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Updated: Oct 24, 2025

Objective Nociceptive Assessment in Ventilated ICU Patients: A Feasibility Study Using Pupillometry and the Nociceptive Flexion Reflex
Published on: July 4, 2018
Evaluation of pain severity in critically ill patients on mechanical ventilation
Yumi Ito1, Koji Teruya2, Emiko Nakajima1
1Department of Nursing, Faculty of Health Sciences, Kyorin University, Tokyo, Japan.
Objectives:
To elucidate how patients' illness severity, respiratory status, or haemodynamics are associated with the pain score of critically ill patients.
Methods:
This was an observational study of patients on mechanical ventilation after surgeries. At rest and on turning, patient pain was evaluated using the Behavioural Pain Scale (BPS) and the Critical-Care Pain Observation Tool (CPOT). Related factors were collected from medical records and analysed.
Findings:
Multiple logistic regression analysis was performed using data on 127 scenarios. An increase of >2 in BPS score on turning was affected by the Acute Physiology and Chronic Health Evaluation (APACHE) II score (odds ratio [OR] = 0.864), systolic blood pressure at rest (OR = 1.032), BPS at rest (OR = 0.638), heart rate difference (OR = 1.124), and tidal volume difference (OR = 0.548). An increase of >2 in CPOT on turning score was associated with the APACHE II score (OR = 0.894), Sequential Organ Failure Assessment score (OR = 1.248), systolic blood pressure at rest (OR = 1.025), heart rate difference (OR = 1.096), and tidal volume difference (OR = 0.578).
Conclusion:
The Behavioural Pain Scale and the Critical-Care Pain Observation Tools were associated with illness severity and haemodynamics. A reduction in tidal volume may be useful in assessing pain.
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