Correspondence  |   July 2005
Valve Leaks with New Disposable Extraglottic Airway Devices
Author Notes
  • Engineered Medical Systems, Indianapolis, Indiana.
Article Information
Correspondence   |   July 2005
Valve Leaks with New Disposable Extraglottic Airway Devices
Anesthesiology 7 2005, Vol.103, 214. doi:
Anesthesiology 7 2005, Vol.103, 214. doi:
In Reply:—
We fully agree with Dr. van Zundert et al.  that manufacturers of extraglottic devices (and all other medical devices) should assure quality control of their products.
Since the CobraPLA® (Engineered Medical Systems, Inc., Indianapolis, IN) was introduced into clinical practice in 2003, Engineered Medical Systems has ensured the quality of the cuff deflator valve with a comprehensive validation and production procedure of every product made, which includes a pressure test of the deflator valve and a full 16-h inflation test of the deflator valve/cuff assembly, with no leakage allowed.
For a manufacturer to fully assess and address a valve issue such as Dr. van Zundert et al.  describe, it is imperative that the products in question be promptly returned to the producer (in its original condition at the time of use) for evaluation. Unfortunately, Engineered Medical Systems never received the six devices in question back at our facility for a proper inspection to be conducted. When we visited Dr. van Zundert in the Netherlands after receiving a copy of his correspondence to Anesthesiology, we were presented with a bundle of more than 30 CobraPLAs®, which had been used and then cleaned. There was no documentation as to which ones had been used in his report. As a result, we cannot be certain as to the cause of the failures.
Considering the fact that Engineered Medical Systems has not received a single other report of a cuff deflator valve failure from all the units distributed worldwide, we might assume that a very limited number of devices (the ones used by Dr. van Zundert et al.  ) had a minimal leak that could not be identified at preoperative check. Alternatively, we have been notified by another investigator that in some units, during continuous cuff pressure monitoring, a small leak can occur at the monitoring connection site and not from the device itself  ; that clinician did not think that the valve was malfunctioning. Finally, damage to the devices in question could have also occurred during forceful cleaning before the postuse submersion test. It is reassuring to Engineered Medical Systems that the deflated cuff did not influence the clinical performance of the device or the end-tidal carbon dioxide measurement during the study of Dr. van Zundert et al.  , which speaks highly to the performance of the CobraPLA®.
Although we cannot state with certainty that the experience of Dr. van Zundert et al.  was unique, it seems that it was isolated and that valve failure has not posed a significant clinical problem for clinicians. We are confident that the CobraPLA® meets the rigorous quality standards clinicians and patients deserve in their medical products.
Engineered Medical Systems, Indianapolis, Indiana.