The effect of hyperbaric oxygen therapy on rhabdomyolysis-induced myoglobinuric acute renal failure in rats.

Myoglobinuric acute renal failure (MARF) may develop after severe muscle injury. Heme oxygenase-1 (HO-1), a stress-response protein, has been implicated as a protective agent against MARF. We hypothesized that hyperbaric oxygen therapy (HBOT) may alleviate MARF by inducing renal HO-1 expression. Wistar-Albino rats were randomly assigned into three groups: Control (n = 4), MARF (n = 8), MARF + HBO (n = 8). MARF was induced by intramuscular glycerol (50%, 8 mL/kg) injection. Saline (8 mL/kg) was injected into the hind limb of the animals in the control group. Animals in the MARF + HBO group received two sessions of HBO therapy (90 min at 2.5 atm) 2 and 18 h after glycerol injection. Serum and tissue samples were taken at 24 h. Serum urea and creatinine levels increased in the MARF and MARF + HBO groups confirming the development of MARF. But, serum urea and creatinine levels were similar in MARF and MARF + HBO groups. Oxidative stress parameters were similar among all groups. Histological renal injury score was similar in MARF and MARF + HBO groups. HO-1 level, determined by immunohistochemistry, was significantly higher in MARF and MARF + HBO groups, compared to the control group. Although HO-1 level in MARF + HBO group was higher than MARF group, it was not statistically significant. We found that HBOT did not reduce renal injury in experimental MARF model. HBOT is used to reduce the muscle damage after crush injury, which may be accompanied by MARF. Therefore, more studies are needed to understand the effects of HBO treatment on renal functions after MARF.

Requests for emergency hyperbaric oxygen treatment for carbon monoxide poisoning in Ankara, Turkey.

BACKGROUND: Carbon monoxide (CO) poisoning is common in Turkey. Our department is the main provider of emergency hyperbaric oxygen therapy (HBOT) in Ankara and neighboring cities. In this study, we analyzed the characteristics of CO-poisoned patients who were referred by phone to our department for emergency HBOT. METHODS: We retrospectively reviewed the records of phone consultations with emergency departments regarding the need for treatment of CO-poisoned patients with HBOT between 14 January 2014 and 14 January 2015. The following information was extracted from medical records: age, gender, CO source, exposure duration, carboxyhemoglobin (COHb) level, symptoms, electrocardiography (ECG) findings, cardiac enzymes, pregnancy, the distance of referring hospital to our centre, time between admission and consultation and HBOT decision. RESULTS: Over the one-year period, 562 patients with CO poisoning were referred for HBOT. We recommended HBOT for 289 (51%) patients. HBOT was recommended for 58% (n = 194) of the patients with COHb ≥ 25%, 72% (n = 163) of the patients with a history of syncope, 67% (n = 35) of the patients with ECG abnormality, and 67% (n = 14) of pregnant patients. Patients for whom HBOT was not recommended despite having positive signs of severe poisoning were referred significantly later compared to patients for whom HBOT was recommended. CONCLUSION: We found that the duration from admission to an emergency department to HBOT consultation affected our decision-making.

Early treatment response predicts outcome in patients with idiopathic sudden sensorineural hearing loss treated with hyperbaric oxygen therapy.

Hyperbaric oxygen (HBO2) therapy is used in the treatment of idiopathic sudden sensorineural hearing loss (ISSNHL). Some patients, however, do not benefit from HBO2 therapy despite several weeks of treatment. We hypothesized that early treatment response could predict treatment failure. We conducted a retrospective chart review and identified patients diagnosed with ISSNHL and recorded the pure tone average (PTA) levels prior to, after the first week and at completion of HBO2 therapy. Early treatment response (ETR) was assessed after the first week of HBO2 therapy, and an increase ⟨10 decibels (dB) in mean PTA level was defined as a negative ETR. Factors associated with no recovery were determined using logistic regression analysis. Overall, 39 patients (22 males; mean age (±SD) 41.9 ±14.3 years) were assessed. At treatment completion, the improvement in hearing was 'very substantial' (≥20 dB) for 21 patients (53.8%), 'substantial' (10-19 dB) for eight (20.5%), 'minimal' (⟨10 dB) for five (12.8%) and absent for five (12.8%) patients. After the first week of HBO2 therapy, 18 (46.2%) patients displayed negative ETR. Multivariate logistic regression analysis revealed 'negative ETR' as the only significant predictor of treatment failure (odds ratio (95% confidence interval): 6.98 (1.59-30.61), p=0.010) in patients with ISSNHL treated with HBO2. In conclusion, we found that patients who fail to benefit from an initial set of HBO2 sessions were less likely to benefit from additional HBO2 sessions. Further prospective studies are necessary to confirm our findings.