648 Oesophageal Doppler Monitor Detects Changes in Cardiac Index During Pacemaker Testing in Children After Cardiac Surgery

Abstract

Background: The Cardio QP™ Oesophageal Doppler Monitor measures the velocity time integral of the blood flow in the descending aorta Based on nomogramms of the aortic cross sectional area of a paediatric population cardiac index is calculated and displayed on the monitor. Objective: Evaluation of the capability of the Oesophageal Doppler Monitor to detect slight changes in cardiac output as they occur during desynchronizing ventricular pacing (VVI) in children after cardiac surgery. Patients: 11 infants (6 female, 5 male) after corrective cardiac surgery of congenital heart defects Median age: 49 months (20-15 months), median weight: 44 kg (34- 78 kg). Interventions: After baseline measurements of cardiac output, we performed 3 steps of each 5 minutes: 1 ventricular- pacing, 2 baseline II, 3 atrial pacing in order to exclude effects of higher cardiac frequency We measured the effects on hemodynamic and respiratory parameters as well as on cardiac output. Measurements and Main Results: VVI pacing leads to a significant decrease in arterial blood pressure and central venous saturation Cardiac output parameters measured by the oesophageal Doppler monitor showed a significant decrease in stroke volume (SV) from 49 ± 22 to 42 ± 21 (p= 0005) and cardiac Index (CI) (26 ± 11 to 21 ± 08) (p= 0009) from baseline during ventricular stimulation The changes in Cardiac output and hemodynamic parameters during atrial stimulation did not show a significant difference from baseline. Conclusion: The oesophageal Doppler monitor may be reliable in the detection of slight changes in cardiac output.