Harris, Benjamin R E

Body positioning exerts profound physiological effects in critically ill patients, influencing respiratory mechanics, ventilation-perfusion matching, hemodynamics, and overall clinical outcomes. Transitioning from an upright to a recumbent position alters thoracoabdominal pressure relationships, reduces ribcage contribution to tidal ventilation, and shifts ventilatory load to the diaphragm. These changes decrease functional residual capacity and promote airway closure in dependent lung regions, predisposing patients to atelectasis—an effect further amplified by intra-abdominal pathology or diaphragmatic weakness. Positioning also reshapes pulmonary perfusion and ventilation, which impact cardiopulmonary hemodynamics. These physiologic principles translate to important therapeutic applications across disease states. In ARDS, prone positioning improves oxygenation via a number of mechanisms, reduces ventilator-induced lung injury, and confers substantial mortality benefit. Prone position may also improve air flow distribution in COPD and enhance venous return in select cardiac physiologies. Conversely, conditions such as ascites, morbid obesity, and hepatopulmonary syndrome exemplify pathologic interactions between abdominal pressure, lung volumes, and posture, often requiring tailored positioning strategies to optimize respiratory performance. Overall, body positioning represents a potent, underutilized intervention in critical care. Understanding the mechanistic foundations of position-dependent changes in ventilation, perfusion, and pleural pressure can help clinicians strategically leverage positioning to improve patient outcomes across a spectrum of pulmonary and systemic illnesses.

Purpose Survivors of critical illness often acquire significant physical, cognitive, and psychological burdens following their intensive care unit (ICU) stay, termed “post-intensive care syndrome” (PICS). Screening for PICS is generally not performed outside of research settings largely due to lack of a simple assessment tool and time constraints. Methods This was a prospective cohort study at a single academic medical center in the USA. We included adults (18 years or older) who spent greater than 48 h in any ICU within the medical center. Following transfer out of the ICU and at 3 months, psychological, cognitive, and physical functioning were assessed using the Hospital Anxiety and Depression Scale, Impact of Event Scale-Revised, Montreal Cognitive Assessment-blind, and Barthel Index. We compared these validated questionnaires to a brief, 15-item PICS screening tool (5 questions/domain) that was developed by our multidisciplinary study team and administered to study participants after ICU discharge to general care. The primary objectives of this study were to assess the ability of validated screening tools administered at ICU discharge to predict PICS at 3 months and develop a novel screening tool for identifying patients at risk of PICS. Major Findings 191 participants completed the initial questionnaire, and 109 (56%) completed the 3-month follow-up. PICS tool scores were compared to 3-month follow-up data from validated questionnaires to evaluate predictive performance. Overall, the screening tool weakly-to-moderately correlated with continuous outcomes of the validated measures at 3-month follow-up. When evaluating sensitivity and specificity for individual domains, the screening tool had an area under curve of >0.7 for all three domains, indicating moderate-to-good sensitivity and specificity. Conclusions We developed a brief PICS screening tool that is feasible to use without prior training that modestly predicted the development of PICS following ICU stay.