A recent Intensive Care digest,
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Study Type: Secondary analysis of randomized controlled trial data

Key Question: What bedside factors determine tidal recruitment/derecruitment in spontaneously breathing ARDS patients receiving pressure support ventilation?

Key Findings:

• Tidal recruitment/derecruitment was significantly lower with EIT-guided PEEP versus table-guided PEEP (11.3% vs 21.9%, P=0.008)
• Three independent determinants of higher tidal recruitment/derecruitment: more negative end-expiratory transpulmonary pressure, greater lung collapse, and non-focal infiltrate pattern
• Higher respiratory drive and effort correlated with increased tidal recruitment/derecruitment

Clinical Relevance: This provides practical EIT-based guidance for UK intensive care clinicians to identify and potentially reduce harmful tidal recruitment/derecruitment in spontaneously breathing ARDS patients through optimized PEEP selection.

Limitations: Secondary analysis of a small dataset (29 patients) limits generalizability of findings.

Study Type: Retrospective multicenter cohort study

Key Question: What are the clinically meaningful thresholds for one-year change in quantitative CT-derived fibrosis scores in idiopathic pulmonary fibrosis patients?

Key Findings:

• Minimal clinically important differences were 2.72% for FVC-anchored and 4.52% for DLco-anchored changes in fibrosis score
• Prognostic threshold of ≥4.05% increase in fibrosis score was independently associated with worse transplant-free survival (adjusted HR 2.78, 95% CI 1.36-5.68)
• These thresholds were validated in an external cohort and remained predictive of both overall and 3-year transplant-free survival

Clinical Relevance: Provides evidence-based CT monitoring thresholds for IPF patients that could standardise disease progression assessment and inform transplant referral decisions in UK respiratory services.

Limitations: Retrospective design limits causal inference and generalisability may be affected by algorithm-specific variations in fibrosis quantification methods.

Study Type: Expert consensus statement/research prioritization framework

Key Question: What are the evidence gaps and research priorities for improving the US Air Quality Index as a tool to protect respiratory health?

Key Findings:

• Systematic literature review revealed significant knowledge gaps: limited evidence on AQI effectiveness in changing patient behaviour, few studies on health outcomes from AQI use, and minimal research on patient interpretation of AQI messaging
• Expert committee identified five priority research domains: AQI structure, sub-daily exposure estimation, communication strategies, clinical implementation, and health outcome evaluation
• Specific recommendations include developing multi-pollutant exposure indices, assessing patient understanding of AQI warnings, and measuring whether AQI-guided behaviours actually reduce exposure and improve outcomes

Clinical Relevance: UK clinicians managing respiratory patients may benefit from this framework when considering how to communicate air quality risks, particularly relevant given increasing focus on environmental health factors in NHS care pathways.

Limitations: This represents expert opinion and research prioritisation rather than new clinical evidence.

Study Type: Nationwide population-based matched cohort study

Key Question: What is the long-term cardiovascular risk in ICU survivors of severe COVID-19 compared to matched controls?

Key Findings:

• ICU survivors of severe COVID-19 (n=3,350) had 42% increased risk of atherosclerotic cardiovascular disease compared to controls (sHR 1.42, 95% CI 1.26-1.60)
• Risk of hospitalisation for atrial fibrillation increased by 85% (sHR 1.85, 95% CI 1.64-2.10) and heart failure by 81% (sHR 1.81, 95% CI 1.57-2.09)
• All-cause mortality was 48% higher in COVID-19 survivors (HR 1.48, 95% CI 1.26-1.74) over three years

Clinical Relevance: UK critical care clinicians should consider enhanced cardiovascular surveillance and risk factor modification in COVID-19 ICU survivors, potentially informing post-discharge follow-up protocols and resource planning.

Limitations: Swedish population data may not be generalisable to UK demographics and healthcare systems.

Study Type: Prospective multicenter cohort study (ancillary analysis)

Key Question: Does negative-pressure ICU room isolation reduce the risk of COVID-19-associated pulmonary aspergillosis compared to neutral-pressure rooms?

Key Findings:

• Probable invasive pulmonary aspergillosis occurred in 2.0% of patients in negative-pressure rooms versus 4.8% in neutral-pressure rooms (adjusted HR 0.44, 95% CI 0.21-0.90, p=0.024)
• No significant difference found for putative aspergillosis or Aspergillus colonisation between room types
• Probable aspergillosis was associated with longer mechanical ventilation duration and ICU stay

Clinical Relevance: This suggests negative-pressure isolation may provide additional protection against invasive aspergillosis in mechanically ventilated COVID-19 patients, potentially informing ICU design and patient allocation decisions in UK critical care units.

Limitations: Small event rates and potential unmeasured confounders limit the robustness of findings, requiring validation in future studies.

Study Type: Prospective observational cohort study with machine learning analysis and external validation

Key Question: How do plasma biomarkers, individually and combined using machine learning, compare to traditional severity scores for predicting 90-day mortality and kidney outcomes in critically ill patients?

Key Findings:

• Machine learning models using 15 biomarkers achieved AUC 0.74 for 90-day mortality prediction, significantly outperforming severity scores (AUC 0.64, p<0.001)
• sTREM-1 alone demonstrated comparable performance (AUC 0.72) to complex multiparametric models and was consistently the strongest individual predictor
• Results were validated externally in sepsis patients and replicated for major adverse kidney events prediction

Clinical Relevance: sTREM-1 could provide UK intensive care clinicians with a single, practical biomarker for risk stratification that outperforms current severity scoring systems while avoiding the complexity of multi-biomarker panels.

Limitations: Post-hoc analysis design limits the strength of conclusions compared to prospectively designed biomarker studies.

Study Type: Prospective observational multicentre study

Key Question: How does energy expenditure change over time in patients with persistent critical illness (ICU stay ≥10 days)?

Key Findings:

• Energy expenditure follows a biphasic pattern, increasing to peak around day 10, then declining (p<0.001), with inflection point coinciding with onset of persistent critical illness
• Three distinct metabolic trajectories identified: hypo-, normo-, and hypermetabolism (entropy 0.63)
• Urea:creatinine ratio increased significantly over first 10 days (p<0.001), indicating enhanced protein catabolism

Clinical Relevance: These findings may inform nutrition strategies for long-stay ICU patients in the NHS, suggesting energy requirements change predictably during prolonged critical illness and supporting individualised metabolic approaches.

Limitations: Latent class analysis showed modest entropy (0.63), indicating potential overlap between metabolic subgroups and limiting clinical applicability of the three-trajectory model.

Study Type: Randomized controlled pilot trial

Key Question: Is early isoflurane sedation safe and effective compared to propofol in neurocritical care patients with invasive ICP monitoring but without intracranial hypertension?

Key Findings:

• Both isoflurane and propofol achieved 100% sedation efficacy (measured by RASS and BIS) in 30 patients over 72 hours
• No serious adverse drug reactions occurred in either group, with stable ICP and cerebral perfusion pressure throughout
• Isoflurane did not require increased vasopressor support compared to propofol

Clinical Relevance: This suggests inhaled anaesthetic sedation may be a viable alternative to propofol in selected neurocritical care patients, potentially offering benefits such as reduced propofol infusion syndrome risk and easier titration.

Limitations: Very small sample size (n=30) limits generalisability and power to detect clinically important differences between groups.