Temporal Changes in Diagnostic Composition and Treatment Activity Among Mechanically Ventilated ICU Patients...

Background: Mechanically ventilated intensive care patients receiving hyperbaric oxygen therapy (HBOT) are uncommon and resource-intensive. We assessed temporal changes over 11 years in diagnostic composition, HBOT treatment activity, organ-support requirements, and in-hospital mortality at an academic centre. Methods: This single-centre retrospective cohort included mechanically ventilated ICU patients receiving HBOT during the period 2013-2023. Diagnoses were grouped as carbon monoxide (CO) poisoning, clostridial myonecrosis/gas gangrene, non-clostridial necrotising soft-tissue infections (NSTIs), or other indications. Annual patient and HBOT patient-session volumes and the annual number and proportion of nocturnal sessions were summarised descriptively. Calendar-time associations were estimated using exploratory univariable logistic regression with calendar year entered as a continuous predictor and are reported as odds ratios (ORs) per one-year increase with 95% confidence intervals (CIs). Results: Of 6410 HBOT-treated patients, 176 mechanically ventilated ICU patients (2.7%) underwent 1381 sessions; 781 (56.6%) were nocturnal. Annual volumes ranged from 10 to 22 patients and from 66 to 190 sessions, without a monotonic increase. The estimated OR per one-year increase was 0.85 (95% CI: 0.76-0.95) for CO poisoning, 0.85 (95% CI: 0.76-0.96) for clostridial myonecrosis/gas gangrene, 1.23 (95% CI: 1.11-1.36) for non-clostridial NSTIs, and 1.17 (95% CI: 1.04-1.31) for catecholamine infusion. Conclusions: Diagnostic composition shifted towards non-clostridial NSTIs. Catecholamine infusion was more frequent in the later calendar years, whereas the CVVHDF estimate was small and imprecise and the mortality estimate was near null. Persistent nocturnal activity supports ICU-capable infrastructure and flexible staffing for emergency HBOT.