Seasonal variation of blood pressure in maintenance hemodialysis

CONTEXT: Seasonal variation in arterial blood pressure has been reported in studies with hypertensive and normotensive subjects. However, the influence of seasonal change on blood pressure of hemodialysis patients has not been reported. OBJECTIVE: To investigate the seasonal variation of blood pressure in Brazil, a tropical country, in patients on hemodialysis. DESIGN: Prospective, cohort study. SETTING: Dialysis unit of a tertiary medical center (a teaching hospital of the University of São Paulo School of Medicine, São Paulo). PATIENTS: Sixteen patients with chronic renal failure undergoing hemodialysis. OUTCOMES: Blood pressure, body weight, and ambient temperature were evaluated during 6 hemodialysis sessions carried out on 13 days during the four seasons. RESULTS: The diastolic blood pressure was lower in summer than in fall and winter (95 ± 8 vs 107 ± 10 and 101 ± 10 mmHg, respectively; p < 0.05). The same was observed with mean blood pressure (116 ± 8 vs 130 ± 11 and 124 ± 9 mmHg, respectively; p < 0.01). On the other hand, the ambient temperature was higher in summer than in fall and winter (23.0 ± 1.6 vs 19.5 ± 3.0 and 15.8 ± 1.9 ºC, respectively; p < 0.01). CONCLUSIONS: We concluded that for patients with chronic renal failure the blood pressure has a seasonal variation with higher pressures in fall and winter than in summer. Thus, further studies are needed to elucidate the impact of this observation on the adjustment of antihypertensive treatment and on morbidity and mortality in maintenance dialysis patients

Valor do exame citológico per-operatório em neurocirurgias The value of per-operative cytological exam in neurosurgeries

INTRODUÇÃO: Mais de 90% dos resultados citológicos per-operatórios neurocirúrgicos correlacionam-se com o histopatológico. Porém, a sua real necessidade é por vezes questionada. OBJETIVO: Avaliar a necessidade do exame per-operatório tendo-se em vista a conduta neurocirúrgica imediata. MATERIAL E MÉTODOS: Revimos 130 casos de exames per-operatórios solicitados de um total de 293 procedimentos cirúrgicos para tratamento de lesões expansivas do sistema nervoso central (SNC), extra ou intra-axiais, sendo 46 biópsias estereotáxicas e 84 cirurgias abertas, realizados de 1998 a 2001. Foram realizados esfregaços, o diagnóstico foi comparado com o histopatológico, e os neurocirurgiões, questionados sobre a implicação do resultado do exame na conduta, caso a caso. RESULTADOS: O exame per-operatório foi solicitado em 44,4% do total de cirurgias, tendo sido considerado relevante para a conduta em 84% destes casos ou, nas biópsias, para avaliar a representatividade do material, o que corresponde a 37,2% do total de cirurgias realizadas no período. Excluindo-se as biópsias estereotáxicas, com indicação inquestionável, o exame foi necessário em 75%, sendo considerado desnecessário, sobretudo nas lesões extra-axiais, em geral solicitado por curiosidade do cirurgião. CONCLUSÃO: Apesar de ser um exame com acurácia demonstrada, a realização de exames per-operatórios sem utilidade para a conduta neurocirúrgica pode vir a sobrecarregar patologistas em tarefas desnecessárias. Nossos resultados demonstraram que o exame foi necessário na grande maioria dos casos, mesmo após a exclusão das biópsias estereotáxicas, sobretudo nas lesões intra-axiais, auxiliando na avaliação da demanda desses exames, por vezes excessiva, apesar de útil para treinamento e ensino.<br>BACKGROUND: More than 90% of neurosurgical per-operative cytological results have a good correlation with histopathology. However, its real necessity is sometimes questioned. OBJECTIVE: Evaluate the necessity of per-operatory exam regarding immediate neurosurgical procedure. MATERIAL AND METHODS: We reviewed 130 per-operative exams requested out of 293 surgical procedures for expansive extra or intra-axial CNS lesions, 46 stereotactic biopsies and 84 open surgeries, performed from 1998 to 2001. Smears were prepared, the results compared to the histopathological data and then the neurosurgeons were argued about its necessity and influence upon the surgical procedure, case by case. RESULTS: The per-operative exam was requested in 44.4% of the total number of surgeries performed, 84% of which were relevant for the procedure, or, in biopsies, to evaluate sample representativeness, corresponding to 37.2% of the total number of surgeries performed in that period. Once stereotactic biopsies were excluded, considering that in such cases the per-operative exam is unquestionable, the previous value dropped to 75%; the per-operative smear was considered unnecessary mainly in extra-axial lesions, usually required because of neurosurgeons' curiosity. CONCLUSION: Despite its well-known accuracy, per-operative exams performed without a real necessity for the surgical procedure could overcharge pathologists unnecessarily. Our results have shown that the exam was useful in the great majority of cases, even excluding stereotactic biopsies; they also help us evaluate the demand for per-operative exams, sometimes excessive, although important for practicing and teaching purposes