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.

Development of New Donor-Specific and Human Leukocyte Antigen Antibodies After Transfusion in Adult Lung Transplantation.

OBJECTIVES: The development of new human leukocyte antigens (HLAs) and donor-specific antibodies (DSAs) in patients are associated with worse outcomes following lung transplantation. The authors aimed to examine the relationship between blood product transfusion in the first 72 hours after lung transplantation and the development of HLA antibodies, including DSAs. DESIGN: A retrospective observational study. SETTING: At a single academic tertiary center. PARTICIPANTS: Adult lung transplant recipients who underwent transplantation between September 2014 and June 2019. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 380 patients were included in this study, and 87 (23%) developed de novo donor-specific antibodies in the first year after transplantation. Eighty-five patients (22%) developed new HLA antibodies that were not donor-specific, and 208 patients (55%) did not develop new HLA antibodies in the first year after transplantation. Factors associated with increased HLA and DSA development included donor pulmonary infection, non-infectious indication for transplant, increased recipient body mass index, and a preoperative calculated panel reactive antibody value above 0. Multivariate analysis identified platelet transfusion associated with an increased risk of de novo HLA antibody development compared to the negative group (odds ratio [OR; 95% CI] 1.18 [1.02-1.36]; p = 0.025). Cryoprecipitate transfusion was associated with de novo DSA development compared to the negative group (OR [95% CI] 2.21 [1.32-3.69] for 1 v 0 units; p = 0.002). CONCLUSIONS: Increased perioperative transfusion of platelets and cryoprecipitate are associated with de novo HLA and DSA development, respectively, in lung transplant recipients during the first year after transplantation.

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.

Honey Bees (Apis mellifera) Show a Preference for the Consumption of Ethanol.

BACKGROUND: Alcohol abuse and alcoholism are significant global issues. Honey bees are excellent models for learning and other complex behaviors; furthermore, they share many behavioral responses to ethanol (EtOH) with humans and animal models. We develop a 2-feeder choice assay to determine whether honey bees will self-administer and preferentially consume solutions containing EtOH. METHODS: Gustatory responsiveness to EtOH is determined using the proboscis extension reflex and consumption assays. A 2-feeder choice assay is used to examine preference for the consumption of EtOH. Survival assays assess the metabolic and toxic effects of EtOH consumption. RESULTS: Honey bees find the taste of EtOH to be aversive when in water, but addition of sucrose masks the aversive taste. Even though the taste of EtOH is not appetitive, honey bees preferentially consume sucrose solutions containing 1.25 to 2.5% EtOH in a dose-dependent manner. Based on survival assays, honey bees may not be able to derive caloric value from EtOH, and EtOH concentrations of 2.5% or higher lead to significant increases in mortality. CONCLUSIONS: Honey bees will self-administer EtOH and show a preference for consuming solutions containing EtOH. Bees may not be able to efficiently utilize EtOH as an energy source, but EtOH-dependent increases in mortality complicate separating the effects of caloric value and toxicity.

Nutritional value and taste play different roles in learning and memory in the honey bee (Apis mellifera).

Honey bees will learn to respond to an odor when their antennae are stimulated with sucrose, even if they are not fed during the conditioning phase. However, if they are not fed, the memory of this association is significantly reduced 24 h after conditioning. These results suggest that stimulation of proboscis with sucrose and/or the nutritional quality of the reward plays an important role in establishing a long lasting memory. Three sugars, xylose, sorbitol and mannitol, are used to investigate the relationship among learning, sensory perception and nutritional value. The proboscis extension reflex is used to show that honey bees cannot taste these sugars, whereas mortality data suggest that bees can metabolize all three sugars. Feeding with sorbitol or xylose during olfactory associative conditioning restores robust 24 h memories. However, when given a free choice between consuming sucrose alone or sucrose supplemented with these nutritional sugars, bees did not show a preference for food containing the higher nutritional content. Furthermore, bees did not ingest solutions containing only the tasteless sugar even when it was the only food source. Together, these results suggest that nutritional content and not just sensory information is important for establishing long term memories, but that bees may not be able to assess nutritional content when it is disassociated from taste.