Dextran 70 versus donor plasma as colloid in open-heart surgery under extreme haemodilution

Abstract

Dextran 70 and donor plasma were compared as colloid in the priming solution during heart-lung perfusion in open-heart surgery. The patients underwent surgery for coronary artery or aortic valve disease. One group of nine patients had plasma in the priming solution, while ten patients received dextran 70. Prior to perfusion the patients in the dextran group received monovalent hapten to prevent anaphylactic reactions towards dextran. During the perfusion the same level of haemodilution was established in both groups; the haematocrit values fell from about 39 vol. per cent before perfusion to about 19 vol. per cent after 45 min of perfusion. Eighteen hours postoperatively, the haematocrit had increased to about 35 vol. per cent. The mean concentrations of total serum protein in preoperative samples from the plasma and dextran group were 66.0 g/1 and 66.3 g/1, respectively, and fell to 42.6 g/1 and 28.3 g/1 in samples taken after 45 min of perfusion. The serum-protein concentration in the dextran group remained significantly lower than that of the plasma group throughout the postoperative period. A similar pattern was seen for the albumin concentration. Preoperatively the mean values of the colloid osmotic pressure of plasma were 24.2 mmHg and 25.5 mmHg in the plasma and dextran group, respectively. Corresponding figures 45 min after start of perfusion were 13.9 mmHg and 16.9 mmHg, respectively, significantly higher in the dextran group than in the plasma group. The colloid osmotic pressure exerted by dextran was about 9 mmHg during heart-lung perfusion and about 4 mmHg 18 h later. It is concluded that dextran may replace donor plasma as colloid during heart-lung perfusion in open-heart surgery. Furthermore, the use of dextran may be advantageous compared to plasma, since it allows adjustment of the colloid osmotic pressure over a wider range than does donor plasma.

Key Words:

• colloid osmotic pressure
• dextran
• haemodilution
• heart-lung perfusion
• open-heart surgery
• plasma
• transcapillary fluid balance