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

Background

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

Methods

∆ 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

Results

Thirteen patients were included. Patients had a low dynamic lung compliance [24 (20–31) mL/cmH_2O], high ∆ P _L (25 ± 6 cmH_2O) and high P _mus (16 ± 7 cmH_2O). Low agreement was found between measured and computed ∆ P _L and P _mus. Excessive ∆ P _L > 20 cmH_2O and P _mus > 15 cmH_2O 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) r ^2 = 0.73; P  = 0.0002 and work of breathing (WOB) r ^2 = 0.85; P  < 0.0001)

Conclusions

∆ 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.