No change in serum melatonin, or plasma beta-endorphin levels after sevoflurane anesthesia

To investigate the effect of sevoflurane as single anesthetic on melatonin and beta-endorphin plasma levels during the first 24 hours postoperatively.

Prospective, open-cohort study.

University hospital.

13 ASA physical status I and II, adults, scheduled for dilatation and curettage of the uterus, and 13 healthy volunteers.

Patients received general anesthesia with sevoflurane.

Melatonin and beta-endorphin plasma levels were determined before anesthesia, immediately after, and two, 4, 8, and 24 hours after the end of anesthesia. Melatonin and beta-endorphin were also measured in 13 healthy subjects (controls) not undergoing anesthesia at similar times during the day. Systolic and diastolic blood pressure, heart rate, bispectral index, and oxygen saturation via pulse oximeter (SpO(2)) were recorded before and after anesthesia. Quality of sleep postoperatively was also assessed.

Melatonin levels (pg/mL) in the patients and controls were 8.2 +/- 7.9 versus 15.2 +/- 15.0 before anesthesia and 7.7 +/- 7.9 versus 11.1 +/- 7.0, 6.5 +/- 6.1 versus 15.6 +/- 16.3, and 19.5 +/- 17.9 versus 23.7 +/- 23.3 at the end of anesthesia and 4 and 24 hours after the end of anesthesia, respectively (P = 0.057). At the same time points, beta-endorphin plasma levels (pmol/L) in patients and controls were 5.2 +/- 2.0 versus 4.0 +/- 2.3, 5.4 +/- 3.3 versus 3.9 +/- 2.5, 4.9 +/- 1.2 versus 4.4 +/- 1.7, and 3.7 +/- 2.6 versus 4.2 +/- 1.8, respectively (P= 0.285). The quality of sleep assessed clinically was not altered.

Sevoflurane as a single anesthetic for minor gynecological procedures did not influence significantly melatonin or beta-endorphin plasma levels. Sleep quality assessed clinically was not influenced.