The effect of mild therapeutic hypothermia on renal function after cardiopulmonary resuscitation in men

Background: Mild therapeutic hypothermia (MTH) improves neurological outcome in patients after cardiac arrest. From animal and human studies it appears that hypothermia impairs renal function. The aim of this study was to examine the effects of MTH on renal function in humans. Methods: Patients were participants recruited in one of the centres of the hypothermia after cardiac arrest-multicenter trial. We measured serum creatinine and creatinine clearance ( C Cr) within 24 h of MTH, at 4 hourly intervals. Patients were followed for acute renal failure and need for renal supportive therapy for 28 days. Results: We included 60 patients (32 hypothermic, 28 normothermic). Median serum creatinine on admission was [{119 μmol/l (IQR 108–133)} {1.35 mg/dl (IQR 1.22–1.50)}] in hypothermic and [{114 μmol/l (IQR 99–131)} {1.29 mg/dl (IQR 1.12–1.48)}] in normothermic patients, and decreased to [{69 μmol/l (IQR 62–84)} {0.78 mg/dl (IQR 0.70–0.95)}] in the hypothermic group and to [{88 μmol/l (IQR 71–123)} {1.00 mg/dl (IQR 0.80–1.39)}] in the normothermic group within 24 h. C Cr was decreased on admission. Within 24 h C Cr improved to normal values in normothermic patients [1.53 ml/s (IQR 1.15–2.35) {92 ml/min (IQR 69–141)}] and remained low in hypothermic patients [0.88 ml/s (IQR 0.63–1.38) {53 ml/min (IQR 38–83)}] ( P=0.0006). No difference was found between the groups in the development of acute renal failure or the need for renal supportive therapy. Conclusion: Twenty four hours of MTH was associated with a delayed improvement in renal function. This was not reflected in the serum creatinine values, which were low in the hypothermic group. This transient impaired renal function appeared to be completely reversible within 4 weeks. Contexto: A terapêutica com hipotermia ligeira (MTH) melhora o prognóstico neurológico nos doentes após paragem cardı́aca. Dos estudos animais e humanos parece que a hipotermia afecta a função renal. O objectivo deste estudo é examinar os efeitos da MTH na função renal em humanos. Métodos: Os doentes foram recrutados de um dos centros do ensaio multicêntrico de hipotermia após paragem cardı́aca. Foi medida a creatinina sérica e a clearance da creatinina ( C Cr) durante 24 h de MTH, em intervalos de 4 horas. Os doentes foram seguidos durante 28 dias, durante os quais se observou o desenvolvimento de Insuficiência renal e a necessidade de terapêutica de suporte dialı́tico. Resultados: Foram incluı́dos no estudo 60 doentes (32 hipotermicos, 28