Clinical applications of photoplethysmography in paediatric intensive care.

OBJECTIVE: The photoplethysmographic wave is displayed by most pulse oximeters. It may be used as a non-invasive alternative to invasive arterial blood pressure trace analysis for continuous haemodynamic monitoring in selected situations. PATIENTS AND SETTING: Four cardiac patients treated in a tertiary neonatal-paediatric intensive care unit. MEASUREMENTS: Simultaneous monitoring of the photoplethysmographic wave, ECG, and invasive blood pressure. RESULTS AND CONCLUSIONS: Photoplethysmography allows for monitoring pulse rate in patients with (possible) heart rate/pulse rate dissociation (pacemaker dependency, pulsatile ventricular assist device); monitoring sudden changes in heart beat volume, which are unrelated to respiration (pulseless electrical activity, pulsus alternans); and monitoring respiratory-dependent fluctuations of the plethysmographic wave (heart failure, hypovolaemia, asthma, upper airway obstruction, pericardial effusion). Deterioration, slowly evolving over time, may be detected by this method.

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.

Antithrombin activity in children with chylothorax.

OBJECTIVE: To determine whether increased antithrombin loss is present in children with chylothorax after cardiac surgery. METHODS: Plasma and pleural effusion samples of children with chylous and non-chylous pleural effusion were assayed for antithrombin activity. RESULTS: Ten children with chylothorax and five children with non-chylous pleural effusion were investigated. There was statistically significant increase in mean antithrombin activity in chylous samples (32.2+/-11.4%) compared to non-chylous samples (14.4+/-13.9%), and significant decrease in plasma of children with chylothorax (44.6+/-15.4%) compared to children with non-chylous pleural effusion (69.9+/-22.4%). Seven of 10 children with chylous and none of the children without chylous developed thrombosis (p<0.007). CONCLUSIONS: Increased loss of antithrombin is present in children with chylothorax, potentially predisposing these children to an increased risk of thrombosis. Repeated antithrombin substitution should be considered in critically ill children with chylothorax.

Does critical incident reporting contribute to medication error prevention?

UNLABELLED: Medication-related critical incidents (CIs) comprise harmful and potentially harmful events. The aim of CI monitoring is quality improvement through system changes. In a prospective survey, we analysed our drug-related CIs of the year 2001 with an emphasis on how they contributed to system changes. A voluntary, anonymous, non-punitive CI reporting was used. The study was performed in a multidisciplinary, 23-bed, neonatal-paediatric intensive care unit (ICU). CI severity was graded: minor (no interventions required), moderate (requiring routine therapy, available outside the ICU), major (need for therapeutic interventions specific to the ICU). There were 284 drug-related CIs, 76% (95% confidence interval 71%-81%) of minor, 19% of moderate and 5% of major severity. A total of 24 CIs were potentially life threatening (if not detected). Some 27% of CIs were intercepted, 17% before preparation and 10% before administration of the drug to the patient. There was a negative correlation between median delay (from CI to detection) and mean severity of the different drug classes involved (P = 0.027). As to the impact on quality, 46 CIs were followed by system changes and 63% (95% confidence interval 49%-77%) of these CIs were of minor severity. Examples of system changes are: double checking for potentially harmful drugs, standardised prescription form and contact to the national drug control agency regarding misleading drug labels. CONCLUSION: most of the system changes were based on minor critical incidents which were often detected only after a longer period of time. This shows the value of our "low-threshold" critical incident monitoring. Repeated checks along the drug delivery process (prescription, preparation, administration) are an important means to reduce adverse drug events.

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.

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 Children's 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.