Use of thrombin-based haemostatic matrix in head and neck reconstructions: a potential risk factor for pulmonary embolism

Two Cases of Cerebral Infarcts Caused by Topical Hemostatic Agent Embolism

ABSTRACT

Resorbable topical hemostatic agents are widely used in surgical procedures to control intraoperative bleeding. There have been multiple reports of complications from use of these agents, including pulmonary vasculature thromboembolism, cerebral venous sinus occlusion, and postoperative inflammatory mass lesions each containing the hemostatic agent. We report 2 cases of inadvertent intra-arterial embolization of hemostatic agent. Both cases followed elective surgical cervical spinal procedures, during which gelatin-based local hemostatic agents were used to control unanticipated bleeding. Postoperatively, both patients exhibited neurologic defects and were found to have infarcts of the brain. At autopsy, vertebrobasilar thromboemboli containing foreign material grossly and microscopically consistent with hemostatic matrix material were found in both cases. These are the first reports of hemostatic agent embolization resulting in cerebral infarcts and leading to death.

Rationalizing post-operative prophylactic anticoagulation in reconstructive head and neck cancer patients: a review

Microsurgical reconstructive head and neck cancer patients are at high risk of venous thromboembolism. The use of anticoagulation can reduce their risk; however, this also increases their bleeding risk. It is not clear whether the benefits of treatment outweigh the risks, and whether a specific post-operative anticoagulation regime is superior. The aim of this review is to evaluate the evidence pertaining to the risks and benefits of post-operative anticoagulation and to provide a rationale for its use in head and neck cancer patients receiving free flaps. The secondary aim was to determine the optimal post-operative anticoagulation regimen. A search was conducted in the PubMed and EMBASE databases identifying studies reporting venous thromboembolism rates in reconstructive head and neck cancer patients undergoing free flaps. These studies were reviewed for their eligibility. Outcomes measured were rates of venous thromboembolism, bleeding-related and microsurgical complications. A total of 306 studies were found from the search with another seven studies identified from citations of key articles. After assessment, nine studies were included. Venous thromboembolism rates ranged from 0.5% to 7% and the rates of bleeding-related complications ranged from 2.4% up to 29%. Anticoagulation appears to lower the risk of venous thromboembolism in this patient group, but also increases the bleeding risk. Risk stratification using the Caprini risk assessment model can help surgeons make decisions. For patients with cancer, low molecular weight heparin appears to be superior to heparin given twice daily but equal to heparin given three times daily and the bleeding risk of each medication appears similar.

Efficacy, safety, and physicochemical properties of a flowable hemostatic agent made from absorbable gelatin sponge via vacuum pressure steam sterilization

An effective and viable hemostatic agent is important for stopping bleeding during surgery. However, it is difficult to achieve hemostasis at uneven or deep bleeding sites using a gelatin sponge. A flowable hemostatic agent has therefore been developed by processing and improving gelatin sponge, to address bleeding under these conditions. In this study, we evaluated the efficacy, safety, and physical and chemical properties of this flowable hemostatic agent in various experiments. We examined its efficacy for stopping bleeding in a rabbit model of liver abrasion in vivo, and compared its efficacy in dynamic coagulation and erythrocyte aggregation tests with gelatin sponge in vitro. We also investigated its safety in rat histocompatibility and acute systemic toxicity tests in mice in vivo, and in hemolysis tests in vitro, to determine if the flowable hemostatic agent induced any pathological reactions or adverse events. In terms of its physical and chemical properties, we analyzed the morphology and chemical bonds of the flowable hemostatic agent by optical and electron microscopy and infrared spectroscopy, and its absorbency and density. The flowable hemostatic agent resulted in a shorter mean bleeding time, less bleeding, greater likelihood of successful hemostasis, and reduced clotting time compared with gelatin sponge. The flowable agent produced some changes in physical morphology, but no pathological changes or undesirable outcomes were detected. This flowable topical hemostatic agent thus provides a safe and more effective hemostatic method than gelatin sponge, and more promising results for intraoperative hemostasis, especially on uneven or deep bleeding surfaces.