The effect of normobaric hypoxic exposure on coagulation as measured by thromboelastography.

INTRODUCTION: The physiological impact of hypoxia on coagulation has significant importance in the clinical setting, but it is not yet fully understood. Various static methods exist to investigate the process of coagulation, however, thromboelastography (TEG) provides a dynamic assessment of clot formation that can be quantitatively assessed. METHOD: Twenty-five participants were exposed to normobaric hypoxia (12.5% oxygen) for 8 h. Venous blood was taken from the participants directly pre- and post-hypoxic exposure, and coagulation was tested using TEG. Coagulation variables assessed included reaction time, split point, alpha angle, kinetics and maximum amplitude. RESULTS: Time taken for clot initiation, (assessed using the split point and reaction time) was significantly reduced after 8 h of hypoxic exposure. The split point reduced from a mean of 5.20 to 4.23 min (p = 0.022), whilst the reaction time reduced from 6.09 to 4.94 min (p = 0.004). Maximum amplitude, alpha angle and kinetics did not change significantly after hypoxic exposure. CONCLUSION: The results demonstrate that subacute normobaric hypoxic exposure increases the tendency for whole blood to coagulate, as demonstrated by a reduced split and reaction time using TEG.

Off-label prescribing in the treatment of dermatologic disease.

BACKGROUND: It is common practice for physicians to treat dermatologic conditions with medications that are not indicated for the specific condition being treated. These "off-label" prescriptions are often for medications that have both well accepted therapeutic value in the medical community and proven efficacy on the basis of results of clinical trials. OBJECTIVE: Our purpose was to quantify the use of off-label prescriptions for dermatologic disease by a representative sample of physicians in the United States. METHODS: Data from the 1990-1997 National Ambulatory Medical Care Survey, performed by the National Center for Health Statistics, were used to assess medications prescribed at office visits for dermatologic disease. We identified the most common diagnoses listed at office visits in which the primary and only diagnosis listed was dermatologic. For the leading 10 dermatologic conditions for which medications are indicated, we categorized each primary drug mention by indication. RESULTS: We found that the range of off-label prescribing varied from 17% to 73%, with a weighted mean (+/- SD) of 32% +/- 18%. The conditions most frequently managed with off-label prescriptions were acne rosacea (73%) and actinic keratosis (52%), whereas those with the fewest off-label prescriptions were atopic dermatitis (17%) and psoriasis (16%). The use of off-label prescriptions by dermatologists in the diseases studied ranged from 7% to 73% with a weighted mean (+/- SD) of 24% (+/- 24%), whereas the range for nondermatologists was 18% to 96% with a weighted mean (+/- SD) of 34% (+/- 18%). CONCLUSION: Off-label prescribing is common in the management of dermatologic conditions. From these data, we conclude that it is currently within the standard of care to use off-label prescriptions in the treatment of dermatologic disease.