Low molecular starch versus gelatin plasma expander during CPB: does it make a difference?

BACKGROUND: Non-protein plasma expanders carry a risk of potentially severe allergic reactions. As prime for cardiopulmonary bypass, we routinely use a gelatin plasma expander. Plasma expanding during anesthesia is achieved with high molecular starch (200/0.5 kDalton) in combination with Ringer Lactate solution (RL) and in the Intensive Care Unit (ICU) with a low molecular starch (130/0.4 kDalton). We evaluated the feasibility of low molecular starch in combination with RL (group LMSRL) versus gelatin plasma expanding (group GPE) for priming CPB circuits in patients undergoing cardiac surgery in a randomized prospective trial.

METHODS: One hundred and eighty adults who underwent primary valve or coronary artery bypass graft (CABG) surgery were equally stratified into 3 series of 60 patients with the routinely used oxygenators; Capiox RX-25, CML Duo and Quadrox-D. Then they were randomised by drawing lots and allocated into the LMSRL or GPE groups. We compared hematocrit, hemoglobin, platelet count, activated clotting time (ACT), lactate and colloid osmotic pressure (COP), blood loss, transfusion need, urine production and ICU stay. In addition, we monitored the average trans-oxygenator fluid resistance (AFR) for each type of oxygenator.

RESULTS: The COP is significantly lower in the LMSRL group (20mmHg +/- 0.2 versus 18 mmHg +/- 0.2, p < 0.0001); as was the total use of plasma expanders (3846 ml +/- 98 versus 3059 ml +/- 77, p < 0.001). All other parameters were not significantly different. When comparing the observed AFR for the three types of oxygenators, a lower AFR in the LMSRL group (p < 0.02) was noted for the Capiox RX-25.

CONCLUSIONS: This study shows a lower need for plasma expanders in patients who receive only starch plasma expanders. Further, we noted a lower COP in the LMSRL group, but since the mean COP was >17 +/- 0.2 mmHg, this cannot be considered of clinical importance. In conclusion, our study result supports the use of low molecular starch as a good alternative choice for priming CPB.