Warfarin Dose Adjustment Calculator (INR Nomogram)

Calculate the alveolar-arterial O₂ gradient to distinguish hypoxemia causes. PAO₂ = FiO₂×(P_atm−47) − PaCO₂/0.8; A-a = PAO₂ − PaO₂. Normal ≈ (Age+10)/4. Elevated → V/Q mismatch, shunt, diffusion impairment. Derived from StatPearls, LITFL, Cornell PICU, and Martin 1999. Not medical advice.

Calculate PAO₂ = FiO₂ × (P_atm − 47) − PaCO₂ / RQ. Defaults: P_atm 760 mmHg (sea level), RQ 0.8. Gives a directional hint vs expected ~100 mmHg. For full A-a gradient interpretation use a-a-gradient-calculator. Derived from StatPearls, LITFL, Cornell PICU, and West. Not medical advice.

Calculate VA = (VT − VD) × RR in L/min. VD may be supplied or estimated as ~2 mL/kg body weight. Normal resting ~4–6 L/min; low → hypercapnia, high → hypocapnia. Derived from West, LITFL, StatPearls, and Radford 1955. Not medical advice.

Calculate the Apgar score to assess newborn condition at 1 minute and 5 minutes after birth. Five signs are each scored 0–2 at both time points: Appearance (skin color), Pulse (heart rate), Grimace (reflex irritability), Activity (muscle tone), and Respiration. Each time point totals 0–10. Interpretation: 7–10 reassuring; 4–6 moderately abnormal (may need assistance); 0–3 critically low (immediate resuscitation). The tool reports both the 1-min and 5-min scores, the change (delta), and per-time-point interpretation. A 5-min score, and especially the change from 1 to 5 min, indicates response to resuscitation; persistent low 5-min scores warrant continued resuscitation and reassessment at 10 min. Derived from Apgar 1953, reaffirmed by ACOG/AAP. The Apgar is a physiologic snapshot at a moment in time and is not, by itself, a marker of asphyxia or long-term neurologic outcome. Not medical advice.