RESUMO
The objective of the study is to evaluate the viscosity of popular sclerosants and their flow hydrodynamics through a syringe/needle to further discuss Miyake's old, venous-capillary reflux theory, using additional objective data. The following sclerosing agents were tested in the study: 75% dextrose (D75%); 50% dextrose (D50%); 5% ethanolamine oleate (Etha5%); 0.5% laureth-9 (Aet0.5%) and 0.1% sodium tetradecyl sulphate (STS0.1%). Using 5 mL syringes and 27G needles, the resulting pressures and flows for each sclerosant agent were measured. To do this, a three-way stopcock was connected between the syringe and the needle so that an arm of the stopcock could be used to measure injection pressures with a digital monitor in 1 mmHg increments. Two trials were performed: in trial 1, the syringe was attached to a Samtronic 680 infusion pump and in trial 2, the solutions were injected manually. The observed sclerosant viscosities were as follows: D75%: 0.28 Poise; D50%: 0.12 Poise; Etha5%: 0.10 Poise; Aet0.5%: 0.07 Poise; and STS0.1%: 0.04 Poise. In trial 1 (constant flow), it was observed that D75%, which had the highest viscosity of the sclerosants tested, had the highest pressure readings. In trial 2 (constant pressure), the flow obtained with the D75% solution was lower than the flow of the other solutions. In conclusion, based on the rabbit study theory, vessel size and sclerosant viscosity and strength, not extravasation, play a role in causing ulceration from injection sclerotherapy. As a result, they all affect the potential of venous-capillary reflux being caused by sclerotherapy injection and, thus, the risk of postsclerotherapeutic cutaneous ulceration.
Assuntos
Modelos Biológicos , Soluções Esclerosantes/efeitos adversos , Escleroterapia/efeitos adversos , Úlcera Cutânea , Animais , Pressão , Coelhos , Soluções Esclerosantes/farmacologia , Escleroterapia/métodos , Úlcera Cutânea/induzido quimicamente , Úlcera Cutânea/patologia , Úlcera Cutânea/fisiopatologia , ViscosidadeRESUMO
BACKGROUND: Although lasers and intense pulsed light sources have improved the capability of injuring veins without affecting the overlying skin, work is needed to improve the procedure. OBJECTIVE: To create a method for predicting skin reaction to pulsed light. METHODS: Twenty patients were divided into four groups according to skin type (I-IV). An industrial thermometer equipped with a laser-aiming system was adapted to the intense pulsed light source handpiece. Patients received shots of increasing intensity while the skin temperature was measured. RESULTS: Fluence and temperature data were analyzed by logistic regression to evaluate possible injury. The stepwise method selected skin type and temperature variation as predictors of skin injury. Logistic curves indicated the maximum temperature variation tolerable for each skin type. More pigmented skin types tolerated less temperature increase. CONCLUSION: Skin type can predict cutaneous reaction to intense pulsed light through measurements of temperature variation. This method may help achieve successful selective photothermolysis.
Assuntos
Fototerapia , Fenômenos Fisiológicos da Pele/efeitos da radiação , Pele/efeitos da radiação , Feminino , Humanos , Modelos Logísticos , Valores de Referência , Temperatura , Coxa da PernaRESUMO
The profile of 247 patients with erythroderma during a 23 year period from January, 1962 through March, 1985, with a follow-up period ranging from 1 to 26 years were analysed. The patients presented with diffuse erythema, scaling and pruritus of more than 2 months' duration, and the age ranged from 16 to 60 years. Psoriasis was the most frequent underlying disease with an estimated frequency of 44.9%, the reaction to the use of drugs appeared in 7.3% of total cases and association with reticulosis showed a frequency of 4.1%. The cause of the erythroderma could not be determined in 29.2% of the cases. Six differences in terms of underlying diseases were not observed. One or more skin biopsies along with clinical findings were diagnostic or suggestive of the underlying disease in 63.6% of the cases. Repeated skin biopsies are recommended as the best method for etiologic diagnosis of erythroderma. At P = 0.05 significance level, masculine/feminine ratio of 2:1 was found. The question arises whether causal agent of erythroderma may not be somehow related to different exposure by sex to environmental antigens.