Risk factors and prognosis of pain events during mechanical ventilation: a retrospective study

BACKGROUND Pain assessment is highly recommended in patients receiving mechanical ventilation. However, pain intensity and its impact on outcomes in these patients remain obscure. We collected the results of routine pain assessments, utilizing the behavioral pain scale (BPS), from 151 patients receiving mechanical ventilation. Risk factors associated with a pain event, defined as BPS of >5, and its impact on patient outcomes were investigated. METHODS A total of 151 consecutive adult patients receiving mechanical ventilation for more than 24 h in a single 10-bed ICU were enrolled in this study. The highest BPS within 48 h after the initiation of mechanical ventilation was collected, as well as information about the patients' characteristics and medication received. We also recorded patient outcomes, including time to successful weaning from mechanical ventilation, time to successful ICU discharge, and 30-day in-hospital mortality. Multivariate logistic regression analysis was used to determine factors independently associated with patients with a BPS of >5. Clinical outcomes were also assessed using multivariate logistic regression analysis, correcting for risk factors. RESULTS We analyzed 151 patients. The median highest BPS was 4. The percentage of patients who recorded a BPS of >5 was 19.9% (n = 30). Multivariate logistic regression analysis revealed that the disuse of fentanyl and inotropic support was an independent predictor of pain event. Multivariable Cox regression analysis suggested that the development of a BPS of >5 was associated with increased mortality and a not statistically significant trend towards prolonged mechanical ventilation. CONCLUSIONS A significant proportion of ventilated patients experienced a BPS of >5 soon after the initiation of mechanical ventilation. Disuse of fentanyl and use of inotropic agents increased the risk of developing a BPS of >5 during mechanical ventilation. An association between adequate analgesia and improved patient outcomes provides a rationale for the assessment of pain during mechanical ventilation, with subsequent intervention if necessary. Pain events were common among ventilated patients. In critical care settings, appropriate and adequate pain management is warranted, given the association with improved patient outcomes.