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Johansen, JW MD PhD; Mashman, D MD; Starr, M MD

doi: 10.1097/00000539-199802001-00035
Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Anesthesia/OR Economics

Department of Anesthesiology, Emory University School of Medicine, Atlanta, CA 30335.

Abstract S35

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. [3] Volatile anesthetic cost has been estimated in selected populations of adult outpatients [4] and at high flows in ambulatory pediatric patients. [5] 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 [6] of 17/20 x 30min was considered criteria for PACU discharge. Intravenous medication in the PACU was monitored. (Table 1)

Table 1

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)

Table 2

Table 2

Table 3

Table 3

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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
6. Can Anaesth Soc J 1975;22:111
© 1998 International Anesthesia Research Society