Outcomes of Surgical Repair of Vascular Rings and Slings in Children: A Word for the Asymptomatic.

Vascular rings (VRs) are rare aortic arch anomalies that may present with a wide variety of symptoms related to esophageal and/or airway compression. We reviewed our surgical experience in both symptomatic and asymptomatic children. All children (n = 58) who underwent surgical repair of VRs or slings (mean age 27.4 ± 45.60 months; 36 males [62%]) between March 2000 and April 2020 were included. The most common anatomic variant was a right aortic arch (RAA) with aberrant left subclavian artery (ALSCA) (n = 29; 50%). Kommerell's diverticulum was present in 23 of these patients (79%). The second most common variant was a double aortic arch (n = 22; 38%), followed by pulmonary artery sling (n = 4; 6%), RAA with mirror image branching and left ligamentum arteriosum (n = 3; 5.2%), and left aortic arch (LAA) with aberrant right subclavian artery (n = 1; 1.7%). One patient had a double ring with pulmonary artery sling and RAA with ALSCA. Symptoms were present in 42 patients (72%). Left lateral thoracotomy was the approach in 50 patients (86%), while sternotomy was used in 8 (14%). Symptomatic improvement occurred in the majority of symptomatic patients (93%). There was one perioperative mortality (1.7%) in the symptomatic group which was non-VR related. Morbidities included recurrent laryngeal nerve injury in three patients (5.2%) and transient chylothorax in two (3.4%). Persistence/recurrence of symptoms resulted in one early and one late reoperation. The mean follow-up was 3 ± 5 years. In the current era, VR repair in children including asymptomatic ones can be performed with excellent results. We recommend complete repair of RAA with aberrant LSCA by resection of Kommerell's diverticulum and translocation of the ALSCA to avoid recurrence.

Anesthetic management of pediatric patients diagnosed with X-linked adrenoleukodystrophy: A single-center experience.

BACKGROUND: X-linked adrenoleukodystrophy is a progressive demyelinating disease that primarily affects males with an incidence of 1:20 000-30 000. The disease has a wide spectrum of phenotypic expression and may include adrenal insufficiency, cerebral X-linked adrenoleukodystrophy and adrenomyeloneuropathy. The condition has implications for the administration of anesthesia and reports of anesthetic management in those patients are limited at this point. AIM: To review the perioperative care, complications and outcomes of patients diagnosed with X-linked adrenoleukodystrophy at the University of Minnesota Masonic Children's Hospital. METHOD: After obtaining IRB approval, we performed a retrospective chart review of pediatric patients diagnosed with X-linked adrenoleukodystrophy who underwent either surgery or diagnostic/therapeutic procedures that included anesthesia services between January 2014 and December 2016. Data included demographics, American Society of Anesthesiologists classification, preoperative diagnosis, history of hematopoietic stem cell transplant, anesthetic approaches, airway management, medications used, intra- and postoperative complications, and patient disposition. RESULTS: We identified 38 patients who had a total of 166 anesthetic encounters. The majority of patients underwent procedures in the sedation unit (75.9%) and received a total intravenous anesthetic with spontaneous ventilation via a natural airway (86.1%). Preoperative adrenal insufficiency was documented in 87.3% of the encounters. Stress-dose steroids were administered in 70.5% of the performed anesthetics. A variety of anesthetic agents were successfully used including sevoflurane, isoflurane, propofol, midazolam, ketamine, and dexmedetomidine. There were few perioperative complications noted (6.6%) and the majority were of low severity. No anesthesia-related mortality was observed. CONCLUSIONS: With the availability of skilled pediatric anesthesia care, children with X-linked adrenoleukodystrophy can undergo procedures under anesthesia in sedation units and regular operating rooms with low overall anesthesia risk.

HeartMate III as a Bridge to Transplantation in an Adolescent With Failed Fontan Circulation.

HeartMate III is an emerging, small-sized centrifugal ventricular assist device. Its lower pump thrombosis and stroke rates make it favorable for use in pediatrics. We report the use of HeartMate III as a bridge to transplantation in an adolescent with failed Fontan circulation. (Level of Difficulty: Advanced.).

Management and Anesthetic Considerations for Patients With Anomalous Aortic Origin of a Coronary Artery.

The term "coronary artery anomalies" encompasses a large and heterogeneous group of disorders that may affect origin, intrinsic anatomy, course, location, and termination of the coronary arteries. With these different anatomies, presentation, symptoms, and outcomes are heterogeneous as well. While significant efforts are directed toward improving diagnosis and risk-stratification, best evidence-guided practices remain in evolution. Data about anesthetic management of patients with coronary anomalies are lacking as well. This review aims to provide the anesthesiologist with a better understanding of an important subgroup of coronary artery anomalies: anomalous aortic origin of a coronary artery. We will discuss classification, pathophysiology, incidence, evaluation, management, and anesthetic implications of this potentially fatal disease group.

Mechanical hemolysis in pediatric patients associated with rapid transfusion and one-way valve.

BACKGROUND: Four similar transfusion reactions involving infants were reported in less than 1 year. After transfusion of red blood cells (RBCs) via syringe in the operating room, each patient experienced discolored urine, laboratory evidence of hemolysis, and acute kidney injury. Clerical and serologic investigations were unremarkable. Mechanical hemolysis was considered. STUDY DESIGN AND METHODS: Simulated syringe transfusions were performed. Measurements included hematocrit (Hct), free hemoglobin, and visual hemolysis index. Washed and unwashed RBCs were tested with or without a recently introduced one-way valve, using a 24- or 16-gauge intravenous catheter. Constant manual pressure (1.43 ± 0.49 mL/sec) or syringe pump (2 mL/min) was used and a subset was timed. RESULTS: The valve increased hemolysis during manual transfusion using both catheters with washed and unwashed RBCs. With the 24-gauge catheter, the change in Hct was -3.53 ± 0.69% with the valve and 0.22 ± 0.13% without (p < 0.00001). Comparing the individual valves tested, differences in hemolysis were observed (change in Hct, p < 0.0001). During manual transfusion with 24-gauge catheter and unwashed RBCs, the degree of hemolysis was greater when it took longer to transfuse with a valve (change in Hct versus time, r = -0.75, p < 0.0001) compared to a slight increase in hemolysis for samples that took less time to transfuse without a valve (change in Hct versus time, r = 0.58, p = 0.23). CONCLUSIONS: Mechanical hemolysis should be considered when investigating possible hemolytic transfusion reactions, especially with high rates of transfusion and use of a valve. During rapid manual transfusion with the valve, greater resistance was associated with increased hemolysis.

An Observational Study of 3 Different Transfusion Medicine Teaching Methods for Medical Students.

Knowledge deficits of transfusion medicine are prevalent among learners and practicing physicians. In the past, the transfusion medicine community has thoughtfully defined the content of transfusion medicine curriculums through Transfusion Medicine Academic Award Group and The Academy of Clinical Laboratory Physicians and Scientists. The manner in which the curriculum should be delivered has been less carefully examined and defined. We completed an observational study in which we analyzed 3 different teaching techniques: in-person faculty-led simulation curriculum consisting of didactic session and simulation ("Simulation group"); hybrid education with a combination of online materials and short in-person simulation ("Hybrid group"); and online-only education module, which delivered the whole curricular content through a variety of online materials and videos ("Online-only group"). Knowledge acquisition was assessed with a 10-question multiple-choice questionnaire, and satisfaction was assessed by a 9-question online student satisfaction survey. A total of 276second-year medical students participated in the study. There was statistically significant difference between pre- and posttest results and in knowledge gain favoring the Simulation group as compared with the Online-only group (P=.03, P<.0001) and favoring the Simulation group as compared with the Hybrid group (P=.004, P<.0001). The Simulation group and Hybrid group medical students were also more satisfied with the education activity as compared with the Online-only group (P<.0001, P<.001). Our study demonstrated that a faculty-run transfusion medicine simulation curriculum consisting of an in-person didactic session and simulation session for the second-year medical students produced greater immediate knowledge acquisition compared with an online only or a hybrid curriculum. Furthermore, any curriculum that contained in-person teaching by faculty was preferred over the online only education.

Anesthetic Management During Atrial Septostomy in a Conjoined Thoraco-Omphalopagus Twin With Tricuspid Atresia and d-Transposition of the Great Arteries Before Separation: A Case Report.

Conjoined twins are uncommon with reported incidences of 1 in 30,000-200,000 births. They represent a heterogeneous population in regard to location of joint body parts and presence/extent of internal organ fusion. Positioning, airway management, possible presence of cross-circulation, and the fact that 2 patients require anesthesia for each procedure present significant challenges to the anesthesiologist. We report the anesthetic care of a conjoined twin set in which one of the patients presented with tricuspid atresia, d-transposition of the great arteries, and both atrial and ventricular septal defect. A balloon atrial septostomy was performed to allow survival after a separation procedure.

Videolaryngoscopy versus Fiber-optic Intubation through a Supraglottic Airway in Children with a Difficult Airway: An Analysis from the Multicenter Pediatric Difficult Intubation Registry.

BACKGROUND: The success rates and related complications of various techniques for intubation in children with difficult airways remain unknown. The primary aim of this study is to compare the success rates of fiber-optic intubation via supraglottic airway to videolaryngoscopy in children with difficult airways. Our secondary aim is to compare the complication rates of these techniques. METHODS: Observational data were collected from 14 sites after management of difficult pediatric airways. Patient age, intubation technique, success per attempt, use of continuous ventilation, and complications were recorded for each case. First-attempt success and complications were compared in subjects managed with fiber-optic intubation via supraglottic airway and videolaryngoscopy. RESULTS: Fiber-optic intubation via supraglottic airway and videolaryngoscopy had similar first-attempt success rates (67 of 114, 59% vs. 404 of 786, 51%; odds ratio 1.35; 95% CI, 0.91 to 2.00; P = 0.16). In subjects less than 1 yr old, fiber-optic intubation via supraglottic airway was more successful on the first attempt than videolaryngoscopy (19 of 35, 54% vs. 79 of 220, 36%; odds ratio, 2.12; 95% CI, 1.04 to 4.31; P = 0.042). Complication rates were similar in the two groups (20 vs. 13%; P = 0.096). The incidence of hypoxemia was lower when continuous ventilation through the supraglottic airway was used throughout the fiber-optic intubation attempt. CONCLUSIONS: In this nonrandomized study, first-attempt success rates were similar for fiber-optic intubation via supraglottic airway and videolaryngoscopy. Fiber-optic intubation via supraglottic airway is associated with higher first-attempt success than videolaryngoscopy in infants with difficult airways. Continuous ventilation through the supraglottic airway during fiber-optic intubation attempts may lower the incidence of hypoxemia.

Prolonged administration of pyridostigmine impairs neuromuscular function with and without down-regulation of acetylcholine receptors.

BACKGROUND: The acetylcholinesterase inhibitor, pyridostigmine, is prophylactically administered to mitigate the toxic effects of nerve gas poisoning. The authors tested the hypothesis that prolonged pyridostigmine administration can lead to neuromuscular dysfunction and even down-regulation of acetylcholine receptors. METHODS: Pyridostigmine (5 or 25 mg·kg·day) or saline was continuously administered via osmotic pumps to rats, and infused for either 14 or 28 days until the day of neuromuscular assessment (at day 14 or 28), or discontinued 24 h before neuromuscular assessment. Neurotransmission and muscle function were examined by single-twitch, train-of-four stimulation and 100-Hz tetanic stimulation. Sensitivity to atracurium and acetylcholine receptor number (quantitated by I-α-bungarotoxin) provided additional measures of neuromuscular integrity. RESULTS: Specific tetanic tensions (Newton [N]/muscle weight [g]) were significantly (P < 0.05) decreased at 14 (10.3 N/g) and 28 (11.1 N/g) days of 25 mg·kg·day pyridostigmine compared with controls (13.1-13.6 N/g). Decreased effective dose (0.81-1.05 vs. 0.16-0.45 mg/kg; P < 0.05) and decreased plasma concentration (3.02-3.27 vs. 0.45-1.37 µg/ml; P < 0.05) of atracurium for 50% paralysis (controls vs. 25 mg·kg·day pyridostigmine, respectively), irrespective of discontinuation of pyridostigmine, confirmed the pyridostigmine-induced altered neurotransmission. Pyridostigmine (25 mg·kg·day) down-regulated acetylcholine receptors at 28 days. CONCLUSIONS: Prolonged administration of pyridostigmine (25 mg·kg·day) leads to neuromuscular impairment, which can persist even when pyridostigmine is discontinued 24 h before assessment of neuromuscular function. Pyridostigmine has the potential to down-regulate acetylcholine receptors, but induces neuromuscular dysfunction even in the absence of receptor changes.

Transgenic Alzheimer mice have a larger minimum alveolar anesthetic concentration of isoflurane than their nontransgenic littermates.

BACKGROUND: More than 12% of all people older than 65 yr have Alzheimer's disease. Because nothing is known about changes in demand of volatile anesthetics in this disease, we determined minimum alveolar anesthetic concentration (MAC) values of isoflurane in young and aged transgenic mice at risk of developing Alzheimer's disease (heterozygote APP23 mice with the "Swedish double mutation"). To differentiate between unspecific effects of the transgenic model and specific Alzheimer effects, we additionally evaluated MAC values in mice with the same genetic construct but without the Alzheimer's disease-causing Swedish double mutation (heterozygote APP51/16 mice). METHODS: MAC was determined in 60 mice (10 per group): heterozygote APP23 mice and their wild type littermates at the age of 4 and 18 mo, respectively, and heterozygote APP51/16 mice and their wild type littermates at the age of 18 mo. Anesthesia was induced with isoflurane in oxygen/air. The concentration of inhaled isoflurane varied between 1.0 and 2.0 Vol%, and the motor reaction to toeclamping was recorded. Means of the MAC values were compared with an unpaired t-test. RESULTS: The MAC of 18-mo-old heterozygote APP23 mice was 1.67 +/- 0.09, i.e., 9% larger than the MAC of their wild type littermates (1.53 +/- 0.14; P = 0.020). Heterozygote APP51/16 mice had a lower MAC than their wild type littermates (1.32 +/- 0.14 vs 1.48 +/- 0.13; P = 0.037). All wild type groups and young heterozygote APP23 mice had comparable MAC values. CONCLUSIONS: The increased MAC value in aged heterozygote APP23 mice seems to be attributable to changes related to Alzheimer's disease.

Long-term effects of botulinum toxin on neuromuscular function.

BACKGROUND: Recent reports indicate increased incidence of Clostridium botulinum infections, particularly among drug abusers and tissue allograft recipients. Botulinum toxin also has potential application in biochemical warfare. The neurotoxin-induced paralysis often requires mechanical ventilation with and without muscle relaxants. The authors investigated the long-term effects of botulinum toxin on muscle function, expression of nicotinic acetylcholine receptors (nAChRs), and their interaction with muscle relaxant, atracurium. METHODS: Rats (n=30) were injected with varying doses (0.625, 2.5, and 10 U) of botulinum toxin into the tibialis muscle. Control animals (n=9) received an equivalent volume of saline. At 128 days after injection, neuromuscular function, pharmacodynamics of atracurium, and nAChRs were evaluated. RESULTS: Nerve-evoked tensions, including tetanic tension and muscle mass, were decreased on the toxin-injected side in a dose-dependent manner relative to saline-injected controls as well as the contralateral side. Specific muscle tension and specific tetanic muscle tension (tensions/muscle mass) were not reduced. The ED10 of atracurium was reduced, the ED50 was unchanged, and the ED90 was increased in the highest (10-U) dose of toxin group. The atracurium plasma concentration to maintain a steady state 50% paralysis was significantly reduced in the 10-U toxin group. The nAChR concentrations in the tibialis muscle were significantly increased in a dose-dependent manner in all experimental groups. CONCLUSION: Botulinum toxin causes dose-dependent long-term neuromuscular changes. The loss of tension generating capacity is almost exclusively related to muscle atrophy, because the specific tension did not change. The decreased ED10, unaltered ED50, and increased ED90 to atracurium suggest its interactions with different isoforms of receptors having varying sensitivity to atracurium. The absence of fade, despite the persistent botulinum toxin-induced denervation (increased nAChRs), suggests that the up-regulated nAChRs may have compensated for the prejunctional effects of botulinum toxin.

Succinylcholine-induced hyperkalemia in acquired pathologic states: etiologic factors and molecular mechanisms.

Lethal hyperkalemic response to succinylcholine continues to be reported, but the molecular mechanisms for the hyperkalemia have not been completely elucidated. In the normal innervated mature muscle, the acetylcholine receptors (AChRs) are located only in the junctional area. In certain pathologic states, including upper or lower motor denervation, chemical denervation by muscle relaxants, drugs, or toxins, immobilization, infection, direct muscle trauma, muscle tumor, or muscle inflammation, and/or burn injury, there is up-regulation (increase) of AChRs spreading throughout the muscle membrane, with the additional expression of two new isoforms of AChRs. The depolarization of these AChRs that are spread throughout the muscle membrane by succinylcholine and its metabolites leads to potassium efflux from the muscle, leading to hyperkalemia. The nicotinic (neuronal) alpha7 acetylcholine receptors, recently described to be expressed in muscle also, can be depolarized not only by acetylcholine and succinylcholine but also by choline, persistently, and possibly play a critical role in the hyperkalemic response to succinylcholine in patients with up-regulated AChRs.