Opioid use in knee arthroplasty after receiving intravenous acetaminophen.

BACKGROUND: Intravenous (IV) acetaminophen may be an effective component of multimodal postoperative pain management. The primary objective of this study was to evaluate the impact of IV acetaminophen on total opioid use in postoperative patients. The secondary objective was to evaluate the effect of IV acetaminophen on hospital length of stay. METHODS: This retrospective, case-control study evaluated the impact of IV acetaminophen on total opioid use in surgical patients. Patients were included if they received at least one perioperative dose of IV acetaminophen and underwent a surgical knee procedure. Controls were matched and randomly selected based on procedure type, age, and severity of illness. Postoperative opioids were converted into oral morphine equivalents, and overall use was compared between groups. RESULTS: One hundred patients were enrolled, with 25 patients receiving IV acetaminophen and 75 matched controls. A total of 135 mg versus 112.5 mg oral morphine equivalents were used in the IV acetaminophen group and control group, respectively (p=0.987). There were 45 mg/day oral morphine equivalents used in the IV acetaminophen group versus 37.5 mg in the control group (p=0.845). The median hospital length of stay in both groups was 3 days (p=0.799). CONCLUSION: IV acetaminophen did not significantly decrease postoperative opioid use in patients who underwent surgical knee procedures. In addition, there was a nonsignificant trend toward increased opioid use in the IV acetaminophen group. There was no significant difference in hospital length of stay between the IV acetaminophen group and the control group. These findings require further study in larger patient populations and in other orthopedic procedures that typically require longer hospital stays.

Comparison of two instruments for assessing risk of postoperative nausea and vomiting.

PURPOSE: Two instruments for assessing patients' risk of postoperative nausea and vomiting (PONV) were compared. METHODS: The existing protocol (protocol 1) assessed PONV risk using 16 weighted risk factors and was used for both adults and pediatric patients. The new protocol (protocol 2) included a form for adults and a pediatric-specific form. The form for adults utilized the simplified risk score, calculated using a validated, nonweighted, 4-point scale, and categorized patients' risk of PONV as low, moderate, or high. The form for pediatric patients used a 7-point, non-weighted scale and categorized patients' risk of PONV as moderate or high. A list was generated of all patients who had surgery during August 2005, for whom protocol 1 was used, and during April 2006, for whom protocol 2 was used. Fifty patients from each time period were randomly selected for data analysis. Data collected included the percentage of the form completed, the development of PONV, the number of PONV risk factors, patient demographics, and the appropriateness of prophylaxis. RESULTS: The mean +/- S.D. number of PONV risk factors was significantly lower in the group treated according to protocol 2 ( p = 0.001), but fewer patients in this group were categorized as low or moderate risk and more patients were identified as high risk (p < 0.001). More patients assessed by protocol 2 received fewer interventions than recommended (p < 0.001); however, the frequency of PONV did not significantly differ between groups. CONCLUSION: Implementation of a validated and simplified PONV risk-assessment tool appeared to improve form completion rates and appropriate risk assessment; however, the rates of PONV remained similar and fewer patients received appropriate prophylaxis compared with patients assessed by the existing risk-assessment tool.