[Extracorporeal membrane oxygenation treatment of a neonate with severe low cardiac output syndrome following open heart surgery].

Objective: To summarize the experience of extracorporeal membrane oxygenation (ECMO) to rescue a neonate with severe low cardiac output syndrome following open heart surgery.
Methods: The patient was a male, 2 d, 2.8 kg, G3P2 full-term neonate with gestational age 40 weeks, born by Cesarean-section with Apgar score of 10 at 1 min. He was admitted due to severe dyspnea with oxygen desaturation and heart murmur on the second day after birth. Physical examination showed clear consciousness, cyanosis, dyspnea, RR 70 bpm and a grade II/6 heart murmur. Bp was 56/45 mm Hg (1 mm Hg = 0.133 kPa) and SpO2 around 65%. Blood WBC 13.1 x 10(9)/L, N 46.1%, Hb 238 g/L, Plt 283 x 10(9)/L, CRP < 1 mg/L. Echocardiographic findings: TGA + ASD + PDA with left ventricular ejection fraction (LVEF) of 60%. After supportive care and prostaglandin E1 (5 ng/kg/min) treatment, his condition became stable with SpO2 85 - 90%. On the 6(th) day of life, the baby underwent an arterial switch procedure + ASD closing and PDA ligation. The time of aorta clamp was 72 mins. The cool 4:1 blood cardioplegia was given for 2 times during aortal clamp. Ultrafiltration was used. The internal and external volumes were almost equal and the electrolytes and blood gas and hematocrit (36%) were normal during extracorporeal bypass. Due to a failure (severe low cardiac output) to wean from cardiopulmonary bypass (263 min) with acidosis (lactate 8.8 mmol/L), low blood pressure (< 39/30 mm Hg), increased LAP (> 20 mmHg), bloody phlegm, decreased urine output [< 1 ml/(kg.h)], a V-A ECMO was used for cardio-pulmonary support. ECMO setup: Medtronic pediatric ECMO package (CB2503R1), carmeda membrane oxygenator and centrifugal pump (bio-console 560) were chosen. Direct cannulation of the ascending aorta (Edward FEM008A) and right atrium (TF018090) was performed using techniques that were standard for cardiopulmanory bypass. The ECMO system was primed with 400 ml blood, 5% CaCl(2)1g, 5% sodium bicarbonate 1.5 g, 20% mannitol 2 g, albumin 10 g, and heparin 5 mg. The blood was re-circulated until the temperature was 37 degrees C and blood gases and the electrolytes were in normal range. The patient was weaned from bypass and connected to V-A ECMO. Management of ECMO: the blood flow was set at 150 - 200 ml/kg/min. Venous saturation (SvO2) was maintained at the desired level (75%) by increasing and decreasing extracorporeal blood flow. Systemic blood pressure was maintained at 76/55 - 80/59 mm Hg by adjusting blood volume. Hemoglobin was maintained between 120 - 130 g/L. Platelet count was maintained at > 75,000/mm3 and ACT was maintained at 120 - 190 s. The mechanical ventilation was reduced to lung rest settings (FiO2 35%, RR 10 bpm, PIP 16 cm H(2)O, PEEP 5 cm H2O) to prevent alveolar collapse. Inotropic drug dosages were kept at a low level.
Results: The patient was successfully weaned from ECMO following 87 hours treatment. LVEF on day 1, 2 and 3 following ECMO were 20%, 34% and 43% respectively. The circulation was stable after weaning from ECMO with Bp 75/55 mm Hg, HR 160 bpm and LAP 11 mm Hg under inotropic drug suppor with epinephrine [(0.2 microg/(kg.min)], dopamine [(8 microg/(kg.min)], milrinone [(0.56 microg/(kg.min)]. The blood gases after 1 h off-ECMO showed: pH 7.39, PaO2 104 mm Hg, PaCO2 45 mm Hg, lactate 3.8 mmol/L, Hct 35%, K(+) 3.8 mmol/L, Ca(++) 1.31 mmol/L. The serum lactate was normal after 24 h off-ECMO. On day 22 off-ECMO, the baby was successfully extubated and weaned from conventional ventilator. On day 58, the patient was discharged. Serial ultrasound imaging studies revealed no cerebral infarction or intracranial hemorrhage during and after ECMO. At the time of hospital discharge, the patient demonstrated clear consciousness with good activity, normal function of heart, lung, liver and kidney. However, more subtle morbidities, such as behavior problems, learning disabilities should be observed ria long term follow-up. The main ECMO complications were pulmonary hemorrhage, bleeding on the sternal wound, tamponade, hemolysis and hyperbilirubinemia.
Conclusion: ECMO is an effective option of cardio-pulmonary support for neonate with low cardiac output syndrome following open heart surgery.