An Analysis of a Rebreathing Method for Measuring Lung Volume in the Premature Infant

Ronchetti, R; Stocks, Janet; Keith, Ian; Godfrey, Simon

doi:10.1203/00006450-197510000-00011

Cited by 30 publications

(7 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Heaf et al (25) Differences in mode of ventilation may have contributed to these discrepancies (23,26). We can consequently confirm the observations that infants with IRDS and a demand for respiratory support have lower FRC than comparable groups without lung disease (27)(28)(29)(30). As shown in Figure 2, there was no correlation between PEEP level and FRC.…”

Section: Discussionsupporting

confidence: 75%

Lung Volume, Gas Mixing, and Mechanics of Breathing in Mechanically Ventilated Very Low Birth Weight Infants with Idiopathic Respiratory Distress Syndrome

et al. 1991

View full text Add to dashboard Cite

ABSTRACT. We assessed pulmonary function in 14 mechanically ventilated newborn very low birth weight infants with idiopathic respiratory distress syndrome by means of a face-out, volume displacement body plethysmograph and nitrogen washout analyses. Specially designed computer programs were used for calculations of lung volumes, ventilation, gas mixing efficiency, and mechanical parameters. In addition to very low compliance and moderately elevated resistance of the respiratory system, there were considerably impaired gas mixing efficiency and low functional residual capacity (FRC) For methodologic reasons, lung function studies in newborn infants with IRDS have largely been focused on lung mechanics. Using applied methods makes it possible to obtain a more comprehensive picture of ventilatory conditions, even in very premature, severely affected infants. To further clarify the pathophysiology of IRDS under conditions of mechanical ventilation in this group of infants, we assessed lung volume, alveolar ventilation, gas mixing efficiency, and lung mechanics in mechanically ventilated infants with birth weights below 1500 g. MATERIALS AND METHODSWe studied 14 very low birth weight infants with IRDS during intermittent positive pressure ventilation within 5 d (range 0-5 d) of birth. Six of the infants were boys and eight were girls. Median birth weight was 1.29 kg (range 1.00-1.50 kg) and median gestational age was 29 wk (range 26-33 wk). Informed consent was obtained from the parents of each infant before the procedure was camed out, and the study was approved by the ethics committee of Goteborg University.Maternal history included preeclampsia in six cases and abruption of the placenta in three cases. One infant was a twin. Twelve infants were delivered by cesarean section. Apgar scores were below 5 at 1 min in seven infants and below 7 at 5 min in seven infants. All infants were flushed with oxygen immediately after birth, and nine were also ventilated using a mask. Ten of the infants with adequate spontaneous respiration were treated with continuous positive airway pressure by nasal prongs within 4 h of birth, and the other four were intubated and ventilated within a few minutes of birth. Mechanical ventilation was started within 27 h in all infants. The pulmonary disease was classified as IRDS in all infants (1). All initial radiographs showed a reticulogranular pattern, and no infant had positive blood cultures or hematologic signs of infection.The following guidelines for mechanical ventilation of very low birth weight infants with IRDS were used in the intensive care unit: Nasal intubation with uncuffed endotracheal tubes 2.5-3.0 (Portex LTD, Hythe, Kent, UK) was performed. A Sechrist Infant Ventilator 400 B (Sechrist Industries Inc., Anaheim, CA) was connected to the endotracheal tube. The breathing gas was humidified and heated with a humidifier (Fisher and Paykel, Auckland, New Zealand). Initial ventilator settings were: respiratory rate 60 breathslmin, inspiratory/expiratory ratio 112, PIP 25-30 cm H20,...

show abstract

Section: Discussionsupporting

confidence: 75%

Lung Volume, Gas Mixing, and Mechanics of Breathing in Mechanically Ventilated Very Low Birth Weight Infants with Idiopathic Respiratory Distress Syndrome

et al. 1991

View full text Add to dashboard Cite

show abstract

“…FRC in our preterm infants was 22.5 ± 2.1 ml/kg, which is in the range of previous studies in spontaneously breathing preterm infants using gas dilution techniques. 7,23,24 The correlation between weight and FRC was strong. No significant gender difference in mean FRC was found.…”

Section: Discussionmentioning

confidence: 92%

Moment analysis of multibreath nitrogen washout in healthy preterm infants

et al. 1998

View full text Add to dashboard Cite

Moment analysis (MA) of multibreath nitrogen washout (MBNW) has not previously been applied to newborn infants. The aim of the present study was to adapt this method to healthy preterm infants using an improved technique suitable for small infants, and to determine reference values of MA. Twenty healthy preterm infants with a mean birth weight (± SD) of 1,666 ± 402 g and a mean gestational age of 31.3 ± 2.1 weeks were studied during their first 7–28 days of life. Computerized bedside equipment with very low dead space was constructed. The limits of normal variability were determined from results of duplicate studies. Outcome variables included functional residual capacity (FRC), the first‐to‐zeroth moment ratio (M1/M0), the second‐to‐zeroth moment ratio (M2/M0), and the lung clearance index (LCI). The starting point for MA had considerable impact on the results. Mean M1/M0 and M2/M0 were 2.18 ± 0.18 and 8.71 ± 1.24, respectively. No significant relation between moment ratios and weight, gender or age was found. Intrasubject coefficients of variation (CV) for M1/M0 (7.9 ± 5.9%) and for M2/M0 (12.1 ± 9.1%) and intersubject CV for M1/M0 (8%) and M2/M0 (14%) were similar to those reported in children and adults. Mean lung clearance index was 10.8 ± 1.4 and intra‐ and intersubject CVs were 11.3 ± 8.9% and 13%, respectively. Mean functional residual capacity (FRC) was 22.5 ± 2.1 ml/kg. Mean intra‐ and intersubject CVs for FRC were 8.3% and 9%, respectively. We conclude that the MBNW test can be performed by a simple bedside method and that MA appears to be a suitable method for measuring gas mixing in preterm infants. Pediatr. Pulmonol. 1998; 25:52–58. © 1998 Wiley‐Liss, Inc.

show abstract

“…in our volume measurements the mean helium dilution time was 110 s, with nondilution time less than 60 s. This insured that the equilibrium had in fact been reached in these normal premature newborns [15,20,21], as confirmed by the FHe record ings showing a plateau level for more than 30 s [15], Our mean values and ranges for FRC were in agreement with those pre viously published [13-15, 20, 22-24], Our study however avoided using oxygen-en riched mixtures which lower FRC, as com pared to values obtained with the use of 21 % oxygen (15], Thus, a valid comparison of our results can only be made with the data from Geubelle et al [14,15] and Berglund and Karlberg [13], who published FRC values measured when the baby is breathing a gas mixture with 0.21 FICH and using the same method as used here. Our mean FRC in QS (1.36 ml/cm) was somewhat lower than that of Geubelle (1.5 ml/cm), but the ranges were almost the same in both studies.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, trapped gas [ 15,20,24] may explain the higher values for TGV than for FRC. The mean TGV in AS [1], which is very similar to our mean FRC in AS.…”

Section: Discussionmentioning

confidence: 99%

Functional Residual Capacity and Sleep States in the Premature Newborn

et al. 1983

View full text Add to dashboard Cite

Functional residual capacity (FRC) variations in relation to sleep state changes were studied in 11 premature infants with birth weights of 1.68 ± 0.48 kg and gestational ages of 32.7 ± 2.2 weeks (mean ± SD). Helium dilution was used to measure FRC, and sleep states were identified using neurophysiologic criteria. No significant difference in FRC could be demonstrated between data collected during active sleep (AS) and quiet sleep. However a relationship was shown between AS and paradoxical breathing (p < 0.02) and between AS and irregular breathing (p < 0.05). Several factors are discussed which might explain the discrepancy between the present data in premature infants and the previously published data in term infants. (1) Neurophysiologic identification of sleep states does not include breathing pattern whereas behavioral identification does. It is therefore possible that lung volume changes are related to breathing pattern changes and not to sleep state changes per se. (2) Maturational changes may occur among the mechanisms which control FRC, leading to a progressive stabilisation of FRC, the variation of which could become related to sleep state changes.

show abstract

An Analysis of a Rebreathing Method for Measuring Lung Volume in the Premature Infant

Cited by 30 publications

References 8 publications

Lung Volume, Gas Mixing, and Mechanics of Breathing in Mechanically Ventilated Very Low Birth Weight Infants with Idiopathic Respiratory Distress Syndrome

Lung Volume, Gas Mixing, and Mechanics of Breathing in Mechanically Ventilated Very Low Birth Weight Infants with Idiopathic Respiratory Distress Syndrome

Moment analysis of multibreath nitrogen washout in healthy preterm infants

Functional Residual Capacity and Sleep States in the Premature Newborn

Contact Info

Product

Resources

About