Critical Appraisal of Pain Assessment Tools

Introduction

Patients presenting with acute pain in hospital settings need immediate intervention and care to improve health outcomes (Department of Health Service, 2007). When severe acute pain is not appropriately managed, this could lead to adverse psychological and physiological effects, poorer health outcomes and prolonged hospital stay (ANZCA, 2005). In Australia, approximately a third of patients in hospital settings report experiencing moderate to severe pain at least once during their hospital stay (DHS, 2007). While this figure may vary according to the population surveyed in hospital settings, it is observed that inadequate pain relief is still present in these settings (ANZCA, 2005).

Quality care for patients presenting with acute pain begins with the use of an appropriate pain assessment tool. The main aim of this essay is to critically review current pain assessment tools that are recommended by the Department of Health Services (DHS, 2007). Published primary studies will be used to support the critical analysis. The first part of this essay will compare a range of pain assessment tools for patients presenting with acute pain. The second part critically analyses pain assessment options for patients who are non-verbal, have significant cognitive impairment or language functions disability. A conclusion will then summarise the key issues raised in this essay.

Critical Analysis of Current Pain Assessment Tools

Pain assessment tools range from the use of subjective to objective pain-scoring assessment tools. Examples of subjective-pain scoring tools include the visual analogue scale (VAS), numerical rating scale (NRS) and the faces pain scale (FPS). Objective measures include the behavioural pain assessment scale,functional activity score and Abbey Pain Scale. Currently, VAS is one of the recommended tools for assessing acute pain in different groups of patients (DHS, 2007). Recent studies (Phan et al., 2012; Angthong, Cherchugit, Suntharapa, & Harnroongroj, 2011; Boonstra, SchiphorstPreuper, Reneman, Posthumus, & Stewart, 2008) have also shown its validity and reliability for different health conditions across different groups of patients and in various health care settings outside Australia. Apart from extensive published data on the reliability and validity of the VAS, it is also shown to be more sensitive when compared to descriptive pain scales (Boonstra et al., 2008).

Meanwhile, a randomised controlled trial (Farrar, Troxel, Stott, Duncombe, & Jensen, 2008) also shows the validity and reliability of the numeric rating scale not only in assessing acute pain but also in measuring spasticity of patients suffering from multiple sclerosis. This rating scale ranks pain from 1 to 10 or 0-11. However, it converts pain sensation to a number (Farrar et al., 2008). While it is conceptually straightforward, nurses have to explain its use to the patients. This tool is also language dependent. Hence, it is essential that non-English speaking patients should be assigned to nurses who speak the same language to reduce the risk of misunderstanding on the use of NRS.

Apart from VAS and NRS, FPS is also commonly used for pain assessment. One of the advantages of the FPS is its applicability in measuring pain intensity in paediatric patients. In the study of Tsze, von Baeyer, Bulloch and Dayan (2013) that recruited 620 patients aged 4 to 17 years old, FPS suggests strong psychometric properties for this age group. Importantly, this study shows that reliability and validity were also high between subgroups, sex, ethnicity and age of the children. Tsze et al. (2013) utilised the prospective, observational study involving Spanish and English-speaking children. Although this study design might increase the risk of observer bias due to its study design, a prospective study design is appropriate in validating the FPS (Polit, Beck &Hungler, 2013). While one of the advantages of FPS is its acceptability in younger and paediatric patients (Tsze et al., 2013), it could also be used for the elderly.

In Kim and Buschmann (2006), 31 older adults were recruited to determine the validity of the FPS. Findings suggest high construct validity and test-retest reliability of FPS. However, the small sample size of the study could limit the applicability of the findings to a larger and more heterogeneous population (Polit et al., 2013). As a whole, these subjective pain assessment tools have high inter class correlation. A study conducted amongst Chinese patients during post-operative care (Li, Liu & Herr, 2007) demonstrates high inter class correlation coefficients (ranging from 0.673 to 0.825) of VAS, FPS and NRS. This suggests

that healthcare practitioners can use any of these tools and arrive at a similar pain assessment score.

Meanwhile, objective measures for pain such as the behavioural pain assessment scale and functional activity score are used to assess pain of patients who are non-verbal or have suffered from cognitive impairment such as dementia (Husebo et al., 2008). However, this might increase the risk of rater bias (Hek, Judd & Moule, 2011) since nurses and other healthcare practitioners assess the pain level of the patient. Hence, it is important that inter-rater reliability and internal consistency of these tools should be established. A recent study (Voepel-Lewis, Zanotti, Dammeyer & Merkel, 2010) has shown the use of the Face, Legs, Activity, Cry, Consolability (FLACC) behavioural scale, which is similar to the behavioural pain assessment scale, as an effective tool for pain assessment in critically ill adults and children. It has excellent internal consistency (Cronbach alpha=0.882) and high inter-rater reliability.

Another objective pain assessment tool is the Abbey Pain Scale. This was developed to assess pain in patients with severe cognitive impairment such as those with severe dementia and non-verbal patients. Recent observational studies (Lukas, Barber, Johnson & Gibson, 2013; Neville & Ostini, 2013) demonstrated high validity and reliability of the Abbey Pain scale. In Neville and Ostini (2013), Abbey pain scale was compared with the Checklist of Nonverbal Pain Indicators Scale and Doloplus-2. Findings suggest that all scales showed good psychometric qualities. However, the Abbey Pain Scale is more applicable for nurse raters who demonstrate lower levels of nursing qualification. Neville and Ostini (2013) suggest that nurses who rarely use pain rating scales could use the Abbey Pain Scale while still maintaining inter-rater reliability.

Lukas et al. (2013) compared the Abbey Pain Scale with other pain assessment tools such as the Non-communicative Patient’s Pain Assessment Instrument (NOPPAIN) and the Pain Assessment in Advanced Dementia Scale (PAINAD). All these tools were validated to improve recognition of the presence or absence of pain. These tools were also useful in helping nurses rate the pain severity of older patients with dementia.

While pain assessment is a prerequisite for appropriate management of acute pain, there are some concerns about the use of pain intensity scoring systems. It has been shown that pain is subjective. This suggests that self-reporting of pain is variable and could be influenced by a host of factors. Studies (Narayan, 2010; Garcia, Godoy-Izquierdo, Godoy, Perez & Lopez-Chicheri, 2007) have shown that language, culture and psychological factors could all influence the perception of pain. Reynolds, Hanson, DeVellis, Henderson and Steinhauser (2008) explain that self-reporting of pain only provides healthcare practitioners an insight into how patients perceive their pain levels.

Variations in reporting of pain present a challenge to healthcare practitioners since this might lead to over or under-treatment of pain (Wilson, 2007). Other factors such as expectations of the patient in pain, the acceptability of translated tools and the methodology or terminology used during pain assessment might be foreign to the patients (Hall-Lord & Larsson, 2006). All these could influence reporting of pain. There is also the risk that observers might underestimate the pain (Wilson, 2007). Nurses’ knowledge on pain assessment is crucial since low levels of knowledge on pain assessment might affect how they assess the patient’s level of pain. Wilson (2007) argues that poor knowledge could lead to suboptimal care and poor pain management. This could have important consequences on patients since pain management might not be optimal. Hall-Lord and Larsson (2006) have stressed that pain assessment could be influenced by the nurses’ characteristics and knowledge of pain assessment. Lack of knowledge on pain assessment might lead to inaccurate pain assessment. In turn, this could lead to poor management and treatment of the underlying cause of pain. This also increases the risk of patients receiving inappropriate pain therapy (Wilson, 2007).

Conclusion

Pain assessment is important in managing acute pain in hospital settings. Various tools have been tested for their reliability and validity. These are divided into subjective and objective pain assessment tools. The former is generally used for patients who do not have cognitive impairments while the latter is used for patients with severe cognitive impairment and non-verbal patients. Studies cited in this essay have shown the validity and reliability of these tools. Studies that compare the subjective pain assessments also show high inter-correlation. This suggests that any of the tools could be used to assess pain. Despite extensive studies establishing the sensitivity, reliability and validity of the subjective tools, its application could still be limited. Pain is highly subjective and varies from one person to another. Objective tools might also be influenced by the nurses’ level of knowledge on pain assessment. Finally, this essay shows the need for nurses to increase their knowledge on pain assessment to ensure accurate assessment of pain.

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May Thu Khin, SID: 440468145, SNGP3001