David Wensley

Comparison of two red-cell transfusion strategies after pediatric cardiac surgery: a subgroup analysis.

Objective: To determine the impact of a restrictive vs. a liberal transfusion strategy on new or progressive multiple organ dysfunction syndrome in children post cardiac surgery. The optimal transfusion threshold after cardiac surgery in children is unknown. Design: Randomized, controlled trial. Setting: Tertiary pediatric intensive care units. Patients: Participants are a subgroup of pediatric patients post cardiac surgery from the TRIPICU (Transfusion Requirements in Pediatric Intensive Care Units) study. Exclusion criteria specific to the cardiac surgery subgroup included: age <28 days and patients remaining cyanotic. Intervention: Critically ill children with a hemoglobin ≤95 g/L within 7 days of pediatric intensive care unit admission were randomized to receive prestorage leukocyte-reduced red-cell transfusion if their hemoglobin dropped either <70 g/L (restrictive) or 95 g/L (liberal). Measurements and Main Results: Postoperative cardiac patients (n = 125) from seven centers were enrolled. The restrictive (n = 63) and liberal (n = 62) groups were similar at baseline in age (mean ± standard deviation = 31.4 ± 38.1 mos vs. 26.4 ± 39.1 mos), surgical procedure, severity of illness (Pediatric Risk of Mortality score = 3.4 ± 3.2 vs. 3.2 ± 3.2), multiple organ dysfunction syndrome (46% vs. 44%), mechanical ventilation (62% vs. 60%), and hemoglobin (83 vs. 80 g/L). Mean hemoglobin remained 21 g/L lower in the restrictive group after randomization. No significant difference was found in new or progressive multiple organ dysfunction syndrome (primary outcome) in the restrictive group vs. liberal group (12.7% vs. 6.5%; p = .36), pediatric intensive care unit length of stay (7.0 ± 5.0 days vs. 7.4 ± 6.4 days) or 28-day mortality (3.2% vs. 3.2%). Conclusion: In this subgroup analysis of cardiac surgery patients, a restrictive red-cell transfusion strategy, as compared with a liberal one, was not associated with any significant difference in new or progressive multiple organ dysfunction syndrome, but this evidence is not definitive.

Multicentre validation of the bedside paediatric early warning system score: a severity of illness score to detect evolving critical illness in hospitalised children

IntroductionThe timely provision of critical care to hospitalised patients at risk for cardiopulmonary arrest is contingent upon identification and referral by frontline providers. Current approaches require improvement. In a single-centre study, we developed the Bedside Paediatric Early Warning System (Bedside PEWS) score to identify patients at risk. The objective of this study was to validate the Bedside PEWS score in a large patient population at multiple hospitals.MethodsWe performed an international, multicentre, case-control study of children admitted to hospital inpatient units with no limitations on care. Case patients had experienced a clinical deterioration event involving either an immediate call to a resuscitation team or urgent admission to a paediatric intensive care unit. Control patients had no events. The scores ranged from 0 to 26 and were assessed in the 24 hours prior to the clinical deterioration event. Score performance was assessed using the area under the receiver operating characteristic (AUCROC) curve by comparison with the retrospective rating of nurses and the temporal progression of scores in case patients.ResultsA total of 2,074 patients were evaluated at 4 participating hospitals. The median (interquartile range) maximum Bedside PEWS scores for the 12 hours ending 1 hour before the clinical deterioration event were 8 (5 to 12) in case patients and 2 (1 to 4) in control patients (P < 0.0001). The AUCROC curve (95% confidence interval) was 0.87 (0.85 to 0.89). In case patients, mean scores were 5.3 at 20 to 24 hours and 8.4 at 0 to 4 hours before the event (P < 0.0001). The AUCROC curve (95% CI) of the retrospective nurse ratings was 0.83 (0.81 to 0.86). This was significantly lower than that of the Bedside PEWS score (P < 0.0001).ConclusionsThe Bedside PEWS score identified children at risk for cardiopulmonary arrest. Scores were elevated and continued to increase in the 24 hours before the clinical deterioration event. Prospective clinical evaluation is needed to determine whether this score will improve the quality of care and patient outcomes.

Long-term ventilation in children: longitudinal trends and outcomes

Background Cross-sectional studies have suggested a rapid expansion in paediatric long-term ventilation (LTV) over the last 20 years but information on longitudinal trends is limited. Methods Data were collected prospectively on all patients receiving LTV over a 15-year period (1.1.95–31.12.09) in a single regional referral centre. Results 144 children commenced LTV during the 15-year period. The incidence of LTV increased significantly over time, with an accompanying 10-fold increase in prevalence due to a significant increase in institution of non-invasive ventilation (NIV). There was no significant increase in invasive ventilation. 5-year survival was 94% overall and was significantly higher for patients on NIV (97%) than invasively ventilated patients (84%). 10-year survival was 91% overall. Although some children were able to discontinue respiratory support (21% at 5 years and 42% at 10 years), the number of patients transitioned to adult services increased significantly over time (26% of total cohort). Patients with neuromuscular disease were less likely to discontinue support than other patients. Conclusions The paediatric LTV population has expanded significantly over 15 years. Future planning of paediatric hospital and community services, as well as adult services, must take into account the needs of this growing population.

Development of a Screening Tool for Sleep Disordered Breathing in Children Using the Phone Oximeter

Background Sleep disordered breathing (SDB) can lead to daytime sleepiness, growth failure and developmental delay in children. Polysomnography (PSG), the gold standard to diagnose SDB, is a highly resource-intensive test, confined to the sleep laboratory. Aim To combine the blood oxygen saturation (SpO2) characterization and cardiac modulation, quantified by pulse rate variability (PRV), to identify children with SDB using the Phone Oximeter, a device integrating a pulse oximeter with a smartphone. Methods Following ethics approval and informed consent, 160 children referred to British Columbia Childrens Hospital for overnight PSG were recruited. A second pulse oximeter sensor applied to the finger adjacent to the one used for standard PSG was attached to the Phone Oximeter to record overnight pulse oximetry (SpO2 and photoplethysmogram (PPG)) alongside the PSG. Results We studied 146 children through the analysis of the SpO2 pattern, and PRV as an estimate of heart rate variability calculated from the PPG. SpO2 variability and SpO2 spectral power at low frequency, was significantly higher in children with SDB due to the modulation provoked by airway obstruction during sleep (p-value ). PRV analysis reflected a significant augmentation of sympathetic activity provoked by intermittent hypoxia in SDB children. A linear classifier was trained with the most discriminating features to identify children with SDB. The classifier was validated with internal and external cross-validation, providing a high negative predictive value (92.6%) and a good balance between sensitivity (88.4%) and specificity (83.6%). Combining SpO2 and PRV analysis improved the classification performance, providing an area under the receiver operating characteristic curve of 88%, beyond the 82% achieved using SpO2 analysis alone. Conclusions These results demonstrate that the implementation of this algorithm in the Phone Oximeter will provide an improved portable, at-home screening tool, with the capability of monitoring patients over multiple nights.

Cost-benefit of trained transport teams: estimates for head-injured children.

Introduction. Care during transport influences the outcome of head-injured children. Secondary adverse events, e.g., hypotension and hypoxia, worsen morbidity and mortality. Trained transport teams lower the incidence of such secondary “insults.” Objective. To estimate the cost-benefit of improved care from trained escorts. Methods. The setting was a provincial air ambulance service during transition to trained pediatric escort paramedics. A retrospective review of transport and hospital records for a 12-month period was conducted. All children with head injuries (n = 43) transported to tertiary care [11 by untrained escorts (UE), 32 by trained escorts (TE)] were enrolled. Severity of injury was classified by Glasgow Coma Score (GCS); incidence of adverse events was counted and cost of change of severity resulting from preventable insults was estimated using published care costs. Results. There were 13 preventable insults in six patients (55%) in the UE group and five preventable insults in four patients (12%) in the TE group (p < 0.05). Among those in the UE group, two changed in severity from moderate to severe, one moderate worsened (decrease in GCS of 2 or more), and two severe worsened. In the TE group, there were no changes > 1. Cost-benefit estimates based on change in severity were

Oxygen saturation in children with and without obstructive sleep apnea using the phone-oximeter

136,000 (median) to

Pulse rate variability compared with heart rate variability in children with and without sleep disordered breathing

238,000 (mean). Conclusion. Significant cost-benefit likely accrues from training escorts who transport children with significant head injuries to tertiary care.

Evaluating processes of care and outcomes of children in hospital (EPOCH): study protocol for a randomized controlled trial

Obstructive sleep apnea (OSA) in children can lead to daytime sleepiness, growth failure and developmental delay. Polysomnography (PSG), the gold standard to diagnose OSA is highly resource intensive and is confined to the sleep laboratory. In this study we propose to identify children with OSA using blood oxygen saturation (SpO2) obtained from the Phone Oximeter. This portable, in-home device is able to monitor patients over multiple nights, causes less sleep disturbance and facilitates a more natural sleep pattern. The proposed algorithm analyzes the SpO2 signal in the time and frequency domain using a 90-s sliding window. Three spectral parameters are calculated from the power spectral density (PSD) to evaluate the modulation in the SpO2 due to the oxyhemoblobin desaturations. The power P, slope S in the discriminant band (DB), and ratio R between P and total power are calculated for each window. Tendency and variability indices, number of SpO2 desaturations and time spent under 2% or 3% of baseline saturation level are computed for each time window. The statistical distribution of the temporal evolution of all parameters is analyzed to identify 68 children, 30 with OSA and 38 without OSA (nonOSA). This characterization was evaluated by a feature selection based on a linear discriminant. The combination of temporal and spectral parameters provided the best leave one out crossvalidation results with an accuracy of 86.8%, a sensitivity of 80.0%, and a specificity of 92.1% using only 5 parameters. The median of R, mean of P and S and mean and standard deviation of the number of desaturations below 3% of baseline saturation level, were the most representative parameters. Hence, a better knowledge of SpO2 dynamics could help identifying children with OSA with the Phone Oximeter.

A Randomized Controlled Trial of Corticosteroids in Pediatric Septic Shock: A Pilot Feasibility Study*

Heart Rate Variability (HRV), the variation of time intervals between heartbeats, is one of the most promising and widely used quantitative markers of autonomic activity. Traditionally, HRV is measured as the series of instantaneous cycle intervals obtained from the electrocardiogram (ECG). In this study, we investigated the estimation of variation in heart rate from a photoplethysmography (PPG) signal, called pulse rate variability (PRV), and assessed its accuracy as an estimate of HRV in children with and without sleep disordered breathing (SDB). We recorded raw PPGs from 72 children using the Phone Oximeter, an oximeter connected to a mobile phone. Full polysomnography including ECG was simultaneously recorded for each subject. We used correlation and Bland-Altman analysis for comparing the parameters of HRV and PRV between two groups of children. Significant correlation (r > 0.90, p <; 0.05) and close agreement were found between HRV and PRV for mean intervals, standard deviation of intervals (SDNN) and the root-mean square of the difference of successive intervals (RMSSD). However Bland-Altman analysis showed a large divergence for LF/HF ratio parameter. In addition, children with SDB had depressed SDNN and RMSSD and elevated LF/HF in comparison to children without SDB. In conclusion, PRV provides the accurate estimate of HRV in time domain analysis but does not reflect precise estimation for parameters in frequency domain.

Evaluation of Cardiac Modulation in Children in Response to Apnea / Hypopnea using the Phone Oximeter

BackgroundThe prevention of near and actual cardiopulmonary arrest in hospitalized children is a patient safety imperative. Prevention is contingent upon the timely identification, referral and treatment of children who are deteriorating clinically. We designed and validated a documentation-based system of care to permit identification and referral as well as facilitate provision of timely treatment. We called it the Bedside Paediatric Early Warning System (BedsidePEWS). Here we describe the rationale for the design, intervention and outcomes of the study entitled Evaluating Processes and Outcomes of Children in Hospital (EPOCH).Methods/DesignEPOCH is a cluster-randomized trial of the BedsidePEWS. The unit of randomization is the participating hospital. Eligible hospitals have a Pediatric Intensive Care Unit (PICU), are anticipated to have organizational stability throughout the study, are not using a severity of illness score in hospital wards and are willing to be randomized. Patients are >37 weeks gestational age and <18 years and are hospitalized in inpatient ward areas during all or part of their hospital admission.Randomization is to either BedsidePEWS or control (no severity of illness score) in a 1:1 ratio within two strata (<200, ≥200 hospital beds). All-cause hospital mortality is the selected primary outcome. It is objective, independent of do-not-resuscitate status and can be reliably measured. The secondary outcomes include (1) clinical outcomes: clinical deterioration, severity of illness at and during ICU admission, and potentially preventable cardiac arrest; (2) processes of care outcomes: immediate calls for assistance, hospital and ICU readmission, and perceptions of healthcare professionals; and (3) resource utilization: ICU days and use of ICU therapies.DiscussionFollowing funding by the Canadian Institutes of Health Research and local ethical approvals, site enrollment started in 2010 and was closed in February 2014. Patient enrollment is anticipated to be complete in July 2015. The results of EPOCH will strengthen the scientific basis for local, regional, provincial and national decision-making and for the recommendations of national and international bodies. If negative, the costs of hospital-wide implementation can be avoided. If positive, EPOCH will have provided a scientific justification for the major system-level changes required for implementation.Trial registration: NCT01260831 ClinicalTrials.gov date: 14 December 2010.