Negative inspiratory force predicts extubation failure after planned extubation in a medical ICU: a prospective cohort study.

OBJECTIVES: Although negative inspiratory force (NIF) has been studied in relation to weaning failure, evidence addressing extubation failure after a successful spontaneous breathing trial (SBT) remains limited. In standardized, protocol-based weaning programs, ventilator-measured NIF may offer information for extubation decisions, but prospective data are scarce. METHODS: We performed a prospective observational cohort study in medical ICUs using a respiratory care practitioner-driven, standardized weaning program. Adult patients receiving invasive mechanical ventilation for ≥2 calendar days were enrolled between November 2017 and February 2022. Planned extubation episodes after a successful SBT were analyzed. NIF was measured at the bedside by respiratory care practitioners using the ventilator's built-in function and categorized a priori. The primary outcome was extubation failure, defined as reintubation within 48 h after extubation. RESULTS: Among 622 planned extubation episodes, extubation failure occurred in 97 (15.6%). Extubation failure rates decreased stepwise across increasing NIF categories (35.7% for NIF <15 cmH₂O vs. 11.2% for NIF ≥25 cmH₂O; P for trend <0.001). In the fully adjusted model, compared with NIF <15 cmH₂O, NIF 20-24 cmH₂O and ≥25 cmH₂O were independently associated with lower odds of extubation failure (adjusted odds ratios of 0.29 and 0.25, respectively). Hypercapnic or hypoxemic respiratory failure, deep sedation, thick secretions, higher non-neurologic Sequential Organ Failure Assessment score, and delirium were also independently associated with extubation failure. Extubation failure was associated with a higher rate of tracheostomy before ICU discharge (66.0% vs. 5.0%) and higher ICU mortality (10.3% vs. 3.2%). CONCLUSIONS: In medical ICU patients undergoing planned extubation after a successful SBT, higher NIF was independently associated with lower odds of extubation failure. IMPLICATIONS FOR CLINICAL PRACTICE: These findings support the use of ventilator-measured NIF as a practical adjunct to the multifactorial extubation assessment within standardized weaning programs.