Background: Linear flow during cardiopulmonary bypass is considered a potential mechanism of lung damage in patients with chronic obstructive pulmonary disease (COPD). We evaluated differences in lung function of patients with COPD undergoing preoperative intraaortic balloon pumping (IABP), between linear flow during cardiopulmonary bypass (IABP-off) and maintenance of pulsatile flow (IABP-on at automatic 80 bpm) during cardioplegic arrest.
Methods: Fifty patients with COPD undergoing preoperative IABP were randomized between January 2004 and July 2005 to receive nonpulsatile cardiopulmonary bypass with IABP discontinued during cardioplegic arrest (25 patients; group A), or IABP-induced pulsatile cardiopulmonary bypass (25 patients; group B). Hospital outcome, need for noninvasive ventilation, oxygenation (partial pressure of oxygen, arterial to fraction of inspired oxygen [Pao(2)/Fio(2])), respiratory system compliance, and scoring of chest radiographs were compared.
Results: There were no hospital deaths, no IABP-related complications, and no differences in postoperative noninvasive ventilation (group A: 6 of 25, 24.0% vs group B: 5 of 25, 20%; p = not significant [NS]). One patient in both groups developed pneumonia (p = NS). Intensive care and hospital stay were comparable (p = NS). Group B showed lower intubation time (8.3 +/- 5.1 hours versus group A: 13.2 +/- 6.0; p = 0.001), better Pao(2)/Fio(2) at aortic declamping (369.5 +/- 93.7 mm Hg vs 225.7 +/- 99.3; p = 0.001) at admission in intensive care (321.3 +/- 96.9 vs 246.2 +/- 109.7; p = 0.003), and at 24 hours (349.8 +/- 100.4 vs 240.8 +/- 77.3; p = 0.003). The respiratory system compliance was better in group B at the end of surgery (56.4 +/- 8.2 mL/cm H(2)O vs 49.4 +/- 7.0; p = 0.004) and 8 hours postoperatively (76.4 +/- 8.2 vs 59.4 +/- 7.0; p = 0.0001), as well as scoring of chest radiograph at intensive care admission (0.20 +/- 0.41 vs 0.38 +/- 0.56; p = 0.05) and on the first day (0.26 +/- 0.45 vs 0.50 +/- 0.67; p = 0.025).
Conclusions: Automatic 80 bpm IABP during cardioplegic arrest preserves lung function in patients with COPD.