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| 2. |
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| 3. |
- Ågren, Johan
(author)
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Water transport through perinatal skin : Barrier function and aquaporin water channels
- 2003
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Doctoral thesis (other academic/artistic)abstract
- While constituting a well functioning interface with the aqueous environment in utero, the skin offers a poor barrier after very preterm birth. As a result, transepidermal water loss (TEWL) is high, a fact which has important clinical consequences in these infants. To investigate the transport of water through perinatal skin and the potential role of aquaporin (AQP), a water channel protein, in this process, we determined TEWL in a group of extremely preterm infants, and in an experimental rat model we analyzed the expression and distribution of AQP in perinatal skin in relation to TEWL, skin surface hydration and water content. The effects of antenatal corticosteroids (ANS) and of restricted intake of fluids and nutrients on barrier characteristics of the perinatal skin and its AQP expression were also studied.In infants born at 24 and 25 weeks of gestation TEWL was very high in the first days after birth and decreased with increasing postnatal age. At a postnatal age of 4 weeks, TEWL was still twice as high as previously reported in infants born at a gestational age of 25-27 weeks and four times higher than in infants born at term. In the rat model, immunohistochemical analysis revealed that AQP1 and AQP3 are abundantly expressed in the skin. AQP1 was expressed exclusively in dermal capillaries and AQP3 in basal layers of the epidermis. AQP1 and AQP3 mRNA as assessed by semiquantitative RT-PCR was higher in fetal than in adult skin. As in infants, TEWL and skin surface hydration were inversely related to gestational age in the rat. In preterm rat pups exposed to ANS, TEWL and skin surface hydration were lower than in unexposed controls, and AQP3 expression was selectively induced by ANS. In term newborn rat pups, restriction of fluid and nutrient intake resulted in a higher skin water content and higher TEWL early after birth, while at an age of 7 days TEWL was lower in fasting rat pups than in controls, although skin water content was still higher.To conclude, TEWL is very high in extremely preterm infants early after birth and then decreases at a slower rate than previously reported for a group of slightly more mature infants. This is the first time that the distribution and gene expression of AQP1 and AQP3 have been demonstrated in perinatal skin. The localization and expression of AQP in the skin might indicate that these water channels are involved in the regulation of skin hydration and transepidermal water transport in the fetus and newborn infant.
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| 4. |
- Agren, Johan, et al.
(author)
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Antenatal Corticosteroids and Postnatal Fluid Restriction Produce Differential Effects on AQP3 Expression, Water Handling, and Barrier Function in Perinatal Rat Epidermis
- 2010
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In: Dermatology research and practice. - : Hindawi Limited. - 1687-6113 .- 1687-6105.
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Journal article (peer-reviewed)abstract
- Loss of water through the immature skin can lead to hypothermia and dehydration in preterm infants. The water and glycerol channel aquaglyceroporin-3 (AQP3) is abundant in fetal epidermis and might influence epidermal water handling and transepidermal water flux around birth. To investigate the role of AQP3 in immature skin, we measured in vivo transepidermal water transport and AQP3 expression in rat pups exposed to clinically relevant fluid homeostasis perturbations. Preterm (E18) rat pups were studied after antenatal corticosteroid exposure (ANS), and neonatal (P1) rat pups after an 18 h fast. Transepidermal water loss (TEWL) and skin hydration were determined, AQP3 mRNA was quantified by RT-PCR, and in-situ hybridization and immunocytochemistry were applied to map AQP3 expression. ANS resulted in an improved skin barrier (lower TEWL and skin hydration), while AQP3 mRNA and protein increased. Fasting led to loss of barrier integrity along with an increase in skin hydration. These alterations were not paralleled by any changes in AQP3. To conclude, antenatal corticosteroids and early postnatal fluid restriction produce differential effects on skin barrier function and epidermal AQP3 expression in the rat. In perinatal rats, AQP3 does not directly determine net water transport through the skin.
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| 5. |
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| 6. |
- Farooqi, Aijaz, et al.
(author)
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Impact at Age 11 Years of Major Neonatal Morbidities in Children Born Extremely Preterm
- 2011
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In: Pediatrics. - : American Academy of Pediatrics (AAP). - 0031-4005 .- 1098-4275. ; 127:5, s. E1247-E1257
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Journal article (peer-reviewed)abstract
- BACKGROUND: Uncertainty continues regarding the extent to which neonatal morbidities predict poor long-term outcome and functional abilities in extremely preterm infants. OBJECTIVE: The goal of this study was to determine the impact of bronchopulmonary dysplasia (BPD), ultrasonographic signs of brain injury, and severe retinopathy of prematurity (ROP) on 11-year outcomes in infants born at < 26 weeks' gestation. METHODS: A total of 247 infants were born alive before 26 completed weeks of gestation from 1990 through 1992 in all of Sweden, and 98 (40%) survived to a postmenstrual age of 36 weeks. Main outcome measures were (1) poor outcome, defined as combined end point of death after 36 weeks' postmenstrual age or survival with at least 1 major disability at 11 years, and (2) consequences of chronic conditions in the survivors according to a validated instrument administered to parents. RESULTS: Brain injury and severe ROP but not BPD correlated independently with poor outcome at 11 years of age. Among children who were free from BPD, brain injury, and severe ROP, 10% had a poor outcome. Corresponding rates with any 1, any 2, and all 3 neonatal morbidities were 19%, 58%, and 80%, respectively. Multivariate analysis revealed that brain injury and severe ROP were associated with high rates of consequences of chronic conditions. CONCLUSIONS: In infants born extremely preterm who survive to a postmenstrual age of 36 weeks, severe ROP and brain injury separately predict the risk of death or major disability at 11 years of age. Thus, continued research to determine how to prevent these complications of prematurity is critical.
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| 7. |
- Farooqi, Aijaz, et al.
(author)
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Mental health and social competencies of 10- to 12-year-old children born at 23 to 25 weeks of gestation in the 1990s : a Swedish national prospective follow-up study.
- 2007
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In: Pediatrics. - : American Academy of Pediatrics (AAP). - 0031-4005 .- 1098-4275. ; 120:1, s. 118-133
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Journal article (peer-reviewed)abstract
- Abstract OBJECTIVE: We investigated a national cohort of extremely immature children with respect to behavioral and emotional problems and social competencies, from the perspectives of parents, teachers, and children themselves. METHODS: We examined 11-year-old children who were born before 26 completed weeks of gestation in Sweden between 1990 and 1992. All had been evaluated at a corrected age of 36 months. At 11 years of age, 86 of 89 survivors were studied and compared with an equal number of control subjects, matched with respect to age and gender. Behavioral and emotional problems, social competencies, and adaptive functioning at school were evaluated with standardized, well-validated instruments, including parent and teacher report questionnaires and a child self-report, administered by mail. RESULTS: Compared with control subjects, parents of extremely immature children reported significantly more problems with internalizing behaviors (anxiety/depression, withdrawn, and somatic problems) and attention, thought, and social problems. Teachers reported a similar pattern. Reports from children showed a trend toward increased depression symptoms compared with control subjects. Multivariate analysis of covariance of parent-reported behavioral problems revealed no interactions, but significant main effects emerged for group status (extremely immature versus control), family function, social risk, and presence of a chronic medical condition, with all effect sizes being medium and accounting for 8% to 12% of the variance. Multivariate analysis of covariance of teacher-reported behavioral problems showed significant effects for group status and gender but not for the covariates mentioned above. According to the teachers' ratings, extremely immature children were less well adjusted to the school environment than were control subjects. However, a majority of extremely immature children (85%) were functioning in mainstream schools without major adjustment problems. CONCLUSIONS: Despite favorable outcomes for many children born at the limit of viability, these children are at risk for mental health problems, with poorer school results.
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| 8. |
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| 9. |
- Jennische, Margareta, et al.
(author)
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School level at 10 years of age in children who required neonatal intensive care in 1980-1989
- 2006
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In: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 95:12, s. 1586-1593
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Journal article (peer-reviewed)abstract
- School level at age 10 was studied in two cohorts of children who had required neonatal intensive care (NIC): cohort 1, children born 1980-1985 (n=310); and cohort 2, children born 1986-1989 (n=245); and two control groups. More than 80% of all NIC children of both cohorts attended the appropriate mainstream grade 3 or 4; 12.9% of cohort 1 and 6.8% of cohort 2 were in mainstream grade 2. Six per cent of both cohorts received special education. Among very preterm children (23-31 gestational weeks), 73.5% of cohort 1 and 80.3% of cohort 2 attended grades 3 and 4, while 22.9% and 12.1%, respectively, were in grade 2. Assistance (remedial teaching, personal assistant or special teaching group) was given to 42.4% of cohort 1 in the mainstream (grades 2, 3 and 4) and to 38.2% of cohort 2 in the mainstream. In cohort 2, more very preterm girls than matched controls received assistance (p < 0.05); no corresponding difference was found in very preterm boys. Most children with congenital malformations received assistance in mainstream education or received special education. Conclusion: Most NIC children are in mainstream school classes at age 10. Twelve to 23% of very preterm children are 1 y behind. Many NIC children in the school mainstream need assistance at school, but the proportion of children in mainstream education increases markedly with time.
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| 10. |
- Johansson, Anders, 1972-, et al.
(author)
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Monitoring of heart and respiratory rates in newborn infants using a new photoplethysmographic technique
- 1999
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In: Journal of clinical monitoring and computing. - 1387-1307 .- 1573-2614. ; 15:7-8, s. 461-467
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Journal article (peer-reviewed)abstract
- Objective.A new photoplethysmographic (PPG) device for respiratoryand heart rate monitoring has been evaluated in the neonatal care units at theUniversity Children's Hospital of Uppsala, Sweden. The purpose of thisstudy was to compare this new device with more established techniques, i.e.,transthoracic impedance plethysmography (TTI) for monitoring of respiratoryrate and ECG for heart rate monitoring.Methods.Data were acquiredcontinuously for 8-hours in each of 6 neonates. The signals were analysed forperiods of 30 seconds, in which the heart and respiratory signals from the PPGdevice were compared with the ECG and the impedance plethysmogram.Results.The ECG recordings were of high quality in 77% of the analysed periods.In these periods, excluding periods (6%) disturbed by offset-adjustement ofthe PPG signal, the PPG heart signal included 1.1% (±0.7% SD) falsenegative beats and 0.9% (±0.6%) false positive beats. In periods withan impedance signal of high quality (29% of total time), the part of the PPGsignal synchronous with respiration included 2.7% (±1.1%) falsenegative breaths and 1.5% (±0.4%) false positive breaths. Here, 2% ofthe periods were discarded because of offset-adjustment. From the periods oflow signal quality, two other conclusions were drawn: 1) The impedance signalcontains more power in the respiratory range than the corresponding PPGrespiratory signal. 2) The breaths are easier to identify in the PPGrespiratory signal than in the impedance signal (subjective measure).Conclusions.Electrode and motion artefacts seem to disturb the ECGsignals and, particularly, the impedance signals. During periods of highquality ECG and impedance signals, the new optical device produces signals ofequal quality to these traditional methods, and is in some cases even better.The new device is non-invasive and has a small optical probe. These factors indicate further advantages of the photoplethysmographic method.
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| 11. |
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| 12. |
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| 13. |
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| 14. |
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| 15. |
- Kjällström, Barbro, et al.
(author)
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Clothing reduces evaporative water and heatloss in preterm infants
- 2011
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In: Journal of Neonatal-Perinatal Medicine. - 1934-5798. ; 4:2, s. 89-92
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Journal article (peer-reviewed)abstract
- Newborn preterm infants have large losses of fluid from their immature skin. To minimize fluid and heat loss and reduce the risk of dehydration and hypothermia, infants are routinely nursed in humidified and temperature-controlled incubators. The incubator care can be interrupted by periods of skin-to-skin care (STS). However, data are limited on how to reduce fluid and heat loss from very preterm infants during STS. To investigate the effect of clothing during STS we measured the evaporation of water from the surface of a body/skin model designed to simulate the skin temperature and ambient conditions of an extremely preterm infant during the first days of life. A semi-permeable membrane was placed on top of a water filled chamber heated to body temperature and kept in an incubator at relevant environmental conditions. The evaporation rate (ER) was determined by evaporimetry from the membrane surface alone or from the membrane covered with layers of fabric. The effect of fabric clothing was also determined in a group of extremely preterm infants during incubator care. The evaporation rate (ER) was 51 ± 2.7 g/m2 h from the membrane only. When layers of fabric were applied, ER decreased for each added layer. The ER and temperatures recorded in the model system were in the range relevant for preterm infants. In the infants, fabric clothing also resulted in a decreased ER. We conclude that layers of a simple cotton fabric provide a significant barrier to vapor diffusion thereby reducing evaporative loss of water and heat.
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| 16. |
- Macrae, Duncan J, et al.
(author)
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Inhaled nitric oxide therapy in neonates and children: reaching a European consensus.
- 2004
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In: Intensive care medicine. - : Springer Science and Business Media LLC. - 0342-4642 .- 1432-1238. ; 30:3, s. 372-80
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Journal article (peer-reviewed)abstract
- Inhaled nitric oxide (iNO) was first used in neonatal practice in 1992 and has subsequently been used extensively in the management of neonates and children with cardiorespiratory failure. This paper assesses evidence for the use of iNO in this population as presented to a consensus meeting jointly organised by the European Society of Paediatric and Neonatal Intensive Care, the European Society of Paediatric Research and the European Society of Neonatology. Consensus Guidelines on the Use of iNO in Neonates and Children were produced following discussion of the evidence at the consensus meeting.
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| 17. |
- Markasz, Laszlo, et al.
(author)
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The receptor for hyaluronan-mediated motility (RHAMM) expression in neonatal bronchiolar epithelium correlates negatively with lung air content
- 2018
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In: Early Human Development. - : Elsevier BV. - 0378-3782 .- 1872-6232. ; 127, s. 58-68
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Journal article (peer-reviewed)abstract
- Introduction: The receptor for hyaluronan-mediated motility (RHAMM) may have an important role in lung development. The aim of this study was to examine the expression of hyaluronan (HA) content and RHAMM during postnatal lung development by analyzing human lung specimens from ventilated newborn infants with a variety of lung diseases at different gestational and postnatal ages.Materials and methods: Ninety four patient samples were evaluated. RHAMM expression was studied by immunohistochemistry combined with digital image analysis. Cluster analysis was performed to find subgroups according to immuno-histological and clinical data. We present a computerized method that describes the air content of the lung by determining the fraction of the parenchyma-covered area in lung sections. HA content was estimated by radiometric assay.Results: The patients could be sorted into groups by hierarchical clustering. Five of six groups showed individual patterns according to RHAMM expression and HA content. Negative correlation was observed between air content and RHAMM expression in the bronchiolar epithelium irrespective of clustered groups. Lung hypoplasia appeared in two distinctive groups, with significant differences in lung development and RHAMM expression.Conclusions: RHAMM expression may show dynamic changes during pathological processes in the neonatal lung. The distribution of RHAMM in the lung tissue is heterogeneous with a predominance to the bronchiolar epithelium. We found a negative correlation between lung air content and RHAMM expression in bronchiolar epithelium.
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| 18. |
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| 19. |
- Rehncrona, S., et al.
(author)
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Apnea : Phrenic Nerve Stimulation
- 2009
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In: Textbook of Stereotactic and functional neurosurgery. - Heidelberg : Sringer Verlag. - 9783540707790 ; , s. 2991-2997
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Book chapter (other academic/artistic)
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| 20. |
- Rieger-Fackeldey, Esther, et al.
(author)
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Bronchopulmonary C-fibers modulate the breathing pattern in surfactant-depleted juvenile cats
- 2008
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In: Respiratory Physiology & Neurobiology. - : Elsevier BV. - 1569-9048 .- 1878-1519. ; 160:3, s. 341-349
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Journal article (peer-reviewed)abstract
- The aim of this study was to investigate the influence of nonmyelinated C-fibers on the breathing pattern by cooling the vagal nerves to temperatures at which myelinated nerve transmission from pulmonary stretch receptors is blocked (+7 degrees C) and further at which nonmyelinated fiber input is blocked (0 degrees C), in anaesthetized spontaneously breathing juvenile cats with normal (L(N)), surfactant-depleted (L(D)) and surfactant-treated (L(T)) lungs. In L(N), vagal cooling from +7 to 0 degrees C decreased respiratory frequency (f(R); -8%; p < 0.01), and increased tidal volume (V(T); +40%; p < 0.01). In the presence of shallow fast breathing in L(D), f(R) decreased (+38 to +7 degrees C: -26%; p < 0.015 and +7 to 0 degrees C: -24%; p < 0.001) and V(T) increased (+37%; p < 0.049 and +88%; p < 0.016). In L(T), f(R) decreased (+7 to 0 degrees C: -21%; p < 0.001), whereas V(T) remained the same at 0 degrees C (+12%; NS). These findings show for the first time that the activity of bronchopulmonary C-fibers have a prominent role in modulating the breathing pattern in juvenile cats with surfactant-depleted lungs.
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| 21. |
- Rieger-Fackeldey, Esther, et al.
(author)
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Inhibition of breathing after Surfactant Depletion is Achieved at a Higher Arterial PCO2 during Ventilation with Liquid than with Gas
- 2005
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In: Respiratory Research. - : Springer Science and Business Media LLC. - 1465-9921 .- 1465-993X. ; 6, s. 24-
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Journal article (peer-reviewed)abstract
- BackgroundInhibition of phrenic nerve activity (PNA) can be achieved when alveolar ventilation is adequate and when stretching of lung tissue stimulates mechanoreceptors to inhibit inspiratory activity. During mechanical ventilation under different lung conditions, inhibition of PNA can provide a physiological setting at which ventilatory parameters can be compared and related to arterial blood gases and pH.ObjectiveTo study lung mechanics and gas exchange at inhibition of PNA during controlled gas ventilation (GV) and during partial liquid ventilation (PLV) before and after lung lavage.MethodsNine anaesthetised, mechanically ventilated young cats (age 3.8 ± 0.5 months, weight 2.3 ± 0.1 kg) (mean ± SD) were studied with stepwise increases in peak inspiratory pressure (PIP) until total inhibition of PNA was attained before lavage (with GV) and after lavage (GV and PLV). Tidal volume (Vt), PIP, oesophageal pressure and arterial blood gases were measured at inhibition of PNA. One way repeated measures analysis of variance and Student Newman Keuls-tests were used for statistical analysis.ResultsDuring GV, inhibition of PNA occurred at lower PIP, transpulmonary pressure (Ptp) and Vt before than after lung lavage. After lavage, inhibition of inspiratory activity was achieved at the same PIP, Ptp and Vt during GV and PLV, but occurred at a higher PaCO2 during PLV. After lavage compliance at inhibition was almost the same during GV and PLV and resistance was lower during GV than during PLV.ConclusionInhibition of inspiratory activity occurs at a higher PaCO2 during PLV than during GV in cats with surfactant-depleted lungs. This could indicate that PLV induces better recruitment of mechanoreceptors than GV.
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| 22. |
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| 23. |
- Rieger-Fackeldey, Esther, et al.
(author)
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Pulmonary stretch receptor activity during partial liquid ventilation with different pressure waveforms
- 2020
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In: Respiratory Physiology & Neurobiology. - : Elsevier BV. - 1569-9048 .- 1878-1519. ; 276
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Journal article (peer-reviewed)abstract
- BACKGROUND: The aim of the present study was to investigate pulmonary stretch receptor activity (PSR) under different peak inspiratory pressures (PIPs) and inspiratory pressure waveforms during partial liquid (PLV) and gas ventilation (GV).METHODS: PSR instantaneous impulse frequency (PSRfimp) was recorded from single fibers in the vagal nerve during PLV and GV in young cats. PIPs were set at 1.2/1.8/2.2/2.7 kPa, and square and sinusoidal pressure waveforms were applied.RESULTS: PSRfimp at the start of inspiration increased with increasing PIPs, and was steeper and higher with square than with sinusoidal waveforms (p < 0.05). Total number of impulses, peak and mean PSRfimp were lower during PLV than GV at the lowest and highest PIPs (p < 0.025). Time to peak PSRfimp was shorter with square than with sinusoidal waveforms at all pressures and ventilations (p < 0.005). Irrespective of waveform, lower PIPs yielded lower ventilation during PLV.CONCLUSION: As assessed by PSRfimp, increased PIPs do not expose the lungs to more stretching during PLV than during GV, with only minor differences between square and sinusoidal waveforms.
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| 24. |
- Rieger-Fackeldey, Esther, 1960-
(author)
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Regulation of Breathing under Different Pulmonary Conditions
- 2004
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Doctoral thesis (other academic/artistic)abstract
- The breathing pattern of preterm infants is immature and is associated with a variety of reflexes. In a patient on the ventilator these reflexes interfere with spontaneous breathing. A better understanding of the immature control of breathing could lead to further improvements in ventilatory techniques. This thesis concerns studies of pulmonary stretch receptor (PSR) and phrenic nerve activity as part of the regulation of breathing in an animal model.During assist/control ventilation with three different inspiratory pressure waveforms in animals with healthy lungs, squarewave pressure waveform strongly inhibits spontaneous inspiratory activity.During partial liquid ventilation (PLV) in animals with healthy lungs, all PSRs studied maintained their phasic character, with increased impulse frequency during inspiration. PSR activity was not higher during PLV than during gas ventilation (GV), indicating that there was no extensive stretching of the lung during PLV.During proportional assist ventilation (PAV) the applied airway pressure is servo-controlled proportionally to the ongoing breathing effort, thereby interacting with the activity of PSRs. Peak PSR activity was higher and occurred earlier during PAV than during CPAP. The regulation of breathing is maintained during PAV in surfactant-depleted animals before and early after surfactant instillation, with a higher ventilatory response and a lower breathing effort than during CPAP in both conditions.Both lung mechanics and gas exchange influence the regulation of breathing. Inhibition of inspiratory activity occurred at a lower arterial pH and a higher PaCO2 during PLV than during GV in animals with surfactant-depleted lungs, which might be related to recruitment of a larger number of pulmonary stretch receptors during PLV.In summary, selected aspects of the regulation of breathing were studied in an animal model with different ventilatory techniques under different lung conditions similar to those that can occur in infants.
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| 26. |
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| 27. |
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| 28. |
- Sedin, Gunnar, et al.
(author)
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Kuvösvård
- 2008
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In: Neonatologi. - Lund : Studentlitteratur. - 9789144046433 ; , s. 439-439
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Book chapter (pop. science, debate, etc.)
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| 29. |
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| 31. |
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| 38. |
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| 39. |
- Sindelar, Richard, et al.
(author)
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Effects of the inspiratory pressure waveform during patient-triggered ventilation on pulmonary stretch receptor and phrenic nerve activity in cats
- 2001
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In: Critical Care Medicine. - 0090-3493 .- 1530-0293. ; 29:6, s. 1207-1214
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Journal article (peer-reviewed)abstract
- Objective:To examine the effects of square wave, sinusoidal, and linear inspiratory pressure waveforms during pressure-controlled assist/control ventilation on the firing pattern of pulmonary stretch receptors and phrenic nerve activity.Design:Experimental, comparative study.Setting:Research laboratory at a university biomedical center.Subjects:Nine anesthetized, endotracheally intubated young cats (2.5–3.4 kg).Intervention:With interposed periods of continuous positive airway pressure (0.2 kPa), each cat was exposed to periods of assist/control ventilation with three different pressure waveforms, where the peak inspiratory pressure (0.74 ± 0.13 kPa), end-expiratory pressure (0.2 ± 0.02 kPa), and tidal volume (14.9 ± 5.22 mL/kg) were kept constant. Preset controlled ventilator rate was set below the rate of spontaneous breathing, and the mechanical inflation time equaled the inspiratory time during spontaneous breathing on continuous positive airway pressure.Measurements and Main Results:Respiratory rate and arterial blood gases did not change between the three pressure waveforms during assist/control ventilation. Peak pulmonary stretch receptor activity was lower and mean phrenic nerve activity higher during continuous positive airway pressure than during assist/control ventilation (p < .05). Peak inspiratory pulmonary stretch receptor activity was the same with all three pressure waveforms (82 ± 17 impulses·sec-1) but occurred earlier with square wave than with sinusoidal or linear pressure waveforms (p < .05). The total number of impulses in the phrenic nerve activity burst was smaller with square wave than with the other two pressure waveforms (0.21 ± 0.17 vs. 0.33 ± 0.27 and 0.42 ± 0.30 arbitrary units;p < .05), and the phrenic nerve activity burst duration was shorter with square wave (1.10 ± 0.45 vs. 1.54 ± 0.36 and 1.64 ± 0.25 secs;p < .05).Conclusion:Square wave pressure waveform during pressure-controlled assist/control ventilation strongly inhibits spontaneous inspiratory activity in cats. One mechanism for this inhibition is earlier and sustained peak pulmonary stretch receptor activity during inspiration. These findings show that differences in inspiratory pressure waveforms influence the spontaneous breathing effort during assist/control ventilation in cats.
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| 40. |
- Sindelar, Richard, et al.
(author)
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Maintained inspiratory activity during proportional assist ventilation in surfactant-depleted cats early after surfactant instillation : phrenic nerve and pulmonary stretch receptor activity.
- 2006
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In: Respir Res. - 1465-993X. ; 7, s. 38-
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Journal article (peer-reviewed)abstract
- BACKGROUND: Inspiratory activity is a prerequisite for successful application of patient triggered ventilation such as proportional assist ventilation (PAV). It has recently been reported that surfactant instillation increases the activity of slowly adapting pulmonary stretch receptors (PSRs) followed by a shorter inspiratory time (Sindelar et al, J Appl Physiol, 2005 [Epub ahead of print]). Changes in lung mechanics, as observed in preterm infants with respiratory distress syndrome and after surfactant treatment, might therefore influence the inspiratory activity when applying PAV early after surfactant treatment. OBJECTIVE: To investigate the regulation of breathing and ventilatory response in surfactant-depleted young cats during PAV and during continuous positive airway pressure (CPAP) early after surfactant instillation in relation to phrenic nerve activity (PNA) and the activity of PSRs. METHODS: Seven anesthetized, endotracheally intubated young cats were exposed to periods of CPAP and PAV with the same end-expiratory pressure (0.2-0.5 kPa) before and after lung lavage and after surfactant instillation. PAV was set to compensate for 75% of the lung elastic recoil. RESULTS: Tidal volume and respiratory rate were higher with lower PaCO2 and higher PaO2 during PAV than during CPAP both before and after surfactant instillation (p < 0.05; both conditions). As an indicator of breathing effort, esophageal deflection pressure and PNA were lower during PAV than during CPAP in both conditions (p < 0.02). Peak PSR activity was higher and occurred earlier during PAV than during CPAP (p < 0.01), and correlated linearly with PNA duration in all conditions studied (p < 0.001). The inspiratory time decreased as tidal volume increased when CPAP was changed to PAV, with the highest correlation observed after surfactant instillation (r = -0.769). No apneic periods could be observed. CONCLUSION: PSR activity and the control of breathing are maintained during PAV in surfactant-depleted cats early after surfactant instillation, with a higher ventilatory response and a lower breathing effort than during CPAP.
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| 41. |
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| 42. |
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| 43. |
- Wennergren, Göran, 1947, et al.
(author)
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The epidemiology of sudden infant death syndrome and attacks of lifelessness in Sweden.
- 1987
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In: Acta paediatrica Scandinavica. - 0001-656X. ; 76:6, s. 898-906
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Journal article (peer-reviewed)abstract
- Infants who died showing the syndrome of sudden infant death (SIDS) and infants who survived attacks of lifelessness (AL) were examined in a prospective epidemiological multicentre study over 24 months covering close to 40% of all births in Sweden. Seventy SIDS cases and 34 cases of AL were observed, giving an incidence for SIDS of 0.94/1000 and for AL of 0.46/1000. This SIDS incidence is higher than that observed during the seventies. The boy/girl ratio was 1.4:1 for SIDS and 1.6:1 for AL. The age distribution for AL resembled that for SIDS. Similarities were also seen with regard to place of occurrence. Sixty per cent of the SIDS cases occurred during the daytime/evening. Twenty-nine per cent of the infants with AL had more than one apneic spell during the three-day-period around the attack, indicating a period of respiratory instability, but only 12% had such spells later on. None of the infants who had had AL died from SIDS. The possible relationship between AL and SIDS is discussed.
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| 44. |
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| 45. |
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| 46. |
- Ågren, Johan, et al.
(author)
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Transepidermal water loss in developing rats : Role of aquaporins in the immature skin
- 2003
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In: Pediatric Research. - 0031-3998 .- 1530-0447. ; 53:4, s. 558-565
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Journal article (peer-reviewed)abstract
- In the extremely preterm infant, high transepidermal water loss (TEWL) can result in severe dehydration. TEWL has been attributed to the structural properties of the epidermis but might also be influenced by mechanisms that facilitate water transport. To investigate whether aquaporins (AQP) may be involved in the extreme losses of water through immature skin, we examined the presence and cellular distributions of AQP-1 and AQP-3 in embryonic and adult rat skin by immunohistochemistry. The expression of AQP mRNA in skin was analyzed with the use of semiquantitative reverse transcription-PCR. In rat pups of different embryonic (E) and postnatal (P) ages (days), TEWL and skin hydration were measured. AQP-1 was detected in dermal capillaries, and AQP-3 was abundant in basal epidermal layers. Both AQP displayed several times higher expression in embryonic than in adult skin. TEWL was highest at embryonic day 18 (E18) (133 +/- 18 g/m2h) and lower at E20 (25 +/- 1 g/m2h) and P4 (9 +/- 2 g/m2h). Skin hydration measured as skin electrical capacitance paralleled TEWL, being highest in fetal skin (794 +/- 15 pF at E18) and decreasing to 109 +/- 11 pF at E20 and to 0 +/- 0 pF at P4. We conclude that, as in infants, water loss through the skin of rats decreases markedly with maturation during the perinatal period. The expression and cellular localization of the AQP are such that they might influence skin hydration and water transport and contribute to the high losses of water through the immature skin.
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| 47. |
- Ågren, Johan, et al.
(author)
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Vätskebalans
- 2008
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In: Neonatologi. - Lund : Studentlitteratur. - 9789144046433 ; , s. 159-165
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Book chapter (pop. science, debate, etc.)
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