Sotirios Fouzas

Pulse Oximetry in Pediatric Practice

The introduction of pulse oximetry in clinical practice has allowed for simple, noninvasive, and reasonably accurate estimation of arterial oxygen saturation. Pulse oximetry is routinely used in the emergency department, the pediatric ward, and in pediatric intensive and perioperative care. However, clinically relevant principles and inherent limitations of the method are not always well understood by health care professionals caring for children. The calculation of the percentage of arterial oxyhemoglobin is based on the distinct characteristics of light absorption in the red and infrared spectra by oxygenated versus deoxygenated hemoglobin and takes advantage of the variation in light absorption caused by the pulsatility of arterial blood. Computation of oxygen saturation is achieved with the use of calibration algorithms. Safe use of pulse oximetry requires knowledge of its limitations, which include motion artifacts, poor perfusion at the site of measurement, irregular rhythms, ambient light or electromagnetic interference, skin pigmentation, nail polish, calibration assumptions, probe positioning, time lag in detecting hypoxic events, venous pulsation, intravenous dyes, and presence of abnormal hemoglobin molecules. In this review we describe the physiologic principles and limitations of pulse oximetry, discuss normal values, and highlight its importance in common pediatric diseases, in which the principle mechanism of hypoxemia is ventilation/perfusion mismatch (eg, asthma exacerbation, acute bronchiolitis, pneumonia) versus hypoventilation (eg, laryngotracheitis, vocal cord dysfunction, foreign-body aspiration in the larynx or trachea). Additional technologic advancements in pulse oximetry and its incorporation into evidence-based clinical algorithms will improve the efficiency of the method in daily pediatric practice.

DMSA Scan for Revealing Vesicoureteral Reflux in Young Children With Urinary Tract Infection

OBJECTIVES: The objective of this study was to assess the ability of acute dimercaptosuccinic acid (DMSA) scintigraphy for revealing vesicoureteral reflux (VUR) in young children after a first febrile urinary tract infection (UTI). METHODS: Children aged ≤24 months and were admitted with a first febrile UTI during a 5-year period were evaluated. The ability of acute DMSA scintigraphy to reveal dilating (grades 3–5) or severe (grades 4–5) VUR was assessed by comparing DMSA scan findings with those of voiding cystourethrography. RESULTS: Of the 296 children included, 46 had dilating and 25 severe VUR. Abnormal DMSA scan results were associated with an odds ratio of 4.36 for dilating and 5.50 for severe VUR. For detecting dilating VUR, the area under the curve (AUC) was 0.68, the positive likelihood ratio (LR) was 2.00, and the negative LR was 0.46; for severe VUR, those values were 0.69, 2.10, and 0.38, respectively. Children with abnormal DMSA scan results combined with abnormal ultrasonography had an odds ratio of 3.60 for dilating and 6.32 for severe VUR. Despite normal findings on both investigations, 12 children had dilating and 4 severe VUR. For dilating VUR, the area under the (AUC) was 0.65, the positive LR was 1.70, and the negative LR was 0.47; for severe VUR, the values were 0.69, 1.90, and 0.29, respectively. CONCLUSIONS: Our data suggest that acute DMSA scintigraphy has limited overall ability in identifying VUR and should not be endorsed as replacement for voiding cystourethrography in the evaluation of young children with a first febrile UTI.

Transcutaneous Bilirubin Nomogram for Prediction of Significant Neonatal Hyperbilirubinemia

OBJECTIVE: The goal was to develop a predictive nomogram, based on transcutaneous bilirubin (TcB) measurements, for assessment of the risk of significant hyperbilirubinemia in healthy term and near-term neonates. METHODS: A total of 10382 TcB measurements were performed with 2039 healthy neonates (gestational age of ≥35 weeks and birth weight of ≥2000 g), with a BiliCheck bilirubinometer (SpectRx, Norcross, GA), at designated time points between 12 and 120 hours of life. According to their severity, these TcB measurements were selectively cross-checked with a direct spectrophotometric device, and significant hyperbilirubinemia was defined on the basis of the hour-specific threshold values for phototherapy proposed by the American Academy of Pediatrics. With the use of likelihood ratios (LRs), the high- and low-risk demarcators for each designated time were calculated and presented on an hour-specific nomogram. RESULTS: Significant hyperbilirubinemia was documented for 122 neonates (6%). At 24 hours of life, the high-risk zone of the nomogram had 73.9% sensitivity and a positive LR of 12.1 in predicting significant hyperbilirubinemia, whereas the low-risk zone had 97.7% sensitivity and a negative LR of 0.04. At 48 hours, the high-risk zone had 90% sensitivity and a positive LR of 12.1, whereas the low-risk zone had 98.8% sensitivity and a negative LR of 0.02. In our study population, the probability of significant hyperbilirubinemia would be >35% for values in the high-risk zone and <0.5% for values in the low-risk zone of the nomogram. CONCLUSIONS: We provide a predictive TcB tool that could allow for a noninvasive, risk-based approach to neonatal hyperbilirubinemia.

Transcutaneous Bilirubin Levels for the First 120 Postnatal Hours in Healthy Neonates

OBJECTIVE: The objective of this study was to provide data on transcutaneous bilirubin (TcB) levels for the first 120 postnatal hours and to develop an hour-specific TcB nomogram for healthy term and near-term neonates. METHODS: From September 2005 to August 2008, we obtained 14864 TcB measurements from 2818 healthy neonates (gestational age ≥ 35 weeks and birth weight ≥ 2000 g). All measurements were performed with the BiliCheck bilirubinometer, at designated times from 12 to 120 postnatal hours. TcB percentiles for each designated time were calculated and used for the development of an hour-specific nomogram. TcB percentiles for neonates who required phototherapy are also presented. RESULTS: The developed TcB nomogram reflects the natural history of TcB levels in healthy neonates up to the fifth postnatal day. A different pattern of TcB increasing rate was noted in neonates who did and did not require phototherapy but with substantial overlap of TcB values between the 2 groups. CONCLUSIONS: We provide data on TcB levels for the first 120 postnatal hours from a large population of white, healthy, term and near-term neonates. We also present a percentile-based TcB nomogram designated for noninvasive and hour-specific evaluation of neonatal hyperbilirubinemia.

Neonatal cardiac dysfunction in intrauterine growth restriction

Background:The early postnatal cardiovascular consequences of intrauterine growth restriction (IUGR) have not been completely elucidated. This study aimed to evaluate the effect of IUGR on neonatal myocardial function and cardiovascular adaptation to extrauterine life.Methods:Conventional and tissue Doppler echocardiographic parameters were compared on the second and fifth postnatal day between 30 IUGR and 30 appropriate-for-gestational age (AGA) neonates.Results:IUGR neonates presented relative interventricular septum (IVS) hypertrophy (IVS to left ventricular (LV) posterior wall diastolic ratio: median IUGR–AGA difference of 0.05 (interquartile range: 0.04–0.06); P = 0.020), relative LV dilatation (wall thickness to end-diastolic LV dimension difference of 0.12 (0.06–0.16); P = 0.012), and increased left myocardial performance index (MPI difference of 0.19 (0.05–0.28); P = 0.012). Repeated measurements ANOVA revealed a different pattern of change in LV stroke volume (LVSV; P < 0.001), LV cardiac output (LVCO; P < 0.001), MPI (P < 0.001), and heart rate (HR; P = 0.025) between AGA and IUGR infants. From the second to the fifth postnatal day, AGA neonates presented a decrease in MPI and HR with an increase in LVSV and LVCO. IUGR neonates failed to achieve similar changes in MPI, HR, and LVSV, whereas their LVCO decreased.Conclusion:IUGR neonates present changes in cardiac morphology and subclinical myocardial dysfunction, which may result in an altered pattern of cardiovascular adaptation to extrauterine life.

Predicting persistence of asthma in preschool wheezers : crystal balls or muddy waters?

Since preschool wheezing is the common expression of several heterogeneous disorders, identification of children at risk for persistent asthma is particularly challenging. To date, efforts to predict the outcome of preschool wheeze have mainly relied on predictive rules consisting of simple clinical and laboratory parameters. Among these tools, the asthma predictive index (API) has been introduced in international guidelines and position papers and is recommended for use in clinical practice. This article reviews the currently available asthma predictive models focusing on their validity and performance characteristics. Although these tools are generally simple and easy to apply, they suffer important intrinsic and practical limitations and they have been insufficiently validated to allow for widespread use in clinical settings. We also present evidence that their ability to predict the long-term outcome of preschool wheeze is limited in general populations, and even poorer in high-risk children in which prediction of asthma persistence might have important clinical and prognostic implications. Due to the complex and multifactorial nature of asthma, prediction of asthma persistence based on simple clinical models is practically impossible.

Sex-specific trends in prevalence of childhood asthma over 30 years in Patras, Greece

Aim:  According to four surveys conducted during 1978–2003, the prevalence of childhood asthma and wheezing has risen in the city of Patras, Greece, albeit at a decelerating rate. We examined sex‐specific wheeze and asthma prevalence in the same urban environment in 2008.

Volumetric Capnography in Infants with Bronchopulmonary Dysplasia

OBJECTIVES To assess the feasibility of using volumetric capnography in spontaneously breathing small infants and its ability to discriminate between infants with and without bronchopulmonary dysplasia (BPD). STUDY DESIGN Lung function variables for 231 infants (102 term, 52 healthy preterm, 77 BPD), matched for post-conceptional age of 44 weeks, were collected. BPD was defined as supplemental oxygen requirement at 36 weeks post-menstrual age. Tidal breath-by-breath volume capnograms were obtained by mainstream capnography. The capnographic slope of phase II (SII) and slope of phase III (SIII) were calculated and compared between study groups. The effect of BPD, tidal volume (VT), respiratory rate (RR), and prematurity on the magnitude of the slopes was assessed. RESULTS SII was steeper in infants with BPD (100 ± 28/L) compared with healthy preterm (88 ± 22/L; P = .007) and term infants (79 ± 18/L; P < .001), but this finding was attributed to differences in VT, RR, and gestational age. SIII was steeper in the BPD group (26.8 ± 14.1/L) compared with healthy preterm (16.2 ± 6.2/L; P < .001) and term controls (14.8 ± 5.4/L; P < .001). BPD was a significant predictor of SIII independently of VT, RR, and gestational age. The ability of SIII to discriminate between BPD and controls was significantly higher compared with lung clearance index (area under the curve 0.83 vs 0.56; P < .001). CONCLUSIONS Volumetric capnography may provide valuable information regarding functional lung alterations related to BPD and might be considered as an alternative to more involved lung function techniques for monitoring chronic lung disease during early infancy.

Cesarean section delivery and development of food allergy and atopic dermatitis in early childhood

Delivery by Cesarean section (CS) may predispose to allergic disorders, presumably due to alterations in the establishment of normal gut microbiota in early infancy. In this study, we sought to investigate the association between CS and physician‐diagnosed food allergy and atopic dermatitis during the first 3 years of life, using data from a homogeneous, population‐based, birth cohort.

Functional evidence for continued alveolarisation in former preterms at school age

Prematurity is the most common disruptor of lung development. The aim of our study was to examine the function of the more vulnerable peripheral airways in former preterm children by multiple-breath washout (MBW) measurements. 86 school-aged children, born between 24 and 35 weeks of gestation and 49 term-born children performed nitrogen MBW. Lung clearance index (LCI), and slope III-derived Scond and Sacin were assessed as markers for global, convection-dependent and diffusion–convection-dependent ventilation inhomogeneity, respectively. We analysed the data of 77 former preterm (mean (range) age 9.5 (7.2–12.8) years) and 46 term-born children (mean age 9.9 (6.0–15.9) years). LCI and Sacin did not differ between preterm and term-born children. Scond was significantly elevated in preterm compared to term-born participants (mean difference z-score 1.74, 95% CI 1.17–2.30; p<0.001), with 54% of former preterm children showing elevated Scond. In multivariable regression analysis Scond was significantly related only to gestational age (R2=0.37). Normal Sacin provides evidence for a functionally normal alveolar compartment, while elevated Scond indicates impaired function of more proximal conducting airways. Together, our findings support the concept of continued alveolarisation, albeit with “dysanaptic” lung growth in former preterm children. Evidence for a prematurity-related dysanaptic lung growth in former preterm children http://ow.ly/RUXUl