Fasting or starving? Measurement of blood ketone levels in 100 fasted elective and emergency adult surgical patients at an Australian tertiary hospital

Anaesth Intensive Care. 2018 Sep;46(5):463-467. doi: 10.1177/0310057X1804600506.


Prolonged fasting leads to a shift from carbohydrate to fat as the primary energy source, resulting in the production of ketones such as beta-hydroxybutyrate. Hyperketonaemia and ketoacidosis have been observed in young children fasting for surgery. The aim of this study was to investigate ketonaemia in adults fasted for surgery. One hundred non-diabetic adults presenting for elective or emergency surgery were assessed for the presence of hyperketonaemia (beta-hydroxybutyrate levels more than 1 mmol/l), and the relationship between beta-hydroxybutyrate, blood glucose and fasting duration was investigated. Three of 100 patients demonstrated hyperketonaemia, one of whom had ingested a ketogenic supplement the evening prior to surgery. No patient demonstrated beta-hydroxybutyrate levels suggestive of ketoacidosis (above 3 mmol/l). No relationship between fasting duration and ketone or glucose levels was observed. We found no evidence that prolonged preoperative fasting led to beta-hydroxybutyrate levels consistent with ketoacidosis.

Keywords: acidosis, hypoglycaemia, child, adult, human; beta-hydroxybutyrate, insulin resistance, ketosis, starvation; fasting, blood glucose, 3-hydroxybutyric acid.

Publication types

  • Observational Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Elective Surgical Procedures
  • Emergencies
  • Fasting*
  • Female
  • Humans
  • Ketone Bodies / blood*
  • Male
  • Middle Aged
  • Preoperative Care*
  • Tertiary Care Centers
  • Young Adult


  • Ketone Bodies