In Reply:—

We wish to thank the editor for allowing us to reply to Dr. Blinder's correspondence. 1 

As stated in our case report 2we have eliminated heated circuits from our anesthesia machines that have the SmartVent 7900 ventilator (Datex-Ohmeda, Madison, WI). This has dramatically decreased the problem described in our case report.

We agree with Dr. Blinder that low gas flows contribute to the condensation in the ventilator sensor. However, we feel that ambient temperature plays a minor role in sensor malfunction. The Smart Vent 7900 anesthesia machines are used extensively in our trauma rooms, which are kept warm to avoid patient heat loss. We have experienced the same rate of sensor malfunction in these suites compared with our regular operating room suites, which are kept much cooler. We do find that long cases, over 3 to 4 h, play a role in the sensor malfunctioning. Recently, one of the system integration boards (SIB) was replaced on one of the anesthesia machines used in one of the trauma rooms.

The revised flow sensors from Datex-Ohmeda minimize the moisture buildup that cause the sensors to fail. We have had a very good experience with them.

Binder JL, Ambient OR: Temperatures and Datex-Ohmeda 7900 SmartVent Malfunction: Letter to the Editor, A nesthesiology 2002; 97: 1645
Cantillo J, Domsky R, Domsky R, Goldberg M: Ventilatory Failures with the Datex-Ohmeda 7900 Smart Vent. A nesthesiology 2002; 96: 766–768