Impact of Frailty and Diaphragmatic Dysfunction on Outcomes in ARDS: Focusing on Perioperative Respiratory Management

The objective of this study is to assess the independent and combined impact of frailty (measured by the Clinical Frailty Scale, CFS) and diaphragmatic dysfunction (measured by diaphragm thickening fraction, DTF) on clinical outcomes in patients with acute respiratory distress syndrome (ARDS) and to discover if perioperative respiratory management strategies moderate these relationships.

A single-center retrospective cohort study of ARDS patients with radiographic severity classification who visited the ICU of Cangzhou Central Hospital between January 2020 and December 2023 was performed. Patients were divided in a frail group (CFS ≥ 4, n = 87) and nonfrail group (CFS < 4, n = 124). Within 24 h of ICU admission and on Days 3 and 7 of mechanical ventilation, bedside diaphragm ultrasound was performed; DTF and diaphragm excursion (DE) were measured. Outcome measures included mechanical ventilation parameters, perioperative respiratory management strategies, and clinical outcomes (28- and 90-day mortality, duration of mechanical ventilation, and ICU length of stay). Independent and interactive effects of frailty and diaphragmatic dysfunction on outcomes were evaluated using multivariable logistic regression, Cox proportional hazards models, and interaction analysis.

Frail patients were significantly older (71.3 vs. 58.4 years; p < 0.001) and had higher APACHE II and SOFA scores. Dynamic pulmonary function at rest was compared between the two groups; the frailty group demonstrated significantly lower DTF and higher proportions with diaphragmatic dysfunction (DTF < 20%: 16.2% ± 8.4% [vs. 28.7% ± 9.6%, p < 0.001] and DTF < 20%). Frail patients had significantly higher rates of 28-day mortality (44.8% vs. 23.4%, p = 0.002) and 90-day mortality (59.8% vs. 30.6%, p < 0.001). CFS ≥ 4 (OR = 2.84, 95% CI: 1.61-5.02) and DTF < 20% (OR = 3.16, 95% CI: 1.77-5.63) remained independently associated with mortality at Day 28 in multivariable analysis; the interaction term generated an even greater risk for mortality to occur (OR = 4.23, 95% CI: 2.37-7.54). In subgroup analysis, 28-day mortality was 55.6% for patients with frailty and concurrent diaphragmatic dysfunction. The combined predictive model including the CFS, DTF, and APACHE II scores was found to have an AUC of 0.851. In frail patients, mechanical ventilation duration was shorter in those who received inspiratory muscle training and early rehabilitation than in controls. In a 1:1 propensity score-matched sensitivity analysis (n = 148), both frailty (OR = 2.61, 95% CI: 1.42-4.79) and DTF < 20% (OR = 2.94, 95% CI: 1.58-5.47) were unchanging independent predictors; additive interaction was confirmed, RERI = 1.94, AP = 0.46, SI = 2.31. After IPTW adjustment, the IMT-treated frail patients had a 3.1-day (95% CI: 0.4-5.8, p = 0.024) reduction in mechanical ventilation duration with a nonsignificant trend toward lower 28-day mortality (p = 0.198).

Frailty and diaphragmatic dysfunction both have independent adverse effects on outcomes in ARDS, as well as a synergistic effect. However, systematic perioperative diaphragm ultrasound monitoring, personalized lung-protective ventilation strategies, and early inspiratory muscle rehabilitation have the potential to improve clinical outcomes in frail patients with concomitant disordered diaphragmatic function.