There are case studies on patients who underwent pulmonary surgery while on VV-ECMO for major airway involvements [5,6,7]. Preoperative anticipation of the need of temporary interruptions of lung ventilation and gas exchange failure due to lung comorbidities were main reasons for elective and prophylactic use of intraoperative VV-ECMO. In our patient, on the contrary, ECMO was operated continuously beforehand, started at the instance of massive lung bleeding, and carried out even during and after two surgeries.
We needed to balance among prevention of impermissible amounts of bleeding, safe operation of ECMO and assurance of gas exchange via both native lung ventilation and ECMO. We chose anticoagulation-free VV-ECMO, afraid of anticoagulant-induced exacerbation of bleeding.
Albeit a variety of ECMO surface materials circumventing the use of systemic anticoagulants have long been under development , no stable techniques have yet been established for long-term anticoagulation-free operation of VV-ECMO. Although the PMEA-coated system we employed is indicated to reduce circuit-related adverse effects such as inflammatory responses and thrombo-coagulopathies, these findings were obtained only by either in vitro studies or short-term uses. In addition, only a few case-based studies reported feasibility of long-term VV-ECMO with low-dose anticoagulant uses [9, 10]. Therefore, we needed to pay considerable attention to coagulation status in the circulation. We monitored blood coagulability solely by serum fibrinogen and APTT accompanied by a careful observation of the status of blood stream in ECMO circuit. After all, fortunately we did not need to exchange the anticoagulation-free circuit for as long as five days. It is, however, undeniable that indiscernible changes occurred in the coagulation-fibrinolysis system which would lead to clotting in the circuit, oxygenator failure, vessel embolism, and hemorrhagic events, as indicated by deep venous thrombosis detected on day 6.
Massive hemoptysis is known to present higher mortality rates with greater amounts of bleeding, reported to be as high as 78% . We, therefore, kept ECMO operated at the minimal setting even when considered unnecessary to secure a transfusion route before bleeding is definitely controlled. Prolonged VV-ECMO in hemorrhagic patients would be a challenge in balancing between thrombotic and bleeding events. Although we adopted an anticoagulation-free operation of ECMO in an attempt to avoid bleeding risk, it would increase the risk of life-threatening thrombo-coagulopathies such as pulmonary artery thromboembolism. Therefore, other choices which have a potential to circumvent both risks concurrently would have to be considered such as intermittent operation of ECMO and use of direct thrombin inhibitors including argatroban .
There are considerations regarding the choice of anesthesia while running ECMO. It may be subject to pharmacokinetic instabilities in intravenous anesthetics produced by changes in circulating blood volume due to intraoperative bleeding and extracorporeal circulation, and drug sequestration by ECMO circuit . We, therefore, employed inhalational anesthesia. However, we might need to keep in mind the possibility of unstable delivery of volatile anesthetics in patients with severely reduced pulmonary area for gas exchange as in this case.
The BAE has been considered a first-line therapy for hemoptysis. It is, however, known to be not necessarily successful because of radiographic visualization of non-communicating arteries, perfusion from collaterals, aberrant bronchial arteries, etc. Moreover, embolization of bronchial to spinal artery collaterals would mislead to a serious consequence [1, 2]. We, therefore, decided not to reinstitute BAE after the failure of the first attempt.
In conclusion, considerable experience and expertise in the management of VV-ECMO would enable safe perioperative management of patients with massive pulmonary bleeding resulting in otherwise non-survivable respiratory failure.