Resp Physiology

Question 1

oxygen hemoglobin dissociation curve

Answer 1

cooperative binding properties
x-axis = PaO2 mmHg
y-axis = SpO2 %
Right shift = high H+, temp, CO2, 2,3-BPG
Left shift = low H+, temp, CO2, 2,3-BPG

Question 2

Quick chart for PaO2 and SpO2

Answer 2

PaO2 - 40, 50, 60

SpO2 - 70, 80, 90

Question 3

V/Q approaches infinity

Answer 3

Dead space (no perfusion)
PE, cardiac arrest, anatomic dead space
- retain CO2 and decrease elimination
*look sleepy and flushed

Question 4

V/Q approaches zero

Answer 4

Shunt (no ventilation)
PTX, pneumonia, airway obstruction
- hypoxic
*look anxious, clammy, cyanotic

Question 5

Alveolar Gas Equation

Answer 5

PAO2 = FiO2 - (PaCO2)/RER

PAO2 - PaO2 = V/Q ~ 8-10

Question 6

Oxygen Content Equation

Answer 6

CaO2 = PaO2 + (Hgb)(SpO2)

Question 7

O2 delivery

Answer 7

CaO2 x CO

Question 8

Lung volumes

Answer 8

TV = 600 mL
ERV = 1200 mL
RV = 1200 mL
IRV = 3000 mL
TLC = 6 L
FRC = 2400 mL

Question 9

Why pre-oxygenate?

Answer 9

if you fill the entire FRC (2400 mL) with 100% O2, that is a long time (8-10 min) that they can go without breathing

Question 10

CMV

Answer 10

constant mandatory ventilation

either VC or PC

Question 11

VC

Answer 11

fixed TV and RR (possible barotrauma)

Question 12

PC

Answer 12

fixed pressure and RR (uncomfortable)

Question 13

AC

Answer 13

assist control - delivers fixed TV or pressure with each triggered breath
- every breath is supported by ventilator => can lead to hyperventilation

Question 14

SIMV

Answer 14

spontaneous intermittent mandatory ventilation

- synced to breathing -> if no breaths, switches to assist control

Question 15

PS

Answer 15

pressure support - augments spontaneous breathing

-> triggered by breaths (good for weaning)

Question 16

PRVC

Answer 16

pressure-regulated volume control -> set a minimum RR, TV, and pressure limits

• > vent adjusts pressure from breath to breath
• less barotrauma