This study measured the clothing adjustment factors (CAFs) for four clothing ensembles (Cotton Coveralls, Tyvek 1427 Coveralls, NexGen Coveralls, and Tychem QC Coveralls; all coveralls were worn without hoods) against a baseline of cotton work clothes to determine whether the CAFs would be affected by the metabolic rate. Fifteen participants wore one of the five ensembles while walking on a treadmill at low, moderate, and high rates of work in an environment maintained at 50% relative humidity. A climatic chamber was used to slowly increase the level of heat stress by increasing air temperature. When the participant's core temperature reached a steady-state, the dry bulb temperature was increased. The point at which the core temperature began to increase was defined as the inflection point, and the WBGT recorded 5 min before the inflection point was the critical WBGT for each ensemble. A three-way mixed effects linear model with ensemble by metabolic rate category interactions demonstrated that the CAF did not change with metabolic rate, so CAFs can be used over a wide range of metabolic rates. The data at the moderate metabolic rate were combined with data on 14 participants from a previous study under the same conditions. The CAFs in degrees C WBGT were 0 for cotton coveralls, 1.0 for Tyvek 1422A, and 2.5 for NexGen. Although the value of 7.5 for Tychem QC was found, the recommendation remained at 10 to account for the effects of humidity. The standard error for the determination of WBGT crit at 50% relative humidity was 1.60 degrees C WBGT.

A limiting factor for clothing ensembles inherent during heat stress exposures is the evaporative resistance, which can be used to compare candidate ensembles and in rational models of heat exchange. In this study, the apparent total evaporative resistance of five clothing ensembles (cotton work clothes, cotton coveralls, and coveralls made of Tyvek 1424 and 1427, NexGen and Tychem QC was estimated empirically from wear trials using a progressive heat stress protocol and from clothing insulation adjustments based on ISO 9920 (2007) and wetness. The metabolic rate was moderate at 165 W m(-2) and relative humidity was held at 50%. Twenty-nine heat-acclimated participants (20 men and 9 women) completed trials for all clothing ensembles. A general linear mixed effects model (ensemble and participants as a random effect) was used to analyze the data. Significant differences (p < 0.0001) among ensembles were observed for apparent total evaporative resistance. As expected, Tychem QC had the highest apparent total evaporative resistance at 0.033 kPa m(2) W(-1). NexGen was next at 0.017 kPa m(2) W(-1). These were followed by Tyvek 1424 at 0.015 kPa m(2) W(-1), and Tyvek 1427, Cotton Coveralls and Work Clothes all at 0.013 kPa m(2) W(-1). This wear test method improves on past methods using the progressive protocol to determine evaporative resistance by including the effects of movement, air motion and wetness on the estimate of clothing insulation. The pattern of evaporative resistance is the same as that for critical WBGTs and a linear relationship between apparent total evaporative resistance and WBGT clothing adjustment factor is suggested. With the large sample size, a good estimate of sample variance associated with progressive method can be made, where the standard error is 0.0044 kPa m(2) W(-1) with a 95% confidence interval of 0.0040-0.0050 kPa m(2) W(-1).

Bronchial artery embolization is a well accepted and widely used technique in the management of massive haemoptysis in cystic fibrosis (CF). It can be a complex procedure requiring a deep knowledge of the bronchial artery anatomy including the possible bronchial anastomoses. We report a case of complex vascular anatomy of the left bronchial artery with multiple anastomoses with the ipsilateral subclavian artery as cause of non-attempted embolization.

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