ABSTRACT
In Off Pump Coronary Artery Bypass [OPCAB] surgery, there is a high incidence of deterioration in lung mechanics and arterial oxygenation. This study aimed at assessing the effect of alveolar recruitment on lung mechanics and oxygenation in patients undergoing OPCAB surgery. In this study, we performed a randomized controlled trial between 2 groups of patients undergoing OPCAB surgery. Group A: patients received a PEEP of 5 cm H20 only. Group 3: Alveolar Recruitment Strategy [ARS] was applied after finishing the proximal anastomotic procedure and repeated in the postoperative period in the ICU. The ARS consisted of raising the peak inspiratory Pressure [PIP] to 30 cm H20 and setting PEEP at 10 cm H20 and maintaining them for 1 minute. Then, both PIP and PEEP were increased to 40 and 15 cm H20 respectively and maintained for another minute. After arrival to the ICU, all patients received 5 cm H20 PEEP, then after 1 hour, the patients received either PEEP only or with the same previous strategy as in O.R. to their groups. In the OR, lung compliance as well as arterial oxygenation were measured after induction of anesthesia, before, and after setting both PEEP and ARS. In the ICU, arterial oxygenation was measured before both PEEP and ARS, as well as one and four hours later. Postoperative pulmonary complications including hypoxemia, hypercapnia, atelectasis, prolonged intubation, pulmonary congestion, pulmonary infection, total ICU stay and mortality werq recorded. There was a significant rise in lung compliance and arterial oxygenation in the ARS [Group B] than in the PEEP group [Group A]. As regards the Arterial Oxygen Tension, there was a continuous statistically significant rise in group B than in group A, 30 minutes after starting the ARS in the OR, before starting the ARS in the ICU, 30 minutes, 1 and 4 hours later [206.5 +/- 23.9,192.2 +/- 23.5, 250.7 +/- 31.9, 211.9 +/- 21.3 mmHg and 195.3 +/- 24.5 mm/Hg respectively in group B versus 126.9 +/- 10.1, 128.7111.6, 129.1 +/- 10.4, 129.8 +/- 9.4 mmHg and 130.1 +/- 9.7 mm/Hg respectively in group A] [P< 0.0001]. Additionally, there was a marked reduction in the postoperative hypoxemia, hypercarnia, atelectasis, prolonged intubation, infection and prolonged ICU stay in the ARS group. OPCAB patients in whom there is a reduction in lung compliance owing to the large volumes of intravenous fluids and compression of the right chest by the rotated heart during revascularization of the postero-lateral coronary vessels, applying an ARS in those patients greatly improves lung mechanics and arterial oxygen tension