RESUMO
INTRODUCTION/BACKGROUND: Artisanal fishermen dive for sustenance. The lifetime prevalence of decompression sickness (DCS) in this population is alarmingly high. We wanted to understand the level of decompression stress fishermen in this region of the Yucatán experience in their daily fishing effort. We used a mathematical model to quantify nitrogen-loading in a nine-tissue compartment model. MATERIALS AND METHODS: Approved by the UCLA IRB 2 #13-000532, this study was conducted during fishing seasons 2012 through 2017. Diving fishermen were instructed to attach dive recorders to their waists every fishing day during the study period. Sensus Ultra dive recorders (ReefNet Inc.), with an accuracy of ±1 foot of seawater (fsw), 0.304 meters, and an activation depth of 10 fsw, 3.04 meters, were used to record dive parameters. Sampling interval was set to 10 seconds. A program in RStudio was created to extract the dive profiles of each fishing day and curtail into single-line outputs: pressure, time, date, start of dive and end of dive. An exponential decay formula was used to calculate the nitrogen-loading pressures for nine theoretical tissue compartments. Final nitrogen pressure, controlling compartments, decompression stop and time at stop were calculated. RESULTS: Fishermen completed 4,961 dives over 1,758 diving days during the study period. The 40-minute compartment controlled most of the dives. The 80-minute compartment controlled 5%-20% of dives two through five. Decompression stop times for the last dive ranged from one minute to 190 minutes. Most of the required stop time observed was seen at depths of 1-15 fsw.
Assuntos
Doença da Descompressão/prevenção & controle , Descompressão/métodos , Mergulho/fisiologia , Modelos Teóricos , Nitrogênio/análise , Doenças Profissionais/prevenção & controle , Adulto , Confiabilidade dos Dados , Coleta de Dados/instrumentação , Coleta de Dados/métodos , Descompressão/estatística & dados numéricos , Doença da Descompressão/diagnóstico , Doença da Descompressão/etiologia , Mergulho/efeitos adversos , Mergulho/estatística & dados numéricos , Pesqueiros , Humanos , Masculino , México , Pessoa de Meia-Idade , Doenças Profissionais/diagnóstico , Doenças Profissionais/etiologia , Estações do Ano , Água do Mar , Software , Fatores de Tempo , Adulto JovemRESUMO
It is reported that more than 75% of 400 artisanal fisherman divers working off the Yucatan Peninsula experience decompression sickness (DCS) each year, making DCS an epidemic in this region. These divers use primitive hookah diving support systems (HDSS). Breathing air is supplied from inadequately filtered and poorly maintained gasoline-powered air compressors. We hypothesized that air supplies could be contaminated. Air contamination could produce symptoms consistent with some presentations of DCS. This could confound and falsely elevate the true incidence of DCS. A cross-sectional study was undertaken in a fishing community. Ten fishermen from a single cohort participated. Fishermen were instructed not to drain volume tanks following their last dive of the day before their diving air was sampled. Dräger carbon monoxide (CO) 5/a-P and carbon dioxide (CO2) 100/a Short-term Tubes were used to measure 1.0 liters (L) of gas through a Visi-Float flow meter at 0.2 L/minute. Average CO value was 42 ppm (8-150 ppm). Average CO2 was 663 ppm (600-800). Measurements exceeded recommended diving norms for CO of 20 ppm. CO2 exceeded one diving organization recommendation of 500 ppm. Separation of engine exhaust from compressor intake could decrease CO values in HDSS to acceptable standards thus eliminating one possible confounder from this DCS epidemic.