Subclavian Cannulation Strategy

ABSTRACT

Background: For patients with acute respiratory distress requiring veno-venous (VV) extracorporeal membrane oxygenation (ECMO), there are several cannulation strategies that may be used. The typical cannulation strategy for VV ECMO is either femoral-femoral or a femoral-internal jugular due to the advantage of using larger vessels to access and can typically be done at the bedside under ultrasound and x-ray guidance. However, there is concern for limited mobility and an increased risk of infection due to the location of the cannulas. VV ECMO with a dual-lumen cannula placed via the subclavian approach is an effective cannulation strategy. Case Review 38-year-old male with a past medical history of childhood asthma and depression. He was hospitalized for respiratory failure due to COVID-19 and intubated on hospital day 2. Despite heavy sedation, paralytics, and prone positioning, his P/F ratio remained less than 50 with peak pressures in the 40s. The multidisciplinary team decided to proceed with cannulation for VV ECMO on day four of intubation. He was cannulated using a 25 French multistage cannula via the left common femoral vein and a 21 French single-stage return cannula via the right common femoral vein. He underwent a tracheostomy on ECMO day four and was able to tolerate weaning of the ventilator over the next few days. Despite only requiring a sweep gas flow of 0.5L/min on ECMO day six, the patient had worsening oxygenation and was unable to achieve a blood flow of more than 3L/min due to chatter. The chest x-ray (CXR) revealed the drainage cannula was now too high and his PaO2 decreased from 101 to 50 despite the same ventilator settings. The drainage cannula was pulled back 6cm at the bedside and flows were increased from 3L/min to 4 L/min with an increase in the PaO2 to 83. On ECMO day seven, oxygenation remained suboptimal and the CXR demonstrated a worsening pneumomediastinum, so the decision was made to transition the patient to a dual-lumen cannula in order to optimize ECMO flow and allow for more aggressive weaning of the ventilator. By ECMO day 12, he was weaned off sedation, out of bed with physical therapy, tolerating CPAP and able to Facetime with his family. ECMO support was utilized to allow for more aggressive ventilator weaning given the pneumomediastinum and increase rehab and nutrition. On ECMO day 16, he was weaned off sweep while on a T-piece with 20L 60%. He remained off sweep for 24 hours and tolerated physical therapy without requiring additional support. By day 17, he was decannulated at bedside. Discussion: By transitioning the ECMO cannulation strategy to optimize oxygenation, facilitate weaning of mechanical ventilation and allow for increased mobility, patients may be decannulated at a higher functional status than if they continued with the original cannulation strategy. Since 2020, our institution has performed 137 dual-lumen subclavian cannulations for patients on VV ECMO with a survival rate of 63%.