We tested that the breath-by-breath V(O2) determination by an algorithm termed BR did not bias the kinetics parameters. It was compared to two other algorithms using a correction for changes in lung gas stores between two successive breaths (AU, W) and one without correction (NC). Ten healthy male subjects cycled ...

Upper airway unidirectional breathing, nose in and mouth out, is used by panting dogs to facilitate heat removal via water evaporation from the respiratory system. Why some humans instinctively employ the same breathing pattern during respiratory distress is still open to question. We hypothesized that 1) humans unconsciously perform unidirectional ...

Oxygen is the commonest drug prescribed in hospitals. The inhaled concentration is altered by the administered oxygen flow rate, the characteristics of the delivery device and the patient's respiratory pattern. Using healthy volunteers we measured the inspired oxygen concentration achieved with different devices both at rest and when the breathing ...

BACKGROUND AND OBJECTIVE: Nasal breathing provides a protective influence against exercise-induced asthma. We hypothesized that enforced oral breathing in resting mild asthmatic subjects may lead to a reduction in lung function. METHODS: Asymptomatic resting mild asthmatic volunteers (n = 8) were instructed to breathe either nasally only (N; tape over ...

BACKGROUND AND AIM: Previous studies have shown that while performing the (14)C-urea breath test ((14)C-UBT) for the detection of Helicobacter pylori (H. pylori), there is possibility of false-positive results due to the other urease producing bacteria present in oropharynx, if breath samples are obtained within 30 min after administration of ...

As a simple, non-invasive method of blood oxygenation level-dependent (BOLD) signal calibration, the breath-hold task offers considerable potential for the quantification of neuronal activity from functional magnetic resonance imaging (fMRI) measurements. With an aim to improve the precision of this calibration method, the impact of respiratory rate control on the ...

OBJECTIVES: To measure the extent of dilution of helium-oxygen (heliox) by room air when given via high concentration reservoir mask to spontaneously breathing subjects. Substantial dilution of heliox by room air under these circumstances might alter its physical properties sufficiently to negate any potential clinical benefit in obstructive respiratory failure. ...

BACKGROUND: Despite its importance, total body water (TBW) is usually estimated rather than measured due to the complexity of isotope dilution methods. The aim of this study was to demonstrate the applicability in haemodialysis (HD) patients of a recently developed on-line breath test, previously validated in healthy subjects, that uses ...

The novelty of this study was to investigate the changes in cardiorespiratory and metabolic intensity brought about by the practice of pranayamas (breathing exercises of yoga) and meditation during the same hatha-yoga session. The technique applied was the one advocated by the hatha-yoga system. Nine yoga instructors-five females and four ...

Pranayama (breathing exercise), one of the yogic techniques can produce different physiological responses in healthy individuals. The responses of Alternate Nostril Breathing (ANB) the Nadisudhi Pranayama on some cardio-respiratory functions were investigated in healthy young adults. The subjects performed ANB exercise (15 minutes everyday in the morning) for four weeks. ...

INTRODUCTION: Daily change of breathing circuits in the operating theatre requires a lot of resources and is time and labour consuming. The extended use of breathing circuits could reduce the workload of the staff and health care costs. The aim of the present study was to evaluate the contamination rate ...

BACKGROUND: The combined measurement of diffusing capacity of the lung for nitric oxide (Dlno) and diffusing capacity of the lung for carbon monoxide (Dlco) is a simple, noninvasive tool, but methodologic factors might influence results and reproducibility. We thus quantified the influence of breath-hold time on Dlco and Dlno in ...

The use of exhaled breath condensate (EBC) as a tool for noninvasive assessment of lung inflammation is becoming commonplace. Many authors use commercial ELISA kits to measure inflammatory mediators within EBC. However, the very low concentrations of mediators within EBC are often below the commercially validated concentration range of the ...

Optimal collection and analysis of exhaled breath condensate (EBC) are prerequisites for standardisation and reproducibility of assessments. The present study aimed to assess reproducibility of EBC volume, hydrogen peroxide (H(2)O(2)), 8-isoprostane and cytokine measurements using different condensers, including a newly developed glass condenser. At four points in time, 30 healthy ...

We examined whether acetazolamide (ACZ), a carbonic anhydrase inhibitor, would alter post-hypoxic ventilatory behavior and periodic breathing in the C57BL/6J (B6) mouse. Experiments were performed with unanaesthetized, awake adult male B6 mice (n = 5, 2.5 months old, 21.3 +/- 1.5 g, mean +/- SD) and ventilatory behavior was measured ...

The resonant characteristic of heart rate variability is usually generated using biofeedback and the external pacing of breathing, which is typically around 6 breaths/min (0.1 Hz), although the exact frequency varies between individuals. It was hypothesized that the actual resonant characteristic of heart rate actually depends on the current psychophysiological ...

It has been shown that teachers are at high risk of developing occupational dysphonia, and it has been widely accepted that the vocal characteristics of a speaker play an important role in determining the reactions of listeners. The functions of breathing, breathing movement, breathing tonus, voice vibrations and articulation tonus ...

Paralysis of the respiratory muscles in people with tetraplegia affects their ability to breathe and contributes to respiratory complications. Surface functional electrical stimulation (FES) of abdominal wall muscles can be used to increase tidal volume (V_{T}) and improve cough peak flow (CPF) in tetraplegic subjects who are able to breathe ...

BACKGROUND: The image quality of 4DCT depends on breathing regularity. Respiratory audio coaching may improve regularity and reduce motion artefacts. We question the safety of coached planning 4DCT without coaching during treatment. We investigated the possibility of coaching to a more stable breathing without changing the breathing amplitude. The interfraction ...

BACKGROUND: Vigorous outdoors exercise during an episode of air pollution might cause airway inflammation. The purpose of this study was to examine the effects of vigorous outdoor exercise during peak smog season on breath pH, a biomarker of airway inflammation, in adolescent athletes. METHODS: We measured breath pH both pre- ...

In this study, we examine the effect of exercise on the time and flow characteristics of the respiratory cycle profile at the point of volitional exercise termination. Eight males (mean age 29 years, s = 10; body mass 74 kg, s = 7; height 1.75 m, s = 0.04) undertook ...

We tested the hypothesis that the pattern of chest wall configuration during speech production correlates with the pattern of chest wall motion during resting breathing. Twenty-one men (age 40 +/- 8 years) with ankylosing spondylitis and varied degrees of ribcage involvement participated in the study. None of the patients had ...

During high respiratory drive competition between the need for oxygen and the needs of speech breathing are in conflict. This conflict provides a way of exploring linguistic structure in two domains. Syntactically, talkers must breath more frequently such that inhalations occur within sentences, a rarity in Collins 1979, Doust & ...

Because fasting king penguins (Aptenodytes patagonicus) need to conserve energy, it is possible that they exhibit particularly low metabolic rates during periods of rest. We investigated the behavioral and physiological aspects of periods of minimum metabolic rate in king penguins under different circumstances. Heart rate (f(H)) measurements were recorded to ...

The mismatch negativity (MMN) paradigm that is an indicator of preattentive processing was used to study the effects of concentrative meditation. Sudarshan Kriya Yoga meditation is a yogic exercise practiced in an ordered sequence beginning with breathing exercises, and ending with concentrative (Sahaj Samadhi) meditation. Auditory MMN waveforms were recorded ...

Previous studies have shown that exposure to chronic hypoxia (CH) and chronic hypercapnia (CHC) alone have opposite effects on central respiratory-related pH/CO(2) chemosensitivity in the cane toad (Bufo marinus). This study examined the effects of chronic hypoxic hypercapnia (CHH) on central pH/CO(2) chemosensitivity. Cane toads were maintained at 10% O(2) ...

OBJECTIVE: Many patients with functional dyspepsia (FD) have postprandial symptoms, impaired gastric accommodation and low vagal tone. The aim of this study was to improve vagal tone, and thereby also drinking capacity, intragastric volume and quality of life, using breathing exercises with vagal biofeedback. MATERIAL AND METHODS: Forty FD patients ...

The main technological problem associated with measuring gas exchange in submerged divers breathing from a self-contained underwater breathing apparatus (SCUBA) involves simulating ambient water pressure on the expired side of the SCUBA regulator without causing regulator free-flow. This report presents a method to acquire expired gas from exercising divers for ...

The effect of the self-contained breathing apparatus (SCBA) with compressed air (BA-A) on ventilatory mechanics, work of breathing (WOB), pulmonary function, and respiratory muscle fatigue, was compared with that of a low resistance breathing valve (LRV). Further, the effect of unloading the respiratory muscles with heliox with the SCBA (BA-H) ...

INTRODUCTION: Bystander cardiopulmonary resuscitation (CPR) has been shown to significantly improve outcome in sudden cardiac arrest in children. In view of this, most emergency medicine services deliver telephone instructions for carrying out CPR to laypeople who call the emergency services. Little is known as to whether laypeople carrying out these ...

INTRODUCTION: When investigating apnea, for example in diving or altitude studies, hypoxemia is a variable that must be monitored to reduce the risk of hypoxic syncope. Pulse oximetry is a simple technique that measures arterial oxygen saturation (SpO2). As apnea induces a peripheral vasoconstriction, we hypothesized that it would be ...

Pacific tarpon (Megalops cyprinoides) use a modified gas bladder as an air-breathing organ (ABO). We examined changes in cardiac output (V(b)) associated with increases in air-breathing that accompany exercise and aquatic hypoxia. Juvenile (0.49 kg) and adult (1.21 kg) tarpon were allowed to recover in a swim flume at 27 ...

This communication describes the application of the barometric technique to the measurements of the breathing pattern (tidal volume and breathing rate) and pulmonary ventilation (VE) in chicken embryos and hatchlings. The chamber-plethysmograph was separated into two sections, an animal compartment, maintained at incubation temperature, and a recording compartment kept at ...

PURPOSE: Breathing pattern retraining is frequently used for exertional dyspnea relief in adults with moderate to severe chronic obstructive pulmonary disease. However, there is contradictory evidence to support its use. The study objective was to compare 2 programs of prolonging expiratory time (pursed-lips breathing and expiratory muscle training) on dyspnea ...

Normal subjects terminate breath-holds due to intolerable 'air hunger'. We hypothesize that competitive breath-hold divers might have increased tolerance of air hunger. We tested the air hunger (AH) response of four divers who could hold their breath for 6-9 min. Tidal volume and respiratory rate were controlled by mechanical ventilation ...

PURPOSE: We evaluated the influence of prior maximal exhalation on preoxygenation in 15 adult volunteers using tidal volume breathing (TVB) for five minutes and deep breathing (DB) for two minutes with and without prior maximal exhalation. METHODS: Inspired and end-tidal oxygen, nitrogen and carbon dioxide were monitored continuously and recorded ...

A practical method of breath-by-breath monitoring of metabolic gas exchange has been developed by GE Healthcare/Datex Ohmeda and incorporated into existing anaesthetic and critical care monitoring systems (M-COVXO). This device relates flow measurements made at the mouth by pneumotachograph to measurements of inspired and expired gas composition by matching the ...

Stressed and tense individuals often are recommended to change the way they breathe. However, psychophysiological effects of breathing instructions on respiration are rarely measured. We tested the immediate effects of short and simple breathing instructions in 13 people seeking treatment for panic disorder, 15 people complaining of daily tension, and ...

We tested the hypothesis that breathing through an inspiratory threshold device (ITD) during progressive central hypovolemia would protect cerebral perfusion and attenuate the reporting of presyncopal symptoms. Eight human subjects were exposed to lower-body negative pressure (LBNP) until the presence of symptoms while breathing through either an active ITD (-7 ...

A variety of experimental approaches in human subjects and animal models established that the vestibular system contributes to regulation of respiration. In cats, the surgical elimination of labyrinthine signals produced changes in the spontaneous activity and posturally related responses of a number of respiratory muscles. However, these effects were complex ...

The healthy respiratory system has a remarkable capacity for meeting the metabolic demands placed upon it during strenuous exercise. For example, in order to regulate alveolar partial pressure of oxygen and carbon dioxide during heavy workloads, a 20-fold increase in alveolar ventilation can occur. The high metabolic costs and subsequent ...

BACKGROUND: Recent work has demonstrated that among irritable bowel syndrome (IBS) subjects, methane on lactulose breath test (LBT) is nearly universally associated with constipation predominance. This work has been based on subjective constipation outcomes. In this study, methane is compared to constipation in another population of IBS subjects with constipation ...

The Pacific tarpon is an elopomorph teleost fish with an air-breathing organ (ABO) derived from a physostomous gas bladder. Oxygen partial pressure (PO(2)) in the ABO was measured on juveniles (238 g) with fiber-optic sensors during exposure to selected aquatic PO(2) and swimming speeds. At slow speed (0.65 BL s(-1)), ...

The purpose of this study was to examine the effects of orally ingested sodium bicarbonate (NaHCO3) on voluntary breath-hold time with facial immersion. Eight non-elite breath-hold divers aged 20-41 (26.75 +/- 7.83 years) were recruited to undertake two bouts of three monitored, facial-immersion breath-holds, one week apart. Subjects were randomly ...

In helium saturated rat abdominal adipose tissue, helium bubbles were studied at 101.3 kPa during breathing of either heliox(80:20), 100% oxygen or air after decompression from an exposure to heliox at 405 kPa for one hour. While breathing heliox bubbles initially grew for 15-115 minutes then shrank slowly; three out ...

BACKGROUND: Nitric oxide has become a vital indicator of health since many cells produce it constitutively. It is present in exhaled breath and can be measured. MATERIAL/METHODS: A Kiernan NO Breath analyzer (KNB) was used in the present study to determine nitric oxide (NO) levels in exhaled human breath. The ...

Continuous Positive Airway Pressure (CPAP) is a commonly accepted method of spontaneous breathing support in obstructive lung disease. Previous work suggested that the cause of the CPAP efficacy in the obstructive lung disease localized in bronchi of middle order (OLDMO) is not as obvious as, for example, in the obstructive ...

We assessed cutaneous ethanol (ETOH) and isopropanol (ISOP) absorption after intensive (30 times per h) use of alcohol-based hand-rub solutions by healthcare workers (HCWs). ETOH was detectable in the breath of 6/20 HCWs (0.001 to 0.0025%) at 1 to 2 min postexposure and in the serum of 2/20 HCWs at ...

The purpose of this study was to develop an efficient method of determining gate-on and -off timing in respiration-gated radiotherapy. Gate-on and -off timing in a breathing cycle were defined as the respiratory signal level for the start of irradiation (Ls) in the expiration phase and that for the end ...

AIM: To determine whether a shortened (13)C urea breath test ((13)C UBT) (breath collection time of 10 min) is as reliable as the standard assay (30 min). METHODS: Two hundred ninety-seven patients (mean +/- SD: 53+/-16 years, 57% female) completed a (13)C UBT. Breath samples were obtained at baseline and ...