Prospective in-depth analysis of anaesthetic management of spontaneous ventilation VATS for lung cancer resection: a matched pairs comparison to intubated VATS.

Abstract

Background: Spontaneous ventilation video-assisted thoracoscopic surgery (SV-VATS) has been propagated for nearly two decades without a prospective in-depth analysis of anaesthetic management and anaesthetic processing times. This would be important as anaesthetic management of SV-VATS imposes fundamental changes to standards in thoracic anaesthesia and may increase anaesthetic risks. Therefore, this study aimed to provide such in-depth analysis and compare the results to data from matched intubated VATS (I-VATS) patients. 3D-reconstruction of bronchial airways helped to estimate the risk reduction by avoiding double-lumen tube (DLT) intubation according to common selection methods in SV-VATS patients.

Methods: SV-VATS patients receiving anatomical (N = 22) and non-anatomical (N = 16) lung cancer resections were prospectively enrolled. A retrospective I-VATS control cohort (N = 76) allowed for a 2:1 propensity score matching. DLT sizes necessary for SV-VATS patients according to common selection methods were evaluated by 3D-reconstruction of the left main bronchus and the ≥ 1 mm criterion.

Results: SV-VATS patients required substantially less propofol dosage (P < 0.001) with an increase in variability of drug dosing (P < 0.001) and higher BIS values (P < 0.001) as compared to I-VATS patients. SV-VATS lead to higher variability in respiratory parameters (P < 0.001) with less driving pressure (P < 0.001) and similar mean tidal volumes, oxygenation, and hemodynamic parameters compared to I-VATS. Spontaneous ventilation was achieved by allowing for permissive hypercapnia and respiratory acidosis. Anaesthetic processing time was reduced by 7 min (P < 0.001). 5-10% of female and 5% of male patients would have received a DLT larger than their bronchial airway.

Conclusions: Our study provides the first prospective quantitative in-depth analysis of a standardised anaesthetic management regime for SV-VATS, including anaesthetic processing times. Respiratory parameters during SV-VATS are compatible with reduced mechanical power as compared to patients undergoing I-VATS. The anaesthetic management regime reduced the risk of airway damage imposed by choosing too-large DLTs in up to 10% of patients without compromising oxygenation and hemodynamic stability. Changes in anaesthetic processing time by 7 min would not allow for a higher caseload of SV-VATS for lung cancer surgery.

Clinical trial number: Not applicable.