Non-invasive method to detect high respiratory effort and transpulmonary driving pressures in COVID-19 patients...

High respiratory drive in mechanically ventilated patients with spontaneous breathing effort may cause excessive lung stress and strain and muscle loading. Therefore, it is important to have a reliable estimate of respiratory effort to guarantee lung and diaphragm protective mechanical ventilation. Recently, a novel non-invasive method was found to detect excessive dynamic transpulmonary driving pressure (∆P_L) and respiratory muscle pressure (P_mus) with reasonable accuracy. During the Coronavirus disease 2019 (COVID-19) pandemic, it was impossible to obtain the gold standard for respiratory effort, esophageal manometry, in every patient. Therefore, we investigated whether this novel non-invasive method could also be applied in COVID-19 patients.

∆P_L and P_mus were derived from esophageal manometry in COVID-19 patients. In addition, ∆P_L and P_mus were computed from the occlusion pressure (∆P_occ) obtained during an expiratory occlusion maneuver. Measured and computed ∆P_L and P_mus were compared and discriminative performance for excessive ∆P_L and P_mus was assessed. The relation between occlusion pressure and respiratory effort was also assessed.

Thirteen patients were included. Patients had a low dynamic lung compliance [24 (20-31) mL/cmH₂O], high ∆P_L (25 ± 6 cmH₂O) and high P_mus (16 ± 7 cmH₂O). Low agreement was found between measured and computed ∆P_L and P_mus. Excessive ∆P_L > 20 cmH₂O and P_mus > 15 cmH₂O were accurately detected (area under the receiver operating curve (AUROC) 1.00 [95% confidence interval (CI), 1.00-1.00], sensitivity 100% (95% CI, 72-100%) and specificity 100% (95% CI, 16-100%) and AUROC 0.98 (95% CI, 0.90-1.00), sensitivity 100% (95% CI, 54-100%) and specificity 86% (95% CI, 42-100%), respectively). Respiratory effort calculated per minute was highly correlated with ∆P_occ (for esophageal pressure time product per minute (PTP_es/min) r² = 0.73; P = 0.0002 and work of breathing (WOB) r² = 0.85; P < 0.0001).

∆P_L and P_mus can be computed from an expiratory occlusion maneuver and can predict excessive ∆P_L and P_mus in patients with COVID-19 with high accuracy.