Postoperative acute respiratory distress syndrome. A complication of amiodarone associated with 100 percent oxygen ventilation.

Communications to the Editor this device in a previously reported randomized study.’ The methods we used2 to perform MV were nearly the same as those used in that study, but the strategies of tracheal aspiration and instillation were quite different. We performed tracheal aspiration systematically at least every 4 h. This strategy led us to instill 30±12 mIld in the heated-humidifier (Hil) group and 40±20 mEld in the HME group. In the study by Martin et al,’ HH patients received 223 instillations of 5 ml for 589 days of MV (approximately 2.5 mIld), and HME patients received 300 instillations for 299 days of MV (5 mIld); ten of the 31 HME patients were not given any instillation. Since we performed our study, we have used the Pall HME routinely in 560 consecutive patients for a total of 5,880 days of MV, using the same methods as those described in our article.2 No fatal tube occlusion occurred during this period, and difficulty in suctioning resulted in replacement of the HME by an HH in 14 patients (unpublished data). In contrast to the study period, the use of fiberoptic bronchoscopy as a method of detection of “occult” tube clubbing was not systematic in these more recent patients. The assertion by Dr Sottiaux that tube occlusion is not completely prevented by tracheal instillations is based on the results of Martin et al,’ as well as on a case report of tracheal obstruction with a bronchial cast following MV with a Servo SH 150 humidifier. In the latter case, the patient was given only 3 ml of saline solution twice a day for four days, and the incidence of such an accident is not mentioned, No consensus is currently available about the value of periodic instillations into the tracheal tubes of MV patients, a single study’ having prospectively addressed this point. In that randomized study, Pall HMEs were used for all patients, and tube resistances measured at extubation were significantly lower in patients who underwent tracheal aspirations and instillations than in those who underwent only aspirations. Therefore, tracheal instillations might increase the efficiency of HMEs in preventing tube occlusion by humidifying tracheal secretions, so that we do not agree that the populations studied by Martin et al’ and by us2 are equivalent regarding the management of the tracheal tube. In conclusion, we do not believe that the Pall HME should be definitively avoided in long-term MV unless tracheal management includes a minimal frequency of systematic tracheal aspirations and instillations. However, we agree with Dr Sottiaux that other newly available HMEs could be more appropriate than the Pall BB 2215 HME for long-term MV5 and that those HMEs shot,ld be clinically assessed.