Comparison of breathing tube connectors during invasive bronchial procedures

Bronchoscopy and bronchial suctioning during intra-operative artificial ventilation often causes leakage from the ventilation circuit with a decrease in ventilatory parameters and possible workplace contamination with anaesthetic gases. Different connectors have been developed to reduce gas leakage. We evaluated the following connectors : VBM 2 mm, 3 mm and 5 mm, Bodai Suction-Safe, Bodai Bronch-Safe and Bodai Trach-Safe, as well as the BE 105-7, BE 105-8 and SH 7-45. Invasive bronchial instruments (catheters, bronchoscopes and bronchial blockers) with 1.67-7.33 mm diameter were used. Pressure-controlled ventilation was performed on a test lung using a ventilator. Sevoflurane concentration in the room was measured 0.2 and 1.5 m from the connector using a photo-acoustic infrared-spectroscope. The VBM connectors caused the least gas leak and ensured stability of ventilation parameters even at peak pressures when combined with smaller instruments. With instruments > 6 mm, BE 105-7, BE 105-8 and SH 7-45 connectors performed best. The Bodai connectors showed a reduced ability to prevent leakage and to keep ventilatory parameters stable. All connectors, excluding the Bodai Trach-Safe, prevented exposure to anaesthetic gases beyond the current safety recommendations when combined with the fitting instruments. The connectors showed different ranges of tightness, equivalent to different ranges of compatibility with the instruments used.