Sodium bicarbonate use and the risk of hypernatremia in thoracic aortic surgical patients with metabolic acidosis following deep hypothermic circulatory arrest.

Objective: Metabolic acidosis after deep hypothermic circulatory arrest (DHCA) for thoracic aortic operations is commonly managed with sodium bicarbonate (NaHCO3). The purpose of this study was to determine the relationships between total NaHCO3 dose and the severity of metabolic acidosis, duration of mechanical ventilation, duration of vasoactive infusions, and Intensive Care Unit (ICU) or hospital length of stay (LOS). Methods: In a single center, retrospective study, 87 consecutive elective thoracic aortic operations utilizing DHCA, were studied. Linear regression analysis was used to test for the relationships between the total NaHCO3 dose administered through postoperative day 2, clinical variables, arterial blood gas values, and short‑term clinical outcomes. Results: Seventy‑five patients (86%) received NaHCO3. Total NaHCO3 dose averaged 136 ± 112 mEq (range: 0.0–535 mEq) per patient. Total NaHCO3 dose correlated with minimum pH (r = 0.41, P < 0.0001), minimum serum bicarbonate (r = −0.40, P < 0.001), maximum serum lactate (r = 0.46, P = 0.007), duration of metabolic acidosis (r = 0.33, P = 0.002), and maximum serum sodium concentrations (r = 0.29, P = 0.007). Postoperative hypernatremia was present in 67% of patients and peaked at 12 h following DHCA. Eight percent of patients had a serum sodium ≥ 150 mEq/L. Total NaHCO3 dose did not correlate with anion gap, serum chloride, not the duration of mechanical ventilator support, vasoactive infusions, ICU or hospital LOS. Conclusion: Routine administration of NaHCO3 was common for the management of metabolic acidosis after DHCA. Total dose of NaHCO3 was a function of the severity and duration of metabolic acidosis. NaHCO3 administration contributed to postoperative hypernatremia that was often severe. The total NaHCO3 dose administered was unrelated to short‑term clinical outcomes.

Clinical Predictors for Mortality in adults Undergoing Thoracic Aortic Surgery Requiring Deep Hypothermic Circulatory Arrest.

This retrospective, observational study was performed on adult patients undergoing thoracic aortic surgery (ATAS) requiring standardized deep hypothermic circulatory arrest (DHCA) with following aims. (1). To determine the mortality rate after ATAS-DHCA (2). To determine univariate predictors for mortality after ATAS-DHCA (3). To determine multivariate predictors for mortality after ATAS-DHCA A total of 144 patients operated during 2000/2001 were included. The mortality rate was 11.1%. Univariate predictors for mortality after ATAS-DHCA were preoperative ejection fraction less than 40%, stroke, packed red blood cell transfusion within first 24 hours, sepsis, mediastinal re-exploration for bleeding within first 24 hours, and renal dysfunction. Multivariate predictors for mortality after ATAS-DHCA were sepsis (odds ratio 21.3:1; confidence interval 3.8-12.1;p=0.001), postoperative stroke (odds ratio 7.4:1; confidence interval 1.9-28.7;p=0.004) and mediastinal re-exploration within first 24 hours (odds ratio 7.7:1; confidence interval 1.3-45.1;p = 0.02) We conclude that mortality after ATAS-DHCA remains high. The identified multivariate predictors merit further hypothesis-driven intervention.

Bleeding and Blood Product Utilization in Adults Undergoing Elective Aortic Root Replacement: The impact of Antifibrinolytic Exposure and Aortic Root Prosthesis.

A retrospective observational study was carried out to test the hypothesis that bleeding and blood component utilization are significantly associated with aortic root replacement (ARR). The aims of the study were as follows. (1) To determine antifibrinolytic exposure (AFE) in ARR; (2) To determine mediastinal drainage within the first 24 hours after ARR; (3) To determine blood component transfusion within the first 24 hours after ARR; (4) To determine whether AFE affects bleeding and blood component transfusion for ARR; and, (5) To determine whether type of aortic root prosthesis affects bleeding and/or blood component transfusion after ARR. All adults undergoing elective ARR from 1996-2001 at the Hospital of the University of Pennsylvania were included in the study. Cohort size was 61. Average age was 49.1 years. AFE was 52%: 23.0% aminocaproic acid, and 29% aprotinin. Mediastinal drainage averaged 384 ml for the first 24 hours. Transfusion in the first 24 hours averaged <1 unit red cells, <1 unit plasma, and <16-pack of platelets. Mediastinal drainage and blood component transfusion were not significantly related to AFE or type of surgical prosthesis. Based on these findings the hypothesis is rejected. The protocol for ARR at our institution is associated with excellent haemostatic outcome, regardless of AFE or type of aortic root prosthesis. Further clinical research in haemostatic outcome after thoracic aortic surgery should be directed at more extensive aortic procedures such as aortic arch repair with deep hypothermic circulatory arrest.