Overinflated sensibilities?

It seems about once every 18 months that my faith in medical practitioners is shaken. Today was such a day. I was called in to look at a ventilator I'd just serviced. They said "the gases are dropping" which meant nothing to me. Turned out the anaesthetic levels kept going lower when they tried to ventilate with the machine. I checked the machine and it was fine. Then I looked at the breathing circuit and asked if that's what they had been using. I was told yes. I pointed out that if they used that type of circuit then there would be fresh oxygen introduced to the patient which would dilute the other gases and that I was surprised the anaesthetist hadn't worked that one out. We aren't talking complicated stuff here - just basic common sense. A child could understand it. When the theatre manager started talking about low flows and alveoli I knew I was wasting my breath and that,  either he knew as much as the anaesthetist, or he was covering an arse. The worrying thing is that these people are the ones keeping you alive on the operating table. Thank goodness the eejits are few and far between. Most really know what they are doing.