Impact of Phlebotomy Volume Knowledge on Provider Laboratory Ordering and Transfusion Practices in the Pediatric Cardiac ICU.

OBJECTIVES: Phlebotomy can account for significant blood loss in post-surgical pediatric cardiac patients. We investigated the effectiveness of a phlebotomy volume display in the electronic medical record (EMR) to decrease laboratory sampling and blood transfusions. Cost analysis was performed. DESIGN: This is a prospective interrupted time series quality improvement study. Cross-sectional surveys were administered to medical personnel pre- and post-intervention. SETTING: The study was conducted in a 19-bed cardiac ICU (CICU) at a Children's hospital. PATIENTS: One hundred nine post-surgical pediatric cardiac patients weighing 10 kg or less with an ICU stay of 30 days or less were included. INTERVENTIONS: We implemented a phlebotomy volume display in the intake and output section of the EMR along with a calculated maximal phlebotomy volume display based on 3% of patient total blood volume as a reference. MEASUREMENTS AND MAIN RESULTS: Providers poorly estimated phlebotomy volume regardless of role, practice setting, or years in practice. Only 12% of providers reported the availability of laboratory sampling volume. After implementation of the phlebotomy display, there was a reduction in mean laboratories drawn per patient per day from 9.5 to 2.5 ( p = 0.005) and single electrolytes draw per patient over the CICU stay from 6.1 to 1.6 ( p = 0.016). After implementation of the reference display, mean phlebotomy volume per patient over the CICU stay decreased from 30.9 to 14.4 mL ( p = 0.038). Blood transfusion volume did not decrease. CICU length of stay, intubation time, number of reintubations, and infections rates did not increase. Nearly all CICU personnel supported the use of the display. The financial cost of laboratory studies per patient has a downward trend and decreased for hemoglobin studies and electrolytes per patient after the intervention. CONCLUSIONS: Providers may not readily have access to phlebotomy volume requirements for laboratories, and most estimate phlebotomy volumes inaccurately. A well-designed phlebotomy display in the EMR can reduce laboratory sampling and associated costs in the pediatric CICU without an increase in adverse patient outcomes.

Anti-Xa levels in critically ill children receiving enoxaparin for venothromboembolism prophylaxis.

Venothrombolism (VTE) prophylaxis is increasingly utilized in pediatric intensive care units (PICUs). Enoxaparin, a low-molecular weight heparin, is frequently used for this purpose. Enoxaparin can also be used for therapeutic anticoagulation in cases of known thrombus. In such cases, monitoring involves obtaining serum anti- Xa levels with a target value of 0.5-1 units/mL. No monitoring recommendations currently exist for enoxaparin when intended for pediatric VTE prophylaxis. We hypothesize that a clinically important number of patients on VTE prophylaxis with enoxaparin have serum anti-Xa levels consistent with values targeted for therapeutic anticoagulation. We found that over 20% of patients on VTE prophylaxis with enoxaparin had serum anti-Xa levels consistent with true therapeutic anticoagulation (anti-Xa level 0.5-1 units/mL) during their enoxaparin course and 5% achieved values of supratherapeutic anticoagulation (anti-Xa level >1 units/mL). Serum anti-Xa level did not correlate with once versus twice daily dosing, body mass index (BMI), or creatinine level. Blood urea nitrogen (BUN) was found to have a positive odds ratio for an anti-Xa level ≥ 0.5 units/mL. We believe that this incidence of unintended therapeutic anticoagulation indicates a clinically significant number and therefore routine anti-Xa evaluation while on VTE prophylaxis is warranted within our population.

The low specificity of low voltage bridges associating atrioventricular nodal reentry in pediatric patients.

PURPOSE: Patients with atrioventricular nodal reentry tachycardia (AVNRT) often are managed successfully by ablation of the slow pathway with success rates reported as high as 99%. Low voltage bridges (LVBs) have been demonstrated to be helpful in guiding AVNRT ablation. Patients may present to the electrophysiology lab without evidence of inducible arrhythmia. In these scenarios, the demonstration of LVBs may be diagnostic and guide catheter ablation treatment. The purpose of our study was to prospectively investigate the specificity of LVBs as a diagnostic marker of AVNRT. METHODS: Patients aged < 19 years with narrow complex tachycardia prospectively underwent electrophysiology study with intention to perform catheter ablation. In each patient, the primary objective was the collection of right atrial voltage data that was then used to identify LVBs. RESULTS: Twenty-four patients were included after exclusion criteria were applied. Final diagnosis was 11 AVNRT and 13 non-AVNRT (nAVNRT). LVBs were identified in 11/11 AVNRT patients and 9/13 non-AVNRT patients (p = 0.09). CONCLUSIONS: LVBs are not specific to patients with AVNRT and cannot solely be used for diagnosis. However, in patients with documented AVNRT, the LVB can be used to identify the location of the slow pathway.

A Review of Surgical Atrioventricular Block with Emphasis in Patients with Single Ventricle Physiology.

We perceived an increased incidence of surgical atrioventricular (AV) block in patients with single ventricle physiology undergoing two ventricle rehabilitation for hypoplastic left heart syndrome compared to the overall incidence of surgical AV block for our institution. Retrospective investigation of our center's data revealed a statistically significant increase in the incidence of surgical AV block in the single ventricle population and two ventricle rehabilitation population compared to the two ventricle population. Here we review the literature with respect to historic definitions, incidence, risk factors, pre- and post-op management, current indications for pacemaker placement and added cost and comorbidity associated with surgical AV block. We then offer possible strategies for decreasing the incidence of surgical AV block within both the single and two ventricle populations.

Clinical Implications of a Multivariate Stratification Model for the Estimation of Prognosis in Ventricular Septal Defect.

OBJECTIVES: To derive and validate a multivariate stratification model for prediction of survival free from intervention (SFFI) in ventricular septal defect (VSD). A secondary aim is for this model to serve as proof of concept for derivation of a more general congenital heart disease prognostic model, of which the VSD model will be the first component. STUDY DESIGN: For 12 years, 2334 subjects with congenital heart disease were prospectively and consecutively enrolled. Of these, 675 had VSD and form the derivation cohort. One hundred seven other subjects with VSD followed in another practice formed the validation cohort. The derivation cohort was serially stratified based on clinical and demographic features correlating with SFFI. RESULTS: Six strata were defined, the most favorable predicting nearly 100% SFFI at 10 years, and the least favorable, a high likelihood of event within weeks. Strata with best SFFI had many subjects with nearly normal physiology, muscular VSD location, or prior intervention. In the validation cohort, the relation between predicted and actual SFFI at 6 months, 1 year, 2 years, and 5 years follow-up had areas under the receiver operating characteristic curves 0.800 or greater. CONCLUSIONS: A prediction model for SFFI in VSD has been derived and validated. It has potential for clinical application to the benefit of patients and families, medical trainees, and practicing physicians.

Hybrid procedure as treatment for large obstructive left ventricular rhabdomyoma.

We present one of the first reported cases of a neonate with a prenatal diagnosis of large left ventricular rhabdomyoma obstructing the outflow tract that underwent a hybrid procedure with stenting of the patent duct arteriosus and bilateral pulmonary artery banding.