Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Anesthesia/OR Economics
A major determinate of volatile anesthesia cost is fresh-gas flow rate. [1,2] High-gas flows used in children speed induction and emergence. However, lower flow rates during maintenance of anesthesia could substantially reduce cost. Compound A levels at 2 L/min flow in pediatric patients have been shown to be low.  Volatile anesthetic cost has been estimated in selected populations of adult outpatients  and at high flows in ambulatory pediatric patients.  This study examines outcome and cost of sevoflurane anesthesia in children at flow rates above and below 2 L/min.
After Human Investigation Committee approval, prospective collection of operating room (OR) and postanesthesia recovery room (PACU) data on all surgical cases performed at Grady Memorial Hospital over a four-month period of normal practice was undertaken. Patients, 2-12yo, receiving general anesthesia with sevoflurane and were extubated by PACU discharge were included. OR narcotic use was measured in fentanyl equivalents/kg based on known analgesic equivalence ratios. Sevoflurane use during maintenance was calculated from measured end-tidal concentrations. Reaching and maintaining a modified Aldrete score  of 17/20 x 30min was considered criteria for PACU discharge. Intravenous medication in the PACU was monitored. (Table 1)
No differences existed between groups with regard to demographic variables or emergent cases. Nitrous oxide use (94%), caudal anesthesia (6-10%) and ketorolac administration were similar (0.2-0.4mg/kg). The low-flow group received significantly more intra-operative narcotic (240%). Duration of volatile administration, end-tidal concentration and MAC-h were not significantly different. Sevoflurane use was doubled (213%) in the high-flow group with significantly higher cost. Recovery time and number of PACU interventions were not significantly different. A tendency toward lower extubation times in the low-flow group was noted (p < 0.07) with low statistical power (44%).
Fresh-gas flow rate was the prime determinate of increased cost. Despite higher intraoperative narcotic use, the low-flow group had a tendency toward shorter extubation times. Other clinical outcomes were not influenced by flow rate. Small changes in total gas flow during anesthetic maintenance resulted in a significant reduction in direct cost of sevoflurane without shifting indirect costs. (Table 2 and Table 3)
1. Anaesthesia 1995;50:37-44
2. Anesthesiology 1993;79:1413
3. Anesthesiology 1996;84:566-71
4. Anesth Analg 1995;81:S67-72
5. Anesth Analg 1996;83:917-20
© 1998 International Anesthesia Research Society
6. Can Anaesth Soc J 1975;22:111