The effects of an insulin-glucose-potassium (IGK) pretreatment on the bupivacaine cardiotoxicity
In this study, the potentially beneficial effects of preoperative treatment with glucose, insulin and potassium in a randomized series of 30 consecutive patients undergoing mitral valve replacement, who were in the third and fourth functional groups of the New York Heart Association scale, were investigated. Fifteen patients received glucose, insulin and potassium, and 15 patients received the same volume of normal saline. The characteristics of the groups did not differ. Papillary muscle-biopsy samples were obtained at the time of surgery and analysed for glycogen, both biochemically and histochemically. The clinical course of all patients was monitored closely during the first 24 hours after surgery. The patients receiving glucose, insulin and potassium had higher glycogen levels (43 +/- 13.54 micromol/g) (P < 0.001). In addition, they required less inotropic pharmacological support (scored by the Gradinac method), had fewer ventricular arrhythmias and exhibited improved haemodynamic indices: cardiac output increased (P < 0.025 to P < 0.005), while systemic vascular resistance decreased (P < 0.001). Pretreatment with glucose, insulin and potassium did not, however, affect the patients' postoperative wedge pressure and mortality. The results of this study suggest that glucose, insulin and potassium pretreatment may be beneficial in unfit patients undergoing mitral valve replacement.