OBJECTIVE: To analyze the impact of acute renal failure (ARF) on the evolution of infants undergoing cardiac surgery. METHODS: We assessed 15 infants undergoing cardiac surgery who developed (ARF). Their demographic, clinical and surgical data, and evolution were analyzed. RESULTS: Their mean age was 4.4±4.0 months (8 days to 24 months). Twelve infants were males, and 4 patients already had ARF at surgery. The primary cause of ARF was immediate acute cardiac dysfunction in 10 infants, cardiac dysfunction associated with sepsis in 2 infants, and isolated sepsis in 3 infants. All children depended on mechanical ventilation during their postoperative period, 14 infants used vasoactive drugs, and 11 had an infectious process associated with ARF. Thirteen infants required dialytic treatment. Eleven infants developed oluguric ARF, and all had to undergo peritoneal dialysis; of the 4 patients with non-oliguric, 2 required dialysis, the main indication being hypervolemia. Of these 13 dialyzed infants, 4 died in the first 24 hours because of the severity of the underlying cardiac disease (mean urea level of 49±20 mg/dl). The mortality rate for the entire group was 60% , and it was higher among the patients with oliguria ARF (73% vs 25%, p<0.001). The cause of death was acute cardiac dysfunction in 6 infants (early type-1ARF) and sepsis in the 3 remaining infants (late type-2 ARF). CONCLUSION: The mortality rate of ARF associated with cardiac surgery in infants was hight, being higher among children with oliguria; peritoneal dialysis was indicated due to clinically uncontrolled hypervolemia and not to the uremic hypercatabolic state.

OBJETIVO: Variação sazonal na pressão arterial foi relatada em estudos com indivíduos hipertensos e normotensos. Porém, a influência de variação sazonal na pressão sangüínea de pacientes em hemodiálise não foi relatada. Neste estudo nós investigamos a variação sazonal da pressão sangüínea no Brasil, um país tropical, em pacientes em programa de hemodiálise. TIPO DE ESTUDO: Estudo clínico prospectivo. LOCAL: Unidade de diálise de um centro médico terciário (Hospital de ensino da Faculdade de Medicina da Universidade de São Paulo <FONT FACE="Symbol">¾</font> São Paulo ). PACIENTES: 16 pacientes com insuficiência renal crônica em programa de hemodiálise. VARIÁVEIS: Registro da pressão arterial, peso corpóreo e temperatura ambiente durante seis sessões de hemodiálise, realizadas em 13 dias durante as quatro estações do ano. RESULTADOS: A pressão arterial diastólica foi menor no verão que no outono e inverno (95 ± 8 vs 107 ± 10 e 101 ± 10 mmHg, respectivamente; p <0,05). O mesmo foi observado para a pressão arterial média (116 ± 8 vs 130 ± 11 e 124 ± 9 mmHg, respectivamente; P <0,01). Por outro lado, a temperatura ambiental foi mais alta no verão que no outono e inverno (23.0 ± 1.6 vs 19.5 ± 3.0 e 15.8 ± 1.9 ºC, respectivamente; p <0,01). CONCLUSÕES: Nós concluímos que para pacientes com insuficiência renal crônica a pressão sangüínea tem uma variação sazonal com pressões mais altas no outono e inverno que no verão. Sendo assim, estudos adicionais são necessários para elucidar o impacto desta observação no ajuste do tratamento anti-hipertensivo e na morbidade e mortalidade de pacientes em programa de diálise.

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.