Managing Delirium in a patient with Extracorporeal Membrane Oxygenation (ECMO) machine for bridge to lung transplant: A Case report

ABSTRACT

Background: Due to COVID pandemic, there have been increased needs for ECMO circuits to support patients with respiratory failure1. Unfortunately, due to pharmacokinetics alteration of commonly used sedative and psychotropic medications by the ECMO circuits2,new sedation approaches to manage delirium and agitation is required. We present a case of COVID pneumonia patient on ECMO support, whose delirium symptoms were managed with a novel psychopharmacotherapy protocol. Case Mr. M is a 57-year-old male patient with past medical history of obesity, hypertension, admitted to Stanford Hospital due to COVID pneumonia, complicated by respiratory failure, required to be on Veno-Venous ECMO support with bridge to transplant. He had significant hyperactive delirium with Richmond Agitation-Sedation Scale (RASS) score of +3 and ICDSC score of 7 for most of the days, despite heavy conventional pharmacological sedation. We observe the same problems with most patients placed on the ECMO system, leading to an investigation and development of a new protocol. Discussion: Patient on ECMO support requires adequate sedation to prevent clinical deterioration that can result from hyperactive delirium (ie., chugging, blood clots or decannulation)2. Nevertheless, ECMO circuit’s significant alterations of drug pharmacokinetics, such as increased volume of distribution and sequestration of lipophilic and protein bound medications, with no clear guidelines on managing sedation/delirium in patients with ECMO support at this time2, we conducted an extensive literature search and developed a novel protocol. This new sedation approach includes alpha-2 agonists, opioids, barbiturates and calcium channel modulators with the lowest lipophilicity and protein binding potential of each medication in its class4,5,thus overcoming the challenges introduced by ECMO circuits. The new protocol allowed the patient to participate in lung transplant work-up, physical therapy, and eventually facilitated receiving bilateral lung transplantation. Conclusion/Implications ECMO is a life saving device that can help patient with cardiac-respiratory failure, and its use has been increasing in clinical practice. However, there needs to be an improvement in successful sedation/delirium management to minimize adverse events, and optimize the success of this lifesaving technologies. References 1. Cho HJ, et al. ECMO use in COVID-19 lessons from past respiratory virus outbreaks-a narrative review. Crit Care. 2020 Jun 6;24(1)301 2. deBacker J, et al. Sedation Practice in Extracorporeal Membrane Oxygenation-Treated Patients with Acute Respiratory Distress Syndrome A Retrospective Study. ASAIO J. 2018 Jul/Aug;64(4)544-551 3. Lemaitre F, et al. Propofol, midazolam, vancomycin and cyclosporine therapeutic drug monitoring in extracorporeal membrane oxygenation circuits primed with whole human blood. Crit Care. 2015;19(1)40 4. Hansch C, et al. Hydrophobicity and central nervous system agents on the principle of minimal hydrophobicity in drug design. J Pharm Sci. 1987 Sep;76(9)663-87 5. Bockbrader HN, et al. A comparison of the pharmacokinetics and pharmacodynamics of pregabalin and gabapentin. Clin Pharmacokinet. 2010 Oct;49(10)661-9