Nutrition Support After Critical Illness

> Research explainer: This briefing examines verified primary research published 82 days before the briefing date. It is not a same-day research update and does not provide medical advice.

Research explainer

This briefing examines a post-ICU intervention that paired enhanced physiotherapy with optimised enteral nutrition for adults leaving intensive care with continuing rehabilitation and dietetic needs. The study’s central question was feasibility: whether the combined programme could be recruited to, retained, and delivered in hospital after ICU discharge. pmid:42326381

Evidence

PHOENIX was a mixed-methods, parallel-group, open-label randomised controlled feasibility trial across two UK university hospitals. It enrolled adult ICU survivors who had received four or more days of advanced respiratory support and had ongoing physiotherapy and dietetic rehabilitation needs at ICU discharge. Of 172 screened patients, 60 were eligible and all consented to participate. pmid:42326381

Participants were randomly allocated to an ICU-initiated enhanced physiotherapy and optimised nutrition intervention or usual care. Primary feasibility outcomes were recruitment rate, 30-day retention, and intervention fidelity. Secondary measures included days alive and out of hospital at 30 days, physical function, nutritional status, and quality of life; assessments occurred at baseline, at 14 days or hospital discharge if sooner, and at 30 and 90 days after randomisation. pmid:42326381

Retention at 30 days was 100%. Enhanced physiotherapy was delivered on 81% of available days, above the predefined feasibility threshold of 70%. Nutrition delivery met the stated progression criteria for calories, with 75.2% intake fidelity, and protein, with 83.7% intake fidelity. These are delivery findings, not estimates of whether the programme improved health outcomes. pmid:42326381

The reported preliminary physical comparisons included a higher proportion of intervention participants able to walk at least 30 m at hospital discharge than under usual care: 71.4% versus 37.9%, p = 0.009. The excerpt does not supply confidence intervals for this comparison, and the feasibility-study analysis was not designed for formal treatment-effect estimation or inferential comparisons. pmid:42326381

For 30-second sit-to-stand results, mean scores were 3.1 versus 1.7 at 14 days and 3.7 versus 2.4 at 30 days for intervention versus usual care. The supplied results also report a greater proportion demonstrating improvement in the intervention group compared with usual care, presented as 26.1% versus 59.3%, p = 0.019. Because the wording and direction in that sentence are internally difficult to reconcile, this briefing preserves the reported values and does not reinterpret them. pmid:42326381

Weight change during the intervention period was reported as mean ± SD −0.56 ± 4.73 kg in the intervention arm and −1.85 ± 6.31 kg with usual care. Overall weight loss at 30 days was reported as −3.02 ± 9.40 kg versus −2.62 ± 8.65 kg, respectively. These descriptive values should be read within the study’s stated feasibility purpose. pmid:42326381

Analysis — Feasibility and interpretation

The strongest evidence in this packet concerns operational feasibility, not clinical effectiveness. Recruitment targets were achieved within eight months, all eligible patients consented in the reported screening cohort, 30-day retention was complete, and the physiotherapy and nutrition-delivery metrics exceeded their stated feasibility benchmarks or progression criteria. Those findings support the narrower conclusion that the combined programme could be implemented and followed in the participating post-ICU hospital setting. They do not establish that the intervention improves mobility, nutritional recovery, quality of life, survival, days out of hospital, or cost-effectiveness compared with usual care. pmid:42326381

The reported between-group physical and weight observations are useful for planning a future trial, but they require restraint. The investigators describe the analysis as primarily descriptive and explicitly state that it was not designed to formally estimate treatment effects or support inferential comparisons. A p-value in a preliminary feasibility report does not by itself establish clinical importance, and the supplied material does not provide confidence intervals for every highlighted comparison. The programme combined two components, so the available evidence also cannot separate the contribution of enhanced physiotherapy from that of optimised enteral nutrition. pmid:42326381

Limitations

The study had a small sample size and only two sites; formal adjustment or subgroup analysis by site was not performed because it would be underpowered and could risk over-interpretation. The investigators report substantial overlap in confidence intervals for utility estimates, indicating considerable uncertainty around those estimates. The qualitative component on intervention and trial-methodology acceptability is to be reported separately, so it is not available in the supplied evidence for this briefing. pmid:42326381

The evidence therefore supports a future definitive multicentre randomised controlled trial to evaluate clinical and cost-effectiveness, as the authors state. It does not support patient-specific conclusions, treatment recommendations, or predictions about outcomes outside the trial population and settings. pmid:42326381