Neck and Body Position Effects on Pulmonary Mechanics in Infants

PEDIATRICS ◽  
1989 ◽  
Vol 84 (4) ◽  
pp. 670-674
Author(s):  
Waldemar A. Carlo ◽  
Aris Beoglos ◽  
Bonnie S. Siner ◽  
Richard J. Martin
Keyword(s):  
Bronchopulmonary Dysplasia ◽  
Body Position ◽  
Clinical Status ◽  
Lung Compliance ◽  
Assisted Ventilation ◽  
Pulmonary Mechanics ◽  
Neck Flexion ◽  
Position Effects ◽  
Postural Changes ◽  
Residual Capacity

Pulmonary mechanics and ventilatory parameters were measured in 30 former preterm infants at a postterm age of 8 to 10 months. All subjects had required assisted ventilation in the neonatal period and 16 had a history of bronchopulmonary dysplasia. Each infant was studied in both supine and semisitting positions, and in each body position the infants were studied with neutral, flexed, and extended neck positions. Baseline measurements (body supine, neck neutral) and the responses to postural changes did not differ between infants who had had bronchopulmonary dysplasia and those who had not. Change in body position from supine to semisitting decreased total pulmonary resistance (P < .05) and increased specific lung compliance (P < .01). Neck flexion increased resistance (P < .0001) in both body positions but did not influence compliance. These postural effects are consistent with an increase in functional residual capacity in the semisitting position and a decrease in pharyngeal area during neck flexion. Thus, posture needs to be precisely controlled during pulmonary function testing in infants. Furthermore, optimal neck and body position may improve their clinical status.

Pulmonary mechanics during the ventilatory response to hypoxemia in the newborn monkey

1983 ◽  
Vol 55 (3) ◽  
pp. 1008-1014 ◽  
Author(s):  
W. A. LaFramboise ◽  
R. D. Guthrie ◽  
T. A. Standaert ◽  
D. E. Woodrum
Keyword(s):  
Ventilatory Response ◽  
Minute Ventilation ◽  
Lung Compliance ◽  
Pulmonary Mechanics ◽  
Base Line ◽  
Respiratory Drive ◽  
Pulmonary Resistance ◽  
Residual Capacity ◽  
Dynamic Lung Compliance ◽  
Sustained Increase

Dynamic lung compliance (CL), inspiratory pulmonary resistance (RL), and functional residual capacity (FRC) were measured in 10 unanesthetized 48 h-old newborn monkeys and seven 21-day-old infant monkeys during acute exposures to an equivalent level of hypoxemia. End-expiratory airway occlusions were performed and the pressure developed by 200 ms (P0.2) was utilized as an index of central respiratory drive. P0.2 demonstrated a sustained increase throughout the period of hypoxemia on day 2 despite the fact that minute ventilation (VI) initially increased but then fell back to base-line levels. Dynamic lung compliance fell and FRC increased by 5 min of hypoxemia in the newborns. The 21-day-old monkeys exhibited a sustained increase in both VI and P0.2 throughout the hypoxic period with no change in CL and FRC. RL did not change at either postnatal age during hypoxemia. These data indicate that the neonatal monkey is subject to changes in pulmonary mechanics (decreased CL and increased FRC) during hypoxemia and that these changes are eliminated with maturation.

Canine bronchoconstriction, gas trapping, and hypoxia with methacholine

1987 ◽  
Vol 63 (1) ◽  
pp. 262-269 ◽  
Author(s):  
P. H. Breen ◽  
L. J. Becker ◽  
P. Ruygrok ◽  
I. Mayers ◽  
G. R. Long ◽  
...  
Keyword(s):  
Clinical Status ◽  
Transpulmonary Pressure ◽  
Lung Compliance ◽  
Base Line ◽  
Lung Capacity ◽  
Gas Trapping ◽  
Residual Capacity ◽  
Airways Resistance ◽  
Arterial Po2 ◽  
Boyle’S Law

The effects of an intravenous methacholine infusion on cardiovascular-pulmonary function were measured in seven mongrel dogs (22.0 +/- 2.8 kg), anesthetized with chloralose and urethan and beta-adrenergically blocked with propranolol. In a volume-displacement plethysmograph, physiological measurements were made at base line and 25 min after establishing a methacholine infusion (0.1–1.0 mg X kg-1 X h-1). Methacholine significantly (P less than 0.05) increased airways resistance (1.9 +/- 0.8 to 8.2 +/- 2.9 cmH2O X l–1 X s), decreased static lung compliance (84.7 +/- 18.5 to 48.2 +/- 9.4 ml/cmH2O), depressed arterial PO2 (81 +/- 17 to 56 +/- 10 Torr), and lowered blood pressure (132 +/- 10 to 69 +/- 18 Torr) and cardiac output (5.7 +/- 1.9 to 4.1 +/- 1.2 l/min). These effects persisted during a further 80 min of methacholine infusion conducted in five of the animals. During the initial 25-min period of methacholine, the end-expired volume (volume-displacement Krogh spirometer) rose in all animals, indicating an increase in functional residual capacity from 997 +/- 115 to 1,623 +/- 259 ml (P less than 0.0005). Analysis of pulmonary pressure-volume curves revealed no change in total lung capacity but an increase in residual volume from 489 +/- 168 to 1,106 +/- 216 ml (P less than 0.001). Thus methacholine caused 617 ml of gas trapping, which was not detected by the Boyle's law principle, presumably because gas was trapped at high transpulmonary pressure. We suggest that intravenous methacholine-induced canine bronchoconstriction, which causes gas trapping and hypoxia, may be a useful animal model of clinical status asthmaticus.

On-Line Calculation of Pulmonary Mechanics by Digital Computer

1978 ◽  
Vol 17 (04) ◽  
pp. 261-272 ◽  
Author(s):  
Y. Brault ◽  
G. Atlan ◽  
H. Lorino ◽  
A. Harf ◽  
A.-M. Lorino ◽  
...  
Keyword(s):  
Time Pressure ◽  
Lung Compliance ◽  
Pulmonary Mechanics ◽  
Close Correspondence ◽  
Standard Equipment ◽  
On Demand ◽  
On Line ◽  
The Subject ◽  
Ventilatory Mechanics ◽  
Computerized System

A system was built up around a minicomputer to process in real time pressure and flow signals collected during the course of three ventilatory mechanics tests: the calculation of the lung volume, the evaluation of the static lung compliance, the analysis of the forced expiratory performance. The subject is seated in an open body Plethysmograph, which allows for the instantaneous calculation of changes in the volume of his thorax and abdomen. The system is controlled through a graphics console which displays the sampled curves and the results of data processing. In addition, the signals can be stored on demand onto a magnetic tape so that the method can be tested and improved off line. The results obtained in healthy volunteers are highly reproducible. A close correspondence is found both in patients and volunteers between computer-derived and hand-calculated results. The computerized system has become a standard equipment of our Lung Function Department, where it allows for a rapid quantitative analysis of lung volumes, lung elasticity and bronchial airflow.

STUDIES OF RESPIRATORY PHYSIOLOGY IN CHILDREN

PEDIATRICS ◽  
1959 ◽  
Vol 24 (2) ◽  
pp. 181-193
Author(s):  
C. D. Cook ◽  
P. J. Helliesen ◽  
L. Kulczycki ◽  
H. Barrie ◽  
L. Friedlander ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Lung Compliance ◽  
Respiratory Physiology ◽  
Residual Volume ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Residual Capacity

Tidal volume, respiratory rate and lung volumes have been measured in 64 patients with cystic fibrosis of the pancreas while lung compliance and resistance were measured in 42 of these. Serial studies of lung volumes were done in 43. Tidal volume was reduced and the respiratory rate increased only in the most severely ill patients. Excluding the three patients with lobectomies, residual volume and functional residual capacity were found to be significantly increased in 46 and 21%, respectively. These changes correlated well with the roentgenographic evaluation of emphysema. Vital capacity was significantly reduced in 34% while total lung capacity was, on the average, relatively unchanged. Seventy per cent of the 61 patients had a signficantly elevated RV/TLC ratio. Lung compliance was significantly reduced in only the most severely ill patients but resistance was significantly increased in 35% of the patients studied. The serial studies of lung volumes showed no consistent trends among the groups of patients in the period between studies. However, 10% of the surviving patients showed evidence of significant improvement while 15% deteriorated. [See Fig. 8. in Source Pdf.] Although there were individual discrepancies, there was a definite correlation between the clinical evaluation and tests of respiratory function, especially the changes in residual volume, the vital capacity, RV/ TLC ratio and the lung compliance and resistance.

Effects of elastase-induced emphysema on airway responsiveness to methacholine in rats

1989 ◽  
Vol 66 (2) ◽  
pp. 606-612 ◽  
Author(s):  
S. Bellofiore ◽  
D. H. Eidelman ◽  
P. T. Macklem ◽  
J. G. Martin
Keyword(s):  
Lung Volume ◽  
Brown Norway ◽  
Pulmonary Mechanics ◽  
Maximum Increase ◽  
Before And After ◽  
Airway Response ◽  
Residual Capacity ◽  
Airway Responses ◽  
Norway Rats ◽  
Concentration Response Curve

We examined the effects of elastase-induced emphysema on lung volumes, pulmonary mechanics, and airway responses to inhaled methacholine (MCh) of nine male Brown Norway rats. Measurements were made before and weekly for 4 wk after elastase in five rats. In four rats measurements were made before and at 3 wk after elastase; in these same animals the effects of changes in end-expiratory lung volume on the airway responses to MCh were evaluated before and after elastase. Airway responses were determined from peak pulmonary resistance (RL) calculated after 30-s aerosolizations of saline and doubling concentrations of MCh from 1 to 64 mg/ml. Porcine pancreatic elastase (1 IU/g) was administered intratracheally. Before elastase RL rose from 0.20 +/- 0.02 cmH2O.ml-1.s (mean +/- SE; n = 9) to 0.57 +/- 0.06 after MCh (64 mg/ml). A plateau was observed in the concentration-response curve. Static compliance and the maximum increase in RL (delta RL64) were significantly correlated (r = 0.799, P less than 0.01). Three weeks after elastase the maximal airway response to MCh was enhanced and no plateau was observed; delta RL64 was 0.78 +/- 0.07 cmH2O.ml-1.s, significantly higher than control delta RL64 (0.36 +/- 0.7, P less than 0.05). Before elastase, increase of end-expiratory lung volume to functional residual capacity + 1.56 ml (+/- 0.08 ml) significantly reduced RL at 64 mg MCh/ml from 0.62 +/- 0.05 cmH2O.ml-1.s to 0.50 +/- 0.03, P less than 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of body position change on thoracoabdominal motion

1978 ◽  
Vol 45 (4) ◽  
pp. 581-589 ◽  
Author(s):  
V. P. Vellody ◽  
M. Nassery ◽  
W. S. Druz ◽  
J. T. Sharp
Keyword(s):  
Supine Position ◽  
Muscle Force ◽  
Body Position ◽  
Tidal Breathing ◽  
Position Change ◽  
Rib Cage ◽  
Inspiratory Muscles ◽  
Residual Capacity ◽  
Lateral Decubitus ◽  
Local Compliance

With a linearized respiratory magnetometer, measurements of anteroposterior and lateral diameters of both the rib cage and the abdomen were made at functional residual capacity and continuously during tidal breathing. Twenty-five subjects with normal respiratory systems were studied in the sitting, supine, lateral decubitus, and prone body positions. When subjects changed from sitting to supine position anteroposterior diameters of both rib cage and abdomen decreased while their lateral diameters increased. Both anteroposterior and lateral tidal excursions of the rib cage decreased; those of the abdomen increased. When subjects turned from supine to lateral decubitus position both anteroposterior diameters increased and the lateral diameters decreased. This was associated with an increase in both lateral excursions and a decrease in the abdominal anteroposterior excursions. Diameters and tidal excursions in the prone position resembled those in the supine position. Diameter changes could be explained by gravitational effects. Differences in tidal excursions accompanying body position change were probably related to 1) differences in the distribution of respiratory muscle force, 2) differences in the activity or mechanical advantage of various inspiratory muscles, and 3) local compliance changes in parts of the rib cage and abdomen.

Pulmonary Mechanics in Preterm Neonates With Respiratory Failure Treated With High-Frequency Oscillatory Ventilation Compared With Conventional Mechanical Ventilation

PEDIATRICS ◽  
1991 ◽  
Vol 87 (4) ◽  
pp. 487-493
Author(s):  
Soraya Abbasi ◽  
Vinod K. Bhutani ◽  
Alan R. Spitzer ◽  
William W. Fox
Keyword(s):  
Mechanical Ventilation ◽  
Bronchopulmonary Dysplasia ◽  
High Frequency ◽  
Conventional Mechanical Ventilation ◽  
High Frequency Oscillatory Ventilation ◽  
Preterm Neonates ◽  
High Frequency Ventilation ◽  
Pulmonary Mechanics ◽  
Frequency Ventilation ◽  
High Frequency Oscillatory

Pulmonary mechanics were measured in 43 preterm neonates (mean ± SD values of birth weight 1.2 ± 0.3 kg, gestational age 30 ± 2 weeks) with respiratory failure who were concurrently randomly assigned to receive conventional mechanical ventilation (n = 22) or high-frequency ventilation (n = 21). The incidence of bronchopulmonary dysplasia was comparable in the two groups (high-frequency ventilation 57%, conventional ventilation 50%). Pulmonary functions were determined at 0.5, 1.0, 2.0, and 4.0 weeks postnatal ages. Data were collected while subjects were in a nonsedated state during spontaneous breathing. These sequential data show similar patterns of change in pulmonary mechanics during high-frequency ventilation and conventional mechanical ventilation irrespective of gestational age, birth weight stratification, or bronchopulmonary dysplasia. There was no significant difference in the pulmonary functions with either mode of ventilation during the acute phase (≤4 weeks) of respiratory disease. When evaluated by the clinical diagnosis of bronchopulmonary dysplasia, the pulmonary data suggested a less severe dysfunction in the high-frequency oscillatory ventilation-treated bronchopulmonary dysplasia group compared with the conventional mechanical ventilation-treated group. These results indicate that high-frequency oscillatory ventilation in preterm neonates does not reduce the risk of acute lung injury; however, the magnitude of the pulmonary dysfunction in the first 2 weeks of life merits a reevaluation.

Effect of Oral Diuretics on Pulmonary Mechanics in Infants with Chronic Bronchopulmonary Dysplasia: Results of a Double-Blind Crossover Sequential Trial

PEDIATRICS ◽  
1984 ◽  
Vol 74 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Lily C. Kao ◽  
David Warburton ◽  
Mary H. Cheng ◽  
Cecilia Cedeño ◽  
Arnold C. G. Platzker ◽  
...  
Keyword(s):  
Weight Gain ◽  
Bronchopulmonary Dysplasia ◽  
Sequential Analysis ◽  
Crossover Trial ◽  
Fluid Intake ◽  
Pulmonary Mechanics ◽  
Double Blind ◽  
Phosphorus Excretion ◽  
Phosphorus Depletion ◽  
Airway Conductance

In a randomized double-blind crossover trial with sequential analysis, the effects of oral diuretics were compared with the effects of placebo on pulmonary mechanics in ten infants with bronchopulmonary dysplasia (BPD). Pulmonary mechanics were measured before and at the end of a week of treatment with oral diuretics (chlorothiazide, 20 mg/kg/dose and spironolactone, 1.5 mg/kg/dose) given twice daily, or placebo. Mean airway resistance decreased 35.3 cm H2O/L/s, mean specific airway conductance increased 0.095 1/L/s/cm H2O, and mean dynamic pulmonary compliance increased 1.74 mL/cm H2O during treatment with diuretics (all P <.001), but not during treatment with placebo. The infants' rate of weight gain decreased on the first three days of diuretic treatment, but was thereafter comparable with weight gain during treatment with placebo. Fluid intake was similar in infants receiving diuretics and placebo. But, infants receiving diuretics not only had significantly increased urine output, osmolal clearance, and potassium and phosphorus excretion, but these infants also retained less fluid, and, in addition, excreted less calcium than infants receiving placebo. It is concluded that oral diuretics improve lung function in infants with chronic bronchopulmonary dysplasia; however, potassium and phosphorus depletion are potential complications of treatment.

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