Special Feature
Assessment of Pain in Non-vocal or Unresponsive ICU Patients
By Linda L. Chlan, PhD, RN, FAAN
Dean’s Distinguished Professor of Symptom Management Research, The Ohio State University, College of Nursing
Dr. Chlan reports that she receives grant/research support from Hospira.
Pain — defined as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage"1 is a common symptom experienced by critically ill patients. Pain arises from many sources for intensive care unit (ICU) patients — from treatments or procedures, such as endotracheal tube suctioning or chest tube insertion, to incisional pain from surgical wounds. Patients with pre-existing chronic conditions, such as back pain or rheumatoid arthritis, can have their pain exacerbated by bed rest or from inadvertent suspension of home medication therapy. While self reporting using a valid and reliable pain assessment instrument is the most accurate method to assess pain, this is not always possible with ICU patients, particularly those patients who are unresponsive or non-vocal due to intubation and mechanical ventilation.
ICU clinicians may assume that because patients are non-vocal or are unresponsive, they do not experience pain. However, this is an erroneous assumption. Of the millions of patients admitted to the ICU each year, approximately 71% recall experiencing pain during their stay.2 Thus, regular pain assessment and appropriate intervention strategies are needed to effectively manage pain for all ICU patients, regardless of whether they are vocal and alert. However, pain assessment in non-vocal patients presents an immense challenge for ICU clinicians, which is further compounded in those patients who are unresponsive due to their current medical condition. Appropriate assessment and management of pain among ICU patients is of utmost importance to promote positive outcomes for these patients.
This special feature will review the most commonly used instruments for pain assessment with non-vocal or unresponsive ICU patients, and will provide recommendations for assessment. The reader is advised to consult the recently published Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the Intensive Care Unit (ICU-PAD) for suggestions on specific medications for the treatment of pain, as well as the appropriate implementation of non-pharmacological interventions to promote effective pain management for all ICU patients.3
BRIEF REVIEW OF RELIABILITY AND VALIDITY OF INSTRUMENTS
A brief review of reliability and validity concepts is warranted to guide the clinician in the selection of a psychometrically sound pain measurement instrument. Any instrument needs to be reliable and valid to effectively manage symptoms such as pain. Generally speaking, reliability is the degree of consistency and repeatability of the scores on an instrument.4 Validity refers to the ability of an instrument to measure exactly what it is supposed to measure and nothing else.4 For example with any pain assessment instrument, a valid instrument would measure pain and only pain, not any other symptoms such as anxiety or depression. While there are many different types of reliability and validity, an in-depth discussion of this topic is beyond the scope of this article.
BEHAVIORAL PAIN ASSESSMENT INSTRUMENTS
To determine the presence of pain accurately in non-vocal or unresponsive critically ill patients, a number of instruments that measure pain-related behaviors can be used in practice. The clinician is advised to keep in mind that the most frequently used pain assessment instruments for non-vocal patients only indicate the presence of pain, not the intensity or severity of pain. At the present time, there are no instruments that specifically measure the intensity and severity of pain in non-vocal or unresponsive critically ill patients.
There are a number of instruments that can be used to measure pain in critically ill adults. These instruments include the Pain Assessment and Intervention Notation Algorithm, the Nonverbal Pain Assessment Tool, the Adult Nonverbal Pain Scale, the Behavioral Pain Scale (BPS), and the Critical-Care Pain Observation Tool (CPOT). Another population for which pain assessment is a challenge is in persons with dementia. Two instruments that are frequently used for pain assessment with this population are the Checklist of Nonverbal Pain Indicators and the Pain Assessment in Advanced Dementia. Neither of these instruments has been tested extensively or validated in the ICU setting, and they should not be used for pain assessment in the critically ill. This article will focus on two instruments — BPS and CPOT — that are used most frequently and have good reported reliability and validity (psychometric properties) across a number of studies.
THE BEHAVIORAL PAIN SCALE
The BPS consists of three items identifying unique behaviors in patients undergoing noxious stimuli. Each of the three pain-related behaviors has corresponding descriptors that are scored from 1 to 4, depending on the description judged by the clinician to be present that coincides with each pain-related behavior. A total score on the BPS ranges from 3 (no pain) to 12 (most pain).5 The individual items on the BPS describe pain-related behaviors associated with facial expression (relaxed = 1, to grimacing = 4), upper limb movements (no movements = 1, to permanently retracted = 4), and compliance with mechanical ventilation (tolerating movement = 1, to unable to control ventilation = 4). Although the BPS yields a "score," any individual score does not correspond with pain intensity, only the presence of behaviors associated with painful or noxious stimuli. In fact, a BPS score of 3 does not necessarily indicate a patient does not have pain; the score reflects an absence of the defined pain-related behaviors corresponding to each item. This is a major limitation of the BPS.
THE CRITICAL-CARE PAIN OBSERVATION TOOL
The CPOT contains four domains and is scored on each domain as 0, 1, or 2 depending on the judgment of the clinician.7 The four domains of pain-related behaviors include: facial expression (relaxed/neutral observed = 0, to grimacing = 2), body movements (no movement = 0, to restlessness = 2), muscle tension (relaxed = 0, to very tense/rigid = 2), compliance with ventilator (tolerating ventilator = 0, to fighting the ventilator = 2), or vocalization. The vocalization domain for non-intubated patients is scored from talking in normal voice (0) to crying out, sobbing (2). The CPOT can be used in both intubated and non-intubated ICU patients with the addition of the vocalization domain.
The CPOT was developed and tested extensively by nurse-researcher Dr. Celine Gélinas. Interestingly, Dr. Gélinas has conducted studies with nurses themselves evaluating the feasibility of using the CPOT in ICU nursing practice. The findings from this research demonstrate that the ICU nurses appraise the CPOT as clear and simple to use, find it helpful in their practice, and would recommend its use routinely.7 Further, a replication study of the reliability and validity of the CPOT has been reported by Keane,8 who found the instrument to be psychometrically sound for pain assessment in the ICU clinical setting. The CPOT is widely used in the United States and Canada. It is available in English and French, and work is underway to translate it into Finnish, Portuguese, Italian, and Swedish.7
PAIN ASSESSMENT TIPS AND RECOMMENDATIONS
To reiterate, it is vitally important that ICU clinicians not assume that patients who are unresponsive or non-vocal are not experiencing pain. Many ICU patients recall distressing pain after their ICU stays.2 To manage pain effectively among ICU patients, consistent and systematic assessment of pain presence is needed, using reliable and valid instruments. Any pain assessment instrument needs to be non-burdensome for alert, interactive patients. Further, pain assessment instruments should be easy to use for ICU clinicians, particularly for the ICU nursing staff who have the primary responsibility for pain management. If any instrument is not routinely used to assess pain presence or is not consistently and correctly used in practice to assess pain, infective symptom management will arise that can lead to less than ideal patient outcomes and experiences.
For many years, ICU clinicians used elevations in vital signs, particularly increases in heart rate and blood pressure, as indicators of pain. Research over the past several years has documented that vital signs are extremely inaccurate indicators of pain and should not be used in isolation to guide pain assessment and intervention.9 Vital signs may be used as a trigger to conduct a pain assessment with a reliable and valid instrument such as the CPOT.
The ICU-PAD clinical practice guidelines3 highlight the importance of pain as the first symptom that requires regular assessment and reassessment to guide appropriate pharmacological and non-pharmacological treatments to manage pain among ICU patients. The guidelines suggest clinicians employ either the BPS or the CPOT for pain assessment.3 Since the publication of the ICU-PAD guidelines, additional research has been published to further guide the clinician in selection of the best pain assessment instruments for non-vocal or unresponsive ICU patients. The current best available evidence recommends the CPOT over the BPS.9 The CPOT has been tested in both verbal and non-verbal ICU patients, which may make the CPOT much more applicable to ICU clinical practice settings.9 Further, the CPOT has superior reliability and validity, and is thus recommended over the BPS for pain assessment in critically ill patients.9
SUMMARY
While pain remains a significant symptom requiring appropriate assessment and management for all ICU patients, non-vocal and unresponsive patients present a unique challenge for ICU clinicians. Self-report should be attempted in any alert patient regardless of whether the patient is receiving mechanical ventilatory support. A set of simple questions can elicit pain presence and intensity. Simply ask the patient, "Are you having pain?" (yes/no). Then ask a patient to rate on a scale of zero (no pain) to 10 (worst pain ever) to get an idea of intensity. If able, have any alert patient point to where the pain is located. Patients can and will engage in symptom assessment if given the opportunity to participate. For those patients who are not alert or are unresponsive, the CPOT is recommended for assessment of pain presence.
A limitation of any of the commonly used behavioral pain scales with ICU patients is that none of the scales truly quantify or describe pain. Alert, verbal patients will frequently use words such as "stabbing" or "burning" when describing their pain. Further, none of the behavioral pain scales used in the ICU do not take into consideration any chronic pain conditions patients may have while receiving care in the critical care setting. However, behavioral pain scales can reliably assess for the presence of pain and should be consistently used to guide pain management in non-vocal or unresponsive ICU patients.
REFERENCES
- International Association for the Study of Pain (IASP) Taxonomy. http://www.iasp-pain.org/Education/Content.aspx?ItemNumber=1698&&navItemNumber=576. Accessed Nov. 19, 2014.
- Klein D, et al. Pain assessment in the intensive care unit: Development and psychometric testing of the Nonverbal Pain Assessment Tool. Heart Lung 2010;39:521-528.
- Barr J, et al. Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the Intensive Care Unit. Crit Care Med 2013;41:263-306.
- Brink P, et al. Advanced Design in Nursing Research.Thousand Oaks, CA: Sage Publications; 1998.
- Payen J, et al. Assessing pain in critically ill sedated patients by using a behavioral pain scale. Crit Care Med 2001;29:2258-2263.
- Gélinas C, et al. Item selection and content validity of the Critical-Care Pain Observation Tool for non-verbal adults. J Adv Nurs 2008;65:203-216.
- Gélinas C. Nurses’ evaluation of the feasibility and the clinical utility of the Critical-Care Pain Observation Tool. Pain Manage Nurs 2010;11:115-125.
- Keane K. Validity and reliability of the Critical-Care Pain Observation Tool: A replication study. Pain Manage Nurs 2013;14:
e216-e225. - Stites M. Observational pain scales in critically ill adults. Crit Care Nurs 2013;33:68-78.
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