Effects of training flights of combat jet pilots on parameters of airway function, diffusing capacity and systemic oxidative stress, and their association with flight parameters.

BACKGROUND: Fighter aircraft pilots are regularly exposed to physiological challenges from high acceleration (Gz) forces, as well as increased breathing pressure and oxygen supply in the support systems. We studied whether effects on the lung and systemic oxidative stress were detectable after real training flights comprising of a wide variety of exposure conditions, and their combinations. METHODS: Thirty-five pilots of the German Air Force performed 145 flights with the Eurofighter Typhoon. Prior to and after flight lung diffusing capacity for carbon monoxide (DLCO) and nitric oxide (DLNO), alveolar volume (VA), and diffusing capacities per volume (KCO, KNO) were assessed. In addition, the fractional concentration of exhaled nitric oxide (FeNO) was determined, and urine samples for the analysis of molecular species related to 8-hydroxy-2'-deoxyguanosine (8-OHdG) were taken. For statistical analysis, mixed ANOVA models were used. RESULTS: DLNO, DLCO, KNO, KCO and VA were reduced (p < 0.001) after flights, mean ± SD changes being 2.9 ± 5.0, 3.2 ± 5.2, 1.5 ± 3.7, 1.9 ± 3.7 and 1.4 ± 3.1%, respectively, while FeNO decreased by 11.1% and the ratio of 8-OHdG to creatinine increased by 15.7 ± 37.8%. The reductions of DLNO (DLCO) were smaller (p < 0.001) than those of KNO (KCO). In repeated flights on different days, baseline values were restored. Amongst various flight parameters comprising Gz-forces and/or being indicative of positive pressure breathing and oxygenation support, the combination of long flight duration and high altitude appeared to be linked to greater changes in DLNO and DLCO. CONCLUSIONS: The pattern of reductions in diffusing capacities suggests effects arising from atelectasis and increased diffusion barrier, without changes in capillary blood volume. The decrease in exhaled endogenous NO suggests bronchial mucosal irritation and/or local oxidative stress, and the increase in urinary oxidized guanosine species suggests systemic oxidative stress. Although changes were small and not clinically relevant, their presence demonstrated physiological effects of real training flights in a modern 4th generation fighter jet.

A comparison of breath- and blood-alcohol test results from real-life policing situations: a one-year study of data from the Central Hessian police district in Germany.

So far, studies investigating the comparability of breath alcohol concentration (BrAC) with blood alcohol concentration (BAC) have focused on the accuracy of BrAC testing instruments. The presented study, conducted with cases from the district of the Middle Hessian Police Headquarters, is to the best of our knowledge the first to compare both methods under real-life conditions in normal policing situations. For a 1-year period, alcohol-impaired drunk-driving suspects, who were by criminal procedure required to give a blood sample, were offered a voluntary, additional BrAC test with a "Dräger Alcotest 7110 Evidential". The BrAC test was to be administered as soon as possible after the suspect had been apprehended, without, however, delaying the collection of the blood sample. Ninety-two cases could be included in our study. In 30 cases, a blood sample was not taken; in 11 cases, a BrAC test could not be performed. In the remaining 51 cases, we found the following pairings of BrAC and BAC results: BrAC≥0.55 mg/l and BAC≥1.1‰ (n=39); 0.25 mg/l≤BrAC<0.55 mg/l and 0.5‰≤BAC<1.1‰ (n=5); BrAC≥0.55 mg/l and BAC<1.1‰ (n=4); BrAC<0.55 mg/l and BAC≥1.1‰ (n=3). The mean value for the conversion factor, Q, was 2.12‰l/mg. In accord with numerous other studies, our study results would suggest a value of 2.1‰ l/mg to German legislature as a new statutory value for Q. In borderline cases, of which there were already 7 in our study with 51 cases, suspects could benefit both from a BrAC test or a BAC test, with the benefit lastly depending more on early testing time than on the test method used. Our results support the call for the earliest possible measurement of alcohol concentration values after a drunk driving offense was committed. In some situations, this can probably only be accomplished with BrAC testing. A supplementary blood sample and BAC testing could compensate for the known weaknesses of BrAC testing. Thus, the complementary use of both methods might be a viable option.