Use of hyperbaric oxygen therapy for preventing delayed neurological sequelae in patients with carbon monoxide poisoning: A multicenter, prospective, observational study in Japan.

BACKGROUND: The purpose of this study was to clarify the practical clinical treatment for acute carbon monoxide (CO) poisoning in Japan and to investigate the efficacy of hyperbaric oxygen (HBO2) therapy in preventing delayed neurological sequelae (DNS) in the acute phase of CO poisoning. METHODS: We conducted a multicenter, prospective, observational study of acute CO poisoning in Japan. Patients with acute CO poisoning were enrolled and their treatment details were recorded. The primary endpoint was the onset of DNS within 2 months of CO exposure. Factors associated with DNS were assessed with logistic regression analysis. RESULTS: A total of 311 patients from 57 institutions were registered and 255 were analyzed: 171 received HBO2 therapy (HBO2 group) and 84 did not (normobaric oxygen [NBO2] group). HBO2 therapy was performed zero, once, twice, or three times within the first 24 h in 1.8%, 55.9%, 30.9%, and 11.3% of the HBO2 group, respectively. The treatment pressure in the first HBO2 session was 2.8 ATA (47.9% of the HBO2 group), 2.0 ATA (41.8%), 2.5 ATA (7.9%), or another pressure (2.4%). The incidence of DNS was 13/171 (7.6%) in the HBO2 group and 3/84 (3.6%) in the NBO2 group (P = 0.212). The number of HBO2 sessions in the first 24 h was one of the factors associated with the incidence of DNS (odds ratio, 2.082; 95% confidence interval, 1.101-3.937; P = 0.024). CONCLUSIONS: The practical clinical treatment for acute CO poisoning, including HBO2 therapy, varied among the institutions participating in Japan. HBO2 therapy with inconsistent protocols showed no advantage over NBO2 therapy in preventing DNS. Multiple HBO2 sessions was associated with the incidence of DNS.

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.