The close relationship between decreases in extracellular GABA concentrations and increases in the incidence of hyperbaric oxygen-induced electrical discharge.

To elucidate the mechanism by which hyperbaric oxygen (HBO2) induces electrical discharge, changes in the extracellular concentrations of GABA and glutamate were measured every 5 min using a microdialysis technique in rats during a period of exposure to HBO2 (5 atm abs). Electrical discharge was observed at 28 +/- 4 min after the onset of exposure. Though the extracellular concentrations of glutamate remained unchanged, the extracellular GABA concentrations (pre-exposure level, 0.026 +/- 0.005 microM in dialysate) began to decrease 15 min after the onset of exposure and reached their lowest level (74 +/- 14%, 0.019 +/- 0.004 microM) at the time of appearance of the discharge. There was a close logistic relationship between extracellular GABA concentrations and the discharge incidence, and the extracellular concentrations of GABA causing electrical discharge in 50% of the animals were estimated to be 80% of the pre-exposure level. These results suggest a possible mechanism that HBO2 exposure-induced discharge is caused by the decrease in extracellular concentration of GABA.</p

Effects of Antibiotics Administration on the Incidence of Wound Infection in Percutaneous Dilatational Tracheostomy

The effect of antibiotics during the perioperative period of percutaneous dilatational tracheostomy (PDT) is still controversial. A total of 297 patients who underwent the PDT procedure were divided into 2 groups:those administered antibiotics perioperatively and those not administered antibiotics. Wound infections were noted in 7 cases (incidence rate, 2.36%) and no death was recorded. Of the 69 patients without antibiotics, 5 developed wound infections (incidence rate, 7.25%), while only 2 of the 228 patients with antibiotics developed wound infections (incidence rate, 0.88%) (p＝0.002;risk ratio, 8.82;95% confidence interval, 1.67-46.6). Of the 7 cases of wound infection, 5 cases occurred during the early period after PDT (within 7 days). Collectively, the present results suggest that prophylactic administration of antibiotics may prevent the incidence of PDT-induced wound infection, especially in the early phase after the PDT procedures. The need for antibiotics in PDT should be reconsidered

An epidemiologically rare case of Vibrio vulnificus infection that occurred in October in an inland city of Japan

　A 68-year-old man with alcohol addiction, who lived in the suburbs of Tsuyama, an inland city located in northeast Okayama prefecture, was transported to the emergency unit of the Tsuyama Central Hospital in a state of cardiopulmonary arrest (CPA). Despite rigorous systemic investigation and treatment, the patient died 2 hours after arrival. After his death, Vibrio vulnificus was isolated from his blood culture. 　Vibrio vulnificus causes fatal infection in humans, usually only in areas located close to the sea where appropriate temperature and suitable salt concentration for its growth are available. Therefore, its occurrence is epidemiologically restricted ; in Japan, the western coastal areas, especially in summers, are reported to be the high-risk regions. This is a rare case because it occurred in a city approximately 50 kilometers from both the Sea of Japan and the Pacific coast of Okayama, and at the end of October in 2011. Economic development and distribution systems have made it possible to transport various food products from coastal areas or abroad to any place in a short time, such that these infections can potentially develop in areas other than expected. We should be aware of the increasing risk of Vibrio vulnificus infection during any season and at any place, especially in patients with abnormal liver function

Portal Venous Gas Following Ingestion of Hydrogen Peroxide Successfully Treated with Hyperbaric Oxygen Therapy

The primary toxicity of hydrogen peroxide results from its interaction with catalase, which liberates water and oxygen. We report the case of a 14-year-old Japanese girl with portal venous gas that was caused by oxygen liberated from intentionally ingested hydrogen peroxide. Although she had a past history of atrial septal defect, recovery without cardiac or neurological sequelae was achieved using hyperbaric oxygen therapy. Emergency physicians must be aware of the danger of liberated oxygen due to hydrogen peroxide ingestion

Current status of delirium assessment tools in the intensive care unit: a prospective multicenter observational survey

Delirium is a critical challenge in the intensive care unit (ICU) or high care unit (HCU) setting and is associated with poor outcomes. There is not much literature on how many patients in this setting are assessed for delirium and what tools are used. This study investigated the status of delirium assessment tools of patients in the ICU/HCU. We conducted a multicenter prospective observational study among 20 institutions. Data for patients who were admitted to and discharged from the ICU/HCU during a 1-month study period were collected from each institution using a survey sheet. The primary outcome was the usage rate of delirium assessment tools on an institution- and patient-basis. Secondary outcomes were the delirium prevalence assessed by each institution's assessment tool, comparison of delirium prevalence between delirium assessment tools, delirium prevalence at the end of ICH/HCU stay, and the relationship between potential factors related to delirium and the development of delirium. Result showed that 95% of institutions used the Intensive Care Delirium Screening Checklist (ICDSC) or the Confusion Assessment Method for the ICU (CAM-ICU) to assess delirium in their ICU/HCU, and the remaining one used another assessment scale. The usage rate (at least once during the ICU/HCU stay) of the ICDSC and the CAM-ICU among individual patients were 64.5% and 25.1%, and only 8.2% of enrolled patients were not assessed by any delirium assessment tool. The prevalence of delirium during ICU/HCU stay was 17.9%, and the prevalence of delirium at the end of the ICU/HCU stay was 5.9%. In conclusion, all institutions used delirium assessment tools in the ICU/HCU, and most patients received delirium assessment. The prevalence of delirium was 17.9%, and two-thirds of patients had recovered at discharge from ICU/HCU