Chondronecrosis of the cricoid treated with hyperbaric oxygen therapy: A case series.

We present two cases of cricoid chondronecrosis treated with hyperbaric oxygen (HBO2) therapy. Both patients presented with biphasic stridor and dyspnea several weeks after an intubation event. Tracheostomy was ultimately performed for airway protection, followed by antibiotic treatment and outpatient HBO2 therapy. Both patients were decannulated within six months of presentation and after at least 20 HBO2 therapy sessions. Despite a small sample size, our findings are consistent with data supporting HBO2 therapy's effects on tissue edema, neovascularization, and HBO2 potentiation of antibiotic treatment and leukocyte function. We suggest HBO2 therapy may have accelerated airway decannulation by way of infection resolution as well as the revitalization of upper airway tissues, ultimately renewing the structural integrity of the larynx. When presented with this rare but significant clinical challenge, physicians should be aware of the potential benefits of HBO2 therapy.

Acute Pulmonary Edema After Hyperbaric Oxygen Treatment: A Case Report Written With ChatGPT Assistance.

Acute pulmonary edema is a rare but severe complication of hyperbaric oxygen therapy. While patients with known cardiovascular problems may be able to withstand this therapy, rapid decompensation can still occur. Here, we present a case of a patient with known low ejection fraction and severe mitral regurgitation who developed acute pulmonary edema during the first hyperbaric treatment for a foot ulcer. This case highlights the importance of identifying patients that are high risk, such as those with moderate-to-severe cardiac disease, and pursuing other treatment options to avoid this complication.

Hyperbaric oxygen therapy does not alleviate tourniquet-induced acute ischemia-reperfusion injury in mouse skeletal muscles.

During tourniquet application, blood flow is restricted to a limb to stop excessive limb hemorrhage in a trauma setting and to create a bloodless operating field in the surgical setting. During tourniquet-related ischemia, aerobic respiration stops, and ATP is depleted, and during subsequent reperfusion, there is an increase in reactive oxygen species (ROS) production and other endogenous substances, which leads to acute ischemia-reperfusion (IR) injuries, including tissue necrosis and skeletal muscle contractile dysfunction. Hyperbaric oxygen (HBO) therapy can increase the arterial oxygen tension in the tissues of patients with general hypoxia/anoxia, including carbon monoxide poisoning, circulatory arrest, and cerebral and myocardial ischemia. Here, we studied the protective effects of HBO pretreatment with 100% oxygen at 2.5 ATA against tourniquet/IR injury in mice. After one hour of HBO therapy with 100% oxygen at 2.5 ATA was administered to C57/BL6 mice, a rubber band was placed at the hip joint of the unilateral hindlimb to induce 3 h of ischemia and then released for 48 h of reperfusion. We analyzed gastrocnemius muscle morphology and contractile function and measured the levels of ATP and ROS accumulation in the muscles. HBO pretreatment did not improve tourniquet/IR-injured gastrocnemius muscle morphology and muscle contraction. Tourniquet/IR mice with HBO pretreatment showed no increase in ATP levels in IR tissues, but they did have a decreased amount of ROS accumulation in the muscles, compared to IR mice with no HBO pretreatment. These data suggest that one hour of HBO pretreatment with 100% oxygen at 2.5 ATA increases the antioxidant response to lower ROS accumulation but does not increase ATP levels in IR muscles and improve tourniquet/IR-injured muscle morphology and contractile function.

Selecting the Next Generation of Surgeons: General Surgery Program Directors and Coordinators Perspective on USMLE Changes and Holistic Approach.

INTRODUCTION: The United States Medical Licensing Examination (USMLE) was designed as a universal assessment tool for states to determine physician's medical licensure's candidacy. Recent changes in the USMLE exam have changed the way future surgical residency candidate applications will be reviewed. The survey aimed to assess the effect of changes in USMLE exams-USMLE Step 1 pass/fail, complete dissolution of USMLE clinical skills exam, and the role of holistic review in future surgical residency candidacy selection. METHODS: An anonymous online survey was created and distributed to general surgery program directors and coordinators across the USA. The survey aimed to assess attitudes toward changes to USMLE exams and the potential changes with a holistic review of candidate applications. RESULTS: The response rate was 63.7%. Most program directors and coordinators disagree with changing USMLE Step 1 to a pass/fail scoring system. The majority felt that contacts, the medical school's name, and performance in clinical electives and sub-internships would hold more significance. They also believe that a holistic review of application will decrease socioeconomic discrepancies and promote a more diverse and inclusive resident cohort. CONCLUSION: Step 2 clinical knowledge (CK) will gain more importance in future residency matches because of the change in the scoring system of Step 1. The medical school's name, personal contacts, and clinical performance in rotations will hold more significance.

Carbon monoxide poisoning can act as a stress test to reveal underlying coronary artery disease: case report.

Carbon monoxide (CO) poisoning presents with many different cardiac effects, but one important presentation is its effect as a CO stress test to reveal underlying coronary artery disease (CAD). There are a limited number of publications detailing this phenomenon, but after CO intoxication it is important to suspect CAD in association with mild troponin leak or non-ST segment elevation myocardial infarction (NSTEMI) shown on electrocardiogram (EKG). We recently treated three patients with CO poisoning who had underlying CAD. In the first case a man presented to the emergency department with CO toxicity and an ST segment elevation myocardial infarction (STEMI), resulting in emergent angioplasty and the discovery of severe CAD. The second case involved an individual who presented with CO poisoning with rising troponin levels. An angioplasty discovered a stable 90% occlusion. The third case was a patient with CO poisoning and transient inferior T wave inversion EKG with borderline troponin elevation. Angioplasty showed only 30% occlusion, so the patient's presentation was likely due to direct CO cardiac toxicity. These cases demonstrate the varied presentations that CO poisoning can have on patients with underlying heart disease.

Hyperbaric oxygen for late sequelae of carbon monoxide poisoning enhances neurological recovery: case report.

Neuropsychiatric sequelae have been reported in 15%-45% of survivors of carbon monoxide (CO) poisoning. Hyperbaric oxygen (HBO2) therapy reduces the incidence of cognitive and neurological a dysfunction. The efficacy of providing HBO2 beyond the first one to two days after initial insult is unknown. However, some evidence exists for the benefit of this treatment. We report on treating a patient 14 months after CO injury, who responded with markedly improved neurologic status. A 27-year-old scholar was found comatose due to CO poisoning (carboxyhemoglobin = 31.7%). He received five acute HBO2 treatments. After discharge, he developed chorea, Parkinsonism, dystonia, memory loss, slowed processing speed and verbal fluency, leaving him disabled. After the patient reached a clinical plateau, HBO2 was tried again at 90 minutes at 2.4 ATA plus air breaks. Neuropsychological testing was performed at baseline and after each 20 HBO2 cycles, five of which were performed during the period from 14-22 months after CO exposure. After the first 20 treatments, Parkinsonism and dystonia improved. After 40 sessions, further improvements were seen on mental speed, verbal fluency, and fine motor movements. The outcome following 100 treatments was that the patient regained independence, including the ability to drive and to become gainfully employed. Our case calls into question the concept that HBO2 therapy has no role during the chronic phase of CO brain injury. Randomized clinical trials should be considered to evaluate the therapeutic efficacy of HBO2 in patients with neurological sequelae following CO injury.

Risk of continuous bladder irrigation in the monoplace hyperbaric chamber: a cautionary tale.

We previously published our method of performing continuous bladder irrigation (CBI) in a monoplace hyperbaric chamber [1]. This method entailed the use of an IV pump to infuse saline into the monoplace chamber. The specter of causing iatrogenic rupture of the bladder was raised following such a case, reported herein, of a woman with hemorrhagic radiation cystitis leading to cystectomy. Due to the danger of bladder rupture while providing CBI with a pump, we retract ourpreviously reported method and encourage the use of either a gravity-fed system or delay in hyperbaric oxygen therapy treatment until CBI is no longer necessary.

Hyperbaric oxygen-associated seizure leading to stroke.

Oxygen toxicity seizures are a well-known complication of hyperbaric oxygen treatment (HBOT). Until now, there have not been any reported cases of an acute ischaemic event (stroke) as the result of a HBOT-associated oxygen toxicity seizure. We report an event in which a seizure and stroke occurred together and consider that the stroke may have been caused by seizure-induced demand ischaemia. This challenges the generally held view that oxygen toxicity seizures in the clinical hyperbaric setting are benign. A discussion of the literature on the subject of seizure-induced brain injury is included. Risk factors for cerebrovascular disease should be taken into consideration in determining treatment pressures for HBOT, as reducing pressure reduces seizure risk.

Simulation-based Assessment of the Management of Critical Events by Board-certified Anesthesiologists.

BACKGROUND: We sought to determine whether mannequin-based simulation can reliably characterize how board-certified anesthesiologists manage simulated medical emergencies. Our primary focus was to identify gaps in performance and to establish psychometric properties of the assessment methods. METHODS: A total of 263 consenting board-certified anesthesiologists participating in existing simulation-based maintenance of certification courses at one of eight simulation centers were video recorded performing simulated emergency scenarios. Each participated in two 20-min, standardized, high-fidelity simulated medical crisis scenarios, once each as primary anesthesiologist and first responder. Via a Delphi technique, an independent panel of expert anesthesiologists identified critical performance elements for each scenario. Trained, blinded anesthesiologists rated video recordings using standardized rating tools. Measures included the percentage of critical performance elements observed and holistic (one to nine ordinal scale) ratings of participant's technical and nontechnical performance. Raters also judged whether the performance was at a level expected of a board-certified anesthesiologist. RESULTS: Rater reliability for most measures was good. In 284 simulated emergencies, participants were rated as successfully completing 81% (interquartile range, 75 to 90%) of the critical performance elements. The median rating of both technical and nontechnical holistic performance was five, distributed across the nine-point scale. Approximately one-quarter of participants received low holistic ratings (i.e., three or less). Higher-rated performances were associated with younger age but not with previous simulation experience or other individual characteristics. Calling for help was associated with better individual and team performance. CONCLUSIONS: Standardized simulation-based assessment identified performance gaps informing opportunities for improvement. If a substantial proportion of experienced anesthesiologists struggle with managing medical emergencies, continuing medical education activities should be reevaluated.

Endoscopic Bubble Trouble: Hyperbaric Oxygen Therapy for Cerebral Gas Embolism During Upper Endoscopy.

Gas embolism is a rare but potentially devastating complication of endoscopic procedures. We describe 3 cases of gas embolism which were associated with endoscopic procedures (esophagogastroduodenoscopy and endoscopic retrograde cholangiopancreatography). We treated these at our hyperbaric medicine center with 3 different outcomes: complete resolution, death, and disability. We review the literature regarding this unusual complication of endoscopy and discuss the need for prompt identification and referral for hyperbaric oxygen therapy. Additional adjunctive therapies are also discussed.

Challenges in the Ethical Review of Research Involving Complementary and Integrative Medicine.

Complementary and integrative medicine (CIM) involves using practices outside mainstream Western medicine, often derived from Eastern traditional medicine, and combining those practices with Western medicine. Conducting CIM research that is necessary to determine whether particular interventions are beneficial and safe will involve a set of ethical challenges. Institutional review boards (IRBs), also known as research ethics committees or research ethics boards, are responsible for determining that research studies involving human subjects appropriately address ethical and regulatory concerns inherent to the research. Like other research with human subjects, research involving CIM is subject to ethical review and ongoing oversight by an IRB. IRBs are often challenged by the review of CIM. These challenges include accounting for cultural differences and the interests of competing stakeholders. In this report, we describe these issues that were the focus of a workshop that was part of an international conference held in Seoul, Korea, on April 4, 2015.

Continuous bladder irrigation in the monoplace hyperbaric chamber: Two case reports.

INTRODUCTION: Radiation-induced hemorrhagic cystitis is a serious side effect of radiation therapy. Anemia requiring transfusion can ensue. Treatment methods include bladder irrigation, fulguration, and hyperbaric oxygen (HBO2) therapy. Failure of treatment leads to cystectomy associated with a high risk of severe complications (42%) and mortality (16%). Continuous bladder irrigation (CBI) is often required to prevent further clot formation. HBO2 supports the healing process of radiation cystitis. In patients requiring CBI, the time in HBO2 can help cause clot accumulation and obstruction. We describe a method of providing CBI in a monoplace hyperbaric chamber. MATERIALS AND METHODS: An IV to catheter adapter is used, allowing an IV pump to control CBI flow into the chamber. Drainage is collected in an extra-large (2- to 5-liter) bag. The rate is set so the volume does not exceed the bag's capacity. The bag is placed in a manner that precludes spilling and allows monitoring of outflow. RESULTS: CBI was successfully maintained. Brief cases are presented and issues discussed. SUMMARY/CONCLUSIONS: CBI is easily maintained in a monoplace hyperbaric chamber, with readily available equipment allowing for uninterrupted CBI of hemorrhagic cystitis. HBO2 helps mitigate the potential side effects of other interventions in a previously irradiated area.

Hyperbaric oxygen: a useful adjunct for purpura fulminans: case report and review of the literature.

INTRODUCTION: We report a case of a previously healthy adult with flulike symptoms who precipitously declined due to pneumococcal sepsis complicated by disseminated intravascular coagulation (DIC) and purpura fulminans (PF). After one week of care, including ventilation support and hemodialysis, the patient was stable enough for hyperbaric oxygen (HBO2) in an attempt to salvage his threatened extremities. HBO2 resulted in reduction of ischemic tissue and demarcation of blackened tissue to the distal digits. We feel that much at-risk tissue has been spared by HBO2 as an adjunctive therapy. METHODS: Literature on the use of hyperbaric oxygen for purpura fulminans was reviewed for precipitating issues, time to treatment, protocol, other adjuncts and outcomes. RESULTS: Fifteen papers were identified representing 19 cases of PF treated with HBO2. No controlled studies exist. HBO2 was believed to be of value in most cases; the improvement was associated with timeliness and aggressiveness of initiating HBO2. CONCLUSIONS: PF is a fulminant disorder with high mortality and morbidity. Hyperbaric oxygen appears to be useful for the management of PF complications, imposing minimal side effects or complications. Aggressive therapy should be started as soon as it is safe to transfer the patient to a facility for HBO2 treatments.

Crystal structure of HIV-1 Tat complexed with human P-TEFb.

Regulation of the expression of the human immunodeficiency virus (HIV) genome is accomplished in large part by controlling transcription elongation. The viral protein Tat hijacks the host cell's RNA polymerase II elongation control machinery through interaction with the positive transcription elongation factor, P-TEFb, and directs the factor to promote productive elongation of HIV mRNA. Here we describe the crystal structure of the Tat.P-TEFb complex containing HIV-1 Tat, human Cdk9 (also known as CDK9), and human cyclin T1 (also known as CCNT1). Tat adopts a structure complementary to the surface of P-TEFb and makes extensive contacts, mainly with the cyclin T1 subunit of P-TEFb, but also with the T-loop of the Cdk9 subunit. The structure provides a plausible explanation for the tolerance of Tat to sequence variations at certain sites. Importantly, Tat induces significant conformational changes in P-TEFb. This finding lays a foundation for the design of compounds that would specifically inhibit the Tat.P-TEFb complex and block HIV replication.

A randomized controlled trial of simulation-based teaching versus traditional instruction in medicine: a pilot study among clinical medical students.

OBJECTIVE: To compare simulator-based teaching with traditional instruction among clinical medical students. METHODS: Randomized controlled trial with written pre-post testing. Third-year medical students (n = 38) received either a myocardial infarction (MI) simulation followed by a reactive airways disease (RAD) lecture, or a RAD simulation followed by an MI lecture. RESULTS: Mean pre-post test score improvement was seen across teaching modalities (overall change score [simulation] = 8.8 [95% CI = 2.3-15.3], pretest [62.7]; change score [lecture] = 11.3 [95% CI = 5.7-16.9], pretest [59.7]). However, no significant differences were observed between simulator-based teaching and lecture, in either subject domain. CONCLUSIONS: After a single instructional session for clinical medical students, differences between simulator-based teaching and lecture could not be established by the written test protocols used in this pilot. Future studies should consider the effects of iterative exposure assessed by clinical performance measures across multiple centers.