2. Selecting Optimal Positive End-Expiratory Pressure
- PEEP should be set in proportion to the current oxygen requirement
because hypoxemia is usually a reflection of ventilation–perfusion
mismatch due to atelectasis and low lung volume.
- Therefore, using a PEEP of 5 cm H2O for all infants with] (RDS) is not optimal
for oxygenation and lung recruitment.[1
- Using high PEEP may lead to lung hyperinflation, air leak, pneumothorax,
decrease cardiac venous return, as well as higher PaCO2 (as VT will be
lower)
- Using low PEEP may lead to lung hypo inflation, lung collapse, and increase
requirement for FiO2.
- We recommend starting with a PEEP of 5–6 cm H2O.
- PEEP should be increased gradually up to 8 cm H2O if the FiO2 is more than
0.30 and/or there is evidence of low lung volume on chest X-ray.
7. Potential benefits of PEEP and OLA ventilation in ARDS
“open lung strategy”
-maximises recruitment of alveoli (by preventing
de-recruitment)
-minimises cyclic atelectasis and atelectrauma
decreases biotrauma from alveolar collapse
(e.g. release of inflammatory mediators)
- minimises denitrogenation atelectasis and
oxygen toxicity (by allowing lower FiO2)
8.
9.
10. staircase recruitment manoeuvre
PEEP titration (adjust) (SRM)
Recruitment manoeuvres are used to open up
collapsed lung, and PEEP is used to prevent
cyclic collapse as part of OLA ventilation to:
increase end-expiratory lung volume
improve gas exchange
decrease VIL
11.
12. The open lung approach (OLA) to ventilation
Procedure
using pressure controlled ventilation adjust FiO2 to target SaO2 90-92%
set Pi to 15 cm H2O above the PEEP and maintain this difference
increase PEEP in a stepwise manner to 20, then 30 and then 40 cm H2O with
adjustments made every two minutes (i.e. Pi will reach 55 cmH20)
reduce PEEP to 25, then 22.5, then 20, then 17.5 or then an absolute
minimum of 15 cm H2O every three minutes until a decrease in SaO2 ≥ 1%
from maximum SaO2 is observed (the derecruitment point)
increase PEEP to 40 cm H2O for one minute then return to a PEEP level 2.5
cm H2O above the derecruitment point (the optimal PEEP)
then adjust to tidal volume ≤ 6 mls/kg IBW and a plateau pressure ≤ 30 cm
H2O, tolerate permissive hypercapnia if pH >7.15, can increase RR up to
38/min (max)
![Selecting Optimal Positive End-Expiratory Pressure
- PEEP should be set in proportion to the current oxygen requirement
because hypoxemia is usually a reflection of ventilation–perfusion
mismatch due to atelectasis and low lung volume.
- Therefore, using a PEEP of 5 cm H2O for all infants with] (RDS) is not optimal
for oxygenation and lung recruitment.[1
- Using high PEEP may lead to lung hyperinflation, air leak, pneumothorax,
decrease cardiac venous return, as well as higher PaCO2 (as VT will be
lower)
- Using low PEEP may lead to lung hypo inflation, lung collapse, and increase
requirement for FiO2.
- We recommend starting with a PEEP of 5–6 cm H2O.
- PEEP should be increased gradually up to 8 cm H2O if the FiO2 is more than
0.30 and/or there is evidence of low lung volume on chest X-ray.](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)