Pulmonary Ventilation and Diffusion in the Human Newborn Infant1

Stahlman, Mildred T.

doi:10.1172/jci103503

Cited by 41 publications

(8 citation statements)

References 13 publications

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“…The mean value obtained in the present study is somewhat lower than those of others, and the coefficient of variation somewhat higher, although it compares favorably with that of Stahlman (15). These differences are more marked for smaller infants than larger infants in the present study, the larger infants falling just outside the lower limits of the others (10,15). Physiologic rather than methodologic differences account for this.…”

Section: Discussioncontrasting

confidence: 63%

Carbon Monoxide Diffusing Capacity in Newborn Infants

1976

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ExtractIn order to test the role of diffusing capacity in determining the arterial oxygen tension of newborn infants, pulmonary diffusing capacity for carbon monoxide (DL,,) was measured in 21 healthy infants ranging in birth weight from 765 to 4,720 g. DL,, in infants without respiratory distress correlated well with lung volume ( r = 0.76, P < 0.001). A smaller correlation (r = 0.39, P < 0.01) was obtained between DL,, and arterial oxygen tension. D L , per unit volume of lung is similar when healthy premature infants, full term infants, and normal adults are compared.The wide range of normal values obtained in resting infants and the lack of correlation with arterial oxygen tensions are similar to observations made in adults. SpeculationDiffusion "block" was not demonstrable in this study, even in infants with mild hypoxemia. These data, in conjunction with other studies reviewed in this report, suggest that lung volume plays a critical role in the level of arterial oxygen tension in newborn infants.

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Section: Discussioncontrasting

confidence: 63%

Carbon Monoxide Diffusing Capacity in Newborn Infants

1976

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“…The small size and the lack of cooperation of the subject to be studied make pulmonary function investigation in the newborn period difficult and limit its possibilities. The present series of studies as well as those of others [Cook et al, 1955;Stahlman, 1957;Nelson et al, 1962;Strang and McGrath, 1962;Prod'hom et al, 1964;and others), however, have demonstrated that suitable methods can be developed or adapted permitting inves tigation of the main mechanisms in respira tory function even in the youngest age group.…”

Section: Steady State Pulmonary Ventilation and Diffusing Capacity [Vi)supporting

confidence: 60%

Lung Function and Acid‐base Balance in the Newborn Infant

Koch¹

1968

Acta Paediatrica

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Summary During gestation the placenta subserves the external respiration of the fetus as well as its metabolism. With the initiation of extrauterine life the placental circulation is eliminated and the fetus emerges from a watery environment into air. This implies the establishment of a new autonomic function, that of pulmonary respiration, which process is intimately linked to a profound readjustment of the circulation. The present series of investigations has been performed to elucidate certain of the processes involved in pulmonary gas exchange and to evaluate its efficiency compared to adult standards during the period of adjustment to extrauterine life. Though the most important and rapid changes in this adaptative process occur during the first seconds and minutes of extrauterine life they continue far beyond this period. Observations have therefore been extended until the end of the neonatal period defined as the first week of life; this has been considered particularly important as information as to the later period of this adjustment is scarce or lacking. Emphasis is laid on development of function. Because of the significant morbidity and mortality of the newborn infant in disorders of respiration all investigations throwing more light on the normal respiratory mechanisms and their alterations in disease have important practical implications by improving diagnostic possibilities and facilitating objective evaluation of therapeutic measures. A total of 172 healthy fullterm infants born after an uneventful pregnancy of normal length and uncomplicated vertex delivery are the subjects of the different studies. The size of the subjects to be studied and the lack of cooperation posed special methodological problems. Suitable procedures and methods permitting reproducible and valid measurements have been developed or adapted for the study of mechanics of breathing, functional residual capacity, pulmonary ventilation, diffusing capacity and gas exchange. Since capillary PO2 does not accurately reflect arterial PO2 a safe procedure permitting arterial blood sampling without disturbing steady state conditions had to be developed. The onset of respiration and initial aeration of the lungs is characterized by the generation of very high resistive forces, probably mainly due to high surface tension. Subsequently, lung compliance increases while lung resistance and inspiratory work decrease, the speed of these changes being highest in the beginning and slowing down subsequently. Within one hour after delivery, the functional residual capacity amounts to 40—80 ml and shows a relation to lung compliance similar to that later in life. Changes after 24 hours of life are insignificant. There is hypoxemia, CO2 retention and accumulation of fixed acids, i. e. respiratory and metabolic acidosis at birth. The respiratory component of acidosis is on the average abolished at 30 minutes and metabolic acidosis at 24 hours of life. PCO2 attains a minimum of about 33 mm Hg at 24 hours of life and increases slightly to 36 mm Hg at 7...

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“…Our average value at 24-48 hr of age 1.52 f 0.09) falls within the ranges reported in human newborns at this age (6,9,12). These latter studies were all made using a steady state CO uptake technique (4).…”

Section: Discussionsupporting

confidence: 83%

Pulmonary Diffusing Capacity in Lambs during the Early Neonatal Period

et al. 1978

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Summarvwhen auiet they were intubated. Lambs in which re~eated studies were d a d e weie bottle fed. A rebreathing method was used to make 53 measurements Of DLco was measured by the rebreathing method (10) with slight pulmonary diffusing (D~CO) and capac-modifications for small animals, The volume of the rebreathing ity (FRC) in 17 newborn lambs during the first 2 days of life. D~eo, system was 400 and the lambs were ventilated from a 60-ml FRC, and DL~O/FRC all increased in studies made at 24-48 hr of syringe, The rebreathing circuit was made up of 3/16-inch ID age 'Ompared to those at 2-4 hr Of age: D~c o * 0'18 plastic tubing (Tygon tubing, Norton Plastics and Synthetics * Oeo9 ml/min/torr; FRC 37 * lo to 60 * m1 and DLcO/FRC Division, Akron, OH) which connected the endotracheal tube and 2.52 + 0.75 to 2.89 + 0.37 ml/min/torr/ml x D L~, measured ventilation syringe to a double headed pump (model no, using 0'005% C0 in the test gas was not different than that W21R031, Cole Palmer Instrument Company, Chicago, IL) where measured using 0.5% CO.the gas sample was split and run through a helium analyzer (Warren E. Collins Inc., Braintree, MA) and carbon monoxide Speculation analyzer (model no. 865 infrared analyzer, Beckman Instruments ~h~ increase in pulmonary diffusing capacity is in part due to Inc., Fullerton, CA) in parallel. The output of both analyzers was an increase in lung volume, but the significant increase in cOntinuOusl~ B44 P~~Y~~~P~, AssOciDLco/FRC demonstrates that other factors such as a change in ates In'., Beaverton, OR) at a paper 'peed of cm/sec. The pulmonary capillary blood volume may also be We entire rebreathing circuit was equilibrated with gas made up of conclude that there is no evidence for a co carrier in the early either 0.005 or 0.5% CO, 8.0% helium, 20.9% oxygen, and balance neonatal period in lambs. nitrogen (Airco Industrial Gases, Vancouver, WA). The circuit was then attached to the endotracheal tube at the end of expiration and the lamb rapidly rebreathed at 40-50 breaths/min with a tidal The is an index of the lung's capability for oxygen transport volume of 60 ml for 33-45 set. and is dependent upon alveolar volume and pulmonary capillary DLCO and FRC were calculated from the recorded changes in blood volume. Although DLco has been measured in human neo-CO and helium concentrations (Fig. 1) as follows nates (6, 9, 12), none of these studies have made a systematic = (0.693/t1/2) X Vs/BP -47 examination of the first 2 days of life. The early neonatal period involves the establishment of FRC (1,7,8) and the reabsorption where DLco = lung diffusing capacity in milliliters per min per of pulmonary fluid (2, 5, 1 I), which may in turn affect the volume torr STPD; t = time in minutes for [CO] to fall by 50%; Vs = of blood in the pulmonary capillary bed. We have measured DL~,, volume of the entire rebreathing system (rebreathing circuit plus and FRC by a rebreathing method in lambs in lambs at 2-4 hr of lung volume) in milliliters STPD; BP = barometric pressure in age and at 24-48...

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Pulmonary Ventilation and Diffusion in the Human Newborn Infant1

Cited by 41 publications

References 13 publications

Carbon Monoxide Diffusing Capacity in Newborn Infants

Carbon Monoxide Diffusing Capacity in Newborn Infants

Lung Function and Acid‐base Balance in the Newborn Infant

Pulmonary Diffusing Capacity in Lambs during the Early Neonatal Period

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