Perfusion
-
Reduction of priming volumes of the cardiopulmonary bypass (CPB) circuit in neonatal cardiac surgery to decrease haemodilution and blood transfusion requirements can be achieved with the use of neonatal low prime oxygenators and smaller diameter tubing. We have further reduced our prime volume with the use of a custom-designed arm allowing for remote positioning of a double-headed roller pump. ⋯ Results showed a 29% decrease in priming volume and a 58% reduction in blood utilization during CPB. This reduction in priming volume is clinically significant as it lowers the ratio of priming volume to patient blood volume and reduces homologous blood requirements.
-
Femoral venous cannulae (17-28 French) were tested to compare flows obtained by their placement in a simulated inferior vena cava (IVC) or right atrium (RA) and by varying drainage pressures using gravity siphon drainage or a centrifugal pump in the venous line. The circuit consisted of conventional tubing and equipment including a segment of thin-walled latex tubing to simulate the IVC connected to a flexible reservoir to simulate the RA. The test fluid was a 40% glycerin solution. ⋯ When negative pressure was applied with the centrifugal pump, flow increased 10% and 18% (IVC and RA positions, respectively) compared to gravity siphon drainage conditions. There also was a tendency for flow to plateau or cease when the centrifugal pump was used at higher levels of negative pressure or when larger cannulae were used. We conclude: (1) position of smaller cannulae in the RA yield better flows than when the cannulae are larger and placed in the IVC; (2) smaller-sized cannulae are capable of achieving higher flows when the centrifugal pump is used; (3) cannulae must be properly positioned to achieve maximum flow; (4) the centrifugal pump will augment flow, but should be regulated to avoid extreme negative pressures; and (5) cannula design has no demonstrable effect on flow.
-
Conventional cardiopulmonary bypass (CPB) in neonates results in increased transfusion requirements and hemodilution. There has been little advancement in CPB for the neonatal population. There is evidence that increased priming volumes and blood product transfusion enhances inflammatory response to CPB and increases myocardial and pulmonary dysfunction. ⋯ Among all parameters tested, except for blood requirement and hematocrit post-CPB, there were no significant differences between the two circuits. VAVD makes asanguineous prime in neonates feasible. When used in this study to miniaturize a conventional-CPB circuit, VAVD with a reconfigured neonatal CPB console and circuit resulted in no detrimental effects, and allowed for markedly decreased priming volumes and blood transfusion requirements.
-
Randomized Controlled Trial Clinical Trial
Effect of low-dose methyl prednisolone on serum cytokine levels following extracorporeal circulation.
The systemic inflammatory response to cardiopulmonary bypass (CPB) is associated with increased production of cytokines. This systemic inflammatory response characterized by the activation of interleukin-6 (IL-6) and interleukin-8 (IL-8) during and after CPB is well documented. A prospective, randomized, double-blind study was performed so as to understand the effects of low-dose methyl prednisolone sodium succinate (MPSS) on the circulating levels of serum cytokines and clinical outcome. ⋯ There was significant elevation of WBC levels at T2 and T3 in both groups without notable difference between the groups (p < 0.05). This study has shown that low-dose MPSS suppresses CPB-induced inflammatory response. Further clinical studies (on larger and higher risk groups) may reveal more information on relations between morbidity and cytokine levels which may have some predictive value on clinical outcome following CPB.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of three plasma expanders used as priming fluids in cardiopulmonary bypass patients.
Ten per cent low molecular weight hydroxyethyl starch is a plasma substitute only recently used as priming solution in an extracorporeal circuit, in contrast to human albumin and gelatin. To evaluate the effect of priming solutions on haemodynamics and colloid osmotic pressure, we studied 36 patients elected for cardiopulmonary bypass (CPB). They were randomly assigned to 2.5% hydroxyethyl starch, 3% gelatin or 4% human albumin priming solution. ⋯ Due to the extended half-life and the additional postoperative colloid administration, the hydroxyethyl starch group had a higher colloid osmotic pressure in the postoperative phase. We conclude that, next to human albumin, 2.5% hydroxyethyl starch is a safe CPB priming solution additive and is effective as plasma substitute. Its somewhat longer half-life requires adaptation of the routine protocol for transfusion of colloids and blood products.