Overview of Cardiopulmonary Bypass Techniques and the Incidence of Postoperative Complications in Pediatric Patients Undergoing Complex Pulmonary Artery Reconstruction

Abstract

Cardiopulmonary bypass (CPB) is routinely used for performing congenital heart operations. While most congenital heart operations can be performed with bypass times under 2 hours, complex pulmonary artery reconstructions require longer periods of CPB to facilitate the surgical repair. This article is intended to summarize the surgical and perfusion techniques utilized in patients undergoing complex pulmonary artery reconstructions at our institution. The initial portion of this manuscript provides an in-depth description of the surgical techniques employed for pulmonary artery reconstructions. This information is important in order to understand why prolonged CPB is a necessary requirement. The manuscript then provides a detailed description of the perfusion techniques and the modifications to the CPB circuit. Finally, the manuscript provides a summary of data from a clinical study evaluating the application of these techniques in 100 consecutive children undergoing complex pulmonary artery reconstruction. The data from this study demonstrated that there was a poor correlation between duration of CPB and both the number of postoperative complications and hospital length of stay. Major adverse cardiac events occurred in 11 (11%) patients with one hospital mortality. These results suggest that prolonged CPB does not predispose to adverse outcomes in this select population of patients.

Keywords: cardiopulmonary bypass; congenital heart disease; congenital heart surgery; major aortopulmonary collateral arteries.; outcomes; pulmonary arteries.

Figure 1.

Diagram of the CPB circuit for unifocalization or pulmonary artery reconstruction procedures. The circuit size is upsized in anticipation of the need for longer periods of CPB (from Margetson et al. (14), reproduced with permission).

Figure 2.

Diagram of the flow study modification to the CPB circuit. An additional pump-head is required that will be dedicated to perfusing the reconstructed pulmonary artery bed following unifocalization.

Figure 3.

Diagram of the collateral flow study modification to the CPB circuit. This modification permits the measurement of the residual collateral flow once the MAPCAs have been ligated (from Mainwaring et al. (28), reproduced with permission).

Figure 4.

Histogram demonstrating the CPB times for the patient cohort. The median CPB time was 473 minutes (from Mainwaring et al. (25), reproduced with permission).

Figure 5.

Histogram demonstrating the number of complications sustained per patient. The median number of complications was four with a range of 0–19 (from Mainwaring et al. (25), reproduced with permission).

Figure 6.

Scatter plot demonstrating: (A) the relationship between total number of complications (y-axis) and the length of hospital stay (x-axis). Linear regression analysis demonstrated an R-squared = 0.64. (B) Total number of complications (y-axis) and CPB time (x-axis). Linear regression analysis demonstrated an R-squared = 0.002. (C) The length of hospital stay (y-axis) and CPB time (x-axis). Linear regression analysis demonstrated an R-squared = 0.005 (from Mainwaring et al. (25), reproduced with permission).

Figure 7.

Graph demonstrating the prevalence of MACE in patients with CPB times of 5–6 hours, 7–8 hours, and >9 hours (from Mainwaring et al. (25), reproduced with permission).