Laryngeal and Tracheal Pressure Injuries in Patients With COVID-19—Reply

Sprague–Dawley female rats were immunized with egg albumin (EA) in aluminum hydroxide gel (AHG) and with or without Bacillus pertussis vaccine (BPV). Fourteen days later, the animals were anesthetized and challenged with EA intravenously. The resultant increase in tracheal pressure was recorded as an index of anaphylactic bronchoconstriction. Ventilation with tracheal pressures of 6 cm H2O (588 N/m2) allowed maximal development of bronchoconstrictor responses to specific antigen challenge that were similar in both pithed and pentobarbital-anesthetized preparations. Forced reinflation of the lungs did not affect the magnitude of the response but did facilitate its recovery. Serum titers evaluated by 3-h and 72-h passive cutaneous anaphylactic reactions indicated that reaginic antibodies were primarily involved, although other immunoglobulins may have played a contributory role. Antigen dose-responses were similar for both the EA-AHG and EA-AHG-BPV immunized groups of animals despite lower reaginic serum titers for the former group. Thus, an immediate-type bronchial anaphylactic response mediated primarily by reaginic antibodies can be elicited in rats and quantitatively assessed. The potential immunologic similarity of these animals to human allergic asthma suggests their utility for further investigation.

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TRH-containing neurons in the nucleus ambiguus regulate tracheal pressure

Neuroscience Research Supplements ◽

10.1016/s0921-8696(06)80240-9 ◽

1991 ◽

Vol 14 ◽

pp. S84

Author(s):

Michiko Iwase ◽

Masato Sibuya ◽

Arata Kanamaru ◽

Ikuo Homma ◽

Seiji Shioda ◽

...

Keyword(s):

Nucleus Ambiguus ◽

Tracheal Pressure

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Respiratory Mechanics of Sound Production in Chickens and Geese

Journal of Experimental Biology ◽

10.1242/jeb.72.1.229 ◽

1978 ◽

Vol 72 (1) ◽

pp. 229-250

Author(s):

J. H. BRACKENBURY

Keyword(s):

Respiratory System ◽

Simultaneous Measurement ◽

Sound Production ◽

High Pressures ◽

Respiratory Mechanics ◽

Air Flow ◽

Tracheal Pressure ◽

Wide Range ◽

Range Of Values ◽

Respiratory Movements

1. Air flow, air sac pressure and tracheal pressure were measured in chickens and geese during a variety of different vocal and non-vocal activities. 2. Air flow and air sac pressure may rise to 500 ml s−1 and 60 cmH2O (6 103 N/m2) respectively during a crow in the chicken. During a sequence of honks in the goose the corresponding values are 650 ml s−1 and 25 cmH2O(2.5 × 10 3 N/m2) respectively. 3. The volume of air delivered through the respiratory system during a single crow is more than 400 ml, almost equivalent to the total volume of the lung air sac system. 4. The efficiency of the chicken syrinx as a sound producing instrument, estimated by comparing the sound energy radiated with the energy consumed in the expulsion of air during a crow, appears to be less than 2 %. 5. Cutting the paired sternotrachealis muscles had no effect on vocalization. 6. The measured rates of clucking, cheeping and honking in adult chickens, young chicks and adult geese respectively are comparable to the characteristic rates of panting in these animals. This points to a similarity in the nature of the respiratory movements involved in each case. 7. Simultaneous measurement of tracheal flow and pressure indicate that the glottis is capable of controlling air flow over a wide range of values in the presence of high pressures. During defaecation the valve is closed whilst during coughing it is wide open.

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Servo respirator constructed from a positive-pressure ventilator

Journal of Applied Physiology ◽

10.1152/jappl.1976.41.2.252 ◽

1976 ◽

Vol 41 (2) ◽

pp. 252-255 ◽

Cited By ~ 24

Author(s):

J. E. Remmers ◽

H. Gautier

Keyword(s):

Negative Feedback ◽

Differential Amplifier ◽

Positive Pressure ◽

Precise Control ◽

Pressure Signal ◽

Response Characteristics ◽

Tracheal Pressure ◽

Selection Of

We have constructed an electronically controlled respirator from three commercially available components: a positive-pressure ventilator, a recorder pen motor, and a differential amplifier. Using negative feedback derived from a tracheal pressure signal, the instrument functions as a servo respirator which provides precise control of tracheal pressure. The system's power and response characteristics are well suited for ventilation of anesthetized cats and dogs. The servo respirator can be used as an externallycontrolled respiratory pump which provides flexibility in selection of the parameters of the ventilatory cycle. Alternatively, it can function as a “demand” respirator which generates transthoracic pressure proportional to efferent respiratory discharge.

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Modified method for bronchial suture by Ramirez Gama compared to separate stitches suture: experimental study

Revista do Colégio Brasileiro de Cirurgiões ◽

10.1590/s0100-69912014000300009 ◽

2014 ◽

Vol 41 (3) ◽

pp. 188-192

Author(s):

Vitor Mayer de Moura ◽

Erinaldo Rocha Paes Lamdim ◽

Felipe Souza Ferraz ◽

Rodrigo Carvalho Turatti ◽

Carolina de Barros Jaqueta ◽

...

Keyword(s):

Experimental Study ◽

The Other ◽

Compressed Air ◽

Air Leak ◽

Bronchial Stump ◽

Modified Method ◽

Tracheal Pressure ◽

Air Ventilation ◽

Manual Suture ◽

Isolated Trachea

OBJECTIVE: To experimentally compare two classic techniques described for manual suture of the bronchial stump. METHODS: We used organs of pigs, with isolated trachea and lungs, preserved by refrigeration. We dissected 30 bronchi, which were divided into three groups of ten bronchi each, of 3mm, 5mm, and 7mm, respectively. In each, we performed the suture with simple, separated, extramucosal stitches in five other bronchi, and the technique proposed by Ramirez and modified by Santos et al in the other five. Once the sutures were finished, the anastomoses were tested using compressed air ventilation, applying an endotracheal pressure of 20mmHg. RESULTS: the Ramirez Gama suture was more effective in the bronchi of 3, 5 and 7 mm, and there was no air leak even after subjecting them to a tracheal pressure of 20mmHg. The simple interrupted sutures were less effective, with extravasation in six of the 15 tested bronchi, especially in the angles of the sutures. These figures were not significant (p = 0.08). CONCLUSION: manual sutures of the bronchial stumps were more effective when the modified Ramirez Gama suture was used in the caliber bronchi arms when tested with increased endotracheal pressure.

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Mass loading of the upper airway extraluminal tissue space in rabbits: effects on tissue pressure and pharyngeal airway lumen geometry

Journal of Applied Physiology ◽

10.1152/japplphysiol.91236.2008 ◽

2009 ◽

Vol 106 (3) ◽

pp. 887-892 ◽

Cited By ~ 27

Author(s):

Kristina Kairaitis ◽

Lauren Howitt ◽

John R. Wheatley ◽

Terence C. Amis

Keyword(s):

Pressure Transducer ◽

Tissue Expander ◽

Upper Airway ◽

Fat Pad ◽

Pharyngeal Wall ◽

Airway Patency ◽

Pharyngeal Airway ◽

Obstructive Sleep ◽

Tracheal Pressure ◽

Tissue Space

Lateral pharyngeal fat pad compression of the upper airway (UA) wall is thought to influence UA size in patients with obstructive sleep apnea. We examined interactions between acute mass/volume loading of the UA extra-luminal tissue space and UA patency. We studied 12 supine, anesthetized, spontaneously breathing, head position-controlled (50°), New Zealand White rabbits. Submucosal extraluminal tissue pressures (ETP) in the anterolateral (ETPlat) and anterior (ETPant) pharyngeal wall were monitored with surgically inserted pressure transducer-tipped catheters (Millar). Tracheal pressure (Ptr) and airflow (V̇) were measured via a pneumotachograph and pressure transducer inserted in series into the intact trachea, with hypopharyngeal cross-sectional area (CSA) measured via computed tomography, while graded saline inflation (0–1.5ml) of a compliant tissue expander balloon in the anterolateral subcutaneous tissue was performed. Inspiratory UA resistance (Rua) at 20 ml/s was calculated from a power function fitted to Ptr vs. V̇ data. Graded expansion of the anterolateral balloon increased ETPlat from 2.3 ± 0.5 cmH2O ( n = 11, mean ± SEM) to 5.0 ± 1.1 cmH2O at 1.5-ml inflation ( P < 0.05; ANOVA). However, ETPant was unchanged from 0.5 ± 0.5 cmH2O ( n = 9; P = 0.17). Concurrently, Rua increased to 119 ± 4.2% of baseline value ( n = 12; P < 0.001) associated with a significant reduction in CSA between 10 and 70% of airway length to a minimum of 82.2 ± 4.4% of baseline CSA at 40% of airway length ( P < 0.05). We conclude that anterolateral loading of the upper airway extraluminal tissue space decreases upper airway patency via an increase in ETPlat, but not ETPant. Lateral pharyngeal fat pad size may influence UA patency via increased tissue volume and pressure causing UA wall compression.

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GABAergic Pump Cells of Solitary Tract Nucleus Innervate Retrotrapezoid Nucleus Chemoreceptors

Journal of Neurophysiology ◽

10.1152/jn.00322.2007 ◽

2007 ◽

Vol 98 (1) ◽

pp. 374-381 ◽

Cited By ~ 32

Author(s):

Ana C. Takakura ◽

Thiago S. Moreira ◽

Gavin H. West ◽

Justin M. Gwilt ◽

Eduardo Colombari ◽

...

Keyword(s):

Area Postrema ◽

Inhibitory Neurons ◽

Acid Decarboxylase ◽

Solitary Tract ◽

Vagus Nerves ◽

Toxin B ◽

Lung Inflation ◽

Retrotrapezoid Nucleus ◽

Nucleus Of Solitary Tract ◽

Tracheal Pressure

The retrotrapezoid nucleus (RTN) contains central respiratory chemoreceptors that are inhibited by activation of slowly adapting pulmonary stretch receptors (SARs). Here we examine whether RTN inhibition by lung inflation could be mediated by a direct projection from SAR second-order neurons (pump cells). Pump cells ( n = 56 neurons, 13 rats) were recorded in the nucleus of solitary tract (NTS) of halothane-anesthetized rats with intact vagus nerves. Pump cells had discharges that coincided with lung inflation as monitored by the tracheal pressure. Their activity increased when end-expiratory pressure was raised and stopped instantly when ventilation was interrupted in expiration. Many pump cells could be antidromically activated from RTN (12/36). Nine of those were labeled with biotinamide. Of these nine cells, eight contained glutamic acid decarboxylase 67 (GAD67) mRNA and seven were found to reside in the lower half of the interstitial subnucleus of NTS (iNTS). Using the retrograde tracer cholera toxin-B, we confirmed that neurons located in or close to iNTS innervate RTN (two rats). Many such neurons contained GAD67 mRNA and a few contained glycine transporter2 (GLYT2) mRNA. Anterograde tract tracing with biotinylated dextranamide (four rats) applied to iNTS also confirmed that this region innervates RTN by a predominantly GABAergic projection. This work confirms that many rat NTS pump cells are located in and around the interstitial subnucleus at area postrema level. We demonstrate that a GABAergic subset of these pump cells innervates the RTN region. We conclude that these inhibitory neurons probably contact RTN chemoreceptors and mediate their inhibition by lung inflation.

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