Studies of Respiratory Physiology in the Newborn Infant. III. Measurements of Mechanics of Respiration1

Cook, Charles D.; Sutherland, James M.; Segal, Sydney; Cherry, Ruth B.; Mead, J.; McIlroy, Malcolm B.; Smith, Clement A.

doi:10.1172/jci103441

Cited by 245 publications

(16 citation statements)

References 12 publications

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“…At 2-35 minutes of life, pulmonary resistance averaged 35 + 20 cm H20/l/sec; the difference be tween this value and the value found later is, however, statistically not significant. The values obtained after 1-2 hours of life are in good agreement with those obtained at corresponding ages by using pneumotachygraph flow recording (Swyer et al, 1960: 26 cm H^O/l/sec, Polgar and String, 1966: 34 cm H^O/l/sec) or calculation of flow rate from volume recording by means of a body plethysmograph (Cook et al, 1957: 29 cm H20/l/sec.…”

Section: Further Development Of Pulmonary Mechanics and Lung Volumesupporting

confidence: 83%

“…The trend of changes in compliance occurring during the first day of life has been confirmed by Drorbaugh et al [1963] and Chu et al [1964]. On the other hand, respiratory work is significantly higher than the values reported by Cook et al [1957] and Swyer et al [I960]. This is apparently due to the signi ficantly bigger tidal volumes obtained with the »reverse» plethysmograph technique fol lowing rebreathing.…”

Section: Further Development Of Pulmonary Mechanics and Lung Volumementioning

confidence: 67%

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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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Section: Further Development Of Pulmonary Mechanics and Lung Volumesupporting

confidence: 83%

Section: Further Development Of Pulmonary Mechanics and Lung Volumementioning

confidence: 67%

Lung Function and Acid‐base Balance in the Newborn Infant

Koch¹

1968

Acta Paediatrica

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“…In the present study, values for resistance were also lower thah those obtained by COOK et al [5], 29 cm H,O/l/s (SE f 4) in 18 infants, or by SWYER et al [13], 26 cm H,O/l/s in 9 infants. These investigators used a plethysmograph and pressure-volume tracing to calculate resistance and employed a water-filled esophageal catheter connected to a pressure transducer [7] eliminates the nasal catheter and probably provides a better estimate of the true value for airway resistance, but it might underestimate the value somewhat if, in the presence of small airways, the respiratory rate was too rapid to permit pressure equilibration between mouth and alveoli during lung volume determinations.…”

Section: Discussioncontrasting

confidence: 65%

“…There is less information about these measurements, however, in infants and in subjects under four years of age. COOK et al [5] and SWYER et al [13] employed an esophageal catheter and total body plethysmograph to obtain pressure-volume curves and indirectly calculated resistance in newborn infants. POLGAR [I 1, 121 used a pneumotachometer, oscilloscope, and the total body plethysmograph method of D u~o r s et al [7] to measure airway resistance in the newborn; he used an esophageal catheter to measure compliance.…”

Section: Introductionmentioning

confidence: 99%

Airway Resistance and Lung Volume in the Newborn Infant

1969

Pediatr Res

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ExtractThe total body plethysmograph method of DuBo~s et al. [7] for measurement of lung volume and airway resistance was adapted to the study of newborn infants. A Rendell-Baker mask directly controlled by the operator proved by trial and error to minimize the chances of pressure leaks and undesirable pressure on the nose and allowed the mandible to be pulled forward to minimize pharyngeal obstruction. Use of an oscilloscope for direct visualization of flow and pressure tracings was essential in order to detect immediately pressure leaks, artifacts, and abnormal patterns during measurements of both lung volume and airway resistance.Interpretation of the measurements of airway resistance and of the relation of conductance to lung volume over a wide range of age and lung volumes requires that the flow rates at which measurements are made be recorded, along with lung volumes.I n 51 newborn infants, an airway resistance value of 19.2f 5.6 cm H,O/l/s was observed. Thoracic gas volume at functional residual capacity was 89.9+ 15.5 ml. The resulting mean value for conductance (reciprocal of airway resistance), 0.052 l/s/cm H,O, fell above the calculated regressions of conductance versus lung volume determined by BRISCOE and DuBo~s [3], who used data obtained from older children and adults. Direct conlparison is limited since airway resistance in the older subjects was usually obtained using panting flow rates of 0.5 l/s, while the infants in this study had flow rates of approximately 0.1 11s at the time airway resistance was measured. SpeculationConfirmation of the presence of the major expiratory flow-limiting segment in the nasal airway of newborn and small infants is needed. This location suggests a physiologic means for slowing expiratory flow and thus maintaining expiratory intraluminal pressure in the tracheobronchial tree, which might protect the compliant trachea and major bronchi from compression by positive intrapleural pressure in obstructive pulmonary disease. I t is possible that there is an airflow-lung volume-airway resistance relation throughout life; however, a wide range of control data will be required to establish such a relation.

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“…Using this system we were able to measure tidal Volume (VT), respiratory frequency (f), expiratory minute volume (VE) and, by simultaneous analysis of the pressure, volume and flow traces, the dynamic compliance (CD), and midvolume total pulmonary resistance (TPR,0) (Cooke et al, 1957 …”

Section: Methodsmentioning

confidence: 99%