Evaluation And Application Of Two Observational Pain Assessment Scales On Postoperative Pain Assessment During Recovery Period In Older Adults With Abdominal Surgery

BACKGROUDAs the population ages, the percentage of older adult patients receiving surgery increases. Abdominal surgery is one of the most common types of surgery in older adults. It is very important for older patients to have excellent surgical pain management, as the consequences of undertreated pain can be both complex and severe.Pain assessment is the first step of effective pain management. Patients’ self-report is the gold standard for pain assessment and there are many pain self-assessment scales with established reliability and validity. Among them, the Numeric Rating Scale (NRS), the Face Pain Scale-Revised (FPS-R), and the Iowa Pain Thermometer (IPT) have been demonstrated effective for postoperative pain assessment in Chinese older adults. However, it is more difficult to assess pain in the older adult patients because of more complex factors, such as more than one pain location, comorbidities, frailty, complications, and decline in cognitive function.The older adult patient having surgery will be affected by general anesthesia during recovery period, with cognitive ability for self-report further impaired and a high incidence of consciousness disturbances. So observational pain assessment tools (OPATs) are needed as part of the pain assessment process. Currently, there are more than twenty of OPATs that have been developed to assess pain in older persons, but few have been tested for use with acute pain post-surgery. Two tools, the Checklist of Nonverbal Pain Indicators (CNPI) and the Pain Assessment in Advanced Dementia (PAINAD), include items in line with the pain-related behaviors released by the American Geriatric Society (AGS) in2002. They are both easy to use with several language versions and proved to be transculturally effective. They were also used in hospices, hospitals and rehabilitation centers for dementia and cognitively intact Chinese older adults, but no research has been conducted in older adults during postoperatively recovery period. So research on the reliability and validity of the two scales during perioperative period is urgently needed.OBJECTIVESTo evaluate the reliability and validity of two observational pain assessment scales (Chinese version of the CNPI and the PAINAD) on postoperative pain assessment during recovery period in older adult patients with abdominal surgery under general anesthesia; and to explore the status of pain management during recovery and postoperative period, to provide evidence for quality surgical pain care for older adults.METHODS(A) Research instruments(1) OPATsCNPI:The CNPI was designed by Feldt KS, including six items of vocal complaints (non-verbal), facial grimaces/winces, bracing, restlessness, rubbing(massaging affected area), and the vocal complaints (verbal). Score a0if the behavior was not observed, and a1if the behavior occurred even briefly during activity or rest, with subtotal score of6(for both observation at rest and then on movement), for a total of12.PAINAD:The PAINAD was designed by Warden V., et al., including five items of breathing, negative vocalization, facial expression, body language and consolability, on which the severity of the behavior is rating on a0-2scale, for a total of10points possible.(2) Self-report pain intensity scalesNRS. The NRS is a10cm horizontal line with numbers0through10representing different degrees of pain intensity. Patients are asked to select the number that best represents their pain intensity.FPS-R. The FPS was revised by Hicks CL, et al., as the FPS-R in2001, consisting of six line-drawn faces scored0to10, presented in a horizontal format, and ranging from a neutral face to a grimacing face. Participants are instructed to point to the face that best represents the intensity of their pain.IPT. The IPT, developed by Herr K, is a modified Verbal Descriptors Scale (VDS) consisting of seven pain descriptors for different levels of pain intensity (from no pain to the most intense pain imaginable) plus response options between words (scores from0to12). The word scale is aligned with a thermometer to help with understanding the conceptualization of pain intensity.(B) Research participantsNinty-three patients aged60years and older admitted for scheduled abdominal surgery under general anesthesia in a large teaching hospital.(C) Research procedures(1) Preoperative visitAfter informed consents were obtained, patients were taught how to use selected pain scales to rate their pain intensity. Three pain assessment tools, the NRS, the FPS-R, and the IPT, were provided for the patients to choose from the one they preferred to use. All patients could use at least one preferred scale to accurately report their pain intensity. Information regarding patient’s age, gender and ASA (American Society of Anesthesiologists) score were then collected.(2) Pain assessment during recovery periodThe CNPI and the PAINAD were used to conduct pain assessments during the post-operative recovery period. Patients’self-report score of current pain during recovery (SSCPR) were also obtained at the same time. Operation start time and end time were documented and the operation duration time was calculated. The inter-rater consistency was evaluated during this period. Two trained nurses at the recovery room both used the two scales, simultaneously observing another20older adult patients with abdominal surgery under general anesthesia during recovery period, respectively, to establish interrater consistency.(3) Post-operative visitsParticipants were visited on the first and the third postoperative day. Their current pain and the earliest recalled postoperative pain intensity that he or she could remember were assessed using one of the above three self-report scales each time, noted by S1(Score of Current Pain Intensity on the First Postoperative Day), S1-R (Score of Recalled Pain Intensity on the First Postoperative Day), S2(Score of Current Pain Intensity on the Third Postoperative Day), S2-R (Score of Recalled Pain Intensity on the Third Postoperative Day), respectively.(D) Data analysisAll data were entered, categorized and statistically analyzed by SPSS16.0.General information and pain scores were analyzed using descriptive statistical analysis. Cronbach’s alpha coefficient was used to evaluate the internal consistency reliability of the CNPI and the PAINAD. Criterion validity was evaluated through analysis of correlations between the CNPI and the PAINAD scale scores and scores of patients’self-report in recovery period and two recalled scores on the first and the third postoperative day. Predict effectiveness of the two scales on postoperative pain intensity was evaluated by correlation analysis between the two scores and the two postoperative pain scores. The inter-rater consistency was analyzed using correlation coefficient.RESULTSIn93patients,57(61.29%) were males, and36(38.71%) were females, with the mean age of68.05±7.31years old (ranged from60to95) years old, and the mean operative time of3.18±2.18(ranged from0.75to12.08) hours.1. Internal consistency reliabilityThe Cronbach’s alpha coefficient of the CNPI and the PAINAD were0.68and0.81, respectively, and the Spearman correlation coefficient of the two scale scores was rp=0.95.2. Pain scores during the recovery period(1) Criterion validity of the two scalesThe mean self-report score of current pain intensity during recovery (SSCPR) was1.85±2.49(ranged from0to8), the mean CNPI score2.78±2.17(ranged from0to9), the mean PAINAD score was2.15±1.94(ranged from0to8), the mean recalled pain score on the first postoperative day (S1-R) was2.99±2.71(ranged from0to9), and the mean recalled pain score on the third postoperative day (S2-R) was2.89±2.62(ranged from0to9). Spearman correlation analysis were conducted between the CNPI scores and three pain intensity ratings during recovery period (SSCPR, S1-R and S2-R), with the results of rp=0.74,0.60,0.60, respectively, with P <0.001. The same analyses were done for the PAINAD scores, with the results of rp=0.69,0.55,0.54, respectively, with P <0.001. The Spearman correlation coefficient rp between S1-R and S2-R was0.99, P<0.001.(2) The inter-rater consistency Inter-rater consistency was established in a sample of20patients,11(55%) males, and9(45%) females, with the mean age of66.90±6.90years old (ranged from60to83), and mean operative time of2.87±1.71hours (ranged from0.75to6.50). The result of bivariate correlation analysis of the CNPI scores assessed by two research assistants on the same patient at the same time was r=0.69. The result of the same analysis on the PAINAD was r=0.73.3. Predict effectiveness of the two scales on postoperative pain intensityThe mean pain score on the first postoperative day (S1) was4.60±2.42(ranged from0to10), and the mean pain score on the third postoperative day (S2) was2.72±1.78(ranged from0to8). Spearman correlation analyses were conducted between the CNPI scores and the two postoperative pain scores (S1and S2), with results of rp=0.66,0.60; and results for the PAINAD were rp=0.57,0.50; P <0.001both.4. Potential impacting factors of pain scoresGender was not correlated with all pain scores. Age was only correlated with patients’ASA grading (rp=0.33, P=0.001).The duration of surgery was correlated with patients’ASA grading (rp=0.25, P=0.017), and with all pain scores, rp ranging from0.37(S2) to0.21(PAINAD), P=0.00to0.042. ASA grading was correlated with patients’age, operative time, and all pain scores, except the CNPI and the PAINAD, with rp ranging from0.30to0.24, P=0.004to0.021.5. Postoperative pain management statusFindings from medical and nursing records of the93older adults with abdominal surgery showed that60.22%of nurses’and61.29%of doctors’ records described their postoperative pain situation, and58.06%of these older adult patients were administered analgesics, including improper usage of intramuscular injection of Meperidine (Demerol). CONCLUSIONS1. Both the CNPI and the PAINAD had good reliability, validity and inter-rater consistency when used to assess pain in older adult patients with abdominal surgery during recovery period after general anesthesia. The PAINAD was better than the CNPI in internal consistency reliability and inter-rater consistency, and the CNPI had better criterion validity than the PAINAD.2. Accurate usage of two scales could predict postoperative pain in older adult patients to some extent. Observational pain scales can be a backup tool for those who can’t self report. With observational pain assessment scales to evaluate patients’pain during recovery period, postoperative pain care could be planned ahead to the anesthetical recovery period, which would be helpful to improve the quality of postoperative pain management.3. The pain management during recovery period in older adult patients undergoing abdominal surgery was good, but the postoperative pain control was unsatisfactory, and the quality of pain care for surgical older adult patients needed to be improved.In summary, the Chinese version of the CNPI and the PAINAD could be used for postoperative pain assessment during recovery period in older adult patients with abdominal surgery under general anesthesia who are unable to provide self-report, and could predict postoperative pain intensity to some extent. We suggest that the two scales be used properly in daily clinical practice to provide more evidence for pain assessment and management for those unable to communicate.