A Bridge to Bloodless Surgery: Use of Hemoglobin-Based Oxygen Carrier for Anemia Treatment and Autologous Blood Preservation During Redo Pulmonic Valve Replacement

[Treatment of extreme anemia with polymerized bovine hemoglobin : Case report and review of the literature]

This article reports the case of a 29-year-old female Jehovah's Witness with severe anemia after intrauterine fetal death in the 25th week of gestation, complicated by vaginal bleeding, acute renal failure and hemolysis. Due to her religious beliefs the patient categorically refused blood transfusions. Despite adhering to the recommendations for patient blood management, the hemoglobin (Hb) level gradually decreased to 1.9 g/dl on day 10, when she fainted and had to be sedated and invasively ventilated. Inhalative isoflurane was chosen for sedation because of its potential organ-protective effects and because it provides deep sedation with reduced oxygen requirements, while enabling rapid neurological examination during the sedation windows as well as regular and calm spontaneous breathing. Posthypoxic encephalopathy was demonstrated clinically and electroencephalographically by seizure activity during the sedation windows. Anticonvulsive treatment was started. At a hemoglobin of 1.8 g/dl, she received 2 units of polymerized bovine hemoglobin (Hemopure®, Hemoglogin Oxygen Therapeutics LLC, Souderton, PA, USA), repeated several times on subsequent days because of its short half-life. Considerable methemoglobinemia was noted. After subtracting methemoglobin, the hemoglobin rose by 0.4-0.8 g/dl after each 2 units, initially increasing the oxygen binding capacity of the blood by 33%. After a full neurological recovery and weaning from the ventilator but still on hemodialysis, the patient was transferred to another hospital after 38 days.If allogeneic blood transfusion is not an option, administration of polymerized bovine hemoglobin can temporarily increase the oxygen transport capacity as a last resort treatment. Reduction of oxygen requirements by deep inhaled sedation with isoflurane also seems beneficial and provides advantages.

Impact of Preoperative Platelet Count on Bleeding Risk and Allogeneic Transfusion in Multilevel Spine Surgery

STUDY DESIGN

This was an observational cohort study of patients receiving multilevel thoracic and lumbar spine surgery.

OBJECTIVE

The aim of this study was to identify which patients are at high risk for allogeneic transfusion which may allow for better preoperative planning and employment of specific blood management strategies.

SUMMARY OF BACKGROUND DATA

Multilevel posterior spine surgery is associated with a significant risk for major blood loss, and allogeneic blood transfusion is common in spine surgery.

METHODS

A univariate logistic regression model was used to identify variables that were significantly associated with intraoperative allogeneic transfusion. A multivariate forward stepwise logistic regression model was then used to measure the adjusted association of these variables with intraoperative transfusion.

RESULTS

Multilevel thoracic and lumbar spine surgery was performed in 921 patients. When stratifying patients by preoperative platelet count, patients with pre-operative thrombocytopenia and severe thrombocytopenia had a significantly higher rate of transfusion than those who were not thrombocytopenic. Furthermore, those with severe thrombocytopenia had a higher rate of red blood cells, fresh frozen plasma, and platelet transfusion than those with higher platelet counts. Multivariate logistic regression found that preoperative platelet count was the most significant contributor to transfusion, with a platelet count ≤100 having an adjusted odds ratio (OR) of transfusion of 4.88 (95% confidence interval [CI] 1.58-15.02, P = 0.006). Similarly, a platelet count between 101and 150 also doubled the risk of transfusion with an adjusted OR of 2.02 (95% CI 1.01-4.04, P = 0.047). The American Society of Anesthesiologists classification score increased the OR of transfusion by 2.5 times (OR = 2.52, 95% CI 1.54-4.13), whereas preoperative prothrombin time and age minimally increased the risk.

CONCLUSION

Preoperative thrombocytopenia significantly contributes to intraoperative transfusion in multilevel thoracic lumbar spine surgery. Identifying factors that may increase the risk for transfusion could be of great benefit in better preoperative counseling of patients and in reducing overall cost and postoperative complications by implementing strategies and techniques to reduce blood loss and blood transfusions.

LEVEL OF EVIDENCE

2.