Adherence to LPV in SICU and Associated Clinical Outcomes

Mechanical ventilation (MV) is one of the one organ support most frequently applied to patients admitted to intensive care units (ICUs). Despite considering as a life-saving intervention, MV may have detrimental effects, namely ventilator-induced lung injury (VILI). A mechanical breath with positive airway pressure may overstretch alveoli, especially in the non-dependent part of the lungs, and subsequently result in barotrauma and volutrauma. While cyclic opening and closing of alveoli during mechanical breath due to alveolar collapse at the end of expiration can cause atelec-trauma or cyclic atelectasis. All of these can lead to the activation of respiratory and systemic inflammatory response, so-called bio-trauma. To minimize the effects of MV on VILI, the lung protective mechanical ventilation (LPV) strategy have been proposed and now generally accepted as a standard practice in mechanically ventilated patients. The LPV strategy basically consists of ventilation with the low tidal volume of 6-8 mL/kg of predicted body weight (PBW) with limited plateau pressure of less than 30 cm H2O plus applying sufficient amount of positive end-expiratory pressure (PEEP) to prevent atelectasis. The LPV strategy has been clearly demonstrated benefits in not only patients with acute respiratory distress syndrome (ARDS) but also those with normal lungs including lessened respiratory and systemic inflammatory response and injured lungs, decreased duration of MV and length of stay (LOS), improved organ failure, and decreased pulmonary and other complications as well as mortality. Nevertheless, the adherence rate to the LPV strategy reported in the literatures is only approximately 40% in mechanically ventilated patients. For surgical patients, approximately 65% of those admitted to ICU require MV support either following operation or during their stay in ICU. To date, there is limited data regarding MV management in surgical patients who required MV support perioperatively. In addition, the difference in perioperative MV practices and their associated clinical outcomes has been not well determined in this setting. The aim of this study is to explore the current practice of MV according to the LPV strategy applied to surgical patients admitted to surgical ICU (SICU) and their associated clinical outcome. The primary outcome of this study is to determine the adherence rate to the LPV strategy at the initiation of MV support in mechanically ventilated patients in SICU. The LPV strategy in this study is defined as ventilation with the tidal volume of <8 mL/kg of PBW plus applying PEEP of at least 5 cm of water. The secondary outcomes are factors associated with the adherence to the LPV strategy, incidences of pulmonary and other complications, LOS in SICU and in hospital, SICU and hospital discharge status, and status at 28 and 90 days following the initiation of MV support. Patients are divided into two groups, LPV and Non-LPV, according to their MV setting and clinical outcomes are statistically compared between groups.