Accuracy of a portable pulse oximeter in monitoring hypoxemic infants with cyanotic heart disease

OBJECTIVE

Infants with single ventricle physiology have arterial oxygen saturations between 75 and 85%. Home monitoring with daily pulse oximetry is associated with improved interstage survival. They are typically sent home with expensive, bulky, hospital-grade pulse oximeters. This study evaluates the accuracy of both the currently used Masimo LNCS and a relatively inexpensive, portable, and equipped with Bluetooth technology study device, by comparing with the gold standard co-oximeter.

DESIGN

Prospective, observational study.

SETTING

Single institution, paediatric cardiac critical care unit, and neonatal ICU.

INTERVENTIONS

none.

PATIENTS

Twenty-four infants under 12 months of age with baseline oxygen saturation less than 90% due to cyanotic CHD.

MEASUREMENTS AND RESULTS

Pulse oximetry with WristOx2 3150 with infant sensors 8008 J (study device) and Masimo LCNS saturation sensor connected to a Philips monitor (hospital device) were measured simultaneously and compared to arterial oxy-haemoglobin saturation measured by co-oximetry. Statistical analysis evaluated the performances of each and compared to co-oximetry with Schuirmann's TOST equivalence tests, with equivalence defined as an absolute difference of 5% saturation or less. Neither the study nor the hospital device met the predefined standard for equivalence when compared with co-oximetry. The study device reading was on average 4.0% higher than the co-oximeter, failing to show statistical equivalence (p = 0.16). The hospital device was 7.4% higher than the co-oximeter and also did not meet the predefined standard for equivalence (p = 0.97).

CONCLUSION

Both devices tended to overestimate oxygen saturation in this patient population when compared to the gold standard, co-oximetry. The study device is at least as accurate as the hospital device and offers the advantage of being more portable with Bluetooth technology that allows reliable, efficient data transmission. Currently FDA-approved, smaller portable pulse oximeters can be considered for use in home monitoring programmes.

Neurodevelopmental outcomes at 2 and 4 years in children with congenital heart disease

BACKGROUND AND OBJECTIVES

Children with congenital heart disease (CHD) are at risk for neurodevelopmental (ND) delays. The purpose of this study is to compare the ND testing results of children with CHD at 2 and 4 years of age and determine if rates of ND delays change over time.

METHODS

Children with CHD completed the Bayley Scales of Infant Development-III (BSID-III) at 2 years of age, and standardized neuropsychological measures at 4 years. Scores were compared with test norms and were classified as: average (within one SD of test mean); at risk (1-2 SDs from the test mean); and delayed (>2 SD from test mean). Pearson correlations and McNemar's exact tests were performed to determine the relationship between test scores at the two times of assessment.

RESULTS

Sixty-four patients completed evaluations at 24 ± 3 months of age and 4 years of age. BSID-III cognitive and fine motor scores were correlated with preschool IQ and fine motor scores, r = .75 to .87, P < .0001. Agreement in score categories was 79% for cognitive and 61% for fine motor. More patients had at risk or delayed scores at age 4 vs age 2 (P ≤ .01).

CONCLUSION(S)

Despite significant correlations between 2- and 4-year-old test scores, many patients who scored in the average range at age 2 showed deficits at age 4. BSID-III scores at age 2 may underestimate delays. Therefore, longitudinal ND assessment is recommended.

Preschool Neurodevelopmental Outcomes in Children with Congenital Heart Disease

OBJECTIVE

To describe preschool neurodevelopmental outcomes of children with complex congenital heart disease (CHD), who were evaluated as part of a longitudinal cardiac neurodevelopmental follow-up program, as recommended by the American Heart Association and the American Academy of Pediatrics, and identify predictors of neurodevelopmental outcomes in these children.

STUDY DESIGN

Children with CHD meeting the American Heart Association/American Academy of Pediatrics high-risk criteria for neurodevelopmental delay were evaluated at 4-5 years of age. Testing included standardized neuropsychological measures. Parents completed measures of child functioning. Scores were compared by group (single ventricle [1V]; 2 ventricles [2V]; CHD plus known genetic condition) to test norms and classified as: normal (within 1 SD of mean); at risk (1-2 SD from mean); and impaired (>2 SD from mean).

RESULTS

Data on 102 patients were analyzed. Neurodevelopmental scores did not differ based on cardiac anatomy (1V vs 2V); both groups scored lower than norms on fine motor and adaptive behavior skills, but were within 1 SD of norms. Patients with genetic conditions scored significantly worse than 1V and 2V groups and test norms on most measures.

CONCLUSIONS

Children with CHD and genetic conditions are at greatest neurodevelopmental risk. Deficits in children with CHD without genetic conditions were mild and may not be detected without formal longitudinal testing. Parents and providers need additional education regarding the importance of developmental follow-up for children with CHD.

Bone density in children with single ventricle physiology

Children with chronic diseases are at risk for low bone mineral density (BMD). There are no studies of BMD in children with congenital heart disease and particularly single ventricle (SV). Children with this defect are often treated with warfarin, suspected to negatively impact BMD in adults. We assessed BMD in patients with SV physiology and compared the BMD of subjects taking warfarin to those who were not. Subjects 5-12 years with SV were included. BMD z scores by dual-energy X-ray absorptiometry of the spine and total body less head (TBLH) were obtained. Calcium intake, activity level, height, and Tanner stage were assessed. Linear regression models and t tests were used to investigate differences between participants and normative data as well as between subjects' subgroups. Twenty-six subjects were included and 16 took warfarin. Mean BMD z score at the spine was significantly lower than expected at -1.0 ± 0.2 (p < 0.0001), as was the BMD z score for TBLH at -0.8 ± 0.2 (p < 0.0001). Those results remained significant after adjusting for height. Subjects who were on warfarin tended to have lower BMD at both the spine and TBLH than those who were not, with a z score difference of 0.6 ± 0.46 at the spine (p = 0.106) and a difference of 0.4 ± 0.34 at TBLH (p = 0.132). BMD is significantly reduced in children with SV. Warfarin appears to lower BMD but the effect is less conclusive. Continued evaluation is recommended for these patients at risk for reduced bone density. Evaluation of other cardiac patients on warfarin therapy should also be considered.

Impact of educational video on critical congenital heart disease screening

OBJECTIVE

To assess the status of pulse oximetry screening and barriers to implementing screening programs.

METHODS

This was a prospective pre-post intervention survey of nurse managers and medical directors of hospital-based birthing centers in Oregon, Idaho, and Southern Washington. The intervention was a 7-minute video demonstrating and discussing pulse oximetry screening for critical congenital heart disease.

RESULTS

Analysis of matched pairs showed a significant increase in the use of pulse oximetry screening during the study period from 52% to 73% (P < .0001). Following implementation of the video, the perception of all queried potential barriers decreased significantly among individuals from hospitals self-identified as nonscreening at baseline. Viewing the educational video was associated with an increase in the percentage of individuals from nonscreening hospitals that rated screening as "very beneficial" (45% vs 90%, P = .0001).

CONCLUSIONS

An educational video was associated with improved opinions of pulse oximetry screening among hospitals not currently screening.

Accuracy of pulse oximetry in children

OBJECTIVE

For children with cyanotic congenital heart disease or acute hypoxemic respiratory failure, providers frequently make decisions based on pulse oximetry, in the absence of an arterial blood gas. The study objective was to measure the accuracy of pulse oximetry in the saturations from pulse oximetry (SpO2) range of 65% to 97%.

METHODS

This institutional review board-approved prospective, multicenter observational study in 5 PICUs included 225 mechanically ventilated children with an arterial catheter. With each arterial blood gas sample, SpO2 from pulse oximetry and arterial oxygen saturations from CO-oximetry (SaO2) were simultaneously obtained if the SpO2 was ≤ 97%.

RESULTS

The lowest SpO2 obtained in the study was 65%. In the range of SpO2 65% to 97%, 1980 simultaneous values for SpO2 and SaO2 were obtained. The bias (SpO2 - SaO2) varied through the range of SpO2 values. The bias was greatest in the SpO2 range 81% to 85% (336 samples, median 6%, mean 6.6%, accuracy root mean squared 9.1%). SpO2 measurements were close to SaO2 in the SpO2 range 91% to 97% (901 samples, median 1%, mean 1.5%, accuracy root mean squared 4.2%).

CONCLUSIONS

Previous studies on pulse oximeter accuracy in children present a single number for bias. This study identified that the accuracy of pulse oximetry varies significantly as a function of the SpO2 range. Saturations measured by pulse oximetry on average overestimate SaO2 from CO-oximetry in the SpO2 range of 76% to 90%. Better pulse oximetry algorithms are needed for accurate assessment of children with saturations in the hypoxemic range.

Neurodevelopmental outcomes for children with hypoplastic left heart syndrome at the age of 5 years

This study aimed to determine the neurodevelopmental (ND) outcome for children with hypoplastic left heart syndrome (HLHS) at early school age. English-speaking patients who underwent the Norwood procedure between 2000 and 2005 were eligible at 4-6 years of age for ND testing. Of the 72 eligible patients, 44 (61 %) agreed to participate, and 37 completed ND testing before the close of the study. Three subjects were excluded from analyses due to late stroke. The ND testing included intelligence, visual motor integration, memory and motor and language skills. Parents and teachers completed measures of behavior and attention problems. Subjects' scores and parent/teacher ratings were converted to z-scores and compared with test norms. Higher scores on child measures represent better outcomes, whereas higher scores on parent and teacher rating scales indicate more problems. The average ND performance of the tested cohort fell within one standard deviation of the test norms for all measures. However, the subjects performed significantly lower than the test norms on measures of visual-motor integration, fine motor skills, memory, and word structure (z = -0.42 to -0.54; p < 0.005). On the parent and teacher completed measures, the subjects scored higher than the test norms on attention problems (z = 0.40-0.62; p < 0.005). Although the overall ND performance of the cohort was normal, the subjects showed relative weakness in visual motor and attention skills. Ongoing developmental monitoring of these children is recommended to guide interventions that may improve individual outcomes and to assess the impact of changes in clinical management strategies on functional outcomes.

Results from the New Jersey statewide critical congenital heart defects screening program

BACKGROUND AND OBJECTIVE

New Jersey was the first state to implement legislatively mandated newborn pulse oximetry screening (POxS) in all licensed birthing facilities to detect critical congenital heart defects (CCHDs). The objective of this report was to evaluate implementation of New Jersey's statewide POxS mandate.

METHODS

A 2-pronged approach was used to collect data on infants screened in all New Jersey birthing facilities from August 31, 2011, through May 31, 2012. Aggregate screening results were submitted by each birthing facility. Data on failed screens and clinical characteristics of those newborns were reported to the New Jersey Birth Defects Registry (NJBDR). Three indicators were used to distinguish the added value of mandated POxS from standard clinical care: prenatal congenital heart defect diagnosis, cardiology consultation or echocardiogram indicated or performed before PoxS, or clinical findings at the time of POxS warranting a pulse oximetry measurement.

RESULTS

Of 75,324 live births in licensed New Jersey birthing facilities, 73,320 were eligible for screening, of which 99% were screened. Forty-nine infants with failed POxS were reported to the NJBDR, 30 of whom had diagnostic evaluations solely attributable to the mandated screening. Three of the 30 infants had previously unsuspected CCHDs and 17 had other diagnoses or non-CCHD echocardiogram findings.

CONCLUSIONS

In the first 9 months after implementation, New Jersey achieved a high statewide screening rate and established surveillance mechanisms to evaluate the unique contribution of POxS. The screening mandate identified 3 infants with previously unsuspected CCHDs that otherwise might have resulted in significant morbidity and mortality and also identified other significant secondary targets such as sepsis and pneumonia.

Temporal trends in survival among infants with critical congenital heart defects

OBJECTIVE

To evaluate the trends in survival for infants with critical congenital heart defects (CCHDs) and to examine the potential impact of timing of diagnosis and other prognostic factors on survival.

METHODS

We performed a retrospective population-based cohort study in infants born with structural congenital heart defects (CHDs) between 1979 and 2005 and ascertained by the Metropolitan Atlanta Congenital Defects Program. We estimated Kaplan-Meier survival probabilities for 12 CCHD phenotypes by birth era and timing of diagnosis among infants without noncardiac defects or chromosomal disorders and used stratified Cox proportional hazards models to assess potential prognostic factors.

RESULTS

Of 1 056 541 births, there were 6965 infants with CHDs (1830 with CCHDs). One-year survival was 75.2% for those with CCHDs (n = 1336) vs 97.1% for those with noncritical CHDs (n = 3530; P < .001). One-year survival for infants with CCHDs improved from 67.4% for the 1979-1993 birth era to 82.5% for the 1994-2005 era (P < .001). One-year survival was 71.7% for infants with CCHDs diagnosed at ≤1 day of age (n = 890) vs 82.5% for those with CCHDs diagnosed at >1 day of age (n = 405; P < .001). There was a significantly higher risk of 1-year mortality for infants with an earlier birth era, earlier diagnosis, and low birth weight and whose mothers were <30 years old.

CONCLUSIONS

One-year survival for infants with CCHDs has been improving over time, yet mortality remains high. Later diagnosis is associated with improved 1-year survival. These benchmark data and identified prognostic factors may aid future evaluations of the impact of pulse oximetry screening on survival from CCHDs.

Inpatient costs and charges for surgical treatment of hypoplastic left heart syndrome

OBJECTIVE

Hypoplastic left heart syndrome (HLHS) is one of the most serious congenital cardiac anomalies. Typically, it is managed with a series of 3 palliative operations or cardiac transplantation. Our goal was to quantify the inpatient resource burden of HLHS across multiple academic medical centers.

METHODS

The University HealthSystem Consortium is an alliance of 101 academic medical centers and 178 affiliated hospitals that share diagnostic, procedural, and financial data on all discharges. We examined inpatient resource use by patients with HLHS who underwent a staged palliative procedure or cardiac transplantation between 1998 and 2007.

RESULTS

Among 1941 neonates, stage 1 palliation (Norwood or Sano procedure) had a median length of stay (LOS) of 25 days and charges of $214,680. Stage 2 and stage 3 palliation (Glenn and Fontan procedures, respectively) had median LOS and charges of 8 days and $82,174 and 11 days and $79,549, respectively. Primary neonatal transplantation had an LOS of 87 days and charges of $582,920, and rescue transplantation required 36 days and $411,121. The median inpatient wait time for primary and rescue transplants was 42 and 6 days, respectively. Between 1998 and 2007, the LOS for stage 1 palliation increased from 16 to 28 days and inflation-adjusted charges increased from $122,309 to $280,909, largely because of increasing survival rates (57% in 1998 and 83% in 2007).

CONCLUSIONS

Patients with HLHS demand considerable inpatient resources, whether treated with the Norwood-Glenn-Fontan procedure pathway or cardiac transplantation. Improved survival rates have led to increased hospital stays and costs.