Haemodynamic, metabolic and respiratory changes associated with release of tourniquets under general versus regional anaesthesia a comparative study

ABSTRACT

The purpose of this study was to evaluate and compare haemodynamic, respiratory and metabolic changes that associated with the release of tourniquet in adult patients under general and regional anaesthesia. The study was conducted on 40 patients ASA I or II who required tourniquet application for 1 to 1 1/2 hours for lower limb surgery. Twenty patients received general anaesthesia and were ventilated with a tidal volume of 10 ml kg-1 at 12 breaths/minute. The other 20 patients received regional anaesthesia. [Intrathecal]. At the end of the surgery the tourniquet was deflated and heart rate, blood pressure, and ETCO[2], were observed and recorded. Blood gases, serum potassium, sodium and chloride at pre-inflation and one minute after the deflation of the tourniquet were estimated. Heart rate increased but systolic and diastolic blood pressure decreased in both groups after two minutes of tourniquet deflation. The pH and PaO2of the blood decreased while PaCO2 and ETCO2 increased in both groups at one minute after the deflation of tourniquet. Serum potassium increased significantly after tourniquet release in both group [GA and RA]. It was found that changes in heart rate, blood pressure, pH, PaCO2 and ETCO2 were similar in patients of both groups after tourniquets deflation, but PaO2 decreased and serum potassium increased significantly after tourniquet deflation, the heart rate in RA group did not return to base line even at the end of study period i. e 8 minutes after deflation