Two cases of proven bites by the Cape cobra (Naja nivea) are reported. Both patients developed areflexic flaccid paralysis and required ventilation from 2 1/4 and 2 1/2 hours after the bite for 4 1/2 and 7 days respectively. Antivenom is of value before the onset of paralysis but of ...

The effects of indomethacin on the relationship between breathlessness and minute ventilation during exercise have been determined in a double-blind, randomized study on 6 normal subjects. Indomethacin did not significantly after ventilation or oxygen uptake either at rest or during submaximal exercise. Breathlessness was assessed with visual analogue scales, and, ...

To examine the mechanism of exercise limitation associated with chest wall restriction (CWR), we compared the ramp (1 W/3 s) exercise performance of six untrained subjects with ankylosing spondylitis (AS) and six healthy subjects matched for age and body size. Subjects with AS had CWR (maximum rib cage expansion : ...

Previous work has left unresolved questions on whether promethazine reduces the sensation of breathlessness. This study was designed to provide a definitive answer and to determine the contributions from promethazine's major pharmacological actions. Twelve healthy subjects participated in a double-blind, within-subject comparison of promethazine and placebo each given acutely by ...

Six Hereford steers were studied before, during, and after short exercise bouts on a motor-driven treadmill (3 degrees incline) at four speeds (1.0, 1.4, 1.8, and 2.2 m X s-1). Oxygen consumption (MO2) and carbon dioxide production (MCO2) were measured by collecting the expired gas. Arterial and mixed venous blood ...

A new method for evaluation of changes in the distribution of pulmonary perfusion and ventilation during exercise was applied to normal male volunteers. Ventilation and perfusion scans were done with the subjects seated on a bicycle ergometer. The resting studies utilized krypton 81 (81mKr) for ventilation and technetium 99m (99mTc) ...

Nine men with severe chronic obstructive airways disease (COAD), known to desaturate on exercise, performed a 6 min self-paced walk on a treadmill, followed by a bicycle exercise with workloads adjusted to mimic the oxygen consumption achieved on the treadmill. During both exercises, ventilation, oxygen consumption, carbon dioxide production, PaO2, ...

It remains unclear whether the hyperpnea of exercise severely stresses the ventilatory musculature. We hypothesized that the ability to ventilate maximally is decreased during and immediately following exhausting exercise. Subjects performed isocapnic maximal voluntary ventilations (60-s MVV) before, during the final minute, and after exhausting treadmill exercise lasting either 3-10 ...

We describe a patient with respiratory failure who demonstrated marked increases in O2 consumption (VO2) when breathing with synchronized intermittent mandatory mechanical ventilation (SIMV). When the mode of ventilation was changed to facilitate inspiratory gas flow (pressure-support) during spontaneous breathing, O2 consumption decreased 27 percent. Several important factors contributing to ...

The hypoxemia of acetate hemodialysis may result from a decrease in alveolar ventilation (VA) related to a reduction in pulmonary carbon dioxide excretion (VCO2). To test this theory, ventilation was increased by exercise during dialysis on 6 patients and the effect on arterial oxygen tension (PaO2) measured. With hemodialysis the ...

Two groups of eight patients received infusions of either fentanyl at 3 micrograms kg-1 h-1 or alfentanil at 20 micrograms kg-1 h-1 as supplements to 66% N2O in oxygen anaesthesia, during and after body surface surgery. At the end of surgery, the N2O was reduced to 50% and after measurement ...

The effects of whole body hypothermia on metabolism, blood and medullary acid-base, and respiratory variables were determined in 29 paralyzed, vagotomized and glomectomized cats. Respiratory output was quantified from integrated phrenic nerve activity. Metabolic rate (VCO2) decreased progressively as temperature decreased. When end-tidal PCO2 was kept constant by decreasing artificial ...

Changes at the beginning of isometric and dynamic low level exercise were studied in 23 patients with chronic lung disease. Ventilation, oxygen consumption and vascular pressures in systemic and pulmonary circulation were continuously monitored, and cardiac output was measured by thermodilution every minute. Circulatory changes took place suddenly at the ...

The consensus of available studies indicates that high-frequency jet ventilation (HFJV) can adequately ventilate animals in respiratory failure, although a clear superiority to volume-cycled ventilation (VCV) cannot be established. HFJV is probably useful in the presence of airway disruption and in tracheal or pulmonary surgery. Clinical trials and additional bench ...

A study was undertaken to determine the pattern of arterial blood gas (ABG) concentration in the canine model undergoing prolonged cardiopulmonary resuscitation (CPR) from fibrillatory arrest, and to determine the importance of acid base abnormalities in predicting resuscitation. Ventricular fibrillation was induced electrically in 12 dogs. CPR was begun at ...

During acute respiratory acidosis increments in cisternal cerebrospinal fluid (CSF) [HCO3-] approximate decrements in CSF [Cl-] with CSF [Na+] remaining unchanged; the mechanisms mediating this reciprocal anionic relationship are unclear. In the present study we investigated the effects of DIDS (4,4'-diisothiocyano-disulfonic stilbene), a known inorganic anion exchange blocker, on CSF ...

One hundred patients were ventilated with high-frequency jet ventilation (HFJV) during the initial 24-h postoperative period in the surgical and neurosurgical ICUs. Eighty-three were successfully weaned, 2 could not be ventilated adequately with HFJV, and 15 with criteria of acute respiratory failure received HFJV for up to 21 days. A ...

The feasibility of the thermodilution technique to measure cardiac output (CO) during positive pressure ventilation was assessed in 12 critically ill patients. An indicator (5 ml of 5% glucose in cold water) was injected at the mid and end of the inspiratory and expiratory phases of mechanical ventilation to see ...

The relative effect of the temperature on respiratory rhythm generation was studied in muscle-relaxed, artificially ventilated and bilaterally vagotomized rabbits under general anaesthesia (urethane and chloralose). Hypercapnia was produced during normothermia (38.8 +/- 0.6 degrees C) and hyperthermia (40.5 +/- 0.3 degrees C). The basic physiological parameters, efferent phrenic nerve ...

The efficiency of oxygenation and the uniformity of the distribution of regional ventilation (Vr) to regional perfusion (Qr) along the vertical and horizontal axes was compared in anesthetized dogs between conventional mechanical ventilation (CMV) and high-frequency ventilation (HFV) at 5.8, 15.0, and 29.8 Hz. Both CMV and HFV were adjusted ...

Seizure duration in unilateral electroconvulsive therapy (ECT) was recorded by means of EEG in an intraindividual comparison under different alveolar O2- and CO2-concentrations. Hypocapnia induced by hyperventilation to an alveolar CO2-concentration of 2% (2 kPa) resulted in a highly significant increase in seizure duration compared to a normal CO2 of ...

Although minute ventilation (VE) exhibits marked increases during heavy rhythmic exercise utilizing a large muscle mass, the extent to which this hyperpnea stresses the respiratory muscles remains controversial. In an attempt to resolve this matter, we measured arterial blood lactate concentration during seated isocapnic reproduction of peak exercise ventilation. This ...

The effects of ICI 118,587 and atenolol on the responses to submaximal exercise and on breathlessness were studied in six healthy subjects. Atenolol reduced heart rate at rest and during exercise whereas ICI 118,587 increased resting heart rate but caused a small reduction in the highest heart rate achieved during ...

A double-blind, placebo-controlled, crossover study of the effects on regional lung function of oral almitrine bismesylate at a dose of 3 mg X kg-1, was carried out in six patients with severe chronic airflow obstruction. Oxygen saturation (SaO2) was measured by ear-lobe oximetry and ventilation (VE) by inductance plethysmography. Radionuclide ...

Changes in the duration and size of the vulnerable period of the myocardium in the presence of respiratory changes were studied in acute experiments on rats. The limits of the vulnerable period were determined by directly stimulating the heart during ventilation via the enlarged respiratory dead space, during hyperventilation and ...

The effects of spontaneous high-frequency breathing (HFB) on lung function were evaluated in three subjects highly trained in the practice of yoga. Transpulmonary pressure was measured by an esophageal balloon catheter and gas flow by pneumotachography. The abdominal and rib cage contributions to tidal breathing were measured separately by respiratory ...

Ventilation and acid-base balance were studied in 6 conscious dogs during chronic eucapnic and hypocapnic metabolic acidosis. The dogs had tracheostomas for respiratory studies, exteriorized carotid arteries for obtaining arterial blood and cannulae for sampling cisternal cerebrospinal fluid (CSF). Measurements were obtained on a control diet, and then, during metabolic ...

To evaluate independently the effects of an inspiratory stimulus (a mouthpiece) and a ventilatory depressant (oxygen) on minute ventilation (VE) in asthma, we measured VE with magnetometers in 18 asthmatic subjects. When room air was inspired from a loose-fitting mask, VE was 10.2 +/- 0.6 L/min. When oxygen was substituted ...

Effects of a new respiratory stimulant almitrine on lung ventilation and gas exchange were studied in 15 patients suffering from chronic respiratory insufficiency. The variables examined were measured during 4 consecutive periods lasting 30 min each. During the first period initial data were collected. From the second period to the ...

Resting lung volume (FRC), airway closure (CC) and ventilation-perfusion relationships, using the multiple inert gas elimination technique, were studied during epidural analgesia. The material consisted of 10 patients, 55-84 years of age. Epidural blockade (9-13 ml mepivacaine-adr, 1/200,000) was instituted to an upper level corresponding to Th3-Th6. Minute ventilation and ...

In high decerebrate unanaesthetized cats (pre-collicular/pre-mamillary) which developed spontaneous co-ordinated locomotor activity, ventilation, breathing pattern, phrenic nerve, external and internal intercostal electromyogram (e.m.g.) activities were examined. Locomotion was also induced by electrical stimulation of the subthalamic locomotor region and in a few cases the mesencephalic locomotor region. Quadriceps muscle e.m.g. ...

The purpose of this study was to investigate the physical work capacity of adolescent patients with mild idiopathic scoliosis (less than 60 degrees). Fourteen subjects, who were being treated with a Milwaukee brace, were given a progressive exercise stress test. Ventilatory volume, frequency of breathing, end-tidal PCO2, heart rate, and ...

We measured ventilation and static lung volumes in five fit volunteers in the right lateral decubitus position, while they were fully awake and while sedated with diazepam. We also assessed the distributions of ventilation and perfusion in the lungs, using inhalations and intravenous injections of xenon-127. Diazepam, 0.04 mg . ...

To determine the involvement of intrapulmonary chemoreceptors (IPC) in the control of breathing during exercise, it is necessary to hold the PCO2 in the microenvironment of these receptors constant at the resting value. We accomplished this in unanesthetized Pekin ducks by ligating the left pulmonary artery and diverting all of ...

Mechanical ventilation of paralyzed, pentobarbital-anesthetized adult cats was performed while recording phrenic nerve activity. The periodic changes in lung volume owing to mechanical ventilation affected the rhythm of central respiratory activity, resulting in a variety of regular and irregular patterns of coupling between respiratory system output, monitored by phrenic activity, ...

Comparison of diffusive and convective transport equations for O2, CO2 or H2O in the gas-phase shows that for the same gas flux (ml . day-1) and the same pressure difference (Torr) one can substitute an effective air ventilation, VA (ml . day-1), for a given diffusive conductance, G, (ml . ...

In six healthy subjects, respiration and the sensation of breathlessness were assessed during submaximal exercise and the subsequent recovery. The overall responses were expressed by the relationship of breathlessness to minute volume. Because of the high subjective component in the assessments, validation of the method in these particular subjects was ...

The fast component of the ventilatory changes that occur at the transition phases of exercise was studied in awake dogs trained to run on a treadmill. Two questions were examined: firstly, is the fast ventilatory component modified by changes in venous return to the lungs, such as those consecutive either ...

The role of the sinoaortic reflexes in the regulation of ventilation during exercise was evaluated in seven awake dogs prepared with chronic tracheostomies and arterial catheters. Each dog ran on a treadmill at several work loads before and after sinoaortic denervation and served as its own control. Minute ventilation in ...

During steady-state exercise, ventilation increases in proportion to CO2 output (VCO2), regulating arterial PCO2. To characterize the dynamics of ventilatory coupling to VCO2 and O2 uptake (VO2) in the nonsteady-state phase, seven normal subjects performed constant-load cycle ergometry to a series of subanaerobic threshold work rates. Each bout consisted of ...

20 anesthetized mechanically ventilated dogs received an infusion of epinephrine, 2 micrograms/kg/min, for 4 h. 10 dogs were ventilated with air for the entire 4-hour period and 10 were ventilated with oxygen for the first hour and then air for 3 h. During the first hour of the epinephrine infusion ...

The question of respiratory factors limiting exercise has been examined in terms of possible limitations arising from the function of gas exchange, the respiratory mechanics, the energetics of the respiratory muscles, or the development of respiratory muscle fatigue. Exercise capacity is curtailed in the presence of marked hypoxia, and this ...

Conventional one-lung intermittent positive-pressure ventilation (OL-IPPV) has been a valuable technique during anesthesia for intrathoracic operations. OL-IPPV has been associated with a high incidence of hypoxemia, as a result of the associated intrapulmonary shunt of 21% to 65% of cardiac output. The administration of OL-IPPV requires the use of a ...

Effective gas exchange can be achieved in normal dogs by ventilation at frequencies of 4-20 Hz using stroke volumes (SV) smaller than the anatomic dead space. CO2 elimination is largely a function of tracheal SV-frequency product (Vosc) in anesthetized, paralyzed dogs with normal lungs. To determine the effect of constriction ...

Kittens, puppies, cats, and dogs were anesthetized with pentobarbital sodium and tracheotomized. The ventilatory pattern was recorded before, during, and after the delivery of steady flows of room air of 20 or 50 ml X s-1 X kg-1 in the expiratory direction through a cannula inserted just below the larynx. ...

The influence of medroxyprogesterone acetate (MPA) on exercise performance was studied in a double-blind cross-over trial using six normal males to compare the exercise performance changes to those observed in a previous study of exercise responses of female subjects during the follicular and luteal phase of the menstrual cycle. A ...

We measured the oxygen cost of breathing (VO2resp) in 13 patients with cardiorespiratory disease requiring artificial ventilation as the difference between the oxygen consumption during spontaneous respiration (VO2tot) and that during artificial ventilation (VO2nonresp). Average VO2tot was 312 +/- 90 ml/min (mean +/- 1 SD), whereas VO2nonresp was 246 +/- ...

Although increased ventilation is one of the most readily observed physiological responses to exercise, it is uncertain how severely this hyperpnea stresses the ventilatory muscles. As one approach to this question, we compared short-term maximal running performance in nine subjects with and without prior ventilatory work designed to reduce ventilatory ...

We assessed ventilation-perfusion inequality in 8 anesthetized, tidally ventilated geese in terms of continuous V/Q distributions using the multiple inert gas elimination technique modified for cross-current avian lungs (Powell and Wagner, 1982). Thirty-four data sets were collected. Allowing for differences in solubility, high molecular weight gases (Enflurane, SF6) were not ...

Eleven adult patients with exercise-induced asthma (EIA) were subjected to swimming and bicycle exercise under controlled conditions regarding temperature and relative humidity of the inhaled air, the respiratory frequency, tidal volume, minute ventilation and the accumulated ventilation. Swimming for 6 min was performed on the first day, and the next ...