Use of Extracorporeal Membrane Oxygenation in Blunt Traumatic Injury Patients with Acute Respiratory Distress Syndrome

Background Venovenous extracorporeal membrane oxygenation (VV ECMO) is commonly used to support patients with severe respiratory failure with adequate cardiac function by providing gas exchange while allowing for lung-protection, lung ventilation or pulmonary rest. In the setting of trauma, pulmonary contusion, aspiration, and pulmonary embolism can commonly impair pulmonary function. This (ECMO) can provide a temporary measure of support while awaiting pulmonary recovery. Venoarterial (VA) ECMO is often used to support patients with cardiopulmonary failure who require hemodynamic support such as myocarditis, blunt cardiac injury, large pulmonary embolus, and cardiac ischemia. Extracorporeal membrane oxygenation use may lead to various complications primarily related to bleeding or thromboembolism, as well as infections. Blunt traumatic injury is often associated with pulmonary contusions which can lead to acute respiratory distress syndrome (ARDS) in 6–25% of blunt trauma patients.1,2 Some cases of ARDS may require cardiopulmonary support in the form of ECMO.3 We describe here a series of trauma patients requiring ECMO support and their hospital outcomes between years 2016 and 2019 from a single level 1 trauma hospital that provides ECMO support to ~50 patients/y (60% VV ECMO). Case Series A total of seven patients (all male, aged 32.1 ± 8.7 years) had pulmonary contusions following blunt traumatic injury (six had motor vehicle accident and one had crush injury) causing ARDS and requiring ECMO support. Of the seven patients, five (71%) received VV ECMO and two (29%) received VA ECMO. The VV ECMO was either femoral-jugular or femoral-femoral, both the VA ECMO were femoral-femoral. The mean ECMO support duration was 13.2 ± 6.5 days (median 17 days) and six patients were successfully weaned. Overall, two (29%) patients died before discharge or transfer (one before and one after weaning off ECMO), both of whom had required VA ECMO (Table 1). Table 1. - Demographic, Anticoagulation, and ECMO Support Information Patient Age (y)/Sex Mechanism of Trauma Support Type ECMO Initiated (Days After Injury) ECMO Support (d) Heparin Status Hospital Survival 24/M Fall w/ TBI VV ECMO 9 17 Never started Yes 40/M MVA VV ECMO 20 18 Continued Yes 19/M Blunt chest injury VV ECMO 5 17 Continued Yes 35/M MVA VV ECMO 11 20 Resistance Yes 27/M Crush injury VA ECMO 0 16 Started and withheld No 40/M MVA VV ECMO 8 6 Started and withheld Yes 40/M MVA/PE VA ECMO 22 3 Started and withheld No ECMO, extracorporeal membrane oxygenation; MVA, motor vehicle accident; PE, pulmonary embolism; TBI, traumatic brain injury; VA, venoarterial; VV, venovenous. Anticoagulation Per institutional protocol, all the ECMO patients receive heparin with adjustment based on their coagulation profile and ensuing complications. Patients with contraindication to heparin are given alternative anticoagulation. We followed the protocol on all the seven patients; however, there were several adjustments and exceptions made due to individual profiles particularly due to preceding trauma and resultant bleeding. We have outlined the individual anticoagulation as following. One VV ECMO patient had major intracranial and tracheal bleeding concerns and was placed on ECMO without any anticoagulation therapy. Three VV ECMO patients were given heparin throughout their course of therapy with the exception of 2 days when one required reoperation for a mediastinal hematoma (heparin was restarted postoperatively), one patient on VV ECMO developed heparin resistance as defined by low activated partial thromboplastin time (aPTT) despite increasing dose of heparin and was switched to argatroban without complication, and the other developed thrombocytopenia and was decannulated. One VV ECMO patient and both the VA ECMO patients had either bleeding or ECMO circuit issues that required discontinuation of the anticoagulation therapy and maintained on ECMO without any anticoagulation. None of these three patients had thrombotic events associated with discontinuation of anticoagulation, nor did the patient who was not initiated on anticoagulation due to his intracranial and tracheal bleeding. Patients were not discharged home without anticoagulation regimens and received deep vein thrombosis prophylaxis when appropriate following ECMO decannulation per normal trauma protocol. Complications Four of the five VV ECMO patients had pulmonary infections, which were treated with antibiotics and did not cause additional concerns. One of the VV ECMO patients had developed shock liver and required multiple exploratory laparotomies due to bowel ischemia, ultimately requiring continuous renal replacement therapy (CRRT); however, he was eventually weaned from ECMO and discharged from the hospital. Both of the VA ECMO patients and two of the VV ECMO patients had developed acute renal failure (n = 4), of which three required hemodialysis. One of the VA ECMO patient also had liver injury due to trauma and developed multiple complications post-ECMO, including renal failure requiring CRRT, hypofibrinogenemia, thrombocytopenia, continued blood loss, hip disarticulation, limb ischemia and rhabdomyolysis. Although he was eventually weaned off ECMO, he succumbed to his multiple trauma injuries and died postweaning off ECMO. The other VA ECMO patient had a massive pulmonary embolus, as well as a stroke and anoxic brain injury which were recognized after initiation of the ECMO and did not survive beyond 3 days of support. Conclusion This study has demonstrated a survival benefit with ECMO support in cases of ARDS caused by blunt traumatic lung injury. Due to the multiple injuries and concern for bleeding, anticoagulation management could be challenging in these situations and has to be closely monitored and altered as needed. Although our goal was to anticoagulate all of the patients with heparin, some patients are able to be supported on ECMO without anticoagulation; however, individual clinical scenarios may determine its necessity with regards to risk and benefit. Acute respiratory distress syndrome has a high mortality among trauma patients.4 Despite the utility in treating severe ARDS and other pulmonary disease processes, ECMO has not been universally embraced by the trauma community. Trauma patients with pulmonary contusion and ARDS can be successfully supported by ECMO and have acceptable hospital survival. There are an increasing number of studies that suggest that ECMO is a safe and viable organ support option for trauma patients with ARDS.5–8 Patients requiring VA ECMO support maybe at increased risk of adverse outcomes. Extracorporeal membrane oxygenation may serve as an additional support modality in adult patients with severe traumatic lung injury or acute respiratory failure and ARDS with refractory hypoxemia.