An intracellular-like cardioplegic solution. Its enhancement of myocardial protection

We sought to determine the relative protective effects of an intracellular-like, calcium-bearing, crystalloid solution (ICS) and a calcium-free, extracellular-like solution (ECS). Both solutions were similar in concentrations of potassium ions (25 to 26 mEq/L), in pH (7.7 to 7.8), and in osmolarity (340 to 360 mOsm/L). Normothermia was used to obviate masking the true effects of the solutions with the independent effects of hypothermia. Fifty-seven dogs were placed on cardiopulmonary bypass and had global myocardial ischemia for one hour. Continuous infusions and bolus injections into the aortic root of control solutions (n = 24), ECS (n = 15), and ICS (n = 16) were used. Two-hour postischemic ventricular performance was superior for ICS in comparison with ECS or control solutions regardless of administration mode. The multidose mode gave improved results with control and ECS groups. The use of an ICS yields improved postischemic performance in normothermic dog hearts.