Lung ultrasound profile after cardiopulmonary bypass in paediatric cardiac surgery: first experience in a simple cohort†

OBJECTIVES: To explore the association between lung ultrasound (LUS) and clinical variables in children undergoing cardiopulmonary bypass (CPB).

METHODS: A retrospective analysis was conducted in patients weighing <20 kg and with an Aristotle score <9, scanned with LUS on postoperative day (POD) 0, 1 and 2. We defined three LUS profiles: profile A: the prevalence of confluent B lines ("white lung"); profile B: the prevalence of B lines and profile C: the prevalence of A lines (normal lung).

RESULTS: Median (interquartile range [IRQ]) weight, age and Aristotle score were 5.6 kg [IQR 4.0-6.0], 3.2 months [IQR 3.0-7.0] and 6.75 [IQR 6.0-8.0], respectively. No profile A patients were found. At POD1, we identified statistically significant differences between profile B and C patients: CPB time was 157 [IQR138-235] vs 95 [IQR 85-183] minutes (P < 0.005); aortic clamp duration was 104 [IQR 87-142] vs 54 [IQR 49-72] minutes (P = 0.007); time of mechanical ventilation was 41.5 [IQR 31.0-56.0] vs 15 [IQR 15-24] hours (P < 0.001); and ICU length of stay was 2 [IQR 2-3] vs 4 [IQR 3-4] days (P = 0.001), respectively. No differences were found between profile B and C patients at all the other time points. No statistically significant differences were found for blood gas values, urine output and fluid balance at all time points.

CONCLUSIONS: In a small cohort of children undergoing CPB, the LUS profile on POD1 was associated with CPB time, aortic cross-clamp time and mechanical ventilation duration.