A COMPARISON OF THE RELIABILITY OF 2 TECHNIQUES OF LEFT DOUBLE-LUMEN TUBE BRONCHIAL CUFF INFLATION IN PRODUCING WATERTIGHT SEAL OF THE LEFTMAINSTEM BRONCHUS

A double-lumen endobronchial tube (DLT) bronchial cuff inflation techn ique that reliably ensures effective water-tight isolation of the two lungs has not been determined. In this study, 20 patients undergoing t horacic surgery requiring a left DLT had the bronchial cuff of the DLT inflated by one of two techniques. In Group 1, the cuff was inflated to produce an air-tight seal of the left bronchus using the underwater seal technique. In Group 2, the cuff was inflated to a pressure of 25 cm H2O. After bronchial cuff inflation in both groups, water-tight br onchial seal was tested by instilling 2 mt of 0.01% methylene blue (MB ) above the bronchial cuff of the DLT. Fifteen minutes later, fiberopt ic bronchoscopy was performed via the bronchial lumen of the DLT to de termine whether MB had seeped past the bronchial cuff. Cuff volume was 0.75 +/- 0.64 and 0.76 +/- 0.46 mt, cuff pressure was 30.1 +/- 27.0 a nd 25.0 +/- 0.0 cm H2O (mean +/- SD), and MB was positively identified in two and five patients in Groups 1 and 2, respectively. The differe nce in cuff volume and pressure and the higher MB seepage in Group 2 c ompared with Group 1 was not statistically significant. Ln both groups , MB seepage occurred only when the bronchial cuff volume was <1 mt an d when the patients were positioned in the left lateral decubitus posi tion. These findings suggest that the risk of aspiration is greatest w hen the DLT is positioned in the dependent lung and when the bronchial cuff volume is <1 mt. Implications: Water-tight sealing of the left b ronchus by DLT bronchial cuff was tested after cuff inflation using tw o different techniques. Neither air-tight bronchial seal nor cuff pres sure of 25 cm H2O guaranteed protection against aspiration. The risk o f aspiration was greatest when the DLT was positioned in the dependent lung and when the bronchial cuff volume was <1 mL.