General anesthesia and the ketogenic diet: clinical experience in nine patients

PURPOSE: To determine if children actively on the ketogenic diet (KD) can safely undergo general anesthesia (GA) for surgical procedures. METHODS: The records of children treated with the KD at Children's Hospital (Boston, Massachusetts) from 1995 to the present were reviewed. The charts of children who had received GA while on the diet were evaluated with regard to demographics, procedure information, anesthesia records, blood chemistries, and perioperative course. Of 71 children on the KD during the period of the study, nine (12.7%) had procedures requiring GA while on the diet. RESULTS: Nine children received GA for surgical procedures ranging from central line placement to hemispherectomy while on the KD. At the time of GA, the children ranged from age 1 to 6 years, and had been on the KD for 2-60 months. The patients received carbohydrate-free intravenous solutions perioperatively. Anesthesia duration ranged from 20 min to 11.5 h; for longer procedures, serum pH, glucose, and electrolyte levels were monitored. Serum glucose levels remained stable in all patients, but serum pH typically decreased; the largest reduction was to 7.16. In three procedures, patients received intravenous bicarbonate because of level of acidosis. There were no perioperative complications. CONCLUSIONS: Children on the KD can safely undergo GA for surgical procedures. Although serum glucose levels appear to remain stable, serum pH or bicarbonate levels should be monitored because of the risk of metabolic acidosis.