172 M. DeRenzo: J Extra Corpor Technol 2025, 57, 171--173 Cerebral oximetry was monitored with near-infrared spectroscopy( INVOS NIRS, Medtronic, USA). Anticoagulation was monitored using a Medtronic Hepcon Hemostasis Management System PLUS( Medtronic USA), while blood gas analysis was obtained via a Werfren GEM Premier 5000 system( Instrumentation Laboratory, USA). Autologous blood recovery was achieved with a Cell Saver Ò Elite Ò + with dual reservoirs( Haemonetics, USA).
The cardiopulmonary bypass circuit consisted of the following: Essenz heart-lung bypass system( Liva Nova, USA), and a custom tubing pump pack( Medtronic, USA). A prime volume of 1400 mL of Plasmalyte-A, 10,000 units of heparin, and 100 mL of 25 % albumin. The calculated heparin dose was 38,000 units. Following cannulation for CPB, retrograde autologous priming was performed to reduce the prime to 600 mL. The patient was uneventfully placed on CPB and cooled to a bladder temperature of temperature of 14.5 ° Cusing laminar, non-pulsatile flow with a cardiac index ranging between 2.4--2.6 L / min. Before circulatory arrest and at 30-minute intervals, additional heparin was administered to maintain the ACT levels above 480 s with a heparin concentration above 300 l / kg. Standard protocol for PTE procedures utilizes no cross-clamp or cardioplegia, with arrest being induced by ventricular fibrillation secondary to profound hypothermia. The total bypass time was 492 min, with a total circulatory arrest( CA) time was 109 min. The perfusion strategy for this procedure was closely similar to the method developed by UCSD. SvO 2 of > 90 % was achieved before each circulatory arrest to ensure adequate oxygenation to previously ischemic tissue. A total of five CAs were performed for this case in parallel with the number of clots present and the difficulty of access. The procedure was as follows: the perfusionist discontinued CPB( pump off), clamped the arterial line, drained the patient volume into the venous reservoir, and then clamped the venous line. During CA, the surgeon was notified every 5 min with a 20-minute maximum per arrest. During CA, FiO 2 was maintained at 50 %, a sweep of 250 mL / min, and isoflurane at 0.5 %. During each 10-minute full flow interval, the FiO 2 was set to 100 %, sweep of 4 L / min, and isoflurane at 1 %.
Following the repair of the pulmonary arteries, there was no improvement in pulmonary pressure. This may be attributed to right ventricular dysfunction associated with prior distention and inadequate oxygenation from CTEPH. Following unsuccessful weaning from CPB, V-A ECMO was initiated with a 25 Fr. Medtronic cannula inserted into the right femoral artery and a 22 Fr Opti Site( Edwards, USA) cannula placed in the right internal jugular vein with the following settings: a flow 5 L / min, 4000 rpm, sweep of 5.4 L / min, FiO 2 of 100 %, and SvO 2 56.3 %.
The blood pressure dropped from a MAP of 70 mmHg to 40 mmHg, consequently, the patient was switched to V-VA, with the addition of a 16 Fr Fem-Flex femoral arterial cannula( Edwards, USA) and an 8 Fr DLP Ò cannula( Medtronic, USA) in the left superficial femoral artery. The ECMO settings at this time were: a flow of 5.4 L / min at 4000 rpm, sweep of 6 L / min, FiO 2 of 100 %, and SvO 2 of 56.3 %.
The following day, the patient had a chest washout and closure. Five days postoperatively, the patient was transitioned to V-V ECMO, placed on a ventilator at 60 %, and the sweep was reduced from 6 L / min to 0.5 L / min with flows being weaned down gradually from 5.4 L / min to 4 L / min. On the 6th postoperative day in the ICU, the patient experienced a pulmonary hemorrhage with a 4 L loss, leading to subsequent clamping of the ventilator tube. Seven days postoperatively, the patient’ s blood pressure decreased from 133 / 89 mmHg to 96 / 55 mmHg, prompting an increase in flow to 5 L / min and a sweeping increase to 9 L / min. Subsequent labs revealed an elevated plasma-free hemoglobin level of 170 mg / dL, which alerted the ECMO specialist team to prep for an oxygenator changeout in case of oxygenator failure. Eight days postoperatively, continuous renal replacement therapy( CRRT) was added to the circuit through a manifold, and the patient was actively cooled secondary to fever development. Indications for CRRT included a rising potassium of 4.9 mmol / L, bilirubin of 24 mg / dL, creatinine of 5.2 mg / dL, uric acid of 22 mg / dL, BUN of 117 mg / dL, eGFR of 10 mL / min / 1.73 m 2, andaurea nitrogen of 117 mg / dL. Ten days postoperatively, CRRT was discontinued, and the patient was rewarmed to 37 ° C. Perioperative blood product usage was as follows: RBCs 10 units, FFP 8 units, platelets 7 units, and cryoprecipitate 25 units. Unfortunately, on the 24th postoperative day, the family withdrew care. Institutional review board approval was not required for this case report.
Discussion
Although PTE was the indicated treatment, the associated risk factors contributed to postoperative complications. The patient’ s previous removal from a surgical list for unknown reasons may have been attributed to the complexity and high acuity of the surgical procedure.
Pre-operatively, the patient’ s mean PA pressure was 46 mmHg, while the 3-year mortality rate at 50 mmHg was 90 % [ 2 ]. It is unknown how long the patient had elevated PA pressures.
The PTE was deemed unsuccessful because the PA pressure was unchanged. Transesophageal echocardiogram( TEE) demonstrated poor right ventricular function. Upon collaboration, the surgical team initiated ECMO as a last resort to alleviate the pressure and workload of the PA and RV, respectively. Unfortunately, neither the PTE surgical procedure nor ECMO helped this patient, and after 24 days on ECMO, the family withdrew support. It is also noted that an elevation in plasmafree hemoglobin alone is not sufficient cause to warrant an oxygenator exchange [ 7 ]. This patient may be categorized as part of the 2 % mortality and 2 % pulmonary hemorrhage populations [ 5 ], and this case highlights the importance of patient selection for high-risk procedures.
Conclusion
CTEPH is a serious condition that has only one known curative measure. PTE is an invasive surgical procedure that removes blood clots and fibrous tissue by hand. It takes a very skilled surgeon to perform this operation, and it is only successfully performed in a few centers. The case described highlights a patient with severe pulmonary hypertension at an elevated