The value of end-tidal carbon dioxide monitoring during systemic-to-pulmonary artery shunt insertion in cyanotic children

Objective: To investigate the relationship between end-tidal carbon dioxide levels and augmentation of pulmonary blood flow achieved by insertion of systemic-pulmonary shunts. Design: Prospective clinical study. Settings: University hospital. Participants: Nineteen cyanotic children with tetralogy of Fallot. Interventions: Modified Blalock-Taussig shunt operations were performed on the left side in 14 patients and on the right side in 5 patients. Measurements and Main Results: End-tidal carbon dioxide tension was recorded, and an arterial blood gas sample was obtained simultaneously after thoracotomy (TO) and after completion of systemic-pulmonary shunt (T1). End-tidal carbon dioxide tension was significantly higher (p < 0.01), and arterial to end-tidal carbon dioxide tension difference was significantly lower (p < 0.01) at T1 when compared with TO. The increase in end-tidal carbon dioxide showed a statistically significant correlation with the response of arterial oxygen saturation (r = 0.61, p < 0.01). The fall in arterial to end-tidal carbon dioxide tension difference correlated inversely with the change of oxygen saturation (r=0.81, p < 0.0001). Conclusion: It is concluded that end-tidal carbon dioxide tension alterations offer an alternative intraoperative tool to monitor pulmonary blood flow during modified Blalock-Taussig shunt procedures. (C) 2004 Elsevier Inc. All rights reserved.