Assistent Professor Baylor College of Medicine Houston, Texas, United States
Abstract: Introduction The purpose of this study is to assess the effect of calcium bolus in response to a hypotensive episode in children with single ventricle physiology with parallel circulation. Methods Single center, retrospective analysis of hemodynamic data after calcium bolus administrations post-surgery. To minimize confounders, we excluded calcium boluses concurrently with normal saline, 5% albumin or epinephrine boluses, blood transfusions, or any change in VIS score. Time intervals were the baseline (-60 to -10 minutes); the hypotensive episode (-10 to 0 minutes); and the response (0 to 60 minutes). The main responses assessed were the peak increase in mean blood pressure, duration of the response, and markers of oximetric effects. Results These analyses included 128 boluses in 63 patients. The cohort is 58% male, 88% White, 8% Black, 4% Other. The median age is 9.0 days (IQR=6.8-36.0 days). The surgical procedures were 43% Norwood, 7% Hybrid and 50% BT shunt. Of the total boluses analyzed, 80% and 40% increased the mBP by at least 5 and 10 mmHg respectively. Approx. 70% and 60% of boluses caused a response lasting at least 10 and 20 minutes respectively. The peak response is associated with gender, CaCl bolus dose, and low sBP or dBP at baseline. The duration of the response is associated with birth weight, surgical procedure, mBP, sBP and dBP. The boluses induced a significant increase in arterial oxygen saturation and an upward trend in pulmonary flow, without increasing renal or cerebral oxygen extraction ratios. Conclusions The current study demonstrates that calcium chloride boluses are an effective rescue medication for hypotensive episodes in children with parallel circulation. These boluses lead to a rapid improvement in mean arterial blood pressure, as well as an increase in pulmonary blood flow as demonstrated by greater blood oxygenation. More importantly, the administration of these boluses does not compromise systemic oxygen delivery in these children, likely due to the enhanced blood oxygenation being greater than any potential decrease in systemic blood flow.
