The biochemical consequences of cardiopulmonary bypass surgery in children

The Hemodynamic Effects of Bolus Dose Calcium in Patients Undergoing Pulmonary Artery Reconstruction and Unifocalization Surgery: A Pilot Study

OBJECTIVES

To determine if bolus administration of calcium increases pulmonary artery pressures after unifocalization procedures or pulmonary artery reconstruction surgery.

DESIGN

Retrospective cohort study using Stanford University's data warehouse.

SETTING

A large pediatric heart center within an academic quaternary care facility.

PARTICIPANTS

All patients undergoing pulmonary artery reconstruction or unifocalization procedures identifiable in the data warehouse.

INTERVENTIONS

Data were collected from Stanford University's data repository and formatted and analyzed using RStudio (v 2023.06.1+524).

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the change in pulmonary artery systolic pressure (PASP) after a bolus administration of calcium. Secondary endpoints include changes in pulmonary arterial-to-systemic arterial pressure ratio, mean arterial pressure, right-sided filling pressure, and left atrial pressure. The Friedman test was used to assess differences and the Durbin-Conover rank-sum for pairwise comparisons. A difference in PASP after a bolus dose of calcium was found (Friedman X2 = 13.67, p = 0.003), with a higher PASP 5 minutes after calcium administration compared with 2 minutes before administration (35 mmHg v 33 mmHg, p = 0.01), and a higher PASP 10 minutes after calcium administration compared with2 minutes before administration (35 mmHg v 33 mmHg, p = 0.008).

CONCLUSIONS

Calcium bolus administration led to an increase in pulmonary arterial pressure in patients after pulmonary artery reconstruction or unifocalization surgeries. It may be prudent to avoid bolus administration in this patient population immediately after repair or in patients with right ventricular dysfunction.

Perioperative haemodynamic effects of an intravenous infusion of calcium chloride in children following cardiac surgery

Twelve children received an infusion of 10% calcium chloride 0.1 ml/kg to a maximum dose of 5 ml, infused over 5 min, following open heart surgery. Blood ionized calcium, systemic arterial pH, cardiac index, mean systemic arterial blood pressure and systemic vascular resistance index were measured at baseline and repeated 20 and 40 min following completion of the infusion. There was considerable overlap, with no significant differences in the response to the calcium chloride infusion between children with ionized hypocalcaemia (< 1.1 mmol/l) and those with ionized normocalcaemia when its effect on percentage change in either the haemodynamic or biochemical measurements was assessed (p > 0.2 for all measurements; Mann-Whitney). For this reason they were treated as a single group. Significant changes from baseline were noted in mean systemic arterial pressure (p < 0.02), cardiac index (p < 0.01) and systemic vascular resistance index (p < 0.01) after completion of the calcium chloride infusion when analysed using Friedman's two-way analysis of variance. A significant increase in mean systemic arterial blood pressure occurs after an infusion of 10% calcium chloride as a direct result of an increase in the systemic vascular resistance index with a concomitant decrease in cardiac index.