APEX-ANS EXAM QUESTIONS AND
CORRECT ANSWERS 2026 LATEST
PREP GUIDE VERIFIED A+
◉ Treatment for methemaglobinemia.
Answer: IV methylene blue 1-2mg/kg
◉ Methemaglobinemia effect on P50 and oxyHGB dissociation curve.
Answer: Shifts to the left
Decreases P50
◉ Bohr effect.
Answer: Why hemoglobin releases oxygen at the tissue level and binds
oxygen in the lungs
◉ Haldane effect.
Answer: Deoxygenation of the blood (low PO2) increases its ability to
carry carbon dioxide
◉ Hering-Breuer reflex.
Answer: A protective mechanism that terminates inhalation, thus
preventing overexpansion of the lungs.
◉ J receptor stim.
,Answer: Causes tachyonea when there is a pulmonary embolism
◉ When does hypoxic vasoconstriction reach peak effect.
Answer: 15 minutes
◉ DO2 equation.
Answer: CO X (Hgb x SaO2 x 1.34) + (PaO2 X .003) x 10
◉ Ca02 equation.
Answer: (Hb x 1.34 x Sa02) + (Pa02 x 0.003)
◉ Normal DO2 (oxygen delivery).
Answer: 1000 mL/min
◉ Normal CaO2 (Arterial Oxygen content/O2 carrying capacity).
Answer: 20mL/O2/dL
◉ Alveolar gas equation.
Answer: PaO2 = FiO2 x (Patm - Pwater vapor) - (PaCo2 / RQ)
RQ = 0.8
Patm = 760
PH2O = 47
,◉ Normal O2 extraction ration.
Answer: 25%
◉ VO2 formula.
Answer: CO x (CaO2 - CvO2) x 10
◉ Normal CvO2 (Venous Oxygen Content).
Answer: 15 mL/dL
◉ Formula to predict paO2 by age.
Answer: 100 - (age x .4)
◉ Static compliance equation.
Answer: Tidal volume/(plateau pressure - PEEP)
◉ Dynamic Compliance Equation.
Answer: Vt / (Peak insp pressure - PEEP)
◉ Which utilized peak inspiratory pressure to calculate the value: static
compliance or dynamic compliance.
Answer: Dynamic
, ◉ A-a gradient equation.
Answer: PAO2 - PaO2
◉ Formula for calculating MAP from SBP and DBP.
Answer: SBP + DBPX2 Then divide that by 3
◉ SVR equation.
Answer: SVR = (MAP-CVP / CO) x 80
◉ Coronary Perfusion Pressure (CPP) formula.
Answer: DBP - LVEDP (or Pulm occlusion pressure)
◉ MABL formula.
Answer: EBV x (starting Hct - target HCT) / start HCT
◉ Poiseuille's Law.
Answer: Flow is directly proportional to radius and pressure difference
and inversely proportional to viscosity and tube length
◉ When does isovolumetric contraction occur?.
Answer: Early systole: after the mitral valve closes and before the aortic
valve opens - right before rapid ejection of SV
◉ After which valve closed does isovolumetric relaxation begin.
CORRECT ANSWERS 2026 LATEST
PREP GUIDE VERIFIED A+
◉ Treatment for methemaglobinemia.
Answer: IV methylene blue 1-2mg/kg
◉ Methemaglobinemia effect on P50 and oxyHGB dissociation curve.
Answer: Shifts to the left
Decreases P50
◉ Bohr effect.
Answer: Why hemoglobin releases oxygen at the tissue level and binds
oxygen in the lungs
◉ Haldane effect.
Answer: Deoxygenation of the blood (low PO2) increases its ability to
carry carbon dioxide
◉ Hering-Breuer reflex.
Answer: A protective mechanism that terminates inhalation, thus
preventing overexpansion of the lungs.
◉ J receptor stim.
,Answer: Causes tachyonea when there is a pulmonary embolism
◉ When does hypoxic vasoconstriction reach peak effect.
Answer: 15 minutes
◉ DO2 equation.
Answer: CO X (Hgb x SaO2 x 1.34) + (PaO2 X .003) x 10
◉ Ca02 equation.
Answer: (Hb x 1.34 x Sa02) + (Pa02 x 0.003)
◉ Normal DO2 (oxygen delivery).
Answer: 1000 mL/min
◉ Normal CaO2 (Arterial Oxygen content/O2 carrying capacity).
Answer: 20mL/O2/dL
◉ Alveolar gas equation.
Answer: PaO2 = FiO2 x (Patm - Pwater vapor) - (PaCo2 / RQ)
RQ = 0.8
Patm = 760
PH2O = 47
,◉ Normal O2 extraction ration.
Answer: 25%
◉ VO2 formula.
Answer: CO x (CaO2 - CvO2) x 10
◉ Normal CvO2 (Venous Oxygen Content).
Answer: 15 mL/dL
◉ Formula to predict paO2 by age.
Answer: 100 - (age x .4)
◉ Static compliance equation.
Answer: Tidal volume/(plateau pressure - PEEP)
◉ Dynamic Compliance Equation.
Answer: Vt / (Peak insp pressure - PEEP)
◉ Which utilized peak inspiratory pressure to calculate the value: static
compliance or dynamic compliance.
Answer: Dynamic
, ◉ A-a gradient equation.
Answer: PAO2 - PaO2
◉ Formula for calculating MAP from SBP and DBP.
Answer: SBP + DBPX2 Then divide that by 3
◉ SVR equation.
Answer: SVR = (MAP-CVP / CO) x 80
◉ Coronary Perfusion Pressure (CPP) formula.
Answer: DBP - LVEDP (or Pulm occlusion pressure)
◉ MABL formula.
Answer: EBV x (starting Hct - target HCT) / start HCT
◉ Poiseuille's Law.
Answer: Flow is directly proportional to radius and pressure difference
and inversely proportional to viscosity and tube length
◉ When does isovolumetric contraction occur?.
Answer: Early systole: after the mitral valve closes and before the aortic
valve opens - right before rapid ejection of SV
◉ After which valve closed does isovolumetric relaxation begin.
