Reducing Blood Testing in Pediatric Patients after Heart Surgery: Proving Sustainability

A Near Real-Time Risk Analytics Algorithm Predicts Elevated Lactate Levels in Pediatric Cardiac Critical Care Patients

BACKGROUND

Postoperative pediatric congenital heart patients are predisposed to develop low-cardiac output syndrome. Serum lactate (lactic acid [LA]) is a well-defined marker of inadequate systemic oxygen delivery.

OBJECTIVES

We hypothesized that a near real-time risk index calculated by a noninvasive predictive analytics algorithm predicts elevated LA in pediatric patients admitted to a cardiac ICU (CICU).

DERIVATION COHORT

Ten tertiary CICUs in the United States and Pakistan.

VALIDATION COHORT

Retrospective observational study performed to validate a hyperlactatemia (HLA) index using T3 platform data (Etiometry, Boston, MA) from pediatric patients less than or equal to 12 years of age admitted to CICU (n = 3,496) from January 1, 2018, to December 31, 2020. Patients lacking required data for module or LA measurements were excluded.

PREDICTION MODEL

Physiologic algorithm used to calculate an HLA index that incorporates physiologic data from patients in a CICU. The algorithm uses Bayes' theorem to interpret newly acquired data in a near real-time manner given its own previous assessment of the physiologic state of the patient.

RESULTS

A total of 58,168 LA measurements were obtained from 3,496 patients included in a validation dataset. HLA was defined as LA level greater than 4 mmol/L. Using receiver operating characteristic analysis and a complete dataset, the HLA index predicted HLA with high sensitivity and specificity (area under the curve 0.95). As the index value increased, the likelihood of having higher LA increased (p < 0.01). In the validation dataset, the relative risk of having LA greater than 4 mmol/L when the HLA index is less than 1 is 0.07 (95% CI: 0.06-0.08), and the relative risk of having LA less than 4 mmol/L when the HLA index greater than 99 is 0.13 (95% CI, 0.12-0.14).

CONCLUSIONS

These results validate the capacity of the HLA index. This novel index can provide a noninvasive prediction of elevated LA. The HLA index showed strong positive association with elevated LA levels, potentially providing bedside clinicians with an early, noninvasive warning of impaired cardiac output and oxygen delivery. Prospective studies are required to analyze the effect of this index on clinical decision-making and outcomes in pediatric population.

A point-of-care pharmacokinetic/pharmacodynamic trial in critically ill children: Study design and feasibility

Background

High-quality, efficient, pharmacokinetic (PK), pharmacodynamic (PD), and safety studies in children are needed. Point-of-care trials in adults have facilitated clinical trial participation for patients and providers, minimized the disruption of clinical workflow, and capitalized on routine data collection. The feasibility and value of point-of-care trials to study PK/PD in children are unknown, but appear promising. The Opportunistic PK/PD Trial in Critically Ill Children with Heart Disease (OPTIC) is a programmatic point-of-care approach to PK/PD trials in critically ill children that seeks to overcome barriers of traditional pediatric PK/PD studies to generate safety, efficacy, PK, and PD data across multiple medications, ages, and disease processes.

Methods

This prospective, open-label, non-randomized point-of-care trial will characterize the PK/PD and safety of multiple drugs given per routine care to critically ill children with heart disease using opportunistic and scavenged biospecimen samples and data collected from the electronic health record. OPTIC has one informed consent form with drug-specific appendices, streamlining study structure and institutional review board approval. OPTIC capitalizes on routine data collection through multiple data sources that automatically capture demographics, medications, laboratory values, vital signs, flowsheets, and other clinical data. This innovative automatic data collection minimizes the burden of data collection and facilitates trial conduct. Data will be validated across sources to ensure accuracy of dataset variables.

Discussion

OPTIC's point-of-care trial design and automated data acquisition via the electronic health record may provide a mechanism for conducting minimal risk, minimal burden, high efficiency trials and support drug development in historically understudied patient populations.

Trial registration

clinicaltrials.gov number: NCT05055830. Registered on September 24, 2021.

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.

Patient blood management in critically ill children undergoing cardiac surgery: A cohort study

OBJECTIVE

The objective of this study was to audit current patient blood management practice in children throughout cardiac surgery and paediatric intensive care unit (PICU) admission.

DESIGN

This was a prospective observational cohort study.

SETTING

This was a single-centre study in the cardiac operating room (OR) and PICU in a major tertiary children's hospital in Australia.

PATIENTS

Children undergoing corrective cardiac surgery and requiring admission to PICU for postoperative recovery were included in the study.

MEASUREMENTS AND MAIN RESULTS

Fifty-six patients and 1779 blood sampling episodes were audited over a 7-month period. The median age was 9 months (interquartile range [IQR] = 1-102), with the majority (n = 30 [54%]) younger than 12 months. The median number of blood sampling episodes per patient per day was 6.6 (IQR = 5.8-8.0) in total, with a median of 5.0 (IQR = 4.0-7.5) episodes in the OR and 5.0 (IQR = 3.4-6.2) episodes per day throughout PICU admission. The most common reason for blood tests across both OR and PICU settings was arterial blood gas analysis (total median = 86%, IQR = 79-96). The overall median blood sampling volume per kg of bodyweight, patient, and day was 0.63 mL (IQR = 0.20-1.14) in total. Median blood loss for each patient was 3.5 mL/kg per patient per day (IQR = 1.7-5.6) with negligible amounts in the OR and a median of 3.6 mL/kg (IQR = 1.7-5.7) in the PICU. The median Cell Saver® transfusion volume was 9.9 mL/kg per patient per day (IQR = 4.0-19.1) in the OR. The overall median volume of other infusion products (albumin 4%, albumin 20%, packed red blood cells) received by each patient was 20.1 mL/kg (IQR = 10.7-36.4) per day. Sampling events and blood loss were positively associated with PICU stay.

CONCLUSIONS

Patient blood management practices observed in this study largely conform to National Blood Authority guidelines. Further implementation projects and research are needed to accelerate implementation of known effective blood conservation strategies within paediatric critical care environments.