An evaluation of instruments for scoring physiological and behavioral cues of pain, non-pain related distress, and adequacy of analgesia and sedation in pediatric mechanically ventilated patients: A systematic review

Abstract

Objectives

Advancing technology allows for successful treatment of children with life-threatening illnesses. Effectively assessing and optimally treating a child's distress during their stay in the Pediatric Intensive Care Unit (PICU) is paramount. Objective measures of distress in mechanically ventilated pediatric patients are increasingly available but few have been evaluated. The objectives of this systematic review were to identify available instruments appropriate for measuring physiological and behavioral cues of pain, non-pain related distress, and adequacy of analgesia and sedation in mechanically ventilated pediatric patients, and evaluate these instruments in terms of their psychometric properties.

Design

A systematic review of original and validation reports of objective instruments to measure pain and non-pain related distress, and adequacy of analgesia and sedation in mechanically ventilated PICU patients was undertaken.

Data sources

A comprehensive search was conducted in 10 databases from January 1970 to June 2011. Reference lists of relevant articles were reviewed to identify additional articles.

Review methods

Studies were included in the review if they met pre-established eligibility criteria. Two independent reviewers reviewed studies for inclusion, assessed quality, and extracted data.

Results

Twenty-five articles were included, identifying 15 instruments. The instruments had different foci including: assessing pain, non-pain related distress, and sedation (n = 2); assessing pain exclusively (n = 4); assessing sedation exclusively (n = 7), assessing sedation in mechanically ventilated muscle relaxed PICU patients (n = 1); and assessing delirium in mechanically ventilated PICU patients (n = 1). The Comfort Scale demonstrated the greatest clinical utility in the assessment of pain, non-pain related distress, and sedation in mechanically ventilated pediatric patients. Modified FLACC and the MAPS are more appropriate, however, for the assessment of procedural pain and other brief painful events. More work is required on instruments for the assessment of distress in mechanically ventilated muscle relaxed PICU patients, and the assessment of delirium in PICU patients.

Conclusions

This review provides essential information to guide PICU clinicians in choosing instruments to assess pain, non-pain related distress, and adequacy of analgesia and sedation in mechanically ventilated pediatric patients. Effective knowledge translation is essential in the implementation, adoption, and successful use of these instruments.

Introduction

Mechanical ventilation is a central and increasingly used treatment modality in Pediatric Intensive Care Units (PICUs). PICUs worldwide have reported that 20–64% of the children admitted require ventilation (Farias et al., 2004, Khemani et al., 2009). Mechanical ventilation complicates the management of pain and non-pain related distress, that is, responses that occur when the child is exposed to non-pain related external stimuli that elicit fear, anxiety, anger, frustration, depression, distress, dysphoria, or unhappiness (von Baeyer and Spagrud, 2007). Ventilated patients are sedated and often unable to speak, which makes self-report of pain and non-pain related distress difficult (von Baeyer and Spagrud, 2007, Ambuel et al., 1992, Marx et al., 1994, Van Dijk et al., 2000). Young children lack the verbal and cognitive ability to effectively express their emotions related to pain and other negative non-pain related emotions. Additionally, infants who undergo surgery for congenital heart disease demonstrate conduction abnormalities, require cardiac pacing and cardiovascular medications, and experience catecholamine abnormalities that alter the physiologic responses that caregivers commonly look for as cues to intervene (Connolly et al., 2004). Therefore, the assessment of pain and non-pain related distress is difficult in mechanically ventilated children due to age, intubation, sedation, and the potential inability to manifest the predetermined non-verbal signs that caregivers may recognize in completion of their assessment.

When self-report, the “reference standard” for the assessment of pain and non-pain distress, is not available, the clinical judgment of the attending nurse or physician is the next logical choice. This measure is subject to many interpretations and may lead to disagreements within the clinical team. Disagreements can result in significant fluctuations in the administration and discontinuation of analgesia and sedation and predispose the patient to adverse reactions and over- or under-sedation. Length of ventilation and PICU stay, and long-term psychological and neurodevelopmental factors may also be affected by fluctuations in analgesia and sedation (Carnevale and Ducharme, 1997).

To address these problems, systematic assessment instruments have been developed to objectively measure the effectiveness of analgesia and sedation in treating pain and non-pain related distress in mechanically ventilated and non-verbal patients (Marx et al., 1994). Theoretically, these scales provide a more consistent measure of the adequacy of analgesia and sedation in controlling patient's pain and non-pain related distress than do a nurse or physician descriptive analog or visual analog scale (Marx et al., 1994). These scales allow for fewer discrepancies between individual assessments of pain and non-pain related distress and the patient's response to the analgesia and sedation. These scales are increasingly available but few have been evaluated for efficacy and/or effectiveness in PICU mechanically ventilated patients.

Two previous systematic reviews examined instruments for assessing either pain or sedation in critically ill patients. De Jonghe et al. (2000) summarized available systematic assessment instruments for the evaluation of sedation in both adult and pediatric ICU patients. The authors identified 25 scales for assessing sedation in critically ill patients of which five had been evaluated in a PICU setting. They concluded that the Comfort Scale was the most appropriate measure of sedation in PICU patients, but there was insufficient knowledge about the instrument's ability to detect change in a patient's condition over time (De Jonghe et al., 2000). The authors limited their assessment of the Comfort Scale's psychometric properties to the evaluation completed in the original report of this study and did not comment on the psychometric properties of the other four scales identified. Since the time of this review additional sedation scales have been developed and published.

A more recent systematic review identifed all published observational measures for pain in children age 3–18 regardless of patient setting. The authors did not limit the measures they reviewed to systematic assessment scales. They included global rating scales such as visual analog scales and numerical rating scales, and recommended that the Comfort Scale be used to assess pain in PICU patients based on their level of evidence assessment (von Baeyer and Spagrud, 2007). The authors did not identify any other instruments suitable in this population and did not comment on the modified form of the Comfort Scale, the Comfort-Behavioral Scale. Information on the psychometric properties of the measures beyond validity and reliability was not provided.

Neither of these two reviews considered mechanically ventilated pediatric patients as a subgroup within the critical care setting, and the concept of delirium as a component of non-pain related distress was not considered. No instruments for the assessment of pain or sedation in mechanically ventilated patients who were muscle relaxed were identified.

The objectives of this systematic review were to: (1) identify available instruments appropriate for measuring physiological and behavioral cues of pain, non-pain related distress, and adequacy of analgesia and sedation in mechanically ventilated PICU patients; (2) describe each instrument's development; (3) describe the physiological and behavioral variables they assess; and (4) evaluate the instruments’ psychometric properties.