A recruitment breath manoeuvre directly after endotracheal suction improves lung function: an experimental study in pigs

Abstract

Background: Atelectasis occurs after a well performed endotracheal suction. Clinical studies have shown that recruitment manoeuvres added after endotracheal suction during mechanical ventilation restore lung function. Repetitive lung over-distension is, however, harmful for the lung, and the effects of adding a larger breath, recruitment breath, directly after repeated endotracheal suction were therefore investigated.

Methods: Twelve healthy anaesthetized pigs were randomized into two groups: one without and one with a recruitment breath manoeuvre (RBM), i.e. a breath 15 cmH(2)O above inspiratory pressure for 10 s during pressure-controlled ventilation. The pigs were suctioned every hour for 4 hours with an open suction system.

Results: At the end of the study there was a statistically significant difference between the group given RBM and that without with respect to PaCO(2), tidal volume (V(T)), and compliance (Crs). Without RBM, the PaCO(2) increased from 4.6+/-0.4 to 6.1+/-1.5 kPa, V(T) decreased from 345+/-39 to 247+/-71 mL, and Crs decreased from 28+/-6 to 18+/-5 mL/cmH(2)O. There was no change in PaCO(2) or Crs when a RBM was given. Morphological analysis revealed no differences in aeration of apical and central lung parenchyma. In the basal lung parenchyma there were, however, greater areas with normal lung parenchyma and less atelectasis after RBM.

Conclusions: Atelectasis created by endotracheal suction can be opened by inflating the lung for a short duration with low pressure, without over-distension, immediately after suction.

Figure 1.

Histological comparison of different pulmonary regions with (left column) and without (right column) recruitment breath manoeuvre (RBM). Zones 1–3 are presented from the top of the picture to the bottom. Note the slightly over-distended areas in zone 1 in both treatment groups and the difference in zone 3, with less aerated areas in lung specimens from a pig not treated with RBM.