Postoperative Heart Rate Control with Esmolol in Newborn Cardiac Surgery with Cardiopulmonary Bypass

Background: In neonates, sinus tachycardia frequently occurs after cardiac surgery despite correction of usual causes, such as stress, pain, fever, hypovolemia or anemia. Tachycardia-induced additional myocardial oxygen consumption may even deteriorate function of postoperative hearts. Beta-1-selective, short-acting β-blockers are useful to control the heart rate but data on their efficacy and safety in newborn cardiac surgery with CPB are lacking.

Method: As an institutional approach, we used a continuous esmolol infusion to optimize postoperative heart rate as >140 bpm was deemed “out-of-proportion” and unnecessary to maintain cardiac output. Patients with ECMO support were excluded from this retrospective analysis. Between 2009 and 2020, a total of 69 newborns (female/male = 30/39) after cardiac surgery with CPB were included in this study. Esmolol dosage was adopted to achieve a heart between 120 and 140 bpm. Postoperative care followed a standardized protocol. Biometric data and oximetry were recorded at start of esmolol and under “steady state” conditions. Side effects, as well as outcome data, were analyzed.

Results: Median age was 8 (IQR: 5–14) days, median body weight 3.4 (IQR: 2.9–3.7) kg. Surgery was performed for d-TGA in 32 (46%) and for repair of a hypoplastic aortic arch in 20 (29%) patients. Other diagnosis included truncus arteriosus (n = 6) and TAPVR (n = 5). Median cardiac arrest time was 98 (IQR: 37–120) minutes. Esmolol infusion was started perioperatively in 29 (42%) patients and between 2 and 18 hours in 40 (58%) children. Median initial esmolol dosage was 48 (IQR: 25–80) µg/kg/min and was increased in 36 (52%), decreased in 12 (17%), and unchanged in 21 (31%) patients. Median heart rate at postoperative admission on ICU was 159 (IQR: 149–169) bpm and decreased with esmolol to 140 (IQR: 130–147; p < 0.001) bpm. Blood pressure and amplitude, as well as pressure-rate product decreased significantly with esmolol therapy. While there was no difference in serum lactate and central venous saturation between ICU admission and esmolol therapy, AVDO2 decreased significantly with esmolol therapy (33 vs. 30%; p = 0.001). No organ failure or death occurred.

Conclusion: Currently, it is doctrine that newborns primarily depend on heart rate to generate cardiac output. Questioning this, we showed that heart rate reduction did not deteriorate hemodynamics but ergonomizes heart rate in a cohort after cardiac surgery. Whether this approach leads to an improved outcome has to be demonstrated in further studies.

Publication History

Article published online:
12 February 2022