Anesthesia & Clinical Research
Open Access

Abstract

The Progression of Isoflurane-induced Malignant Hyperthermia and Its Attenuation by Cisatracurium in a Pre-clinical Porcine Model of Heart Transplant

Samar K Lowalekar, Haiyan Cao, Xiu-Gui Lu, Patrick R Treanor, Charles K Allam, Vladimir Birjiniuk, Kay B Leissner and Hemant S Thatte

Background: Even after several years of study, the intra-operative diagnosis of Malignant Hyperthermia (MH) and the approach to anesthesia in MH-susceptible individuals has remained a challenge. In this study we present the pre-operative and intra-operative findings of development and progression of MH in a porcine model that was assigned for heart transplants.

Methods: Female Yorkshire swine were assigned as either donor or recipient and anesthetized with inhalational isoflurane with or without cisatracurium. The inadvertent development of signs indicating MH, including, alterations required in ventilator/bypass machine settings, arterial and venous blood tests, gross- and histo-pathology, were followed through the surgeries that lasted for variable durations between donors and recipients.

Results: Both donors and the recipients were apparently MH-susceptible, and showed systemic intraoperative signs of variable severity, that were greater in longer duration recipient surgeries, and in those in which cisatracurium was not administered. These included features of hypermetabolism such as elevated pCO2 and serum lactate, increased requirements for O2 (FIO2), and multi-organ changes, including pulmonary congestion, features of intestinal pseudo-obstruction, and inflammatory infiltrates in livers and hearts.

Conclusions: The isoflurane-induced MH progressed temporally in severity with the duration of surgery. Use of cisatracurium was directly beneficial in attenuating and/or delaying the progress of MH.