Impact of minimal flow anaesthesia on anaesthetic gas consumption and carbon emission - A prospective observational...

There are increasing concerns about heat-trapping properties (global warming potential) of inhaled anaesthetic agents. We decided to assess the reduction in anaesthetic agent consumption in minimal flow anaesthesia and calculate the carbon footprint impact profile, that is, carbon dioxide equivalent (CO₂e) and cost reduction.

This single-arm observational study with modelling using comparative inferential statistics was conducted on 30 patients scheduled for oncosurgery. Data regarding consumption of inhalational agents were collected from the Draeger Primus anaesthesia workstation for 30 patients maintained with minimal flow (0.5 L/min). These data were compared with values of the same patients if they were given low-flow anaesthesia (1 L/min) calculated using a standard formula. Data analysis was done with Statistical Package for Social Sciences version 20 software. P < 0.05 was considered statistically significant. The CO₂e from use of inhalational agents for our institution was calculated using an Environmental Protection Agency greenhouse gas equivalency calculator. Annual cost analysis was done. CO₂e and cost reduction if minimal flows were used was calculated.

Compared to low flow, consumption of sevoflurane and nitrous oxide decreased by 39.5% (P = 0.001) and 51.3% (P < 0.001), respectively, in minimal flow and CO₂ e would be only 382.625 tonnes annually (50.85% less). There would be an annual cost reduction of Indian Rupee (INR) 11.9 lakhs.

Use of minimal flow is associated with less environmental pollution and a profound difference in overall carbon footprint profile alongside a decrease in total cost of anaesthetic agents.