Developmental Alterations in Pulmonary Function of the Lamb

Shaffer, Thomas H.; Wolfson, Marla R.; Forman, Debra L.

doi:10.1159/000194759

Cited by 14 publications

(12 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These include an increase in the volume, compliance, and conductance of the lung and a decrease in the resistance, specific conductance, and compliance of the airways with maturity. The increase in lung volume, which occurs as a function of both age and body weight, is necessary to support the functional and metabolic requirements associated with growth and is attributed to alveolarization as well as an increase in airway dimensions (6,7). The greater lung volume in older neonates also contributes to the improved lung compliance seen with maturity, which in turn depends mainly on the anatomical and biochemical maturation of the respiratory apparatus.…”

Section: Discussionmentioning

confidence: 99%

“…These studies indicate that the airways from preterm neonates are highly compliant and collapsible structures that become stiffer and better able to withstand pressure-induced deformation with increasing maturity. The greater collapsibility of the immature airways predisposes premature infants to subsequent abnormalities of pulmonary function such as increased dead space with gas trapping, poor gas exchange, increased airway resistance, and increased work of breathing (5,7).…”

Section: Gag Glycosaminoglycanmentioning

confidence: 99%

See 1 more Smart Citation

Developmental Changes in Tracheal Structure

et al. 1991

View full text Add to dashboard Cite

ABSTRACT. Mechanical properties of the proximal airways are known to change with development; the highly compliant airways of the immature animal become stiffer and less collapsible with increasing age. Although the relationship between tracheobronchial architecture and function has been described for adult physiology, little is known regarding this relationship during early development. This study was, therefore, designed to test the hypothesis that alterations in tracheal morphometry parallel developmental differences in tracheal functional properties. Tracheal segments obtained from 29 lambs ranging in age from 70% of gestation to full-term newborn lambs up to 6 d old were examined using anatomic, morphometric, and histochemical techniques. The results showed 1 ) progressive increases in the dimensions of the trachea and the tracheal wall components, 2) alterations in the geometric arrangement of the tracheal ring, and 3) changes in the compositional characteristics of the tracheal cartilage with maturation. These findings demonstrate alterations in tracheal architecture, each of which contribute to the greater stiffness of the trachea, in older animals. When considered together, these factors help explain the differences in tracheal functional characteristics with development. (Pediatr Res 30: 170-175,1991) Abbreviations GAG, glycosaminoglycan Several investigators have examined the mechanical properties of the developing airways, both in humans and in various animal species (1-6). These studies indicate that the airways from preterm neonates are highly compliant and collapsible structures that become stiffer and better able to withstand pressure-induced deformation with increasing maturity. The greater collapsibility of the immature airways predisposes premature infants to subsequent abnormalities of pulmonary function such as increased dead space with gas trapping, poor gas exchange, increased airway resistance, and increased work of breathing (5, 7).The functional properties of the adult tracheobronchial tree are known to reflect variations in the anatomical structure of the tracheobronchial wall (2,3,(8)(9)(10). There is, however, little information regarding the structural basis for the differences in the functional properties of the airways during early development.Mechanical properties of the trachea have been extensively evaluated (1-5, 8, 1 1 -15). To test the hypothesis that alterations in tracheal structure parallel developmental differences in tracheal functional characteristics, we examined tracheal structure over a range of development from 70% of gestation to the neonatal period. Anatomic, morphometric, and histochemical techniques were used to study and quantify tracheal structural characteristics from preterm and full-term newborn lambs. Correlation of these findings with existing information on tracheal mechanics may aid in understanding how the premature infant differs from the full-term neonate with regard to airway structure function. MATERIALS AND METHODSTracheal segments (2-3 cm in ...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Gag Glycosaminoglycanmentioning

confidence: 99%

Developmental Changes in Tracheal Structure

et al. 1991

View full text Add to dashboard Cite

show abstract

“…A fully instrumented preterm lamb model was used to illustrate the worst case scenario. This severely immature, fragile animal has premature physiological systems and large fluid requirements due to significant transdermal fluid losses [20][21][22]. At this gestational age the lamb does not yet have a protective hide or fur for thermal insulation and to decrease some of these evaporative losses.…”

Section: Discussionmentioning

confidence: 99%

“…As previously described [20][21][22], dated pregnant ewes were preanesthesized with ketamine (1.5 mg/kg), followed by epidural anesthesia induction with 0.75% bupivicaine (0.5-1.0 mg/kg). Each ewe was blindfolded and restrained in a sidelying position and a Cesarean section was performed through the ventrolateral approach.…”

Section: Animal Preparationmentioning

confidence: 99%

“…C550 infant Isolette: convective heater, 450 W; skin temperature range, 34-39°C; lamb skin temperature set point, 38°C, skin temperature probe accuracy, B 0.3°C, resolution, 0.1°C; air temperature range, 20-39°C; lamb air temperature set point, 38°C; air temperature probe accuracy, B 0.5°C, resolution, 0.1°C. (Note that lamb core temperature is 39°C [19][20][21], and that ambient room temperature for all experiments was 27.3-27.6°C.…”

Section: Thermal Devicesmentioning

confidence: 99%

See 1 more Smart Citation

Temperature and Heater Responses during Transition between Radiant and Incubator Thermal Environment in Newborn Preterm Lambs

Touch

Greenspan²,

Cullen³

et al. 2001

Neonatology

Self Cite

View full text Add to dashboard Cite

Objective: Although both incubators and radiant warmer beds can provide thermal support to infants in the neonatal intensive care unit, the transition between devices can be a stressful event. The goal of this study was to evaluate a new device that combines these methods of warming and converts between them without requiring physical movement of the infant. Study Design: Twin preterm lambs received thermal support from a radiant warmer bed and an incubator (control), or from the Versalet^TM 7700 Care Center (treatment) in the warmer and incubator configurations. Temperature of each lamb, as well as device heater power, were monitored every 2 min before, during, and after the transition. Physiological parameters were monitored every 15 min. Results: There was a significant difference in response time between closed-open and open-closed conditions for both groups. More adverse events occurred in the control group during transfers. There were no differences in temperatures or physiological variables during transitions in either group. Conclusions: These data suggest the Versalet provides similar thermal stability to traditional devices, with fewer adverse events associated with the lack of physical movement between warming configurations. The impact of this device on the care of the preterm neonate will be evaluated in a clinical trial.

show abstract

Pharmaceuticals and Other Biomedical Applications

Kirsch

2013

Modern Fluoroorganic Chemistry

View full text Add to dashboard Cite

Developmental Alterations in Pulmonary Function of the Lamb

Cited by 14 publications

References 16 publications

Developmental Changes in Tracheal Structure

Developmental Changes in Tracheal Structure

Temperature and Heater Responses during Transition between Radiant and Incubator Thermal Environment in Newborn Preterm Lambs

Pharmaceuticals and Other Biomedical Applications

Contact Info

Product

Resources

About