Utilization of fresh gases and volatile agents in patients managed using rebreathing systems at Kenyatta national hospital

Abstract

This was a prospective descriptive study on utilization of fresh gases and volatile agents using rebreathing systems in the management of patients at the Kenyatta National Hospital. The objectives were to describe fresh gas flow rates and the factors influencing their administration, establish the cadre difference in anaesthetic practice. estimate the annual costs and establish whether there was a relationship between the amounts administered and the presence of anaesthetic gas analysers. A data collection tool was applied to capture information from participating anaesthetists after obtaining approval from KNH research and ethics committee. The data was stored, verified, cleaned and analysed using Microsoft excel spreadsheet, Statistical Package for Social Sciences (SPSS) and Epi info. A mean fresh gas flow rate of 4.2l1min was administered by a total of 55 anaesthetists to 55 patients. Clinical officer anaesthetists had the highest average fresh gas flow rate of 4.9 l/min while second year registrars had the lowest (3.7 l/min). Level of training and the experience of the anaesthetists were not found to influence the administration of fresh gas flow rates. Use of anaesthetic machines with more gas analysers was associated with lower gas flow rates. Volatile agents' consumption was at least 78% above the recommended amounts, with isoflurane showing a bigger difference than halothane. Obstetric surgery and older age were identified as factors that were associated with lower vaporiser settings while premedication and intraoperative analgesics recorded statistically insignificant higher vaporiser settings. Nitrous oxide casted 5 times more than oxygen and l.5 times more than the volatile agents. Estimated annual costs in KNH for nitrous oxide, volatile agents, and oxygen were Ksh.3, 502,835 (USS 50,041), Ksh.2, 234,057 (USS; 31,915) and Ksh.708, 977 (US$ 10,128) respectively. A 61% monetary saving of Ksh. 3.911.975 (USS 55,885) could be saved if the recommended amounts were used. This study recommended awareness and training sessions for anaesthetists, equipping all theatres with machines capable of low flows and fitted with all gas analysers, and daily leak tests to encourage use of low fresh gas flows