(164) Intravenous Calcium Chloride for Treatment of Hypotension Following Cardiac Surgery

Introduction: Intravenous (IV) calcium salts are often used to assist in achieving hemodynamic stability in cardiac surgery patients in conjunction with vasopressors and inotropes. Decreasing the use of vasoactive agents by use of IV calcium salts may reduce time on vasopressors and length of stay. The data for IV calcium in patients with hypotension in the setting of cardiac surgery is limited. Small studies have supported improved myocardial performance and blood pressure further prompting the use of these agents for treatment of hypotension following cardiac surgery.

Methods: This study was a single center, retrospective chart review evaluating post cardiac surgery patients admitted to the intensive care unit (ICU) from January 2021 to December 2021. A total of 100 patients were included. Patients were included if 18 years of age or older, had one or more ionized calcium (iCa) levels prior to IV calcium chloride (CaCl) administration, IV CaCl given post cardiac surgery, and refractory hypotension. Pregnant and incarcerated patients were excluded. Patients were divided into two groups: low iCa group and normal iCa group. Low iCa was defined as iCa less than or equal to 1.12 mmol/L and normal iCa was defined as iCa greater than 1.12 mmol/L. The primary outcome evaluated was median duration of vasopressor support. Secondary outcomes included change in vasopressor index score (VIS) at 1, 6, and 24 hours after administration, ICU length of stay, hospital length of stay, red blood cell (RBC) requirements, and incidence of post-operative atrial fibrillation.

Results: There was no statistical difference between the low iCa and normal iCa groups for median duration of vasopressor support (27 vs 26 hours, p = 0.50), median change in VIS at 1,6, and 24 hours, median ICU/hospital length of stay, or post-operative atrial fibrillation. Patients with low iCa had a higher incidence of RBC transfusion compared to the normal iCa group, though not statistically significant (37.2% vs 25.9%, p = 0.24).

Conclusions: No difference in vasopressor support duration was observed between post cardiac surgery patients with low iCa and normal iCa levels after IV CaCl administration. Based on the results of this study, it is unclear if IV CaCl administration after cardiac surgery may assist in hemodynamic support despite iCa levels.