This week in Anesthesiology

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Welcome to This Week in Anesthesiology. This week we're covering 10 notable papers spanning the prevention of acute and chronic postsurgical pain, anaesthetic choices and the postoperative brain, and perioperative safety systems from fluids to blood to allergy labels. Let's dive in.

We begin with chronic postsurgical pain, the outcome that keeps resurfacing as one of the most stubborn problems in our specialty. In the British Journal of Anaesthesia, Wang and colleagues report a multicentre, double-blind trial of 914 adults having video-assisted thoracoscopic lung resection, randomised to low-dose esketamine or saline [1]. The regimen was a 0.1 milligram per kilogram bolus at induction, an intraoperative infusion of 0.1 milligrams per kilogram per hour, and a postoperative infusion of 0.015 milligrams per kilogram per hour for 48 hours. Among the 873 patients analysed, chronic pain at three months fell from about 21 percent to about 15 percent, a reduction in the odds of roughly forty percent. Pain scores and rescue analgesic use in the first 48 hours were also lower, and the authors report no increase in adverse effects. One caveat is that the primary definition counted any pain score of one or more on coughing, a sensitive threshold, although a post hoc analysis using a more clinically meaningful threshold of three pointed the same way. The trial was conducted in China and in a single procedure, so generalisability to other operations and populations remains to be shown, but this is a large, well-powered positive trial for a cheap intervention. That result fits neatly with a translational review in Pain by Pogatzki-Zahn and colleagues [2], who argue that chronic postsurgical pain emerges dynamically across the pre-, intra- and postoperative phases through interacting biological, psychological and surgical factors. They note that current risk tools are not yet precise or generalisable enough, and they propose integrating biological signatures with psychosocial factors into prognostic models that could eventually target mechanism-based prevention at the patients most likely to benefit. Read together, the esketamine trial offers a candidate intervention, and the review frames the open question of who should receive it.

Regional anaesthesia had a busy week, with one clear head-to-head result and two papers that temper enthusiasm. In the Journal of Clinical Anesthesia, Keklicek and colleagues randomised 90 adults having septorhinoplasty to bilateral ultrasound-guided infraorbital nerve block or transnasal sphenopalatine ganglion block, each with 2 millilitres of 0.5 percent bupivacaine per side [3]. Quality of recovery scores at 24 hours were about twelve points higher with the infraorbital block, comfortably above the prespecified minimal clinically important difference of eight. Rescue analgesia was needed in roughly one in nine infraorbital patients compared with about half of the sphenopalatine patients. It is a single-centre trial in healthy adults, and the authors themselves call the secondary findings hypothesis-generating, but the primary result is large and patient-centred. Contrast that with a Bayesian meta-analysis in the British Journal of Anaesthesia from Azem and colleagues on kidney transplant recipients [4]. Across 14 trials and about 900 participants, quadratus lumborum and transversus abdominis plane blocks both lowered pain scores, but neither block had a high probability of exceeding the one-point threshold that patients would actually notice. Opioid use at 24 hours fell by roughly 15 morphine milligram equivalents with the quadratus lumborum block and about 10 with the plane block, reductions very likely to be clinically meaningful. No block was preferred over the other, graft function and safety data were too sparse to pool, twelve registered trials remain unpublished, and certainty was rated very low. Finally, a systematic review of preclinical studies in the Journal of Clinical Anesthesia by De Cassai and colleagues asks whether injection pressure monitoring can detect hazardous needle placement [5]. Across 28 animal and cadaver studies, intraneural injection generally produced higher pressures, but overlap between needle positions was substantial, low pressure did not reliably exclude intraneural injection, and the widely cited 15 psi threshold performed inconsistently. The authors conclude that pressure monitoring may give a nonspecific warning of a poorly compliant structure, but no universal threshold can be defined and preclinical data cannot show whether it reduces nerve injury.

Our third theme is the postoperative brain, and two papers address delirium from different angles. In the British Journal of Anaesthesia, Kim and colleagues ran a single-centre, double-blind noninferiority trial in 686 patients having elective neurovascular surgery such as aneurysm clipping or microvascular decompression, comparing remimazolam-based total intravenous anaesthesia with flumazenil reversal against propofol-based anaesthesia [6]. Delirium within five days occurred in about 13 percent of the remimazolam group and about 11 percent of the propofol group, which met the prespecified ten-point noninferiority margin. Remimazolam patients had essentially no hypotension below a mean pressure of 65, and more were extubated in the operating room, about 85 percent compared with about two thirds. The authors flag an important caveat: delirium was far less common than anticipated, which makes a ten-point margin generous relative to the baseline rate, so the trial lessens but does not eliminate the benzodiazepine delirium concern. Alongside it, a large meta-analysis in the Journal of Clinical Anesthesia from Hormis and colleagues pooled 87 randomised trials with more than 30,000 patients comparing processed EEG guidance with no processed EEG [7]. Guided anaesthesia reduced propofol and volatile use and cut the risk of postoperative delirium by about a quarter, with modest gains of a few minutes in extubation time, orientation and recovery unit stay. Evidence was strongest for the bispectral index, estimates for other devices were less precise, and heterogeneity was substantial. There is a tension worth noting here, since some large individual trials of EEG guidance have been neutral for delirium, and pooling across 87 heterogeneous studies cannot fully resolve that; the meta-analysis strengthens the case for processed EEG but is not the final word.

Our final theme gathers three papers on perioperative safety systems, each probing whether a routine practice is doing what we assume. In the British Journal of Anaesthesia, Klompmaker and colleagues performed daily lung ultrasound and venous excess ultrasound grading in 200 patients undergoing major gastrointestinal surgery [8]. Signs of reduced fluid tolerance appeared in just over a third of patients, almost entirely driven by pulmonary congestion rather than systemic venous congestion, and in most affected patients the finding lasted only a day. Reduced fluid tolerance was associated with roughly triple the odds of a hospital stay beyond a week, but not with major complications, and many patients declined repeated scans because of the burden. This is a single-centre observational study, so it describes epidemiology rather than showing that ultrasound-guided fluid management improves outcomes. On the blood side, Aranbitski and colleagues in the Journal of Clinical Anesthesia examined cell salvage volume in cardiac surgery [9]. In 677 patients with routine coagulation tests, salvage volume was not associated with any change at the volumes typically reinfused. In a much smaller exploratory cohort of 50 patients with viscoelastic testing and higher salvage volumes, more salvaged blood was associated with weaker functional fibrinogen clot strength. Being retrospective and small, it is hypothesis-generating, but the authors suggest viscoelastic monitoring may be most informative when large salvage volumes are expected. Lastly, a commentary in the British Journal of Anaesthesia by Webster argues that perioperative allergy labels appear to be harming rather than helping patients [10]. Labelled patients seem to have more complications, paradoxically including more allergic reactions, while roughly 90 percent of labels prove incorrect on formal testing. Webster frames this as a systems design failure and a research opportunity, an argument rather than new trial data, but one that resonates with ongoing delabelling efforts.

If you only have time for one paper this week, make it the esketamine trial from Wang and colleagues in the British Journal of Anaesthesia [1]. Chronic postsurgical pain has resisted most pharmacological prevention attempts, and a large multicentre double-blind trial showing a meaningful reduction with an inexpensive, widely available drug reopens the question of whether low-dose ketamine-class infusions belong in preventive strategies for high-risk operations.

Here is what this week's evidence adds up to in Anesthesiology. First, perioperative low-dose esketamine reduced three-month chronic pain after thoracoscopic lung resection in one large trial, though replication in other procedures and settings, and clarity on which patients benefit most, are still needed. Second, regional techniques show uneven evidence: infraorbital block clearly outperformed sphenopalatine block for recovery after septorhinoplasty in a single trial, while blocks after kidney transplant reliably reduce opioids but with very low certainty and unknown graft effects, and injection pressure thresholds lack validation. Third, remimazolam with flumazenil reversal was noninferior to propofol for delirium after neurovascular surgery with less hypotension, but a lower than expected delirium rate softens that conclusion. Fourth, pooled trials associate processed EEG guidance with roughly a quarter less delirium and slightly faster recovery, strongest for the bispectral index, though heterogeneity remains. Fifth, observational work suggests postoperative pulmonary congestion is common and transient, high-volume cell salvage may weaken fibrinogen function, and inaccurate allergy labels may cause harm, all questions awaiting interventional studies.

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

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