Neurally Controlled Lung Protective Ventilation By Elimination Of Upper Airway Dead Space

2011 ◽  
Author(s):  
Dajiro Takahashi ◽  
Ling Liu ◽  
Jennifer Beck ◽  
Christer Sinderby
Keyword(s):  
Dead Space ◽  
Upper Airway ◽  
Protective Ventilation ◽  
Lung Protective Ventilation ◽  
Airway Dead Space

Effect of reducing anatomic dead space on arterial PCO2 during CO2 inhalation

1986 ◽  
Vol 61 (2) ◽  
pp. 728-733 ◽  
Author(s):  
H. V. Forster ◽  
L. G. Pan ◽  
G. E. Bisgard ◽  
C. Flynn ◽  
R. E. Hoffer
Keyword(s):  
Dead Space ◽  
Pulmonary Ventilation ◽  
Upper Airway ◽  
Relative Increase ◽  
Breathing Frequency ◽  
Arterial Pco2 ◽  
Airway Dead Space ◽  
Normal Increase ◽  
Breathing Room ◽  
Sensory Mechanism

Carotid body-denervated (CBD) ponies have a less than normal increase in arterial PCO2 (PaCO2) when inspired CO2 (PICO2) is increased, even when pulmonary ventilation (VE) and breathing frequency (f) are normal. We studied six tracheostomized ponies to determine whether this change 1) might be due to increased alveolar ventilation (VA) secondary to a reduction in upper airway dead space (VD) or 2) is dependent on an upper airway sensory mechanism. Three normal and three chronic CBD ponies were studied while they were breathing room air and at 14, 28, and 42 Torr PICO2. While the ponies were breathing room air, physiological VD was 483 and 255 ml during nares breathing (NBr) and tracheostomy breathing (TBr), respectively. However, at elevated PICO2, mixed expired PCO2 often exceeded PaCO2; thus we were unable to calculate physiological VD using the Bohr equation. At all PICO2 in normal ponies, PaCO2 was approximately 0.3 Torr greater during NBr than during TBr (P less than 0.05). In CBD ponies this NBr-TBr difference was only evident while breathing room air and at 28 Torr PICO2. At each elevated PICO2 during both NBr and TBr, the increase in PaCO2 above control was always less in CBD ponies than in normal ponies (P less than 0.01). The VE-PaCO2, f-PaCO2, and tidal volume-PaCO2 relationships did not differ between NBr and TBr (P greater than 0.10) nor did they differ between normal and CBD ponies (P greater than 0.10). We conclude that the attenuated increase in PaCO2 during CO2 inhalation after CBD is not due to a relative increase in VA secondary to reducing upper airway VD.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of cardiorespiratory function using oscillating inert gas forcing signals

1994 ◽  
Vol 76 (5) ◽  
pp. 2130-2139 ◽  
Author(s):  
E. M. Williams ◽  
J. B. Aspel ◽  
S. M. Burrough ◽  
W. A. Ryder ◽  
M. C. Sainsbury ◽  
...  
Keyword(s):  
Blood Flow ◽  
Nitrous Oxide ◽  
Dead Space ◽  
Confidence Limit ◽  
Pulmonary Blood Flow ◽  
Mean Difference ◽  
Alveolar Volume ◽  
Single Breath ◽  
Cardiorespiratory Function ◽  
Airway Dead Space

A theoretical model (Hahn et al. J. Appl. Physiol. 75: 1863–1876, 1993) predicts that the amplitudes of the argon and nitrous oxide inspired, end-expired, and mixed expired sinusoids at forcing periods in the range of 2–3 min (frequency 0.3–0.5 min-1) can be used directly to measure airway dead space, lung alveolar volume, and pulmonary blood flow. We tested the ability of this procedure to measure these parameters continuously by feeding monosinusoidal argon and nitrous oxide forcing signals (6 +/- 4% vol/vol) into the inspired airstream of nine anesthetized ventilated dogs. Close agreement was found between single-breath and sinusoid airway dead space measurements (mean difference 15 +/- 6%, 95% confidence limit), N2 washout and sinusoid alveolar volume (mean difference 4 +/- 6%, 95% confidence limit), and thermal dilution and sinusoid pulmonary blood flow (mean difference 12 +/- 11%, 95% confidence limit). The application of 1 kPa positive end-expiratory pressure increased airway dead space by 12% and alveolar volume from 0.8 to 1.1 liters but did not alter pulmonary blood flow, as measured by both the sinusoid and comparator techniques. Our findings show that the noninvasive sinusoid technique can be used to measure cardiorespiratory lung function and allows changes in function to be resolved in 2 min.

scholarly journals A simple classification model for hospital mortality in patients with acute lung injury managed with lung protective ventilation*

2011 ◽  
Vol 39 (12) ◽  
pp. 2645-2651 ◽  
Author(s):  
Lisa M. Brown ◽  
Carolyn S. Calfee ◽  
Michael A. Matthay ◽  
Roy G. Brower ◽  
B. Taylor Thompson ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Hospital Mortality ◽  
Protective Ventilation ◽  
Classification Model ◽  
Lung Protective Ventilation ◽  
Simple Classification

Exhaled CO 2 , a guide to ARDS management during lung-protective ventilation?

2018 ◽  
Vol 45 ◽  
pp. 229-230
Author(s):  
Robert M. Kacmarek ◽  
Jesús Villar ◽  
Lorenzo Berra
Keyword(s):  
Protective Ventilation ◽  
Lung Protective Ventilation

scholarly journals Nasal high flow clears anatomical dead space in upper airway models

2015 ◽  
Vol 118 (12) ◽  
pp. 1525-1532 ◽  
Author(s):  
Winfried Möller ◽  
Gülnaz Celik ◽  
Sheng Feng ◽  
Peter Bartenstein ◽  
Gabriele Meyer ◽  
...  
Keyword(s):  
Dead Space ◽  
Cylindrical Tube ◽  
Upper Airway ◽  
Supplemental Oxygen ◽  
High Flow ◽  
Tube Model ◽  
Tracer Gas ◽  
Nasal Cavities ◽  
Gas Removal ◽  
Airway Model

Recent studies showed that nasal high flow (NHF) with or without supplemental oxygen can assist ventilation of patients with chronic respiratory and sleep disorders. The hypothesis of this study was to test whether NHF can clear dead space in two different models of the upper nasal airways. The first was a simple tube model consisting of a nozzle to simulate the nasal valve area, connected to a cylindrical tube to simulate the nasal cavity. The second was a more complex anatomically representative upper airway model, constructed from segmented CT-scan images of a healthy volunteer. After filling the models with tracer gases, NHF was delivered at rates of 15, 30, and 45 l/min. The tracer gas clearance was determined using dynamic infrared CO2 spectroscopy and 81mKr-gas radioactive gamma camera imaging. There was a similar tracer-gas clearance characteristic in the tube model and the upper airway model: clearance half-times were below 1.0 s and decreased with increasing NHF rates. For both models, the anterior compartments demonstrated faster clearance levels (half-times < 0.5 s) and the posterior sections showed slower clearance (half-times < 1.0 s). Both imaging methods showed similar flow-dependent tracer-gas clearance in the models. For the anatomically based model, there was complete tracer-gas removal from the nasal cavities within 1.0 s. The level of clearance in the nasal cavities increased by 1.8 ml/s for every 1.0 l/min increase in the rate of NHF. The study has demonstrated the fast-occurring clearance of nasal cavities by NHF therapy, which is capable of reducing of dead space rebreathing.

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