Anest. intenziv. Med. 2009;20(3):143-148

Regional cooling of blood in the extracorporeal circuit: New way of anticoagulation during CRRTIntensive Care Medicine - Original Paper

Kroužecký Aleš¹, Sýkora Roman¹, Chvojka Jiří¹, Karvunidis Thomas¹, Raděj Jaroslav¹, Novák Ivan¹, Růžička Jiří², Beneš Jiří², Petránková Zuzana², Bolek Lukáš², Matějovič Martin^1,*

¹ JIP, I. interní klinika, Fakultní nemocnice Plzeň a Univerzita Karlova, Lékařská fakulta v Plzni

² Ústav biofyziky, Univerzita Karlova, Lékařská fakulta v Plzni

Objective:
To test the hypothesis that cooling of blood in the extracorporeal circuit of continuous veno-venous hemofiltration (CVVH) enables to realize the procedure without the need of anticoagulation.

Design:
Experimental animal study.

Methods:
We developed the device for selective cooling of extracorporeal circuit (20 °C) allowing blood rewarming (38 °C) just before returning into the body. 12 anesthetized and ventilated pigs were randomized to receive either 6 hrs of CVVH with application of this device (COOL; n = 6) or without it (CONTR; n = 6). Before the procedure and in 15., 60., 180., 360. minute after starting hemofiltration variables related to: 1) circuit patency (time to clotting [TC], number of alarm-triggered pump stopping [AS], venous and transmembranous circuit pressures [VP, TMP]); 2) coagulation status in the extracorporeal circuit (thrombin-antithrombin complexes [TAT_circ], thromboelastography [TEG]) and 3) animal status (hemodynamics, hemolysis, biochemistry) were assessed.

Results:
The patency of all circuits treated with selective cooling was well maintained within the observation period. By contrast, 5 of 6 sessions were prematurely clotted in the untreated group. As a result, the number of AS was significantly higher in the CONTR group. In-circuit thrombus generation in CONTR group was associated with a markedly increasing TAT_circ. TEG performed at 180.minute of the procedure revealed a tendency to a prolonged initial clotting time and a significant decrease in clotting rate of in-circuit blood in the COOL group. No signs of repeated cooling/rewarming-induced hemolysis were observed in animals treated with "hypothermic circuit" CVVH.

Conclusion:
In this porcine model, regional extracorporeal blood cooling proved effective in preventing in-circuit clotting without the need to use any other anticoagulant.

Keywords: renal replacement therapy; anticoagulation; hypothermia; hemofiltration; cooling; critically ill

Received: February 18, 2009; Accepted: March 20, 2009; Published: June 1, 2009  Show citation