The use of hyperbaric oxygen for avascular necrosis of the femoral head and femoral condyle: a single centre's experience over 30 years.

Introduction: Avascular necrosis (AVN) is a rare progressive degenerative disease leading to bone and joint destruction. Patients often require surgical intervention. Femoral AVN is the most common anatomical location. Hyperbaric oxygen treatment (HBOT) has been shown to be effective in AVN. We present data collected from one centre over a 30-year period and compare the results with other published data. Methods: A retrospective chart review of all patients receiving HBOT for AVN at Fremantle and Fiona Stanley Hospitals since 1989 was performed. The primary outcome was radiological appearance using the Steinberg score, with secondary outcomes being subjective improvement, the need for joint replacement surgery and rates of complications. Results: Twenty-one joints in 14 patients (14 femoral heads and seven femoral condyles) were treated with HBOT since 1989. Two patients were excluded. Within the femoral head group, nine of the 14 joints (64%) had stable or improved magnetic resonance imaging (MRI) scans post treatment and at six months (minimum); 10 joints (71%) had good outcomes subjectively, three joints required surgical intervention, and three patients developed mild aural barotrauma. Within the femoral condyle group, all five joints had stable or improved post-treatment MRI scans (four had visible improvement in oedema and/or chondral stability), four joints reported good outcomes subjectively, none of the patients required surgical intervention (follow-up > six months). Conclusions: This single centre retrospective study observed prevention of disease progression in femoral AVN with the use of HBOT, comparable to other published studies. This adds to the body of evidence that HBOT may have a significant role in the treatment of femoral AVN.

Cerebral arterial gas embolism after pre-flight ingestion of hydrogen peroxide.

Cerebral arterial gas embolism (CAGE) is a feared complication of ambient depressurisation and can also be a complication of hydrogen peroxide ingestion. We present an unusual case of CAGE in a 57-year-old woman exposed to both of these risk factors. We describe her subsequent successful treatment with hyperbaric oxygen, despite a 72-hour delay in initial presentation and diagnosis, and discuss the safety of aero-medical transfer following hydrogen peroxide ingestions.

An observation of venous gas emboli in divers and susceptibility to decompression sickness.

INTRODUCTION: Decompression sickness (DCS) results from the formation of bubbles within the tissues and blood in response to a reduction in environmental pressure. Venous gas emboli (VGE) are common after diving and are usually only present in small numbers. Greater VGE numbers are an indication of decompression stress, and can be reliably detected using ultrasound imaging. AIM: To examine the relationship between production of VGE following a routine dive and the risk of DCS. METHODS: A matched population of divers with and without a history of DCS were monitored for the production of VGE at 15-minute intervals using ultrasound, following a 405 kPa air dive in a hyperbaric chamber using the DCIEM air decompression table. VGE production was graded using a validated grading system and the data analysed to compare maximum VGE grade and duration of VGE formation. RESULTS: Eleven divers with a history of DCS were compared with 13 divers with no history of DCS. Divers with a history of DCS demonstrated both a higher maximum grade (P=0.04) and longer duration (P=0.002) of VGE production compared to divers without a history of DCS. CONCLUSION: Higher maximum VGE grades and longer durations of VGE following decompression were associated with a history of DCS and, in particular, musculoskeletal DCS. Although the exact mechanism of DCS remains poorly understood, our data suggest some individuals are inherently more prone to develop VGE, increasing the probability of DCS. Modification of diving practices in those with high VGE grades could potentially decrease DCS risk in these individuals.

A mysterious case of chest pain.

Atrial myxomas can present a diagnostic dilemma attributed to their broad spectrum of clinical presentations. We report the case of a 46-year-old woman in whom the diagnosis of atrial myxoma initially eluded cardiologists despite the large size of her tumour.