Age as a predictor of rescue opioid administration immediately after the emergence of general anesthesia

Is Prevention of Postoperative Vomiting Surgery Dependent? A Retrospective Cohort Study of Total Knee Arthroplasty

The study of postoperative nausea and vomiting (PONV) has been ongoing since the early days of general anesthesia. The search for risk factors of PONV and the development of new agents to treat PONV are the two main strategies to combat the adverse side effects of general anesthesia. Female sex, non-smoking status, a history of PONV/motion sickness, and postoperative opioid use are the four independent risk factors for PONV derived after a series of prospective studies, evidence-based systematic reviews, and meta-analyses. The two frequently asked questions that arise ask whether risk factors apply to different clinical settings and whether prevention measures of PONV can be surgery dependent. We conducted a comprehensive review of 665 patients who underwent primary total knee arthroplasty (TKA) between January and December 2019. As nausea is subjective and its measurement is not standardized, postoperative vomiting (POV) was used as a study endpoint. The exclusion criteria were desflurane anesthesia, spinal anesthesia, anesthesia without bispectral index monitoring, and day surgery. Three well-recognized risk factors, consisting of body weight, sevoflurane consumption, and postoperative opioid consumption, were not considered as independent risk factors of POV, while female sex, preoperative adductor canal block (ACB), and dexamethasone were identified as being so in this study. The risk of POV in the female sex was 2.49 times that in the male sex; however, when dexamethasone was used, this risk was reduced by >40% compared with no antiemetic use, and by >50% when patients received preoperative ACB compared with those without the block. The clinical characteristics of our TKA patients—female dominance, old age, and their fairly constant body weights that were distinct from those of other surgical patients—suggested that age may play a crucial role in determining the relative contributions of the different risk factors of POV. We concluded that risk factors of POV are dependent on clinical settings. Based on these results, it is reasonable to speculate that a surgery-dependent plan for the prevention of POV is feasible for patients in similar clinical settings.

Prospective randomized trial of continuous femoral nerve block with posterior capsular injection versus periarticular injection for analgesia in primary total knee arthroplasty

Background:

Femoral nerve block (NB) and periarticular injection (PI) are 2 common options for pain control after total knee arthroplasty (TKA). We performed a prospective triple-blinded randomized trial comparing continuous femoral NB to PI, with follow-up to 1 year.

Methods:

Patients younger than 70 years of age who were scheduled to undergo elective primary TKA under spinal anesthesia between 2009 and 2010 were randomly allocated to receive either continuous femoral NB or PI. Patients in the NB group received ropivacaine through an NB catheter and a sham saline PI. The PI group received a PI of ropivacaine, morphine, ketorolac and epinephrine, and a sham saline infusion via an NB catheter. Both groups had standardized oral analgesia preoperatively, spinal anesthesia and sedation, and postoperative analgesia. Surgeons, anesthesiologists, patients and assessors were blinded to group assignment. Pain was measured twice daily on postoperative days 1 and 2, at rest and with motion, with a numeric rating scale. Patient satisfaction, pain (Oxford Knee Score) and range of motion were assessed at 1 year.

Results:

There were 39 participants in the NB group and 35 participants in the PI group. There were no statistically significant differences between the groups at baseline. Statistically but nonclinically significant reductions in pain scores on postoperative day 2 and in narcotic need on the day of surgery were found in the PI group. Patient-reported satisfaction did not differ at any time point. At 1 year, knee flexion was significantly greater in the NB group than in the PI group (mean range of motion 120° v. 110°, p = 0.03).

Conclusion:

There was no demonstrated improvement in pain control with the use of an NB versus PI when used with multimodal analgesia. Clinicians should opt for the modality that has the best efficiency for their surgical environment. ClinicalTrials.gov # NCT00869037

A Narrative Review of the Evidence on the Efficacy of Dexamethasone on Postoperative Analgesic Consumption

OBJECTIVES

The effect of dexamethasone on analgesic consumption has not been adequately studied. The aim of this review was to investigate recent literature regarding the possible effect of dexamethasone on postoperative analgesic consumption.

METHODS

Critical review of randomized trials and prospective consecutive studies investigating the postoperative analgesic effect of dexamethasone was performed. Only studies published during 2006 to 2015 were included.

RESULTS

Forty-one studies met the inclusion criteria; 33 in adults and 8 in children (9 in general surgery, 8 in gynecologic/breast surgery, 8 in orthopedic/spinal surgery, 8 in head/neck surgery, 7 in children's tonsillectomy, and 1 in children's orchiopexy). Literature review demonstrated that dexamethasone can decrease analgesic requirements in patients undergoing laparoscopic cholecystectomies, laparoscopic gynecologic and breast surgery; whereas there is no consensus regarding orthopedic procedures, with positive evidence mostly regarding spinal surgeries. The efficacy of dexamethasone during head and neck surgery is not conclusive; however, its use before thyroid surgery may be beneficial. In children a beneficial impact of dexamethasone administration was revealed on posttonsillectomy reduction of analgesic needs. Studies on other kinds of operations in children are lacking.

CONCLUSIONS

Dexamethasone administered at a dose of 8 mg before surgical incision may be beneficial in laparoscopic cholecystectomies, thyroid, laparoscopic gynecologic and breast surgery, and tonsillectomies in children. Dexamethasone's potential impact on reducing postoperative analgesic requirements should be investigated in more detail in a systematic manner, to support its use in other kinds of operations.

Pharmacotherapy of Pain in the Older Population: The Place of Opioids

Pain is a common symptom in older people. It is possible that pain is underreported in older persons due to an incorrect belief that it is an inevitable part of aging. Opioid analgesics are potent medications, with confirmed efficacy for the treatment of moderate to severe pain. These drugs are commonly used in older persons. However, there is insufficient evidence regarding safety of opioids in older patients. One of the reasons for this is the lack of randomized, controlled clinical trials. People of advanced age often have comorbidites and use other prescription drugs, as well as over-the-counter (OTC) compounds, thus making them more suceptible to the risk of interactions with opioids. Significant pharmacokinetic and pharmacodynamic changes that occur with advancing age increase the risk of adverse effects of opioids. There are also some discrepancies between guidelines, which recommend the use of lower doses of opioids in older patients, and the findings in the literature which suggest that pain is often undertreated in this age group. It seems that there are significant variations in the tolerability of different opioid analgesics in older people. Morphine, fentanyl, oxycodone, and buprenorphine are still the preferred evidence-based choices for add-on opioid therapy for these patients. However, the safety and efficacy of other opioids in older patients, especially if comorbidities and polypharmacy are present, is still questionable. This review addresses the most important aspects of the use of opioids in older persons, focusing on pharmacokinetics, pharmacodynamics, adverse effects, and interactions.