Effects of Manual Rib Cage Compressions on Mucus Clearance in Mechanically Ventilated Pigs.

BACKGROUND: Manual rib cage compression is a chest physiotherapy technique routinely used in clinical practice. However, scientific evidence remains scarce on the effects of manual rib cage compression on airway clearance and oxygenation in mechanically ventilated patients. METHODS: Anesthetized pigs were intubated via the trachea and mechanically ventilated. To create atelectasis, artificial mucus was infused into the airway. Each pig was randomly assigned to 1 of 2 groups: closed suctioning alone (control group, 7 pigs), or manual rib cage compression combined with closed suctioning (manual rib cage compression group, 8 pigs). Hard and brief rib cage compression synchronized with early expiratory phase was tested. Mucus clearance and oxygenation were assessed after the intervention. Sequential changes of hemodynamics were assessed after the intervention. RESULTS: During hard manual rib cage compression, the mean +/- SD peak expiratory flow increased to 44 +/- 7 L/min compared with 31 +/- 7 L/min without treatment (P < .001). Manual rib cage compression combined with endotracheal suctioning increased mucus clearance compared with closed suctioning alone (mucus amounts, 5.5 [3.4-9.4] g vs 0.7 [0.5-2.0] g; P = .004); however, it did not improve gas exchange and radiologic findings. There were no significant differences in hemodynamic variables between the 2 groups. CONCLUSIONS: Our findings indicated that hard and brief manual rib cage compression combined with closed suctioning was safe and led to improvement of mucus clearance; however, no effectiveness was confirmed with regard to oxygenation and ventilation.