Background

Elevated arterial–central venous carbon dioxide partial pressure difference (AVCO₂) may be an important marker to predict tissue and organ hypoperfusion in adults. We analyzed the hemodynamic data of infants with congenital heart disease who underwent corrective repair with cardiopulmonary bypass (CPB) to identify whether AVCO₂ has clinical significance in early postoperative tissue hypoperfusion, occurrence of complications, and clinical outcomes.

Methods

Infants with clinical conditions of hypoperfusion, without volume responsiveness and with ineffective initial treatment, within 3 h of cardiac surgery were enrolled in this study. A pulse contour cardiac output catheter was used to monitor the cardiac index (CI). Eight measurements of arterial blood gas and central venous blood gas were taken within 42 h after surgery. Clinical data of all patients were recorded.

Results

A total of 69 children were enrolled in this study. Arteriovenous oxygen difference, AVCO₂, lactic acid level, and vasoactive inotropic score in the hypoperfusion group (oxygen supply/oxygen consumption ratio [DO₂/VO₂] of ≤ 2) were significantly higher than those in the non-hypoperfusion group (DO₂/VO₂ > 2), while the CI in the hypoperfusion group was significantly lower than that in the non-hypoperfusion group. The cutoff value of AVCO₂ to predict DO₂/VO₂ ≤ 2 was 12.3 within 42 h of surgery with area under the curve of 0.84. High AVCO₂ is more likely to be associated with some complications and prolonged mechanical ventilation and length of stay in the intensive care unit.

Conclusion

Elevated AVCO₂ within 42 h of CPB in infants is associated with tissue and organ hypoperfusion and incidence of complications. Persistent or repeated increase in AVCO₂ indicates poor prognosis.