To the Editor:
We report an unusual cause of endotracheal tube (ETT) cuff deflation. A 72-yr-old patient with severe rheumatoid arthritis was orally intubated with a Mallinckrodt 7.0 ETT. The correct position of the tube was verified, the cuff inflated, and positive pressure ventilation instituted. After 2 min, leakage of gas around the cuff was audible. The tube position was rechecked, and additional air was added to the cuff. After 2 more min leakage was again apparent. The tube was removed and replaced by another 7.0 ETT, and the procedure continued uneventfully.
Examination of the original ETT revealed no defect to the naked eye. On inflation of the cuff, there was no apparent air leak. However, immersion in water revealed a leak at the point where the pilot tube becomes incorporated into the wall of the ETT Figure 1, a site previously unreported.
Analysis has indicated that malposition is the most likely cause of ETT leakage, but that those tubes with mechanical defects were defective either at the cuff or at the pilot valve . Additionally, the cuff and pilot tube may be damaged by snagging on the teeth. In this case, the patient was edentulous, the ETT had been inspected and inflated prior to use, and the correct position of the tube had been verified.
We conclude that in this instance routine inspection of the ETT and inflation of the cuff failed to detect a significant air leak. Only on immersion in water did the leak become obvious; such a test would not be practical prior to insertion of all ETTs. Although inspection prior to use is essential, we reaffirm that clinical assessment by the anesthesiologist is the most important factor in confirming tube function.
Thomas A. Gettelman, MD
Geoffrey N. Morris, MB, BS, FRCA
Department of Anesthesiology, University of Virginia, Charlottesville, VA 22901
1. Kearl RA, Hooper RG. Massive airway leaks: an analysis of the role of endotracheal tubes. Crit Care Med 1993;21:518-21.