Effect of upper airway CO2 on breathing in awake ponies

1985 ◽  
Vol 59 (4) ◽  
pp. 1222-1227 ◽  
Author(s):  
H. V. Forster ◽  
L. G. Pan ◽  
C. Flynn ◽  
G. E. Bisgard ◽  
R. E. Hoffer
Keyword(s):  
Endotracheal Tube ◽  
Environmental Temperature ◽  
Upper Airway ◽  
Gas Mixture ◽  
Upper Airways ◽  
Co2 Gas ◽  
Arterial Pco2 ◽  
Cuffed Endotracheal Tube ◽  
Breathing Room ◽  
Sensory Mechanism

We determined whether the [CO2] in the upper airways (UA) can influence breathing in ponies and whether UA [CO2] contributes to the attenuation of a thermal tachypnea during periods of elevated inspired CO2. Six ponies were studied 1 mo after chronic tracheostomies were created. For one protocol the ponies were breathing room air through a cuffed endotracheal tube. Another smaller tube was placed in the tracheostomy and directed up the airway. By use of this tube, a pump, and prepared gas mixtures, UA [CO2] was altered without affecting alveolar or arterial PCO2. When the ponies were at a neutral environmental temperature (TA) and breathing frequency (f) was 8 breaths X min-1, increasing UA [CO2] up to 18–20% had no effect on f. However, when TA was increased 20 degrees C to increase f to 50 breaths X min-1, then increasing UA [CO2] to 6% or to 18–20% reduced f by 5 +/- 1.7 (SE) and 12 +/- 1.6 breaths X min-1, respectively (t = 3.3, P less than 0.01). These data suggest that in the pony there exists a UA CO2-H+ sensory mechanism. For a second protocol the ponies were breathing a 6% CO2 gas mixture for 15 min in the normal fashion over the entire airway (nares breathing, NBr) or they were breathing this gas mixture for 15 min through the cuffed endotracheal tube (TBr). At a neutral TA, increasing inspired [CO2] to 6% resulted in a 6-breaths X min-1 increase in f during both NBr and TBr.

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)

Intrapulmonary Drug Administration during High Frequency Jet Ventilation

1985 ◽  
Vol 1 (S1) ◽  
pp. 220-222 ◽  
Author(s):  
M. Klain ◽  
H. Keszler ◽  
U. Nordin ◽  
R. Kalla
Keyword(s):  
Endotracheal Tube ◽  
High Frequency ◽  
Jet Stream ◽  
Cricothyroid Membrane ◽  
Inspiratory Time ◽  
Jet Ventilation ◽  
Upper Airways ◽  
Cuffed Endotracheal Tube ◽  
Peripheral Airways ◽  
High Frequency Jet Ventilation

It has previously been demonstrated that high frequency jet ventilation, via transtracheal cricothyroid membrane puncture, can maintain good gas exchange even during cardiopulmonary resuscitation. When the upper airways were filled with fluid, aspiration could be prevented without a cuffed endotracheal tube when respiratory rates of 100/min or higher and an inspiratory time of at least 50% were used. We have also shown that cricothyroid membrane puncture is relatively easy to perform and produces less tracheal damage than a cuffed endotracheal tube.In one of our studies, cardio-green dye was mixed into the jet using a Y-connector on the proximal end of the angiocath cannula (Figure 1). In two dogs, the distribution of the dye in the lungs was investigated. It was found that nebulized dye was transported by the jet stream to the most distant bronchi which could be observed. On subsequent autopsy, the dye was found in the most peripheral airways.

scholarly journals Possible Effects of Air Temperature on COVID-19 Disease Severity and Transmission Rates

2021 ◽  
Author(s):  
Dominique Kang ◽  
Clifford Ellgen ◽  
Erik Kulstad
Keyword(s):  
Air Temperature ◽  
Upper Airway ◽  
The Body ◽  
Rapid Progression ◽  
Upper Airways ◽  
Viral Growth ◽  
Progression Of Disease ◽  
Breathing Room ◽  
Efficient Transmission

Currently available data are consistent with increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication at temperatures encountered in the upper airways (25–33°C when breathing room temperature air, 25°C) compared to those in the lower airways (37°C). One factor that may contribute to more rapid viral growth in the upper airways is the exponential increase in SARS-CoV-2 stability that occurs with reductions in temperature, as measured in vitro. Because SARS-CoV-2 frequently initiates infection in the upper airways before spreading through the body, increased upper airway viral growth early in the disease course may result in more rapid progression of disease and potentially contribute to more severe outcomes. Similarly, higher SARS-CoV-2 viral titer in the upper airways likely supports more efficient transmission. Conversely, the possible significance of air temperature to upper airway viral growth suggests that prolonged delivery of heated air might represent a preventative measure and prophylactic treatment for coronavirus disease 2019.

scholarly journals Experimental Study on Compatibility of Eco-Friendly Insulating Medium C5F10O/CO2 Gas Mixture With Copper and Aluminum

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 83994-84002 ◽  
Author(s):  
Yalong Li ◽  
Yue Zhang ◽  
Yi Li ◽  
Feng Tang ◽  
Qishen Lv ◽  
...  
Keyword(s):  
Experimental Study ◽  
Gas Mixture ◽  
Co2 Gas

Motor responses to positive-pressure breathing in the developing opossum

1985 ◽  
Vol 58 (5) ◽  
pp. 1489-1495 ◽  
Author(s):  
J. P. Farber
Keyword(s):  
Airway Resistance ◽  
Upper Airway ◽  
Abdominal Muscle ◽  
Positive Pressure ◽  
Postnatal Life ◽  
Abdominal Muscles ◽  
Upper Airways ◽  
Motor Responses ◽  
Upper Airway Resistance ◽  
Upper Airway Muscles

The suckling opossum exhibits an expiration-phased discharge in abdominal muscles during positive-pressure breathing (PPB); the response becomes apparent, however, only after the 3rd-5th wk of postnatal life. The purpose of this study was to determine whether the early lack of activation represented a deficiency of segmental outflow to abdominal muscles or whether comparable effects were observed in cranial outflows to muscles of the upper airways due to immaturity of afferent and/or supraspinal pathways. Anesthetized suckling opossums between 15 and 50 days of age were exposed to PPB; electromyogram (EMG) responses in diaphragm and abdominal muscles were measured, along with EMG of larynx dilator muscles and/or upper airway resistance. In animals older than approximately 30 days of age, the onset of PPB was associated with a prolonged expiration-phased EMG activation of larynx dilator muscles and/or decreased upper airway resistance, along with expiratory recruitment of the abdominal muscle EMG. These effects persisted as long as the load was maintained. Younger animals showed only those responses related to the upper airway; in fact, activation of upper airway muscles during PPB could be associated with suppression of the abdominal motor outflow. After unilateral vagotomy, abdominal and upper airway motor responses to PPB were reduced. The balance between PPB-induced excitatory and inhibitory or disfacilitory influences from the supraspinal level on abdominal motoneurons and/or spinal processing of information from higher centers may shift toward net excitation as the opossum matures.

Improved chamber for the isolation of anaerobic microorganisms

1976 ◽  
Vol 4 (1) ◽  
pp. 40-45
Author(s):  
M E Cox ◽  
J I Mangels
Keyword(s):  
Anaerobic Bacteria ◽  
Gas Mixture ◽  
Anaerobic Conditions ◽  
Co2 Gas ◽  
Anaerobic Microorganisms ◽  
The Media ◽  
To Receive ◽  
Latex Rubber

A small portable chamber for the recovery of anaerobic bacteria is described. This rigid chamber is constructed of clear acrylic with dimensions of 30 inches (ca. 76.2 cm) wide, 18 inches (ca. 44.7 cm) deep, and 18 inches (ca. 44.7 cm) high. Conventional bacteriological techniques can be used inside the chamber to efficiently isolate strict anaerobic organisms. An adapter allows the attachment of a standard anaerobic jar to the outside of the chamber. The jar can be used to store reduced media. Once the jar is attached to the chamber and the media is removed to the interior of the chamber, the jar is available to receive inoculated media. The anaerobic jar can then be removed from the chamber, without contaminating the jar or chamber with oxygen, and be placed in a conventional 37degreesC incubator. This chamber also allows the microbiologist to process cultures without wearing gloves as was necessary with previous anaerobic chambers. Air-tight latex rubber sleeves seal around the microbiologists arms and to the armport flange of the chamber to prevent the introduction of oxygen into the chamber. Anaerobic conditions are maintained by circulating a 80% N2, 10% H2, 10% CO2 gas mixture through alumina pellets coated with palladium. This study indicates that anaerobic conditions obtained in this chamber are sufficient for recovery of obligate anaerobes.

Inspiratory coactivation of the genioglossus enlarges retroglossal space in laryngectomized humans

1996 ◽  
Vol 80 (5) ◽  
pp. 1595-1604 ◽  
Author(s):  
I. Kobayashi ◽  
A. Perry ◽  
J. Rhymer ◽  
B. Wuyam ◽  
P. Hughes ◽  
...  
Keyword(s):  
Upper Airway ◽  
Dependent Manner ◽  
Tongue Movement ◽  
Forward Movement ◽  
Upper Airways ◽  
Posterior Aspect ◽  
Airway Patency ◽  
Significant Movement ◽  
Tongue Position ◽  
Tracheal Stoma

To investigate the relationship between the electrical activity of the genioglossus (GG-EMG) and associated tongue movement, seven laryngectomized subjects breathing through a tracheal stoma (without pressure or flow change in the upper airway) were studied in the supine position. Tongue movement, with the use of lateral fluoroscopy, and GG-EMG expressed as a percentage of maximum voluntary genioglossal activation were monitored simultaneously during 1) spontaneous inspiration (SI), 2) resistive loaded inspiration (LI), and 3) rapid inspiration (RI). Tongue position during each maneuver was compared with its position during spontaneous expiration. Peak GG-EMG during the three maneuvers was significantly different from each other (SI: 5.4 +/- 1.6, LI: 11.9 +/- 1.8, and RI: 51.6 +/- 9.4 (SE) %, respectively). Associated forward movement of the posterior aspect of the tongue was minimum during SI; however, significant movement was observed during LI, and this was increased during RI. Significant covariance existed between peak GG-EMG and this movement. Genioglossal coactivation with inspiration enlarges the glossopharyngeal airway, particularly in its caudal part. In subjects with intact upper airways, this activation may protect or enhance upper airway patency in an effort-dependent manner.

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