Search Results
Results 451 - 500 of 825
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Gill J S - - 1993
This study examines the efficacy of verapamil for the suppression of idiopathic ventricular tachycardia (VT) of left bundle branch block LBBB-like morphology. Forty-two patients (mean age 36.2 +/- 12.1 years; 20 men and 22 women) with VT and without any underlying cardiac abnormality on clinical examination and noninvasive investigation were ...
Sawyer E H - - 1993
This study documented the effect of inspiratory muscle conditioning in children with cystic fibrosis. Subjects, ages 7 to 14 years, were divided into two groups. The experimental group (n = 10) trained at a high pressure load (> or = 29 cm H2O) and the control group (n = 10) ...
Cotton R B - - 1993
To describe the physiologic effects of surfactant treatment on gas exchange in human premature infants with hyaline membrane disease, functional residual capacity (FRC), tidal volume (VT), the alveolar portion of tidal volume (VA), alveolar ventilation (VA), nitrogen clearance index, effective breath fraction calculated as VA/VT, compliance of the respiratory system, ...
Tolentino-Silva F P - - 1993
1. To study the action of the intermediate area (IA), coextensive with the rostral ventrolateral medulla, on the neurophysiological mechanisms involved in the regulation of respiration, in terms of inspiratory drive and respiratory timing, cats were submitted to topical application of sodium pentobarbital (30 mg/ml), leptazol (200 mg/ml), glutamate (50 ...
Xu F - - 1993
Effects of inspiratory tracheal occlusion (TO) on respiratory duration (inspiratory and expiratory duration), ventilation, and the peak integrated diaphragm electromyographic (integral of EMGdi) response were tested in 16 anesthetized cats before and after decerebellation with and without vagal input. The same protocols were repeated in the decerebrate preparation. Decerebellation did ...
Suzuki S - - 1993
We studied whether inspiratory muscle training (IMT) changed respiratory sensation during exercise in 12 healthy women; IMT was performed twice daily, for 15 minutes, using a pressure threshold device and continued for 4 weeks. The inspiratory threshold was set to 30 percent of each individual's maximal inspiratory pressure (Pimax). Breathing ...
Wozniak J A - - 1993
Term human newborns were challenged with a 2-3% CO2 gas mixture during quiet sleep. A common ventilatory response, consisting of increased tidal volume with no change in respiratory frequency or timing, was observed in all eight subjects. Minute ventilation and mean inspiratory and expiratory flow rates were elevated in all ...
Grassi B - - 1993
This study, aimed at investigating some aspects of breathing control at work, was conducted on 8 heart and lung transplant recipients (HLTR) (age 33 +/- 13 years, mean +/- SD; 10 +/- 6 months post-transplantation) and on two control groups, i.e. 11 heart transplant recipients (HTR) and 11 healthy untrained ...
Breslin E H - - 1993
Many daily activities, from basic grooming to employment tasks, require adequate unsupported arm endurance (UAE). We developed an electromechanical device to measure UAE endurance. The purpose of this study was to standardize the instrument for two rates of arm motion, moderate and slow, in 18 normal adult subjects (FEVI = ...
Butler P J - - 1993
A new design of flowmeter is described and used in a comprehensive study of the respiratory and cardiovascular adjustments that occur during a standardised exercise test in Thoroughbred horses. The flowmeter system and associated lightweight, fibreglass mask (total mass, 0.7 kg) have a maximum dead space of 500 ml and ...
Goodman N W - - 1993
Spontaneous augmented breaths (active sighs) reduced the tidal volume and inspiratory time of succeeding breaths; manual lung inflations (passive sighs) reduced the tidal volume but had little effect on inspiratory time. Sighs in air, whether active or passive, reduced tidal volume more than sighs in hyperoxia (100% oxygen or 33% ...
Pellegrino R - - 1993
To investigate the impact of expiratory flow limitation (FL) on breathing pattern and end-expiratory lung volume (EELV), we imposed a small expiratory threshold load for a few breaths during exercise in nine volunteers (29-62 yr): six were healthy and three had mild-to-moderate airflow obstruction (67-71% predicted forced expiratory volume in ...
Babb T G - - 1993
There is presently no precise way to determine ventilatory capacity for a given individual during exercise; however, this information would be helpful in evaluating ventilatory reserve during exercise. Using schematic representations of maximal expiratory flow-volume curves and individual maximal expiratory flow-volume curves from four subjects, we describe a technique for ...
Sharp J T - - 1993
Previous work has suggested that diaphragm EMGs recorded from the lower thoracic wall yield spuriously low centroid frequencies (Fc). For this reason we compared EMGs recorded from two anterolateral thoracic wall locations with EMGs recorded simultaneously from a bipolar esophageal electrode in 11 stable quadriplegic patients. Their maximal inspiratory pressures ...
Torres A - - 1993
We examined diaphragmatic mechanics in awake sheep during quiet breathing (QB) and the randomized application of 5, 10, and 15 cmH2O continuous positive airway pressure (CPAP), inspiratory pressure support (IPS), and equal combinations of IPS and CPAP (IPS/CPAP). We measured esophageal, gastric, and transdiaphragmatic (Pdi) pressures and regional length, shortening, ...
Pansard J L - - 1993
BACKGROUND: Upper abdominal surgery (UAS) induces diaphragmatic dysfunction. Thoracic extradural block (TEB) using 0.5% bupivacaine improves some pressure and motion indices of diaphragmatic function. However, no direct information on diaphragmatic activity is available after UAS. The aim of this study was to assess diaphragmatic electrical activity (Edi) after UAS before ...
Choukroun M L - - 1993
The breathing pattern and respiratory muscle function were investigated in ten trained and ten untrained adolescents (aged 15-16 years) while undergoing an incremental intensity exercise test on a cycle ergometer up to 80% maximal oxygen consumption (VO2max), maintained to exhaustion. Before and after exercise, maximal inspiratory (PImax) and expiratory (PEmax) ...
Calkins H - - 1993
The objective of this study was to compare prospectively the efficacy of fixed burst pacing with that of decremental burst pacing in terminating VT. Forty-four patients with inducible sustained monomorphic VT were studied. The efficacy of fixed burst and decremental burst pacing for terminating 57 distinct types of VT were ...
Salvadori A - - 1993
More rapid and more shallow breathing (RSB) than usual, manifested by a lower tidal volume and greater breathing frequency at a given level of ventilation, may be caused by inspiratory muscle fatigue and pulmonary congestion. It has been observed during recovery in young trained adults after very high exercise levels ...
O'Donnell D E - - 1993
Patients with quadriplegia have a limited capacity to recruit expiratory muscles and are deprived of respiratory-related feedback from the rib cage and abdominal wall. We wished to evaluate the compensatory strategies available to such patients during expiratory resistive loading (ERL) and to compare their responses with those of normal healthy ...
Burnet H - - 1992
When breathing room air at sea level the expired gas temperature (TE) increases in proportion to the inspired one (TI). Previous studies conducted under hyperbaric conditions have assumed that the TE vs TI relationship was the same when humans breathed room air at atmospheric pressure or helium-oxygen mixture under hyperbaric ...
Gill J S - - 1992
This study examines the efficacy of verapamil and diltiazem in the suppression of idiopathic ventricular tachycardia (VT). Eight patients (mean age 29.8 +/- 12.3 years, two males and six females) with VT, without any underlying cardiac abnormality on clinical examination and noninvasive investigation, were studied. The inducibility of the clinical ...
Bashir Y - - 1992
Combination antiarrhythmic drug therapy may be more effective than treatment with a single agent for control of refractory cases of sustained ventricular tachycardia (VT). In a prospective randomized crossover study of 20 patients with impaired left ventricular function (ejection fraction of 28% +/- 8%) and recurrent VT in spite of ...
Livingston M - - 1992
Thirty patients with low back pain were referred for examination by their doctors after 3 or more weeks of treatment. Whether back exercise instruction had been given, who had given it, what it was, and whether the patients actually followed the instruction was noted. Some type of back exercise had ...
Caretti D M - - 1992
Ventilatory patterns and respiratory timing were measured in 14 subjects during cycling (CYC) and treadmill exercise (TM) at similar leg frequencies (fLEG) to determine if mode of exercise affects patterns of ventilation and respiratory timing. Measurements of breathing frequency (fR), tidal volume (VT), expired ventilation (VE), and inspiratory (TI) and ...
Belz M K - - 1992
The differentiation between ventricular tachycardia (VT) and sinus tachycardia (ST) is problematic in some patients with implantable defibrillators and/or antitachycardia pacemakers. The integral of the ventricular endocardial evoked response, or paced depolarization integral (PDI), has been demonstrated to undergo characteristic changes with a variety of stimuli including catecholamines, pacing rate, ...
Manning H L - - 1992
The act of breathing diminishes the discomfort associated with hypercapnia and breath-holding. To investigate the mechanisms involved in this effect, we studied the effect of tidal volume (VT) on CO2-evoked air hunger in 5 high-level quadriplegic subjects whose ventilatory capacity was negligible, and who lacked sensory information from the chest ...
Babb T G - - 1992
To investigate the impact of expiratory airflow limitation on ventilation during exercise, we studied six control subjects with normal lung function (FEV1/FVC = 79 +/- 6%) and eight patients with borderline-to-mild airflow limitation (FEV1/FVC = 68 +/- 4%) during cycle ergometry. VO2, HR, and VE/MVV were not different between the ...
Puddy A - - 1992
We wished to determine the independent effect of inspiratory flow rate (VI) on respiratory output in the awake state. Seven normal subjects were connected to a volume-cycled ventilator in the assist/control mode. While the tidal volume setting remained constant, inspiratory flow rate was increased in steps (3 to 4 min ...
Johnson B D - - 1992
We determined how close highly trained athletes [n = 8; maximal oxygen consumption (VO2max) = 73 +/- 1 ml.kg-1.min-1] came to their mechanical limits for generating expiratory airflow and inspiratory pleural pressure during maximal short-term exercise. Mechanical limits to expiratory flow were assessed at rest by measuring, over a range ...
Boggs D F - - 1992
An analysis of breathing pattern regulation was carried out on the coatimundi and woodchuck who represent two different volume-time patterns. It was found that the coati, with a short expiratory time as a fraction of total breath time, TE/TTOT, has a greater sensitivity to CO2 as represented by the slope ...
Loveridge B - - 1992
The alterations in lung function and breathing pattern were examined in 6 quadriplegics at 3, 6 and greater than 12 months post injury, and were compared to 6 able bodied controls. Subjects were studied in both the seated and supine positions. Functional residual capacity (FRC), forced vital capacity (FVC), inspiratory ...
Hsia C C - - 1992
In three foxhounds after left pneumonectomy, the relationships of ventilatory work and respiratory muscle (RM) blood flow to ventilation (VE) during steady-state exercise were examined. VE was measured using a specially constructed respiratory mask and a pneumotach; work of breathing was measured by the esophageal balloon technique. Blood flow to ...
Kobylarz E J - - 1992
We used an esophageal electrode to measure the amplitude and neural inspiratory and expiratory (N TE) timing responses of crural diaphragmatic electrical activity in response to flow-resistive (R) and elastic (E) loads at or below the threshold for conscious detection, applied pseudorandomly to the oral airway of eight normal subjects. ...
Yasukouchi A - - 1992
Breathing patterns and subjective responses to small resistances were investigated in seven subjects during moderate exercise. Inspiratory resistances of 0.15 (R1), 0.25 (R2) and 0.30 (R3) kPa.l-1.s were tested against control of 0.06 kPa.l-1.s with no added resistance. Subjective responses to small inspiratory resistances were evaluated through whole experiments including ...
Wanke T - - 1992
The aim of this study was to evaluate the difference between Type 1 (insulin-dependent) diabetic patients and healthy control subjects regarding inspiratory muscle load during exercise hypernea. For this purpose an incremental progressive exercise test on a cycle ergometer was performed by 36 Type 1 diabetic patients and 40 healthy ...
Poon C S - - 1992
A previous optimal chemical-mechanical model (C.-S. Poon. J. Appl. Physiol. 62: 2447-2459, 1987) suggested that the normal ventilatory responses to CO2 and exercise inputs and mechanical loading can be predicted by the minimization of a controller objective function consisting of the total chemical and mechanical costs of breathing. In this ...
Bhatt S B - - 1992
Laryngeal mask airways and tracheal tubes were studied to determine both their resistance to constant gas flows and additional inspiratory work during simulated inspiration. Laryngeal mask airways imposed less resistance and required lower additional inspiratory work compared with the corresponding sized tracheal tubes. If inspiratory loading during anaesthesia is an ...
Painter R - - 1992
Respiratory drives follow various afferent pathways to the respiratory centres; nevertheless, steady-state breathing patterns described in terms of tidal volumes and phase durations are largely independent of the nature of the respiratory stimulus. Flow has now been recorded during steady states from six subjects in rest and hyperpnoea induced by ...
Hatfield B D - - 1992
Twelve aerobically trained males (age 22 +/- 1.3 yr, range 18-31) were studied to determine the effects of VE and EMG feedback upon cardiorespiratory and muscular activity during one segment of a continuous 36-min bout of treadmill running just below ventilatory threshold (VT). Ventilatory, metabolic, cardiovascular, RPE, and EMG variables ...
Baydur A - - 1992
The decay of pressure developed by the inspiratory muscles during expiration (PmusI) has not been studied in subjects with increased respiratory impedance such as in kyphoscoliosis. PmusI was compared in 11 anesthetized patients with kyphoscoliosis with that in 11 anesthetized normal subjects. PmusI was obtained according to the following equation: ...
Fontana G A - - 1992
We studied the influence of mastication on respiratory activity in nine healthy volunteers who were requested to masticate a 5-g chewing gum bolus at a spontaneous rate (SR) for 5 min and "at the maximum possible rate" (MPR) for 1 min. Significant increases in respiratory frequency were induced by SR ...
Mateika J H - - 1992
These experiments examined the effect of exercise intensity and duration on the magnitude of the abrupt change in ventilation at the start (VE,start) and end (VE,end) of exercise. Five subjects performed constant load treadmill exercise at 50% and 80% of their maximum oxygen consumption (VO2max) for 6 and 10 min ...
Fiz J A - - 1992
We studied the effect of order in the performance of maximal respiratory pressures (PImax and PEmax). For this purpose 20 healthy subjects (male/female: 1/1) were studied. PImax and PEmax were obtained on 2 different days at the same hours (9 and 12 a.m.). The test order was random. On the ...
Barnas G M - - 1992
Dependences of the mechanical properties of the respiratory system on frequency (f) and tidal volume (VT) in the normal ranges of breathing are not clear. We measured, simultaneously and in vivo, resistance and elastance of the total respiratory system (Rrs and Ers), lungs (RL and EL), and chest wall (Rcw ...
Voorhuis T A - - 1991
Groups of juvenile and 1-year-old male canaries were treated briefly with the vasotocin (VT) analog desGly(NH2)9d(CH2)5-[Tyr(Me)2,Thr4, Orn8]VT (dGVTA) during four time intervals between September and February. The canaries received subcutaneously testosterone-containing silastic implants at the start of the VT analog treatment to assure that despite age and season differences the ...
Dempsey, Jerome A.
We have more precisely than has been done before, defined the mechanical limits of the lung and chest wall for the ventilatory requirements of exercise in healthy persons. In most instances in the normal or moderately fit individual the ventilatory requirement is such that mechanical limitations are barely reached upon ...
Ramonatxo M - - 1991
In healthy subjects, we compared the effects of an expiratory (ERL) and an inspiratory (IRL) resistive load (6 cmH2O.l-1.s) with no added resistive load on the pattern of respiratory muscle recruitment during exercise. Fifteen male subjects performed three exercise tests at 40% of maximum O2 uptake: 1) with no-added-resistive load ...
Seliga R - - 1991
The effects on postural stability (sway) were investigated for different work loads under conditions of wearing a full facepiece respirator and not wearing any respiratory protection device. Fifteen subjects accomplished light (40 W), moderate (85 W), and heavy (125 W) work loads under the two conditions. Measurements of postural sway ...
Mont L - - 1991
In 37 (70%) of 53 patients with idiopathic ventricular tachycardia (VT), episodes were mainly related to exercise (group 1). These patients were younger (33 +/- 14 vs 44 +/- 18 years, p = 0.015) and more often had dizziness during VT (71 vs 40%, p = 0.003) than the 16 ...
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