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.

Reflex changes in tracheal smooth muscle tone during high-frequency oscillation

1990 ◽  
Vol 68 (2) ◽  
pp. 714-719
Author(s):  
G. C. Man ◽  
K. K. Teo ◽  
C. T. Kappagoda ◽  
S. F. Man
Keyword(s):  
Smooth Muscle ◽  
High Frequency ◽  
Airway Resistance ◽  
Muscle Tone ◽  
Muscle Tension ◽  
Upper Airway ◽  
Tracheal Smooth Muscle ◽  
High Frequency Oscillation ◽  
Positive Pressure ◽  
Upper Airway Resistance

We examined the effect of high-frequency oscillatory ventilation (HFOV) on tracheal smooth muscle tension and upper airway resistance in anesthetized dogs. The animals were ventilated via a low tracheostomy by HFOV or conventional intermittent positive pressure ventilation (IPPV) with and without added positive end-expiratory pressure (PEEP). The transverse muscle tension of the trachea above the tracheostomy was measured and found to be lower during HFOV when compared with IPPV or IPPV with PEEP. When both vagi were cooled to 8 degrees C to interrupt afferent traffic from the lungs, there was no longer any difference between the modes of ventilation. In a second series of experiments, the airflow resistance of the upper airway above the tracheostomy was measured (Ruaw). During HFOV, Ruaw was significantly lower than during either IPPV or IPPV with PEEP. We conclude that HFOV induces a relaxation of tracheal smooth muscle and a reduction of upper airway resistance through a vagally mediated mechanism.

ID: 127: DECREASED CPAP ADHERENCE IN NON-OBESE OSA PATIENTS WITH REVERSIBLE UPPER AIRWAY OBSTRUCTION

2016 ◽  
Vol 64 (4) ◽  
pp. 970.1-970
Author(s):  
J Doumit ◽  
P Belvitch ◽  
I Rubinstein
Keyword(s):  
Airway Obstruction ◽  
Airway Resistance ◽  
Upper Airway ◽  
Upper Airway Obstruction ◽  
Beta Agonist ◽  
Upper Airways ◽  
Short Acting ◽  
Cpap Adherence ◽  
Upper Airway Resistance ◽  
Airways Obstruction

RationaleUpper airway resistance is critical to the pathophysiology of obstructive sleep apnea (OSA). We have previously characterized a subset of patients with OSA who have evidence of reversible upper airways resistance as measured by spirometry. Specifically, these patients have an increased FEF50/FIF50 ratio which decreases with administration of a short acting bronchodilator. On average these patients had a lower BMI (average 27) compared to OSA patients as a whole suggesting the possibility of unique upper airway pathophysiology among this group. In the current study, we identify additional patients with OSA who have reversible upper airways obstruction on spirometry and characterize their compliance with CPAP therapy as compared to a traditional OSA population.MethodsWe retrospectively evaluated patients who had a sleep screen suggestive of OSA in the last 2 years. Patients who also had spirometry in the previous 5 years were identified for further analysis. Those patients with either normal spirometry or fixed obstructive defects who had a decrease in the FEF50/FIF50 ratio after administration of a short acting inhaled beta agonist (albuterol) were then characterized. We then measured objective CPAP adherence using data downloaded from the positive airway pressure device with adherence defined as CPAP use >4 hrs more than 70% of nights over a 30 day period.ResultsWe identified 70 patients with positive sleep screens who also had spirometry demonstrating normal of fixed lower expiratory obstruction with evidence of upper airways obstruction as demonstrated by a decreased FEF50/FIF50 ratio. Of these, 45 had a decrease in the FEF50/FIF50 ratio of more than 20% following administration of inhaled albuterol. Overall, CPAP adherence between those with reversible upper airways obstruction and those without was similar (23/45=51% vs 14/26=54%). However, subgroup analysis revealed a lower adherence rate among non-obese patients (BMI<30) with reversible airways obstruction (6/16=36%).ConclusionThe identification of a subset of patients with OSA who have evidence of decreased upper airway resistance in response to inhaled bronchodilator suggests unique pathology in this group. Decreased adherence to traditional OSA therapy with CPAP among these patients is additional evidence of differential pathophysiology requiring novel treatments. Specifically, treatment with a long acting beta agonist (LABA) prior to sleep may reduce upper airway obstruction and be better tolerated than CPAP.

Responses to negative pressure surrounding the neck in anesthetized animals

1990 ◽  
Vol 68 (1) ◽  
pp. 154-160 ◽  
Author(s):  
A. D. Wolin ◽  
K. P. Strohl ◽  
B. N. Acree ◽  
J. M. Fouke
Keyword(s):  
Negative Pressure ◽  
Airway Resistance ◽  
Upper Airway ◽  
Transmural Pressure ◽  
Positive Pressure ◽  
Respiratory Drive ◽  
Airway Wall ◽  
Airway Patency ◽  
Upper Airway Resistance ◽  
Continuous Positive Pressure

Continuous positive pressure applied at the nose has been shown to cause a decrease in upper airway resistance. The present study was designed to determine whether a similar positive transmural pressure gradient, generated by applying a negative pressure at the body surface around the neck, altered upper airway patency. Studies were performed in nine spontaneously breathing anesthetized supine dogs. Airflow was measured with a pneumotachograph mounted on an airtight muzzle placed over the nose and mouth of each animal. Upper airway pressure was measured as the differential pressure between the extrathoracic trachea and the inside of the muzzle. Upper airway resistance was monitored as an index of airway patency. Negative pressure (-2 to -20 cmH2O) was applied around the neck by using a cuirass extending from the jaw to the thorax. In each animal, increasingly negative pressures were transmitted to the airway wall in a progressive, although not linear, fashion. Decreasing the pressure produced a progressive fall in upper airway resistance, without causing a significant change in respiratory drive or respiratory timing. At -5 cmH2O pressure, there occurred a significant fall in upper airway resistance, comparable with the response of a single, intravenous injection of sodium cyanide (0.5-3.0 mg), a respiratory stimulant that produces substantial increases in respiratory drive. We conclude that upper airway resistance is influenced by the transmural pressure across the airway wall and that such a gradient can be accomplished by making the extraluminal pressure more negative.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Effects of Nasal Pathologies on Obstructive Sleep Apnea

2007 ◽  
Vol 50 (3) ◽  
pp. 167-170 ◽  
Author(s):  
Murat Enoz
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Airway Resistance ◽  
Mouth Opening ◽  
Upper Airway ◽  
Upper Airways ◽  
Oral Breathing ◽  
Pharyngeal Airway ◽  
Obstructive Sleep ◽  
Upper Airway Muscles

Increased airway resistance can induce snoring and sleep apnea, and nasal obstruction is a common problem in snoring and obstructive sleep apnea (OSA) patients. Many snoring and OSA patients breathe via the mouth during sleep. Mouth breathing may contribute to increased collapsibility of the upper airways due to decreased contractile efficiency of the upper airway muscles as a result of mouth opening. Increased nasal airway resistance produces turbulent flow in the nasal cavity, induces oral breathing, promotes oscillation of the pharyngeal airway and can cause snoring.

The evaluation of physiologic decannulation readiness according to upper airway resistance measurement

2008 ◽  
Vol 139 (4) ◽  
pp. 535-540 ◽  
Author(s):  
Chunli Gao ◽  
Liang Zhou ◽  
Chunsheng Wei ◽  
Matthew R. Hoffman ◽  
Cai Li ◽  
...  
Keyword(s):  
Airway Resistance ◽  
Operating Characteristic ◽  
Upper Airway ◽  
High Sensitivity ◽  
Deep Breathing ◽  
Clinical Criteria ◽  
Receiver Operating Characteristic Curves ◽  
Upper Airway Resistance ◽  
Laryngeal Disease ◽  
Subglottal Pressure

Objective To measure the upper-airway resistance in patients with tracheostomies and determine the value representing decannulation readiness. Subjects and Methods Fifty-six patients with tracheostomies resultant to laryngeal disease participated in this study. Forty patients met clinical criteria for decannulation; 16 did not. Subglottal pressure was measured with a tube connected to the tracheostomy tube, and airflow was monitored simultaneously using a facemask. Upper-airway resistance measurements were recorded during shallow and deep breathing. Results During both shallow and deep breathing, the inspiratory and expiratory resistances were significantly higher for the group unsuitable for decannulation ( P < .0001). The areas under the receiver operating characteristic curves were 0.938 or greater for the four curves, indicating a high sensitivity and specificity of resistance measures for diagnosis. Conclusions Objective measurement of upper-airway resistance during shallow and deep breathing may be a useful parameter in determining decannulation readiness of tracheostomized patients.

391 Upper Airway Resistance Syndrome is associated with high Cyclic Alternating Pattern

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A155-A156
Author(s):  
Luciana Godoy ◽  
Letícia Soster ◽  
Clarissa Bueno ◽  
Sonia Togeiro ◽  
Dalva Poyares ◽  
...  
Keyword(s):  
Airway Resistance ◽  
Upper Airway ◽  
Sleep Fragmentation ◽  
Control Group ◽  
Flow Limitation ◽  
Upper Airway Resistance Syndrome ◽  
Arousal Index ◽  
Upper Airway Resistance ◽  
Cyclic Alternating Pattern ◽  
Cap Rate

Abstract Introduction Upper Airway Resistance Syndrome (UARS) is suspected in individuals with excessive daytime sleepiness, fatigue, and sleep fragmentation associated with increased respiratory effort. UARS can negatively impact daytime function. Conventional polysomnography parameters do not demonstrate significant abnormalities in UARS patients but increase in RERAs and arousal index. Cyclic alternating pattern (CAP) is a periodic electroencephalogram activity of non-REM sleep that expresses a condition of sleep instability. The objective of the study was to compare CAP components between UARS patients and health individuals. Methods Fifteen subjects with UARS and 15 age- and sex- matched controls had their sleep study blinded analyzed. UARS criteria were the presence of sleepiness (Epworth Sleepiness Scale – ESS - ≥ 10) and/or fatigue (Modified Fatigue Impact Scale ≥ 38) associated with an apnea/hypopnea index (AHI) ≤ 5 and a respiratory disturbance index (RDI) &gt; 5 events/hour of sleep, and/or flow limitation in more than 30% of total sleep time. Control group criteria were AHI &lt; 5 events/hour, RDI ≤ 5 events/hour and &lt; 30% of TST with flow limitation and ESS &lt; 10, without sleep, clinical, neurological, or psychiatric disorder. CAP electroencephalogram of both groups was analyzed. Results We found higher CAP rate (p = 0.05) and CAP index in N1 stage (p &lt; 0.001) and in N3 stage (p &lt; 0.001) in UARS patients compared to control group. Considering only CAP phase A1 analysis, UARS patients presented higher CAP rate (p = 0.05) and CAP index in N1 stage (p &lt; 0.001) as well as CAP index in N3 stage (p &lt; 0.001) compared to control group. Considering only CAP phase A2 analysis, UARS patients also presented higher number of CAP in N1 stage (p = 0.05). There was no significant difference for CAP phase A3 between groups. Conclusion Although UARS is associated with high arousal index, we found increase in CAP phase A1 and A2, which do not include necessarily AASM arousals, suggesting not only sleep fragmentation but also sleep instability. Support (if any) Associação Fundo de Incentivo à Pesquisa (AFIP) and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).

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