Percutaneous losses of nitrous oxide, cyclopropane, ether and halothane were determined in patients undergoing elective surgical procedures. After 100 minutes of anesthesia, the percutaneous loss of nitrous oxide was 3.6 ml/min/m2 at an average alveolar concentration of 70 per cent, and cyclopropane loss was 0.22 ml/min/m2 at an average alveolar concentration of 15 per cent. After 60 minutes of anesthesia, halothane loss at an alveolar concentration of 0.9 per cent was 0.007G ml/min/m2. Ether loss after 60 minutes at an alveolar concentration of 4 per cent was 0.15 ml/ min/m2. These losses represent only a small fraction of anesthetic uptake after 60-100 minutes of anesthesia; the largest fraction of total uptake, 6.4 per cent, was obtained with nitrous oxide. Percutaneous loss of nitrous oxide increased in a rectilinear manner, with a fivefold increase as skin temperature rose from 20 to 40 C. Our data suggest diffusion is more important than cutaneous blood flow in limiting loss of anesthetic through the skin.
(C) 1969 American Society of Anesthesiologists, Inc.