This Week in Anesthesiology — Sep 7, 2026

Welcome to This Week in Anesthesiology. This week we're covering 10 notable papers spanning sedation and anaesthetic pharmacology, opioid-sparing analgesia and recovery after surgery, and risk stratification in older surgical patients. Let's dive in.

We'll start with the drugs we give every day. In Critical Care Medicine, Casamento and colleagues report a double-blind, placebo-controlled randomised trial of low-dose ketamine as an adjunct for analgosedation in mechanically ventilated adults across two Melbourne intensive care units [1]. A hundred and twenty patients received either a ketamine infusion at 0.15 milligrams per kilogram per hour or placebo alongside their opioid infusion. The median hourly opioid requirement fell by about 13 micrograms of fentanyl equivalents per hour with ketamine, roughly a sixth less than placebo, and the Bayesian analysis put the probability of benefit at around 95 percent. That said, the credible interval crossed zero, and there was no signal of difference in delirium, ventilator-free days, or serious adverse events. So the honest read is that low-dose ketamine looks safe and modestly opioid-sparing, but this trial was not powered to tell you whether that translates into anything a patient would notice. Alongside that, two papers on remimazolam. In the European Journal of Anaesthesiology, Takayama and colleagues pooled twelve randomised trials comparing remimazolam with sevoflurane for maintenance of general anaesthesia, a total of just under 740 patients [2]. Remimazolam cut the risk of intraoperative hypotension by roughly 60 percent, and trial sequential analysis supported that finding as reasonably stable. Mean arterial pressure and heart rate were higher with remimazolam, but only at scattered time points. The apparent reduction in postoperative nausea and vomiting is the part to treat cautiously — the authors themselves flag that this emerged in sensitivity analyses and was not robust in the primary analysis. And in Anaesthesia, Tang and colleagues addressed a practical question that follows directly: how do you dose remimazolam in patients living with obesity and obstructive sleep apnoea [4]? In forty-four volunteers, two thirds of whom had sleep apnoea, they built a population pharmacokinetic model for remimazolam and its metabolite. Total body weight drove clearance; sleep apnoea severity did not affect drug disposition at all. Even after a four-hour infusion in class two or three obesity, the context-sensitive half-time was about four minutes. Their practical recommendation is lean or ideal body weight for induction and adjusted body weight for maintenance, which reproduced the profile you'd get from total body weight dosing in a normal-weight patient.

Moving to analgesia and recovery, where three papers converge on the limits of opioid-sparing adjuncts. In Regional Anesthesia and Pain Medicine, Felippe and colleagues pooled ten randomised trials of perioperative intravenous lidocaine in adult spine surgery [4 correction — see reference list] — I'll restate that properly: this is the lidocaine meta-analysis [4a]. Let me give you the finding cleanly. Intravenous lidocaine reduced pain at 24 hours by about eight tenths of a point on a ten-point scale and cut opioid consumption by roughly 12 milligrams of morphine equivalents [4b]. The more interesting signal was procedure specificity: after instrumented fusion or complex spine surgery the reduction exceeded the one-point threshold usually considered clinically meaningful, whereas after simple decompression the effect was essentially nil. Heterogeneity was high, and baseline pain severity explained about half of it. Infusion rate made no difference. This was a post hoc subgroup analysis, so treat it as hypothesis-generating — but it does suggest that if you're going to run a lidocaine infusion, the patient having a multilevel fusion is a better candidate than the patient having a single-level decompression.

In the Journal of Clinical Anesthesia, Xiong and colleagues pooled 27 randomised trials, just over 3,000 patients, on perioperative vitamin C [5]. Vitamin C reduced 24-hour pain scores and cut morphine consumption by about four milligrams at 24 hours and nearly 12 milligrams at 48 hours, reduced the need for rescue analgesia by roughly a third, and lowered early postoperative nausea and vomiting. The most interesting finding was a roughly two-thirds reduction in complex regional pain syndrome type one in high-risk orthopaedic populations. But the reduction in chronic pain at three months was not statistically significant, and the authors are explicit that substantial heterogeneity and publication bias mean the current evidence does not support routine use. Set against those adjunct trials, a sobering picture of what actually happens to patients from the POPPY study in Anaesthesia [6]. Everson and colleagues followed nearly 7,900 United Kingdom day-case surgical patients through the first postoperative week. Pain scores fell over seven days, and yet about a quarter of patients still reported that pain was impairing function on day seven, and a third of patients had a poor pain outcome at some point in that first week. The factors associated with poor outcomes were largely non-surgical: treatment for anxiety or depression, pre-existing chronic pain, frailty, greater surgical magnitude, and head and neck procedures for pain, orthopaedic procedures for function. Older age was actually associated with a lower probability of poor pain outcomes, and opioid-naive patients did better on both counts. The message for the practising anaesthetist is that day-case does not mean recovered, and these are identifiable phenotypes you could target with enhanced preparation and follow-up before the patient ever reaches theatre.

That theme of preoperative phenotyping carries into two retrospective cohorts in Anesthesia and Analgesia, both in older adults. Lee and colleagues defined an autonomic vulnerability phenotype from the electronic health record — diabetes or hypertension, plus documented neuropathy, orthostatic hypotension, syncope, or unexplained bradycardia — and matched 612 pairs of patients over 65 having major noncardiac surgery with troponin surveillance [7]. Adjudicated myocardial injury occurred in about 14 percent of the vulnerable group versus about 9 percent of controls, roughly a 75 percent increase in the odds. Thirty-day major adverse cardiac events and one-year mortality were both higher. Crucially, intraoperative hypotension burden modified that relationship: in the highest hypotension quartile the excess risk was nearly tripled. This is retrospective and hypothesis-generating, but it points at a group in whom tight blood pressure control may matter more than average. The second paper, from Lee and Ahn, looked at body mass index and postoperative delirium in over 4,300 patients aged 65 and older [8]. Delirium occurred in about 15 percent overall. Overweight and class one obesity were associated with modestly lower delirium risk — but only in patients with a low comorbidity burden. In patients with a Charlson index of three or more, no body mass index category differed from normal weight. So the so-called obesity paradox for delirium is conditional; body mass index on its own is not a useful risk marker unless you read it alongside comorbidity.

Two final papers on airway management and organ protection. In the Canadian Journal of Anesthesia, Collins and colleagues reviewed nearly 5,300 general anaesthetics at an Australian tertiary-quaternary hospital [9]. Difficult airways occurred in about 4 percent of cases — consistent with published estimates — but 71 percent of those difficult airways were unanticipated, meaning roughly one in every 36 patients presented an airway difficulty that preoperative assessment did not predict. Reduced thyromental distance, restricted neck extension, and high Mallampati scores were significant predictors, but clearly insufficient. Videolaryngoscopy was used about four times more often when difficulty was anticipated, and where it was used it reduced poor glottic views by around 70 percent. The authors' conclusion is that because most difficulty is unanticipated, routine videolaryngoscopy is the rational default. And finally, in Anesthesia and Analgesia, Labanca and colleagues updated the meta-analysis of remote ischaemic preconditioning in noncardiac surgery — 79 randomised trials, over 9,300 patients [10]. The headline is negative: no significant reduction in all-cause mortality overall. A mortality benefit appeared only in the subgroup receiving preconditioning before induction of anaesthesia, and exploratory outcomes suggested less stroke, a shorter hospital stay by under a day, and lower peak renal injury biomarkers. These are subgroup and exploratory findings from mostly single-centre trials, so this remains a research question, not a practice change.

If you only have time for one paper this week, make it the Canadian Journal of Anesthesia difficult airway cohort [9]. It quantifies, in a contemporary population, how often airway difficulty arrives unannounced, and it gives you the clearest evidence-based argument yet for making videolaryngoscopy your first-line device rather than your rescue device.

Here are the key takeaways from this week in Anesthesiology. Most difficult airways are not predicted by preoperative assessment, which supports routine rather than selective videolaryngoscopy. Remimazolam produces less intraoperative hypotension than sevoflurane, and in patients living with obesity you should dose it by lean or ideal body weight for induction and adjusted body weight for maintenance, regardless of sleep apnoea severity. Low-dose ketamine modestly reduces opioid requirements in ventilated intensive care patients without improving delirium or ventilator-free days. Opioid-sparing adjuncts are procedure-specific: lidocaine helps most after instrumented fusion, and vitamin C is not yet ready for routine use. And in older adults, preoperative phenotypes matter — an autonomic vulnerability profile combined with a high intraoperative hypotension burden markedly raises myocardial injury risk, while body mass index only predicts delirium risk in those with low comorbidity burden. One more: a quarter of day-case patients still have pain limiting function a week after surgery.

That's your roundup for This Week in Anesthesiology. The full transcript and references are available on the episode page in your AudioScholar library. This is an AI-curated summary — for clinical decisions, always consult primary sources and current guidelines. See you next week.

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