3. Early pathologic features of ARDS
ā¢ Diffuse alveolar damage (DAD)
ā¢ There is minimal alveolar septal thickening,
hyperplasia of pneumocytes
ā¢ Eosinophilic hyaline membranes present
15. CT scan showed Severe surgical emphysema and pneumomediasteum
16.
17.
18.
19. Diseased Lungs Do
Not Fully Collapse,
Despite Tension Pneumothorax
ā¦and
They cannot always
be fully āopenedā
Dimensions of a fully
Collapsed Normal Lung
21. Spectrum of Regional Opening Pressures
(Supine Position)
Superimposed
Pressure Inflated 0
Alveolar Collapse
(Reabsorption) 20-60 cmH2O
Small Airway
Collapse
10-20 cmH2O
Consolidation ļ„
Lung Units at Risk for Tidal
Opening & Closure
=
Opening
Pressure
22. How Much Collapse Depends on the Plateau
R = 100%
20
60
100
Pressure [cmH2O]
20 40 60
TotalLungCapacity[%]
R = 22%
R = 81%
R = 93%
0
0
R = 0%
R = 59%
Some potentially
recruitable units
open only at high
pressure
More Extensive
Collapse But
Lower PPLAT
Less Extensive
Collapse But
Greater PPLAT
25. Recruitment Maneuvers (RMs)
Proposed for improving
Arterial oxygenation
Enhancing alveolar recruitment
All consisting of short-lasting increases in
intrathoracic pressures
26. Recruitment Maneuvers (RMs)
āVital capacity maneuver
(inflation of the lungs up to 40 cm H2O,
maintained for 15 - 26 seconds)
āIntermittent sighs
āExtended sighs
27. Recruitment Maneuvers (RMs)
āIntermittent increase of PEEP
āContinuous positive airway pressure
(CPAP)
āIncreasing the ventilatory pressures to a
plateau pressure of 50 cm H2O for 1-2
minutes
28. Other manoeuvres
ā¢ Prone positioning ventilation
ā¢ Prolonged inspiration
ā¢ Inverse ratio ventilation
29. Limit of open lung strategy
ā¢ To minimise VILI
to the less damaged alveoli
Max insp pressure
(plateau pressure 30-32cm H20)
30. Limit of open lung strategy
Max pressure remains unchanged
TV will decrease
Alveolar ventilation will decrease
Alv V: dead space vent ratio
will decrease
31. Increasing PaCO2
ā¢ Management options
Increase resp rate
Minute
volume
Delivered TV TV ml/kg Resp rate
6.4 L 640 ml 8 10
6.4 L 480 ml 6 14
6.4 L 320 ml 4 20
6.4 L 160 ml 2 40
Anatomical dead space 150ml
35. ā¢ Inert
ā¢ No odor
ā¢ No color
ā¢ Low surface tension
ā¢ Carry large amount of O2 & CO2
Perfluorocarbon
(PFC)
36. Medication:
Morphine sulfate
(0.1mg/kg/dose), pavulon
(0.1 mg/kg/dose)
Rimar (30 ml/kg)
Ventilation settings:
Ti 5 sec, hold 10 sec, Te 5
sec (3-6 cycles/min)
CO2 eleminated by
increase tidal volume
O2 managed by change O2
content and FRC
37.
38. ON START OF GAS
VENTILATION
ONE HOUR AFTER
PLV
48 HOUR AFTER PLV 3 WEEKS AFTER PLV
Partial liquid ventilation with perflubron in premature infants with severe
respiratory distress syndrome