Gerhard Trittenwein

Early postoperative prediction of cerebral damage after pediatric cardiac surgery

BACKGROUND Cerebral damage is a serious complication of pediatric cardiac surgery. Early prediction of actual risk can be useful in counseling of parents, and in early diagnosis and rehabilitation therapy. Also, if all children at risk could be identified therapeutic strategies to limit perioperative cerebral damage might be developed. The aim of this study is to create a mathematical model to predict risk of neurologic sequelae within 24 hours after surgery using simple and readily available clinical measurements. METHODS The hospital records of 534 children after cardiac surgery were reviewed. Variables examined were age at operation, diagnosis, use of cardiopulmonary bypass, arterial and central venous oxygen saturation, serum glucose, lactate and creatine kinase, mean arterial pressure, and body temperature. The endpoint for each study patient was the occurrence or lack of occurrence of seizures, movement or developmental disorders, cerebral hemorrhage, infarction, hydrocephalus, or marked cerebral atrophy. Univariate and multivariate regression analyses were used to evaluate the predictive power of the investigated factors as well as to create a predictive model. RESULTS In 6.26% of children symptoms of cerebral damage were found. Significant risk factors were age at surgery, more complex malformations, metabolic acidosis, and increased lactate (odds ratio: age, 0.882/yr [0.772-1.008]; complex malformations, 10.32 [1.32-80.28]; arterial pH more than 7.35 to 0.4 [0.18-0.89]; lactate -1.018 per mg/dL [1.006-1.03]). CONCLUSIONS It is possible to quantify the risk of appearance of symptoms of cerebral damage after cardiac surgery within 24 hours using simple and readily available clinical measurements.

Predictors of mortality at initiation of peritoneal dialysis in children after cardiac surgery

BACKGROUND The development of renal dysfunction in the postoperative course of cardiac surgery is still associated with high mortality in pediatric patients. In particular for small infants peritoneal dialysis offers a secure and useful treatment option. The aim of the present study was to investigate if routinely used laboratory and clinical variables could help predict mortality at initiation of peritoneal dialysis. METHODS We performed a retrospective chart analysis of pediatric intensive care unit patients with renal dysfunction who were treated with peritoneal dialysis after cardiac surgery between 1993 and 2001 and analyzed variables obtained 3 hours or less before starting peritoneal dialysis. RESULTS Results are documented as means and standard errors. A total of 1141 children underwent a cardiac operation on cardiopulmonary bypass. Sixty-two children (5.4%) were treated with peritoneal dialysis. Mortality was 40.3% (37 survivors, 25 nonsurvivors). The pH in survivors was 7.35 (0.01); in nonsurvivors it was 7.23 (0.03; p = 0.0037). Base excess in survivors was -1.37 mmol/L (0.61); in nonsurvivors it was -7.17 mmol/L (1.49; p = 0.0026). Lactate in survivors was 4.5 mmol/L (0.60); in nonsurvivors it was 10.5 mmol/L (1.78; p = 0.0089). Positive inspiratory pressure in survivors was 24.6 cm H(2)O (0.78); in nonsurvivors it was 28.9 cm H(2)O (1.08; p = 0.0274). Tidal volume per kilogram bodyweight in survivors was 11.0 mL/kg (0.48); in nonsurvivors it was 8.7 mL/kg (0.50; p = 0.0493). CONCLUSIONS We conclude from our data that the consideration of pH, base excess, lactate, positive inspiratory pressure, and tidal volume per kilogram bodyweight help predict mortality at initiation of peritoneal dialysis. We were able to observe significant differences between survivors and nonsurvivors using these variables.

Surfactant therapy in infants and children: three years experience in a pediatric intensive care unit.

Despite the established success of surfactant application in neonates, the use of surfactant in older children is still a matter of discussion. We hypothesized that surfactant application in children with acute respiratory distress syndrome (ARDS) secondary to a pulmonary or systemic disease or after cardiac surgery improves pulmonary function. We also asked whether repeated treatment could further improve pulmonary function. To answer these questions, we measured oxygenation index (OI) and hypoxemia score after the first and after a second application of surfactant (50–100 mg/kg body wt) at least 24 h later. We enrolled 19 children (older than 4 weeks) for a retrospective chart review study, and six of them underwent cardiac surgery. Demographic data were extracted. OI and hypoxemia score were estimated before and 2 and 24 h after surfactant application. Lung injury score was calculated before and 24 h after surfactant application. Outcome measures included survival, duration of mechanical ventilation, and pediatric ICU and hospital stay. The median patient age was 9.0 (quarter percentile 3.7/25) months. The median weight was 8.4 (4.1/11.5) kg. The median lung injury score before the first surfactant application was 2.3 (2.3/2.6). Hospital duration and pediatric ICU stay for all patients was 31.0 (20.0/49.5) days and 27.0 (15.5/32.5) days, respectively. The duration of mechanical ventilation was 24.0 (18.5/31.0) days. The overall mortality was 53%. Twenty-four hours after the first surfactant application, pulmonary function significantly improved. The median OI was 14 (5.5/26) before and 7 (4.5/14.5) 24 h after surfactant application (P = 0.027). The hypoxemia score was 91.7 (69.9/154.2) before and 148.4 (99.2/167.6) 24 h after surfactant application (P = 0.0026). Seven children received a second application, which did not further improve pulmonary function. The lung injury score was not influenced by either surfactant application. We conclude that a single surfactant application improves pulmonary function in children with ARDS. A second application of surfactant showed no further benefit. Outcome was not affected in our study population.

Severe respiratory failure following charcoal application in a toddler

Charcoal has been commonly used for enteral detoxication with few adverse effects. In toddlers charcoal can often be simply applied via a gastric tube. Regurgitation and aspiration is considered a rare event. We report the case of a 19-month-old boy who suffered endobronchial charcoal contamination followed by acute airway obstruction and severe respiratory failure despite a commonly used tube placement verification technique. Immediate intubation, tracheal suctioning, intravenous bronchodilators, and high frequency oscillatory ventilation (HFOV) were used to control hypercarbia and hypoxia. Eventually charcoal removal by bronchoscopy was successful. Chest X-ray investigation did not reflect the true amount of charcoal deposited endobronchially at any time. We conclude that gastric tube application of charcoal in children carries a risk of aspiration. This may lead to life-threatening respiratory failure with the need to provide artificial ventilation and bronchial lavage.

Preoperative ECMO in congenital cyanotic heart disease using the AREC system

BACKGROUND In cyanotic congenital heart disease, oxygen delivery is impaired either by reduced pulmonary perfusion or by limited entry of oxygenated blood into the systemic circulation. Additional impairment of oxygen delivery (eg, in pulmonary hypertension) leads to hypoxic cerebral damage. Preoperative extracorporeal membrane oxygenation enables oxygenation in otherwise untreatable cases. METHODS In 3 neonates suffering from cyanotic congenital heart disease (1 with tricuspid atresia and 2 with transposition of the great arteries) with arterial desaturation despite application of prostaglandins, balloon atrioseptostomy, and eventually inhaled nitric oxide during intermittent positive-pressure ventilation with an inspired oxygen fraction of 1, oxygenation could only be established by means of preoperative extracorporeal membrane oxygenation. We used a venovenous single-lumen cannula tidal-flow extracorporeal membrane oxygenation system described by Chevalier and associates that has previously been used for extracorporeal lung support. In this system, called AREC (assistence respiratoire extra-corporelle), alternating clamps and a nonocclusive roller pump were used. RESULTS All 3 survived. CONCLUSIONS We conclude that the AREC system enables sufficient preoperative oxygenation in patients with cyanotic congenital heart disease and hypoxia in spite of all conventional therapeutic means. This provides a stable preoperative condition for elective palliation or correction.

Impact of extracorporeal membrane oxygenation modality on cytokine release during rescue from infant hypoxia.

The treatment of acute respiratory failure in infants by means of extracorporeal membrane oxygenation (ECMO) is thought to be associated with a treatment-related inflammatory reaction, which may deteriorate the underlying disease process. The aim of this study was to compare the venoarterial (VA) and venovenous (VV) modality of ECMO with regard to their pulmonary and serological cytokine release during rescue from acute hypoxia. The inflammatory response was measured in piglets undergoing hypoxic ventilation with a gas mixture of 92% N2 and 8% O2, which were then rescued through VA- (n = 5) or VV-ECMO (n = 5). The effect of cannulation and anesthesia on the inflammatory response was deducted from regularly ventilated control animals (n = 5). The concentrations of the proinflammatory interleukins (IL)-1&bgr; and IL-8 increased in the bronchoalveolar lavage fluid of all groups over a study period of 5 h but were significantly higher (P < 0.05) during VA-ECMO treatment, whereas the anti-inflammatory IL-10 concentrations were significantly higher in the bronchoalveolar lavage fluid of VV-treated animals (P < 0.001). No statistical difference between groups was found in the serum concentrations of cytokines. We conclude that in this animal model rescue from hypoxia by means of the VA modality of ECMO leads to a more pronounced inflammatory reaction of the lung than when applying the VV modality.

Life threatening cardiopulmonary failure in an infant following protamine reversal of heparin after cardiopulmonary bypass

Life threatening cardiopulmonary failure following protamine reversal of heparin after cardiopulmonary bypass (CPB) was reported to occur in adults but rarely in children. Atrial septal defect closure was performed in a 6‐week‐old infant erroneously suspected to suffer from right atrial thrombosis in addition. Protamine administration after CPB led to critical pulmonary hypertension and severe haemorrhagic pulmonary oedema resulting in severe hypoxia. Inhaled nitric oxide, together with high frequency oscillation ventilation supplemented by intravenous prostacycline, enabled complete recovery of cardiopulmonary and neurological function. Life threatening cardiovascular compromise after intravenous protamine can occur even in young infants which then require challenging paediatric critical care.

Monitoring of cerebral oxygen saturation with a jugular bulb catheter after near-drowning and respiratory failure

ZusammenfassungWir berichten über die kontinuierliche Überwachung der zerebralen Sauerstoffsättigung bei einem 18 Monate alten Mädchens nach Beinahe-Ertrinken und akuter respiratorischer Insuffizienz. Die Messungen, die mit Hilfe eines retrograden fiberoptischen Jugulariskatheter durchgeführt wurden, zeigten im Gegensatz zu den zentral-venösen und arteriellen Werten eine akut bedrohliche zerebrale Sauerstoffuntersättigung an. Nachdem konventionelle Therapiemaßnahmen zur Verbesserung der zerebralen Sauerstoffsättigung fehlschlugen konnte diese erst durch den Einsatz der extrakorporalen veno-venösen Membranoxygenierung (vv ECMO) erreicht werden. Das Mädchen wurde nach 7 Tagen extubiert und ohne neurologische Defekte nach 25 Tagen nach Hause entlassen. In Fällen von Beinahe-Ertrinken ist die kontinuierliche Messung der zerebralen Sauerstoffsättigung mittels eines retrograden fiberoptischen Jugulariskatheters ein wichtiges diagnostisches Instrument, um eine kritische Sauerstoffversorgung des Gehirns frühzeitig zu erfassen.SummaryWe report on monitoring oxygen saturation with a jugular bulb fiber-optical catheter in an 18-month-old girl after fresh water near-drowning followed by acute respiratory failure. The first measured cerebral oxygen saturation was 22% despite normal values for arterial and central venous oxygen saturation. After conventional therapy had failed to improve cerebral oxygen saturation, we started veno-venous extracorporeal membrane oxygenation. Normal levels of cerebral oxygen saturation were achieved after six hours. The girl was extubated after seven days and discharged after twenty-five days in good general condition and without obvious evidence of neurological damage. We believe that in this case of near-drowning, monitoring cerebral oxygen saturation with a jugular bulb catheter was important for surveillance of cerebral hypoxia.