Pulmonary function tests as a predictor of chronic lung disease in ventilated preterm infants

BACKGROUND: The objective of this study was to determine if the value of respiratory system compliance and lung resistance could be a good predictor of chronic lung disease (CLD) in an early stage of this disease. METHODS: The study was carried out on 48 preterms infant (BW < 1500 g) who were ventilated for respiratory distress, calculating pulmonary mechanics at 3, 5, 7 and 10 days of life with a standardized protocol of measurements. RESULTS: Infants who did not develop CLD showed higher values of respiratory system dynamic compliance (Crsdyn) than the CLD group since the 5th day of life (p < 0.001). The values of lung resistance show a statistical significant difference between groups since the 7th day of life. CONCLUSIONS: These findings indicate that, with a well standardized method of measurements, the value of Crsdyn can well be a good predictor and a sensible prognostic factors for CLD.     

Molecular aspects of preterm labor

Preterm birth is a major problem in clinical obstetrics, occurring in approximately 10% of all pregnancies, and leading to 75% of early neonatal mortality and morbidity. Studies in our laboratory have examined the neuroendocrine mechanisms by which the fetus, through activation of the hypothalamic-pituitary adrenal axis, provides the stimulus to the onset of parturition. Maturation of this axis occurs prematurely in response to stimuli such as stress. Stress induced activation of HPA function in human pregnancy, may lead to increased output of corticotropin-releasing hormone (CRH) from placenta and fetal membranes. CRH is one of the agonists that acts in concert with increased prostaglandin biosynthesis to provide the stimulus to myometrial contractility in late gestation. Recent studies have also recognized that approximately 15% of patients in idiopathic preterm labor present, with deficiency of the major prostaglandin metabolizing enzyme in the fetal membranes, particularly chorionic trophoblast. Understanding these processes may lead to new methods of managing the patient presenting in preterm labor.     

In vitro effect of indomethacin on polymorphonuclear leukocyte function in preterm infants

During 1984 to 1988, the U.S. Occupational Safety and Health Administration (OSHA) investigated 10 incidents, with 11 fatalities, involving the inadvertent connection of air-line respirators to inert gas supplies. Seven deaths resulted from connecting an air-line respirator supply hose to a line which normally carried inert gas. Four deaths were caused by leakage or backfill of inert gas into a line which normally carried breathable air. Ten of the deaths were from nitrogen and one from argon. The circumstances of the 11 deaths indicated that coupling compatibility and supervisory oversight were major factors in the inappropriate supply of irrespirable gas to the respirators worn by these workers. Conscientiousness among safety personnel to the hazards of asphyxiation by inert gas, and compliance with current OSHA regulations, the ANSI Z88.2 standard, and NIOSH respirator certification approval regulations would have prevented these fatalities.     

Neonatal consequences of preterm PROM

Preterm premature rupture of the fetal membranes is associated with 30-40% of premature births and is an important cause of perinatal morbidity and mortality. Although the major causes of neonatal death associated with PPROM include prematurity complications, infection, and pulmonary hypoplasia, rupture in a preterm gestation also is associated with an increase in morbidity, including cerebral palsy, other developmental delays, as well as chronic lung disease. When PPROM occurs, antibiotic prophylaxis has been shown to reduce the potential for complications and should be considered. Neonates treated intrapartum with antibiotics should have fewer complications, a longer latency period, and an improved long-term outlook compared with those without antepartum or intrapartum prophylaxis.     

The preterm labor experience: a balancing act

The purpose of the study was to identify how women described, interpreted, and managed their preterm labor experience. Ten married, middle-class women participated in an in-depth, tape-recorded interview in the hospital after preterm labor was stabilized; periodically over the telephone after discharge from the hospital; and in the hospital, home, or via telephone after birth, for a total of 31 interviews. Using qualitative data analysis techniques, the findings were conceptualized as five recursive stages: becoming aware that something was wrong and feeling unbalanced, making sense of the experience as they sought to understand why preterm labor occurred, trying different strategies to re-create a balance in their lives, addressing other life stressors that threatened restoring balance, and emerging from the preterm labor experience with added growth. An increased understanding of the preterm labor experience from the women's perspective can be helpful to health care professionals and others who support women during pregnancy.     

Erythropoietin in very preterm infants

Three neonates (a male and two females of gestational ages 27, 27 and 29 weeks with birthweight 985, 660 and 1130 g), born to parents who are Jehovah's Witnesses, were admitted to our neonatal intensive care unit over a 2 month period in 1992. Human recombinant erythropoietin (rHuEpo, 200 u/kg sc. on alternate days for 6-8 weeks) was started early in conjunction with strict control of blood sampling in an attempt to avoid the need for blood transfusion. The lowest haemoglobin recorded was 95 g/L at 35 days of age in the first infant. The amount of blood withdrawn for sampling was 21.4 mL, 20.7 mL and 5.5 mL, respectively. All were discharged near their expected birthdate, never having received a blood transfusion in the Nursery. It is possible to manage sick, very preterm, very low birthweight neonates in a neonatal intensive care setting without the use of blood transfusions by the early use of rHuEpo in conjunction with strict control of blood sampling.     

Bone mineralization in preterm infants

In preterm neonates a large skeletal mineral deficit builds up between birth and 40 wk postconception. During the phase of catch-up growth between 40 and 60 wk postconception there is a catch-up in peripheral skeletal mineralization, so that by the age of 1 y the skeletal mineral content is similar in preterm and term infants, despite the former being smaller, a finding that has been replicated for lumbar spinal mineralization. Later follow-up studies suggest that this catch-up persists and mineralization remains appropriate for body size. However, given the continuing abnormal growth experience of former preterm individuals, it would still be important to examine their bone mineralization in early adulthood. A number of interventions can improve perinatal bone mineralization, but few studies examine their long-term effectiveness. One such study has suggested that a relatively poor mineral diet in this period is, counterintuitively, associated with a later advantage in skeletal mineralization. If this finding is repeatable, then it could result in a major change in nutrition strategy in the neonatal period.     

Aeromedical transfer of preterm labor patients

Obstetric patients are transported by air quite frequently. We evaluated transport times, obstetric outcomes, air-versus-ground transport costs, and related data on 22 helicopter aeromedical transports of pregnant patients with preterm labor. We found no significant differences between patients who delivered and those who did not when comparing transport time (167.1 +/- 41.9 minutes versus 177.1 +/- 56.2 minutes), air distance of transport (122.9 +/- 44.8 miles versus 143.6 +/- 23.8 miles), and other outcome measures. No deliveries occurred in flight. Air transport costs were significantly greater than estimated ground transfer ($4613.64 +/- $581.12 versus $604.02 +/- $306.38; P < .01). Two-way air transfer of preterm labor patients over moderate distances is more costly than contracted ground transfer costs at our institution.     

Development of attention in preterm infants

The quality of the awake state and attention in preterm infants has been evaluated by rating indices of attention such as widening of the eye, type of fixation, brightening, scanning, and cessation of sucking measured during visual fixation of patterns. Twenty-six infants ranging from 28 to 32 weeks' gestation at birth (mean, 31 weeks) were tested from one to four weeks postnatally until 36 weeks' gestation. Indices of attention were rated on a scale of 4 with an optimal mean index of 4. A progressive increase in behaviors associated with fixation of visual stimuli has been shown from 32 to 36 weeks of conceptual age. Mean scores ranged from 0.7 at 31 weeks' gestation to 1.8 at 34 weeks' and 2.7 at 36 weeks' gestation. The possibility therefore exists that by as early as 31 to 32 weeks from conception the human brain may be capable of waking states and thus able to process some sensory stimulation.rease in behaviors associated with fixation of visual stimuli has been shown from 32 to 36 weeks of conceptual age. Mean scores ranged from 0.7 at 31 weeks' gestation to 1.8 at 34 weeks' and 2.7 at 36 weeks' gestation. The possibility therefore exists that by as early as 31 to 32 weeks from conception the human brain may be capable of waking states and thus able to process some sensory stimulation.     

Splenic macrophages in preterm infants: a necropsy study

AIMS: To study the frequency and nature of histiocytes in the splenic red pulp of infants who died following complicated immaturity/prematurity. METHODS: Twenty four preterm/immature infants were investigated. Frozen sections of formalin fixed splenic tissue were stained with Oil Red O. Paraffin wax sections from the same tissue were conventionally stained with haematoxylin and eosin. Immunohistochemistry was carried out for a number of macrophage markers. The administration of Intralipid was compared with the presence and extent of tissue macrophages. RESULTS: The spleens of 10 infants showed varying degrees of Oil Red O positivity ranging from mild to strong. In all these cases varying numbers of macrophages were confirmed in the splenic parenchyma in ordinary sections. The immunomarkers indicated that the histiocytes belonged to the macrophage phagocytic system. Of the 10 cases with splenic macrophages all had received Intralipid. Of those not receiving Intralipid none showed splenic macrophages. Seven had received Intralipid but did not have splenic macrophages; they had either only received small amounts of Intralipid or Intralipid was discontinued before death. CONCLUSIONS: Splenic macrophages are common at necropsy in immature/preterm infants. The macrophages are most lucidly demonstrated using Oil Red O staining in frozen sections. There is a strong association between the presence of splenic macrophages and Intralipid administration.     

Hepatitis B vaccination in preterm infants

AIM: To investigate the immunogenicity and safety of existing recommendations for hepatitis B vaccination in preterm infants. METHODS: Recombinant hepatitis B vaccine (H-B-VAX II, 5 micrograms per dose) was given to 85 preterm infants divided into two groups, using two different schedules. Forty four group A infants with birthweights of < 2000 g received three doses at 1, 2, and 7 months of age. Forty one group B infants with birthweights of > or = 2000 g received three doses at 0, 1, and 6 months of age. RESULTS: After vaccination, 42 infants from group A (95%) and 37 infants from group B (90%) developed protective levels of antibody. The final seropositive rate and the geometric mean concentration of hepatitis B surface antibody between the two groups were not significantly different. The immune response of preterm infants to hepatitis B vaccines was similar to that of term infants in a previous study. CONCLUSIONS: Preterm infants can be given hepatitis B vaccines using one of the above two different schedules, at a cutoff birthweight of 2000 g.     

Word length and lexical activation: Longer is better.

Many models of spoken word recognition posit the existence of lexical and sublexical representations, with excitatory and inhibitory mechanisms used to affect the activation levels of such representations. Bottom-up evidence provides excitatory input, and inhibition from phonetically similar representations leads to lexical competition. In such a system, long words should produce stronger lexical activation than short words, for 2 reasons: Long words provide more bottom-up evidence than short words, and short words are subject to greater inhibition due to the existence of more similar words. Four experiments provide evidence for this view. In addition, reaction-time-based partitioning of the data shows that long words generate greater activation that is available both earlier and for a longer time than is the case for short words. As a result, lexical influences on phoneme identification are extremely robust for long words but are quite fragile and condition-dependent for short words. Models of word recognition must consider words of all lengths to capture the true dynamics of lexical activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)