Hemoglobin substitute and cardiopulmonary bypass

The effects of diaspirin crosslinked hemoglobin (DCLHb, Baxter Health Care Corp., Round Lake, IL) on oxygen exchange in the setting of cardiopulmonary bypass (CPB) are unknown. Six calves (71.2 +/- 1.3 kg) were connected to C PB by jugular Venous and carotid arterial cannulation for 5 hours. Each 1 h our period included 45 min of partial CPB (mean flow rate of 50 ml/kg per m in) followed by 15 min without CPB, at the end of which 500 mi of blood wer e substituted for with either 500 mi of hydroxyethyl starch (Haes; n = 3) o r 500 mi of DCLHb (n = 3). A total of 2 liters of blood was, thus, exchange d (28 ml/kg of blood substitute). Values are expressed as mean a 1 SD. Anal ysis of variance for repeated measurements was used. The cardiac output (CO ) values at 1 h, 3 h, and 5 h were in the Haes group: 5.7 +/- 2, 6.7 +/- 2. 5, and 7.7 +/- 2.5L/min, and in the DCLHb group: 5.7 +/- 0.6, 4 +/- 1, and 4.7 +/- 1.2 L/min, respectively. The arteriovenous oxygen content differenc e (Ca-Cvo(2)) values at 1 h, 3 h, and 5 h were in the Haes group: 4.6 +/- 1 , 3.3 +/- 1.5, and 3.5 +/- 1.5 ml/dl, and in the DCLHb group: 4.9 +/- 0.6, 7.4 +/- 0.7, and 6.6 +/- 0.6 ml/dl, respectively. The oxygen consumption (V o(2)) values at 1 h, 3 h, and 5 h were in the Haes group: 244 +/- 29, 198 /- 58, and 249 +/- 42 ml/min, and in the DCLHb group: 273 +/- 28, 296 +/- 7 5, and 306 +/- 65 ml/min, respectively. CO and Ca-Cvo(2) showed a significa nt difference (p < 0.01), whereas Vo(2) did not (p = 0.52). In the DCLHb gr oup of this CPB animal model, the cardiac output is lower and the arteriove nous oxygen content difference higher than in the Haes group, allowing for preserved oxygen consumption.