Pulmonary stretch receptor activity during partial liquid ventilation with different pressure waveforms.

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 (PSRf) was recorded from single fibers in the vagal nerve during PLV and GV in young cats. PIPs were set at 1.

The receptor for hyaluronan-mediated motility (RHAMM) expression in neonatal bronchiolar epithelium correlates negatively with lung air content.

Introduction: Hyaluronan (HA) and the receptor for hyaluronan-mediated motility (RHAMM) may play an important role in lung development. We examined the expression of HA content and RHAMM during postnatal lung development by analyzing human lung specimens from newborn infants with a variety of lung diseases at different gestational (GA) and postnatal (PNA) ages.

Materials And Methods: Ninety-four patients were evaluated.

Impact at age 11 years of major neonatal morbidities in children born extremely preterm.

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.

Antenatal Corticosteroids and Postnatal Fluid Restriction Produce Differential Effects on AQP3 Expression, Water Handling, and Barrier Function in Perinatal Rat Epidermis.

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.

Bronchopulmonary C-fibers modulate the breathing pattern in surfactant-depleted juvenile cats.

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.

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.

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.

School level at 10 years of age in children who required neonatal intensive care in 1980-1989.

Unlabelled: 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.

Chronic conditions, functional limitations, and special health care needs in 10- to 12-year-old children born at 23 to 25 weeks' gestation in the 1990s: a Swedish national prospective follow-up study.

Background: Children born extremely immature (gestational age < 26 weeks' gestation) increasingly reach school age. Information on their overall functioning and special health care needs is necessary to plan for their medical and educational services. This study was undertaken to examine neurosensory, medical, and developmental conditions together with functional limitations and special health care needs of extremely immature children compared with control subjects born at term.

Growth in 10- to 12-year-old children born at 23 to 25 weeks' gestation in the 1990s: a Swedish national prospective follow-up study.

Background: Knowledge of long-term growth of extremely preterm infants in relation to gestational age is incomplete, and there are concerns regarding their poor growth in early childhood. As part of a longitudinal study of a national cohort of infants born at <26 weeks' gestation (extremely immature), growth development from birth to the age of 11 years was examined, and correlates of growth attainment were analyzed.

Methods: Two hundred forty-seven extremely immature children were born alive from April 1990 through March 1992 in the whole of Sweden, and 89 (36%) survived.

Ambient humidity influences the rate of skin barrier maturation in extremely preterm infants.

Objectives: To test the hypothesis that the level of relative humidity (RH) in which preterm infants are nursed might influence their postnatal skin maturation.

Study Design: In 22 preterm infants (GA 23-27 weeks), transepidermal water loss (TEWL) was determined at postnatal ages (PNA) of 0, 3, 7, 14, and 28 days. At a PNA of 7 days, the infants were randomized to care at either 50% or 75% RH.

Water and heat--the priority for the newborn infant.

Maintaining fluid and heat balance is of vital importance to the newborn infant. At birth, the infant is exposed to a cold and dry environment, and preterm neonates in particular, are then at risk of dehydration and hypothermia. These conditions may have serious consequences and significantly influence mortality and morbidity.

Maintained inspiratory activity during proportional assist ventilation in surfactant-depleted cats early after surfactant instillation: phrenic nerve and pulmonary stretch receptor activity.

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.

Surfactant replacement partially restores the activity of pulmonary stretch receptors in surfactant-depleted cats.

Single units of slowly adapting pulmonary stretch receptors (PSRs) were investigated in anesthetized cats during spontaneous breathing on continuous positive airway pressure (2-5 cmH2O), before and after lung lavage and then after instillation of surfactant to determine the PSR response to surfactant replacement. PSRs were classified as high threshold (HT) and low threshold (LT), and their instantaneous impulse frequency (f imp) was related to transpulmonary pressure (Ptp) and tidal volume (Vt). Both the total number of impulses and maximal f imp of HT and LT PSRs decreased after lung lavage (55 and 45%, respectively) in the presence of increased Ptp and decreased Vt.

Preterm birth contributes to increased vascular resistance and higher blood pressure in adolescent girls.

Preterm birth might induce permanent changes in vascular structure and function as well as in blood pressure. To elucidate this hypothesis and underlying mechanisms in girls born before term, the authors correlated neonatal data, including estradiol levels, with vascular function and structure and with blood pressure after puberty. In a case-control study design, 34 girls born before term and 32 gender- and age-matched control infants born at term were included.

Inhibition of breathing after surfactant depletion is achieved at a higher arterial PCO2 during ventilation with liquid than with gas.

Background: Inhibition 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.

Objective: To 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.

Pulmonary stretch receptor activity during Partial Liquid Ventilation in Cats with Healthy Lungs.

Aim: To study whether pulmonary stretch receptor (PSR) activity in mechanically ventilated young cats with healthy lungs during partial liquid ventilation (PLV) is different from that during gas ventilation (GV).

Methods: In 10 young cats (4.4 +/- 0.

Inhaled nitric oxide therapy in neonates and children: reaching a European consensus.

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.

Hyaluronan in the human neonatal lung: association with gestational age and other perinatal factors.

The aim of this study was to determine the influence of gestational age at birth, postnatal age, specific complications and methods of treatment on the lung hyaluronan concentration in infants. Lung samples and clinical records from 117 infants who died 0-228 days (32 weeks) after preterm or term birth were studied. The lung hyaluronan concentration at death was most strongly associated with the gestational age at birth, an association best described by an exponential function with a negative power coefficient.

Transepidermal water loss in developing rats: role of aquaporins in the immature skin.

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.

Lung hyaluronan during development: a quantitative and morphological study.

Hyaluronan, an important constituent of developmental interstitium in fetal lungs, mediates cell-to-cell interactions and thereby directs migrating cells. Furthermore, because of the polyionic nature of the molecule, hyaluronan forms open, hydrated matrices that provide channels for migrating cells. This hydrated matrix undergoes contraction before birth.