Remede Systems: Transvenous Pacing of the Phrenic Nerve.

The remede System (ZOLL Medical, Minnetonka, MN; Fig 1), which was approved by the Food and Drug Administration in October of 2017, is a transvenous device that stimulates the phrenic nerve for the treatment of central sleep apnea, which is often associated with heart failure and atrial fibrillation. Given the similarity in implantation procedure to pacemakers and implantable cardioverter/defibrillators, the remede System implantation often occurs in the electrophysiology laboratory. Despite the transvenous nature and close proximity to cardiac structures on radiographic imaging, the remede System does not have any cardiac pacing function/antiarrhythmia therapies, and it is important for an anesthesiologist to be able to recognize and manage such a device if they were to come across one preoperatively.

The Year in Electrophysiology: Selected Highlights From 2022.

This special article is the fifth in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors would like to thank the Editor-in-Chief, Dr Kaplan, the Associate Editor-in-Chief, Dr Augoustides, and the editorial board for the opportunity to author this series, which summarizes the key research papers in the electrophysiology (EP) field relevant to cardiothoracic and vascular anesthesiologists. These articles are shaping perioperative EP procedures and practices, such as pulsed-field ablation, cryoablation for first-line treatment for atrial fibrillation, advancements in conduction system pacing, safety issues related to smartphones and cardiac implantable electronic devices, and alterations in EP workflow as the world emerges from the COVID-19 pandemic. Special emphasis is placed on the implications of these advancements for the anesthetic care of patients undergoing EP procedures.

Aveir Leadless Pacemaker: Novel Technology With New Anesthetic Implications.

The Aveir VR Leadless Pacemaker (Abbott, Chicago, IL) recently was approved by the US Food and Drug Administration, and joined the Micra (Medtronic, Minneapolis, MN) transcatheter pacing system in the realm of nontransvenous cardiovascular implantable devices. The Aveir VR offers design improvements over its predecessor, the Nanostim (St. Jude Medical). There are recommendations for the perioperative management of conventional transvenous pacemakers, but leadless pacemakers add a new layer of consideration. Although there have been prior documented experiences with the Micra device, there are enough differences between the Aveir VR and the Micra that it is important to understand what makes the Aveir VR unique if an anesthesiologist were to come across one preoperatively.

Utilization of an Endobronchial Blocker Through a Double-Lumen Tube as Rescue for Inadequate One-Lung Ventilation.

Failure to provide one-lung ventilation can prohibit minimally invasive thoracic surgeries. Strategies for one-lung ventilation include double-lumen endotracheal tubes or endobronchial blockers, but rarely both. Inability to provide lung isolation after double-lumen endotracheal tube placement requires troubleshooting and sometimes the use of extra equipment. This case describes using a unique Y-shaped endobronchial blocker placed through a left-sided double-lumen endotracheal tube after failure to achieve lung isolation with a double-lumen endotracheal tube alone.

Wild-type and A315T mutant TDP-43 exert differential neurotoxicity in a Drosophila model of ALS.

The RNA-binding protein TDP-43 has been linked to amyotrophic lateral sclerosis (ALS) both as a causative locus and as a marker of pathology. With several missense mutations being identified within TDP-43, efforts have been directed towards generating animal models of ALS in mouse, zebrafish, Drosophila and worms. Previous loss of function and overexpression studies have shown that alterations in TDP-43 dosage recapitulate hallmark features of ALS pathology, including neuronal loss and locomotor dysfunction. Here we report a direct in vivo comparison between wild-type and A315T mutant TDP-43 overexpression in Drosophila neurons. We found that when expressed at comparable levels, wild-type TDP-43 exerts more severe effects on neuromuscular junction architecture, viability and motor neuron loss compared with the A315T allele. A subset of these differences can be compensated by higher levels of A315T expression, indicating a direct correlation between dosage and neurotoxic phenotypes. Interestingly, larval locomotion is the sole parameter that is more affected by the A315T allele than wild-type TDP-43. RNA interference and genetic interaction experiments indicate that TDP-43 overexpression mimics a loss-of-function phenotype and suggest a dominant-negative effect. Furthermore, we show that neuronal apoptosis does not require the cytoplasmic localization of TDP-43 and that its neurotoxicity is modulated by the proteasome, the HSP70 chaperone and the apoptosis pathway. Taken together, our findings provide novel insights into the phenotypic consequences of the A315T TDP-43 missense mutation and suggest that studies of individual mutations are critical for elucidating the molecular mechanisms of ALS and related neurodegenerative disorders.

Tracheal Bronchus and Successful Right-Sided Isolation With a Bronchial Blocker.

The presence of a tracheal bronchus, which is often incidentally discovered, complicates endotracheal intubation and lung isolation during thoracic surgery. Prior reports of successful right-sided lung isolation in the presence of tracheal bronchus required utilization of a double lumen tube. Although right-sided lung isolation was required in our case, due to other patient factors, it was determined that a double lumen tube of a suitable size would be unlikely to be placed safely and successfully. We describe the successful use of a Rüsch EZ-Blocker bronchial blocker in obtaining right-sided isolation in a patient with a difficult airway and tracheal bronchus.

Combined Liver Kidney Transplant in Adult Patient With Alagille Syndrome and Pulmonary Hypertension.

In this article, we describe a case of a 33-year-old female with Alagille syndrome complicated by bilateral branch pulmonary artery stenosis resulting in moderate pulmonary hypertension, end-stage liver disease complicated by portal hypertension, and chronic renal disease who presented for combined liver-kidney transplant. Alagille syndrome is an autosomal dominant disease affecting the liver, heart, and kidneys. Multidisciplinary preoperative evaluation was performed with a team consisting of a congenital heart disease cardiologist, a cardiac anesthesiologist, a nephrologist, and a transplant surgeon. We describe Alagille syndrome and our intraoperative management. To our knowledge, this is the first description of a combined liver-kidney transplant in an adult patient with Alagille syndrome.

Ipsilateral Tibiotalar Joint Osteoarthritis Transferred to the Contralateral Tibiotalar Joint.

Classically, it is thought that pain or disability in one leg can stress the contralateral leg, leading to similar symptoms. The mechanism of action for subsequent dysfunction in the healthy limb is thought to involve compensatory changes that are used as a means to reduce stance phase time on the injured limb. This is believed to increase the forces distributed across the healthy limb, ultimately leading to injury. This belief has been challenged, as supportive literature is sparse. The goal of this study was to determine whether an association between tibiotalar (TT) osteoarthritis (OA) in the right vs left lower extremity exists, and whether injury to one lower extremity leads to degeneration in the contralateral lower extremity. The authors evaluated 704 TT joints to determine the presence of OA. A multiple linear regression was performed using a standard P value cutoff (P<.05) and 95% confidence interval. The absolute value of the difference between right and left TT OA was compared for specimens in each decade of life. Multiple regression analysis revealed a positive correlation between right and left TT OA, after correcting for age, sex, and race. Right TT vs left TT had a slope of 0.489 with a P value approaching 0. Findings indicated the absolute value of the difference between right and left TT OA was not zero, and this difference remains significant throughout life. Based on these findings, OA in one ankle does not appear to lead to accelerated OA in the contralateral ankle. [Orthopedics. 2016; 39(4):e664-e667.].

Calcaneocuboid Joint Arthritis of the Midfoot Precedes Tibiotalar Joint Arthritis.

Surgical models have best shown the relationship between ankle and mid-foot osteoarthritis, although findings regarding the calcaneocuboid joint have varied. To the authors' knowledge, no studies have evaluated the relationship between degenerative changes across the tibiotalar and calcaneocuboid joints. The goal of this study was to determine whether such a relationship exists and which joint degenerates first. A single examiner evaluated 694 tibiotalar and calcaneocuboid joints to determine the presence of osteoarthritis. Multiple linear regression analysis was conducted with a standard P value cutoff (P<.05) and 95% confidence interval. The average incidence of tibiotalar and calcaneocuboid osteoarthritis in specimens older than 40 years was compared with the incidence in those 40 years and younger. A positive correlation between tibiotalar and calcaneocuboid osteoarthritis was noted. African-American subjects were less likely than white subjects to have tibiotalar osteoarthritis. The finding of right and left tibiotalar and calcaneocuboid osteoarthritis in subjects 40 years and younger showed that midfoot arthritis was significantly more common than arthritis of the ankle. The prevalence of calcaneocuboid osteoarthritis remains stable after 40 years of age, and the prevalence of tibiotalar osteoarthritis approaches that of calcaneocuboid osteoarthritis. Calcaneocuboid osteoarthritis precedes tibiotalar osteoarthritis. Altered biomechanics involved in calcaneocuboid osteoarthritis are transferred to the tibiotalar joint, leading to tibiotalar osteoarthritis as the subject ages. Early education, surveillance, physical therapy, shoe adjustment, and orthotics may help to reduce the forces across the midfoot and prevent ankle arthritis in the long term. [Orthopedics. 2016; 39(6):e1112-e1116.].