In a special care baby unit, neonates, mainly premature, encounter serious to life-threatening di... more In a special care baby unit, neonates, mainly premature, encounter serious to life-threatening diseases, the timely diagnosis and treatment of which may require a large number of radiographs. Increased neonatal radiosensitivity and longer life expectancy increase the risk of radiation-induced cancer, which emphasizes the importance of minimizing dose while maintaining clinically satisfactory image quality. An optimization study on radiation dose and image quality in neonatal radiography is presented. Neonates were categorized into four groups depending on birthweight. For a total of 378 chest and chest-abdomen radiographs, exposure parameters were recorded. Entrance surface dose (ESD) was estimated and dose-area product (DAP) was measured. Image quality evaluation was performed by two observers and was based on the visibility of certain anatomical features and catheters placed during treatment using a five-grade scale. ESD values increased with neonatal weight and demonstrated wide variation (16.4-76.9 microGy, mean 38.2 microGy). A wide variation was also observed in DAP values (1.2-15.0 mGycm2, mean 7.2 mGycm2). Image quality evaluation revealed the feasibility of achieving a diagnostically satisfactory image (score >70%) using both low and high tube voltage techniques, with the latter resulting in reduced ESDs. The majority of estimated ESDs are in accordance with the reference level of 50 microGy recommended by the National Radiological Protection Board for neonatal radiography. The results suggest that the use of high tube voltage techniques could result in further reductions in neonatal dose, without image quality degradation, underlying the requirement for establishing standard examination protocols for neonatal radiography with respect to neonatal weight.
Biotin is an important vitamin for cellular function and growth and, therefore, essential for fet... more Biotin is an important vitamin for cellular function and growth and, therefore, essential for fetal development. The fetus is exclusively dependent on maternal biotin supply. Since biotin is not produced within the body, maternal biotin levels depend on dietary intake. In order to investigate the biotin status of the human fetus, we measured the plasma biotin levels in 15 pregnant women and their fetuses who underwent amniocentesis and fetal blood sampling at 18-24 weeks of gestation for prenatal diagnosis of thalassemia. Maternal biotin was found to be 131 +/- (SD) 102 ng/l and fetal biotin 784 +/- 327 ng/l (p < 0.0001). Our findings are indicative of an active transport mechanism of biotin through the placenta in favor of the fetus.
Angiotensin-converting enzyme (ACE) gene contains a polymorphism consisting of either the presenc... more Angiotensin-converting enzyme (ACE) gene contains a polymorphism consisting of either the presence (I) or absence (D) of a 287-bp fragment. Recent studies have suggested that the I-allele may be associated with superior exercise endurance; respiratory muscle function may be similarly influenced. The pressure-time index of inspiratory muscles (PTImus) is a measure of the load-capacity ratio of the inspiratory muscles. The objective of this study was to determine whether infants homozygous for the I-allele have lower PTImus compared to infants homozygous for the D-allele or heterozygous I/D. One hundred thirty-two infants were studied. ACE genotyping was performed by polymerase chain reaction amplification, using DNA from peripheral blood. PTImus was calculated as (Pi(mean)/Pi(max)) × (T(i)/T(tot)), where Pi(mean) was the mean inspiratory pressure estimated from airway pressure, generated 100 ms after an occlusion (P(0.1)), Pi(max) was the maximum inspiratory pressure and T(i)/T(tot) ...
The objective of this study was to provide data on transcutaneous bilirubin (TcB) levels for the ... more 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. From September 2005 to August 2008, we obtained 14864 TcB measurements from 2818 healthy neonates (gestational age >or= 35 weeks and birth weight >or= 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. 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. We provide data on ...
Intrauterine growth restriction (IUGR) is associated with structural and functional cardiac alter... more Intrauterine growth restriction (IUGR) is associated with structural and functional cardiac alterations but the electrophysiological consequences of these disturbances remain unknown. To explore the distribution of ventricular repolarization and its relation to myocardial mechanics in newborns with IUGR. STUDY DESIGN, SUBJECTS AND OUTCOME MEASUREMENTS: Conventional and tissue Doppler echocardiographic data, and electrocardiographic parameters used to describe the distribution of ventricular repolarization (dispersion of QT [QTd] and JT [JTd]), were obtained on the second (D2) and fifth (D5) postnatal day and compared between 25 IUGR newborns and 25 matched-for-gestational age controls. IUGR was associated with relative interventricular septum hypertrophy, increased left ventricular (LV) E/E' ratio and higher LV myocardial performance index (MPI). On both study days, the IUGR infants presented higher QTd and JTd compared to controls (QTd-D2: 66±20 ms vs. 36±12 ms, P<0.001; JTd-D2: 54±13 ms vs. 34±9 ms, P<0.001; QTd-D5: 61±14 ms vs. 27±12 ms, P<0.001; JTd-D5: 54±13 ms vs. 27±9 ms, P<0.001). The association between QTd and LV E/E' (D2: regression coefficient beta 0.747, R(2) 0.585; D5: beta 0.843, R(2) 0.646) and QTd and MPI (D2: beta 0.680, R(2) 0.576; D5: beta 0.698, R(2) 0.650) was also significant (P<0.001 for all analyses). Our findings suggest that IUGR is associated with electrophysiological remodeling of the neonatal heart, a process which is closely related to the underlying alterations in ventricular mechanics and might predispose to adverse electrophysiological events.
To determine whether composite extubation indices can predict extubation outcome in preterm infan... more To determine whether composite extubation indices can predict extubation outcome in preterm infants. Prospective observational study. Level III neonatal intensive care unit. Fifty-six preterm infants cared for in the neonatal intensive care unit of a tertiary teaching hospital during 2007 and 2008. None. The study consisted of two parts. In the first part, different extubation indices were evaluated in a group of 28 neonates (derivation group). These indices included the diaphragmatic pressure-time index, the respiratory muscle pressure-time index, the maximal transdiaphragmatic pressure, the maximal inspiratory pressure, the airway pressure generated 100 milliseconds after an occlusion/maximal transdiaphragmatic pressure ratio, the airway pressure generated 100 milliseconds after an occlusion/maximal inspiratory pressure ratio, the tidal volume, and the respiratory rate to tidal volume ratio. After exploratory analysis, the best performing indices and the optimal threshold values to predict extubation outcome were selected. In the second part of the study, these indices were validated at the predetermined threshold values in an additional group of 28 preterm neonates (validation group). Four infants (14.3%) in the derivation group and four in the validation group (14.3%) failed extubation. Receiver operator characteristic curve analysis revealed that a diaphragmatic pressure-time index of ≤0.12, a respiratory muscle pressure-time index ≤0.10, a airway pressure generated 100 milliseconds after an occlusion/maximal transdiaphragmatic pressure of ≤0.14, and a airway pressure generated 100 milliseconds after an occlusion/maximal inspiratory pressure of ≤0.09 were the most accurate predictors of extubation outcome in the derivation group. In the validation group, a diaphragmatic pressure-time index of ≤0.12 and a respiratory muscle pressure-time index of ≤0.10 both had zero false-positive results, predicting with accuracy successful extubation. Composite extubation indices such as the diaphragmatic pressure-time index and the noninvasive respiratory muscle pressure-time index can accurately predict extubation outcome in preterm neonates.
Using a new computerized methodological procedure a separate analysis and a quantitative determin... more Using a new computerized methodological procedure a separate analysis and a quantitative determination of the viscous and elastic parameters of the scalp hair shaft were performed in 37 neonates of both sexes with a gestational age of 28-29 weeks (n = 16) and 39-40 weeks (n = 21), respectively. A statistically significant (p < 0.001) decrease in the values of
The goal was to develop a predictive nomogram, based on transcutaneous bilirubin (TcB) measuremen... more 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. A total of 10382 TcB measurements were performed with 2039 healthy neonates (gestational age of > or =35 weeks and birth weight of > or =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. 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. We provide a predictive TcB tool that could allow for a noninvasive, risk-based approach to neonatal hyperbilirubinemia.
The early postnatal cardiovascular consequences of intrauterine growth restriction (IUGR) have no... more 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. 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. 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. IUGR neonates present changes in cardiac morphology and subclinical myocardial dysfunction, which may result in an altered pattern of cardiovascular adaptation to extrauterine life.
In a special care baby unit, neonates, mainly premature, encounter serious to life-threatening di... more In a special care baby unit, neonates, mainly premature, encounter serious to life-threatening diseases, the timely diagnosis and treatment of which may require a large number of radiographs. Increased neonatal radiosensitivity and longer life expectancy increase the risk of radiation-induced cancer, which emphasizes the importance of minimizing dose while maintaining clinically satisfactory image quality. An optimization study on radiation dose and image quality in neonatal radiography is presented. Neonates were categorized into four groups depending on birthweight. For a total of 378 chest and chest-abdomen radiographs, exposure parameters were recorded. Entrance surface dose (ESD) was estimated and dose-area product (DAP) was measured. Image quality evaluation was performed by two observers and was based on the visibility of certain anatomical features and catheters placed during treatment using a five-grade scale. ESD values increased with neonatal weight and demonstrated wide variation (16.4-76.9 microGy, mean 38.2 microGy). A wide variation was also observed in DAP values (1.2-15.0 mGycm2, mean 7.2 mGycm2). Image quality evaluation revealed the feasibility of achieving a diagnostically satisfactory image (score >70%) using both low and high tube voltage techniques, with the latter resulting in reduced ESDs. The majority of estimated ESDs are in accordance with the reference level of 50 microGy recommended by the National Radiological Protection Board for neonatal radiography. The results suggest that the use of high tube voltage techniques could result in further reductions in neonatal dose, without image quality degradation, underlying the requirement for establishing standard examination protocols for neonatal radiography with respect to neonatal weight.
Biotin is an important vitamin for cellular function and growth and, therefore, essential for fet... more Biotin is an important vitamin for cellular function and growth and, therefore, essential for fetal development. The fetus is exclusively dependent on maternal biotin supply. Since biotin is not produced within the body, maternal biotin levels depend on dietary intake. In order to investigate the biotin status of the human fetus, we measured the plasma biotin levels in 15 pregnant women and their fetuses who underwent amniocentesis and fetal blood sampling at 18-24 weeks of gestation for prenatal diagnosis of thalassemia. Maternal biotin was found to be 131 +/- (SD) 102 ng/l and fetal biotin 784 +/- 327 ng/l (p < 0.0001). Our findings are indicative of an active transport mechanism of biotin through the placenta in favor of the fetus.
Angiotensin-converting enzyme (ACE) gene contains a polymorphism consisting of either the presenc... more Angiotensin-converting enzyme (ACE) gene contains a polymorphism consisting of either the presence (I) or absence (D) of a 287-bp fragment. Recent studies have suggested that the I-allele may be associated with superior exercise endurance; respiratory muscle function may be similarly influenced. The pressure-time index of inspiratory muscles (PTImus) is a measure of the load-capacity ratio of the inspiratory muscles. The objective of this study was to determine whether infants homozygous for the I-allele have lower PTImus compared to infants homozygous for the D-allele or heterozygous I/D. One hundred thirty-two infants were studied. ACE genotyping was performed by polymerase chain reaction amplification, using DNA from peripheral blood. PTImus was calculated as (Pi(mean)/Pi(max)) × (T(i)/T(tot)), where Pi(mean) was the mean inspiratory pressure estimated from airway pressure, generated 100 ms after an occlusion (P(0.1)), Pi(max) was the maximum inspiratory pressure and T(i)/T(tot) ...
The objective of this study was to provide data on transcutaneous bilirubin (TcB) levels for the ... more 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. From September 2005 to August 2008, we obtained 14864 TcB measurements from 2818 healthy neonates (gestational age >or= 35 weeks and birth weight >or= 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. 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. We provide data on ...
Intrauterine growth restriction (IUGR) is associated with structural and functional cardiac alter... more Intrauterine growth restriction (IUGR) is associated with structural and functional cardiac alterations but the electrophysiological consequences of these disturbances remain unknown. To explore the distribution of ventricular repolarization and its relation to myocardial mechanics in newborns with IUGR. STUDY DESIGN, SUBJECTS AND OUTCOME MEASUREMENTS: Conventional and tissue Doppler echocardiographic data, and electrocardiographic parameters used to describe the distribution of ventricular repolarization (dispersion of QT [QTd] and JT [JTd]), were obtained on the second (D2) and fifth (D5) postnatal day and compared between 25 IUGR newborns and 25 matched-for-gestational age controls. IUGR was associated with relative interventricular septum hypertrophy, increased left ventricular (LV) E/E' ratio and higher LV myocardial performance index (MPI). On both study days, the IUGR infants presented higher QTd and JTd compared to controls (QTd-D2: 66±20 ms vs. 36±12 ms, P<0.001; JTd-D2: 54±13 ms vs. 34±9 ms, P<0.001; QTd-D5: 61±14 ms vs. 27±12 ms, P<0.001; JTd-D5: 54±13 ms vs. 27±9 ms, P<0.001). The association between QTd and LV E/E' (D2: regression coefficient beta 0.747, R(2) 0.585; D5: beta 0.843, R(2) 0.646) and QTd and MPI (D2: beta 0.680, R(2) 0.576; D5: beta 0.698, R(2) 0.650) was also significant (P<0.001 for all analyses). Our findings suggest that IUGR is associated with electrophysiological remodeling of the neonatal heart, a process which is closely related to the underlying alterations in ventricular mechanics and might predispose to adverse electrophysiological events.
To determine whether composite extubation indices can predict extubation outcome in preterm infan... more To determine whether composite extubation indices can predict extubation outcome in preterm infants. Prospective observational study. Level III neonatal intensive care unit. Fifty-six preterm infants cared for in the neonatal intensive care unit of a tertiary teaching hospital during 2007 and 2008. None. The study consisted of two parts. In the first part, different extubation indices were evaluated in a group of 28 neonates (derivation group). These indices included the diaphragmatic pressure-time index, the respiratory muscle pressure-time index, the maximal transdiaphragmatic pressure, the maximal inspiratory pressure, the airway pressure generated 100 milliseconds after an occlusion/maximal transdiaphragmatic pressure ratio, the airway pressure generated 100 milliseconds after an occlusion/maximal inspiratory pressure ratio, the tidal volume, and the respiratory rate to tidal volume ratio. After exploratory analysis, the best performing indices and the optimal threshold values to predict extubation outcome were selected. In the second part of the study, these indices were validated at the predetermined threshold values in an additional group of 28 preterm neonates (validation group). Four infants (14.3%) in the derivation group and four in the validation group (14.3%) failed extubation. Receiver operator characteristic curve analysis revealed that a diaphragmatic pressure-time index of ≤0.12, a respiratory muscle pressure-time index ≤0.10, a airway pressure generated 100 milliseconds after an occlusion/maximal transdiaphragmatic pressure of ≤0.14, and a airway pressure generated 100 milliseconds after an occlusion/maximal inspiratory pressure of ≤0.09 were the most accurate predictors of extubation outcome in the derivation group. In the validation group, a diaphragmatic pressure-time index of ≤0.12 and a respiratory muscle pressure-time index of ≤0.10 both had zero false-positive results, predicting with accuracy successful extubation. Composite extubation indices such as the diaphragmatic pressure-time index and the noninvasive respiratory muscle pressure-time index can accurately predict extubation outcome in preterm neonates.
Using a new computerized methodological procedure a separate analysis and a quantitative determin... more Using a new computerized methodological procedure a separate analysis and a quantitative determination of the viscous and elastic parameters of the scalp hair shaft were performed in 37 neonates of both sexes with a gestational age of 28-29 weeks (n = 16) and 39-40 weeks (n = 21), respectively. A statistically significant (p < 0.001) decrease in the values of
The goal was to develop a predictive nomogram, based on transcutaneous bilirubin (TcB) measuremen... more 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. A total of 10382 TcB measurements were performed with 2039 healthy neonates (gestational age of > or =35 weeks and birth weight of > or =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. 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. We provide a predictive TcB tool that could allow for a noninvasive, risk-based approach to neonatal hyperbilirubinemia.
The early postnatal cardiovascular consequences of intrauterine growth restriction (IUGR) have no... more 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. 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. 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. IUGR neonates present changes in cardiac morphology and subclinical myocardial dysfunction, which may result in an altered pattern of cardiovascular adaptation to extrauterine life.
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