Assessment of pain in sedated and mechanically ventilated patients: an observational study.

BACKGROUND: Critically ill patients often undergo unpleasant procedures. We quantified the effects of an unpleasant stimulus on physiological and behavioral parameters and evaluated how they are modified by sedation and analgesia. METHODS: A 6-month study in the 30-bed intensive care unit (ICU) of a university hospital examined 21 sedated patients from various diagnostic groups. Hemodynamic and respiratory parameters, pupil size, facial expression, muscle tone, body movement, and the Richmond Agitation-Sedation Scale (RASS) score were measured before and during intratracheal suctioning, first in sedated patients, after sedation was stopped, and after an opioid bolus. RESULTS: Before intratracheal suctioning, patients had RASS scores of -1.8 ± 1.2 (mean ± standard deviation; sedation), -0.6 ± 1.7 (sedation stop), and -0.9 ± 1.4 (analgesia) (P = 0.014). Intratracheal suctioning significantly increased RASS during both sedation (to -0.6 ± 1.7) and sedation stop (to 1.0 ± 1.5) (both P