Saliva cyclic GMP increases during anaesthesia

Background. Cyclic GMP (cGMP) has been implicated in modulatingthe effects of general anaesthesia. Changes in cGMP in humansundergoing anaesthesia have not been reported previously. Methods. In this pilot study we measured cGMP in the salivaof six healthy volunteers and eight patients undergoing generalanaesthesia for minor gynaecological procedures. Samples wereobtained using a commercially available sampling device andcGMP was determined with an enzyme immunoassay and results expressedas a cGMP per mg protein. Results. There was no statistically significant variation insalivary cGMP either day-to-day or between time points in healthyvolunteers. Analysis of variance of salivary cGMP of patientsundergoing general anaesthesia showed that cGMP increased significantlyintraoperatively and returned to preoperative levels after surgery(P=0.03). Conclusions. This is the first time that real time in vivo changesin salivary cGMP levels during general anaesthesia in humanshave been demonstrated and may allow an alternative techniquefor measuring depth of anaesthesia in the future. Br J Anaesth 2002; 89: 635–7