Direct Optical Measurement of Intraoperative Myocardial Oxygenation During Congenital Heart Surgery

Abstract

This study demonstrates use of novel technology to measure cellular oxygenation during corrective congenital heart surgery. Cellular oxygenation was measured using a custom-designed optical probe placed on the free wall of the right ventricle. Cellular oxygenation, determined from myoglobin saturation, was calculated using multiwavelength analysis. Timing of bypass, aortic cross-clamp, infusion of cardioplegic solution, and length of intensive care unit (ICU) stay were recorded. Baseline cellular oxygenation was approximately 50% just before aortic cross-clamp and decreased to approximately 20% during cardioplegia. Cellular oxygenation remained low throughout cardioplegia and returned toward baseline after bypass. In four cases, cellular oxygenation did not return as quickly to baseline as in the other three cases. Among the four patients demonstrating slow recovery, the average ICU length of stay was 2.25 days compared with an average stay of 1.33 days for those patients exhibiting rapid cellular oxygenation recovery (p = 0.06). The slow recovery group had an average cross-clamp time of 40.1 ± 28.4 minutes, compared with 26.0 ± 8.5 minutes for the fast recovery group (p = 0.34). This study demonstrates for the first time that myocyte cellular oxygenation can be measured intraoperatively during cardiac surgery. Measurement of cellular oxygenation may be useful for improving myocardial preservation techniques.