Effects of Noninvasive Versus Invasive Mechanical Ventilation on Sleep in the Intensive Care Unit – A Pilot Study

Rationale: Use of noninvasive ventilation (NIV) has increased in intensive care units, but sleep during NIV has received little attention. The authors surmised that due to frequent air leaks and mask discomfort, patients receiving NIV would manifest poorer sleep quality than those receiving invasive mechanical ventilation (INV). Methods: A prospective observational study on patients receiving NIV or INV for respiratory failure in a medical intensive care unit or coronary care unit. Patients were monitored by polysomnography for 24 hours with simultaneous collection of data on ventilator and environmental parameters. Results: Eight subjects in each group were studied. Mean total sleep time was 7.29 +1.78 hours (range: 0.57–13.82) in the NIV versus 11.74 +0.65 hours (8.95–15.19) in the INV group (p=0.034). Sleep efficiency was lower in NIV than INV group (30.4% versus 53.3%, respectively; p=0.013). The NIV group had lighter sleep than the INV group (mean % of Stage 1: 36.9% versus 17.2% of total sleep time, respectively; p=0.000), whereas no significant differences were found for other stages. Median total arousal and awakening indexes were higher in the NIV group (16.8/hour versus 4.4/hour and 5.3/hour versus 2.1/hour, respectively; p=0.005), as well as spontaneous arousals and awakenings (p=0.006 and p=0.005, respectively). Sedation was provided mostly by intermittent bolus in the NIV group whereas often by infusion in the INV group. Conclusion: Compared to INV, NIV in critically ill patients was associated with poorer quality and quantity of sleep. Future studies should determine whether adjustments in ventilator settings, mask type or fit, or use of sedation/analgaesia can improve sleep in patients receiving NIV.