scholarly journals Physiological and anatomical dead space in mechanically ventilated newborn infants

2017 ◽  
Vol 53 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Theodore Dassios ◽  
Paul Dixon ◽  
Ann Hickey ◽  
Sotirios Fouzas ◽  
Anne Greenough
Keyword(s):  
Dead Space ◽  
Newborn Infants ◽  
Mechanically Ventilated ◽  
Anatomical Dead Space

Anatomical and alveolar dead space in mechanically ventilated newborn infants

2018 ◽  
Author(s):  
Theodore Dassios ◽  
Paul Dixon ◽  
Ann Hickey ◽  
Sotirios Fouzas ◽  
Anne Greenough
Keyword(s):  
Dead Space ◽  
Newborn Infants ◽  
Alveolar Dead Space ◽  
Mechanically Ventilated

A New Equal Area Method to Calculate and Represent Physiologic, Anatomical, and Alveolar Dead Spaces

2006 ◽  
Vol 104 (4) ◽  
pp. 696-700 ◽  
Author(s):  
Yongquan Tang ◽  
Martin J. Turner ◽  
A Barry Baker
Keyword(s):  
Carbon Dioxide ◽  
Dead Space ◽  
Graphical Method ◽  
Mean Difference ◽  
Equal Area ◽  
Area Method ◽  
Physiologic Dead Space ◽  
Anatomical Dead Space ◽  
The Mean ◽  
The Difference

Background Physiologic dead space is usually estimated by the Bohr-Enghoff equation or the Fletcher method. Alveolar dead space is calculated as the difference between anatomical dead space estimated by the Fowler equal area method and physiologic dead space. This study introduces a graphical method that uses similar principles for measuring and displaying anatomical, physiologic, and alveolar dead spaces. Methods A new graphical equal area method for estimating physiologic dead space is derived. Physiologic dead spaces of 1,200 carbon dioxide expirograms obtained from 10 ventilated patients were calculated by the Bohr-Enghoff equation, the Fletcher area method, and the new graphical equal area method and were compared by Bland-Altman analysis. Dead space was varied by varying tidal volume, end-expiratory pressure, inspiratory-to-expiratory ratio, and inspiratory hold in each patient. Results The new graphical equal area method for calculating physiologic dead space is shown analytically to be identical to the Bohr-Enghoff calculation. The mean difference (limits of agreement) between the physiologic dead spaces calculated by the new equal area method and Bohr-Enghoff equation was -0.07 ml (-1.27 to 1.13 ml). The mean difference between new equal area method and the Fletcher area method was -0.09 ml (-1.52 to 1.34 ml). Conclusions The authors' equal area method for calculating, displaying, and visualizing physiologic dead space is easy to understand and yields the same results as the classic Bohr-Enghoff equation and Fletcher area method. All three dead spaces--physiologic, anatomical, and alveolar--together with their relations to expired volume, can be displayed conveniently on the x-axis of a carbon dioxide expirogram.

scholarly journals Aspiration of airway dead space (ASPIDS) in mechanically ventilated patients

Critical Care ◽  
10.1186/cc213 ◽  
1998 ◽  
Vol 2 (Suppl 1) ◽  
pp. P083
Author(s):  
E De Robertis ◽  
G Servillo ◽  
F Rossano ◽  
B Jonson ◽  
R Tufano
Keyword(s):  
Dead Space ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Airway Dead Space ◽  
Ventilated Patients

Convective and diffusive gas transport in canine intrapulmonary airways

1992 ◽  
Vol 72 (4) ◽  
pp. 1557-1562 ◽  
Author(s):  
H. Schulz ◽  
P. Heilmann ◽  
A. Hillebrecht ◽  
J. Gebhart ◽  
M. Meyer ◽  
...  
Keyword(s):  
Dead Space ◽  
Gas Transport ◽  
Inert Gases ◽  
Differential Analysis ◽  
Mechanically Ventilated ◽  
Convective Mixing ◽  
Conducting Airways ◽  
And Diffusion ◽  
Residual Air ◽  
Space Dispersion

The significance of convective and diffusive gas transport in the respiratory system was assessed from the response of combined inert gas and particle boluses inhaled into the conducting airways. Particles, considered as “nondiffusing gas,” served as tracers for convection and two inert gases with widely different diffusive characteristics (He and SF6) as tracers for convection and diffusion. Six-milliliter boluses labeled with monodisperse di-2-ethylhexyl sebacate droplets of 0.86-microns aerodynamic diameter, 2% He, and 2% SF6 were inspired by three anesthetized mechanically ventilated beagle dogs to volumetric lung depths up to 170 ml. Mixing between inspired and residual air caused dispersion of the inspired bolus, which was quantified in terms of the bolus half-width. Dispersion of particles increased with increasing lung depth to which the boluses were inhaled. The increase followed a power law with exponents less than 0.5 (mean 0.39), indicating that the effect of convective mixing per unit volume was reduced with depth. Within the pulmonary dead space, the behavior of the inert gases He and SF6 was similar to that of the particles, suggesting that gas transport was almost solely due to convection. Beyond the dead space, dispersion of He and SF6 increased more rapidly than dispersion of particles, indicating that diffusion became significant. The gas and particle bolus technique offers a suitable approach to differential analysis of gas transport in intrapulmonary airways of lungs.

Immediate Effects on Lung Function of Instilled Human Surfactant in Mechanically Ventilated Newborn Infants with IRDS

1990 ◽  
Vol 79 (8-9) ◽  
pp. 750-755 ◽  
Author(s):  
K. E. EDBERG ◽  
B. EKSTRÖM-JODAL ◽  
M. HALLMAN ◽  
O. HJALMARSON ◽  
K. SANDBERG ◽  
...  
Keyword(s):  
Lung Function ◽  
Newborn Infants ◽  
Mechanically Ventilated

scholarly journals Reductions in dead space ventilation with nasal high flow depend on physiological dead space volume: metabolic hood measurements during sleep in patients with COPD and controls

2018 ◽  
Vol 51 (5) ◽  
pp. 1702251 ◽  
Author(s):  
Paolo Biselli ◽  
Kathrin Fricke ◽  
Ludger Grote ◽  
Andrew T. Braun ◽  
Jason Kirkness ◽  
...  
Keyword(s):  
Respiratory Rate ◽  
Dead Space ◽  
Minute Ventilation ◽  
High Flow ◽  
Physiological Dead Space ◽  
Copd Patients ◽  
Dead Space Volume ◽  
Anatomical Dead Space ◽  
Dead Space Ventilation ◽  
Space Volume

Nasal high flow (NHF) reduces minute ventilation and ventilatory loads during sleep but the mechanisms are not clear. We hypothesised NHF reduces ventilation in proportion to physiological but not anatomical dead space.11 subjects (five controls and six chronic obstructive pulmonary disease (COPD) patients) underwent polysomnography with transcutaneous carbon dioxide (CO2) monitoring under a metabolic hood. During stable non-rapid eye movement stage 2 sleep, subjects received NHF (20 L·min−1) intermittently for periods of 5–10 min. We measured CO2 production and calculated dead space ventilation.Controls and COPD patients responded similarly to NHF. NHF reduced minute ventilation (from 5.6±0.4 to 4.8±0.4 L·min−1; p<0.05) and tidal volume (from 0.34±0.03 to 0.3±0.03 L; p<0.05) without a change in energy expenditure, transcutaneous CO2 or alveolar ventilation. There was a significant decrease in dead space ventilation (from 2.5±0.4 to 1.6±0.4 L·min−1; p<0.05), but not in respiratory rate. The reduction in dead space ventilation correlated with baseline physiological dead space fraction (r2=0.36; p<0.05), but not with respiratory rate or anatomical dead space volume.During sleep, NHF decreases minute ventilation due to an overall reduction in dead space ventilation in proportion to the extent of baseline physiological dead space fraction.

A VALVE FOR RESPIRATORY STUDIES IN INFANTS

PEDIATRICS ◽  
1961 ◽  
Vol 27 (4) ◽  
pp. 645-647
Author(s):  
Richard J. Golinko ◽  
Abraham M. Rudolph
Keyword(s):  
Dead Space ◽  
Newborn Infants ◽  
Dilution Effect ◽  
Face Mask ◽  
The Body ◽  
Large Head ◽  
The Face ◽  
Residual Capacity ◽  
Respiratory Valve ◽  
Body Plethysmograph

PULMONARY function studies in small infants have been limited in the past by failure to develop practical methods for collecting expired gas samples. Adaption of a respiratory valve suitable for use in small subjects with small tidal volumes has been difficult and has led to the use of techniques with the body plethysmograph, contour face mask and large head chamber. The body plethysmograph offers only indirect data and requires considerable prepration before each study. In addition, it has the disadvantage that once the infant is placed in the plethysmograph chamber further manipulations of the infant are not possible. Systems using the contour face mask on head chamber involve a large dead space which may be quite significant when one considers the small volumes dealt with. In order to overcome the problem of large dead space, Cayler et al., similar to others, circulated air across the face of the contour mask. However, because of the dilution effect, differences in the composition of the inspired and expired gases were very small and therefore the chance for error in the calculations was increased. Berglund and Karlberg, and Geubelle et al., while studying functional residual capacity in infants, found that practically all quiet, healthy newborn infants breathe through the nose and can also tolerate the insertion of small tubes in their nostrils for varying periods. On the basis of these observations, a respiratory valve has been designed for insertion directly into the nostrils, permitting collection of total expired air. The valve, especially adapted for use in small infants, offers minimal resistance to respiration and has a dead space of 0.8 ml.

scholarly journals Management of hypercapnia in critically ill mechanically ventilated patients—A narrative review of literature

2020 ◽  
Vol 21 (4) ◽  
pp. 327-333
Author(s):  
Ravindranath Tiruvoipati ◽  
Sachin Gupta ◽  
David Pilcher ◽  
Michael Bailey
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Dead Space ◽  
Hypercapnic Acidosis ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Low Tidal Volume ◽  
Volume Ventilation ◽  
Low Volume ◽  
Ventilated Patients

The use of lower tidal volume ventilation was shown to improve survival in mechanically ventilated patients with acute lung injury. In some patients this strategy may cause hypercapnic acidosis. A significant body of recent clinical data suggest that hypercapnic acidosis is associated with adverse clinical outcomes including increased hospital mortality. We aimed to review the available treatment options that may be used to manage acute hypercapnic acidosis that may be seen with low tidal volume ventilation. The databases of MEDLINE and EMBASE were searched. Studies including animals or tissues were excluded. We also searched bibliographic references of relevant studies, irrespective of study design with the intention of finding relevant studies to be included in this review. The possible options to treat hypercapnia included optimising the use of low tidal volume mechanical ventilation to enhance carbon dioxide elimination. These include techniques to reduce dead space ventilation, and physiological dead space, use of buffers, airway pressure release ventilation and prone positon ventilation. In patients where hypercapnic acidosis could not be managed with lung protective mechanical ventilation, extracorporeal techniques may be used. Newer, minimally invasive low volume venovenous extracorporeal devices are currently being investigated for managing hypercapnia associated with low and ultra-low volume mechanical ventilation.

Uneven gas mixing during rebreathing assessed by simultaneously measuring dead space

1982 ◽  
Vol 53 (4) ◽  
pp. 930-939 ◽  
Author(s):  
M. F. Petrini ◽  
B. T. Peterson ◽  
R. W. Hyde ◽  
V. Lam ◽  
M. J. Utell ◽  
...  
Keyword(s):  
Dead Space ◽  
Sulfur Hexafluoride ◽  
Breath Holding ◽  
Gas Mixing ◽  
Pulmonary Tissue ◽  
Pulmonary Capillary Blood Flow ◽  
Pulmonary Capillary Blood ◽  
Anatomical Dead Space ◽  
The Difference ◽  
Uneven Ventilation

To evaluate the rate of gas mixing in human lungs during rebreathing maneuvers used to measure pulmonary tissue volume (Vt) and pulmonary capillary blood flow (Qc), we devised a method to determine the dead space during rebreathing (VRD). Required measurements are initial concentration of a foreign inert insoluble gas in the rebreathing bag, first mixed expired concentration, equilibrated concentration, volume inspired, and volume of the first expired breath. In subjects breathing rapidly at 30 breaths/min with inspired volumes in excess of 2 liters, VRD had values three or more times greater than the predicted anatomical dead space (VD). Breath holding after the first inspiration progressively diminished VRD so that after 10–15 s, it approximately equaled predicted VD. VRD measured with helium was smaller than VRD measured with sulfur hexafluoride. The reported degree of uneven ventilation from gravitational forces in normal humans can account for only about one-third of the difference between VRD and VD. These findings support the concept that mixing by diffusion between peripheral parallel airways is incomplete at normal breathing rates in humans and can result in errors as high as 25% in Vt and Qc.

Relation between anatomic respiratory dead space and body size and lung volume

1963 ◽  
Vol 18 (3) ◽  
pp. 519-522 ◽  
Author(s):  
M. C. Hart ◽  
M. M. Orzalesi ◽  
C. D. Cook
Keyword(s):  
Surface Area ◽  
Functional Residual Capacity ◽  
Dead Space ◽  
Technical Assistance ◽  
Newborn Infants ◽  
Early Period ◽  
Somatic Growth ◽  
Normal Subjects ◽  
Significant Difference ◽  
Residual Capacity

The respiratory anatomic dead space has been measured by the single breath nitrogen washout method of Fowler in 73 normal subjects ranging from 4 to 42 years of age. The volume of the anatomic dead space correlated closely with height (Vd (ml) = 7.585 x Ht (cm)2.363 x 10-4·ɣ = .917), but also with body weight, surface area, and functional residual capacity. When compared on the basis of any of these parameters there was no significant difference between the anatomic dead space values for males and females. Comparisons with available data for newborn infants suggest that the value of the anatomic dead space has a relatively constant relation to height from birth to adulthood. Dead space appears to increase more rapidly than weight, surface area, and functional residual capacity during, at least, the early period of somatic growth. Note: (With the Technical Assistance of J. H. Shaw) Submitted on October 25, 1962

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