Abstract
<title>Abstract</title> <p>Background Postoperative mechanically ventilated patients in surgical ICUs are at high risk of delayed extubation and ventilator-associated pneumonia (VAP). Traditional chest physiotherapy primarily facilitates airway secretion clearance; however, its immunomodulatory effects-particularly on the Th17/Treg-STAT3 inflammatory axis-have not yet been reported in human clinical trials. Methods This prospective, single-blind, randomized controlled trial enrolled 56 postoperative patients receiving invasive mechanical ventilation, who were randomly assigned to either a nurse-led comprehensive chest physiotherapy (CCPT) group (n = 29) or a routine care control group (n = 27). The stratified CCPT protocol integrated airway clearance techniques, respiratory muscle training, and progressive early mobilization. Peripheral blood Th17/Treg ratio, plasma IL-6, IL-17, and IL-10 levels, and nuclear STAT3 and Foxp3 expression were measured on day 2 (D2, intra-individual baseline) and day 4 (D4) post-intervention. Within-subject changes (Δ = D4 − D2) in immunological parameters were compared between groups using pooled linear regression following multiple imputation for missing data. Spearman‘s rank correlation was employed to examine the association between immune changes and mechanical ventilation duration. The trial was registered with the Chinese Clinical Trial Registry (ChiCTR2600118178). Results The CCPT group demonstrated a significantly greater reduction in STAT3 expression compared with the control group (mean difference = − 0.025; 95% CI: −0.032 to − 0.019; P = 0.028), along with a borderline trend toward decreased IL-6 levels (P = 0.060). No significant between-group differences were observed for ΔTh17, ΔTreg, ΔTh17/Treg, ΔIL-17, or ΔFoxp3 (all P > 0.05). The change in Th17/Treg ratio was positively correlated with mechanical ventilation duration (median Spearman’s rho = 0.268), indicating that a greater decline in Th17/Treg ratio was associated with shorter ventilation time. CCPT significantly reduced both mechanical ventilation duration (28.17 vs. 111.66 hours; P < 0.001) and ICU length of stay (69.70 vs. 136.67 hours; P < 0.001). VAP incidence tended to be lower in the CCPT group (3.4% vs. 22.2%; P = 0.063). Conclusions CCPT significantly suppresses STAT3 signaling in ICU patients undergoing mechanical ventilation after surgery and may promote the restoration of Th17/Treg immune balance, which is associated with improved clinical outcomes. These findings provide preliminary immunological evidence for incorporating CCPT into early ICU rehabilitation protocols.</p>