Authors' objectives

To review instruments for measuring the effectiveness of sedation in adult and paediatric intensive care unit (ICU) patients.

Searching

MEDLINE and EMBASE were searched from 1966 to 1999 using the following text and keywords: 'sedation', 'stress', 'anxiety' or ' agitation'; 'ICU', 'intensive care unit', 'critically ill' or 'artificial ventilation'; 'score', 'scale' or 'assessment'. Other sources searched included the Cochrane Database of Systematic Reviews, the Cochrane Controlled Trials Register, the reference lists of all primary studies and review articles, and the authors' personal files. Studies published in full text or abstract form in any language were eligible.

Study selection

Assessment of study quality

The validity assessment was limited to a discussion of the methods used to assess measurement properties of the instrument examined.

Data extraction

Two reviewers extracted the following data: population details; study design; domains of sedation effectiveness and/or side-effects; and the internal consistency, reliability, validity and responsiveness of the instruments. Any disagreements were resolved by discussion and consensus.

Methods of synthesis

Results of the review

Twenty-five studies involving over 900 patients were included: 10 RCTs, 8 case series, and 7 studies that developed or assessed an instrument.

In addition to consciousness, most scales included items evaluating agitation, and/or ventilator synchrony. Pain, anxiety, reaction to endotracheal aspiration, and muscle tone were frequently measured. None of the studies evaluated the ability of the instrument to detect change in responsiveness over time, and there were several problems evident, such as the use of reference instruments that had not themselves been independently validated.

The Ramsay Scale: inter-rater reliability was high and scores were highly correlated with the GCS and the Sedation Agitation Scale. However, the instruments included items that were similar in content and structure.

The Comfort Scale was developed in a paediatric population and was comprised of 8 items. Good inter-rater reliability (0.84) and good correlation with a visual analogue score (0.75) was found. The validation of the instrument could have been strengthened by comparing a number of alternative measures of sedation.

The Sedation Agitation Scale was comprised of one item. There was very good inter-rater reliability (0.92) and high construct validity against the Ramsay Scale (0.91) and the Harris Scale (0.93). The Motor Activity Assessment Scale was comprised of one item. Good inter-rater reliability (0.83) and high correlation with a visual analogue scale was found.

Authors' conclusions

Many instruments have been used to measure sedation effectiveness in ICU patients. However, few of them exhibit satisfactory clinimetric properties. Additional information on the measuring properties of sedation effectiveness instruments is needed to help clinicians assess sedation at the bedside, to aid readers critically appraise the growing number of sedation studies in ICU literature, and to inform the design of future investigations.

CRD commentary

The aims were stated and the inclusion criteria were defined in terms of the participants, intervention and outcomes. Several relevant sources were searched, full details of the literature search were provided, no language restrictions were applied, and methods used to select studies were reported. Relevant information was presented in tabular format, and the methods used to extract data were described. Given the heterogeneity among studies, a narrative review was appropriate. Study characteristics were summarised, and the properties of the instruments were commented upon, although better quality sources of evidence were not highlighted. The authors drew attention to the use of inadequately validated instruments as the 'gold' standard. For ease of comparison, in reviewing the evidence it would have been simpler to group the studies by the instrument assessed.

The evidence presented supports the authors' conclusions.

Implications of the review for practice and research

Practice: The authors suggest that sedation at one point in time can be adequately measured in adults using the Ramsay Scale, the Sedation Agitation Scale and the Motor Activity Assessment Scale, and in children using the Comfort Scale.

Research: The authors state that additional information about the measuring properties of sedation effectiveness instruments is needed.

Bibliographic details

De Jonghe B, Cook D, Appere-De-Vecchi C, Guyatt G, Meade M, Outin H. Using and understanding sedation scoring systems: a systematic review. Intensive Care Medicine 2000; 26(3): 275-285. [PubMed: 10823383]

Other publications of related interest

1. Ramsay M, Savage T, Simpson B, Goodwin R. Controlled sedation with Alphaxalone-Alphadolone. BMJ 1974;2:656-9. 2. Amnuel B, Hamlett KW, Marx CM, Blumer JL. Assessing distress in paediatric intensive care environments: the Comfort Scale. J Paediatr Psychol 1992;17:95-109. 3. Riker RR, Picard JT, Fraser GL. Prospective evaluation of the Sedation-Agitation Scale for critically ill patients. Crit Care Med 1999;27:1325-9. 4. Devlin JW, Boleski G, Mlynarek M, Nerenz DR, Peterson E, Jankowski M, et al. Motor Activity Assessment Scale: a valid and reliable sedation scale for use with mechanically ventilated patients in an adult surgical intensive care unit. Crit Care Med 1999;27:1271-5.

Indexing Status

Subject indexing assigned by NLM

MeSH

Adult; Child; Conscious Sedation; Critical Illness; Humans; Neurologic Examination /standards; Reproducibility of Results

AccessionNumber

12000000837

Database entry date

28/02/2002

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.