Veno-arterial CO2 difference and cardiac index in children after cardiac surgery.

Veno-arterial CO2 difference has been considered as a marker of low cardiac output. This study aimed to evaluate the correlation between veno-arterial CO2 difference and cardiac index estimated by MostCareTM in children after cardiac surgery and its association with other indirect perfusion parameters and the complex clinical course (vasoactive inotropic score above 15 or length of stay above 5 days).Data from 40 patients and 127 arterial and venous CO2 measurements for gap calculation taken 0-5 days postoperatively were available. The median (range) veno-arterial CO2 difference value was 9 (1-25 mmHg). The correlation between veno-arterial CO2 difference and cardiac index was not significant (r: -0.16, p = 0.08). However, there was a significant correlation between veno-arterial CO2 difference and vasoactive inotropic score (r: 0.21, p = 0.02), systolic arterial pressure (r: -0.43, p = 0.0001), dP/dtMAX (r: 0.26, p = 0.004), and arterio-venous O2 difference (r: 0.63, p = 0.0001). Systolic arterial pressure (OR 0.95, 95% CI 0.90-0.99), dP/dtMAX (OR 0.00, 95% CI 0.00-0.06), lactates (OR 1.87, 95% CI 1.21-3.31), and veno-arterial CO2 difference (OR 1.13, 95% CI 1.01-1.35) showed a significant univariate association with the complex clinical course. In conclusion, veno-arterial CO2 difference did not correlate with cardiac index estimated by MostCareTM in our cohort of post-cardiosurgical children, but it identified patients with the complex clinical course, especially when combined with other direct and indirect variables of perfusion.

Vancomycin prophylaxis in paediatric patients following cardiac surgery: a retrospective evaluation of trough levels and associated variables.

OBJECTIVES: Therapeutic drug monitoring during vancomycin administration is recommended. However, little information is available in case of paediatric vancomycin prophylaxis. The aim of this study was to analyse vancomycin trough levels on postoperative day (POD) 2 and 3 after paediatric cardio-surgery to assess the clinical predictors and outcomes associated with vancomycin concentrations and to evaluate whether adjustments are effective to target optimal levels. METHODS: A retrospective study was conducted in paediatric patients receiving vancomycin prophylaxis after elective cardio-surgery. Adjustments were made if levels between 20 and 30 (halving subsequent dose) or ˃30 mg/l (dose withheld) were found. RESULTS: Vancomycin doses of the 100 examined children (3.7-6.4 years) were 12.8 (2.5), 9.4 (5.4) and 9.7 (4.5) mg/kg, on POD1, 2 and 3, respectively (P = 0.0001). The 200 vancomycin trough levels decreased from 16.9 (11.4) on POD2 to 14.6 (8.5) on POD3 (P = 0.003). Overall, 66 troughs were sub-target, 68 reached the optimal target and 66 were supra-target. On POD2 and 3, 32 and 27 dose adjustments were required, leading to a reduced number of patients with supra-target troughs. Neonates showed a higher number of supra-target levels with respect to non-neonatal patients on both POD2 (P = 0.003) and 3 (P = 0.0001). At multivariable regression analysis, vancomycin levels showed independent association with weight and creatinine levels on both POD2 and 3. Vancomycin levels correlated with ventilation days (P = 0.31, P = 0.039), but not with methicillin-resistant Staphylococcus aureus positivity (P = 0.69). CONCLUSIONS: Vancomycin prophylaxis in paediatric cardio-surgery requires strict therapeutic drug monitoring and several dosage adjustments. Supra-target troughs are frequent and neonatal age, weight and creatinine levels significantly affect vancomycin concentrations.