ICU physiotherapy under the microscope: can we measure its true cost?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Adults aged 18 years or older. * Admission to the intensive care unit. * Invasive mechanical ventilation via endotracheal tube or tracheostomy. * Ability to remain in the supine position during the measurement period. * Clinical indication for supine physiotherapy as part of usual ICU care. * Richmond Agitation-Sedation Scale (RASS) score between -5 and 0 at the time of the session. * Hemodynamic stability, defined as mean arterial pressure ≥65 mmHg with or without vasopressor support and no initiation or increase \>20% in vasopressor dose within the previous 60 minutes. * Respiratory stability, defined as no changes in ventilator settings within the previous 30 minutes and oxygen saturation ≥90% with FiO₂ ≤0.60 and PEEP ≤12 cmH₂O. * Technical conditions allowing valid indirect calorimetry measurement (absence of significant air leaks and no planned circuit disconnections). Exclusion Criteria: * Use of extracorporeal membrane oxygenation (ECMO) or other extracorporeal gas exchange systems. * Continuous renal replacement therapy during the measurement period when it may interfere with metabolic measurements. * Significant air leaks in the airway or ventilator circuit that invalidate indirect calorimetry measurements. * Planned procedures or interventions during the measurement period that could interfere with gas exchange (e.g., bronchoscopy, recruitment maneuvers, ventilator setting changes). * Severe respiratory instability requiring FiO₂ \>0.60 or PEEP \>12 cmH₂O. * Ongoing neuromuscular blockade infusion. * Clinical contraindications to limb mobilization (e.g., unstable fractures, active bleeding, uncontrolled intracranial hypertension). * Agitation or risk of unplanned device removal (RASS \>0). * Refusal of participation by the patient or legally authorized representative, when applicable.