Effects of sedation on clinical, gasometric, and respiratory muscle parameters in critically ill chronic obstructive pulmonary disease patients

Abstract

BackgroundSevere chronic obstructive pulmonary disease (COPD) exacerbation requiring mechanical ventilation is commonly encountered in the ICU. Sedation is necessary to facilitate mechanical ventilation. The effect of no-sedation strategy on different patient parameters on the ventilator has not yet been well studied. The aim of this study was to test the efficacy of no-sedation protocol in controlling COPD patient’s gasometric and clinical parameters during mechanical ventilation.Patients and methodsPatients with COPD who required mechanical ventilation were randomized to either: sedated with daily interruption (control group) (n=50) or nonsedated group (n=47). The change in the partial pressure of arterial CO2 (PaCO2) was the primary outcome measure. Secondary outcome measures included: changes in pH, heart rate (HR), mean arterial blood pressure (MAP), respiratory rate, airway occlusion pressure (P0.1), and negative inspiratory force (NIF). Recordings for arterial blood gases, HR, MAP, and respiratory rate were performed as baseline at intubation, 1, 2, 12, 24, and 48h after intubation. NIF and P0.1 were recorded 48 h after intubation.ResultsNo significant difference was found in baseline recordings of PaCO2, pH, HR, MAP, and respiratory rate between the sedated and nonsedated groups. Further recordings of PaCO2 (P_1, P_2, P_3, and P_4<0.001, P_5=0.005), HR (P<0.001), and respiratory rate (P<0.001) were significantly higher in the nonsedated group. The rate of correction of pH from acidosis was faster among the sedated patients. MAP was significantly higher in nonsedated patients in recordings 2, 12, and 48 h after intubation (P_1=0.9, P_2<0.001, P_3<0.001, P_4=0.87, P_5<0.001). No significant difference was found in NIF or P0.1 between the two groups (P=0.8 and 0.1, respectively).ConclusionCOPD patients managed by no-sedation strategy had higher PaCO2, HR, MAP, and respiratory rate. No-sedation had no significant effect on respiratory muscle function when compared with daily interruption of sedation.