Friday November 4, 2005
Prone positioning target - O2 or PCO2 ?
Literature on prone postioning in ARDS is not encouraging4 but as Dr. Alain F. Broccard showed optimism by saying: "Are We Looking at a Half-Empty or Half-Full Glass?" (ref. 2).
Dr. Gattinoni's 2001 NEJM article (ref. 3) failed to show any benefit on survival despite improved oxygenation but 2 years later his article in Critical Care Medicine Journal (Ref. 1) found that ARDS patients who respond to prone positioning with reduction of their Paco2 show an increased survival at 28 days. Improved efficiency of alveolar ventilation (decreased physiologic deadspace ratio) has been concluded as an important marker of patients who will survive acute respiratory failure.
So the Question is: In prone positioning should we target improve oxygenation or decreasing Paco2 ????
Refrences: click on link to get article/abstract
1. Decrease in Paco2 with prone position is predictive of improved outcome in acute respiratory distress syndrome - Crit Care Med 31(12):2727-2733, 2003
2. Prone Position in ARDS Are We Looking at a Half-Empty or Half-Full Glass? - (Chest. 2003;123:1334-1336.)
3. .Effect of Prone Positioning on the Survival of Patients with Acute Respiratory Failure - NEJM, Aug. 2001- Volume 345:568-573
4. Effects of Systematic Prone Positioning in Hypoxemic Acute Respiratory Failure - JAMA - Vol. 292 No. 19, November 17, 2004