The authors used a structured descriptive approach rather than a formal guideline process. For each recommendation, they identified the predominant study design, judged the consistency of findings across available studies, summarised residual uncertainties, and assigned a descriptive evidence-strength label of high, moderate, low, or insufficient. This transparency is important, because the headline conclusion is sobering: the evidence underpinning many widely practised rehabilitation strategies remains limited and heterogeneous, preventing firm recommendations and leaving clinicians to navigate a field where well-established physiological reasoning is not always matched by rigorous trial data.

Underpinning the syndrome is a cascade of biological injury that begins in the acute phase. The strongest evidence points to early neuromuscular damage and rapid skeletal-muscle wasting during critical illness. ICU-acquired weakness, the hallmark of physical PICS, reflects a combination of critical illness myopathy, polyneuropathy, and disuse atrophy, driven by enhanced proteolysis through the ubiquitin-proteasome and autophagy pathways, suppressed protein synthesis, oxidative stress, mitochondrial dysfunction, and impaired excitation-contraction coupling. Beyond the loss of muscle mass, persistent alterations in muscle metabolism, mitochondrial bioenergetics, and gene expression have been documented in survivors, and emerging work implicates epigenetic changes such as altered DNA methylation detectable years after ICU admission.

The brain is similarly vulnerable. Systemic inflammation can compromise the blood-brain barrier, allowing peripheral mediators to trigger central neuroinflammation. Activated microglia and disrupted neuronal networks contribute to cognitive dysfunction and mood disturbance, while hypoxaemia, impaired cerebral autoregulation, and microvascular injury exacerbate neuronal vulnerability. Structural imaging frequently reveals white-matter abnormalities associated with long-term cognitive deficits, and critical illness episodes have been linked to accelerated cognitive decline resembling that seen after moderate traumatic brain injury. Neuroendocrine disruption affecting the hypothalamic-pituitary-adrenal, thyroid, and gonadal axes may contribute to catabolism, metabolic dysregulation, and impaired recovery, persisting in some patients for five years or more. Frailty occupies a bidirectional position, serving both as a risk factor for critical illness and as a consequence of it, further complicating attribution of long-term impairments.

Defining the syndrome itself remains contested. The 2012 consensus definition requires impairment in at least one of the three core domains, and the authors argue against tightening this threshold, noting that multidomain impairment is relatively uncommon, affecting roughly a quarter of survivors at three months and about 21 percent at twelve months, while single-domain impairment still carries substantial functional cost. PICS overlaps with post-sepsis syndrome, chronic critical illness, post-COVID conditions, and myalgic encephalomyelitis/chronic fatigue syndrome, and attribution is further complicated by pre-existing cognitive impairment, psychiatric illness, and physical disability. Because no dedicated International Classification of Diseases code exists for PICS, coding, reimbursement, and sustainable staffing remain barriers, although a national code has recently been approved in Germany.

On assessment, the review recommends a pragmatic two-step pathway based on expert consensus rather than validated diagnostic criteria. Brief screening tools, including the PHQ-4 for mental health, the Mini-Cog for cognition, and the Timed Up-and-Go for physical function, are applied to all survivors, with comprehensive multidisciplinary evaluation reserved for those who screen positive, ideally around three months after hospital discharge and with reassessment at six and twelve months. Additional clinically relevant domains, including fatigue affecting more than half of survivors in the first year, post-extubation dysphagia, persistent pain reported by roughly a third to a half of survivors, sleep disturbance, and health-related quality of life, are inconsistently captured. Return to work integrates all three core domains and is starkly affected: roughly two-thirds of previously employed survivors remain jobless at three months, and about 40 percent at twelve months.

Prevention starts in the ICU with the ABCDEF bundle, which combines pain assessment, spontaneous awakening and breathing trials, light sedation, delirium prevention, early mobilisation, and family engagement. Higher bundle performance is consistently associated with less delirium, shorter mechanical ventilation, reduced length of stay, and a higher likelihood of discharge home, although effects on mortality are inconsistent and long-term functional outcomes remain insufficiently studied. Early mobilisation, defined as mobilisation within 72 hours of ICU admission including passive and active components, shows short-term benefits in trials and meta-analyses, but long-term evidence is conflicting and appears to depend on dose and comparator. No trial has directly compared mobilisation doses, a gap identified as the highest research priority and now being addressed by the ESICM’s first international study, ERUPT. Adverse-event rates are below three percent and typically transient, with safety demonstrated even during extracorporeal membrane oxygenation, renal replacement therapy, and vasopressor support.

The transition from ICU to the general ward represents a high-risk window. In a UK survey of 25 centres, 98 percent of patients required ongoing physiotherapy and 70 percent were at risk of malnutrition, yet ward-based rehabilitation is frequently fragmented by competing priorities, lower staffing ratios, and poor handovers, creating a so-called post-ICU gap that may erode gains achieved in intensive care. Structured multidisciplinary continuity of care, explicit rehabilitation goals, and standardised handovers covering mobilisation, nutrition, and outstanding risks are therefore emphasised. After hospital discharge, individualised multimodal rehabilitation across inpatient, outpatient, community, and home-based models is supported, and meta-analyses show fairly consistent improvement in aerobic capacity, rated high-certainty in one synthesis of fourteen randomised trials, but effects on quality of life are inconsistent. Three components remain chronically under-delivered: structured pharmacist-led medication review of psychoactive drugs carried forward from the ICU, explicit treatment rather than mere measurement of pain, fatigue, sleep disturbance, and dysphagia, and vocational rehabilitation to support return to work.

The organisation of post-ICU recovery services varies dramatically across health systems, from well-integrated national follow-up programmes in parts of Europe to very limited provision elsewhere. A cautionary finding emerges from a 2024 randomised trial in which a hospital-based, intensivist-led multidisciplinary consultation model produced worse one-year outcomes than standard follow-up, possibly because the intervention was largely diagnostic and referral-based, with treatment changes in fewer than eight percent of patients and modest attendance. The authors argue this does not undermine survivorship care itself, but rather exposes the danger of assuming that a single clinic-centred model suits every survivor. Emerging approaches, including telehealth, virtual reality, and peer-support programmes, aim to widen access, though evidence remains preliminary and digital barriers persist for frail or remote patients.

On the family dimension, the review reframes PICS-family through a systems perspective in which critical illness affects the family as an interdependent biopsychosocial unit, shaping and being shaped by the patient’s recovery trajectory. Nurse-led, multicomponent family interventions delivered during and after the ICU stay appear promising for improving communication, shared decision-making, and early psychological outcomes, whereas ICU diaries have not shown consistent benefit. The review closes with a research agenda: harmonised diagnostic criteria, longitudinal phenotyping of recovery trajectories, determination of the optimal dose and timing of rehabilitation, rigorous head-to-head comparison of follow-up models, mechanistic studies incorporating biomarkers and epigenetics, fair and transparent use of artificial intelligence for risk prediction, culturally and spiritually responsive care, and a universal ICD code. Until that agenda is fulfilled, the authors conclude, post-intensive care syndrome should be understood not as a static post-discharge diagnosis but as a dynamic recovery process spanning the entire continuum from intensive care admission to long-term survivorship.

Subject of Research: Post-intensive care syndrome and rehabilitation across the ICU recovery continuum

Article Title: Rehabilitation and the post-intensive care syndrome across the recovery continuum: a narrative review

Article References: Rehabilitation and the post-intensive care syndrome across the recovery continuum: a narrative review. (n.d.). https://doi.org/10.1007/s00134-026-08600-5

Image Credits: AI Generated

DOI: 10.1007/s00134-026-08600-5

Keywords: post-intensive care syndrome, critical illness recovery, ICU-acquired weakness, rehabilitation, ABCDEF bundle, early mobilisation, cognitive impairment, PICS-family, ICU follow-up, neuroinflammation, skeletal muscle wasting, survivorship care