Mechanical Ventilation Strategies in Patients with Intra-Abdominal Hypertension and Open Abdomen

Abstract

Intraabdominal hypertension (IAH) is an important cause of intraabdominal organ dysfunction and has adverse effects on chest mechanics including an increase in intrathoracic pressure, a decrease in lung volumes, and chest wall compliance due to cephalic shift of diaphragm, and collapse in alveoli leading to hypoxemia. Management with mechanical ventilation (MV) strategies has a pivotal role to reduce these adverse effects and worsening lung injury. There is a lack of studies and evidence on MV strategies in patients with IAH. This study analyzes the recent literature. The definition of IAH in critically ill patients, risk factors, intra-abdominal pressure (IAP) measurement, IAH treatment, MV management in patients with respiratory failure, modes of MV, the role of assisted breathing, the management of airway pressures, optimal driving pressure, targeted plateau pressure, positive end-expiratory pressure (PEEP) and usage of the prone position are discussed. Elevated IAP decreases lung compliance. Therefore, MV management should be performed with the guidance of transpulmonary pressure (Ptp) and IAP measurements in patients with IAH. Tidal volüme (TV) should be kept equal to or lower than 6-8 ml/kg and lung-protective MV strategies should be applied. The patient's need for PEEP over 10 cm H2 0 during MV is a predictor of increased IAP. Since a PEEP requirement higher than 10 cm H2 O may be a predictor of increased IAP, the lowest PEEP level suitable to patients’ condition should be set.