Katharina Waldvogel

Three Consecutive Outbreaks of Serratia marcescens in a Neonatal Intensive Care Unit

We investigated an outbreak of Serratia marcescens in the neonatal intensive care unit (NICU) of the University Hospital of Zurich. S. marcescens infection was detected in 4 children transferred from the NICU to the University Childrens Hospital (Zurich). All isolates showed identical banding patterns by pulsed-field gel electrophoresis (PFGE). In a prevalence survey, 11 of 20 neonates were found to be colonized. S. marcescens was isolated from bottles of liquid theophylline. Despite replacement of these bottles, S. marcescens colonization was detected in additional patients. Prospective collection of stool and gastric aspirate specimens revealed that colonization occurred in some babies within 24 hours after delivery. These isolates showed a different genotype. Cultures of milk from used milk bottles yielded S. marcescens. These isolates showed a third genotype. The method of reprocessing bottles was changed to thermal disinfection. In follow-up prevalence studies, 0 of 29 neonates were found to be colonized by S. marcescens. In summary, 3 consecutive outbreaks caused by 3 genetically unrelated clones of S. marcescens could be documented. Contaminated milk could be identified as the source of at least the third outbreak.

Early postoperative arrhythmias after cardiac operation in children

BACKGROUND Arrhythmias are a recognized complication of cardiac operations. However, little is known about the incidence, treatment, and risk factors for early postoperative arrhythmias in children after cardiac operations. METHODS Diagnosis and treatment of early postoperative arrhythmias were prospectively analyzed in an intensive care unit in 100 consecutive children with a median age of 17 months (range, 1 day to 191 months) who had undergone cardiac operation. Patients were grouped in three different categories of surgical complexity. RESULTS During a median postoperative time of 1 day (range, 0 to 15 days), 64 critical arrhythmias occurred in 48 patients. Arrhythmias consisted of sinus bradycardia in 30, atrioventricular block II to III in 7, supraventricular tachyarrhythmias in 14, and premature complexes in 13 instances. Treatment of 52 arrhythmias was successful and included pacing in 41, intravenous amiodarone in 8, body cooling in 5, overdrive pacing in 3, and electrolyte correction in 2 cases, with more than one treatment modality in 8 cases. Risk factors for arrhythmias were lower body weight (p < 0.05), longer cardiopulmonary bypass duration (p < 0.05), and a category of higher surgical complexity (p < 0.001). CONCLUSIONS Early postoperative arrhythmias occur frequently after cardiac operations in children. Sinus bradycardia, atrioventricular block II to III, and supraventricular tachyarrhythmias are the most frequent arrhythmias, which, however, can be treated effectively by means of temporary pacing, cooling, and antiarrhythmic drug therapy. Lower body weight, longer cardiopulmonary bypass duration, and a higher surgical complexity are risk factors for early postoperative arrhythmias.

Disseminated cat-scratch disease: Detection ofRochalimaea henselae in affected tissue

An immunocompetent 9-year-old boy with disseminated catscratch disease involving spleen, cervical and abdominal lymph nodes, skull, and one clavicle is reported. Antibodies toRochalimaea quintana andR. henselae were detected, at increasing, then decreasing concentration. DNA extracted from the biopsied skull lesion was amplified by polymerase chain reaction and hybridized with species-specific oligonucleotides proving the presence ofR. henselae in affected tissue. Our findings suggest thatR. henselea plays a pathogenic role in cat-scratch disease.

Congenital Prothrombotic Disorders in Children with Peripheral Venous and Arterial Thromboses

Aims: To evaluate the prevalence of congenital prothrombotic disorders in children with peripheral venous and arterial thromboses. Methods: Deficiencies in antithrombin (AT), proteins C (PC) and S (PS), and increased lipoprotein (a), and the presence of factor V (FV) G1691A, prothrombin G20210A and methylenetetrahydrofolate reductase (MTHFR) mutations were investigated. Results: Forty-eight patients (mean age, 3.4 years) were investigated. Of these patients, 23 had venous thrombosis, 22 had arterial thrombosis, and 3 had both. No patients had AT, PC or PS deficiency. FV G1691A mutation was present in 2 (7.6%) and 3 (12%) patients with venous and arterial thromboses, respectively. The prothrombin G20210A mutation was present in 1 (4%) patient with arterial thrombosis. Homozygous MTHFR C677T mutation was detected in 4 (18%) and 2 (9%) patients with venous and arterial thromboses, respectively. Increased lipoprotein (a) was present in 2 (10%) and 1 (4.5%) patients with venous and arterial thromboses, respectively. Regarding acquired risk factors, 79% of all thrombotic events were related to catheter usage. An underlying disease was present in 96% of the patients. Conclusions: Compared to acquired risk factors, congenital prothrombotic disorders are rarely present in children with peripheral venous and arterial thromboses. These results do not support general screening of children with venous and arterial thromboses for congenital prothrombotic disorders.

Impaired Chemical Coupling of Cerebral Blood Flow Is Compatible with Intact Neurological Outcome in Neonates with Perinatal Risk Factors

Early detection of pathophysiological factors associated with permanent brain damage is a major issue in neonatal medicine. The aim of our study was to evaluate the significance of the CO2 reactivity of cerebral blood flow (CBF) in neonates with perinatal risk factors. Fourteen ventilated neonates with perinatal risk factors (pathological cardiotocogramm, low cord pH, postpartal encephalopathy) were enrolled into this prospective study. The study was performed 18–123 h after birth. CBF was measured using the nonivasive intravenous 133Xe method. Two measurements were taken with a minimal PaCO2-difference of 5 mm Hg. From the two CBF values the CO2 reactivity was calculated. Outcome was evaluated 1 year after birth. The CBF values at a lower PaCO2 ranged from 6.6 to 115.2 ml/100 g brain issue/min (median = 18.2) and at a higher PaCO2 level from 7.1 to 125.7 ml/100 g brain tissue/min (median = 18.75). The calculated CO2 reactivity ranged from –9.6 to 6.6% (median 1.1%) change in CBF/mm Hg change in PaCO2. CO2 reactivity correlated with lowest pH (r2 = 0.35, p = 0.02). Two infants died, one of neonatal sepsis, the other of heart failure. Neurological outcome at the age of 1 year was normal in 11 patients, 1 had severe cerebral palsy. From the 12 surviving patients the patient with severe neurological deficit showed the highest CBF values (125.7 ml/100 g/min). Impaired chemical coupling of cerebral blood flow is compatible with intact neurological outcome in neonates with perinatal risk factors. CO2 reactivity in these newborns correlates with the lowest pH and may reflect the severity of perinatal asphyxia.

Long-term outcome of an infant resuscitated from iatrogenic potassium intoxication with a serum level of 17.7 mmol/l.

Acute potassium intoxication is a life-threatening event requiring aggressive therapy and a delay in diagnosis may be fatal. We report on the long-term outcome of a 6-week-old infant with severe iatrogenic potassium intoxication during post-operative care after cardiac surgery. The infant was admitted to the paediatric intensive care unit after correction of a truncus arteriosus. Her clinical course was complicated by excessive chylothorax, ascites and two episodes of sepsis. At the time of intoxication, she required inotropic support and external cardiac pacing due to atrio-ventricular block. On the 34th post-operative day, the infant suddenly developed severe arrhythmia. Intra-arterial blood pressure monitoring revealed circulatory arrest. Advanced cardiopulmonary resuscitation was initiated immediately with ventilation with FiO2 = 1.0, chest compressions and bolus injections of epinephrine (total 60 lg/kg). Chest compressions re-established effective circulation (mean arterial pressure >40 mm Hg), but refractory ventricular arrhythmia persisted. A chestX-ray film ruled out tension pneumothorax. Arterial blood sampling revealed a potassium level of 17.7 mmol/l. All intravenous infusions were halted. Under continued manual chest compression and ventilation, i.v. calcium chloride (total 0.23 mmol/kg), sodium bicarbonate (total 5 mmol/kg), infusion of glucose (total 0.7 g/kg) and insulin (total 2 U/kg), repeated furosemide boluses (total 2.7 mg/kg) and continuous inhalation with salbutamol (total 8 mg/kg), potassium levels gradually declined (Table 1). At a level of 8 mmol/l and 45 min after cardiac arrest, spontaneous pulse-generating cardiac rhythm returned with a mean arterial pressure of 40 mm Hg. External pacing was restarted and the patient returned to a stable circulatory status under continuing inotropic support with dopamine (20 lg/kg per min) and dobutamine (6 lg/kg per min). Shortly thereafter, the infant opened her eyes and was fully awake. Recently we have seen the girl at 4 years of age. She has achieved all developmental milestones and shows no neurological deficit except for severe iatrogenic hearing impairment. Subsequent investigations revealed that a short-term co-trimoxazole infusion had been erroneously prepared in the unit using a 15% potassium chloride solution with a total of 30 mmol potassium chloride instead of a 5% glucose solution. The company producing both the potassium chloride and the glucose solution was informed about the incident. Since then, the two vials now differ both in size and colour. There is no reported survival of patients with potassium levels exceeding 12 mmol/l [1]. Several authors have emphasised early initiation of either peritoneal or haemodialysis, stating that conventional procedures to lower serum potassium levels are not sufficient [4, 5, 6]. In this tiny infant (body weight 2.95 kg) with extensive thromboses in major venous vessels, neither peritoneal nor haemodialysis was an immediately available option. The key to the successful resuscitation of this infant was (1) the monitoring in place including arterial access [3], (2) the immediate start of conventional measures to shift potassium from the extracellular into the intracellular compartment [2] and (3) the data-guided (arterial blood analysis and blood pressure) advanced cardiac life support performed by highly skilled staff. This child possibly survived under conventional measures because the acutely infused amounts of potassium had not yet been distributed into the extravascular space, unlike the more gradual onset of potassium intoxication from enteral sources. Considering the present clinical status of this patient, the dramatic combination of potassium intoxication and post-surgical severe cardiac failure was endured with good outcome. Eur J Pediatr (2004) 163: 48–49 DOI 10.1007/s00431-003-1337-1