (kg) × 60] = %Dex × mL/kg/day / 144
Nutrition & Metabolism

Parenteral Nutrition Osmolarity

Estimates parenteral nutrition osmolarity to choose peripheral or central access. ≈ (Dextrose g/L × 5) + (Amino acid g/L × 10) + (electrolyte mEq/L × 2)
Nutrition & Metabolism

Calories from Dextrose

Calories supplied by intravenous dextrose. kcal = grams dextrose × 3.4
Nutrition & Metabolism

Calories from IV Lipid

Calories supplied by intravenous lipid emulsion. 20% emulsion: 2 kcal/mL (10 kcal/g lipid ≈ 9 + glycerol)
Nutrition & Metabolism

Infant Formula Caloric Density

Calorie density of infant formulas. Standard 20 kcal/oz ≈ 0.67 kcal/mL; concentrated 24 kcal/oz = 0.8; 27 = 0.9; 30 = 1.0 kcal/mL
Nutrition & Metabolism

Infant Daily Intake

Daily calorie intake of an infant from feed volume. kcal/kg/day = volume (mL/kg/day) × caloric density (kcal/mL)
Nutrition & Metabolism

Refeeding Syndrome Risk (NICE)

Identifies patients at risk of refeeding syndrome (NICE). 1 major (BMI <16, WL >15%, little intake >10 d, low K/PO4/Mg) or 2 minor criteria
Nutrition & Metabolism

NUTRIC Score (modified)

Nutrition risk in the critically ill (NUTRIC). Age, APACHE II, SOFA, comorbidities, days hospital→ICU (IL-6 optional)
Nutrition & Metabolism

NRS-2002

Screens hospital patients for nutritional risk (NRS-2002). Nutritional status (0–3) + disease severity (0–3) + age ≥70 (1)
Nutrition & Metabolism

MUST (Malnutrition Universal Screening Tool)

Screens adults for malnutrition (MUST). BMI score + weight-loss score + acute disease effect score
Nutrition & Metabolism

STRONGkids (pediatric)

Screens hospitalised children for malnutrition risk (STRONGkids). Subjective clinical assessment, high-risk disease, intake/losses, weight loss (max 5)
Nutrition & Metabolism

Maintenance Fluids (Holliday–Segar, 4-2-1)

Hourly maintenance fluids for children by weight (4-2-1 rule). 4 mL/kg/h first 10 kg + 2 mL/kg/h next 10 kg + 1 mL/kg/h each kg >20
Nutrition & Metabolism

Maintenance Fluids (100-50-20, daily)

Daily maintenance fluids by weight (100-50-20 rule). 100 mL/kg/day first 10 kg + 50 mL/kg/day next 10 + 20 mL/kg/day thereafter
Nutrition & Metabolism

Maintenance Fluids by BSA

Daily maintenance fluids by body surface area. 1500 mL/m²/day
Nutrition & Metabolism

Dehydration Deficit

Fluid deficit to replace in dehydration. Deficit (mL) = % dehydration × weight (kg) × 10
Nutrition & Metabolism

Percent Dehydration by Weight

Degree of dehydration from weight loss. % = (pre-illness wt − current wt) / pre-illness wt × 100
Nutrition & Metabolism

Clinical Dehydration Scale (CDS)

Clinical dehydration scale for young children with gastroenteritis. General appearance, eyes, mucous membranes, tears (0–2 each)
Pharmacology & Dosing

Weight-Based Dose

Drug dose from mg/kg and weight, with an optional maximum. Dose = dose per kg × weight (kg)
Pharmacology & Dosing

BSA-Based Dose

Drug dose per m² of body surface area. Dose = dose per m² × BSA
Pharmacology & Dosing

Volume to Administer

Volume of a solution needed for a dose. Volume = Desired dose / Concentration (mg/mL) (D/H × Q)
Pharmacology & Dosing

IV Drip Rate (gravity)

Gravity drip rate in drops per minute. Drops/min = Volume (mL) × drop factor (gtt/mL) / time (min)
Pharmacology & Dosing

IV Infusion Rate

Pump rate in mL/h. Rate (mL/h) = Total volume (mL) / time (h)
Pharmacology & Dosing

Infusion Time

How long an infusion will take. Time (h) = Volume (mL) / rate (mL/h)
Pharmacology & Dosing

Concentration of Solution

Concentration of a prepared solution. Concentration = amount of drug / total volume; % w/v = g per 100 mL
Pharmacology & Dosing

Dilution (C1V1 = C2V2)

Dilution: how much stock to use for a target concentration. V1 = (C2 × V2) / C1
Pharmacology & Dosing

Infusion Dose Delivered

Dose actually delivered by an infusion running at a given rate. Dose (µg/kg/min) = Rate (mL/h) × concentration (µg/mL) / [weight × 60]
Pharmacology & Dosing

Heparin Infusion (weight-based)

Weight-based unfractionated heparin bolus and infusion. Bolus 80 U/kg, then 18 U/kg/h; adjust by aPTT/anti-Xa nomogram
Pharmacology & Dosing

Insulin Infusion (DKA)

Fixed-rate insulin infusion for diabetic ketoacidosis. 0.05–0.1 U/kg/h (no bolus in children)
Pharmacology & Dosing

Pediatric Dose (Clark's Rule)

Paediatric dose scaled from the adult dose by weight (Clark). Child dose = adult dose × weight (lb) / 150
Pharmacology & Dosing

Pediatric Dose (Young's Rule)

Paediatric dose scaled from the adult dose by age (Young). Child dose = adult dose × age / (age + 12)
Pharmacology & Dosing

Pediatric Dose by BSA Ratio

Paediatric dose scaled from the adult dose by body surface area. Child dose = adult dose × BSA child / 1.73
Pharmacology & Dosing

Loading Dose

Loading dose needed to reach a target concentration quickly. LD = Vd × target concentration / F (× S)
Pharmacology & Dosing

Maintenance Dose

Maintenance dose to keep a steady-state concentration. MD = CL × Css × τ / F
Pharmacology & Dosing

Elimination Rate Constant

Elimination rate constant from two drug levels. ke = ln(C1/C2) / Δt = 0.693 / t½
Pharmacology & Dosing

Half-Life

Drug half-life. t½ = 0.693 × Vd / CL = 0.693 / ke
Pharmacology & Dosing

Volume of Distribution

Apparent volume into which a drug distributes. Vd = Dose / C0
Pharmacology & Dosing

Clearance

Drug clearance. CL = ke × Vd = Dose × F / AUC
Pharmacology & Dosing

Average Steady-State Concentration

Average steady-state concentration on a regular regimen. Css,avg = (F × Dose) / (CL × τ)
Pharmacology & Dosing

Bioavailability

Bioavailability: fraction of an oral dose reaching the circulation. F = (AUC oral × Dose IV) / (AUC IV × Dose oral)
Pharmacology & Dosing

Phenytoin Correction for Albumin (Sheiner–Tozer)

Corrects a total phenytoin level for low albumin, which raises the free fraction. C corr = C measured / [(0.2 × albumin g/dL) + 0.1] (use 0.1 × alb + 0.1 if CrCl <10)
Pharmacology & Dosing

Digoxin Maintenance (Jusko)

Estimates digoxin clearance and maintenance dose from weight and renal function. CL(mL/min) = 0.8 × wt + CrCl (HF: 0.33 × wt + 0.9 × CrCl); MD = Css × CL × τ
Pharmacology & Dosing

Digoxin Immune Fab Dose

Number of digoxin-specific antibody vials needed for toxicity. Vials = [serum digoxin (ng/mL) × weight (kg)] / 100 (or mg ingested × 0.8 / 0.5)
Pharmacology & Dosing

Opioid Morphine Milligram Equivalents (MME)

Converts opioid doses into oral morphine equivalents to judge overdose risk. MME/day = Σ(daily dose × conversion factor); oral morphine 1, oxycodone 1.5, hydromorphone 4 (oral), tramadol 0.2
Pharmacology & Dosing

Opioid Rotation

Safer dose when switching opioids, allowing for incomplete cross-tolerance. New dose = equianalgesic dose × (1 − 25–50% cross-tolerance reduction)
Pharmacology & Dosing

Corticosteroid Equivalence

Converts between equivalent corticosteroid doses. Hydrocortisone 20 = prednisone/prednisolone 5 = methylprednisolone 4 = dexamethasone 0.75 mg
Pharmacology & Dosing

Stress-Dose Hydrocortisone (pediatric)

Stress-dose hydrocortisone for children with adrenal insufficiency. 50–100 mg/m² IV bolus (≈ 2 mg/kg), then 50–100 mg/m²/day divided
Pharmacology & Dosing

Acetaminophen Toxicity (Rumack–Matthew)

Plots a timed paracetamol level to decide on acetylcysteine treatment. Plot 4–24 h level on nomogram; treatment line 150 µg/mL at 4 h
Pharmacology & Dosing

Acetaminophen Toxic Dose Ingested

Paracetamol dose ingested per kg, used to assess toxicity risk. Dose = mg ingested / weight (kg)
Pharmacology & Dosing

N-Acetylcysteine IV Regimen

Three-bag intravenous acetylcysteine regimen for paracetamol poisoning. 150 mg/kg over 1 h → 50 mg/kg over 4 h → 100 mg/kg over 16 h (or 2-bag SNAP)
Pharmacology & Dosing

Iron Ingestion Toxicity

Elemental iron ingested per kg; predicts the severity of iron poisoning. Elemental iron mg/kg = tablets × elemental Fe per tablet / weight
Pharmacology & Dosing

Iron Deficit (Ganzoni)

Total iron deficit for intravenous iron replacement (Ganzoni). Deficit (mg) = weight × (target Hb − actual Hb, g/dL) × 2.4 + iron stores (500 mg; 15 mg/kg if <35 kg)
Pharmacology & Dosing

Local Anesthetic Maximum Dose

Maximum safe dose of local anaesthetic by weight. Lidocaine 4.5 mg/kg (7 with epi); bupivacaine 2.5 mg/kg (3 with epi); ropivacaine 3 mg/kg
Pharmacology & Dosing

Lipid Emulsion for LAST

Lipid emulsion rescue for local anaesthetic systemic toxicity. 20% lipid 1.5 mL/kg bolus over 2–3 min, then 0.25 mL/kg/min
Pharmacology & Dosing

Epinephrine for Anaphylaxis (IM)

Intramuscular adrenaline dose for anaphylaxis. 0.01 mg/kg of 1 mg/mL (1:1000), max 0.5 mg (adult) / 0.3 mg (child)
Pharmacology & Dosing

Epinephrine in Cardiac Arrest

Adrenaline dose in cardiac arrest. 0.01 mg/kg IV/IO of 0.1 mg/mL (=0.1 mL/kg), max 1 mg
Pharmacology & Dosing

Adenosine Dose (SVT)

Adenosine dose for supraventricular tachycardia. 0.1 mg/kg rapid IV (max 6 mg), then 0.2 mg/kg (max 12 mg)
Pharmacology & Dosing

Defibrillation/Cardioversion Energy (pediatric)

Defibrillation and cardioversion energy for children. Defib 2 J/kg → 4 J/kg (≤10 J/kg or adult max); synchronized cardioversion 0.5–1 → 2 J/kg
Pharmacology & Dosing

Rapid Sequence Intubation Doses

Drug doses for rapid sequence intubation. Ketamine 1–2 mg/kg; etomidate 0.3 mg/kg; rocuronium 1–1.2 mg/kg; succinylcholine 1.5 mg/kg (2 infants)
Pharmacology & Dosing

Sugammadex Dose

Sugammadex dose to reverse rocuronium or vecuronium. 2 mg/kg (TOF ≥2); 4 mg/kg (deep block); 16 mg/kg (immediate reversal of 1.2 mg/kg rocuronium)
Pharmacology & Dosing

Antibiotic Dosing Adjustment in Renal Impairment

Proportional dose reduction in renal impairment. Adjusted dose = normal dose × (patient CrCl / normal CrCl) or extend interval
Pharmacology & Dosing

Warfarin Weekly Dose Adjustment

Weekly warfarin dose adjustment by INR. Adjust total weekly dose by 5–20% based on INR deviation
Pharmacology & Dosing

Enoxaparin Dosing

Enoxaparin dose by indication and renal function. Treatment 1 mg/kg q12h (or 1.5 mg/kg daily); prophylaxis 40 mg daily; CrCl <30: 1 mg/kg daily; infant <2 mo 1.5–1.75 mg/kg q12h
Pharmacology & Dosing

Protamine Dose for Heparin Reversal

Protamine dose to reverse unfractionated heparin. 1 mg protamine per 100 U heparin given in last 2–3 h (max 50 mg)
Pharmacology & Dosing

Prothrombin Complex Concentrate (4F-PCC)

Prothrombin complex concentrate dose for urgent warfarin reversal. INR 2–4: 25 U/kg; 4–6: 35 U/kg; >6: 50 U/kg (or fixed 1000–2000 U)
Pediatrics & Neonatology

APGAR Score

Rapid assessment of a newborn's condition at 1 and 5 minutes. Appearance, Pulse, Grimace, Activity, Respiration (0–2 each) at 1 and 5 min
Pediatrics & Neonatology

Ballard Score (New Ballard)

Estimates gestational age of a newborn from physical and neuromuscular maturity. Neuromuscular + physical maturity (6 items each)
Pediatrics & Neonatology

Neonatal Blood Volume

Estimated circulating blood volume by age. 80–90 mL/kg term; 90–105 mL/kg preterm; child 70–80; adult 65–70
Pediatrics & Neonatology

Partial Exchange Transfusion (polycythemia)

Volume for partial exchange transfusion in neonatal polycythaemia. Volume = Blood volume × (observed Hct − desired Hct) / observed Hct
Pediatrics & Neonatology

Double-Volume Exchange Transfusion

Volume for double-volume exchange transfusion in severe jaundice. Volume = 2 × blood volume (≈160–180 mL/kg)
Pediatrics & Neonatology

Bilirubin Phototherapy Threshold (AAP 2022)

Hour-specific bilirubin thresholds for phototherapy (AAP 2022). Plot TSB on hour-specific nomogram by GA and neurotoxicity risk factors
Pediatrics & Neonatology

Bilirubin:Albumin Ratio

Bilirubin relative to albumin; adds neurotoxicity information to the bilirubin level. B/A = TSB (mg/dL) / albumin (g/dL)
Pediatrics & Neonatology

Rate of Rise of Bilirubin

Speed of bilirubin rise; a fast rise suggests haemolysis. ΔTSB / Δt
Pediatrics & Neonatology

Neonatal Early-Onset Sepsis Calculator (Kaiser)

Probability of early-onset sepsis in newborns ≥34 weeks (Kaiser). Bayesian model: GA, max maternal temp, ROM duration, GBS status, intrapartum antibiotics, clinical exam
Pediatrics & Neonatology

Neonatal Hypoglycemia Thresholds

Glucose thresholds for treating neonatal hypoglycaemia. Plasma glucose (AAP/PES)
Pediatrics & Neonatology

Dextrose Bolus (hypoglycemia)

Dextrose bolus for hypoglycaemia by weight. D10W 2 mL/kg (neonate); D10 2–5 mL/kg or D25 2–4 mL/kg (child); "rule of 50": % × mL/kg = 50
Pediatrics & Neonatology

Neonatal Maintenance Fluids by Day

Daily fluid needs in the first days of life. Day 1: 60–80; day 2: 80–100; day 3: 100–120; day 4+: 120–150 mL/kg/day (term)
Pediatrics & Neonatology

Expected Neonatal Weight Loss

Newborn weight loss since birth; >10% needs a feeding review. % weight loss = (birth wt − current wt) / birth wt × 100
Pediatrics & Neonatology

Neonatal Growth Velocity (Patel)

Growth velocity in preterm infants (exponential method). GV = 1000 × ln(Wn/W1) / (Dn − D1)
Pediatrics & Neonatology

Postmenstrual Age

Postmenstrual age = gestational age at birth + chronological age. PMA = gestational age at birth + chronological age (weeks)
Pediatrics & Neonatology

Umbilical Arterial Catheter Length

Insertion length of an umbilical arterial catheter. UAC (high) = 3 × birth weight (kg) + 9 cm (or BW × 4 + 7 Wright)
Pediatrics & Neonatology

Umbilical Venous Catheter Length

Insertion length of an umbilical venous catheter. UVC = (UAC length / 2) + 1 cm (or 1.5 × BW + 5.5)
Pediatrics & Neonatology

Pediatric Normal Systolic BP (lower limit)

Lower limit of acceptable systolic BP in children (defines hypotension). Hypotension if SBP < 70 + (2 × age in years) (1–10 y); <60 neonate; <90 >10 y
Pediatrics & Neonatology

Pediatric Median Systolic BP

Expected median systolic BP in children by age. SBP ≈ 90 + 2 × age (years)
Pediatrics & Neonatology

Pediatric Hypertension (AAP 2017)

Diagnoses hypertension in children from BP percentiles (AAP 2017). BP vs age/sex/height percentile (≥13 y adult thresholds)
Pediatrics & Neonatology

Pediatric Fluid Bolus

Fluid bolus volume for children in shock. 10–20 mL/kg isotonic crystalloid (10 mL/kg in cardiac dysfunction or neonate)
Pediatrics & Neonatology

Pediatric Blood Transfusion Volume

Red-cell transfusion volume for a target haemoglobin rise in children. Volume (mL) = weight × desired Hb rise (g/dL) × 4 (or Hct-based: wt × ΔHct × 1)
Pediatrics & Neonatology

Platelet Transfusion Volume (pediatric)

Platelet transfusion volume for children. 10–15 mL/kg
Pediatrics & Neonatology

FFP / Cryoprecipitate Dose

Plasma and cryoprecipitate doses by weight. FFP 10–15 mL/kg; cryo 1 unit per 5–10 kg (5 mL/kg)
Pediatrics & Neonatology

Pediatric Urine Output Normal

Normal urine output by age. Infant 2 mL/kg/h; child 1 mL/kg/h; adolescent 0.5 mL/kg/h
Pediatrics & Neonatology

Pediatric Respiratory Rate Norms

Normal respiratory rate by age. Newborn 30–60; infant 30–50; toddler 24–40; school age 18–30; adolescent 12–20
Pediatrics & Neonatology

Pediatric Heart Rate Norms (awake)

Normal heart rate by age. Newborn 100–205; infant 100–180; toddler 98–140; preschool 80–120; school 75–118; adolescent 60–100
Pediatrics & Neonatology

RACHS-1 / STAT Mortality Category

Mortality risk category for congenital heart surgery procedures. Category assigned by congenital heart surgery procedure (RACHS-1: 1–6; STAT: 1–5)
Pediatrics & Neonatology

Aristotle Basic Complexity Score

Complexity score for congenital heart surgery. Procedure-based score combining mortality, morbidity, technical difficulty
Pediatrics & Neonatology

Cardiac Z-score

Expresses an echo measurement as standard deviations from the mean for body size. z = (measured dimension − predicted mean for BSA) / SD
Pediatrics & Neonatology

Kawasaki Disease Coronary Classification (AHA)

Classifies coronary artery changes in Kawasaki disease from z-scores. Based on coronary z-score
Pediatrics & Neonatology

Pediatric Glasgow Coma Scale

Glasgow Coma Scale adapted for preverbal children. Eye (1–4), verbal (age-adapted, 1–5), motor (1–6)
Pediatrics & Neonatology

PECARN Head Injury Rule

Identifies children with head trauma at very low risk who can avoid CT. Age-specific (<2 y / ≥2 y) criteria: GCS, AMS, skull fracture signs, LOC, mechanism, vomiting, headache, behavior
Pediatrics & Neonatology

Neonatal Growth Percentile (Fenton / INTERGROWTH-21st)

Growth charts for preterm and newborn infants. Weight/length/HC plotted on Fenton (preterm) or INTERGROWTH-21st charts
Pediatrics & Neonatology

Developmental Quotient

Developmental age as a percentage of chronological age. DQ = developmental age / chronological (corrected) age × 100
Pediatrics & Neonatology

Head Circumference Growth (infant)

Expected head growth in infancy. ~2 cm/mo first 3 mo, 1 cm/mo 4–6 mo, 0.5 cm/mo 7–12 mo
Pediatrics & Neonatology

IMCI/WHO Danger Signs

WHO danger signs that need urgent referral in sick children. Unable to drink/breastfeed, vomits everything, convulsions, lethargic/unconscious
Obstetrics & Gynecology

Estimated Due Date (Naegele's Rule)

Estimated due date from the last menstrual period (Naegele). EDD = LMP + 1 year − 3 months + 7 days (= LMP + 280 days)
Obstetrics & Gynecology

Gestational Age from LMP

Gestational age in weeks and days from the last menstrual period. GA = (today − LMP date) / 7
Obstetrics & Gynecology

Gestational Age from CRL (Robinson)

Gestational age from first-trimester crown–rump length (most accurate dating). GA (days) = 8.052 × √CRL(mm) + 23.73
Obstetrics & Gynecology

Estimated Fetal Weight (Hadlock 4)

Estimated fetal weight from ultrasound biometry (Hadlock). log10 EFW = 1.3596 − 0.00386 AC×FL + 0.0064 HC + 0.00061 BPD×AC + 0.0424 AC + 0.174 FL
Obstetrics & Gynecology

Amniotic Fluid Index (AFI)

Amniotic fluid volume from four ultrasound pockets. Sum of deepest vertical pocket in 4 quadrants
Obstetrics & Gynecology

Bishop Score

Assesses cervical readiness for induction of labour. Dilation, effacement, station, consistency, position (0–3 / 0–2)
Obstetrics & Gynecology

Umbilical Artery Pulsatility Index

Umbilical artery Doppler indices; assess placental resistance. PI = (PSV − EDV) / mean velocity; S/D ratio = PSV/EDV
Obstetrics & Gynecology

Cerebroplacental Ratio

Ratio of MCA to umbilical artery PI; detects fetal brain-sparing. CPR = MCA PI / UA PI
Obstetrics & Gynecology

MCA PSV for Fetal Anemia

MCA peak velocity for detecting fetal anaemia. MCA peak systolic velocity in MoM for gestational age
Obstetrics & Gynecology

Kleihauer–Betke Anti-D Dose

Estimates fetomaternal haemorrhage and the anti-D dose needed. Fetal bleed (mL) = % fetal cells × 50 (maternal blood vol 5000 mL); vials = bleed / 30
Obstetrics & Gynecology

Postpartum Hemorrhage Estimated Blood Loss

Definition and early recognition of postpartum haemorrhage. PPH ≥1000 mL (any route) or with signs of hypovolemia; shock index >0.9
Obstetrics & Gynecology

sFlt-1/PlGF Ratio

Angiogenic marker ratio for predicting or ruling out pre-eclampsia. Ratio = sFlt-1 / PlGF
Obstetrics & Gynecology

Recommended Gestational Weight Gain (IOM)

Recommended pregnancy weight gain by pre-pregnancy BMI. By pre-pregnancy BMI
Obstetrics & Gynecology

Magnesium Sulfate (pre-eclampsia)

Magnesium sulfate regimen for severe pre-eclampsia and eclampsia. Loading 4–6 g IV over 15–20 min, then 1–2 g/h
Obstetrics & Gynecology

Ovarian Reserve – Antral Follicle Count

Ultrasound count of small follicles; estimates ovarian reserve. Sum of 2–10 mm follicles both ovaries
Obstetrics & Gynecology

Menstrual Cycle Ovulation Day

Estimated ovulation day from cycle length. Ovulation ≈ cycle length − 14
Hematology & Coagulation

Mean Corpuscular Volume (MCV)

Average red-cell size; classifies anaemia as micro-, normo- or macrocytic. MCV = Hct (%) × 10 / RBC (10⁶/µL)
Hematology & Coagulation

Mean Corpuscular Hemoglobin (MCH)

Average haemoglobin per red cell. MCH = Hb (g/dL) × 10 / RBC (10⁶/µL)
Hematology & Coagulation

MCHC

Haemoglobin concentration in red cells; high in spherocytosis. MCHC = Hb (g/dL) / Hct (%) × 100
Hematology & Coagulation

Mentzer Index

Helps separate thalassaemia trait from iron deficiency. MI = MCV / RBC count
Hematology & Coagulation

Reticulocyte Index (Corrected Retic)

Reticulocyte count corrected for the degree of anaemia. Corrected retic % = retic % × (Hct / 45)
Hematology & Coagulation

Reticulocyte Production Index (RPI)

Reticulocyte production index; tells whether the marrow is responding to anaemia. RPI = corrected retic % / maturation factor (1.0 Hct 45; 1.5 Hct 35; 2.0 Hct 25; 2.5 Hct 15)
Hematology & Coagulation

Transferrin Saturation

Percentage of transferrin carrying iron; low in iron deficiency, high in overload. TSAT = serum iron / TIBC × 100
Hematology & Coagulation

Estimated Blood Volume

Estimated circulating blood volume. EBV = weight × mL/kg (adult M 70–75, F 65; child 70–80; infant 80–85; neonate 85–90)
Hematology & Coagulation

Maximum Allowable Blood Loss

Blood loss tolerated before transfusion reaches a target haematocrit. MABL = EBV × (Hct initial − Hct target) / Hct average
Hematology & Coagulation

Expected Hb Rise per PRBC (adult)

Expected haemoglobin rise per red-cell unit in adults. 1 unit PRBC ≈ +1 g/dL Hb (+3% Hct)
Hematology & Coagulation

Corrected Count Increment (platelets)

Platelet response adjusted for body size; identifies refractoriness. CCI = (post − pre platelet count ×10⁹/L) × BSA (m²) / platelets transfused (×10¹¹)
Hematology & Coagulation

International Normalized Ratio

Standardises the prothrombin time across laboratories. INR = (PT patient / PT mean normal)^ISI
Hematology & Coagulation

4Ts Score (HIT)

Pre-test probability of heparin-induced thrombocytopenia. Thrombocytopenia, timing, thrombosis, other causes (0–2 each)
Hematology & Coagulation

ISTH DIC Score

Diagnoses overt disseminated intravascular coagulation (ISTH). Platelets, D-dimer/FDP, PT prolongation, fibrinogen
Hematology & Coagulation

PLASMIC Score (TTP)

Predicts severe ADAMTS13 deficiency (TTP) in thrombotic microangiopathy. Platelets <30, hemolysis, no cancer, no transplant, MCV <90, INR <1.5, Cr <2.0 (1 each)
Hematology & Coagulation

Caprini VTE Risk Score

VTE risk in surgical patients (Caprini). Weighted points for age, surgery type, history, risk factors
Hematology & Coagulation

Padua Prediction Score

VTE risk in medical inpatients; guides thromboprophylaxis. Cancer, prior VTE, reduced mobility, thrombophilia (3 each) + others
Hepatology & Gastroenterology

MELD Score

Predicts 3-month mortality in end-stage liver disease. MELD = 3.78 ln(bilirubin) + 11.2 ln(INR) + 9.57 ln(creatinine) + 6.43
Hepatology & Gastroenterology

MELD-Na

MELD with sodium; better prediction of mortality on the transplant list. MELD-Na = MELD + 1.32 × (137 − Na) − [0.033 × MELD × (137 − Na)]
Hepatology & Gastroenterology

MELD 3.0

Updated MELD adding sex and albumin. Adds sex, albumin and interaction terms to MELD-Na
Hepatology & Gastroenterology

PELD Score (pediatric <12 y)

Liver disease severity in children under 12 (PELD). 0.436 (age <1 y) − 0.687 ln(albumin) + 0.480 ln(bilirubin) + 1.857 ln(INR) + 0.667 (growth failure)
Hepatology & Gastroenterology

Child–Pugh Score

Classifies severity of cirrhosis. Bilirubin, albumin, INR, ascites, encephalopathy (1–3 each)
Hepatology & Gastroenterology

FIB-4 Index

Non-invasive marker of advanced liver fibrosis. FIB-4 = (age × AST) / (platelets ×10⁹/L × √ALT)
Hepatology & Gastroenterology

APRI

AST-to-platelet ratio; non-invasive marker of fibrosis. APRI = (AST/ULN) / platelets (×10⁹/L) × 100
Hepatology & Gastroenterology

NAFLD Fibrosis Score

Non-invasive fibrosis score for fatty liver disease. −1.675 + 0.037×age + 0.094×BMI + 1.13×IFG/DM + 0.99×AST/ALT − 0.013×platelets − 0.66×albumin
Hepatology & Gastroenterology

De Ritis Ratio

AST/ALT ratio; >2 suggests alcohol-related liver disease. AST / ALT
Hepatology & Gastroenterology

R-Factor (drug-induced liver injury)

Classifies drug-induced liver injury as hepatocellular, cholestatic or mixed. R = (ALT/ULN) / (ALP/ULN)
Hepatology & Gastroenterology

Maddrey Discriminant Function

Severity of alcoholic hepatitis; ≥32 suggests benefit from corticosteroids. DF = 4.6 × (PT patient − PT control) + bilirubin (mg/dL)
Hepatology & Gastroenterology

Serum–Ascites Albumin Gradient (SAAG)

Serum-ascites albumin gradient; identifies portal hypertension as the cause of ascites. SAAG = serum albumin − ascitic albumin
Hepatology & Gastroenterology

Ascitic PMN Count (SBP)

Ascitic neutrophil count; ≥250 diagnoses spontaneous bacterial peritonitis. PMN = ascitic WBC × % neutrophils
Hepatology & Gastroenterology

Albumin Dose After Paracentesis

Albumin replacement after large-volume paracentesis. 6–8 g albumin per liter removed (if >5 L)
Hepatology & Gastroenterology

Ranson's Criteria (pancreatitis)

Severity of acute pancreatitis at admission and 48 hours. 5 at admission + 6 at 48 h
Hepatology & Gastroenterology

BISAP Score

Early mortality risk in acute pancreatitis (BISAP). BUN >25, impaired mental status, SIRS, age >60, pleural effusion
Endocrinology & Diabetes

HOMA-IR

Estimates insulin resistance from fasting insulin and glucose. HOMA-IR = fasting insulin (µU/mL) × fasting glucose (mg/dL) / 405
Endocrinology & Diabetes

HOMA-β

Estimates beta-cell function from fasting insulin and glucose. HOMA-β = 360 × insulin / (glucose mg/dL − 63)
Endocrinology & Diabetes

Estimated Average Glucose from HbA1c

Converts HbA1c into average glucose. eAG (mg/dL) = 28.7 × HbA1c − 46.7
Endocrinology & Diabetes

HbA1c Unit Conversion

Converts HbA1c between % (NGSP) and mmol/mol (IFCC). IFCC (mmol/mol) = (NGSP % − 2.15) × 10.929
Endocrinology & Diabetes

Total Daily Insulin Dose

Starting total daily insulin dose by weight. TDD ≈ 0.5 U/kg/day (0.3 elderly/renal; 0.7–1.0 insulin resistant; children 0.7–1.0)
Endocrinology & Diabetes

Insulin Sensitivity (Correction) Factor

Expected glucose fall per unit of rapid-acting insulin. ISF = 1800 / TDD (mg/dL) or 100 / TDD (mmol/L)
Endocrinology & Diabetes

Insulin-to-Carbohydrate Ratio

Grams of carbohydrate covered by one unit of insulin. ICR = 500 / TDD
Endocrinology & Diabetes

DKA Severity (ADA)

Grades diabetic ketoacidosis severity. pH and HCO3 with glucose >250 and ketones
Endocrinology & Diabetes

Free Androgen Index

Free androgen index; assesses hyperandrogenism (e.g. PCOS). FAI = total testosterone (nmol/L) / SHBG (nmol/L) × 100
Endocrinology & Diabetes

Aldosterone-to-Renin Ratio

Screens for primary aldosteronism in hypertension. ARR = plasma aldosterone (ng/dL) / plasma renin activity (ng/mL/h)
Endocrinology & Diabetes

Free T4 Unit Conversion

Converts free T4 units. FT4 ng/dL × 12.87 = pmol/L
Neurology

Glasgow Coma Scale (adult)

Standard assessment of consciousness after injury or illness. Eye 1–4 + Verbal 1–5 + Motor 1–6
Neurology

FOUR Score

Coma score that adds brainstem reflexes and breathing (FOUR). Eye, motor, brainstem reflexes, respiration (0–4 each)
Neurology

NIH Stroke Scale (NIHSS)

Quantifies stroke severity (NIHSS). 15 items: LOC, gaze, visual, facial, motor, ataxia, sensory, language, dysarthria, extinction
Neurology

ABCD² Score (TIA)

Risk of stroke in the 2 days after a TIA. Age ≥60, BP ≥140/90, clinical (weakness 2, speech 1), duration (≥60 min 2, 10–59 1), diabetes
Neurology

Modified Rankin Scale

Measures disability or dependence after stroke. 0 no symptoms → 6 death
Neurology

ICH Score

Predicts 30-day mortality in intracerebral haemorrhage. GCS (3–4: 2, 5–12: 1), volume ≥30 mL, IVH, infratentorial, age ≥80
Neurology

ICH Volume (ABC/2)

Estimates haematoma volume on CT (ABC/2). Volume = A × B × C / 2 (cm)
Neurology

Hunt and Hess Grade (SAH)

Grades clinical severity of subarachnoid haemorrhage. I asymptomatic/mild headache → V deep coma
Neurology

Modified Fisher Scale (SAH)

Predicts vasospasm risk after subarachnoid haemorrhage from CT. CT blood thickness and IVH
Trauma, Burns & Emergency

Total Body Surface Area Burned (Rule of 9s)

Estimates burned body surface area (rule of nines). Adult: head 9, each arm 9, anterior trunk 18, posterior trunk 18, each leg 18, perineum 1
Trauma, Burns & Emergency

Palmar Method

Estimates small or scattered burns using the patient's palm (≈1% TBSA). Patient's palm with fingers ≈ 1% TBSA
Trauma, Burns & Emergency

Parkland Formula

24-hour resuscitation fluid for major burns (Parkland). Fluid = 4 mL × weight (kg) × %TBSA (LR) over 24 h; half in first 8 h from time of burn
Trauma, Burns & Emergency

Modified Brooke / ABA Formula

Burn resuscitation fluid with lower starting volumes (Brooke / ABA). Adults 2 mL × kg × %TBSA; children 3 mL × kg × %TBSA (+ maintenance <30 kg)
Trauma, Burns & Emergency

Galveston Formula (pediatric)

Burn resuscitation for children based on body surface area (Galveston). 5000 mL/m² burned + 2000 mL/m² total BSA per 24 h
Trauma, Burns & Emergency

Revised Baux Score

Predicts mortality after burns (revised Baux). Age + %TBSA + 17 (if inhalation injury)
Trauma, Burns & Emergency

Revised Trauma Score

Physiological triage score after trauma. RTS = 0.9368 × GCS code + 0.7326 × SBP code + 0.2908 × RR code
Trauma, Burns & Emergency

Injury Severity Score (ISS)

Anatomical severity score for multiple injuries. ISS = sum of squares of highest AIS in 3 most severely injured body regions
Trauma, Burns & Emergency

Canadian CT Head Rule

Identifies adults with minor head injury who need CT. High risk: GCS <15 at 2 h, open/depressed fracture, basal skull signs, ≥2 vomiting, age ≥65
Trauma, Burns & Emergency

Canadian C-Spine Rule / NEXUS

Identifies trauma patients who need cervical spine imaging. High-risk factors, low-risk factors, active rotation 45°
Trauma, Burns & Emergency

Ottawa Ankle Rules

Identifies ankle and foot injuries that need an X-ray. Bone tenderness at posterior malleolus/navicular/5th metatarsal base or inability to bear weight 4 steps
Trauma, Burns & Emergency

Heat Index / WBGT

Heat stress index for exercise and work safety. WBGT = 0.7 × wet bulb + 0.2 × globe + 0.1 × dry bulb (outdoor)
Epidemiology & Biostatistics

Sensitivity

Proportion of people with the disease who test positive. TP / (TP + FN)
Epidemiology & Biostatistics

Specificity

Proportion of people without the disease who test negative. TN / (TN + FP)
Epidemiology & Biostatistics

Positive Predictive Value

Probability of disease given a positive test (depends on prevalence). TP / (TP + FP)
Epidemiology & Biostatistics

Negative Predictive Value

Probability of no disease given a negative test (depends on prevalence). TN / (TN + FN)
Epidemiology & Biostatistics

Positive Likelihood Ratio

How much a positive test raises the odds of disease. LR+ = sensitivity / (1 − specificity)
Epidemiology & Biostatistics

Negative Likelihood Ratio

How much a negative test lowers the odds of disease. LR− = (1 − sensitivity) / specificity
Epidemiology & Biostatistics

Post-Test Probability (Bayes)

Post-test probability from pre-test probability and a likelihood ratio (Bayes). Post-test odds = pre-test odds × LR; odds = p/(1−p); p = odds/(1+odds)
Epidemiology & Biostatistics

Accuracy

Proportion of all test results that are correct. (TP + TN) / total
Epidemiology & Biostatistics

Youden's Index

Overall test performance; chooses the best cut-off on a ROC curve. J = sensitivity + specificity − 1
Epidemiology & Biostatistics

Relative Risk

Risk in the exposed relative to the unexposed (cohort studies, trials). RR = [a/(a+b)] / [c/(c+d)]
Epidemiology & Biostatistics

Odds Ratio

Odds of the outcome in exposed vs unexposed (case–control studies, logistic regression). OR = (a × d) / (b × c)
Epidemiology & Biostatistics

Absolute Risk Reduction

Absolute difference in event rates between control and treatment. ARR = CER − EER
Epidemiology & Biostatistics

Relative Risk Reduction

Proportional reduction in risk with treatment. RRR = (CER − EER) / CER = 1 − RR
Epidemiology & Biostatistics

Number Needed to Treat

Patients who need to be treated to prevent one extra event. NNT = 1 / ARR (round up)
Epidemiology & Biostatistics

Attributable Risk Percent

Proportion of disease in the exposed that is due to the exposure. AR% = (RR − 1) / RR × 100
Epidemiology & Biostatistics

Population Attributable Fraction

Proportion of disease in the population that is due to the exposure. PAF = Pe × (RR − 1) / [1 + Pe × (RR − 1)]
Epidemiology & Biostatistics

Incidence Rate

New cases per unit of person-time. New cases / person-time at risk
Epidemiology & Biostatistics

Prevalence

Proportion of a population with the condition at a given time. Existing cases / total population (≈ incidence × duration)
Epidemiology & Biostatistics

Case Fatality Rate

Proportion of cases who die from the disease. Deaths from disease / cases of disease × 100
Epidemiology & Biostatistics

Infant / Neonatal / Maternal Mortality

Infant, neonatal and maternal mortality rates. IMR = infant deaths / live births × 1000; NMR <28 d × 1000; MMR = maternal deaths / live births × 100,000
Epidemiology & Biostatistics

Standard Error of the Mean

Precision of a sample mean. SE = SD / √n
Epidemiology & Biostatistics

95% Confidence Interval (mean)

Range of plausible values for the population mean. Mean ± 1.96 × SE
Epidemiology & Biostatistics

95% CI for a Proportion (Wald)

Confidence interval for a proportion (Wald method). p ± 1.96 × √[p(1−p)/n]
Epidemiology & Biostatistics

Z-score (standard score)

Standard deviations a value lies from the mean. z = (x − mean) / SD
Epidemiology & Biostatistics

Coefficient of Variation

Spread relative to the mean; compares variability across scales. CV = SD / mean × 100
Epidemiology & Biostatistics

Sample Size – Single Proportion

Sample size to estimate a single proportion with a given precision. n = Z² × p(1 − p) / d²
Epidemiology & Biostatistics

Sample Size – Two Proportions

Sample size to compare two proportions. n per group = (Zα/2 + Zβ)² × [p1(1−p1) + p2(1−p2)] / (p1 − p2)²
Epidemiology & Biostatistics

Sample Size – Two Means

Sample size to compare two means. n per group = 2 × (Zα/2 + Zβ)² × SD² / Δ²
Epidemiology & Biostatistics

Cohen's Kappa

Agreement between two raters beyond chance. κ = (Po − Pe) / (1 − Pe)
Laboratory Conversions

Glucose mg/dL ↔ mmol/L

Converts glucose between mg/dL and mmol/L. mmol/L = mg/dL ÷ 18
Laboratory Conversions

Creatinine mg/dL ↔ µmol/L

Converts creatinine between mg/dL and µmol/L. µmol/L = mg/dL × 88.4
Laboratory Conversions

Urea / BUN Conversion

Converts BUN into urea. Urea (mmol/L) = BUN (mg/dL) ÷ 2.8; urea mg/dL = BUN × 2.14
Laboratory Conversions

Bilirubin mg/dL ↔ µmol/L

Converts bilirubin between mg/dL and µmol/L. µmol/L = mg/dL × 17.1
Laboratory Conversions

Cholesterol mg/dL ↔ mmol/L

Converts cholesterol and triglycerides between mg/dL and mmol/L. mmol/L = mg/dL ÷ 38.67 (triglycerides ÷ 88.57)
Laboratory Conversions

LDL Cholesterol (Friedewald)

Estimates LDL cholesterol from a standard lipid panel. LDL = TC − HDL − TG/5 (mg/dL) [TG/2.2 in mmol/L]
Laboratory Conversions

Non-HDL Cholesterol

Non-HDL cholesterol; includes all atherogenic lipoproteins. Non-HDL = TC − HDL
Laboratory Conversions

Calcium mg/dL ↔ mmol/L

Converts calcium between mg/dL and mmol/L. mmol/L = mg/dL ÷ 4.0
Laboratory Conversions

Milliequivalents from Milligrams

Converts milligrams of a salt into milliequivalents. mEq = mg × valence / molecular weight
Laboratory Conversions

Temperature Conversion

Converts temperature between °C and °F. °C = (°F − 32) × 5/9; °F = °C × 9/5 + 32
Laboratory Conversions

Weight & Length Conversion

Converts weight and length between metric and imperial units. kg = lb ÷ 2.2046; cm = inches × 2.54
Oncology

Calvert Formula (Carboplatin)

Carboplatin dose from target AUC and GFR (Calvert). Dose (mg) = target AUC × (GFR + 25)
Oncology

Absolute Neutrophil Nadir Timing

Expected timing of the neutrophil nadir after chemotherapy. Nadir typically 7–14 days post-chemotherapy
Oncology

MASCC Risk Index (febrile neutropenia)

Identifies low-risk febrile neutropenia suitable for outpatient care. Burden of illness, hypotension, COPD, solid tumor/no fungal infection, dehydration, outpatient, age <60
Oncology

ECOG Performance Status

Performance status in cancer care (ECOG). 0 fully active → 4 completely disabled; 5 dead
Oncology

Karnofsky Performance Status

Performance status in cancer care (Karnofsky). 100 normal → 0 dead (10-point steps)
Oncology

Tumor Lysis (Cairo–Bishop Lab Criteria)

Laboratory criteria for tumour lysis syndrome. ≥2 of: uric acid ≥8 mg/dL, K ≥6, PO4 ≥4.5 (adult)/≥6.5 (child), Ca ≤7 or 25% change
Geriatrics, Surgery & General Assessment

Timed Up and Go Test

Mobility and fall-risk test in older adults. Time to rise, walk 3 m, return and sit
Geriatrics, Surgery & General Assessment

FRAX (10-y fracture probability)

10-year fracture probability (FRAX). Age, sex, BMI, prior fracture, parental hip fracture, smoking, steroids, RA, secondary osteoporosis, alcohol, femoral neck BMD
Geriatrics, Surgery & General Assessment

T-score (DXA)

Bone density compared with a young adult; diagnoses osteoporosis. T = (patient BMD − young adult mean) / SD
Geriatrics, Surgery & General Assessment

Morse Fall Scale

Fall risk in hospital inpatients. History of falls, secondary diagnosis, ambulatory aid, IV, gait, mental status
Geriatrics, Surgery & General Assessment

Braden Scale (pressure injury)

Pressure-injury risk; lower scores mean higher risk. Sensory, moisture, activity, mobility, nutrition, friction/shear
Geriatrics, Surgery & General Assessment

Charlson Comorbidity Index

Predicts 10-year mortality from comorbidities. Weighted comorbidities (+ age points)
Geriatrics, Surgery & General Assessment

ASA Physical Status

Pre-operative physical status classification. I healthy → VI brain-dead donor; E for emergency
Geriatrics, Surgery & General Assessment

Clinical Frailty Scale

Frailty level in older adults (Rockwood). 1 very fit → 9 terminally ill
Geriatrics, Surgery & General Assessment

PHQ-9 (depression)

Screens for depression and grades its severity. 9 items scored 0–3
Geriatrics, Surgery & General Assessment

GAD-7 (anxiety)

Screens for generalised anxiety and grades its severity. 7 items scored 0–3
Geriatrics, Surgery & General Assessment

AUDIT-C (alcohol)

Short alcohol-use screen. 3 items scored 0–4

Reference values are typical adult ranges unless stated; labs, guidelines and local protocols vary. For education and research: verify against current guidelines before clinical use.

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