Comparison of total intravenous anesthesia using propofol and inhalational anesthesia using isoflurane for controlled hypotension in functional endoscopic sinus surgery.

BACKGROUND: An important requirement during functional endoscopic sinus surgery is to maintain a clear operative field to improve visualization during surgery and to minimize complications. MATERIALS AND METHODS: We compared total intravenous anesthesia using propofol with inhalational anesthesia using isoflurane for controlled hypotension in functional endoscopic sinus surgery. It was a prospective study in a tertiary hospital in India. Forty ASA physical status I and II adult patients (16-60 years) were randomly allocated to one of two parallel groups (isoflurane group, n = 20; propofol group, n = 20). The primary outcome was to know whether total intravenous anesthesia using propofol was superior to inhalational anesthesia using isoflurane for controlled hypotension. The secondary outcomes measured were intraoperative blood loss, duration of surgery, surgeon's opinion regarding the surgical field and the incidence of complications. RESULTS: The mean (±SD) time to achieve the target mean blood pressure was 18 (±8) minutes in the isoflurane group and 16 (±7) minutes in the propofol group (P = 0.66). There was no statistically significant difference (P = 0.402) between these two groups in terms of intraoperative blood loss and operative field conditions (P = 0.34). CONCLUSIONS: Controlled hypotension can be achieved equally and effectively with both propofol and isoflurane. Total intravenous anesthesia using propofol offers no significant advantage over isoflurane-based anesthetic technique in terms of operative conditions and blood loss.

Quantifying the effect of isoflurane and nitrous oxide on somatosensory-evoked potentials.

Anaesthetic techniques may have a significant effect on intraoperative-evoked potentials (EP). The present study is designed to compare Propofol anaesthesia with Isoflurane (with or without nitrous oxide) during intraoperative somatosensory-evoked potential (SSEP) monitoring in 15 ASA Grade I and II patients undergoing surgery for intracranial tumours. SSEPs in response to median and posterior tibial nerve stimulation were recorded under four different anaesthetic conditions: 1) Propofol infusion and ventilation with air-oxygen, 2) Isoflurane, 1.0 MAC and ventilation with air-oxygen, 3) Isoflurane 1.0 MAC and ventilation with nitrous oxide-oxygen, and 4) Return to Isoflurane, 1.0 MAC and ventilation with air-oxygen. Intraoperative monitoring of somatosensory evoked potentials is best recordable using Propofol. The morphology of the EP is reproducible with Isoflurane. This effect is exaggerated when it is advisable to avoid nitrous oxide.