Introduction: The mechanism of injury and recovery of divers with inner ear decompression sickness (IEDCS) is not well understood and there is no consensus regarding management following recompression treatment. Given the rare occurrence, divers are not routinely offered the standard therapies that patients with other acute vestibular disorders may be offered such as vestibular rehabilitation. Methods: This is an observational case series of 13 divers presenting acutely with IEDCS to DDRC Healthcare in Plymouth, UK between July 2021 and January 2024. Vestibular and balance tests were undertaken to aid the treating dive physician in the diagnosis and management of the divers with both hyperbaric oxygen therapy and customised vestibular rehabilitation. Results: Average values for vertical perception, posturography, dynamic gait index and patient-reported outcomes measures improved by discharge and at the three month follow up despite 67% showing an ongoing positive head impulse test or nystagmus in the dark on videonystagmography at follow up. Conclusions: Divers should be warned that despite symptom resolution or minimal residual symptoms post-IEDCS there is a high rate of deficit evident on vestibular testing, and this, alongside investigation for a right to left cardiac shunt, should be a major consideration when considering returning to diving. For the clinician, a stopwatch timed Sharpened Romberg’s test appears to be a reasonable method for monitoring progress of balance stabilisation during the treatment period. Early initiation of vestibular rehabilitation exercises should be considered for all divers with IEDCS.

Introduction: Surface cleaning and hand hygiene within hyperbaric chambers are challenging because of the risk of fire with currently used products containing alcohol or glycerine. This study aimed to investigate if hyperbaric conditions could have inhibitory effects on bacteria present on inert materials. Methods: We deposited Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) on inert materials in an experimental chamber (Comex1200Alu) and compressed the chamber environment with air (253 kPa, 95 minutes) (referred to as indoor). The control was contaminated materials placed outside the chamber (referred to as outdoor). We chose inert materials including plastic, metal, and seat upholstery (imitation leather). We measured bacterial growth and survival and compared the groups using a Student’s t-test. Results: Regardless of the surface types tested, there were no significant differences in bacterial reduction between indoor and outdoor conditions for either E. coli or S. aureus and any of the materials (P > 0.05). Conclusions: We found that pressurised air (253 kPa for 95 minutes) has neither proliferative nor bactericidal action on S. aureus and E. coli colonies deposited on inert surfaces compared to those present outside a hyperbaric chamber in normobaric air conditions.

To develop the diving capacity in the Swedish armed forces the current air decompression tables are under revision. A new decompression table named SWEN21 has been created to have a projected risk level of 1% for decompression sickness (DCS) at the no stop limits. The aim of this study was to evaluate the safety of SWEN21 through the measurement of venous gas emboli (VGE) in a dive series. A total 154 dives were conducted by 47 divers in a hyperbaric wet chamber. As a proxy for DCS risk serial VGE measurements by echocardiography were conducted and graded according to the Eftedal-Brubakk scale. Measurements were done every 15 minutes for approximately 2 hours after each dive. Peak VGE grades for the different dive profiles were used in a Bayesian approach correlating VGE grade and risk of DCS. Symptoms of DCS were continually monitored. The median (interquartile range) peak VGE grade after limb flexion for a majority of the time-depth combinations, and of SWEN21 as a whole, was 3 (3-4) with the exception of two decompression profiles which resulted in a grade of 3.5 (3-4) and 4 (4-4) respectively. The estimated risk of DCS in the Bayesian model varied between 4.7-11.1%. Three dives (2%) resulted in DCS. All symptoms resolved with hyperbaric oxygen treatment. This evaluation of the SWEN21 decompression table, using bubble formation measured with echocardiography, suggests that the risk of DCS may be higher than the projected 1%.

We report the case of a 23-year-old male novice diver who sustained cerebral arterial gas embolism (CAGE) during his open water certification training whilst practising a free ascent as part of the course. He developed immediate but transient neurological symptoms that had resolved on arrival to hospital. Radiological imaging of his chest showed small bilateral pneumothoraces, pneumopericardium and pneumomediastinum. In view of this he was treated with high flow normobaric oxygen rather than recompression, because of the risk of development of tension pneumothorax upon chamber decompression. There was no relapse of his neurological symptoms with this regimen. The utility and safety of free ascent training for recreational divers is discussed, as is whether a pneumothorax should be vented prior to recompression, as well as return to diving following pulmonary barotrauma.

Provision of manual chest compressions in a diving bell using a conventional technique is often impossible, and alternative techniques are poorly evidenced in terms of efficacy and sustainability. The first mechanical cardiopulmonary resuscitation (CPR) device suitable for use in this environment, the NUI Compact Chest Compression Device (NCCD), has recently been designed and manufactured. This study assessed both the efficacy of the device in delivering chest compressions to both prone and seated manikins, and the ability of novice users to apply and operate it. Compression efficacy was assessed using a Resusi Anne QCPR intelligent manikin, and the primary outcome was the proportion of compressions delivered to target depth (50-60 mm). The gold standard was that achieved by expert CPR providers delivering manual CPR; the LUCAS 3 mCPR device was a further comparator. The NCCD delivered 100% of compressions to target depth compared to 98% for the gold standard (interquartile range 1.5%) and 98% for the LUCAS 3 when applied to both supine and seated manikins. The NCCD sometimes became dislodged and had to be reapplied when used with a seated manikin. The NCCD can deliver chest compressions at target rate and depth to both supine and seated manikins with efficacy equivalent to manual CPR and the LUCAS 3. It can become dislodged when applied to a seated manikin; its design has now been altered to prevent this. New users can be trained in use of the NCCD quickly, but practise is required to ensure effective use.

Previous studies have demonstrated the beneficial effects of treadmill exercise (EX) on osteoporosis, and of hyperbaric oxygen (HBO) on osteoblast and osteoclast formation in vitro. We investigated the effects of HBO and the combination of HBO and EX on osteoporosis in ovariectomized rats. Forty 3-month-old female Sprague-Dawley rats were randomly divided into 5 groups (n = 8): a sham control group (Control); an ovariectomy group; an ovariectomy with treadmill exercise treatment group; an ovariectomy with HBO treatment group; and an ovariectomy with HBO treatment combined with treadmill exercise group. The HBO exposures were 203 kPa, 85-90% O₂, 90 min and the exercise regimen was 20 m·min⁻¹, 40 min·day¹, 5° slope. Both treatments were administered once daily, five days a week for 12 weeks until the rats were sacrificed. All three treatments (HBO, exercise, and both combined) significantly promoted the expression of the osteoblast-related gene and oxidative metabolism-related gene (PGC-1α). They also exerted significant inhibitory effects on the osteoclast-related mRNA expression (RANKL) and bone resorption marker CTX-I. Additionally, exercise and the combination exercise-HBO treatment increased serum superoxide dysmutase (SOD) and sclerostin expression. No significant between-group difference was observed. Hyperbaric oxygen, exercise, and the combination ameliorated bone microarchitecture deterioration and ovariectomy-induced bone loss in rats, and these inhibitory effects may be associated with the increased SOD and up-regulated PGC-1α.

Carbon monoxide (CO) poisoning can cause neurological complications such as movement disorders and cognitive impairment through hypoxic brain damage. Although peripheral neuropathy of the lower extremities is a known complication of CO poisoning, hemiplegia is very rare. In our case, a patient who developed left hemiplegia due to acute CO poisoning received early hyperbaric oxygen treatment (HBOT). The patient had left hemiplegia and anisocoria at the beginning of HBOT. Her Glasgow coma score was 8. A total of five sessions of HBOT at 243.2 kPa for 120 minutes were provided. At the end of the 5th session, the patient's hemiplegia and anisocoria were completely resolved. Her Glasgow coma score was 15. After nine months of follow-up, she continues to live independently with no sequelae, including delayed neurological sequelae. Clinicians should be aware that CO poisoning can (rarely) present with hemiplegia.