Shunt-mediated decompression sickness in a compressed air worker with an atrial septal defect.

We report a compressed air worker who had diffuse cutaneous decompression sickness with pain in his left shoulder and visual disturbance characteristic of migraine aura after only his third hyperbaric exposure. The maximum pressure was 253 kPa gauge with oxygen decompression using the Swanscombe Oxygen Decompression Table. He was found to have a very large right-to-left shunt across a 9 mm atrial septal defect. He had transcatheter closure of the defect but had some residual shunting with release of a Valsalva manoeuvre. Thirty-two other tunnel workers undertook the same pressure profile and activities in the same working conditions during the maintenance of a tunnel boring machine for a total of 233 similar exposures and were unaffected. As far as we are aware this is the first report of shunt-mediated decompression sickness in a hyperbaric tunnel worker in the United Kingdom and the second case reported worldwide. These cases suggest that shunt-mediated decompression sickness should be considered to be an occupational risk in modern compressed air working. A right-to-left shunt in a compressed air worker should be managed in accordance with established clinical guidance for divers.

Butylated hydroxytoluene can protect polyunsaturated fatty acids in dried blood spots from degradation for up to 8 weeks at room temperature.

BACKGROUND: Dried blood spots (DBS) from fingertip prick blood can enable high throughput fatty acid profiling but may be prone to lipid peroxidation during storage. The use of butylated hydroxytoluene (BHT) on chromatography paper can prevent polyunsaturated fatty acid (PUFA) loss but examinations on the length of storage times possible are not comprehensive. METHOD: In the first study, venous whole blood was saturated on paper strips pre-soaked with 0, 2.5 or 5.0 mg/mL BHT and exposed to air for up to 28 days. In a second study, the effect of sealing DBS on 5.0 mg/mL BHT-soaked chromatography strips in capped test tubes or vacuum sealed polypropylene bags with and without nitrogen purging was examined over eight weeks. The fatty acid composition of the DBS were determined by gas chromatography and the effect of sample storage on omega-3 biomarkers were examined. RESULTS: PUFA and omega-3 biomarkers in DBS stored without BHT were dramatically reduced by day 3. In general, BHT delayed decreases in eicosapentaenoic + docosahexaenoic acid from baseline (3.2 ± 0.2 wt%) to 28 days (2.6 ± 0.03 wt%) of storage. In the % n-3 highly unsaturated fatty acids (HUFA) in total HUFA biomarker, BHT was more effective at preventing changes, particularly with 5.0 mg/mL BHT where no differences were detected up to 28 days. Sealed storage with BHT tended to increase the stability of the PUFA in DBS and nitrogen purging did not appear to provide additional benefits. The % n-3 HUFA in total HUFA biomarker also appeared to be more stable in the sealed storage study. CONCLUSIONS: The storage of DBS in sealed containers with BHT may prevent PUFA degradation for up to 8 weeks. The % n-3 HUFA in total HUFA biomarker appears to provide a more consistent assessment of omega-3 status throughout storage as compared with other omega-3 blood biomarkers.

Biomarker and dietary validation of a Canadian food frequency questionnaire to measure eicosapentaenoic and docosahexaenoic acid intakes from whole food, functional food, and nutraceutical sources.

BACKGROUND: Canadian dietary sources of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) include marine and non-marine whole foods, functional foods, and nutraceuticals. OBJECTIVE/DESIGN: In the present study, these sources were incorporated into a nutrient-specific, semi-quantitative food frequency questionnaire (FFQ) and the ability to measure the EPA and DHA intakes of Canadian adults was assessed. Specifically, the EPA and DHA intakes estimated by FFQ of 78 men and women, 20 to 60 years of age, were compared with EPA and DHA measurements from 3-day food records and measures of EPA and DHA in fasting whole blood. RESULTS: Mean (±standard deviation) and median intakes of EPA+DHA were 0.34±0.34 and 0.21 g/day by FFQ and 0.47±0.71 and 0.13 g/day by food record, with no significant differences between mean intakes (P=0.93). The FFQ provided higher estimates than the food record at low intakes of EPA and DHA and lower estimates at high intakes based on Bland-Altman plots. The FFQ was moderately correlated with food record (r=0.31 to 0.49) and with blood biomarker measures of EPA and DHA (r=0.31 to 0.51). Agreement analysis revealed that 42% of participants were classified in the same and 77% into same or adjacent quartile when EPA and DHA intake was assessed by food record and by FFQ. Similar quartile agreement was found for EPA and DHA intakes by FFQ with blood biomarker EPA and DHA. The range of the validity coefficients, calculated using the method of triads, was 0.43 to 0.71 for FFQ measurement of EPA+DHA. CONCLUSIONS: The FFQ is an adequate tool for estimating usual EPA and DHA intakes and ranking Canadian adults by their intakes.

Direct quantitation of omega-3 fatty acid intake of Canadian residents of a long-term care facility.

An increased dietary intake of n-3 highly unsaturated fatty acids (HUFA; >or=20 carbons, >or=3 carbon-carbon double bonds), particularly eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), is associated with the decreased risk and incidence of several morbidities afflicting the elderly, including cognitive decline, dementia, rheumatoid arthritis, and macular degeneration. In this study, the dietary intake and blood levels of fatty acids were directly determined in residents of a retirement home or assisted living phase of a continuum of care facility for Canadian seniors. Finger-tip-prick blood samples, 3-day food duplicates, and 3-day food records were collected. The fatty acid composition of food duplicates and blood was determined by gas chromatography. Fifteen participants (7 male, 8 female; 87.1 +/- 4.8 years of age) completed the protocol. The daily intake of EPA and DHA combined, determined directly, was 70 mg (95% CI, 41-119) or 0.036% of total energy (95% CI, 0.022-0.058). In finger-tip-prick blood, the percent of n-3 HUFA in total HUFA of whole blood, a biomarker of n-3 polyunsaturated fatty acid status, was 28.8 +/- 5.2%. Correlations between daily n-3 HUFA intake and n-3 HUFA in blood were not significant (r = 0.14; n = 15), but became significant after the removal of 2 participants who appeared to consume fish irregularly (r = 0.59; n = 13). The n-3 HUFA intake and corresponding n-3 HUFA blood levels of Canadian long-term care residents are lower than levels estimated to prevent several morbidities associated with aging.