Intrapulmonary Shunting and Paradoxical Air Embolism in Liver Transplantation: A Case Report.

BACKGROUND A paradoxical air embolism (PAE) occurs when air entering the central venous circulation reaches the systemic circulation, occurring through an intracardiac shunt or intrapulmonary shunting. Patients presenting for liver transplantation often have intrapulmonary shunting due to pulmonary arterial vasodilation, even in the absence of hepatopulmonary syndrome. Here, we present a case of hemodynamic collapse believed to be caused by a PAE, which was diagnosed intraoperatively with transesophageal echocardiography (TEE). CASE REPORT A 60-year-old man who was diagnosed with non-alcoholic steatohepatitis cirrhosis presented for deceased donor orthotopic liver transplantation with utilization of normothermic machine perfusion. Following reperfusion of the liver allograft, TEE detected intrapulmonary shunting resulting in air within the left atrium, left ventricle, and ascending aorta. The patient developed severe biventricular dysfunction with ST-segment changes on electrocardiography monitoring and became acutely hypotensive with significant hepatic congestion 5 min after liver reperfusion. High doses of inotropic and vasopressor support were used as well as inhaled nitric oxide. The patient recovered after 30 min of medical management. The liver transplantation operation was successfully completed and the patient was discharged home on postoperative day 7. CONCLUSIONS Intracardiac air at the time of reperfusion during liver transplantation can originate from the donor allograft and result in PAE in the setting of intrapulmonary shunting. PAE can result in intracoronary air and should be considered in cases of hemodynamic instability in liver transplantation, especially if air is seen within the left atrium, left ventricle, and ascending aorta.

Implementation of a Liver Transplant-Specific TEE Guide to Expand TEE Utilization and Improve Workflow During Orthotopic Liver Transplantation.

OBJECTIVES: Transesophageal echocardiography (TEE) is being increasingly utilized during orthotopic liver transplantation to guide perioperative management. Obstacles of improving TEE utilization include the challenge of becoming familiar with the TEE machine, optimizing TEE images, and translating skills acquired in didactic or simulator center-based training into clinical use. METHODS: In an effort to expand TEE utilization and improve workflow among the liver transplantation (LT) anesthesiologists at our institution, a LT-specific TEE guide was created to serve as a reference and educational tool during LT. A 26-question survey was distributed to all LT anesthesiologists before and 6 months after implementation of the LT-specific TEE guide. RESULTS: All seven LT anesthesiologists completed the survey questions during the study period. No statistically significant difference was detected in participant-reported confidence in optimizing targeted TEE views, performing technical aspects of the exam, navigating the knobs on the TEE machine, or in ability to identify abnormal cardiac pathology during the study period. One participant became basic-TEE certified during the study period. CONCLUSIONS: Implementing a liver transplant-specific TEE guide is a strategy to expand TEE utilization, encourage longitudinal TEE education and reinforce concepts learned from hands-on education sessions; however, we did not detect a difference in participant-reported confidence of performing a TEE exam, ability to identify abnormal cardiac pathology or altering workflow. Further studies with larger sample sizes will be needed to evaluate the effectiveness of a LT-specific TEE guide.

Evaluation of Clinical Factors Associated with Adverse Drug Events in Patients Receiving Sub-Anesthetic Ketamine Infusions.

INTRODUCTION: Sub-anesthetic ketamine is frequently used as an analgesic to reduce perioperative opioid consumption and has also been shown to have antidepressant effects. Side effects of ketamine include dizziness, diplopia, nystagmus, and psychomimetic effects. It is unclear what clinical factors may be associated with ketamine-related adverse drug events (ADEs). METHODS: We performed a retrospective review of 95 patients who received sub-anesthetic ketamine infusions at our institution. Data examined associations between ketamine-related ADEs and various clinical characteristics including chronic pain, depression, or psychiatric disorder, patient physical characteristics, chronic opioid use, perioperative opioid use, dose and duration of ketamine infusions, pain scores, and perioperative medications such as serotonergic agents, central nervous system (CNS) depressants, and analgesics. RESULTS: Overall incidence of ketamine-related ADEs was 29.5% and the incidence of psychomimetic effects was 14.8%. We observed that patients with a history of depression have a lower incidence of ketamine-related ADEs compared to patients without a history of depression (10.3% vs 37.3%; p value = 0.007). CONCLUSION: Patients with depression were found to have a statistically significant reduction in the incidence of ketamine-related ADEs. We found no statistically significant positive associations between ketamine-related ADEs and other clinical factors such as a history of chronic pain, psychiatric disease, patient physical characteristics, perioperative opioid use, dose of ketamine infusion, or co-administration of other CNS depressants.