Oxygen toxicity seizures during United States Navy Treatment Table 6: An acceptable risk in monoplace chambers?

Introduction: Hyperbaric oxygen treatment (HBOT) may be complicated by oxygen toxicity seizures, which typically occur with hyperbaric partial pressures of oxygen exceeding 203 kPa (2 atmospheres absolute). All other hyperbaric units in Australia exclusively use a multiplace chamber when treating with United States Navy Treatment Table 6 (USN TT6) due to this perceived risk. The purpose of this study was to determine the safety of a monoplace chamber when treating decompression illness (DCI) with USN TT6. Methods: A retrospective review of the medical records of all patients treated at Fiona Stanley Hospital Hyperbaric Medicine Unit with USN TT6 between November 2014 and June 2020 was undertaken. These data were combined with previous results from studies performed at our hyperbaric unit at Fremantle Hospital from 1989 to 2014, creating a data set covering a 30-year period. Results: One thousand treatments with USN TT6 were performed between 1989 and 2020; 331 in a monoplace chamber and 669 in a multiplace chamber. Four seizures occurred: a rate of 0.59% (1/167) in a multiplace chamber; and none in a monoplace chamber, indicating no statistically significant difference between seizures in a monoplace versus multiplace chamber (P = 0.31). Conclusions: The rate of oxygen toxicity seizures in a monoplace chamber is not significantly higher than for treatment in the multiplace chamber. We conclude that using the monoplace chamber for USN TT6 in selected patients poses an acceptably low seizure risk.

Oxygen toxicity seizure mimics

Introduction: Oxygen toxicity seizures (OTS) are a well-recognised complication of hyperbaric oxygen treatment (HBOT). As such, seizure-like activity during HBOT is usually presumed to be a result of central nervous system oxygen toxicity (CNS-OT). Four cases are reported here where causes other than CNS-OT were determined as being the likely cause of the seizure; causes we have labelled ‘OTS mimics’. Through review of the current literature, and our hyperbaric medicine unit’s experience to date, we aimed to highlight the relevance of these OTS mimics, as the potential for significant morbidity and mortality exists with incorrect diagnoses. Methods: A retrospective review of the medical records of all patients treated at the Fiona Stanley Hospital and Fremantle Hospital hyperbaric medicine units who had a seizure during HBOT between November 1989 and June 2020. These events were reviewed to determine whether causes for seizures other than oxygen toxicity were evident. Results: Four OTS mimics were identified: posterior reversible encephalopathy syndrome, pethidine toxicity, previous subarachnoid haemorrhage with resultant epilepsy, and severe hypoglycaemia. Conclusions: This case series highlights the need for caution when diagnosing an apparent OTS. Multiple conditions may mimic the signs and symptoms of oxygen toxicity. This creates scope for misdiagnosis, with potential for consequent morbidity and mortality. A pragmatic approach is necessary to any patient exhibiting seizure-like activity during HBOT, with suspicion for other underlying pathologies.

HISTORICAL DEVELOPMENT OF THE HYPERBARIC OXYGENATION

Background: Hyperbaric oxygenation (HBO) is a treatment in which a patient breathes near 100% oxygen within a chamber at a pressure greater than one atmosphere absolute (ATA). The development of hyperbaric medicine is continuous and associated with the history of underwater activities, the development of physical laws and physiological mechanisms of breathing. Purpose: The aim of this article is to present the development of hyperbaric oxygenation internationally and nationally. Materials and Methods: We have conducted a literature review of the published works on hyperbaric oxygen therapy (HBOT) during the last 100 years. Our survey includes scientific reports and books in English and Bulgarian. Results: Three main periods of the historical development of HBOT can be defined. In the past, HBO did not have much scientific support but is extensively used in the field of medicine. We observed an increase in scientific interest in HBO during the last two decades both in our country and worldwide. The majority of the reviewed articles contained information about different aspects of HBO as clinical uses, effects, risks. HBOT has been used as a primary and adjuvant treatment for a variety of diseases for nearly 50 years in Bulgaria. The main areas of application and researches of hyperbaric oxygen therapy include diving diseases, intoxications, traumatic injuries, soft tissue infections, diabetic foot, hearing loss, some neurological disorders, etc. Conclusion: Over the past decades, hyperbaric oxygen therapy has grown rapidly worldwide in accordance with evidence-based medicine methods, and future developments to expand the knowledge are perspective.

Emergency Medicine Cases in Underwater and Hyperbaric Environments: The Use of in situ Simulation as a Learning Technique

IntroductionHyperbaric chambers and underwater environments are challenging and at risk of serious accidents. Personnel aiming to assist patients and subjects should be appropriately trained, and several courses have been established all over the world. In healthcare, simulation is an effective learning technique. However, there have been few peer-reviewed articles published in the medical literature describing its use in diving and hyperbaric medicine.MethodsWe implemented the curriculum of the Master’s degree in hyperbaric and diving medicine held at the University of Padova with emergency medicine seminars created by the faculty and validated by external experts. These seminars integrated traditional lectures and eight in situ simulation scenarios.ResultsFor the hyperbaric medicine seminar, simulations were carried out inside a real hyperbaric chamber at the ATIP Hyperbaric Treatment Centre, only using air and reproducing compression noise without pressurization to avoid damages to the manikins. The four scenarios consisted of hyperoxic seizures, pneumothorax, hypoglycemia, and sudden cardiac arrest. Furthermore, we added a hands-on session to instruct participants to prepare an intubated patient undergoing hyperbaric oxygen treatment with a checklist and simulating the patient transfer inside and outside the hyperbaric chamber. The diving medicine seminar was held at the Y-40 The Deep Joy pool in Montegrotto Terme (Italy), also involving SCUBA/breath-hold diving (BHD) instructors to rescue subjects from the water. These diving medicine scenarios consisted of neurologic syndrome (“taravana/samba”) in BHD, drowning of a breath-hold diver, pulmonary barotrauma in BHD, and decompression illness in a SCUBA diver.ConclusionWith this experience, we report the integration of simulation in the curriculum of a teaching course in diving and hyperbaric medicine. Future studies should be performed to investigate learning advantages, concept retention, and satisfaction of participants.

Hyperbaric oxygen for sudden hearing loss: Influence of international guidelines on practice in Australia and New Zealand

Introduction: Idiopathic sudden sensorineural hearing loss (ISSHL) is an otolaryngologic emergency. The Undersea and Hyperbaric Medicine Society (UHMS) revised practice guidelines in 2014 adding ISSHL to approved indications. This study investigated whether the UHMS guidelines influenced referral and practice in Australia and New Zealand. Methods: Retrospective review of 319 patient referrals in two time periods (five years prior to addition of ISSHL to indications (T-PRE) and three years post (T-POST)). Results: Seven of eight participating hyperbaric facilities provided data down to the level of the indication for HBOT for analysis. In T-PRE 136 patients were treated with HBOT for ISSHL, representing between 0% and 18% of the total cases to each facility. In the T-POST period 183 patients were treated for ISSHL, representing from 0.35% to 24.8% of the total patients in each facility. Comparison between the two periods shows the proportion of patients treated with ISSHL among all indications increased from 3.2% to 12.1% (P < 0.0009). One facility accounted for 74% (101/136) of ISSHL patients receiving HBOT in T-PRE and 63% (116/183) in T-POST. ISSHL case load at that facility increased from 18% to 24.8% (P = 0.009) after the UHMS guideline publication. Three of the seven units had a significant increase in referrals after the guideline change. Conclusion: There remains equipoise regarding HBOT in the management of ISSHL. Only three out of seven units had a significant increase in ISSHL patients after the UHMS guidelines publication. Without well controlled RCTs to develop guidelines based on good evidence this is unlikely to change and practice variation will continue.

Seizure during hyperbaric oxygen therapy: experience at a single academic hospital in Korea

Background: Hyperbaric oxygen (HBO2) therapy is a safe and well-tolerated treatment modality. Seizures, one of the most severe central nervous system side effects of HBO2 therapy, can occur. Episodes of seizures during HBO2 therapy have not yet been reported in countries such as Korea, where hyperbaric medicine is still in the developmental stage. Methods: The registry data of all patients treated with HBO2 therapy in a tertiary academic hospital in Korea were prospectively collected, and patients who developed seizures during HBO2 therapy between October 2016 and December 2019 were evaluated. In addition, we reviewed previous studies on occurrence of seizures during HBO2 therapy. Results: During the study period, a total of 10,425 treatments were provided to 1,308 patients. The most frequently treated indication was carbon monoxide (CO) poisoning ABSTRACT (n=547, 41.8%). During the HBO2 therapy sessions (total: 10,425), five seizure episodes occurred (patients with CO poisoning: n=4; patients with arterial gas embolism [AGE]: n=1). The frequency of seizures in patients with CO poisoning (0.148%) and AGE (3.448%) was significantly higher than that in patients with all indications (0.048%) (p=0.001). None of the patients had lasting effects due to the seizures. Conclusion: Our study revealed a similar frequency rate in terms of all indications and CO poisoning, and a slightly higher rate in AGE. Seizures were observed in patients with CO poisoning and AGE. Therefore, if clinicians plan to operate a hyperbaric center in a country like Korea, where there are several patients with acute CO poisoning, they should be prepared to handle seizures that may occur during HBO2 therapy.

Application of Hyperbaric Therapy Following Traumatic Amputation. Case Report

Introduction: The origin of hyperbaric therapy can be traced back to 1662, when the world’s 1stchamber was built and used for this type of treatment. The original precise indications for its use were presented in 1977 by the Executive Committee of the Undersea Medical Society. In 1994, the 1st European Congress on Hyperbaric Medicine was held, clarifying the indications for hyperbaric therapy, the educational requirements and training of staff and equipment for hyperbaric centres. Over the years, the list of indications for hyperbaric chamber treatments has become longer. Aim: The aim of the study was to present the validity of using hyperbaric therapy in a patient after traumatic amputation of the left lower leg. Material and Method: The study was conducted in Hyperbaric Therapy Centre CREATOR in Lodz. An individual case study of a patient with traumatic amputation was used as the method. The report analyses the individual’s interview questionnaire and available medical records. Conclusion: Hyperbaric therapy can be an effective method for treating infections with anaerobic bacteria.