PEEP

Question 1

Define PEEP

Answer 1

Positive pressure that remains in the airways after expiration, that is greater than atmospheric pressure (760mmHg, 0cm H2O).

Question 2

List the 3 primary benefits of PEEP.

Answer 2

1. Improve oxygenation
2. Improve VQ mismatch
3. Decrease WOB

Question 3

How does PEEP improve oxygenation? (3)

Answer 3

Increases O2 solubility against pressure gradient. (Henry’s Law)

Recruits/inflates alveoli which increases SA for gas exchange.

May redistribute EVLW to peribronchial interstitium, which improves O2 diffusion.

Question 4

How does PEEP improve VQ mismatch? (1)

Answer 4

Opens and splints airways which decreases atelectasis and increases alveolar recruitment - increasing ventilation of previously collapsed but still perfusing alveoli.

Question 5

How does PEEP improve WOB? (3)

Answer 5

1. Improves compliance by maintaining pressure (less effort to add volume than to fully re-inflate alveoli)
2. Opens dead space down to small bronchi level, reduces turbulence, resistance and improves laminar flow
3. Prevents cyclic de-recruitment on expiration which decreases atelectrauma, VILI and biotrauma from collapse.

Question 6

List 7 potential adverse effects of PEEP.

Answer 6

1. Impaired CO2 clearance
2. Barotrauma
3. Exacerbate pulmonary shunt
4. Increased ITP on right heart = hypotension
5. Increased pulmonary vascular resistance
6. Exacerbate R to L intracardiac shunts
7. Increased ICP

Question 7

List the CWI indications for PEEP.

Answer 7

1. All patients receiving IPPV with cardiac output
2. All neonates receiving IPPV

Question 8

List the CWI contraindications for PEEP.

Answer 8

1. Adults/paeds in cardiac arrest
   (still indicated in neonatal arrest)

Question 9

List the CWI precautions for PEEP.

Answer 9

1. Hypovolaemia/severe hypotension
2. Tension pneumothorax
3. Elevated ICP
4. Right ventricular failure

Question 10

What is the recommended PEEP setting for mechanically ventilated patients with OBSTRUCTIVE lung pathology?

Answer 10

<5cmH2O

Question 11

What is the recommended PEEP setting for mechanically ventilated patients with RESTRICTIVE lung pathology?

Answer 11

5 - 15 cmH2O

Question 12

What is the recommended PEEP setting for mechanically ventilated patients with normal lungs?

Answer 12

5cmH2O

Question 13

What is the recommended PEEP for neonatal resuscitation?

Answer 13

5cmH2O

Question 14

What is the recommended PEEP for adults in cardiac arrest?

Answer 14

ZEEP.

Question 15

What is the recommended PEEP for paediatric patients?

Answer 15

5cm H2O