Effects of calcium chloride on grafted internal mammary artery flow after cardiopulmonary bypass

The effect of calcium gluconate administration during cardiopulmonary bypass on hemodynamic variables in infants undergoing open-heart surgery

Background

The incidence of complications after heart surgery is a critical factor in disability, deaths, lengthening hospital stays, and increasing treatment costs. The metabolic balance of certain hormones and electrolytes is necessary for proper cardiac function. In children, various biochemical conditions may cause calcium depletion during heart surgery. The purpose of this study was to determine the effect of calcium gluconate administration during cardiopulmonary bypass on hemodynamic variables and clinical outcomes in infants undergoing open-heart surgery. This study was conducted at Rajaie Cardiovascular Medical and Research Center in 2021 using a controlled randomized clinical trial. A total of 60 patients with open-heart surgery weighing up to 10 kg were included in the study. The first group received an intravenous injection of calcium gluconate 20 min after opening the aortic clamp, and the second group was monitored as a control group. Data collection tools included checklists containing demographics, surgical information, and intensive care unit measures.

Results

The Chi-square test or Fisher's exact test showed that the frequency distribution of gender, blood group, Rhesus factor (RH), and clinical diagnosis in the two groups of intervention and control was not statistically significant (p < 0.05). The mean and standard deviation of Ejection Fraction (EF) changes (before and after) were 13.27 ± 9.16 in the intervention group and 8.31 ± 9.80 in the control group (p = 0.065). The results of two-way repeated measures ANOVA showed that mean systolic blood pressure (p = 0.030), mean diastolic blood pressure (p = 0.021), mean heart rate (p = 0.025), mean arterial pressure (p = 0.020), mean pH (p < 0.001), and mean hemoglobin (p = 0.018) in the intervention, and control groups were statistically significant.

Conclusions

In the present study, unlike systolic pressure, mean diastolic blood pressure decreased, and mean arterial pressure increased significantly. As a result, the slope of changes during the study period was different in the intervention and control groups.

Calcium administration In patients undergoing CardiAc suRgery under cardiopulmonary bypasS (ICARUS trial): Rationale and design of a randomized controlled trial

Introduction

Weaning from cardiopulmonary bypass (CPB) is a critical step of any cardiac surgical procedure and often requires pharmacologic intervention. Calcium ions are pivotal elements for the excitation-contraction coupling process of cardiac myocytes. Thus, calcium administration might be helpful during weaning from CPB.

Methods

We describe a multicenter, placebo-controlled, double blind randomized clinical trial to assess the effect of calcium chloride on the need for inotropic support among adult patients during weaning from CPB. The experimental group (409 patients) will receive 15 mg/kg of calcium chloride. The control group (409 patients) will receive an equivalent volume of 0.9% sodium chloride. Both drugs will be administered intravenously as a bolus at the beginning of weaning from CPB.

Results

The primary outcome will be the need for inotropic support between termination of CPB and completion of surgery. Secondary outcomes will be: duration of inotropic support, vasoactive-inotropic score 30 min after transfer to intensive care unit and on postoperative day 1, plasma alpha-amylase on postoperative day 1, plasma Ca²⁺ concentration immediately before and 10–15 min after calcium chloride administration, non-fatal myocardial infarction, blood loss on postoperative day 1, need for transfusion of red blood cells, signs of myocardial ischemia on electrocardiogram after arrival to intensive care unit, all-cause mortality at 30 days or during hospital stay if this is longer than 30 days.

Discussion

This trial is designed to assess whether intravenous calcium chloride administration could reduce the need for inotropic support after cardiopulmonary bypass weaning among adults undergoing cardiac surgery.

Current Practice of Calcium Use During Cardiopulmonary Bypass Weaning: Results of an International Survey

OBJECTIVES

To describe international practices on the use of calcium salts during cardiopulmonary bypass (CPB) weaning in adult cardiac surgery patients.

DESIGN

Multiple-choice survey on current practice of CPB weaning.

SETTING

Online survey using the SurveyMonkey platform.

PARTICIPANTS

Departments of cardiac anesthesiology worldwide.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Out of 112 surveys sent, 100 centers from 32 countries replied. The majority of centers (88 of 100 = 88%) administer calcium salts intraoperatively: 71 of 100 (71%) are using these drugs for CPB weaning and 78 of 100 (78%) for correction of hypocalcemia. Among the 88 centers that use calcium salts intraoperatively, 66% (58 of 88) of respondents use calcium chloride, 22% (19 of 88) use calcium gluconate, and 12% (11 of 88) use both drugs. Calcium salts are routinely used during normal (47 of 71 centers = 66%) and difficult (59 of 71 centers = 83%) weaning from CPB. Doses of 5 to 15 mg/kg during termination of CPB were used by 55 of 71 centers (77%) either by bolus (39 of 71, 55%) or over a time period longer than 1 minute (32 of 71 = 45%). Norepinephrine is the most commonly used first line vasopressor or inotropic agent used to support hemodynamics during termination of CPB in 32 out of 100 centers (32%), and calcium is the second one, used by 23 out of 100 centers (23%).

CONCLUSION

This survey demonstrates that the majority of cardiac centers use calcium in adult patients undergoing cardiac surgery, especially during weaning from CPB. There is variability on the type of drug, dose, and modality of drug administration.

Calcium Administration During Weaning From Cardiopulmonary Bypass: A Narrative Literature Review

The search for safe and effective patient management strategies during weaning from cardiopulmonary bypass is ongoing; intravenous calcium is occasionally used as a first-line drug. The physiologic role of calcium suggests that it can support the function of the cardiovascular system during this critical period. Patients may be mildly hypocalcemic after cardiopulmonary bypass; however, this degree of hypocalcemia does not significantly impair the cardiovascular system. The transient beneficial effects of calcium administration (increase in arterial blood pressure, systemic vascular resistance, cardiac index, stroke volume, and coronary perfusion pressure) might be helpful in cases of moderate contractility reduction or vasoplegia. Nonetheless, effects on clinically relevant endpoints are unknown, and possible systemic side effects, such as transient reduction in internal mammary artery graft flow, attenuation of the effects of β-sympathomimetics, "stone heart" phenomenon, and pancreatic cellular injury, may limit the use of calcium salts. Further studies are needed to expand the understanding of the effects of calcium administration on patient outcomes.

Intraoperative Acute Multivessel Coronary Vasospasm in Cardiac Allograft: A Case Report

We present a patient who developed acute intraoperative cardiac failure requiring open cardiac message immediately after uncomplicated heart transplantation. After successful resuscitation and establishment of extracorporeal membrane oxygenation, coronary angiography showed diffuse multivessel coronary vasospasm, which responded to intracoronary and IV administration of vasodilators. Cardiac function gradually improved and the patient was discharged home after a prolonged hospital course. Cardiac allograft dysfunction associated with coronary vasospasm immediately after heart transplantation has not previously been reported.

In Vivo and In Vitro Effects of Stellate Ganglion Blockade on Radial and Internal Mammary Arteries

OBJECTIVE

To investigate the effects of stellate ganglion blockade (SGB) on the internal mammary (IMA) and radial arteries (RA) in patients undergoing coronary artery bypass graft (CABG) surgery with in vivo and in vitro studies.

DESIGN

Prospective, randomized trial.

SETTING

University hospital.

PARTICIPANTS

Thirty-seven patients undergoing CABG surgery.

INTERVENTIONS

SGB was performed on 19 patients before anesthesia induction. Another group of 18 patients underwent surgery without SGB. Diameters of proximal RA, distal RA, and IMA were determined by Doppler ultrasonography before (T1) and after (T2) anesthesia induction. Control or blocked IMA and RA segments were obtained. Norepinephrine (NE) was applied to determine the contractile force of IMA and RA rings in a concentration-dependent manner. The maximal contractile response and the sensitivity of the vessels were compared.

MEASUREMENTS AND MAIN RESULTS

The diameters of IMA and distal RA were statistically larger in the SGB group than those in the control group at T2. NE-induced maximum contraction was higher in the blocked RA rings than those in the control RA and blocked IMA rings. The sensitivity of IMA segments to NE was higher than that of RA segments in the SGB group. The control and blocked IMA segments showed similar sensitivity to NE.

CONCLUSION

The present results show that SGB not only increases distal RA and IMA diameters but is also associated with in vitro differences, the mechanism of which remains to be elucidated. Therefore, SGB might be considered as an alternative to topical and systemic vasodilators for reducing vasospasm in patients undergoing CABG.