Unchanged heart rate-respiratory frequency ratio in preterm infants during spontaneous arousals.

AIM: To find out whether a correlation of heart rate (HR) and respiratory frequency (RF) defined as HR-RF-ratio (HRR) may be helpful to identify arousals in term and preterm infants. METHODS: Polygraphic recordings were performed in 25 term infants (gestational age 40.1 +/- 1.1 weeks) and 25 preterm infants (gestational age 31.1 +/- 1.3 weeks) during undisturbed daytime sleep. Arousals were scored as suggested by the 'International Paediatric Work Group on Arousals' and divided into cortical arousals and subcortical arousals. HRR was defined as HR over RF. Arousals were compared to a 30-sec period preceding an arousals. RESULTS: Two hundred arousals were scored (100 cortical arousals and 100 subcortical arousals). HRR increased during arousals in term infants (p < 0.001). This was true for cortical arousals (p < 0.001) and subcortical arousals (p < 0.05) of term infants. In contrast, in preterm infants HRR remained unchanged during cortical arousals and subcortical arousals. CONCLUSION: An increase of HRR during arousals is a simple parameter to identify arousals in term infants, but not in preterm infants suggesting that an unchanged HRR might be an indicator of an immature arousal response.

Is bladder voiding in sleeping preterm infants accompanied by arousals?

BACKGROUND: As it has been reported that bladder voiding in sleeping full-term infants is consistently accompanied by a cortical arousal, it was the aim of the present study to find out whether this could also hold true for preterm infants. METHODS: Polygraphic recordings were performed in 21 healthy preterm infants (10 female). The infants' gestational age at birth was 31+/-2.7 weeks and postnatal age at study entry was 26+/-8 days (mean+/-standard deviation). Bladder voiding was recorded by an adapted enuresis detector which was connected to the polygraphic computer unit. Arousals were defined as suggested by the International Paediatric Work Group on Arousals. RESULTS: Bladder voiding was recorded 50+/-7 min after sleep onset and occurred during quiet sleep (QS) only. Heart rate (HR), respiratory frequency (RF) and electroencephalographic (EEG) frequency did not change during bladder voiding. Body movements were recorded in 52% of all preterm infants. CONCLUSION: We found that bladder voiding was not accompanied by arousals, suggesting that the arousal process in preterm infants may be delayed due to immaturity.

A portable real-time in situ gamma-ray analysis system.

A portable CeBr3 based gamma-ray detection system was designed and built for rapid turnaround, high throughput, real-time, and in situ sample analysis. The new technique allows automated data transmission from the field unit to a central laboratory controller to ensure laboratory quality of the data collected by field users without gamma-ray spectroscopy expertise. The method validation data indicates that the system's data quality objectives are adequate for radiological or nuclear emergency response or targeted surveillance programs where gamma-ray analysis is needed.

Comparison of heart rate responses during cortical and subcortical arousals in term and preterm infants.

The aim of this study was to determine whether prematurity affects heart rate responses during spontaneous arousals. Polygraphic recordings were performed during undisturbed daytime naps in 35 preterm infants (gestational age at birth 32+/-2 weeks) and 35 term infants. Arousals were scored according to the recommendations of the International Paediatric Work Group on Arousals and categorized either as cortical arousals (CA) or subcortical arousals (SCA). Heart rate (HR) and respiratory frequency (RF) were measured during arousal and during the 10-s and 30-s period before and after arousal. Changes in HR and RF were expressed as the percentage of modification normalized for the 30-s period preceding arousal. Altogether, 122 arousals in preterm infants (66 CA, 56 SCA) and 105 arousals in term infants (57 CA, 48 SCA) were scored. Mean duration of the arousal period was 9+/-4 s and 8+/-3 s, respectively. In term infants, a significant increase in HR during arousal could be shown (11.3+/-8.2%; p<0.001), whereas this increase was significantly greater during CA compared to SCA (13.7+/-6.2% versus 8.4+/-9.4%; p<0.001). In contrast, HR decreased during arousal in preterm neonates (-3.9+/-19.3%; p<0.05). These findings suggest that cardiovascular control seems to be maturationally delayed in preterm infants, which may contribute to their increased risk for Sudden Infant Death Syndrome (SIDS).

Cerebral hemodynamics during arousals in preterm infants.

The aim of the study was to evaluate potential changes of cerebral blood volume (CBV) related to arousals in preterm infants. As arousals are known to change different physiological parameters, it was postulated that this could also hold true for CBV. Polygraphic recordings were performed in 38 preterm infants (18 female, 20 male). The infants' gestational age at birth was 32.0+/-2.3 weeks, postconceptional age was 35.1+/-1.2 weeks and postnatal age at study entry was 24.3+/-2.9 days, birth weight was 1793+/-527 g and actual weight at study entry was 2011+/-324 g [mean (+/- standard deviation)]. CBV was measured using near infrared spectroscopy. Arousals were scored due to the guidelines of the "International Paediatric Work Group on Arousals" and categorized as either cortical (CA) or subcortical arousals (SCA). Altogether, 122 arousals (66 CA, 56 SCA) were scored. According to sleep stage, 77 arousals were analyzed in active sleep, 23 in quiet sleep and 22 in intermediate sleep. Mean duration of arousals was 8.8+/-0.3 s. CBV, cerebral vascular oxygenation and the balance between oxygen delivery and oxygen consumption remained constant during arousals in preterm infants. This was demonstrated for both CA and SCA and was independent of sleep stage, suggesting that the impact of arousals in stable preterm infants is too small to alter cerebral vascular autoregulation.

Thrombophilic polymorphisms--factor V Leiden, prothrombin G20210A, and methylenetetrahydrofolate reductase C677T mutations--and preterm birth.

AIM OF THE STUDY: To evaluate the influence of three common thrombophilic polymorphisms, factor V Leiden (FV), prothrombin G20210A (PT), and methylenetetrahydrofolate reductase (MTHFR) C677T mutations, on preterm birth of unknown cause. PATIENTS AND METHODS: A single-centre case-control study of women with preterm infants < or =35 weeks of gestation, in whom obvious maternal, uterine, and fetal causes responsible for preterm birth were excluded (n = 35). The controls were 54 women with term infants hospitalised in the same ward. RESULTS: There were no significant differences between the groups of mothers in history of fetal loss, venous or familial thrombosis, or previous preterm birth. FV was found in 8.6% of the cases, PT in 5.7%, and MTHFR mutation (homozygous) in 4.8% compared with 5.4% (p=0.292, OR 1.594, CI95% 0.303-8.384), 7.4% (p=0.379, OR 0.758, CI95% 0.131-4.374), and 4.5% (p = 0.485, OR 1.050, CI95% 0.090-12.276), respectively, in the controls. Differences in the three thrombophilic polymorphisms in the two groups of infants were also not significant. CONCLUSION: We could not demonstrate a distinct association between these thrombophilic polymorphisms and preterm birth.

Delayed meconium passage in small vs. appropriate for gestational age preterm infants: management and short-term outcome.

OBJECTIVE: Delayed passage of stool is a result of both gestational immaturity and illness severity. Small for gestational age (SGA) preterm infants are at high risk of gastrointestinal (GI) complications. We aimed to analyse the effects of a strict nutrition and stool protocol on GI problems in SGA compared to appropriate for gestational age (AGA) preterm infants. METHODS: Retrospective cohort analysis including all preterm infants with delayed meconium passage hospitalized at the Neonatal Intensive Care Unit of the Medical University of Graz, Austria. Infants were identified by a local data system and by the use of a strict feeding and stool protocol between 2001 and 2009. Main outcome parameters included neonatal morbidity, surgical intervention and mortality. FINDINGS: Twenty-six SGA (median GA 28.6 weeks, birth weight 825 grams, 46% males) were compared to 101 AGA (median GA 28.4 weeks, birth weight 1168 grams, 55% males) preterm infants. Clinical signs of delayed meconium passage did not differ significantly between groups. Differences regarding percentage of necrotizing enterocolitis, ileus, spontaneous intestinal perforation, and surgical intervention did not differ between groups. Mortality rate was significantly higher in SGA (11.5%) compared to AGA (2.9%) infants (P=0.03). CONCLUSION: Despite similar morbidity SGA infants exhibited higher lethal complication rates following delayed meconium passage compared to AGA infants.

Cost-effectiveness of palivizumab for respiratory syncytial virus infection in high-risk children, based on long-term epidemiologic data from Austria.

OBJECTIVE: To assess the cost-effectiveness of palivizumab, a monoclonal antibody against respiratory syncytial virus (RSV), in infants at high risk for severe RSV lower respiratory tract infection, such as premature infants, infants with bronchopulmonary dysplasia, and those with congenital heart disease, based on long-term epidemiologic data from Austria. METHODS: A decision-tree model was used, and the analysis was based on a lifetime follow-up investigating cost-effectiveness of palivizumab versus no RSV infection prevention. The primary perspective of the study was that of the healthcare system, the second that of society. Cost and effects were discounted by 5%. The base case analysis included only direct medical costs, and a scenario analysis included various indirect costs. RESULTS: Analyses were based on epidemiologic data on a total of 1579 children hospitalized because of RSV lower respiratory tract infection during 16 seasons. The incremental cost-effectiveness ratio for the first outcome measure (life years gained) amounted to discounted costs of €34,956 (for all preterm infants), €35,056 (for < 33 weeks' gestational age [wGA] infants), €35,233 (for 33-35 wGA infants), €35,611 (for infants with bronchopulmonary dysplasia), and €8956 (for infants with congenital heart disease). Use of palivizumab compared with no prophylaxis had an incremental cost-utility ratio of €26,212, €26,292, €24,392, €24,654, and €8484, respectively, per quality-adjusted life years. Results from the society perspective were more cost-effective in all study populations. An additional scenario analysis with 7 injections for the 33 to 35 wGA group revealed cost-effectiveness as well. CONCLUSIONS: Our results based on nationwide long-term epidemiologic data suggest that palivizumab is cost-effective in prevention of RSV disease in high-risk infants.

Prematurity: influence on mother's locus of control.

The aim of the present study was to compare the beliefs of mothers of term infants with the beliefs of mothers of preterm infants in regards to their locus of control mainly influencing their personal health and well-being. Mother's beliefs regarding the level of internal (self), social external (other individuals) and fatalistic external control (e.g. chance, destiny, and religion) were assessed while mothers were admitted to hospital postnatally. Thirty-five mothers of preterm infants under 32 weeks of gestation, and 35 mothers of term infants (≥ 37 weeks of gestation) were included and participated within the first three days after delivery. Between the group of mothers of term infants and the group of mothers of preterm infants there was a significant difference in the level of fatalistic external control of health and disease they experienced. Mother's beliefs regarding internal and social external control did not differ between the two groups. When dealing with the mothers of preterm infants one should consider their strong beliefs that health and disease are largely dependent on fatalistic external factors. This might help to improve mother-child interaction and as a consequence also neurobehavioral development of the preterm infant.

Tilting the head changes cerebral haemodynamics in neonates.

BACKGROUND: Tilting only the head influences cerebral haemodynamics in term and preterm neonates. OBJECTIVE: To evaluate near-infrared spectroscopy (NIRS) as a method to detect changes of cerebral oxygenated (HbO(2)) and deoxygenated haemoglobin (Hb) and 'cerebral tissue-oxygenation-index' (cTOI) while tilting. Furthermore to investigate whether the comparison of cTOI and 'cerebral mixed venous oxygen saturation' (tiltSvO(2)), calculated out of the increase of HbO(2) and Hb, improves reproducibility. METHODS: During five 'reapplication' periods of NIRS optodes on the left forehead of 40 neonates, five tilting manoeuvres of the head were performed. Changes of NIRS parameters during tilting were analysed. The first quality criterion was defined by a linear increase of total haemoglobin (HbT; r(2) > 0.95). The second quality criterion was: cTOI > tiltSvO(2) (= cTOI - tiltSvO(2)> 0). Analysis of variance components and comparison of mean of standard deviations were applied to data after introduction of each quality criterion. RESULTS: While HbO(2), Hb and HbT showed a linear increase in all neonates during tilting, cTOI did not change. With the introduction of the second criterion, mean cTOI increased from 73.7 ± 6.9 to 75.1 ± 6.9%, mean tiltSvO(2) decreased from 72.6 ± 7.1 to 65.3 ± 6.9% and mean of standard deviations of both parameters decreased. The analysis of variance components showed no significant change. CONCLUSION: A tilting-down manoeuvre of the head of term and preterm neonates can cause an increase of HbO(2), Hb and HbT. tiltSvO(2) can be calculated out of these changes. By introducing two quality criteria, reproducibility of cerebral NIRS measurements (cTOI and tiltSvO(2)) improved.

Risk of concurrent bacterial infection in preterm infants hospitalized due to respiratory syncytial virus infection.

OBJECTIVE: To evaluate the risk of concurrent bacterial infection in preterm infants hospitalized due to respiratory syncytial virus (RSV) disease. PATIENTS AND METHODS: Retrospective cohort analysis of all infants hospitalized due to RSV infection between January 1, 2001 and July 31, 2005. Patients were identified by ICD-10 diagnosis of RSV infection including codes J21.0, J21.9, J12.1, J20.5 and B97.4. Medical charts were reviewed and RSV infection had to be confirmed by positive antigen detection test on nasopharyngeal aspirates. RESULTS: A total of 464 infants had been hospitalized due to RSV infection and 42 (9.1%) were born<37 weeks of gestational age. Concurrent bacterial infections were diagnosed by either positive blood or urine cultures, stool culture, tracheal aspirates or smears in 4 of 42 preterm (9.5%) compared to 13 of 422 term (3.1%) infants (p=0.017, RR 3.092, CI 95% 1.251-7.641). Excluding the infants admitted to the intensive care unit (ICU) the total rate of bacterial co-infection was 1.9%. Ten of 42 preterm (23.8%) compared to 25 of 422 term (5.2%) infants were referred to ICU (p<0.001, RR 3.349, CI 95% 1.882-5.959). All preterm infants had pneumonia, and isolates were Streptococcus pneumoniae, Chlamydia pneumoniae and Streptococcus pneumoniae with Haemophilus influenzae. Mean length of stay in preterm infants with bacterial co-infection was 22.3 days compared to 10.3 days without bacterial co-infection (p<0.006). CONCLUSION: The overall low risk of concurrent bacterial infection was significantly increased in preterm infants associated with prolonged hospitalization and ICU admission.

Bladder voiding in sleeping infants is consistently accompanied by a cortical arousal.

The aim of the study was to find out whether bladder voiding in healthy sleeping infants was accompanied by any arousal reaction. Polygraphic recordings were performed in 21 healthy infants (11 female) born at term. The infants' age at study entry was 42 +/- 4 days and actual body weight was 4852 +/- 689 g (mean +/- SD). Bladder voiding was recorded by an adapted enuresis detector which was connected to the polygraphic computer unit. Arousals were defined as suggested by the 'International Paediatric Work Group on Arousals'. Awakenings were excluded from the study. Bladder voiding was recorded at a mean time of 68 +/- 7 min after the infant had fallen asleep and occurred during quiet sleep (QS). Electroencephalogram frequency (P < 0.01) and heart rate (P < 0.05) were higher during the 5-s period before and after bladder voiding when compared with a 30-s interval before voiding. Furthermore, bladder voiding was accompanied by body movements in all infants. Respiratory frequency did not change significantly. We could demonstrate for the first time in sleeping infants, that bladder voiding during QS was accompanied by a cortical arousal.

Does bladder voiding during sleep and wakefulness change the behavioural state of infants?

AIM: To evaluate whether bladder voiding in healthy infants is accompanied by body movements or any changes in heart rate (HR), respiratory frequency (RF) or electroencephalogram (EEG) frequency during sleep and during wakefulness. METHODS: Polygraphic recordings were performed on 33 healthy infants (17 female) born at term. The infants' age at study entry was 41+/-10 d, and actual body weight was 4876+/-403 g (mean+/-SD). Bladder voiding was recorded by an adapted enuresis detector connected to the polygraphic computer unit. RESULTS: Awakening was observed in 12 (36%) infants 77+/-9 s before bladder voiding. Twenty-one infants (64%) continued sleeping during bladder voiding. In sleeping infants, bladder voiding occurred during non-REM sleep only, and was accompanied by a cortical arousal. During wakefulness, RF was lower, and HR and EEG frequency were higher, but stayed constant during bladder voiding. CONCLUSION: Our observations demonstrate that bladder voiding in healthy infants during sleep is accompanied by body movements and changes in HR and EEG frequency, indicating cortical arousals, whereas during wakefulness these changes cannot be observed.