Definition and clinical evaluation of a recruiting airway pressure based on the specific lung elastance in anesthetized dogs

2021 ◽  
Author(s):  
Joaquin Araos ◽  
Luca Lacitignola ◽  
Claudia Acquafredda ◽  
Caterina DiBella ◽  
Marzia Stabile ◽  
...  
Keyword(s):  
Clinical Evaluation ◽  
Airway Pressure ◽  
Lung Elastance ◽  
Anesthetized Dogs

Inspiratory and expiratory muscle function during continuous positive airway pressure in dogs

1990 ◽  
Vol 68 (3) ◽  
pp. 1092-1100 ◽  
Author(s):  
J. D. Road ◽  
A. M. Leevers
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Initial Length ◽  
Active Components ◽  
Tidal Breathing ◽  
Expiratory Muscle ◽  
Anesthetized Dogs ◽  
Inspiratory Activity ◽  
Expiratory Muscles

Continuous positive airway pressure (CPAP) is known to produce activation of the expiratory muscles. Several factors may determine whether this activation can assist inspiration. In this study we asked how and to what extent expiratory muscle contraction can assist inspiration during CPAP. Respiratory muscle response to CPAP was studied in eight supine anesthetized dogs. Lung volume and diaphragmatic initial length were defended by recruitment of the expiratory muscles. At the maximum CPAP of 18 cmH2O, diaphragmatic initial lengths were longer than predicted by the passive relationship by 52 and 46% in the costal and crural diaphragmatic segments, respectively. During tidal breathing after cessation of expiratory muscle activity, a component of passive inspiration occurred before the onset of inspiratory diaphragmatic electromyogram (EMG). At CPAP of 18 cmH2O, passive inspiration represented 24% of the tidal volume (VT) and tidal breathing was within the relaxation characteristic. Diaphragmatic EMG decreased at CPAP of 18 cmH2O; however, VT and tidal shortening were unchanged. We identified passive and active components of inspiration. Passive inspiration was limited by the time between the cessation of expiratory activity and the onset of inspiratory activity. We conclude that increased expiratory activity during CPAP defends diaphragmatic initial length, assists inspiration, and preserves VT. Even though breathing appeared to be an expiratory act, there remained a significant component of active inspiratory diaphragmatic shortening, and the major portion of VT was produced during active inspiration.

Clinical evaluation of arterial blood pressure in anesthetized dogs by use of a veterinary-specific multiparameter monitor

2020 ◽  
Vol 81 (8) ◽  
pp. 635-641
Author(s):  
Zoë R. Jacobs-Fohrman ◽  
Tamsin S. Barnes ◽  
Margaret M. McEwen ◽  
Wendy A. Goodwin
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Clinical Evaluation ◽  
Arterial Blood ◽  
Anesthetized Dogs

Cigarette smoke-induced bronchoconstriction in dogs: vagal and extravagal mechanisms

1984 ◽  
Vol 57 (4) ◽  
pp. 1261-1270 ◽  
Author(s):  
J. Hartiala ◽  
C. Mapp ◽  
R. A. Mitchell ◽  
R. L. Shields ◽  
W. M. Gold
Keyword(s):  
Smooth Muscle ◽  
Cigarette Smoke ◽  
Airway Smooth Muscle ◽  
Airway Pressure ◽  
Muscle Tone ◽  
Motor Nerve ◽  
Respiratory Center ◽  
Airway Response ◽  
Anesthetized Dogs

We reassessed the severity of cigarette smoke-induced bronchoconstriction and the mechanisms involved in anesthetized dogs. To evaluate the severity of smoke-induced bronchoconstriction, we measured airway pressure and airflow resistance (Rrs, forced oscillation method). We studied the mechanisms in other dogs by measuring airway pressure, central airway smooth muscle tone in tracheal segments in situ, and respiratory center drive by monitoring phrenic motor nerve output, including the role of vagal and extravagal nerves vs. the role of blood-borne materials during inhalation of cigarette smoke. Rrs increased more than fourfold with smoke from one cigarette delivered in two tidal volumes. About half the airway response was due to local effects of smoke in the lungs. The remainder was due to stimulation of the respiratory center, which activated vagal motor efferents to the airway smooth muscle. Of this central stimulation, about half was due to blood-borne materials and the rest to vagal pulmonary afferents from the lungs. We conclude that inhalation of cigarette smoke in dogs causes severe bronchoconstriction which is mediated mainly by extravagal mechanisms.

Soft palate muscle responses to negative upper airway pressure

1999 ◽  
Vol 86 (2) ◽  
pp. 523-530 ◽  
Author(s):  
T. C. Amis ◽  
N. O’Neill ◽  
J. R. Wheatley ◽  
T. van der Touw ◽  
E. di Somma ◽  
...  
Keyword(s):  
Soft Palate ◽  
Muscle Activity ◽  
Airway Pressure ◽  
Upper Airway ◽  
Emg Activity ◽  
Afferent Activity ◽  
Afferent Pathways ◽  
Levator Veli Palatini ◽  
Anesthetized Dogs ◽  
Muscle Responses

The afferent pathways and upper airway receptor locations involved in negative upper airway pressure (NUAP) augmentation of soft palate muscle activity have not been defined. We studied the electromyographic (EMG) response to NUAP for the palatinus, tensor veli palatini, and levator veli palatini muscles in 11 adult, supine, tracheostomized, anesthetized dogs. NUAP was applied to the nasal or laryngeal end of the isolated upper airway in six dogs and to four to six serial upper airway sites from the nasal cavity to the subglottis in five dogs. When NUAP was applied at the larynx, peak inspiratory EMG activity for the palatinus and tensor increased significantly ( P< 0.05) and plateaued at a NUAP of −10 cmH2O. Laryngeal NUAP failed to increase levator activity consistently. Nasal NUAP did not increase EMG activity for any muscle. Consistent NUAP reflex recruitment of soft palate muscle activity only occurred when the larynx was exposed to the stimulus and, furthermore, was abolished by bilateral section of the internal branches of the superior laryngeal nerves. We conclude that soft palate muscle activity may be selectively modulated by afferent activity originating in the laryngeal and hypopharyngeal airway.

Unilateral acute lung injury induced by ethchlorvynol in anesthetized dogs

1984 ◽  
Vol 56 (5) ◽  
pp. 1252-1259 ◽  
Author(s):  
A. H. Stephenson ◽  
R. S. Sprague ◽  
T. E. Dahms ◽  
A. J. Lonigro
Keyword(s):  
Blood Flow ◽  
Acute Lung Injury ◽  
Lung Injury ◽  
Airway Pressure ◽  
Left Lung ◽  
Arterial Occlusion ◽  
Peak Airway Pressure ◽  
Lung Water ◽  
Injured Lung ◽  
Anesthetized Dogs

Ethchlorvynol (ECV) was used to induce unilateral acute lung injury in anesthetized dogs. Measurements of extravascular thermal volume by double-indicator (thermal-dye) dilution with and without left main pulmonary arterial occlusion permitted sequential estimates of extravascular lung water (EVLW) for each lung. Determinations of EVLW by thermal-dye and gravimetric methods were highly correlated (r = 0.80). ECV (9–15 mg/kg) administered into the right pulmonary circulation produced progressive increases in right lung EVLW, which by 120 min post-ECV was increased 152 +/- 22% (SE) over control (P less than 0.001). Left lung EVLW remained unchanged. Similarly, right, but not left, peak airway pressure was increased. Thermal dilution, coupled with electromagnetic methods, permitted estimates of blood flow to each lung. Despite redistribution of flow to the uninjured lung, systemic PO2 decreased (P less than 0.001) and venous admixture increased (P less than 0.05), suggesting impaired matching of ventilation and perfusion. In summary, introduction of ECV into one lung produced unilateral acute lung injury. EVLW increased solely in the injured lung as did peak airway pressure. Although there was a partial redistribution of blood flow away from the injured lung to the uninjured one, it was apparently inadequate to prevent impaired oxygenation of the blood.

Description and clinical evaluation of a new continuous positive airway pressure device

1981 ◽  
Vol 9 (2) ◽  
pp. 109-113 ◽  
Author(s):  
BARRY G. ZAMOST ◽  
DAVID D. ALFERY ◽  
INGE JOHANSON ◽  
EDWIN L. GLAZENER ◽  
FRANK R. TROUSDALE ◽  
...  
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Clinical Evaluation ◽  
Airway Pressure ◽  
Positive Airway Pressure

Continuous Positive Airway Pressure (CPAP) Therapy for the Treatment of Hypernasality: A Single Case Study

2014 ◽  
Vol 24 (2) ◽  
pp. 48-58 ◽  
Author(s):  
Lakshmi Kollara ◽  
Graham Schenck ◽  
Jamie Perry
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Single Case ◽  
Treatment Method ◽  
Post Treatment ◽  
Subjective Perception ◽  
Cpap Therapy ◽  
Long Term Follow Up

Studies have investigated the applications of Continuous Positive Airway Pressure (CPAP) therapy in the treatment of hypernasality due to velopharyngeal dysfunction (VPD; Cahill et al., 2004; Kuehn, 1991; Kuehn, Moon, & Folkins, 1993; Kuehn et al., 2002). The purpose of this study was to examine the effectiveness of CPAP therapy to reduce hypernasality in a female subject, post-traumatic brain injury (TBI) and pharyngeal flap, who presented with signs of VPD including persistent hypernasality. Improvements in mean velopharyngeal orifice size, subjective perception of hypernasality, and overall intelligibility were observed from the baseline to 8-week post-treatment assessment intervals. Additional long-term assessments completed at 2, 3, and 4 months post-treatment indicated decreases in immediate post-treatment improvements. Results from the present study suggest that CPAP is a safe, non-invasive, and relatively conservative treatment method for reduction of hypernasality in selected patients with TBI. More stringent long-term follow up may indicate the need for repeated CPAP treatment to maintain results.

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