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The Effects of Postoperative Pain and Its Management on Postoperative Cognitive Dysfunction

https://doi.org/10.1097/01.JGP.0000229792.31009.daGet rights and content

To determine risks for postoperative cognitive dysfunction (POCD), the authors conducted a prospective cohort study of 225 patients ≥65 years of age undergoing noncardiac surgery. Cognitive testing using the Word List, Verbal Fluency, and Digit Symbol tests was conducted for each patient preoperatively and 1 and 2 days postoperatively in patients without postoperative delirium. POCD was defined as meeting statistical criteria for decline from the patient's preoperative performance levels on at least two of the three cognitive tests. Multivariate logistic regression analysis determined the association between pain and postoperative analgesia with POCD after controlling for demographics, comorbidities, preoperative level of cognitive and daily functioning, preoperative medications, duration and type of anesthesia, and adverse events. Patients were on average 72 years old and 13% of patients experienced POCD on day 1, 7% on day 2, and 15% had POCD on either day 1 or day 2 after the surgery. Multivariate regression analyses revealed that only postoperative analgesia was associated with the development of POCD. Compared with those receiving postoperative analgesia through a patient-controlled analgesia device that administered opioids intravenously, those who received postoperative analgesia orally were at significantly lower risk for the development of POCD (odds ratio: 0.22; 95% confidence interval: 0.06–0.80; Wald chi-square = 5.36, df = 1, p = 0.02). Older patients undergoing noncardiac surgery who are not delirious can experience significant declines in cognitive functioning postoperatively. Those at least risk of experiencing POCD were those who received postoperative analgesia orally.

Section snippets

Patient Recruitment

Patients included in this study are a subset from a larger ongoing study evaluating the effect of type of anesthesia on perioperative outcomes in elderly surgical patients (Table 1). The sample consisted of nondelirious patients who underwent noncardiac surgery. The study was conducted from 2001–2004 at one of the teaching hospitals at the University of California, San Francisco (UCSF). The study received approval from the Institutional Review Board for human research at UCSF and Purdue

RESULTS

The 225 nondelirious patients included in this study had a mean age of 72.4 ± 7.6 years, 86% were white, 43% were female, and 21% received no greater than high school education. Approximately 26% patients underwent hip and knee replacement surgery, 22% other orthopedic surgery (nonintracranial, surgery of the spine), followed by urologic (21%), gynecologic (9%), or vascular (9%) surgery. Preoperatively, 46% of patients were classified as ASA class ≥3, and 67% were independent in all seven

DISCUSSION

This study revealed that patients who receive postoperative analgesia orally are significantly less likely to experience POCD. Prior studies revealed that POCD is associated with declines in daily functioning three months after surgery,4, 5, 6, 7, 8, 9, 10, 11, 12, 13 so it is important to identify treatment factors that increase a patient's risk for experiencing POCD. Although prior studies have identified risks for POCD4, 12, 13, 14, 15, 17, 39 they have not focused on whether postoperative

CONCLUSIONS

Fifteen percent of nondelirious older patients undergoing noncardiac surgery experienced POCD. Compared with other forms of postoperative analgesia methods, patients using oral analgesics to control postoperative pain were at significantly lower risk for experiencing POCD.

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  • Cited by (0)

    Supported by NIH grants AG-022090 and K24 AG00948 to L. Sands and J. Leung, respectively.

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