Respiratory normals

Question 1

Minute vent

Answer 1

Amt of air into lung per min(Vt•RR); +min vent =+wob

5-8L/min

Question 2

Dead space

Answer 2

~2mL/kg of Vt

Question 3

VQ ratio

Answer 3

Blood flow thru pulm cap membrane

(4Lvent/min [V]) / (5L perf/min [Q])= 0.8

Mismatch causes hypoxia on RA, is treated with O2, shunt is extreme mismatch needing PEEP

Question 4

PaO2

Answer 4

80-100

Question 5

SaO2

Answer 5

95-100%

% of Hgb carrying O2

Question 6

SvO2

Answer 6

60-75%

Best measure of perfusion at cell level

Question 7

CaO2

Answer 7

O2 content

15-20mL/100mL blood

Question 8

DO2

Answer 8

O2 delivery

900-1100mL/min

Question 9

VO2

Answer 9

O2 consumption at tissue level

250-360mL/min

Question 10

A-a Gradient

Answer 10

Alveolar arterial gradient

<10mmHg

Question 11

Vital Capacity

Answer 11

Amt of air exhaled after max inhale

60-70mL/kg

Question 12

Vt

Answer 12

Amount of air moves in and out of lungs in resp cycle

6-8mL/kg

5-6ml/kg best setting for ARDS patients

Question 13

Plateau Pressure

Answer 13

Pressure applied from vent on airway/alveoli

= or < 30cmH2O

Question 14

Peak Insp Pressure (PIP)

Answer 14

Highest pressure measured in resp cycle

> 50cmH20

Question 15

Static and Dynamic Compliance

Answer 15

Static-lung elasticity [(Vt/plateau p)-PEEP]

Dynamic-airway elasticity [(Vt/peak insp)-PEEP]

Both ~ 45-50mL/cmH2O

Question 16

Anion Gap

Answer 16

5-15mEq/L

Question 17

ETT placement

Answer 17

3-5cm above carina, cuff inflated to 20cmH20

Confirm with: waveform cap, CXR, ETCO2, and auscultation

Question 18

Vent mode: AC

Answer 18

Pt gets preset Vt at set RR, if pt breathes over will get preset Vt, all breaths are assisted with vent

full support

Question 19

Vent mode: SIMV

Answer 19

Pt gets set Vt at set RR, all extra breaths are pts own, vent syncs with pt effort

Full or partial support

Question 20

Vent mode: PSV

Answer 20

Pt triggers only, + airway pressure with i respiratory trigger to increase spontaneous Vt

Used for weaning, pt must not be paralyzed or sedate

Question 21

Vent mode: CPAP

Answer 21

continuous positive airway pressure, 0 machine breaths last step of weaning process

Question 22

Weaning: passing criteria

Answer 22

Spontaneous Vt > 5mL/kg
NIF > -25cmH20
Vital Capacity > 10mL/kg
Resting Minute Vent < 10
Rapid Shallow Breathing Index (RR/Vt) < 105
PaO2/FiO2 ratio > 150
No abnormal VS 
ABG is ok

Question 23

Weaning: failed/ stop trial

Answer 23

RR>35 or < 6 
SpO2 < 88%
VS acute changes
AMS
Resp Distress
Arrhythmias