Conversion to Veno-arteriovenous Extracorporeal Membrane Oxygenation for Differential Hypoxia.

Background: Patients who require initial venoarterial extracorporeal membrane oxygenation (VA ECMO) support may need to undergo veno-arteriovenous ECMO (VAV ECMO) conversion. However, there are no definitive criteria for conversion to VAV ECMO. We report 9 cases of VAV ECMO at Gyeongsang National University Changwon Hospital, Gyeongsang National University College of Medicine. Methods: Of 158 patients who received ECMO support between January 2017 and June 2019, 82 were supported by initial VA ECMO. We retrospectively reviewed the medical records of 9 patients (7 men and 2 women; age, 53.1±19.4 years) who had differential hypoxia and required VAV ECMO support. Percutaneous transaortic catheter venting was used to detect the differential hypoxia. Results: Among the 82 patients who received VA ECMO support, 9 (10.9%) had differential hypoxia and required conversion to VAV ECMO support. The mean time from VA ECMO support to VAV ECMO support and the mean duration of the VAV support were 2.1±2.2 days and 1.9±1.5 days, respectively. The average peak inspiratory pressure before and after VAV ECMO application was 23.89±3.95 cmH2O and 20.67±5.72 cmH2O, respectively, decreasing by an average of 3.2±3.5 cmH2O (p=0.040). The PaO2/FiO2 ratio was kept below 100 mm Hg in survivors and non-survivors for 116±65.4 and 250±124.9 minutes, respectively (p=0.016). Six patients underwent extracorporeal cardiopulmonary resuscitation, of whom 4 survived (67%). The overall survival rate of patients who underwent conversion from VA ECMO to VAV ECMO was approximately 56%. Conclusion: Rapid detection of differential hypoxia is required when VA ECMO is applied, and efficient conversion to VAV ECMO may be critical for patient survival.

Additional Extracorporeal Membrane Oxygenation Pump Without an Oxygenator for Transseptal Left Atrial Decompression: A Case Report.

A 63-year-old man developed chest pain and dyspnea. Venoarterial-venous extracorporeal membrane oxygenation (ECMO) was applied to the patient due to failing heart after percutaneous coronary intervention. We used an additional ECMO pump without an oxygenator for transseptal left atrial (LA) decompression and performed a heart transplant. Transseptal LA decompression with venoarterial ECMO is not always effective for severe left ventricular dysfunction. Here, we report a case of the effective use of additional ECMO pump without an oxygenator for transseptal LA decompression through controlling the blood flow rate of the transseptal LA catheter.

Fulminant Giant Cell Myocarditis following Heterologous Vaccination of ChAdOx1 nCoV-19 and Pfizer-BioNTech COVID-19.

A 48-year-old female patient underwent a heart transplantation for acute fulminant myocarditis, following heterologous vaccination with the ChAdOx1 nCoV-19 and Pfizer-BioNTech COVID-19. She had no history of severe acute respiratory syndrome coronavirus-2 infection. She did not exhibit clinical signs or have laboratory findings of concomitant infection before or after vaccination. Heart transplantation was performed because her heart failed to recover with venoarterial extracorporeal oxygenation support. Organ autopsy revealed giant cell myocarditis, possibly related to the vaccines. Clinicians may have to consider the possibility of the development of giant cell myocarditis, especially in patients with rapidly deteriorating cardiac function and myocarditis symptoms after COVID-19 vaccination.

The serial connection of two extracorporeal membrane oxygenators for patient with refractory hypoxemia.

A 34-year-old man developed severe hypoxemia and hypercapnia due to acute respiratory distress during ventilator care after surgery with acute intracranial hemorrhage. Severe hypoxemia had not been corrected even with maximum extracorporeal membrane oxygenation (ECMO) flow and full ventilator settings. We applied a novel technique for the serial connection of two veno-venous ECMO circuits for optimal oxygen delivery and CO2 removal and could wean VV ECMO. The use of serial connection of two VV ECMO circuits may be considered worthwhile when severe hypoxemia or hypercapnia are not improved and the use of protective ventilators is not permitted.