Responses to noxious stimuli in sedated mechanically ventilatedadults

Objective: To determine the effect of sedation on physiologic responses and comfort before, during and after a noxious stimulus (endotracheal tube suctioning). Methods: The sample was a subset of a larger, longitudinal descriptive study, blood for endorphins and saliva for alpha-amylase were obtained before and after suctioning. Heart rate (HR), respiration rate (RR), oxygen saturation (SPO₂), and arm and leg actigraphy were continuously recorded. Results: 67 subjects from medical and surgical ICUs were primarily deeply (37%) or mildly sedated (54%) prior to suctioning. Alpha-amylase increased post suctioning (p=0.04); endorphins did not change (p=0.58). Neither were modified by sedation. There were no changes in HR, RR or SPO2 post suctioning. Arm (p=0.007) and leg actigraphy (p=0.057) changed from baseline and depended on sedation level (p=0.0005). Conclusions: While a stress marker did increase during suctioning, only the measure of patient arm movement was significantly affected by sedation level.