[What is the Best Therapeutic Strategy for Decompression Illness? First Aid Oxygen Inhalation and Hyperbaric Oxygen Therapy].

Decompression illness (DCI), a syndrome following inadequate reduction in environmental pressure, has two forms: decompression sickness and arterial gas embolism after pulmonary barotrauma. Recompression therapy using oxygen, a kind of hyperbaric oxygen therapy, has been considered the gold standard treatment for DCI, although there is no randomized controlled trial evidence for its use. We evaluated the effectiveness of recompression therapy in treating DCI by reviewing the reported therapeutic results of serious DCI, especially neurological disorders. Early or ultra-early recompression therapy did not dramatically improve clinical recovery from DCI symptoms, including spinal cord disorders. In contrast, early first aid normobaric oxygen inhalation highly improved or stabilized clinical conditions of DCI. Based on these clinical results, the international committee for hyperbaric and diving medicine has stated that cases of mild DCI may be managed without recompression therapy. Further work is needed to clarify the clinical utility of recompression therapy for spinal injury as a common symptom of DCI. We also point out that the Japanese decree "Ordinance on Safety and Health of Work under High Pressure", which describes work under hyperbaric environments, has some serious issues and should be amended on the basis of scientific evidence.

[New Therapeutic Strategies and Future Issues in Hyperbaric Medicine].

Hyperbaric medicine includes two different medical fields: hyperbaric oxygenation (HBO) as emergency and intensive care, and diving medicine. Recent topics in hyperbaric therapy include radiation oncology and regenerative medicine. Of special interest are clinical studies of radiotherapy after HBO that were conducted at some institutes to evaluate its therapeutic effects for cancer patients. A few studies have shown that HBO improves memory disturbance following traumatic brain injury and hypoxic and ischemic events. There is a great possibility that HBO enhances the therapeutic effects of radiotherapy and potentiates regenerative medicine. Randomized controlled trials, however, have indicated the re-examination of its viable treatment effects in some conditions, including decompression illness, carbon monoxide poisoning, and serious soft tissue infection. As recent trends in the treatment of decompression illness have changed on the basis of clinical series, the laws related to diving and caisson work should be amended in the future.

Cerebrospinal vascular diseases misdiagnosed as decompression illness: the importance of considering other neurological diagnoses.

The diagnosis of decompression illness (DCI), which is based on a history of decompression and clinical findings, can sometimes be confounded with other vascular events of the central nervous system. The authors report three cases of divers who were urgently transported to a hyperbaric facility for hyperbaric oxygen treatment of DCI which at admission turned out to be something else. The first case, a 45-year-old experienced diver with unconsciousness, was clinically diagnosed as having experienced subarachnoid hemorrhage, which was confirmed by CT scan. The second case, a 49-year-old fisherman with a hemiparesis which occurred during diving, was diagnosed as cerebral stroke, resulting in putaminal hemorrhage. The third case, a 54-year-old fisherman with sensory numbness, ataxic gait and urinary retention following sudden post-dive onset of upper back pain, was diagnosed as spinal epidural hematoma; he also showed blood collection in the spinal canal. Neurological insults following scuba diving can present clinically with confusing features of cerebral and/or spinal DCI. We emphasize the importance of considering cerebral and/or spinal vascular diseases as unusual causes of neurological deficits after or during diving.

Potential roles of hyperbaric oxygenation in the treatments of brain tumors.

Over the past 50 years hyperbaric oxygen (HBO2) therapy has been used in a wide variety of medical conditions, and one of them is cancer. Many clinical studies have been conducted to evaluate potential therapeutic effects of HBO2 as a part of cancer treatment. This review briefly summaries the potential role of HBO2 therapy in the treatment of malignant tumors and radiation injury of the brain. HBO2 therapy is used for the enhancement of radiosensitivity in the treatment of some cancers, including malignant brain tumors. Radiotherapy within 15 minutes following HBO2 exposure, a relatively new treatment regimen, has been studied at several institutes and has demonstrated promising clinical results for malignant gliomas of the brain. HBO2 therapy also increases sensitivity to some antineoplastic agents; non-randomized clinical trials using carboplatin-based chemotherapy combined with HBO2 show a significant advantage in survival for recurrent malignant gliomas. The possibilities of combining HBO2 therapy with radiotherapy and/or chemotherapy to overcome newly diagnosed and recurrent malignant gliomas deserve extensive clinical trials. HBO2 therapy also shows promising potential for the treatment and/or prevention of radiation injury of the brain after stereotactic radiosurgery for brain lesions. The possibilities with HBO2 to enhance the therapeutic effect of irradiation per se, and to even increase the radiation dose if there are ways to combat the side effects, should boost new scientific interest into the whole field of oncology looking for new armamentaria to fight cancer.

Old but new methods in radiation oncology: hyperbaric oxygen therapy.

The presence of hypoxic tumor cells is widely regarded as one of the main reasons behind the failure to control malignant tumors with radiotherapy treatments. Since hyperbaric oxygenation (HBO) improves the oxygen supply to the hypoxic tumor cells, HBO therapy has previously been used in combination with simultaneous radiotherapy to treat malignant tumors. In some clinical trials, significant improvements in local control and survival have been seen in cancers of the head and neck and the uterine cervix. However, the delivery of simultaneous HBO therapy and radiotherapy is both complex and time-consuming, with some trials reporting increased side effects. As a result, the regimen of HBO therapy in combination with simultaneous radiotherapy has yet to be used as a standard treatment for malignant tumors. In recent years, however, radiotherapy immediately after HBO therapy has been emerging as an attractive approach for overcoming hypoxia in cancer treatment. Several studies have reported that radiotherapy immediately after HBO therapy was safe and seemed to be effective in patients with high-grade gliomas. Also, this approach may protect normal tissues from radiation injury. To accurately estimate whether the delivery of radiotherapy immediately after HBO therapy can be beneficial in patients with high-grade gliomas and other cancers, further prospective studies are warranted.

Repetitive breath-hold diving causes serious brain injury.

We report on a Japanese male professional breath-hold diver (Ama) who developed neurological disorders during repetitive dives to 22 meters of sea water. Each diving duration and surface interval were 40-80 seconds and 20-30 seconds, respectively. He suffered from sensory numbness of the right cheek, hand and foot, and double vision after more than two hours of consecutive dives. Magnetic resonance images of his brain showed multiple cerebral infarcts, and one of the lesions was situated in the brainstem. There is a possibility that repetitive deep breath-hold dives with short surface intervals can induce fatal accidents for divers.

[Utility of hyperbaric oxygenation in radiotherapy for malignant brain tumors--a literature review].

Over the past 50 years, hyperbaric oxygenation (HBO) therapy has been used in a wide variety of medical conditions; this theraphy causes an increase in oxygen tension in blood and tissues. In the treatment of malignant gliomas, HBO therapy is used for the radiosensitization of cells in combination with radiotherapy (RT). Further, HBO therapy is applied for the treatment and prevention of radiation-induced brain necrosis that is the most serious complication observed after radiosurgery. We reviewed the literature to evaluate the manner in which HBO therapy contributes to clinical fields in cases of RT administration for malignant brain tumors.

Influence of tea and coffee on biomonitoring of toluene exposure.

BACKGROUND: The intake of some benzoic acid-containing foods or drinks such as green tea and coffee is known to increase urinary hippuric acid (HA) concentrations, and, unless this can be accounted for, may result in false-positive findings during the biological monitoring of toluene exposure. AIMS: To investigate the influence of green tea and coffee ingestion on urinary HA concentrations. METHODS: Time-weighted average exposures to toluene were monitored by measuring urinary HA in 245 car painters in 2005 and again in 2006. Samples of both urine and blood were collected during work hours. All the participants were also asked about their alcohol intake, smoking and dietary and beverage habits, especially green tea and coffee. To clarify the relationship between green tea and coffee ingestion, workers were prohibited from consuming green tea and coffee for 1 day before the health check-up in 2006. RESULTS: The frequency of positive urinary HA concentrations (>1.0 g/l) in heavy consumers of green tea and/or coffee was significantly higher than that of the non-consumer or light consumers (OR 2.34, 95% CI 1.15-4.74). Prohibiting green tea and coffee ingestion was effective in decreasing the frequency of falsely elevated urinary HA concentrations (P < 0.01). CONCLUSIONS: The consumption of green tea and/or coffee can result in an overestimation of urinary HA concentrations and cause false-positive results during the biological monitoring of workers exposed to low doses of toluene.

Fractionated stereotactic radiotherapy using gamma unit after hyperbaric oxygenation on recurrent high-grade gliomas.

BACKGROUND: To reduce this complication and to enhance the radiation effect to hypoxic cells of high-grade gliomas, the authors performed noninvasive fractionated stereotactic radiotherapy (FSRT) using a Gamma unit combined with hyperbaric oxygen (HBO) therapy for the treatment of recurrent disease. PATIENTS AND METHODS: Twenty-five consecutive patients who had previously received radiotherapy with chemotherapy for recurrent high-grade gliomas, including 14 patients with anaplastic astrocytoma (AA) and 11 with glioblastoma multiforme (GBM), underwent Gamma FSRT immediately after HBO therapy (2.5 atmospheres absolute for 60 min). The Gamma FSRT was repeatedly performed using a relocatable head cast. Median tumor volume was 8.7 cc (range, 1.7-159.3 cc), and the median total radiation dose was 22 Gy (range, 18-27 Gy) to the tumor margin in 8 fractions. RESULTS: Actuarial median survival time after FSRT was 19 months for patients with AA and 11 months for patients with GBM, which was significantly different (P = 0.012, log-rank test). Two patients underwent subsequent second FSRT for regional or remote recurrence. Seven patients (28%) underwent subsequent craniotomies and resections at a mean of 8.4 months after FSRT treatment, and 4 of them had radiation effects without viable cells and remained alive for 50-78 months. CONCLUSION: Gamma FSRT after HBO therapy appears to confer a survival benefit for patients with recurrent high-grade gliomas and warrants further investigation.

Effect of prophylactic hyperbaric oxygen treatment for radiation-induced brain injury after stereotactic radiosurgery of brain metastases.

PURPOSE: The purpose of the present study was to evaluate the prophylactic effect of hyperbaric oxygen (HBO) therapy for radiation-induced brain injury in patients with brain metastasis treated with stereotactic radiosurgery (SRS). METHODS AND MATERIALS: The data of 78 patients presenting with 101 brain metastases treated with SRS between October 1994 and September 2003 were retrospectively analyzed. A total of 32 patients with 47 brain metastases were treated with prophylactic HBO (HBO group), which included all 21 patients who underwent subsequent or prior radiotherapy and 11 patients with common predictors of longer survival, such as inactive extracranial tumors and younger age. The other 46 patients with 54 brain metastases did not undergo HBO (non-HBO group). The radiation-induced brain injuries were divided into two categories, white matter injury (WMI) and radiation necrosis (RN), on the basis of imaging findings. RESULTS: The radiation-induced brain injury occurred in 5 lesions (11%) in the HBO group (2 WMIs and 3 RNs) and in 11 (20%) in the non-HBO group (9 WMIs and 2 RNs). The WMI was less frequent for the HBO group than for the non-HBO group (p = 0.05), although multivariate analysis by logistic regression showed that WMI was not significantly correlated with HBO (p = 0.07). The 1-year actuarial probability of WMI was significantly better for the HBO group (2%) than for the non-HBO group (36%) (p < 0.05). CONCLUSIONS: The present study showed a potential value of prophylactic HBO for the radiation-induced WMIs, which justifies further evaluation to confirm its definite benefit.

Successful treatment of cervical spinal epidural abscess by combined hyperbaric oxygenation.

A 49-year-old man underwent hyperbaric oxygen (HBO) therapy for the treatment of primary spinal epidural abscess. Although the epidural abscess was initially treated with antibiotic (cefozopran) for 5 days, he subsequently developed motor weakness, paresthesia and urinary retention. MRI demonstrated spinal cord compression at the C1-C4 level. HBO therapy was added to the antibiotic regimen, and three days later we found clinical evidence of a response to treatment. Neurological symptoms were relieved 13 days after HBO therapy. This case suggests that HBO therapy is an effective therapeutic adjunct for the treatment of spinal epidural abscess.

[Hyperbaric oxygen therapy for neurologic emergency and neurosurgical diseases: a systematic review of the literature].

I have reviewed reports concerning neurologic emergency and neurosurgical diseases adjunctively treated with hyperbaric oxygen (HBO) therapy. Some clinical studies indicate the favorable effects of HBO therapy on the events at an ultra-acute stage of brain ischemia. This therapy has been used in the treatments of other neurologic emergency diseases, such as brain and spinal injury, carbon monoxide intoxication, decompression illness involving the central nervous system and so on. Some reports clarify that patients with malignant gliomas have a prolonged survival by radiotherapy after HBO therapy. In addition, I have applied HBO preexposure to radiosurgical treatments for recurrent and brain stem gliomas. HBO therapy enhances the effects of some chemotherapeutic agents such as platinum drugs and nitrosoureas. Especially, the therapeutic effect of carboplatin, one of platinums, is improved by HBO therapy in recurrent malignant tumors. Although radiation-induced brain injury is the most serious problem after radiosurgery, HBO therapy controls this condition and its progression. Wound infection after intracranial or spinal surgery is well controlled by anti-infectious drugs combined with HBO therapy. Now HBO therapy is an important therapeutic option in the fields of neurologic emergency and neurosurgery. However, high-quality randomized controlled trials that evaluate the short- and long-term risks and benefits of HBO therapy are necessary to better inform clinical decisions.

[Central nervous system involvement in patients with decompression illness].

Dysbarism or decompression illness (DCI), a general term applied to all pathological changes secondary to altered environmental pressure, has two forms decompression sickness (DCS) and arterial gas embolism (AGE) after pulmonary barotrauma. Cerebral and spinal disorders have been symptomatically categorized as AGE and DCS, respectively. Magnetic resonance images (MRIs) of divers with DCI showed multiple cerebral infarction in the terminal and border zones of the brain arteries. In addition, there were no differences between MRI findings for compressed air and breath-hold divers. Although the pathogenesis of the brain is not well understood, we propose that arterialized bubbles passing through the lungs and heart involved the brain. From the mechanisms of bubble formation, however, this disorder has been classified as DCS. We propose that there is a difference between clinical and mechanical diagnoses in the criteria of brain DCI. In contrast to brain injury, the spinal cord is involved only in compressed air divers, and is caused by disturbed venous circulation due to bubbles in the epidural space. The best approach to prevent diving accidents is to make known the problems for professional and amateur divers.

Successful treatment of radiation-induced brain necrosis by hyperbaric oxygen therapy.

We describe a 68-year-old man who underwent hyperbaric oxygen (HBO) therapy to manage radiation necrosis of the brain, which developed after two treatments with stereotactic radiosurgery (SRS) to the same lesion. The necrosis was subsequently treated with steroids alone for 2 months; however, he progressed clinically and radiographically. Improvement again was noted with the reinstitution of HBO therapy. This case suggests that HBO therapy is an important therapeutic option in the treatment of brain radiation necrosis caused by SRS.

Severe skin ulceration associated with Wegener's granulomatosis: successful treatment with hyperbaric oxygen and prostaglandin E1.

Abstract A 36-year-old woman patient with intractable skin ulcers associated with Wegener's granulomatosis was successfully cured by combination therapy with hyperbaric oxygenation therapy (HBO) and intravenous prostaglandin E1 (PGE1). Treatment for 4 months with prednisolone, intravenous PGE1, and cyclophosphamide did not result in healing of the multiple skin lesions on her legs. Repeated HBO with intravenous PGE1 therapy over 6 months resulted in a complete healing of the skin ulcers. We recommend the use of HBO combined with PGE1 for severe cutaneous lesions associated with generalized vasculitis.