In previous studies the possibility of a mechanism of hemodynamic imbalance consequent to a sharp decrease in blood pressure causing a more or less transient inner ear impairment was evaluated and to some extent demonstrated. In this scenario, tinnitus is very frequently present as a debilitating symptom associated to cochlear ...

Endotracheal suctioning is performed regularly in ventilated infants and children to remove obstructive secretions. The effect of suctioning on respiratory mechanics is not known. This study aimed to determine the immediate effect of endotracheal suctioning on dynamic lung compliance, tidal volume, and airway resistance in mechanically-ventilated paediatric patients by means ...

Oto-acoustic emissions (OAEs) are low intensity sounds which can be recorded in the external ear canal with a sensitive microphone. They are initiated by the activated motility of the outer hair cells which provide mechanical feedback (the cochlear amplifier) to the basilar membrane, enhancing its displacement. Therefore it has been ...

The tracheal tube cuff performs an important function during anesthesia and critical care situations by allowing positive pressure ventilation and isolating the lungs from aspiration. Other maneuvers, such as pressure support ventilation and positive end-expiratory pressure, are also cuff-dependent. However, excessive cuff pressure, as well as long-term intubation without excessive ...

BACKGROUND: The problem of eliminating gastroesophageal reflux (GER) with simple, effective and devoid of unpleasant side effects procedures is still unresolved. We tried to settle this problem with a magnetic device that should be applied to the distal end of the esophagus. MATERIALS AND METHODS: Two plastoferrite magnets of 2 ...

OBJECTIVES: With the knowledge of differences in anatomic structures between the trachea and the esophagus, the authors conducted an animal study to evaluate the usefulness of endotracheal cuff pressure in distinguishing endotracheal and esophageal intubations. METHODS: Six swine were anesthetized and endotracheally intubated with 7.5-mm cuffed endotracheal tubes. The intubations ...

We show that arc menisci configuration under primary drainage in capillary tube cross sections and, by extension, in throats in the void structure of rock and soil, can be understood in terms of the computational geometry theory of medial axis analysis. The solution for arc meniscus configuration is developed for ...

Cuffed tracheal tubes are becoming increasingly popular in paediatric anaesthesia and intensive care medicine. To avoid cuff related complications and airway morbidity, a thorough understanding of cuff volume/pressure behaviour and management is required. In this study, the outer cuff diameter and form stability of the cuff at high cuff pressure ...

INTRODUCTION: The aim of this study was to evaluate the effect of pressure-equalizing earplugs available in major airports and drugstores. No previous study has focused on preventing barotrauma using these earplugs. METHODS: Blinded and double-blinded, one type of pressure-equalizing earplugs (JetEars) was studied in 27 volunteers disposed to ear barotrauma. ...

STUDY OBJECTIVE: Excessive pressure exerted on the tracheal mucosa is an avoidable factor implicated as a cause of damage after intubation of the trachea with cuffed tubes. Many patients are intubated in the out-of-hospital setting by emergency medical teams. The time spent in the out-of-hospital setting could very well be ...

The two essential regulating mechanisms of the middle ear pressure are the trans-mucosal gas exchange in the middle ear and the ventilation function of the eustachian tube (ET). The physiological mechanism of these both functions is not yet clear. The purpose of this study was to evaluate the role of ...

Earlier theoretical analyses of the rate of propagation of pressure-concentration waves in the phloem were performed without adequate attention to the elastic expansion of sieve tube walls. Here, it is shown that the rate of propagation of pressure-concentration waves in phloem sieve tubes is not significantly impeded by wall elasticity, ...

PURPOSE: To determine, in dogs anesthetized with nitrous oxide (N2O), (whether the endotracheal tube (ETT) cuffed with a Lanz pressure regulating valve decreases the tracheal consequences of tracheal intubation. METHODS: Sixteen mixed-breed dogs were allocated to two groups according to the ETT used: Control group (n = 8) - Rüsch ...

INTRODUCTION: Early detection of an inadvertent esophageal intubation can be particularly challenging in cases when the current standard of care, carbon dioxide detection, is unreliable. We sought to determine the sensitivity and specificity of an inexpensive and portable device, the gum elastic bougie (Eschmann Tracheal Tube Introducer, SIMS Portex, Inc, ...

Inappropriate cuff filling is responsible for various complications related to the use of an endotracheal tube (ETT). In this study, we evaluated an objective, noninvasive method for continuous assessment of leak around the ETT cuff by monitoring carbon dioxide pressure (P(CO2) in the upper airway. P(CO2) levels were measured by ...

Pressure fields in rigid smooth straight tubes with an axially uniform cross section, in which an incompressible Newtonian fluid flows steadily, have been determined. Five cross section shapes are used. The reference cross section S0 is slightly elliptic (ellipticity of 1.005). Four cross section shapes, which mimic collapsed vessels in ...

OBJECTIVE: This study was designed to quantitatively assess the contribution of various factors to the conductive hearing loss in otitis media. BACKGROUND: In the conductive hearing loss seen in cases of serous otitis media, various volumes of fluid of different viscosities along with subatmospheric (negative) pressure are found in the ...

BACKGROUND: The aim of this study was to evaluate the performance of a new cuff pressure release valve (CPRV), in which the release pressure can be adjusted from 10 to 25 cmH2O, particularly intended to control pressure in paediatric cuffed tracheal tubes and to avoid cuff hyperinflation caused by N2O ...

A three-dimensional (3D) finite element (FE) model of human ear with accurate structural geometry of the external ear canal, tympanic membrane (TM), ossicles, middle ear suspensory ligaments, and middle ear cavity has been recently reported by our group. In present study, this 3D FE model was modified to include acoustic-structural ...

OBJECTIVE: Submarine escape training is carried out by preselected, healthy young men under strictly controlled conditions regarding exposure to pressure and the rate of pressure change. This provides a unique opportunity to investigate the relations between middle ear characteristics and susceptibility to barotrauma while avoiding possible confounding parameters. We examined ...

CONCLUSION: The results of this study give support to the theory that opening the middle ear (ME) to the atmosphere leads to a deterioration in its pressure regulation capacity. However, this is probably not the reason why a perforation of the tympanic membrane becomes chronic. OBJECTIVE: Direct, continuous measurement is ...

Middle ear pathology has a negative effect on the detectability of otoacoustic emissions. In this study, we investigated the effect of compensating a deviant static middle ear pressure while measuring transient evoked otoacoustic emissions (TEOAEs). In 59 children (mean age 4 years, 5 months) TEOAEs were measured twice in one ...

The tracheal mucosa is very a delicate structure, and pressure-ischaemia problems following the use of cuffed tracheostomy tubes are well documented. Iatrogenic tracheal stenosis is one of the consequences of mucosal ischaemia and is very difficult to treat. In this study the accuracy of finger-tip tested tracheostomy tube cuff inflation ...

AIMS: To determine 1) the best position for hydroxylapatite malleus-to-footplate (MFP), ossicular replacement prosthesis (ORP) in reconstructed ears, and 2) whether preserving the stapes superstructure (SS), when present, has acoustic advantages. BACKGROUND: Positioning of the MFP-ORP head beneath the neck of the malleus may produce maximal force, whereas positioning beneath ...

The effect of air pressure change on bone conduction (BC) hearing thresholds in the occluded ear was investigated. The pump manometer system of an impedance bridge was used to change the air pressure in the ear canal of twenty-two normally hearing subjects. BC thresholds were measured with: (1) open ear; ...

CONCLUSIONS: We demonstrated errors introduced by the gas permeability of the tubing and additional dead space. Materials with practically no permeability, such as glass, must be used to overcome the loss or gain of gas through the walls of tubes used for studying ME gas variations. Experiments conducted at a ...

OBJECTIVE: Otoacoustic emissions (OAEs) are widely used for assessing congenital and early-acquired sensorineural hearing loss in young children. Middle ear pathology has a negative effect on the presence of OAEs. In this study we investigated whether measuring OAEs at compensated middle ear pressure (CMEP) resulted in a higher pass rate ...

We investigated the effect of pneumatic pressure applied to the proximal musculature of the sheep foreleg on load at the site of a transverse osteotomy of the distal radius. The distal radii of 10 fresh sheep foreleg specimens were osteotomized and a pressure sensor was inserted between the two bone ...

The trachea is easily accessible at the bedside. As such it provides ready access for emergency airway cannulation (eg, in the setting of acute upper airway obstruction) and for chronic airway access after laryngeal surgery. More commonly, tracheostomy tubes are placed to allow removal of a translaryngeal endotracheal tube. Tracheostomy ...

OBJECTIVE: Self-measurement of blood pressure using an automated home blood pressure monitoring (AHBPM) is increasingly used in hypertension management. Internet commerce increases dramatically each year. This study looked to identify the availability of validity of AHBPM and the correct cuff size to go with the AHBPM. METHODS AND RESULTS: Using ...

OBJECTIVE: Foreign bodies in the ear are mainly encountered in children. This can often pose a problem especially in an accident and emergency department where a microscope or expert help is not routinely available. This paper presents a simple, safe, and effective way of ear syringing. The ease and simplicity ...

Pressure reflectometry is a new and easily applicable technique for simultaneous measurement of cross-sectional area and pressure in a collapsible biological tube. Related values of pressure and cross-sectional area are relevant for assessment of the mechanical properties of a biological tube. A very thin and highly flexible 6 cm long ...

HYPOTHESIS: Modern tympanometers run at higher rates of pressure change than older tympanometers, which increases the inaccuracy of determining the middle ear pressure. BACKGROUND: Tympanometric middle ear pressure may be susceptible to both the direction as well as the rate of pressure change, which is reflected by two different pressure ...

PURPOSE: To compare dynamic autoregulation in the middle cerebral artery (MCA) and the ophthalmic artery (OA) after a step decrease in systemic blood pressure. METHODS: Eighteen healthy male young subjects were studied. Ultrasound parameters and systemic blood pressures were recorded in each subject before, during, and after a step decrease ...

We tested the hypothesis that the life-span of the ProSeal laryngeal mask airway (LMA) is shorter than the Classic LMA. We also compared residual cuff volumes and changes in elastance and permeability with use. Six new size 4 ProSeal LMAs and 6 new size 4 Classic LMAs were tested. Each ...

OBJECTIVE: To investigate the effect of endotracheal tube cuff inflation pressure on the occurrence of liquid aspiration and tracheal wall damage. STUDY DESIGN: Prospective, randomized experimental study. ANIMALS: Ten healthy horses, weighing 535 +/- 55 kg. METHODS: Horses were anesthetized, orotracheally intubated, placed in dorsal recumbency, and maintained on isoflurane ...

HYPOTHESIS: Tympanometric measurements of middle ear pressure in children with secretory otitis media are overestimated in a dose-response manner because of increased hysteresis explained by the viscosity and amount of middle ear fluid. BACKGROUND: Tympanometric middle ear pressure is important in evaluating children with secretory otitis media. These measurements are ...

Patients suffering from Ménière's disease are particularly sensitive to negative pressure in the middle ear. For example, attacks of vertigo can be triggered by a descent in an aircraft when ventilation of the middle ear can become critical. Positive-pressure pulse treatment has been shown to have a beneficial effect on ...

The purpose of this study was to compare the cuff pressures of three tracheostomy tubes, MERA sofit CLEAR, Blue Line Tracheostomy Tube, and Tracheosoft. Each tracheostomy tube with an internal diameter of 7.0 mm was put into a plastic column. The cuff was then inflated with air to seal the ...

BACKGROUND: This study addressed the question of whether barotrauma during colonoscopy is sufficient to rupture the colon. METHODS: A total of 3000 colonoscopies were retrospectively analyzed, and the colonoscopes used for these procedures were evaluated in an in vitro analysis. Air pressure at the tip of the colonoscopes and air ...

Middle ear barotrauma during flight is a painful disorder experienced by passengers who cannot properly regulate their middle ear pressure in response to the changing cabin pressures during ascent and descent. Previous reports emphasized the important role of poor eustachian tube function in disease pathogenesis but paid little attention to ...

The resistance for fluid flow of the cochlear aqueduct was measured in guinea pigs for different positions of the round window membrane. These different positions were obtained by applying different constant pressures to the middle ear cavity. Fluid flow through the aqueduct was induced by small pressure steps superimposed on ...

PURPOSE: To compare cuff pressures during nitrous oxide exposure in the new Microcuff pediatric tracheal tube (MPT) with ultrathin high volume - low pressure polyurethane cuff to a tube with a standard polyvinyl chloride (PVC) cuff. METHODS: With approval of the local Ethics Committee, 30 pediatric patients requiring tracheal intubation ...

During anaesthesia for elective procedures, 2 dogs developed acute airway obstruction caused by herniation of the endotracheal cuff. This is an uncommon but potentially fatal complication especially when minimal monitoring of the patient leads to late recognition of the condition. The most typical symptoms are decreased thoracic excursions and tidal ...

The synchronization of cardiac and locomotor rhythms has been suggested to enhance the efficiency of arterial delivery to active muscles during rhythmic exercise, but direct evidence showing such a functional role has not been provided. In this study, we tested the hypothesis that the heartbeat is coupled with intramuscular pressure ...

We studied the use of an inline syringe as a pressure relief valve for tracheal tube cuffs during exposure to nitrous oxide to see if the technique works. Bench testing was done to determine the stick and slip characteristics of syringes of different brands and sizes. Cuffs were inflated with ...

We examined the amount of thigh tourniquet pressure that can be reduced from the typical 300 to 350 mm Hg by using a new automated plethysmographic limb occlusion pressure measurement technique. We also examined how much pressure could be reduced by using a wide contoured cuff compared with a standard ...

The middle ear pressure was analyzed in 112 patients with dizziness. In 37 patients with Meniere's disease, the middle ear pressure on the low-pressure side was significantly lower, the middle ear pressure difference (between the high and low sides) was significantly larger, and the maximum compliance on the low-compliance side ...

OBJECTIVE: To question the conception of Eustachian tube (ET) dysfunction by investigating some of its passive and active properties. BACKGROUND: Middle ear (ME) fluid accumulation accompanied by a negative pressure is generally accepted to be induced by ET dysfunction, implying that the origin of pathology is within the tube. METHODS: ...

OBJECTIVE: To quantify the incidence and degree of endotracheal tube intraluminal obstruction after mechanical ventilation and its relation to time of intubation. DESIGN: Prospective observational study. SETTING: A 14-bed medical-surgical intensive care unit at a university-affiliated teaching hospital. PATIENTS: Ninety-four endotracheal tubes used in 80 patients requiring mechanical ventilation for ...