Comparsion of Selected Sedation Scales for Reporting Opioid–Induced Sedation Assessment

Allison Theresa Nisbet, MSN, CPN, AOCNS, RN-BC; Florence Mooney-Cotter, MSN, CNS-BC, RN-BC


Pain Manag Nurs. 2009;10(3):154-164. 

In This Article

Abstract and Introduction


A descriptive survey-based study was undertaken to test the validity and reliability of three scales that are used to assess sedation during opioid administration for pain management: the Inova Health System Sedation Scale (ISS), the Richmond Agitation and Sedation Scale (RASS), and the Pasero Opioid-Induced Sedation Scale (POSS). The study was conducted in a large (830 beds) suburban level I trauma hospital with a random convenience sample of 96 medical-surgical nurses. The study reports: measures of reliability and validity of each scale and significant findings related to correct nursing score and selected actions; nurses' ratings of each scale in terms of combined ease of use; information provided by the scale to inform clinical decisions; and nursing confidence measures. Both the RASS and the POSS demonstrated adequate measures of reliability and validity for measurement of sedation during opioid administration for pain management. However, the POSS scored higher in combined measures of ease of use, nursing confidence, and usefulness of information provided to make clinical decisions. The POSS also yielded the highest percentage agreement with the correct score and correct nursing actions chosen by the nurse among the three scales tested. Study results have clinical significance for accuracy of clinical assessments and subsequent actions on behalf of patients experiencing advancing sedation during opioid analgesia. The POSS can be recommended as a superior sedation scale for the measurement of sedation during opioid administration for pain management. 2009 by the American Society for Pain Management Nursing


Opioid-induced sedation represents a continuum of levels of consciousness and arousability ideally measured by reliable and valid criteria that are applied in clinical practice for safe and effective administration of opioid analgesics (American Society for Pain Management Nursing [ASPMN], 2009).

Opioid-induced respiratory depression is a concerning decrease in the effectiveness of an individual's ventilatory function after opioid administration (ASPMN, 2009).

For the purposes of this study, sedation is recognized as a relatively common side effect of opioid analgesia (Pasero & McCaffery, 2002; Szalados & Boysen, 1998), and advancing sedation has been identified as a precedent to clinically significant respiratory depression (Pasero & McCaffery, 2002). As such, nurses should systematically assess and document in the medical record the incidence and severity of sedation during opioid administration for pain management. Furthermore, the assessment should lead the nurse to make appropriate decisions about how to proceed with opioid administration.

Although sedation occurs on a continuum, it does not correlate directly with laboratory values of opioid drug levels (Szalados & Boysen, 1998). As a result, sedation, much like pain, must be serially assessed to identify discrete levels at any given moment in time and to identify incremental changes in direction of sedation level (increasing or decreasing). The incidence and severity of opioid-induced sedation is influenced by many factors, including whether the patient is opioid tolerant (taking regular daily doses of opioids for several days) or opioid naive (Pasero & McCaffery, 2002), concurrent administration of other sedating medications (such as benzodiazepines) (Szalados & Boysen, 1998), and the patient's general health and clinical condition (Smith, 2007). Patients at extremes of age (the very young and the very old), with end-organ damage affecting opioid metabolism and elimination, with obstructive sleep apnea (diagnosed or not), and with baseline alterations in respiratory or neurological function are at a higher risk for increased sedation and subsequent respiratory depression as a complication of opioid therapy (Pasero & McCaffery, 2002; Smith, 2007). In addition, some pain management therapies, including intermittent intramuscular, intravenous, or subcutaneous opioid injections, intravenous patient-controlled analgesia (IV PCA), and intraspinal pain management, may increase the risk of sedation.

The literature has addressed the monitoring of purposeful goal-directed sedation in select settings. There is an abundance of research on this aspect of care in the critical care setting (Binnekade, Vroom, & DeVos, 2006; Ely, 2003; Fraser & Riker, 2007; Payen, Chanques, & Mantz, 2007; Pun, 2007; Ramsay, 2000; Sessler, Gosnell, Grap, Brophy, O'Neal, Keane et al., 2002; Szalados & Boysen, 1998). Guidelines for the administration and monitoring of sedation, analgesia, and neuromuscular blockade in critically ill patients were released in 2002 (Nasraway, Jacobi, Murray, & Lumb et al., 2002). The American Society of Anesthesiologists (ASA) released guidelines and standards clarifying the varying states along the continuum of sedation (2004a), differentiated monitored analgesic care (MAC), and moderate/conscious sedation (2004b) and detailed standards for basic anesthetic monitoring (2005). The administration and monitoring of sedation in ambulatory care settings, such as during endoscopic procedures, has also been discussed (Moos, 2006). More recently, the literature has addressed palliative sedation at the end of life (Bruce, Hendrix, & Gentry, 2006).

There is a lack of research on assessment of opioid-induced sedation in the medical-surgical environment. The importance of accurate sedation assessment and communication of patient clinical status for appropriate decision making to prevent respiratory depression in this area has been discussed in the literature for several years (Pasero, 2009; Pasero, Manworren, & McCaffery, 2007; Pasero & McCaffery, 1994; 2002; Pasero, Portenoy, & McCaffery, 1999; Smith, 2007). Interestingly, there is a lack of research identifying the most valid and reliable means for assessment of sedation during opioid administration for pain management in the medical-surgical environment.


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