Inhalational Sedation and Mechanical Power

In the intensive care unit (ICU), sedation is used to improve comfort and tolerance during mechanical ventilation, invasive diagnostic and therapeutic interventions or nursing care. The most commonly used sedatives are intravenous benzodiazepines and propofol. These agents are associated with over-sedation in 40 to 60% of patients, which can lead to prolonged intubation, delirium and drug-induced hypotension. Volatile anesthetics are increasingly used for sedation in European and Canadian intensive care units that offer advantages of rapid drug on and off effects and clearance via pulmonary exhalation with no active metabolites. Delivery of volatile agents in the ICU can be simply performed using a small lightweight and portable anesthetic reflector so-called anesthesia conserving device. Compared with intravenous sedatives, volatile anesthetics may allow shorter time to extubation and can facilitate mental recovery. In mechanically ventilated patients, a growing body of evidence suggests that the mechanical power (MP) plays an important role in the ventilator-induce lung injury (VILI) and prognosis in in both acute respiratory distress syndrome (ARDS) and non-ARDS patients. MP is the energy per unit time released to the respiratory system according to the tidal volume, PEEP, respiratory rate, and flow applied. In ARDS patients receiving invasive mechanical ventilation, high MP was associated an increased mortality. Moderate to deep sedation can inhibit the respiratory center and reduces the excessive respiratory drive, thereby reducing transpulmonary pressure and MP as well as probably reducing lung injury. The purpose of this study aims to investigate the effect of inhalation sedation on MP in mechanically ventilated patient admitted in the ICU. We hypothesize that MP in mechanically ventilated patients can be reduced by administering inhalational sedation.