Perioperative management of obese patients

Obesity is a metabolic disease that is on the increase all over the world. Up to 35% of the population in North America and 15-20% in Europe can be considered obese. Since these patients are characterised by several systemic physiopathological alterations, the perioperative management may present some problems, mainly related to their respiratory system. Body mass is an important determinant of respiratory function before and during anaesthesia not only in morbidly but also in moderately obese patients. These can manifest as (a) reduced lung volume with increased atelectasis; (b)derangements in respiratory system, lung and chest wall compliance and increased resistance; and (c) moderate to severe hypoxaemia. These physiological alterations are more marked in obese patients with hypercapnic syndrome or obstructive sleep apnoea syndrome. The suggested perioperative ventilation management includes (a) awake and/or facilitated endotracheal intubation by using a video-laryngoscope; (b) tidal volume of 6-10 ml kg(-1) ideal body weight, increasing respiratory rate to maintain physiological PaCO2, while avoiding intrinsic positive end-expiratory pressure (PEEPi); and (c) a recruitment manoeuvre (35-55 cmH2O for 6 s) followed by the application of an end-expiratory pressure (PEEP) of 10 cmH2O. The recruitment manoeuvre should always be performed only when a volemic and haemodynamic stabilisation is reached after induction of anaesthesia. In the postoperative period, beach chair position, aggressive physiotherapy, noninvasive respiratory support and short-term recovery in intermediate critical care units with care of fluid management and pain may be useful to reduce pulmonary complications.