One lung anesthesia

ABSTRACT

Thoracic anesthesia with one lung ventilation is challenging. The anesthetist is faced with demands of establishing proper isolation of one lung from the other in order to facilitate good surgical exposure and prevent intraoperative complications. Due to advances in one lung ventilation [OLV] strategies and equipment, complex intrathoracic procedures are being performed with success. During onelung ventilation, mismatch of perfusion leads to an increase in shunt and dead space. Hypoxemia is an inevitable adverse consequence of OLV. Prompt management is required. This may particularly occur with high airway pressure caused by malpositioned double lumen tube or endobronchial blocker causing incomplete lung ventilation and/or airway obstruction. Other causes may be bronchospasm, air trapping with dynamic hyperinflation pneumothorax of the ventilated lung and coughing due to inadequate muscle relaxation. One lung induced acute lung injury [ALI] must be recognized. Acute lung injury [ALI] is a major cause of overall mortality after thoracic surgery. Protective ventilation strategies have been identified and recommended by researchers for implementation during OLV. This includes small tidal volumes based on ideal body weight, reducing the fraction of inspired oxygen [FiO2], use of positive end-expiratory pressure [PEEP] to the ventilated lung, and low peak and plateau airway pressures. One-lung ventilation has to be managed from the start before beginning OLV till the end of OLV [in order to prevent complications like ALI]. Extreme care is required during re-expansion of the lung towards the end of OLV. Noninvasive ventilation may be used during this period to improve oxygenation