The Effect of Fresh Gas Flow on Paco2 in General Anesthesia

The effect of fresh gas tlow on PaCo2, was studied on 15 children who given general anesthesia for surgery. Each patient was his/her own control Arterial blood samples were drawn to measure PaCo2. First sample was taken 15 minutes and the second sample 30 minutes after the patient was anesthetised. Gas flow increased by 500 ml, and the 3rd sample taken after 15 minutes. The mean PaCo2, showed a fall of 4 min.Hg (11.7%), in the 3rd sample, (P= <0.01). This study shows that increasing the fresh gas flow causes a fall in PaCo2, if the respiratory rate is kept constant.