Protamine use in transcarotid arterial revascularization.

OBJECTIVE: The literature suggests that heparin reversal with protamine in transcarotid arterial revascularization (TCAR) decreases postoperative bleeding complications without an increase in stroke or death. However, the dosing of protamine in TCAR has not yet been evaluated. We aimed to evaluate our experience with intraoperative heparin reversal with protamine. METHODS: This was a single-center, retrospective, observational study that evaluated the heparin and protamine doses used during TCAR. All adult patients who underwent TCAR between 9/1/2019 and 4/2/2021 were included. Demographic data was obtained from the Vascular Quality Initiative and protamine/heparin doses were obtained from a chart review. Multivariate logistic regression models were used to assess the association between the protamine/heparin dose ratio and other variables. RESULTS: Sixty-two patients were included. The average protamine/heparin dose ratio used was 0.96 ± 0.12 mg/U; seven had a ratio less than 0.8 mg/U, and one was greater than 1.2 mg/U. Two patients experienced bleeding complications, which were managed non-operatively. No patient with a protamine/heparin ratio greater than 0.8 mg/U had postoperative bleeding. Postoperative bradycardia was observed in 32.3% of patients and hypotension in 35%, with 19% requiring vasopressors. No relationship was identified between the protamine/heparin ratio and bleeding, bradycardia, or hypotension. No 30-day myocardial infarction, stroke or death occurred. CONCLUSIONS: We identified a near 1:1 ratio of a protamine/heparin dosing regimen for the reversal of heparin during TCAR, with postoperative bleeding complications similar to those reported in the literature. However, patients who received a lower protamine/heparin ratio did not experience bleeding complications. In the era of protamine shortages, a future larger-scale study is needed to evaluate the impact of a lower protamine dose on postoperative complications.

Dose-response of intravenous calcium in the surgical intensive care unit.

Background Hypocalcemia is common in patients admitted to the surgical intensive care unit and is associated with increased morbidity and mortality. Current dosing strategies do not always achieve ionized calcium (iCa) normalization, especially in patients with severe hypocalcemia. Objective The purpose of this study was to explore the association between intravenous (IV) calcium dose and change in ionized calcium. Setting Patients admitted to the surgical intensive care unit with concomitant hypocalcemia at a large academic hospital in the United States. Method This single center, retrospective cohort study evaluated the association between IV calcium dose and subsequent change in ionized calcium level in adult surgical intensive care unit patients with hypocalcemia. The primary outcome of this study was to develop a model exploring the association between IV calcium dose and change in iCa levels. Secondary outcomes included describing the average IV calcium dose required to normalize iCa levels, average time to normalization of iCa levels, and assessing the safety of IV calcium replacement. Main outcome measure Change in iCa. Results One hundred and ninety-four patients met study criteria. In the final model initial iCa level, total calcium dose, the interaction between initial iCa level and total calcium dose, age, and pancreatitis remained. The model (R2 = 0.625) is expressed by the following equation: Change in iCa level = 0.462 - 0.011 × [Ca dose] - 0.0007 × [Age] - 0.259 × [Initial iCa] + 0.076 × [initial iCa × Ca dose] - 0.076 × [Pancreatitis]. Removing two patients that received > 10 grams of total calcium improved the R2 to 0.769. Lastly, a simplified model removing age and pancreatitis found a similar R2 of 0.756. Conclusion We observed that change in iCa level after initial calcium dose depended on the baseline iCa. Our full and simplified model excluding two outliers predicted 76.9% and 75.6% of the variation in iCa response, respectively. If validated in other settings this model could be utilized to provide more accurate calcium dosing.

Patient controlled analgesia: The impact of an 8 versus 10 minute lockout interval in postoperative patients.

The purpose of this study was to compare the level of pain control achieved with 8 versus 10 minute lockout intervals in adult patients who received patient controlled analgesia (PCA) within 24 hours of surgery. There was no difference in pain in the first 72 hours between the 8 minute and 10 minutes group. Additionally, there was no difference in time to first PCA regimen change or a composite outcome of adverse events.