In the present study we compared the ventilatory performance whilst wearing self-contained breathing apparatus (SCBA) during exercise, of a group of male fire-fighters (FF, n = 8), with a matched group of male civilians (CV, n = 7). The mean (SEM) physiological characteristics of the subjects (FF vs CV) were: ...

The purposes of this investigation were to quantify the noise component of child breath-by-breath data, investigate the major determinants of the breath-to-breath noise, and to characterise the noise statistically. Twenty-four healthy children (12 males and 12 females) of mean (SD) age 13.1 (0.3) years completed 25 min of steady-state cycle ...

Ventilation and locomotion coupling (entrainment) has been observed and described in rowers during incremental exercise protocols but not during simulated race conditions. The purpose of this descriptive study was to examine ventilation and locomotion entrainment on a breath-by-breath and stroke-by-stroke basis in varsity male rowers during a maximal 2,000-m ergometer ...

The aim of this study was to compare the effects of nasal splinting during different modes of breathing on breathing patterns and cardiorespiratory responses. Ten healthy subjects (4 males, 6 females) performed five maximal treadmill tests while breathing through the nose, nose + dilator, mouth, nose + mouth, and nose ...

Capnometer measurements during 46 evaluable treatments in which patients were administered carbogen (95% O2, 5% CO2) have demonstrated that the mean inspired carbon dioxide level was 3.1% (range 0-4.7) and the mean inspired oxygen concentration was 70.6% (range 26.4-94). The explanation for this observation is leakage of air into the ...

We studied physiological and sensory effects of left cervical vagal stimulation in six adult patients receiving this stimulation as adjunctive therapy for intractable epilepsy. Stimulus strength varied among subjects from 0.1 to 2.1 microCoulomb (microC) per pulse, delivered in trains of 30-45 s at frequencies from 20 to 30 Hz; ...

Multiple factors may contribute to the dyspnea associated with restrictive ventilatory disease (RVD). Simple models that examine specific features of this problem are likely to provide insight into the mechanisms. Previous models of RVD utilizing elastic loads may not represent completely the impact on pulmonary and chest wall receptors derived ...

Pulmonary oedema has been described in swimmers and self-contained underwater breathing apparatus (Scuba) divers. This study reports three cases of haemoptysis secondary to alveolar haemorrhage in breath-hold divers. Contributory factors, such as haemodynamic modifications secondary to immersion, cold exposure, exercise and exposure to an increase in ambient pressure, could explain ...

Minute ventilation (VE, and its pattern) is the result of an interaction between the drive to breathe (from the respiratory controller) and the mechanical properties of the respiratory system. While there is abundant information about the chemoreceptor based control of exercise V E, the present studies were designed to examine ...

Deep breathing and ambulation are used by physiotherapists for patients after surgery, however the precise effects of these on ventilation have not been investigated. This study was designed to compare the effects of deep breathing and ambulation on pattern of breathing in patients after upper abdominal surgery. A similar increase ...

Breathing exercises during immersion in 38 degrees C water were performed in 22 patients with bronchial asthma, pulmonary emphysema and constrictive pulmonary diseases. The patients entered a pool filled with 38 degrees C water to shoulder level. While standing, they breathed in deeply and breathed out slowly through the mouth ...

We have used our selected ion flow tube mass spectrometric method (SIFT-MS) to study isoprene levels in the alveolar breath of 29 healthy volunteers during normal working hours at the varying states of nutrition occurring during this period. Quantification of the breath isoprene was achieved using O(2)(+) precursor ions to ...

The objective of this double-blind clinical study was to investigate the effectiveness of a commercially available dentifrice containing triclosan and a copolymer (Colgate Total Toothpaste) for controlling long-term, i.e., seven-hour and overnight breath odor. In particular, a comparison was made between the level of control of breath odor provided by ...

The effect of deviations from temporal expectations on tempo discrimination was studied in 3 experiments using isochronous auditory sequences. Temporal deviations consisted of advancing or delaying the onset of a comparison pattern relative to an "expected" onset, defined by an extension of the periodicity of a preceding standard pattern. An ...

BACKGROUND AND PURPOSE: Biokinergia (BK) is a massage aimed at improving "biological" potential. An initial pilot study demonstrated that a BK session could alter blood lactate concentration during prolonged exercise. OBJECTIVE: To confirm the effect of BK on performance and physiological adaptations during maximal aerobic muscular exercise. METHODS: Two groups ...

We have compared the performance of a standard T-piece, a Venturi T-piece and a T-bag (T-piece with a small reservoir bag) for emergence with the laryngeal mask airway in 20 awake volunteers. FiO2, ETCO2 and FiCO2 were measured at oxygen flow rates of 2, 4 and 6 l.min-1 during three ...

The influence of the method alveolar air collection on measurements of trace gas concentration has received little attention. We measured the concentrations of H2, CH4, CO, and CO2 in sequential fractions of alveolar air collected with and without breath-holding. Without breath-holding, the concentration of these gases increased appreciably as increasing ...

Little is known about total respiratory resistance (TRR) as a psychophysiological parameter in normal subjects. Therefore, we investigated TRR in 45 healthy students under multiple baseline conditions, isometric arm muscle tension and voluntary deep breathing (VDB). TRR was measured by the forced oscillation technique. In addition, heart rate (HR) as ...

The transthoracic current generated during defibrillation comprises a cardiac and extracardiac component. Changes in impedance of transthoracic pathways will alter the transmyocardial current and may thus affect the outcome from defibrillation. The lungs comprise a large component of extracardiac tissue but the effects of different respiratory gases on transthoracic impedance ...

Static respiratory mechanics were examined in the armadillo (Dasypus novemcinctus) and compared with allometric relationships newly derived for adult mammals from values in the literature. Normalised by body weight, chest wall compliance (Cw) in the armadillo is lower than predicted. Lung compliance (Cl) is also low in the armadillo, however ...

Ventilatory functions were studied in 36 male and 35 female subjects (mean age 18.5 years), who underwent six weeks course in forced breathing. Ventilatory functions were studied in the form of Forced Vital Capacity (FVC), Forced Expiratory Volume at the end of one second as % of FVC (FEV1%), Maximum ...

The effects of variations in cyclic breathing parameters (i.e., tidal volume and breath frequency) have been the subject of few studies devoted to the deposition of submicrometer aerosols in the human respiratory tract. Therefore, a series of experiments was performed to investigate whether the deposition efficiency (DE) of sidestream cigarette ...

In upper airway obstruction (UAO) the relationship between the degree of obstruction, exercise limitation and lung function indices is not well established. Therefore, we investigated in nine healthy subjects (age 36+/-9 yrs) the effects of two added resistances at the mouth (R1 = added resistance with 7.8 mm diameter; R2 ...

Breath-by-breath pulmonary function testing at the bedside is now available both with special-purpose stand-alone equipment and with the new generation of ventilators. The authors studied the variability of, reproducibility of, and ideal length of data collection for nine indices of pulmonary function that may be useful for ventilatory management, weaning, ...

Pulmonary complications after upper abdominal surgery are usually ascribed to temporary postoperative impairment of diaphragm function, which may not originate from intrinsic, structural injury but from reflex inhibition of diaphragm contractility. Spontaneous breathing is interrupted periodically by sighs, even after upper abdominal surgery. If postoperative dysfunction of the diaphragm arises ...

STUDY OBJECTIVES: Criteria used to define the respective roles of pulmonary mechanics and cardiovascular disease in limiting exercise performance are usually obtained at peak exercise, but are dependent on maximal patient effort. To differentiate heart from lung disease during a less effort-dependent domain of exercise, the predictive value of the ...

This study aimed to investigate the effects of hyperoxic gas breathing on the disappearance of blood lactate after exercise in two groups having different physical fitness and to determine the most effective O2 concentration in consideration of workload. Our previous study has demonstrated that hyperoxic gas breathing brought out different ...

The spectra of sounds recorded over the trachea of adults typically reveal peaks near 700 and 1500 Hz. We assessed the anatomical determinants of these peaks and the conditions contributing to their presence. We studied five adult subjects with normal lung function, measuring sounds at the suprasternal notch and on ...

BACKGROUND: Although centrilobular emphysema, and small airway, interstitial and alveoli inflammation can be detected pathologically in the lungs of smokers with relatively well preserved lung function, these changes are difficult to assess using available physiological tests. Because submaximal single breath washout (SBWSM) manoeuvres improve the detection of abnormalities in ventilation ...

Peak oxygen consumption is a commonly accepted criterion in patient selection for cardiac transplantation. To determine the effect of various gas exchange sampling intervals on the variability of peak oxygen consumption, 15 consecutive patients evaluated for cardiac transplantation performed maximal treadmill testing using a ramped protocol. Oxygen consumption was measured ...

We determined the pulmonary diffusing capacity (DL) for 18O-labeled CO2 (C18O2) and nitric oxide (NO) to estimate the membrane component of the respective gas conductances. Six anesthetized paralyzed rabbits were ventilated by a computerized ventilatory servo system. Single-breath maneuvers were automatically performed by inflating the lungs with gas mixtures containing ...

PURPOSE: To assess whether entrainment of breathing (E) during exercise: 1) differed according to the test protocol in well-trained triathletes, and 2) improved ventilatory efficiency during exercise. METHODS: Eight triathletes performed three incremental tests until exhaustion: while cycling (CE), while running at increasing grade and constant speed (increasing GRADE) and ...

Performance of a wind instrument requires appreciable lung volume and diaphragmatic mechanical force, skilled breath control, adequate patency and humidity of air passages, and precise coordination of the oropharyngeal cavity. Depending on the instrument class, variable rates of air flow, pressure, and duration are necessary to produce optimal tone quality. ...

BACKGROUND AND PURPOSE: It has been reported that breathing exercise by immersion in combination with expiring into water improved pulmonary function and blood-gas exchange in patients with chronic obstructive pulmonary disease (COPD). This effect may result from respiratory muscle exercise against hydraulic pressure and decreased dead space by increased sub-abdominal ...

PURPOSE: To determine the effectiveness of grading such surgery according to the magnitude of the V pattern and inferior oblique muscle overaction (IOOA). METHODS: We retrospectively reviewed all 53 cases we operated since 1984 for V pattern with IOOA, who had undergone graded inferior oblique recession, recessed according to the ...

Compressed breathing air, used in self-contained breathing apparatus (SCBA) by firefighters and other categories of workers as well as by recreational and commercial divers, is prepared with the aid of high-pressure compressors operating in the range of 5000 psig. There have been reports of unexplained deaths of SCUBA divers and ...

Ninety male Vietnam veterans with posttraumatic stress disorder (PTSD) were administered relaxation instructions, relaxation instruction with deep breathing exercises, or relaxation instructions with deep breathing training and thermal biofeedback. Improvement appeared on only 4 of the 21 PTSD and physiological dependent variables studied. All 21 Treatment x Time interactions were ...

In anesthetized rats, vagal afferent activities activate slow central mechanisms which modulate the pattern of breathing over several breaths, giving rise to increased breath to breath variability of respiratory pattern. We hypothesized that variability in breathing pattern would produce variability in blood gases and further enhance breath to breath variability ...

In exercising quadrupeds, limb movement is often coupled with breathing frequency. This finding has lead some investigators to conclude that locomotory forces, associated with foot plant, abdominal visceral displacements or lumbo-sacral flexion, are the primary determinants of airflow generation. Analysis of respiratory muscle electrical activation (EMG) and contraction profiles in ...

The purpose of this study is to evaluate effects of breathing hyperoxic gas on blood lactate disappearance after submaximal exercise in two different physical fitness groups and to clarify the most effective oxygen concentration in each group. Fourteen healthy male students participated as subjects in this study. They were divided ...

The breath-to-breath measurement of total respiratory ozone (O3) uptake requires monitoring O3 concentration at the airway opening with an instrument that responds rapidly relative to the breathing frequency. Our original chemiluminescent analyzer, using 2-methyl-2-butene as the reactant gas, had a 10% to 90% step-response time of 110 msec and a ...

1. Oxygen administration is thought to suppress periodic breathing (PB) by reducing carotid body activity, and yet earlier experiments in neonates have shown that PB incidence may be increased following the application of hyperoxia. To clarify this paradox, we studied the changes in the pattern of PB that occur following ...

STUDY OBJECTIVES: We sought to determine the adaptability and effectiveness of a new esophageal balloon technique to measure changes in esophageal pressure (Pes) as a reflection of pleural pressure with progressive incremental exercise testing in normal subjects. DESIGN: An 8F (0.9 cm) esophageal balloon catheter (Smart Cath; Allied Health Products; ...

A reflex resulting in a deep, sigh-like inspiratory effort (augmented breath) is frequently triggered during synchronized mechanical ventilation in preterm infants. We studied the incidence of augmented inspiratory efforts and their effect on ventilation and lung compliance during conventional IMV and synchronized IMV (SIMV) in 15 preterm neonates (GA 26.7 ...

BACKGROUND: Closed circuit oxygen rebreathing diving apparatus are used by armed forces in special tasks because of their advantages of long endurance, low noise and minimal gas escape. There is little knowledge about the administered oxygen concentrations in these systems. Closed circuit oxygen rebreathing apparatus are also used as a ...

STUDY OBJECTIVE: To evaluate a new method of treating pneumothorax: having the subject breathe a helium/oxygen mixture (heliox). METHODS: We conducted a prospective, randomized, controlled study of nine white rabbits weighing 2.5 to 3.5 kg. Experimental pneumothorax was induced in all rabbits with the injection of 20 mL of air ...

Changes in arterial PCO2 (PaCO2) and body temperature normally occurring at the moment of birth may play a role in the initiation and maintenance of continuous breathing. To clarify these mechanisms, five chronically instrumented fetal lambs were connected to an extracorporeal membrane oxygenation (ECMO) system. ECMO was initiated in utero ...

The incidence of an 18 day chair-restraint on the digestive physiology of male rhesus monkey was investigated for space research purposes, comparing four trained restraint subjects with two vivarium controls. Chair-restraint induced a 2.5-fold acceleration of the gastrointestinal transit time, which persisted throughout the 7 day postrestraint period, and an ...

The goal of our study was to determine whether evidence for chaos in heart rate variability (HRV) can be observed when the respiratory input to the autonomic controller of heart rate is forced by the deterministic pattern associated with periodic breathing. We simultaneously recorded, in supine healthy volunteers, RR intervals ...

The substitution of a normoxic helium mixture (HeO2) for room air (Air) during exercise results in a sustained hyperventilation, which is present even in the first breath. We hypothesized that this response is dependent on intact airway afferents; if so, airway anesthesia (Anesthesia) should affect this response. Anesthesia was administered ...