Apex Pearls

Question 1

Minute Ventilation

Answer 1

tidal volume x respiratory rate

Question 2

Alveolar Ventilation

Answer 2

(tidal volume - dead space) x resp rate

Question 3

Alveolar Oxygen Equation

Answer 3

FiO2 x (Pb - H20) - (PaCO2 / RQ)
Pb = barometric pressure (usually 760 mmHg)
PH20 = humidity of inhaled gas (47)
RQ = resp quotient (assumed 0.8)

Question 4

CaO2 - Oxygen Content

Answer 4

(1. 34 x Hbg x SaO2) + (PaO2 x 0.003)

0. 003 = oxygen’s solubility coefficient

Question 5

What causes P50 to shift to the left?

Answer 5

Left = Love
DECREASED temp, 2,3 DPG, CO2, H+
INCREASED pH
Hgb met, CO, F

Question 6

Autonomic Hyperreflexia

Answer 6

classic: HTN and bradycardia
- activation of spinal reflexes below level of injury, causes vasoconstriction below level of injury, vasodilation above level of injury and reflex bradycardia

• an acute rise in svr can cause pulmonary edema