Hémofiltration continue veinoveineuse après chirurgie cardiaque Etude rétrospective chez seize patients en défaillance multiviscérale

Abstract

As intermittent haemodialysis in critically ill patients is often associated with circulatory instability and hypotension, pumped continuous veno-venous haemofiltration (CVVH) has been proposed as an alternative. This technique was used postoperatively in 16 cardiac surgery patients with cardiogenic shock (cardiac index < 2.21 · min −1 · m −2), anuria and multiple organ failure. A mean haemofiltration rate of 0.5 to 11 · h −1 was used. Average length of treatment was 57 ± 38 h. Two patients were improved and weaned from CVVH after 96 and 144 h respectively. The other fourteen died. A mean 200 ± 50 ml of liquid were removed every hour. The technique was well tolerated by the cardiovascular system. The sytolic arterial pressure, heart rate and cardiac index remained unchanged. Body weight had decreased by 3 ± 1 kg after 48 h of use. Similarly, serum creatinine concentration was lowered from 337 ± 32 mmol · 1 −1 to 252 ± 27 mmol · 1 −1 (p < 0.001). At that time, urea and creatinine clearances were 18 ± 2 ml · min −1, and 15 ± 1 ml · min −1 respectively. After 24 h of CVVH, both serum sodium and potassium concentrations had been decreased, from 148 ± 3 mmol · 1 −1 to 142 ± 2 mmol · 1 −1 (p < 0.001), and from 5.7 ± 0.3 to 4.2 ± 0.15 mmol · 1 −1 (p < 0.001) respectively. In addition, pH increased significantly from 7.13 ± 0.1 to 7.30 ± 0.04 (p < 0.001). These results were comparable with these of other authors regarding safety and efficiency of CVVH. The low patient survival rate (12.5 %) was due to the severity of cardiac impairment. It seems established that continuous extracorporeal purification is preferable to sequential methods in post bypass low cardiac output states. CVVH is simple and rapidly set-up in the intensive care unit. However, any beneficial effect it may have on the mortality rate depends mainly on the severity and reversibility of the patient's cardiac failure.