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Hemoglobin substitute and cardiopulmonary bypass
X M Mueller1, H T Tevaearai, D Jegger
1Clinic for Cardiovascular Surgery, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
Insights
Diaspirin crosslinked hemoglobin (DCLHb) maintained oxygen consumption during cardiopulmonary bypass (CPB) in calves. Despite lower cardiac output, DCLHb increased arteriovenous oxygen content difference, preserving oxygen delivery.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
- Hemorrhage Management
Background:
- Cardiopulmonary bypass (CPB) necessitates blood substitution, impacting oxygen transport.
- The efficacy of diaspirin crosslinked hemoglobin (DCLHb) as a blood substitute during CPB is not well-established.
Purpose of the Study:
- To investigate the effects of DCLHb on oxygen exchange during CPB in an animal model.
- To compare DCLHb with hydroxyethyl starch (Haes) in maintaining oxygen delivery and consumption.
Main Methods:
- Six calves underwent 5 hours of CPB with intermittent blood exchange.
- Blood was substituted with either Haes (control) or DCLHb (3 calves each).
- Cardiac output (CO), arteriovenous oxygen content difference (Ca-vO2), and oxygen consumption (VO2) were measured.
Main Results:
- The DCLHb group exhibited significantly lower CO (p < 0.01) but a higher Ca-vO2 (p < 0.01) compared to the Haes group.
- Oxygen consumption (VO2) remained comparable between groups (p = 0.52).
- DCLHb facilitated preserved oxygen consumption despite reduced cardiac output.
Conclusions:
- DCLHb effectively maintains oxygen consumption during CPB in this calf model.
- The mechanism involves an increased arteriovenous oxygen content difference, compensating for reduced cardiac output.
- DCLHb shows potential as a blood substitute in CPB settings.
Abstract:
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 CPB by jugular venous and carotid arterial cannulation for 5 hours. Each 1 hour period included 45 min of partial CPB (mean flow rate of 50 ml/kg per min) followed by 15 min without CPB, at the end of which 500 ml of blood were substituted for with either 500 ml of hydroxyethyl starch (Haes; n = 3) or 500 ml of DCLHb (n = 3). A total of 2 liters of blood was, thus, exchanged (28 ml/kg of blood substitute). Values are expressed as mean +/- 1 SD. Analysis 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 difference (Ca-Cvo2) 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 (Vo2) 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 +/- 75, and 306 +/- 65 ml/min, respectively. CO and Ca-Cvo2 showed a significant difference (p < 0.01), whereas Vo2 did not (p = 0.52). In the DCLHb group of this CPB animal model, the cardiac output is lower and the arteriovenous oxygen content difference higher than in the Haes group, allowing for preserved oxygen consumption.