Respiratory water loss in relation to activity in fullterm infants on their first day after birth

Respiratory water loss (RWL), oxygen consumption and carbon dioxide production were measured in ten fullterm infants on their first day after birth, using an open flow-through system with a mass spectrometer, specially equipped with a water channel, for analysis of gas concentrations. Measurements were made both with the infant asleep and during different levels of motor activity. The ambient temperature was maintained at approximately 32.5 degrees C and the ambient relative humidity at 50%. RWL increased from 4.2 +/- 0.7 (SD) mg/kg min when the infant was asleep to 6.3 +/- 1.0 mg/kg min when he or she was awake but calm; with increasing activity there was a further increase in RWL. The oxygen consumption increased from 5.4 +/- 0.9 (SD) ml/kg min during sleep to 6.9 +/- 0.8 (SD) ml/kg min when awake, and also increased further with increasing activity.     

Respiratory water loss in relation to gestational age in infants on their first day after birth

Respiratory water loss, oxygen consumption and carbon dioxide production were measured in 32 infants on their first day after birth. Gestational age was between 27 and 41 weeks. All infants were studied in incubators with 50% ambient relative humidity and an ambient temperature that allowed the infant to maintain a normal and stable body temperature. During the measurements the infants were usually asleep. Respiratory water loss was found to be highest in the most preterm infants and lower in more mature infants. Respiratory water loss per breath (mg/kg) was almost the same at all gestational ages and the higher respiratory water loss found in the most preterm as compared with the more mature infants is thus due to a higher rate of breathing. Oxygen consumption was lowest in the most preterm infants and increased with increasing gestational age. Thus, in full-term infants respiratory water loss and transepidermal water loss are of approximately equal magnitude at an ambient humidity of 50%, while respiratory water loss constitutes a smaller proportion than trans-epidermal water loss in very preterm infants. Respiratory water loss increases with the rate of breathing. ? Insensible water loss, oxygen consumption, preterm infants, respiratory water loss G Sedin, Department of Paediatrics, University Hospital, S-751 85 Uppsala, Sweden     

The effect of a warm environment on respiratory water loss in fullterm newborn infants on their first day after birth

Continuous measurements of respiratory water loss (RWL), oxygen consumption and carbon dioxide production were made in 21 fullterm infants on their first day after birth. The infants were first studied in incubators with a temperature of 32.5 degrees C and an ambient humidity of 50%. After an interval with stable conditions the incubator temperature was raised to 36.5 degrees C while the water vapour pressure was kept constant. When the rectal temperature had increased to 37.8 degrees C or when the infant had started to sweat, the relative humidity in the incubator was increased to 50%. At the start of the measurements mean RWL was 4.9 mg/kg min. On the average, RWL increased to a maximal value of 7.0 mg/kg min in the warm environment. Mean oxygen consumption only increased from 5.3 to 5.8 ml/kg min. This meant that when nursed in this warm environment the infants were able to increase their respiratory water loss by nearly 50% without a significant change in oxygen consumption.     

Respiratory water loss and oxygen consumption in full-term infants exposed to cold air on the first day after birth

Respiratory water loss, oxygen consumption, carbon dioxide production and skin blood flow were measured continuously in nine full-term infants on the first day after birth. After at least 18 min of measurements with the infant asleep in an incubator, with an air temperature of 33°C and a relative humidity of 50%, the temperature of the incubator air was lowered to less than 27.5°C. This resulted in a significant decrease in skin temperature and peripheral skin blood flow, while the infant's core temperature remained unchanged. At the same time, mean respiratory water loss increased from 3.7 to 6.1 mg/kg-min, which can be explained partially by the decrease in ambient humidity that accompanied the decrease in air temperature. In addition, mean oxygen consumption increased from 5.3 to 7.9 ml/kg. min and mean carbon dioxide production increased from 3.8 to 5.9 ml/kg-min. There was no concomitant increase in motor activity. Thus, when the newborn infants were exposed to cool air, they reacted with an increase in respiratory water loss, oxygen consumption and carbon dioxide production before their core temperature was affected and without increasing their motor activity.     

Indomethacin therapy on the first day of life in infants with very low birth weight

To investigate the optimal timing for treatment of small premature infants, we performed a double-blind, controlled trial of indomethacin therapy on the first day of life in 104 infants weighing between 700 and 1300 gm. Infants were given indomethacin or placebo at a mean age of 15 hours. Eleven of the 56 infants given placebo developed large left-to-right shunts through a patent ductus arteriosus. In contrast, only two of the 51 infants given indomethacin developed large shunts (P less than 0.025). There were no significant differences in incidence of surgical ligation, duration of oxygen therapy, duration of endotracheal intubation, days required to regain birth weight, or incidence of complications. However, the power of the tests of significance was low because of the small number of patients. Thus, although the incidence of large left-to-right ductus shunts was decreased in the indomethacin group, morbidity was not otherwise altered for the entire group of patients, possibly because of the relatively low incidence (21%) of large shunts in the placebo group. We conclude that although treatment with indomethacin on the first day of life appears to be safe, there is little advantage to its use in centers where the incidence of large shunts through a patent ductus arteriosus is relatively low.     

Respiratory water loss and oxygen consumption in newborn infants during phototherapy

Respiratory water loss was measured together with oxygen consumption (VO2) and carbon dioxide production (VCO2) in 11 full-term and eight preterm infants (mean gestational age 34 weeks, range 31-36 weeks) before and during 1 h of phototherapy. The method for determination of respiratory water loss, VO2 and VCO2 was based on an open flow-through system with a mass spectrometer for measurement of gas concentrations. All infants were studied naked in an incubator with an ambient relative humidity of 50% and with a controlled environment with respect to temperature and air velocity. The infants were calm during the measurements. Before phototherapy, in term infants respiratory water loss was 4.4 (SD 0.7) mg/kg min and VO2 5.9 (0.9) ml/kg min and in preterm infants respiratory water loss was 4.7 (0.8) mg/kg min and VO2 6.1 (0.8) ml/kg min. No significant difference was found between values obtained during or after 1 h of phototherapy and those obtained before.     

极低出生体重儿的呼吸管理

出生前胎儿肺组织的发育可分为4个时期：①假腺期：胎儿5～17周,因此期的肺组织切片与腺体相似而得名。此期支气管分支已形成,通气系统逐渐建立,但气体交换部分尚未建立,故无气体交换功能。②小管期：胚胎17～25周,肺组织、毛细血管和肺的呼吸部分生长为本期的特点。此期支气管树进一步发育完善,肺组织也有了丰富的血液供应,肺的呼吸部分快速发育,肺组织分叶形态逐渐消失,上皮细胞较间质增殖迅速,腺泡上皮已演变为扁平上皮,Ⅱ型上皮细胞已形成,间质中毛细血管逐渐增多,形成原始的气体交换单位,此期已基本具备了呼吸功能。③原始肺泡期：指胎儿24周至新生儿阶段,又称终末囊泡期。此期原始肺泡数目较少,肺泡囊逐渐成熟,间质组织减少,毛细血管增生,肺泡气体交换能力及表面活性物质仍不足,至第34～35周才迅速上升。④肺泡发育期：指胎儿后期到生后8岁。肺泡的发育主要在生后肺泡体积增加,主要由原始肺泡数日增加和每个原始肺泡体积的增大,足月时为小而浅的原始肺泡,直径约150μm,至8岁时肺泡直径约300μm,数量较出生时增加12．5倍。     

Changes in red cell phosphate metabolism of preterm and fullterm infants with perinatal problems during their first month of life

The effects of perinatal problems on red cell phosphate metabolism were studied in two groups of infants (preterms B and fullterms D) during the first month of life. All infants started milk feeding from day three after birth. The results were compared to those of healthy preterms (A) and fullterms (C), respectively. Comparisons were also made between the preterm and fullterm groups B and D. The preterms with perinatal problems (B) showed a significant delay in catching up with the plasma and red cell inorganic phosphate (Pi) levels of controls (A) throughout the first month of life (p < 0.05). In parallel, the erythrocyte 2,3 diphosphoglycerate (2,3-DPG) concentrations of the sick preterms lagged significantly behind those of controls (p < 0.001); but the ATP levels were comparable between the two groups. The fullterms behaved slightly differently. No significant differences in plasma Pi (Pl Pi) and red cell 2,3-DPG were seen between the sick and healthy neonates during the month of study, while red cell Pi (RBC Pi) and ATP were found to be lower in the sick ones (p < 0.05). The fullterms with perinatal problems (D) had significantly higher Pl Pi (p < 0.05) and RBC Pi (p < 0.01) than preterms with problems (B) from the first week of life and continued in a similar pattern until the end of the month. Red cell 2,3-DPG concentrations were found to be significantly correlated with Pl Pi and RBC Pi in both preterm groups (p < 0.01) and in the sick fullterms (p < 0.001) during the time of the study. In the healthy fullterms 2,3-DPG was found to correlate only with red cell Pi (p < 0.05). Perinatal problems seem to affect Pi metabolism to a different degree in preterm and fullterm neonates in the first month of life.     

Respiratory strategies for preterm infants at birth

Neonatologists treating extremely premature infants in the delivery room are faced with many dilemmas, not least how best to support their breathing. A balance must be struck between helping those infants who need it and not applying potentially harmful treatments to infants who might not need them. Crucial to this process is being able to identify infants who might benefit.     

Transepidermal water loss in newborn infants. IX. The relationship between skin blood flow and evaporation rate in fullterm infants nursed in a warm environment

In order to investigate whether a change in skin blood flow is associated with changes in the evaporative loss of water from the skin of fullterm appropriate for gestational age infants, we measured the evaporation rate and skin blood flow in the body temperature range 36.6 to 37.2 degrees C. Fifteen healthy, fullterm newborn infants delivered by Caesarean section were studied in a warm environment. Evaporation rate and skin blood flow were measured non-invasively without disturbing the infant. When the body temperature slowly rose because of the warm environment, the skin blood flow steadily increased. The rate of evaporation of water from the skin slowly decreased until a body temperature of 37.1 degrees C was reached. The evaporation rate then suddenly increased as the infant began to sweat. Thus, in fullterm newborn infants born by Caesarean section the skin blood flow increases in the body temperature range 36.6-37.1 degrees C but does not influence the evaporation rate from the skin.     

Quantitative electroencephalographic patterns in normal preterm infants over the first week after birth

Background

Currently available tools to assist clinicians with prediction of neurodevelopmental outcome of preterm infants are inadequate. Modified cotside electroencephalography (EEG) has the ability to produce quantitative electrophysiologic measures. These measures may be useful in future prediction of outcome.

Aim

To determine patterns of change in quantitative EEG measures in preterm infants during their first week after birth.

Design

Observational.

Subjects

Preterm infants born at less than 32 weeks completed gestation surviving to discharge with unremarkable serial ultrasound scans.

Outcome measures

Changes in continuity, amplitude and spectral edge frequency measures of EEGs obtained over the first week after birth.

Results

Results of EEGs performed using a novel EEG device on 63 infants are reported here. Their median (range) gestation was 29 (24-31) weeks and birthweight was 1235 (540-1980) g. Quantitative measures of EEG continuity increased over the first week after birth from 72 (25-99)% to 92 (54-100)% at the 25 μV threshold, and from 39 (10-87)% to 64 (34-75)% at the 50 μV threshold, both p < 0.0001. There was a related 32% increase in median amplitude from 5.8 (2.6-10.6) μV on day 1 to 7.6 (4.3-9.4) μV on day 4, p = 0.005. There was a trend for average spectral edge frequency to fall from 10.7 (9.3-12.9) Hz on day 1 to 9.9 (8.1-12.3) Hz on day 3, p = 0.06. Each gestational tertile showed similar patterns.

Conclusions

There are consistent changes in quantitative neurophysiologic measures over the first week after birth, and particularly measures of continuity over the first 4 days, in normal preterm infants.     

General movements in healthy full term infants during the first week after birth

Background

The quality of general movements (GMs) is a widely used criterion to assess neurological dysfunction in young infants. It is unknown, however, whether the birth process influences the motor repertoire of healthy full term infants during the first week after birth.

Aims

To assess the quality of GMs and to determine the motor optimality score (OS) in healthy full term infants during the first week after birth and to evaluate the influence of the mode of delivery on GM quality.

Study design

Thirty-three healthy full term infants born either vaginally or after caesarean section (CS) under spinal anaesthesia were video recorded in the first week after birth in order to assess GM quality and to determine OS with Prechtl's method.

Results

Abnormal GMs were observed mainly on the early recordings: 86% on the day of birth (day 0), 94% on day 1, and 68% on day 2. On days 5 to 7 (day 5–7) all GMs were normal (P < .001). The OSs increased significantly from median 12 on day 0 to 18 on day 5–7 (P < .001). Monotonously slow movements were frequently seen during the first days but not on day 5–7 (P < .001). GM quality and OS did not differ between infants born by vaginal delivery or after CS under spinal anaesthesia.

Conclusions

Healthy full term infants often showed abnormal GM quality and lower OSs during the first week after birth, irrespective of the mode of delivery. GM quality normalised during subsequent days and was normal on day 5–7.     

Nutrient intake by breast-fed infants during the first five days after birth

The intakes of milk and specific nutrients during the first 120 hours after birth were measured in 11 full-term, breast-fed infants. Infants were test weighed at all feeds using an electronic balance, and milk samples were obtained from both breasts one to three times daily. Milk was analyzed for levels of fat, protein, lactose, calcium, sodium, and potassium; energy content was calculated using the Atwater factors. The average (+/- SD) intake of milk in the first 24 hours after birth was 13 +/- 16 g/kg (range, 3 to 32 g/kg), increasing to 98 +/- 47 g/kg (50 to 163 g/kg) and 155 +/- 29 g/kg (110 to 196 g/kg) on days 3 and 5, respectively. Mean daily intakes of energy, lactose, calcium, and potassium were less than 12% of the mean day 5 intake on day 1 and less than 25% of the day 5 intake on day 2. In the first few days after birth, the nutrient intake of the solely breast-fed infant is highly variable and is frequently low.     

Respiratory inhibition after crying in infants

BACKGROUND: Among full-term neonates, the authors discovered infants who showed respiratory inhibition after crying which involved a marked decrease in SpO2. The infants were found to present increased echogenicity or a cyst in a cranial region termed the ganglionic eminence, or to have a subependymal cyst. The authors prospectively examined the relationship between respiratory inhibition after crying and these changes to examine the prevention and treatment of the episode. METHODS: The authors conducted cranial ultrasonography to screen 381 full-term neonates who showed no abnormalities at birth and whose parents requested ultrasonographic screening of the head, followed by polygraphy of infants who showed increased echogenicity or a cyst in ganglionic eminence, or had a subependymal cyst. The authors similarly conducted polygraphy for 50 neonates without cranial ultrasound abnormalities; the former constituted the control group. Respiratory inhibition was defined to be central apnea immediately after crying with a decrease in SpO2 to <60%. RESULTS: Among 381 neonates examined, 104 showed cranial ultrasound abnormalities; 60 of the 104 neonates indicated respiratory inhibition after crying. Oxygenation failed to improve the episode in 17 neonates with severe respiratory inhibition. However, theophylline alleviated the episode, and SpO2 no longer decreased to <60%. Theophylline was discontinued successfully by 6 months after birth, while 50 neonates in the control group showed no respiratory inhibition after crying. CONCLUSION: Respiratory inhibition after crying which involved a marked decrease in SpO2 was observed in full-term neonates who showed no abnormalities after birth. These neonates could be screened by cranial ultrasonography.     

Language development of very low birth weight infants and fullterm controls at 12 months of age

Twenty-eight very low birth weight (VLBW) and 32 full term infants were prospectively assessed at one year of age for hearing, language development and neurological status. The prevalence of conductive hearing deficits was the same in both groups. Language scores in VLBW infants were significantly lower than in fullterm controls and 39% had significant language delays. VLBW infants exhibited a shorter attention span and were less likely to understand simple questions, to recognize objects or body parts when named, to initiate speech-gesture games, to follow simple commands and to imitate or use words consistently. Language quotients were directly associated with gestational age and five minute Apgar scores and inversely associated with severity of intraventricular hemorrhage, bronchopulmonary dysplasia and length of hospital stay. VLBW small for gestational age infants exhibited more advanced language skills than VLBW appropriate for gestational age infants. Language delays were more prevalent among, but not limited to, infants with mild to moderate neurological abnormalities. The influence of prematurity and VLBW on language development is complex and multifactorial and research is continuing to determine the predictive validity and long term significance of the early language delays described in this study.