Ventilator induced diaphragm dysfunction : incidence and influence on weaning

Position du problème et objectif(s) de l’étude

In the Intensive care unit (ICU), mechanical ventilation (MV) is associated with numerous complications including ventilator-induced diaphragmatic dysfunction (DD). Diaphragm ultrasound is a valuable, non-invasive tool for assessing diaphragm contractility in critically ill patients. The aim of our study was to compare diaphragm contractility in ventilated versus spontaneously breathing patient and to determine its impact on morbidity and mortality.

Matériel et méthodes

We conducted a prospective, observational ultrasound-based study involving adult ICU patients divided into two groups: the spontaneous breathing (SB) group and the mechanically ventilated (MV) group, with 40 patients in each. Diaphragm thickening fraction (DTF) was measured using ultrasound on the right zone of apposition between 48 hours and 5 days after ICU admission (SB group) or initiation of MV (MV group). Patients with known risk factors for diaphragm dysfunction (e.g., neuromuscular diseases, ascites, pregnancy) were excluded. Diaphragm thickness during inspiration (ETI) and expiration (ETE) was measured in anterior, medial, and posterior regions along the mid-axillary line. DTF was calculated as follows: DTF = (ETI – ETE) / ETE × 100. DTF values were compared between groups and analyzed for associations with weaning outcomes and mortality.

Résultats & Discussion

Both groups were demographically comparable, although the MV group was significantly younger. Diaphragm dysfunction was more frequent in the MV group, with significantly lower DTF values. DTF was correlated with the timing of ultrasound assessment. Weaning failure was associated with low DTF values, and a DTF > 44.56% was predictive of weaning success (AUC = 0.727 [0.556–0.899], sensitivity = 100%, specificity = 50%, PPV = 73.3%, NPV = 100%). Mortality was higher in the MV group, and a DTF < 27.09% was predictive of death (AUC = 0.657 [0.539–0.762], sensitivity = 50%, specificity = 82.1%, PPV = 50%, NPV = 82.1%). Multivariate analysis identified pulmonary sepsis as an independent risk factor for diaphragm dysfunction.

Conclusion

Diaphragm contractility is impaired within the early days of mechanical ventilation. Reduced DTF values were associated with weaning failure, prolonged ICU and hospital stays. In our study, a DTF value inferior to 44.56% was predictive of weaning failure and a value inferior to 27.09% was predictive of death.

Auteurs

Eya BEN AMRI, Haythem ELASKRI, Islem BERRIMA, Abir GHARBI, Soumaya ZAABAAR, Arine AOUADI, Malek KHASKHOUSSI, Sofia BEN MOUSSA, Rihem KOUSI, Ines ISSAOUI, Imen NAAS, Iheb LABBENE - (1)Hôpital Militaire Principal D'instruction De Tunis, Tunis, Tunisie

Orateur(s)

Haythem ELASKRI (Tunis)