The effect of lung hyperinflation and endotracheal suctioning on cardiopulmonary hemodynamics.

The purpose of this study was to examine the effect of sequential lung hyperinflation breaths followed by suction on mean arterial pressure (MAP), cardiac output (CO), pulmonary artery pressure (PAP), and pulmonary airway pressure (Paw) to elucidate the mechanism for the increase in MAP seen with lung hyperinflation and suction. Thirty-four postoperative coronary artery bypass graft patients were randomly exposed to three lung hyperinflation breaths at one of five volumes (tidal volume, 12cc/kg, 14cc/kg, 16cc/kg, and 18cc/kg of lean body weight) using a ventilator followed by 10 s of suctioning repeated for a total of three times. There was a mean increase in MAP (13.71 torr), CO (12.2%), PAP (4 torr), and Paw (23.5 torr) above baseline over the three sequences. The mechanism for the increase in MAP with lung hyperinflation may be attributed to transient increases in intrathoracic pressure, resulting in increased left ventricular preload and CO.