Increasing Pressure Support Does Not Enhance Secretion Clearance if Applied During Manual Chest Wall Vibration in Intubated Patients: a Randomised Trial

Questions: What is the effect of increasing pressure support during the application of manual chest wall compression with vibrations for secretion clearance in intubated patients in intensive care?

Design: A randomised trial with concealed allocation, assessor blinding and intention-to-treat analysis.

Participants: 66 patients receiving mechanical ventilation for greater than 48 hours.

Intervention: All participants were positioned supine in bed with the backrest elevated 30 degrees. The experimental group received manual chest wall compression with vibrations during which their pressure support ventilation was increased by 10 cm H(2)O over its existing level. The control group received manual chest wall compression with vibrations but no adjustment of the ventilator settings. Both groups then received airway suction.

Outcome Measures: The primary outcome was the weight of the aspirate. Secondary outcomes were pulmonary and haemodynamic measures and oxygenation.

Results: Although both treatments increased the weight of the aspirate compared to baseline, the addition of increased pressure support during manual chest wall compression with vibrations did not significantly increase the clearance of secretions, mean between-group difference in weight of the aspirate 0.4 g, 95% CI -0.5 to 1.4. Although several other measures also improved in one or both groups with treatment, there were no significant differences between the groups for any of the secondary outcomes.

Conclusion: Although increasing pressure support has previously been shown to increase secretion clearance in intubated patients, the current study did not show any benefits when it was added to chest wall compression with vibrations.

Trial Registration: NCT01155648.