Short-term effects of prone positioning on dyspnea and physiological Indicators in hospitalized, non-intubated adults with community-acquired pneumonia: a randomized controlled trial

Community-acquired pneumonia (CAP) may cause hypoxemia and dyspnea in hospitalized patients. Prone positioning may influence short-term respiratory outcomes, but evidence in hospitalized, non-intubated adults with CAP remains limited. This single-center, open-label, two-arm randomized controlled trial was conducted at Sina Farshchian Hospital, Hamadan, Iran, in 2025. Ninety-four eligible participants were randomly allocated in a 1:1 ratio using permuted blocks of four to prone or supine positioning. Participants in the prone group were positioned prone, whereas those in the control group remained supine, for 90 min. Dyspnea was the prespecified primary outcome and was assessed using a Visual Analog Scale (VAS) at baseline and 30, 60, and 90 min; no single post-intervention time point was prespecified as the sole primary time point. Secondary outcomes were respiratory rate, heart rate, systolic and diastolic blood pressure, and peripheral oxygen saturation (SpO₂). The primary analysis included 84 participants (42 per group) with available outcome data. Oxygen was administered throughout the intervention via a simple face mask or non-rebreather mask at a prescribed flow rate of 6–10 L/min. Dyspnea differed significantly between the prone and supine groups over the 90-minute observation period (time × group interaction, p < 0.001, η² = 0.520). At 90 min, mean dyspnea was 1.62 ± 0.94 in the prone group compared with 3.52 ± 1.87 in the supine group. Peripheral oxygen saturation (SpO₂) also differed significantly between groups over time (time × group interaction, p < 0.001, η² = 0.314), with mean values of 96.26 ± 2.81% in the prone group and 94.71 ± 2.90% in the supine group at 90 min. No statistically significant between-group differences were observed in heart rate, respiratory rate, systolic blood pressure, or diastolic blood pressure during the observation period. Ten participants discontinued the assigned intervention after randomization: five in the prone group because of positional intolerance and five in the supine group because of severe cough ( n = 2), non-adherence ( n = 2), or clinical deterioration ( n = 1). In this study population, prone positioning was associated with short-term between-group differences in dyspnea and peripheral oxygen saturation during the 90-minute observation period. No statistically significant between-group differences were observed in the measured hemodynamic parameters. These findings should be interpreted cautiously because of the short observation period and methodological limitations. Further studies are needed to evaluate the clinical relevance, longer-term outcomes, safety, tolerability, and feasibility of prone positioning in this population. Iranian Registry of Clinical Trials (IRCT), IRCT20120215009014N555. Registered on 18 April 2025. Available at https//www.irct.ir/trial/82,933.