Description of manual hyperinflation in intubated patients with atelectasis

Abstract

Physiotherapists propose that the use of manual hyperinflation in intubated patients reverses atelectasis and improves gas exchange. However, it is unclear whether physiotherapists apply the appropriate tidal volume and airway pressure required to achieve these benefits. The aims of this study were to measure and describe quantitatively the technique of manual hyperinflation applied to intubated patients with atelectasis and to determine the features of the patients' clinical presentation that alter the technique. Two physiotherapists manually hyperinflated 12 patients for 5 min each with a Laerdal (1.6L) resuscitation circuit. The tidal volume and inflation flow rate were measured by a Hans Rudolph pneumotachograph and the airway pressure and manual hyperinflation rate were measured by a Validyne DP45 low-pressure transducer. During manual hyperinflation, the physiotherapists applied a mean tidal volume of 973.8 ml, airway pressure of 32.7 cm H₂O and inflation flow rate of 713.8 ml/sec, with a manual hyperinflation rate of 9.1 breaths per minute. The patients' baseline tidal volume, minute ventilation and spontaneous respiratory effort led the physiotherapists to modify their technique significantly. Although we do not address the efficacy of the physiotherapy technique, the measurements obtained were clearly within the ranges that might be capable of reversing atelectasis and minimising the effects of suctioning without inducing barotrauma.