Maintaining spontaneous ventilation during surgery—a review article
Mechanical ventilation is necessary during many surgical procedures, however a paradigm shift in ventilation has taken place in the past decades. There is convincing evidence that neuromuscular blockade and subsequent controlled mechanical ventilation applying intermittent positive pressure, also in patients with non-injured, healthy lungs, may impair the respiratory system, leading to postoperative pulmonary complications (PPCs), resulting in worse clinical outcome, prolonged hospitalization time and increased cost of hospital care. Multifactorial pathophysiology of ventilator induced lung injury (VILI) has been evaluated and a pulmonary protective ventilatory strategy [lung protective ventilation (LPV)], including the use of low tidal volumes [6 mL/kg, ideal body weight (IBW)], moderate or optimal levels of positive end-expiratory pressure (PEEP) and applying regular or targeted alveolar recruitment maneuvers (ARMs), has been developed. Recognizing the role of neuromuscular blockade during general anesthesia and even the importance of avoiding residual neuromuscular blockade in the early postoperative period regarding to postoperative respiratory impairment have become another, newer direction of research. Despite promising and convincing results of recent clinical trials, incidence of PPCs could not be reduced significantly and lung protective ventilation has remained to be a “hot topic” among researchers in the field of anesthesia and critical care. Maintaining spontaneous breathing during general anesthesia has some pathophysiological rationale worth to be dealt with, because it may be one of the options for further improvement. Physiology, advantages, disadvantages and potential role of spontaneous breathing during surgery as compared to intermittent positive pressure ventilation will be described in this article.