[Effects of pulmonary surfactant in treatment of acute lung injury after cardiac surgery in infants].

OBJECTIVE: Acute lung injury is a severe complication after cardiac surgery performed with cardiopulmonary bypass in infant patients. Pulmonary surfactant has been successfully used in treating neonatal respiratory distress syndrome for many years. This study focused on exploring the clinical efficacy of exogenous pulmonary surfactant in treating infant patients with acute lung injury after cardiac surgery with the use of extracorporeal circulation. METHOD: Twenty-three infants with ventricular septal defect (VSD) were enrolled in the study. None of the patients needed oxygen treatment nor ventilation before heart surgery. VSD repair operation was done under cardiopulmonary bypass, and acute lung injury was found postoperatively. Ten infant patients in the treatment group were given pulmonary surfactant by tracheal instillation during mechanical ventilating postoperatively. Thirteen patients in control group were randomly selected in the same period in hospital, and acute lung injury was diagnosed without pulmonary surfactant treatment after cardiopulmonary bypass. Blood samples were obtained from all the patients, and blood gas analysis was performed every 6 hours. Demographics (body weigh, age, gender, VSD diameter) and clinical characteristics (CPB time, oxygenation index, mean airway pressure, pH and PCO2) of all the patients were collected, and statistical analysis was done to compare the data between treatment and control group. RESULT: In the first 24 hours after heart surgery, compared with the control group, a more increased oxygenation index (from 89.36 ± 12.69 to 285 ± 16.51) was observed in treatment group, and it was from 93.71 ± 11.82 to 133 ± 19.62 in the control group. There was a significant difference in oxygenation index between the two groups (P < 0.05). At the same time, the MAP (from 17.5 ± 3.18 to 10.4 ± 3.37) of the patients in comparison with the control group (from 18.2 ± 2.63 to 13.8 ± 2.55), a more significantly decreased MAP was observed in the treatment group (P < 0.05). There was no significant difference in pH and PCO2 between the two groups. The ventilation time in cardiac care unit was shorter in treatment group (17.43 ± 9.12) h compared with the control group [(30.97 ± 14.85) h, P < 0.05]. ICU stay time of treatment group (3.90 ± 1.34) d was shorter than that of control group [(6.18 ± 1.90) d, P < 0.05].Two infants of the control group died, but none in treatment group died. CONCLUSION: In this study, a satisfactory curative effect was observed for the treatment of acute lung injury with PS intratracheal instillation after heart surgery under cardiopulmonary bypass in infant patients. It can reduce the duration of mechanical ventilation and cardiac care unit stay and improve prognosis. In addition, this study was a pilot study and the limited sample size was probably the cause of insufficient statistical power. Further study of larger scale is needed.

[Extracorporeal membrane oxygenation for severe acute respiratory and heart failure in a child with severe pneumonia].

OBJECTIVE: To report clinical application of Extracorporeal membrane oxygenation for severe acute respiratory and heart failure in a child with severe pneumonia. METHOD: A seven-year old male patient with severe pneumonia complicated with heart and lung function failure was admitted to PICU in 28th of December, 2008.Veno-artery access was set up via euthyphoria cannulation in operative incision. Blood was drained from the right atrium through a cannula introduced via femoral veins, and returned via femoral artery. The inter-surface of the ECMO equipment system was completely coated with heparin-coating technique. Anticoagulation was maintained with heparin to keep the activated clotting time (ACT) between 150 and 200 seconds and heparin usage dose was 10 U/(kg.h), mean blood flow was 1/2-2/3 of 80-120 ml/(kg.min) during ECMO assistant period. During ECMO, ventilator settings were gradually reduced to allow lung rest, i.e. peak inspiratory pressure less than 25 cm H2O (1 cm H2O=0.098 kPa), end expiratory pressure 8-10 cm H2O, rate 10-15 breaths per minute and FiO2 30%-40%. RESULTS: In management of ECMO, the incipient blood flow was set at 0.8 L/min, the radio of oxygen and blood flow was 1:1, FiO2 60%. After ten minutes of ECMO working, the blood oxygen saturation of radial artery increased from 40 mm Hg (1 mm Hg=0.133 kPa) to 177 mm Hg, Lac decreased from 3.5 mmol/L to 2.8 mmol/L. Four hours later, blood gas analysis of radial artery showed PaO2 202 mm Hg, PCO2 44 mm Hg, Lac 1.5 mmol/L, blood flow was set at 0.6 L/min, FiO2 60%, PaO2 kept above 150 mm Hg. 96 hours after ECMO supporting, the blood flow was set at 0.4 L/min [20 ml/(kg.min)], the results of blood gas analysis of radial artery was PaO2 190 mm Hg, PaCO2 36 mm Hg, SaO2 100%, Lac 0.9 mmol/L, then the child weaned off successfully from ECMO. Two days later, the child was successfully extubated. After two weeks treatment, the patient was discharged. The main complication associated with extracorporeal membrane oxygenation were bleeding. CONCLUSION: ECMO is an effective mechanical assistant therapy method for severe pulmonary and cardiac failure in a child.

Tissue-engineered heart valve on acellular aortic valve scaffold: in-vivo study.

The feasibility of constructing a tissue-engineered heart valve on an acellular porcine aortic valve leaflet was evaluated. A detergent and enzymatic extraction process was developed to remove the cellular components from porcine aortic valves. The acellular valve leaflets were seeded for 7 days in vitro with cells from canine arterial wall and endothelial cells. The constructs were implanted into the lumens of 6 canine abdominal aortas to assess the reconstruction of the valve leaflets. It was found that all cellular components had been removed from the porcine aortic valves. The valve leaflets were completely reconstructed at the end of the 10th week in vivo. Scanning electron microscopy showed that the valve leaflets were partially covered with endothelial cells. It was concluded that porcine aortic valves can be decellularized by the detergent and enzymatic extraction process and it is feasible to construct a tissue-engineered heart valve in vivo on an acellular valve scaffold.