This Week in Critical Care — Aug 5, 2026

Welcome to This Week in Critical Care. This week we're covering eight notable papers spanning the kidney in critical illness, the search for treatable sepsis phenotypes, and how we dose and interpret our anti-inflammatory therapies. Let's dive in.

We start with the kidney, which dominates this week's pool. In Critical Care Medicine, Fage and colleagues asked whether renal Doppler could tell us which septic shock patient needs a higher blood pressure target [1]. Eighty patients in early septic shock underwent a standardised two-hour mean arterial pressure test, stepping from sixty-five to seventy up to eighty to eighty-five millimetres of mercury, with renal resistive index measured at each stage. Twenty-nine percent were classed as responders, meaning their resistive index fell meaningfully. They were then randomised to a low or high pressure target for five days, stratified by that response. The result runs against the hypothesis: among resistive index responders, the higher target did not improve diuresis, Kidney Disease Improving Global Outcomes stage, need for renal replacement therapy, or creatinine. If anything, the non-responders had higher urine output on the high target, an exploratory finding the authors are careful not to oversell. The practical message is that a falling resistive index during a pressure challenge does not identify patients who will benefit from chasing a higher mean arterial pressure, so this test is not ready to individualise your vasopressor targets at the bedside.

Staying with the kidney but moving to prediction and reporting, Critical Care Medicine also published a secondary analysis of the German SISPCT trial looking at H3.1 nucleosomes, a marker of neutrophil extracellular trap release [7]. In just under a thousand septic patients, admission levels were roughly twice as high in septic shock as in sepsis. After adjustment, each tenfold rise in nucleosome level was associated with about a fifty percent increase in twenty-eight-day mortality, and with an eighty percent increase in the risk of needing renal replacement therapy by day twenty-eight, even after controlling for lactate, procalcitonin and C-reactive protein. That is a biologically coherent signal linking excessive NETosis to organ failure. But before anyone orders a new assay, read the companion piece in Intensive Care Medicine [5]. Yu and colleagues systematically reviewed one hundred and twenty-two diagnostic accuracy studies of acute kidney injury biomarkers and found the literature essentially unusable: fifteen were too poorly reported to assess, only nineteen addressed diagnosis within forty-eight hours of sampling, and only sixteen were high quality by QUADAS-2. Compliance with existing reporting standards was so low that meta-analysis was impossible. A seventeen-member international panel has now produced STARDaki, a consensus extension covering patient selection, reference standards and test-retest reliability. Taken together, these two papers say that promising kidney biomarkers keep arriving, and the field still cannot pool them.

The kidney theme closes with a large observational study in Shock on burn-associated shock [8]. Using the TriNetX global network, the investigators identified over six hundred thousand adult burn patients, of whom about one in fifteen developed shock within seven days, and propensity-matched more than thirty-six thousand pairs. Shock roughly doubled three-month mortality and increased acute kidney injury by about two-thirds, but the striking figure is renal replacement therapy, which was more than four times as likely at three months and still more than three times as likely at one year. Absolute rates were low, and these are administrative coding data, so ascertainment is imperfect. Still, the persistence of the renal signal out to a year argues for structured kidney follow-up in burn patients who were shocked, not just discharge and forget.

Our second theme is phenotyping, and whether it can move from description to treatment selection. The American Journal of Respiratory and Critical Care Medicine published a translational study by Taenaka and colleagues that does something most phenotyping work has not [4]. Latent class analysis in five hundred and forty-eight ICU patients with pulmonary sepsis recovered the familiar hyperinflammatory and hypoinflammatory classes, with the hyperinflammatory group showing more lung injury and higher mortality. The novel step was building a mouse pneumococcal pneumonia model in which, despite identical pathogen exposure and identical baseline conditions, latent class analysis again separated two groups with divergent injury and survival trajectories. Crucially, dexamethasone and interleukin-6 receptor blockade benefited only the more inflamed animals. That is a mechanistic argument for why unselected anti-inflammatory trials keep coming out neutral, and it gives us a preclinical platform for testing phenotype-targeted drugs before they reach patients. In Shock, a complementary approach from the Korean Sepsis Alliance registry applied k-means clustering to nine routine emergency department variables, including vital signs, mental status, lactate and the Clinical Frailty Scale [6]. Six phenotypes emerged in nearly ninety-five hundred patients and reproduced in an independent later cohort, with seven-day mortality ranging from under seven percent to nearly thirty-two percent. Be careful how you read this, though: the extreme-severity clusters were bootstrap-robust while the intermediate ones were not, and the authors themselves conclude these are cross-sectional signatures along a continuous severity spectrum rather than true subtypes. The most useful insight is their decomposition of bundle non-compliance: missing a one-hour vasopressor target can mean the criterion was never met, which is appropriate withholding, or that treatment was delivered late. Those are opposite quality problems, and severity scores cannot tell them apart.

The final theme is drug dosing and safety, where two papers in the Journal of Critical Care push in different directions. Boyd and colleagues report a Dutch nationwide prospective cohort of eight hundred and forty-eight patients with COVID-19 acute respiratory distress syndrome across twenty-two centres [3]. Using marginal structural models with inverse probability weighting to emulate a per-protocol analysis and handle time-varying confounding, high-dose corticosteroids, meaning more than six milligrams of dexamethasone equivalent, were associated with roughly two and a half times the hazard of death over twenty-eight days compared with standard dosing. The risk was concentrated in men and in those who started high-dose therapy late, at a median of nine days after ICU admission. Confounding by indication is the obvious concern even with sophisticated weighting, since late escalation usually signals a deteriorating patient, but the direction is consistent enough to caution against reflexive dose escalation. On the safety side, Zampieri and colleagues performed a post-hoc analysis of two hundred and twelve DEFENDER trial patients who had acute kidney injury at enrolment [2]. Dapagliflozin showed no excess mortality, no excess kidney replacement therapy, and no divergence in creatinine, urine output, fluid balance or acid-base trajectories over the first five days. Confidence intervals were wide and the authors are explicit that neither moderate harm nor moderate benefit can be excluded, so this is a green light for a dedicated trial, not for routine use.

If you only have time for one paper this week, make it the Critical Care Medicine renal resistive index study [1]. It is a randomised physiological trial that closes off a plausible and increasingly popular route to individualising blood pressure targets, and negative findings like this one save us from adopting a bedside test that does not work.

Here are the key takeaways from this week in Critical Care. First, renal Doppler responsiveness during a mean arterial pressure challenge does not identify septic shock patients who will benefit from a higher pressure target. Second, admission H3.1 nucleosome levels track mortality and dialysis risk in sepsis, but the wider acute kidney injury biomarker literature is too poorly reported to pool, and the new STARDaki standard is an attempt to fix that. Third, burn patients who develop shock carry a several-fold higher risk of needing renal replacement therapy out to a year, so plan renal follow-up. Fourth, inflammatory phenotypes in pneumonia now have a mouse model in which only the inflamed animals respond to steroids or interleukin-6 blockade, supporting enrichment strategies in future trials. And fifth, high-dose corticosteroids in COVID-19 acute respiratory distress syndrome were associated with substantially higher mortality, while starting dapagliflozin in critically ill patients with acute kidney injury looked safe but unproven.

That's your roundup for This Week in Critical Care. 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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