Original contribution
A comparison of postoperative cognitive function and pain relief with fentanyl or tramadol patient-controlled analgesia

https://doi.org/10.1016/j.jclinane.2005.08.004Get rights and content

Abstract

Study Objective

The use of different opioids for patient-controlled analgesia (PCA) may affect postoperative cognitive function differently. Patient-controlled analgesia fentanyl has been shown to preserve cognitive function better than morphine. The effect of PCA tramadol on cognitive function is unknown. This study aims to compare postoperative cognitive function and analgesia of PCA fentanyl or tramadol.

Design

Prospective randomized double-blinded study.

Setting

Metropolitan teaching hospital.

Patients

30 ASA physical status I, II, and III patients undergoing lower abdominal operations.

Interventions

Patients received standard general anesthesia for their operations. Postoperatively, patients received either fentanyl (group F, 10 μg bolus, n = 17) or tramadol (group T, 20 mg bolus, n = 13) for PCA. Group F patients also received fentanyl boluses and group T patients received tramadol boluses intraoperatively.

Measurements

Cognitive function was measured using Mini-Mental State Examination and Benton Visual Retention Test (BVRT) preoperatively and on days 1 and 2. Pain was measured by numerical rating scale.

Results

No differences were found in postoperative Mini-Mental State Examination or BVRT scores, but significantly fewer (29.4%; 95% confidence interval [CI], 13.3%-53.1%) group F patients were able to complete BVRT compared with group T patients (84.6%; 95% CI, 57.8%-95.7%; 95% CI of difference, 19.4%-74.8%) (P = 0.010) on day 1. In the first 24 hours, group F and group T patients had similar analgesia at rest, but group T patients had better analgesia during cough (mean Numeric Rating Scale, 7.6; 95% CI, 7.0-8.2 vs 6.0; 95% CI, 4.8-7.2, group F vs group T) (P = 0.018; 95% CI of difference, 0.4-2.8). No differences were found in frequency of side effects or patient satisfaction.

Conclusions

Tramadol or fentanyl PCA has similar cognitive effects on days 1 and 2; however, patients receiving tramadol PCA are more motivated to undergo cognitively demanding tasks and have slightly better analgesia on postoperative day 1.

Introduction

Intravenous patient–controlled infusion of opioids (patient-controlled analgesia [PCA]) is a popular and effective analgesic technique. Little data are available on the effect of different opioids on cognitive function of patients while on PCA. Morphine was reported to preserve cognitive function better than hydromorphone in one study, [1] and fentanyl was reported to be superior to morphine in a second study. [2] Based on these limited data, it seems fentanyl might be the opioid of choice for PCA as far as preservation of cognitive function is concerned.

Tramadol is a centrally acting analgesic showing promise in a few areas including less sedation, less respiratory depression, and less euphoria, compared with other opioids [3], [4], [5], [6]. Although it is less sedating, it is not known whether the cognitive function of patients receiving tramadol for postoperative PCA may also be better preserved compared with other opioids.

The aim of the study was to compare the effect on cognitive function and the analgesic efficacy of PCA tramadol vs PCA fentanyl, the preferred “conventional” opioid.

Section snippets

Materials and methods

The study was commenced after approval from the University of Hong Kong Faculty of Medicine ethics committee. This was a prospective, randomized, double-blind study. Only adult Cantonese-speaking Chinese patients scheduled for elective colorectal operations and who accepted PCA for postoperative analgesia were recruited. All patients were ASA physical status I, II, or III. Written, informed consent was obtained. Patients with known allergy to any component of perioperative anesthetic

Results

Thirty-one patients satisfied the criteria of inclusion and were randomized into two groups. One patient was excluded early because his preoperative BVRT test result was found missing, and therefore, only 30 patients were analyzed. Seventeen patients were randomized to group F and 13 to group T. The demographic data are summarized in Table 1.

For patients who could complete all the tests postoperatively, no significant differences in MMSE or BVRT scores were detectable between the two groups at

Discussion

Our study found that significantly more patients receiving tramadol PCA than fentanyl PCA were able to complete cognitively demanding tasks on the first postoperative day; however, we could not demonstrate superior cognitive function test scores in those receiving tramadol PCA.

Postoperative cognitive impairment is common, particularly in elderly patients [12]. Many factors contribute to its development [13]. Postoperative cognitive impairment is also associated with postoperative delirium [14],

Acknowledgments

This study was supported by a CRCG Research Grant from the University of Hong Kong (Acc Code 10202116/26981/20100/323/01). The authors thank Dr SL Tsui and members of the Division of Pain Medicine, Department of Anaesthesiology, Queen Mary Hospital, for their advice and support in this study. The authors also thank Ms Jeff Man for assistance with conduct of MMSE and BVRT and with statistical analysis.

References (23)

  • J.M. Unger et al.

    Cross-sectional versus longitudinal estimates of cognitive change in nondemented older people: a CERAD study. Consortium to Establish a Registry for Alzheimer's Disease

    J Am Geriatr Soc

    (1999)
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      They recognized that delirium and/or cognitive impairment are common adverse events that affect morbidity and postoperative recovery and the limitations of the papers reviewed (e.g. small sample sizes and non-standardized measurement of cognitive impairment), and they recommended future studies of postoperative cognitive impairment in patients given postoperative opioids. In another study postoperative cognitive function was assessed after patient-controlled analgesia in 30 patients undergoing lower abdominal surgery, who received either fentanyl (n = 17) or tramadol (n = 13) intraoperatively and postoperatively (6c). Cognitive function was assessed on days 1 and 2 using the Mini Mental State Examination and the Benton Visual Retention Test.

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    This study was supported by a CRCG Research Grant from the University of Hong Kong (Acc Code 10202116/26981/20100/323/01), Hong Kong, China.

    1

    Current address: Department of Anaesthesiology, Grantham Hospital, Hong Kong, China.

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