Efficacy and Safety of Three Alveolar Recruitment Manoeuvres after Off-Pump Coronary Artery Bypass Grafting
*Mikhail Y. Kirov Department Of Anesthesiology And Intensive Care Medicine, Northern State Medical University, Russian Federation, Russian Federation
*Corresponding Author: Mikhail Y. Kirov
Department Of Anesthesiology And Intensive Care Medicine, Northern State Medical University, Russian Federation, Russian Federation Email:email@example.com
Published on: 2016-02-22
The aim of study was to assess the efficacy and safety of three different modes of alveolar recruitment manoeuvre (RM) and to evaluate their influence on early postoperative period after off-pump coronary artery bypass grafting (OPCAB). We randomized 80 adult patients after OPCAB to four groups: ?PAP-40 group was exposed to RM by changing the ventilator mode to continuous positive airway pressure of 40 cm H2O for 40 seconds; in a Peak-40 group, RM was achieved by inflating the lungs at constant flow until a peak inspiratory pressure of 40 cm H2O was reached and held for 40 seconds; the PEEP-15 group received RM by raising the positive end-expiratory pressure to 15 cm H2O for five minutes; the control group received no RM. Arterial oxygenation and dynamic compliance increased in all groups receiving RM (P < 0.017). In the CPAP-40 group, mean arterial pressure decreased significantly during RM (P = 0.01). In the PEEP-15 group, the duration of respiratory support was shortened by 1 hr compared with the control group (P = 0.012). Alveolar RM using Peak-40 and PEEP-15 improved oxygenation after OPCAB without negative influence on haemodynamics. Application of a PEEP of 15 cm H2O for five minutes reduced the time to tracheal extubation.
The formation of atelectases is a common complication of mechanical ventilation during general anaesthesia. Chest radiograms display crest-shaped changes of increased density in dependent lung regions within minutes after induction of anaesthesia and neuromuscular blockade. These changes are concerted by a fall in functional residual capacity and a cranial displacement of the diaphragm. Following cardiac surgery, collapse of pulmonary parenchyma can persist postoperatively and contribute to increased morbidity and additional health care costs. Notably, the incidence of atelectases is particularly high after cardiosurgical interventions because the patients are exposed to multiple promoting factors. Attention also has been paid to the sternotomy per se and to lung compression by mediastinal structures. Moreover, the use of retractors during the surgery, manipulations in the pleural cavities and mechanical ventilation with high inspiratory oxygen fractions might all add to the de-aeration of lung tissue. Over the last years, different strategies have been used to re-expand collapsed lung areas, both intra- and postoperatively. Several studies have shown that the application of an alveolar recruitment manoeuvre (RM) can improve respiratory function by re-opening atelectatic regions after cardiac surgery. It is widely accepted that RM reduces intrapulmonary shunt and ventilation-perfusion mismatch and subsequently improves arterial oxygenation. However, some effects of the RM might be deleterious since it might affect the cardiovascular system adversely; besides this it might induce barotrauma, volumotrauma and biotraum.