Evaluating lung ventilation via electrical impedance tomography during flexible bronchoscopy with supraglottic jet ventilation: a prospective pilot study.

BACKGROUND

Supraglottic jet ventilation (SJV) is used during flexible bronchoscopy to improve oxygenation, but its impact on overall lung ventilation is unclear. Thoracic electrical impedance tomography (EIT) offers real-time monitoring of respiratory function.

METHODS

This prospective pilot study enrolled patients undergoing flexible bronchoscopy. End-expiratory lung impedance (EELI) changes from baseline (ΔEELI) were measured at baseline (T0), oxygenation with Wei nasal jet (WNJ) (T1), SJV (T2), during bronchoscopy (T3), and post-bronchoscopy (T4). The primary outcome was ΔEELI at T2 vs. T3. Secondary outcomes included ΔEELI at other time points, ventilation distribution (ventral vs. total lung, ROIventral), hemodynamics, oxygen saturation (SpO2) at each point, and adverse events.

RESULTS

Among 27 patients, 5 experienced transient desaturation (no laryngeal mask ventilation needed). ΔEELI and SpO2 significantly decreased from T2-T3 (ΔEELI: -2.65, 95% CI -4.27 to -1.02, p < 0.001; SpO2: -2.5%, 95% CI -4.7 to -0.3%, p < 0.001). Conversely, ΔEELI and SpO2 significantly increased from T1-T2 (ΔEELI: 1.84, 95% CI 1.02-2.66, p < 0.001; SpO2: 3.3%, 95% CI 1.3-5.2%, p < 0.001), with ROIventral rising from 43.7 to 60.4% (16.6% increase, 95% CI 4.4-28.9%, p < 0.001).

CONCLUSIONS

While SJV did not prevent the negative effects of bronchoscopy on lung ventilation and oxygenation, it maintained adequate SpO2. Pre-bronchoscopy SJV improved these measures, but shifted ventilation towards ventral lung regions compared to WNJ oxygenation.

TRIAL REGISTRATION: Chinese Clinical Trial Registry (URL: Chictr.org.cn), Identifier: ChiCTR2100050285. Date of registration: Aug 25th, 2021.