Preoperative lung function tests as a predictor for atelectasis in morbidly obese patients during anesthesia

摘要: Formation of atelectasis, defined as reversible collapse aerated lung, often occurs after induction anaesthesia with mechanical ventilation. As a consequence, there is risk for hypoxemia, altered hemodynamics and impaired respiratory system mechanics. In certain situations, the atelectasis formation increased its consequences may also be more difficult to manage. Anesthesia bariatric surgery in morbidly obese patients requiring one-lung ventilation (OLV) capnothorax are examples such situations.In Paper I (30 BMI > 40 kg/m2 scheduled surgery) recruit­ment maneuver followed by positive end-expiratory pressure (PEEP) re­duced amount improved oxygenation prolonged period time. PEEP or recruitment alone did not reduce atelectasis.In paper II we investigated whether it possible predict function impairment without pulmonary disease from preoperative lung test. Patients mild signs airway obstruction (reduced flow) spirometry developed less during anaesthesia.In III an experimental model sequential OLV using electrical impedance tomography (EIT) that real-time detected separation dynamic changes perfusion distributions. left side caused decrease cardiac output, arterial mixed venous saturation.In IV used our applied CO2-insufflation 16 cm H2O. We demonstrated level 12-16 H2O needed optimal lowest driving compromising hemodynamic variables. Thus, was closely related insufflation pressure. With insufficient PEEP, ventilation/perfusion mismatch ventilated redistribution blood flow non-ventilated occurred.