The Effect of Preoperative Pregabalin on Postoperative Nausea and Vomiting: A Meta-analysis

Grant, M. et al. (2016) Anesthesia & Analgesia123(5) pp. 1100–1107


Background: Nonopioid adjuvant medications are increasingly included among perioperative Enhanced Recovery After Surgery protocols. Preoperative pregabalin has been shown to improve postoperative pain and limit reliance on opioid analgesia. Our group investigated the ability of preoperative pregabalin to also prevent postoperative nausea and vomiting (PONV).

Methods: Our group performed a meta-analysis of randomized trials that report outcomes on the effect of preoperative pregabalin on PONV endpoints in patients undergoing general anesthesia.

Results: Among all included trials (23 trials; n = 1693), preoperative pregabalin was associated with a significant reduction in PONV (risk ratio [RR] = 0.53; 95% confidence interval [CI], 0.39–0.73; P = 0.0001), nausea (RR = 0.62; 95% CI, 0.46–0.83; P = 0.002), and vomiting (RR = 0.68; 95% CI, 0.52–0.88; P = 0.003) at 24 hours. Subgroup analysis designed to account for major PONV confounders, including the exclusion trials with repeat dosing, thiopental induction, nitrous oxide maintenance, and prophylactic antiemetics and including high-risk surgery, resulted in similar antiemetic efficacy. Preoperative pregabalin is also associated with significantly increased rates of postoperative visual disturbance (RR = 3.11; 95% CI, 1.34–7.21; P = 0.008) compared with a control.

Conclusions: Preoperative pregabalin is associated with significant reduction of PONV and should not only be considered as part of a multimodal approach to postoperative analgesia but also for prevention of PONV.

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Haemodynamic effects of parenteral vs. enteral paracetamol in critically ill patients: a randomised controlled trial

Kelly, S.J. et al. (2016) Anaesthesia. 71. pp. 1153-62


Introduction: Reports in the literature have suggested that paracetamol is associated with significant hypotension, a potentially important interaction for labile critically ill patients. These authors carried out a single-centre, prospective, open-label, randomised, parallel-arm, active-control trial, designed to determine the incidence of hypotension following the administration of paracetamol to critically ill patients.

Methods: A total of 50 adult patients receiving paracetamol for analgesia or pyrexia were randomly assigned to receive either the parenteral or enteral formulation of the drug. Paracetamol concentrations were measured at baseline and at multiple time points over 24 hours.

Results: The maximal plasma paracetamol concentration was significantly different between routes; 156 versus 73 µmol/L (p=0.0005) following the first dose of parenteral or enteral paracetamol, respectively. Sixteen hypotensive events occurred in 12 patients: parenteral n=12; enteral n=4. The incident rate ratio for parenteral versus enteral paracetamol was 2.94 (95% confidence interval 0.97 to 8.92; p=0.06).

Conclusions: The authors conclude that the incidence of hypotension associated with paracetamol administration is higher than previously reported and tends to be more frequent with parenteral paracetamol.

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Rethinking training in airway management

Marshall, S. D. & Chrimes, N. Time for a breath of fresh air: Rethinking training in airway management. Anaesthesia. published online 28 September 2016.

In this editorial, Marshall and Chrimes  suggest that the way in which anaesthetists  conceptualise ‘airway education’ needs to change. They go on to say that while the last two decades of anaesthetic practice have seen a the proliferation of airway devices and techniques, training and maintaining skills in airway management have not necessarily kept pace.

In summary, they write that if anaesthetists are to continue to be regarded as airway management experts, a fundamental shift must occur in both the way they train and retain their skills.

This editorial accompanies an article by Lindkær-Jensen et al., Anaesthesia 2016; 71: doi: 10.1111/anae.13567, A national survey of practical airway training in UK anaesthetic departments. Time for a national policy?

Management of pain in the terminally ill

King, S.E. et al. Anaesthesia & Intensive Care Medicine. Published online: 23 September 2016

drug-1674890_960_720Pain management in the terminally ill can be complex and challenging necessitating a holistic approach. Multimodal analgesic strategies are usually employed to successfully manage pain and other symptoms. There are now a variety of opioid formulations available to treat moderate to severe pain. Neuropathic and cancer-induced bone pain can be difficult to treat, but newer drugs are available in addition to a number of established interventional procedures. The psychosocial aspects associated with terminal illness must be considered and managed with the involvement of a multidisciplinary palliative care team.

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Anesthesia Technique and Mortality after Joint Replacement

Perlas, A; Chan, V. W.S; & Beattie, S.  Anesthesia Technique and Mortality after Total Hip or Knee Arthroplasty: A Retrospective, Propensity Score–matched Cohort Study. Anesthesiology  October 2016, Vol.125, 724-731

Background: This propensity score–matched cohort study evaluates the effect of anesthetic technique on a 30-day mortality after total hip or knee arthroplasty.

Methods: All patients who had hip or knee arthroplasty between January 1, 2003, and December 31, 2014, were evaluated. The principal exposure was spinal versus general anesthesia. The primary outcome was 30-day mortality. Secondary outcomes were (1) perioperative myocardial infarction; (2) a composite of major adverse cardiac events that includes cardiac arrest, myocardial infarction, or newly diagnosed arrhythmia; (3) pulmonary embolism; (4) major blood loss; (5) hospital length of stay; and (6) operating room procedure time. A propensity score–matched-pair analysis was performed using a nonparsimonious logistic regression model of regional anesthetic use.

Results: We identified 10,868 patients, of whom 8,553 had spinal anesthesia and 2,315 had general anesthesia. Ninety-two percent (n = 2,135) of the patients who had general anesthesia were matched to similar patients who did not have general anesthesia. In the matched cohort, the 30-day mortality rate was 0.19% (n = 4) in the spinal anesthesia group and 0.8% (n = 17) in the general anesthesia group (risk ratio, 0.42; 95% CI, 0.21 to 0.83; P = 0.0045). Spinal anesthesia was also associated with a shorter hospital length of stay (5.7 vs. 6.6 days; P < 0.001).

Conclusions: The results of this observational, propensity score–matched cohort study suggest a strong association between spinal anesthesia and lower 30-day mortality, as well as a shorter hospital length of stay, after elective joint replacement surgery.

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Publication Bias and Nonreporting Found in Majority of Systematic Reviews and Meta-analyses in Anesthesiology Journals

Hedin, R. et al. (2016) Anesthesia & Analgesia. 123(4) pp.1018–1025

Background: Systematic reviews and meta-analyses are used by clinicians to derive treatment guidelines and make resource allocation decisions in anesthesiology. One cause for concern with such reviews is the possibility that results from unpublished trials are not represented in the review findings or data synthesis. This problem, known as publication bias, results when studies reporting statistically nonsignificant findings are left unpublished and, therefore, not included in meta-analyses when estimating a pooled treatment effect. In turn, publication bias may lead to skewed results with overestimated effect sizes. The primary objective of this study is to determine the extent to which evaluations for publication bias are conducted by systematic reviewers in highly ranked anesthesiology journals and which practices reviewers use to mitigate publication bias. The secondary objective of this study is to conduct publication bias analyses on the meta-analyses that did not perform these assessments and examine the adjusted pooled effect estimates after accounting for publication bias.

Methods: This study considered meta-analyses and systematic reviews from 5 peer-reviewed anesthesia journals from 2007 through 2015. A PubMed search was conducted, and full-text systematic reviews that fit inclusion criteria were downloaded and coded independently by 2 authors. Coding was then validated, and disagreements were settled by consensus. In total, 207 systematic reviews were included for analysis. In addition, publication bias evaluation was performed for 25 systematic reviews that did not do so originally. We used Egger regression, Duval and Tweedie trim and fill, and funnel plots for these analyses.

Results: Fifty-five percent (n = 114) of the reviews discussed publication bias, and 43% (n = 89) of the reviews evaluated publication bias. Funnel plots and Egger regression were the most common methods for evaluating publication bias. Publication bias was reported in 34 reviews (16%). Thirty-six of the 45 (80.0%) publication bias analyses indicated the presence of publication bias by trim and fill analysis, whereas Egger regression indicated publication bias in 23 of 45 (51.1%) analyses. The mean absolute percent difference between adjusted and observed point estimates was 15.5%, the median was 6.2%, and the range was 0% to 85.5%.

Conclusions: Many of these reviews reported following published guidelines such as PRISMA or MOOSE, yet only half appropriately addressed publication bias in their reviews. Compared with previous research, our study found fewer reviews assessing publication bias and greater likelihood of publication bias among reviews not performing these evaluations.

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Internet-Based Resources Frequently Provide Inaccurate and Out-of-Date Recommendations on Preoperative Fasting: A Systematic Review.

Roughead, T. et al. Anesthesia & Analgesia. Published online: September 16 2016


Preoperative fasting is important to avoid morbidity and surgery delays, yet recommendations available on the Internet may be inaccurate. Our objectives were to describe the characteristics and recommendations of Internet resources on preoperative fasting and assess the quality and readability of these websites.

We searched the Internet for common search terms on preoperative fasting using Google(R) search engines from 4 English-speaking countries (Canada, the United States, Australia, and the United Kingdom). We screened the first 30 websites from each search and extracted data from unique websites that provided recommendations on preoperative fasting. Website quality was assessed using validated tools (JAMA Benchmark criteria, DISCERN score, and Health on the Net Foundation code [HONcode] certification). Readability was scored using the Flesch Reading Ease score and Flesch-Kincaid Grade Level.

A total of 87 websites were included in the analysis. A total of 48 websites (55%) provided at least 1 recommendation that contradicted established guidelines. Websites from health care institutions were most likely to make inaccurate recommendations (61%). Only 17% of websites encouraged preoperative hydration. Quality and readability were poor, with a median JAMA Benchmark score of 1 (interquartile range 0-3), mean DISCERN score 39.8 (SD 12.5), mean reading ease score 49 (SD 15), and mean grade level of 10.6 (SD 2.7). HONcode certification was infrequent (10%). Anesthesia society websites and scientific articles had higher DISCERN scores but worse readability compared with websites from health care institutions.

Online fasting recommendations are frequently inconsistent with current guidelines, particularly among health care institution websites. The poor quality and readability of Internet resources on preoperative fasting may confuse patients.

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