Incidence of ischemic brain lesions in hyperbaric chamber inside attendants

Concern is growing about the negative long-term effects of hyperbaric exposure on the central nervous system of divers. This study was conducted with magnetic resonance imaging (MRI) to evaluate attendants that work inside hyperbaric chambers (known as inside attendants) for hyperintense brain lesions. Ten inside attendants and 10 healthy nondiving subjects were included in the study. A questionnaire was used to obtain information about subjects' medical history, hyperbaric exposure history, alcohol intake, and smoking habits. T1-weighted, T2-weighted, and fluid-attenuated inversion recovery images were acquired with a 1.5-T MRI device. A lesion was included in the count if it was hyperintense on both T2-weighted and fluid-attenuated inversion recovery images. Although MRI revealed 3 hyperintense brain lesions in 2 of 10 inside attendants and in none of the controls, the differences between groups were not statistically significant (P=.147). The number of brain lesions counted did not correlate with the age of the inside attendants (r=0.007; P=.978), the number of hyperbaric exposures (r=-0.203; P=.574), or the duration of work as an inside attendant (r=0.051; P=.890). Investigators found a correlation, however, between the number of cigarettes smoked in a day and the number of brain lesions identified (r=0.779; P<.01). An increased incidence of hyperintense brain lesions was not observed in inside attendants who had never experienced decompression sickness compared with nondiving controls. Additional multicenter epidemiologic studies are needed if the occupational safety of inside attendants is to be enhanced.