Abstract
Background: Blood cardioplegia has been widely accepted in clinical cardiac surgery based on
its excellent oxygen delivery and pH buffering capacity. To further conserve blood
during clinical cardiac surgery, we formulated a new crystalloid cardioplegic solution
containing histidine (100 mol/L) as the pH buffering agent. Methods: Sixty patients being applied Histidine Buffered Solution (HBS) (n = 27) or Cold Blood
Cardioplegic solution (CBC) (n = 33), both at 4 °C, were studied prospectively. Pre-
and post-bypass left-ventricular (LV) volume was measured by echocardiography. With
a ventricular pressure catheter, LV pressure-volume loops were constructed to determine
the slope of the end-systolic pressure-volume relationship (Emax) without inotropes.
Results: There were no postoperative deaths in either group. Thirty minutes after reperfusion
Emax was significantly better in the HBS group than in the CBC group (6.0±1.0 mmHg/cm3 vs 3.7±0.8 mmHg/cm3). Cardiac Index was also significantly higher in HBS group than in CBC group with
lower inotropic requirement. Homologous blood transfusion was avoided in 64% of the
patients receiving HBS versus 48% of the patients with CBC. Conclusions: We conclude that the new histidine-buffered cardioplegic solution provides effective
protection with excellent recovery of pump performance in clinical open heart surgery.
Key words
Cold blood cardioplegia - Crystalloid cardioplegic solution - Histidine - Open heart
surgery - Clinical trial
