Early Inspiratory Effort Assessment by Esophageal Manometry Predicts Noninvasive Ventilation Outcome in De Novo Respiratory Failure. A Pilot Study

Abstract

Rationale: The role of inspiratory effort still has to be determined as a potential predictor of noninvasive mechanical ventilation (NIV) failure in acute hypoxic de novo respiratory failure.Objectives: To explore the hypothesis that inspiratory effort might be a major determinant of NIV failure in these patients.Methods: Thirty consecutive patients with acute hypoxic de novo respiratory failure admitted to a single center and candidates for a 24-hour NIV trial were enrolled. Clinical features, tidal change in esophageal pressure (ΔPes), tidal change in dynamic transpulmonary pressure (ΔPl), expiratory Vt, and respiratory rate were recorded on admission and 2-4 to 12-24 hours after NIV start and were tested for correlation with outcomes.Measurements and Main Results: ΔPes and ΔPes/ΔPl ratio were significantly lower 2 hours after NIV start in patients who successfully completed the NIV trial (n = 18) compared with those who needed endotracheal intubation (n = 12) (median [interquartile range], 11 [8-15] cm H₂O vs. 31.5 [30-36] cm H₂O; P < 0.0001), whereas other variables differed later. ΔPes was not related to other predictors of NIV failure at baseline. NIV-induced reduction in ΔPes of 10 cm H₂O or more after 2 hours of treatment was strongly associated with avoidance of intubation and represented the most accurate predictor of treatment success (odds ratio, 15; 95% confidence interval, 2.8-110; P = 0.001 and area under the curve, 0.97; 95% confidence interval, 0.91-1; P < 0.0001).Conclusions: The magnitude of inspiratory effort relief as assessed by ΔPes variation within the first 2 hours of NIV was an early and accurate predictor of NIV outcome at 24 hours.Clinical trial registered with www.clinicaltrials.gov (NCT03826797).

Keywords: acute respiratory distress syndrome; esophageal pressure swings; noninvasive mechanical ventilation; respiratory failure; transpulmonary pressure.

Figure 1.

Flowchart for patients in this study. ΔPes = tidal change in esophageal pressure; ΔPl = tidal change in transpulmonary pressure; DRF = de novo respiratory failure; IOT = intubation (orotracheal); MV = mechanical ventilation; NIV = noninvasive MV; NM = neuromuscular; RICU = respiratory ICU.

Figure 2.

(A) ΔPes changes from baseline within the first 2 hours of NIV for the whole population and according to NIV outcome at 24 hours. (B) ΔPl changes from baseline within the first 2 hours of NIV for the whole population and according to NIV outcome at 24 hours. ΔPes = tidal change in esophageal pressure; ΔPl = tidal change in transpulmonary pressure; NIV = noninvasive mechanical ventilation.

Figure 3.

Graphical representation of ΔPl and ΔPes waveform swings after 2 hours of NIV for (A and C) a patient who had failure in the noninvasive mechanical ventilation trial at 24 hours and for (B and D) a patient who had success. The beginning of the inspiratory phase was identified at the time of Pes initial decay, whereas the end of inspiration was considered at the point of Pes that elapsed 25% of time from its maximum deflection to return to baseline. ΔPes = tidal change in esophageal pressure; ΔPl = tidal change in dynamic transpulmonary pressure.

Figure 4.

Receiver operating characteristic analysis. Tidal change in esophageal pressure changes < 10 cm H₂O within the first 2 hours of noninvasive mechanical ventilation showed a high accuracy in predicting noninvasive mechanical ventilation failure (AUC, 0.97; P < 0.0001). AUC = area under the curve; CI = confidence interval.