Journal Article

Monitoring diaphragmatic effort during diaphragm neurostimulation-assisted ventilation

Thakkar, Viral, Morris, Idunn S., Ferguson, Niall D., Goligher, Ewan C., Parrilla-Gómez, Francisco José, Mehta, Nawzer, Brochard, Laurent J., Madormo, Matías, Bellissimo, Catherine A., Bassi, Thiago, Castellvi-Font, Andrea

2025

Overview

Rationale Diaphragm neurostimulation-assisted ventilation (DNAV) can improve cardiopulmonary function during passive mechanical ventilation. However, this technique requires a reliable method to monitor and titrate diaphragmatic loading to avoid both insufficient and excessive diaphragmatic stimulation. Objective To establish whether the reduction in airway pressure-time product (ΔPTPaw) obtained during diaphragm neurostimulation in assist control volume-controlled mode accurately quantifies the magnitude of respiratory muscle effort elicited by neurostimulation. Methods This was a secondary analysis of the STIMULUS trial. Diaphragm neurostimulation was titrated across four levels targeting progressive occlusion pressures of 0, − 5, − 10, and − 15 cm H₂O at two PEEP levels. At each level, airway, esophageal, and gastric pressures were recorded to compute transdiaphragmatic pressure-time product (PTPdi), respiratory muscles pressure-time product (PTPmus), and ΔPTPaw, defined as the difference in airway pressure-time product between non-stimulated and stimulated breaths. Linear mixed-effects models, Bland–Altman analyses, and receiver operating characteristic (ROC) curves were used to assess agreement and discriminative ability. Measurements and main results Twelve patients contributed 494 high-quality respiratory cycles (63% of recorded cycles). Valid Pdi data were available in nine patients. Increasing neurostimulation was associated with higher PTPdi and PTPmus and a corresponding reduction in PTPaw. ΔPTPaw was correlated with both PTPdi (R² = 0.82) and PTPmus (R² = 0.92), with good agreement observed (limits: − 4 to 44 cm H₂O·s/min for PTPdi, and − 5 to 39 cm H₂O·s/min for PTPmus). ΔPTPaw demonstrated excellent discrimination for inadequate (area under receiver operating characteristic curve, AUROC ≥ 0.94) and excessive (AUROC ≥ 0.86) diaphragmatic effort. Conclusions ΔPTPaw is a reliable, non-invasive surrogate for monitoring diaphragm loading during DNAV under assist-controlled volume-controlled mode and may guide neurostimulation titration in mechanically ventilated patients.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V
• Subject: Acute respiratory distress syndrome / Aged / Catheters / Clinical outcomes / Critical Care Medicine / Diaphragm (Anatomy) / Diaphragm - physiology / Electric Stimulation Therapy - methods / Emergency Medicine / Esophagus / Female / Humans / Intensive / Lung diseases / Male / Medicine / Medicine & Public Health / Middle Aged / Monitoring, Physiologic - methods / Patients / Physiology / Pneumonia / Positive-Pressure Respiration - methods / Regulatory approval / Respiration, Artificial - methods / Respiratory failure / Respiratory system / Software / Ventilators / Workloads