INCIDENCE OF MALPOSITION OF POLYVINYLCHLORIDE AND RED RUBBER LEFT-SIDED DOUBLE-LUMEN TUBES AND CLINICAL SEQUELAE

Currently, fiberoptic bronchoscopy (FB) is recommended for correct pos itioning of double-lumen endobronchial tubes (DLTs) because of the hig h incidence of malpositions not appreciated by clinical signs. The aim s of this study were to assess whether clinical signs allow accurate c onfirmation of adequate positioning with left red rubber (RR) or polyv inylchloride (PVC) double-lumen tubes and to compare the incidence of malpositions between the two tubes. Another goal was to assess whether these malpositions, not appreciated by clinical assessment, adversely affected outcome. Twenty-one adult patients scheduled for elective th oracic surgery were randomly assigned to the RR (11 patients) or PVC g roup (10 patients). After endobronchial intubation, the position of th e tubes was adjusted until clinically satisfactory lung separation had been achieved. A single investigator performed all the FB and assesse d adequacy of tube placement. Clinical and FB assessments were perform ed in the supine (SUP) and lateral positions. The anesthesiologists re sponsible for the clinical evaluation were ''blinded'' to the bronchos copic findings. While in the SUP position, the tube was ''too deep'' t o permit visualization of the carina during tracheal bronchoscopy in 5 patients (2 RR, 3 PVC). In 17 of 21 (10 RR, 7 PVC), the bronchial cuf f could not be visualized, although in 1 patient (RR group), the cuff was overinflated and bulged out to partially obstruct the right main b ronchus orifice. Bronchial bronchoscopy showed 4 of 11 patients in the RR group in whom the left upper lobe orifice was occluded compared wi th 1 only in the PVC group. The PVC did not differ from the RR in case s in which the tube was ''too far out.'' However, they did differ in t he incidence of the tube being pushed too far in 36% in the RR versus 10% in the PVC (p < 0.05). The comparisons between the means of PaO2, PaCO2, tidal volume, and the peak airway pressures in all the patients in the PVC versus the RR DLT groups show no differences between the 2 groups. In the cases of malpositioned tubes, there were no statistica l differences in PaO2 between the right and left thoracotomies during two-lung ventilation (2LV) or one-lung ventilation (OLV) (520 +/- 80 v 469 +/- 56 mmHg and 167 +/- 105 v 325 +/- 94 mmHg, respectively). In the well-positioned tubes, the comparison between right and left thora cotomies showed no statistical differences in PaO2, (432 +/- 114 v 464 +/- 71 mmHg during 2LV and 182 +/- 104 v 157 +/- 94 mmHg during OLV, respectively). The results of this study show that, first, there is no significant difference in ventilation between the PVC and the RR tube s as measured by PaCO2, peak airway pressure, and tidal volume. Second , a similar incidence of malpositions was found in both groups in the supine and lateral decubitus positions except for a higher incidence o f malposition in the RR group in which the bronchial carina was not vi sualized during bronchial bronchoscopy. Finally, the patients with mal positioned tubes had similar arterial oxygen saturation to patients wi th well-positioned tubes, whether the patients were undergoing right o r left thoracotomies. Copyright 1995 by W.B. Saunders Company