24. Before Recruitment
Arterial blood gas 18:00 23/10/1999 Fi02=0.7
pH=7.47 pCO2=31 pO2=59 Saturation 91%
After Recruitment
Arterial blood gas 19:00 23/10/1999 Fi02=0.6
pH=7.45 pCO2=34 pO2=182 Saturation 99%
25. PEEP after recruitment
– Generally, it is recommended (Hickling 2001) to
gradually decrease PEEP until there is a fall in PO2; this is
a “decremental PEEP trial”
– PEEP is decreased by 2cmH2O every 4 minutes
– A fall in PO2 by over 10% indicates that there is
derecruitment
– PEEP is then set to just 2cmH2O above the level at which
derecruitment occurs
– For Girgis et al (2006) this strategy resulted in 4 hrs of
improved oxygenation
26. PEEP Endpoints
• Best PaO2
• Best O2 delivery
• Pplat < 30 cm H2o
• Best CT aeration
• The best possible lung compliance
• Hemodynamic stability
27.
28.
29. Protective Ventilation Strategy in ARDS
• Keep the PaO2 55-80 mmHg
• Maintain an arterial oxygen saturation (SaO2) of 88-94%
• Avoid volutrauma, barotraumas and biotrauma (VIL), by keeping the tidal volumes in the 4-6ml/kg
range and airway plateau pressure < 30 cmH2O .
• Predicted body weight in kg, calculated by: [2.3 *(height in inches - 60) + 45.5 for women or + 50
for men].
* PEEP values of 2cmH2O above PEEP associated with optimal compliance
• Higher respiratory rate.
• PH ≥ 7.15
31. Driving Pressure and Survival in the Acute Respiratory Distress Syndrome
The New England Journal of Medicine 2015
32. In patients with severe ARDS as defined by PaO2/FiO2 <150,
48 hrs administration of non depolarizing neuromuscular
blocking agent (NMBA) cisatracurium has been shown to
improve oxygenation, and adjusted 90-day survival, as well as
decreasing duration of mechanical ventilation and
barotrauma, without increasing muscle weakness .Moreover,
NMBAs have been shown to reduce levels of both pulmonary
and systemic pro-inflammatory mediators
Papazian L, Forel JM, Gacouin A, et al. Neuromuscular blockers in early acute
respiratory distress syndrome. N Engl J Med 2010;363:1107-16
35. Preparation
• Criteria
– PaO2/FiO2 ratio ≤ 150mmHg (20kPa)
– PEEP ≥ 5cmH2O
– FiO2 ≥ 0.6
• Haemodynamically stable
• Not severely acidaemic,
• Does not have intracranial hypertension
• Adequately paralysed
• Increase FiO2 to 1.0 app 15-20 min before repositioning
36. Duration
• Most responders show an improvement in gas
exchange within a few hours
• Prone for 16h then supine for at least 4h
39. Preparation
• Prepare padding to prevent pressure sores in
prone position
• Staff
• Someone who can re-intubate to look after head, neck
& ETT
• 4 other staff
40. Duration
• Most responders show an improvement in gas
exchange within a few hours
• Prone for 16h then supine for at least 4h
41. Prone positioning (face-down) improves gas exchange and has long been used as an
adjunctive or salvage therapy for severe or refractory ARDS. Prone positioning is
gaining credibility as a new standard of care for ARDS after a multicenter trial
published in 2013, demonstrated a dramatic near-50% relative risk reduction, and a
17% absolute risk reduction for mortality
42. Benefits of prone positioning
• Improves V/Q mismatch
• Increased ventilation in dependent areas
• Decreases physiologic shunt
• Improved ventilation in areas where perfusion remains the same
• Decreases compression/Increase FRC
Cardiac
Abdominal
• Prevent ventilator associated lung injury
• Enhances mobilization of secretions
43. Summary
• Low tidal volume, low pressure
• Open lung approach makes “sense”
– Recruitment
– High PEEP
• Minimize FiO2
• Early prone ventilation in patients meeting
criteria
