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Objective Nociceptive Assessment in Ventilated ICU Patients: A Feasibility Study Using Pupillometry and the Nociceptive Flexion Reflex
Published on: July 4, 2018
Applicability, Validity, and Reliability of the Japanese Version of the Behavioral Pain Scale for Critically Ill
Mitsuki Ikeda1,2, Haruhiko Hoshino3, Yujiro Matsuishi4
1Department of Emergency and Critical Care Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba 305-8575, Japan.
Insights
The Japanese Behavioral Pain Scale (BPS) shows acceptable validity and moderate reliability for assessing pain in critically ill pediatric patients. However, deep sedation can limit its effectiveness, requiring careful interpretation and specific training for accurate pain assessment.
Area of Science:
- Pediatric Critical Care Medicine
- Pain Management
- Clinical Assessment Tools
Background:
- Assessing pain in critically ill, mechanically ventilated children is challenging due to communication barriers and sedation.
- A standardized, objective tool like the Behavioral Pain Scale (BPS) is needed in Japanese pediatric intensive care units (PICUs).
- This study evaluated the Japanese BPS for clinical applicability, validity, and reliability in pediatric patients requiring mechanical ventilation.
Purpose of the Study:
- To validate the Japanese version of the Behavioral Pain Scale (BPS) for use in critically ill, mechanically ventilated pediatric patients.
- To assess the concurrent and convergent validity of the Japanese BPS against established pain scales.
- To determine the interrater reliability of the Japanese BPS among independent observers.
Main Methods:
- A single-center, prospective, cross-sectional observational study involving 37 pediatric patients (70 observations) requiring mechanical ventilation.
- Concurrent and convergent validity assessed using Spearman's rank correlation coefficients (ρ) between BPS, FLACC, and COMFORT-B scales.
- Interrater reliability evaluated using intraclass correlation coefficients (ICCs) and weighted kappa values; impact of sedation (RASS) and observer experience analyzed.
Main Results:
- High concurrent and convergent validity observed, with strong correlations between BPS, FLACC (ρ = 0.49-0.91), and COMFORT-B (ρ = 0.69-0.87).
- Moderate interrater reliability for the total BPS score (ICC = 0.66, weighted κ = 0.63-0.71).
- Deep sedation (RASS ≤ -4) in 68.6% of observations led to a floor effect, reducing reliability of subscales (e.g., upper limb movement κ = 0.08) and varying correlation strength with observer experience.
Conclusions:
- The Japanese BPS demonstrates acceptable validity and moderate reliability in mechanically ventilated pediatric patients.
- Clinical application requires careful interpretation due to a pronounced floor effect under deep sedation.
- Adequate training and familiarity with the scale are crucial for accurate assessment, especially in mixed adult-pediatric settings.
Abstract:
Background: Pain assessment in critically ill, mechanically ventilated pediatric patients is highly complex owing to communication barriers and the frequent use of sedation. A standardized, rapid, and objective tool such as the Behavioral Pain Scale (BPS) is urgently needed in Japanese pediatric intensive care units (PICUs), particularly in mixed adult-pediatric settings, to ensure consistent, multidisciplinary assessment. This study aimed to evaluate the clinical applicability, validity, and reliability of the Japanese version of the BPS in critically ill mechanically ventilated pediatric patients. Methods: This single-center, prospective cross-sectional observational study was conducted between October 2021 and March 2023. The final analysis included 70 observations from 37 pediatric patients who needed mechanical ventilation (MV). Concurrent and convergent validity were assessed using Spearman's rank correlation coefficients (ρ) between the BPS; the Face, Legs, Activity, Cry, Consolability (FLACC) scale; and the COMFORT-Behavior (COMFORT-B) scale. Interrater reliability was evaluated using intraclass correlation coefficients (ICCs) and weighted kappa values among the three independent observers. The sample size (52 observations) was calculated based on the kappa coefficient estimation. The impact of sedation depth (assessed using the Richmond Agitation-Sedation Scale [RASS]) and the observers' prior clinical experience with the evaluations were also analyzed. Results: Concurrent and convergent validity were high, showing strong correlations with the FLACC (ρ = 0.49-0.91) and COMFORT-B (ρ = 0.69-0.87) scales. The total BPS score showed moderate interrater reliability (ICC = 0.66, 95% CI = 0.55-0.76; weighted κ = 0.63-0.71). However, deep sedation (defined as a median RASS score ≤ -4 across observers), present in 68.6% of the observations, caused a pronounced floor effect that suppressed behavioral responses, even during painful procedures. Consequently, the reliability of fine motor subscales like "upper limb movement" (κ = 0.08) was slight and for "facial expression" (κ = 0.38), it was fair. Furthermore, the correlation strength with the FLACC scale varied significantly with observer experience, with the strongest correlation (ρ = 0.91) achieved by the observer with extensive adult ICU experience. Conclusions: As an initial validation, the Japanese version of the BPS has demonstrated acceptable validity and moderate reliability in mechanically ventilated pediatric patients. However, its clinical application requires careful interpretation because of the pronounced floor effect under deep sedation. Furthermore, accurate assessment depends heavily on specific training and familiarity with the adult-derived scale. With adequate training, the BPS has the potential to serve as an alternative tool and a valuable common multidisciplinary language in mixed intensive care settings. Future research should investigate whether implementing this tool improves multidisciplinary communication and clinical outcomes.