Diving and hyperbaric medicine最新文献

Barosinusitis, or sinus barotrauma, is a sinonasal injury and/or inflammation that results when the aerated spaces of the nose and sinuses are exposed to an uncompensated change in ambient pressure. We describe a 19-year-old male diver who presented to our clinic on the fourth day following a breath-hold diving session. During descent on a constant weight monofin dive at the South Cyprus World Championship he began to experience symptoms due to the inability to equalise the pressure, particularly in the Eustachian tubes and middle ear cavities. He felt pain and pressure in the upper left half of his face, left upper molars, and under his left eye at 60 metres, and he continued diving down to 74 metres. At presentation to our clinic, he still had ecchymosis under his right eye and pain in his upper right teeth, half of his face, and ear. He also described tingling in the lower left half of his nose and the left half of his upper lip. He received decongestants, B vitamins, and underwent endoscopic sinus drainage which alleviated his symptoms alleviated over time. The diver reported complete resolution of tingling, numbness, and pain after three months. It should not be forgotten that if appropriate treatment is delayed, permanent changes may occur as a result of long-term compression of the nerve, and therefore patients should be monitored closely.

Introduction: Assessing a diver's fitness to dive enhances diving safety, with medical examiners of diving (MED) being entrusted with this responsibility. However, the effectiveness of MED training in preparing physicians for this task remains underexplored. In the Netherlands, where any physician can pursue MED qualification, challenging cases can be presented to a board of experts.

Methods: This retrospective analysis included all cases presented to a board of experts in the period 2013-2023. Aside from baseline information, cases were coded using the International Classification of Diseases 11th Revision (ICD-11). Additionally, the type of advice given by the board was also recorded.

Results: A total of 291 cases could be included, 62.5% were male divers with a median age of 47 years old (interquartile range 29-55). Circulatory (20.9%), respiratory (16.2%), neurologic (14.4%), psychiatric (9.6%) and endocrine (6.5%) disease comprised more than two-thirds of all presented cases. Problems for the MED included multimorbidity, knowledge of guidelines and interpretation of diagnostic data.

Conclusions: These results could be used to improve MED courses or serve as a topic for continuing medical education for MEDs, however, further research into generalisability is required.

Introduction: The COVID-19 pandemic raised significant concerns about fitness to dive due to potential damage to the pulmonary and cardiovascular systems. Our group previously published guidelines (original and revised) for assessment of these divers. Here, we report a prospective, observational study to evaluate the utility of these guidelines.

Methods: Recreational, commercial, and scientific divers with a history of COVID-19 were consented and enrolled. Subjects were evaluated according to the aforementioned guidelines and followed for any additional complications or diving related injuries.

Results: One-hundred and twelve divers (56 male, 56 female, ages 19-68) were enrolled: 59 commercial, 30 scientific, 20 recreational, two unknown (not documented), one military. Cases were categorised according to two previous guidelines ('original' n = 23 and 'revised' n = 89): category 0 (n = 6), category 0.5 (n = 64), category 1 (n = 38), category 2 (n = 2), category 3 (n = 1), uncategorisable due to persistent symptoms (n = 1). One hundred divers (89.3%) were cleared to return to diving, four (3.6%) were unable to return to diving, four (3.6%) were able to return to diving with restrictions, and four (3.6%) did not complete testing. Regarding diving related complications, one diver had an episode of immersion pulmonary oedema one year later and one diver presented with decompression sickness and tested positive for COVID-19.

Conclusions: Most divers who presented for evaluation were able to return to diving safely. Abnormalities were detected in a small percentage of divers that precluded them from being cleared to dive. Guidelines were easily implemented by a variety of clinicians.

Therapeutic hyperbaric chambers require continuous monitoring and maintenance, including periodic requalification. The primary aim is to verify the suitability for continued safe service. Maintenance is regulated in Europe, and in France requalification is mandatory where a hyperbaric chamber operates above pressures equal to or greater than 4 bar gauge. French requalification requires a hydraulic (hydrostatic) pressure test to determine the absence of deformation and leaks during the test. However, in such cases, it is often necessary to move the chamber if the combined mass of the chamber and water may exceed the allowable floor loading strength. In 2009, an innovative alternative to a hydraulic pressure testing was authorised in France. It consists of carrying out a pneumatic pressure test simultaneously with a non-destructive monitoring technique called 'acoustic emission'. This can be compared to a microseismology technique, where sensors are applied to the pressure retaining boundary of the hyperbaric chamber, and signals emitted by the vessel under load are captured. These signals are analysed, prioritised, and classified, to determine the physical position of any sources (artifacts) through triangulation calculations. This technique makes it possible to assess the behaviour of the vessel very accurately in real time and, a posteriori, to assess its fitness for continued service. This technique reduces the unavailability time of the chamber to two days, compared to potentially several weeks when a hydraulic test is performed. Over and above financial considerations and availability of facilities, this technique provides a baseline of the integrity of pressure vessels and allows monitoring over time of any potential deterioration.

Introduction: We aimed to study middle ear barotrauma caused by fast compression followed by buoyant ascent escape from 200 m underwater and its effect on the auditory system, and to validate the preventive effect of tympanocentesis on middle ear barotrauma.

Methods: Twenty Sprague Dawley rats were divided into two groups: rats in group A underwent a simulated fast buoyant ascent escape from a depth of 200 m, while those in group B underwent tympanocentesis before the procedure described for group A. Ear endoscopy, acoustic conductance, and auditory brainstem response (ABR) tests were conducted before and after the procedure to evaluate the severity of middle ear barotrauma and auditory function in both groups. Additionally, histopathological examination of the middle ear in both groups was conducted to evaluate the severity of middle ear barotrauma by observing submucosal haemorrhage.

Results: None of the ears in either group showed any abnormalities before the experiment. In group A, middle ear barotrauma was universally observed after the simulation procedure. The tympanograms of all ears were initially type A and became type B after the procedure. Further, after the simulation, the hearing thresholds at different frequencies (4, 8, 16, 24, and 32 kHz) assessed by ABR significantly increased compared to those before the procedure. In group B, no middle ear barotrauma was observed, and the hearing threshold at each frequency did not change significantly compared with post-puncturing. After dissecting the middle ear, gross pathological observations were consistent with the above results. Microscopically, blood accumulation and submucosal haemorrhage in the middle ear cavity were observed in group A but not in group B.

Conclusions: Fast buoyant ascent from 200 m underwater can cause middle ear barotrauma, resulting in hearing loss. Tympanic membrane puncture can effectively prevent middle ear barotrauma caused by the rapid buoyant ascent escape procedure.

We report an unusual decompression sickness (DCS) incident in a commercial diving project. Eleven divers completed 91 dives to 23.5-36.2 m with bottom times ranging 23-67 min. The divers were breathing compressed air while immersed. Decompression was planned as surface decompression in a deck decompression chamber breathing oxygen typically for 15-30 min. Due to a technical error the divers breathed air rather than oxygen during the surface decompression procedure. Two divers suffered DCS. Both were recompressed on site with the same error resulting in them breathing compressed air rather than oxygen. One of them experienced a severe relapse with cardiovascular decompensation following recompression treatment. While DCS was expected due to the erroneous decompression procedures, it is noteworthy that only two incidents occurred during 91 dives with surface decompression breathing air instead of oxygen. Accounting for this error, the median omitted decompression time was 17 min (range 0-26 min) according to the Bühlmann ZHL-16C algorithm. These observations suggest that moderate omission of decompression time has a relatively small effect on DCS incidence rate. The other nine divers were interviewed in the weeks following completion of the project. None of them reported symptoms at the time, but five divers reported having experienced minor symptoms compatible with mild DCS during the project which was not reported until later.

Diving accidents result from a variety of causes including human error, inadequate health and fitness, environmental hazards and equipment problems. They usually involve a cascade of events resulting in the diver being injured or deceased. The accuracy and usefulness of a diving accident investigation relies on well-targeted interviews, good field investigation, evidence collection and preservation, and appropriate equipment assessment. In the event of a fatality, a thorough and targeted autopsy is indicated. Investigators should have the appropriate knowledge, training, skills and support systems to perform the required tasks. Relevant investigations include the victim's medical and diving history, the dive circumstances and likely accident scenario, management of the accident including rescue and first aid, equipment inspection and testing and a thorough postmortem examination conducted by a forensic pathologist with an awareness of the special requirements of a diving autopsy and the knowledge to correctly interpret the findings. A chain of events analysis can determine the likely accident scenario, identify shortcomings and inform countermeasures.

Introduction: The effects of methylphenidate, a stimulant often prescribed for the treatment of attention-deficit/hyperactivity disorder (ADHD), on the development of central nervous system oxygen toxicity (COT) have not been experimentally evaluated.

Methods: The records of all pure-oxygen-rebreather divers evaluated at our institution from 1975-2022 were assessed. Cases of COT were defined as a new onset of tinnitus, tunnel vision, myoclonus, headache, nausea, loss of consciousness, or seizures resolving within 15 minutes from breathing normobaric air, and matched 4:1 with similar controls. Any medications issued to the diver in the preceding three months, including methylphenidate, were recorded. In the animal arm of this study, male mice were exposed to increasing doses of methylphenidate orally, with subsequent exposure to hyperbaric O₂ until clinically evident seizures were recorded.

Results: Seventy-five cases of COT were identified in divers, occurring at a median of 80 (range 2-240) minutes after dive initiation at a median depth of 5 m (2-13). Hypercarbia was documented in 11 (14.7%) cases. Prescription of methylphenidate in the preceding three months was not associated with increased risk (OR 0.72, 95% CI 0.16-3.32) of COT. In mice, increasing methylphenidate exposure dose was associated with significantly longer mean COT latency time being 877 s (95% CI 711-1,043) with doses of 0 mg·kg⁻¹; 1,312 s (95% CI 850-1,773) when given 0.75 mg·kg⁻¹; and 1,500 s (95% CI 988-2,012) with 5 mg·kg⁻¹ (F = 4.635, P = 0.014).

Conclusions: Observational human data did not demonstrate an association between methylphenidate and an increased risk of COT. Methylphenidate exposure in mice prolongs COT latency and may have protective effects against COT.

Systemic air embolism is a rare but potentially life-threatening complication of computed tomography (CT)-guided lung biopsy. The largest lung biopsy audits report an incidence rate of approximately 0.061% for systemic air embolism, with a mortality rate of 0.07-0.15%. A prompt diagnosis with high index of suspicion is essential, and hyperbaric oxygen treatment (HBOT) is the definitive management. We report the case of a 44-year-old lady who developed a lateral ST elevation myocardial infarction from coronary artery air embolism following CT-guided lung biopsy for evaluation of a left lung lesion. The biopsy was performed in the right lateral decubitus position, and the patient reported chest pain after coughing during the procedure. The clinician decided to proceed, taking four biopsy samples as no pneumothorax was identified in the intraprocedural CT image. The patient was noted to have hypotension with ongoing chest pain post-procedure. Resuscitative measures were taken to stabilise her haemodynamics, and she was successfully treated with HBOT with total resolution of air embolism. She developed a left sided pneumothorax post-treatment and needed intercostal chest drain insertion. The left lung fully re-expanded, and the patient was discharged home after day two of admission.