Tuesday February 26, 2008
Effect of PEEP on the incidence of aspiration in mechanically ventilated patients

See this interesting study to test the effects of PEEP (positive end expiratory pressure) on the leakage of fluid around cuffs of different tracheal tubes, in mechanically ventilated patients and in a benchtop model.

Patients: 40 patients recovering in the intensive care unit distributed in 2 groupswith 2 different types of ETT Hi-Lo tubes and SealGuard tubes (SG group)

Interventions: Following steps applied

1. Immediately after intubation and cuff inflation with 30 cm H2O, Evans blue was applied onto the cephalic surface of the tracheal tube cuff
2. A 5-cm H2O positive expiratory pressure was used during the first 5 hrs of stay, and thereafter it was removed
3. Leakage was also tested in vitro with the same tracheal tubes with incremental level of PEEP
4. At 1 hr, 5 hrs, and thereafter hourly until 12 hrs, bronchoscopy was used to test the presence of dye on the trachea caudal to the cuff

Results:

• At the fifth hour, two patients of the HL group failed the test
• One hour after positive expiratory pressure removal, all subjects in group HL exhibited a dyed lower trachea
• One patient in group SG presented a leak at the eighth hour, and at the 12th hour 17 had leak
• In vitro, the same level of PEEP delayed the passage of dye
  
  

Conclusions: Authors concluded that 5 cm H2O positive expiratory pressure was effective in delaying the passage of fluid around the cuffs of tracheal tubes both in vivo and in vitro.

Reference: click to abstract / article

Effect of positive expiratory pressure and type of tracheal cuff on the incidence of aspiration in mechanically ventilated patients in an intensive care unit , Critical Care Medicine. 36(2):409-413, February 2008