Infrared image monitoring of local anesthetic poisoning in rats / Monitorização por imagem infravermelha da intoxicação por anestésico local em ratos

Abstract Background and objectives: To evaluate the thermographic predictive value of local anesthetic poisoning in rats that indicates the early recognition of thermal signs of intoxication and enable the immediate start of advanced life support. Methods: Wistar rats underwent intraperitoneal injection of saline and ropivacaine; they were allocated into pairs, and experiments performed at baseline and experimental times. For thermography, central and peripheral compartment were analyzed, checking the maximum and average differences of temperatures between groups. Thermographic and clinical observations were performed for each experiment, and the times in which the signs of intoxication occurred were recorded. In the thermal analysis, the thermograms corresponding to the times of interest were sought and relevant data sheets extracted for statistical analysis. Results: Basal and experimental: the display of the thermal images at times was possible. It was possible to calculate the heat transfer rate in all cases. At baseline it was possible to see the physiology of microcirculation, characterized by thermal distribution in the craniocaudal direction. It was possible to visualize the pathophysiological changes or thermal dysautonomias caused by intoxication before clinical signs occur, characterized by areas of hyper-radiation, translating autonomic nervous system pathophysiological disorders. In animals poisoned by ropivacaine, there was no statistically significant difference in heat transfer rate at the experimental time. Conclusions: The maximum temperature, medium temperature, and heat transfer rate were different from the statistical point of view between groups at the experimental time, thus confirming the systemic thermographic predictive value.

Resumo Justificativa e objetivos: Estudar o valor preditivo termográfico na intoxicação por anestésico local em ratos que efetue o reconhecimento precoce dos sinais térmicos de intoxicação e possibilite o início imediato do suporte avançado de vida. Método: Ratos Wistar foram submetidos à injeção intraperitoneal de soro fisiológico e ropivacaína, alocados aos pares, e foram feitos experimentos em tempos basal e experimental. Para o estudo termodinâmico foram analisados o compartimento central e o periférico, verificaram-se as diferenças das temperaturas máximas e médias entre os grupos. Foram feitas observações clínicas e termográficas para cada experimento e anotados os tempos em que os sinais de intoxicação ocorriam. Foram buscados na análise termográfica os termogramas correspondentes aos tempos de interesse e extraídas as planilhas de dados correspondentes, para análise estatística. Resultados: Foi possível a visibilização das imagens térmicas nos momentos basal e experimental. Foi possível calcular a taxa de transferência de calor em todos os casos. No momento basal foi possível observar a fisiologia da microcirculação, caracterizada por distribuição térmica no sentido craniocaudal. Foi possível visibilizar as alterações fisiopatológicas ou disautonomias térmicas causadas pela intoxicação antes que os sinais clínicos ocorressem, caracterizadas por áreas de hiperradiação e traduziram perturbações fisiopatológicas do Sistema Nervoso Autônomo. Nos animais intoxicados por ropivacaína houve diferença estatisticamente significativa na taxa de transferência de calor no momento experimental. Conclusões: Constatou-se que a temperatura máxima, a temperatura média e a taxa de transferência de calor foram diferentes do ponto de vista estatístico entre os grupos no momento experimental, o que corrobora o valor preditivo termográfico sistêmico.

Falla renal aguda por fenazopiridina / Acute renal failure caused by phenazopyridine

A 27 years old woman was admitted due to abdominal cramps, jaundice and oligoanuria, starting 48 hours after eating Chinese food. Hepatic biochemical tests, abdominal ultrasound and retrograde pyelography were normal. The urine was intensely orange colored and microscopic analysis was normal. The serum creatinine and urea nitrogen on admission were 4.59 and 42.5 mg/dl and rose to 13.5 and 72.4 mg/dl, respectively, at the 6th hospital day. Oliguria lasted only 48 hours. Dialysis was not used, since the patient was in good general condition and uremic symptoms were absent. On the 7th day, azotemia began to subside and at the 14th day, serum creatinine was 1.0 mg/dl. Before hospital discharge, she confessed the ingestion of 2.000 mg of phenazopyridine, during a nervous breakdown, aiming to sleep deeply. Remarkable was the persistence of the orange color of her urine during several days and the dissociation between the rate of increase of serum creatinine with respect to urea nitrogen. This is an unusual case of acute renal failure caused by an overdose of a drug, commonly prescribed for urinary tract infections.