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At least 19 recordsLinked to original sources
PubMed1979

Influence of ventilatory frequencies and ventilator volume/pressure quotients on pulmonary ventilation using a tidal volume ventilator.

The influence of ventilatory frequency and the ventilator's "internal state of gas compression" (Cvent) on mechanics of ventilation, pulmonary ventilation, gas distribution, gas exchange and lung perfusion was studied with free airway and experimental regional airway obstruction in 10 piglets (7-12 kg b. w. ), using a tidal volume ventilator. The VDphy/VTexp ratio was greater at f = 30 than at f = 10.3 cycles/min. This could be related to a significant increase in the VDanat/VTexp ratio at f = 30, while VDc/VTexp and VDlav/VTexp were unchanged at both frequencies. With regional ventilation and perfusion within the obstructed pulmonary field were reduced, compared to the values at f = 10.3 cycles/min. With Cvent 20 ml/kPa, the tidal volumes were insufflated in a shorter time and with a higher initial tracheal peak pressure than with Cvent 80 ml/kPa. Following bronchial obstruction, VA, RQ and Pao2 were greater with Cvent 20 than with Cvent 80 ml/kPa. With Cvent 20, the ventilation of the lung bases was reduced, which was compensated for by a large increase in ventilation within the apical areas of the lungs, while gas distribution within the unobstructed areas was more evenly distributed with Cvent 80. Ventilation at Cvent 20 showed no essential advantage over Cvent 80. Only in lungs extremely difficult to ventilate and with ventilatory frequencies over 50 cycles/min could possible indications for Cvent 20 be seen.

Animals↗
PubMed1979

Experimental studies on artificial ventilation using a tidal volume ventilator. Mechanics and dynamics of ventilation.

In 24 piglets (2.7-24.5 kg b.w.), the mechanics of ventilation, the accuracy of dosage of respiratory volumes, and the influence of the ventilator's volume/pressure characteristics (Cvent, "internal compliance") on the dynamic course of insufflation were studied. A linear relationship was shown to exist between tidal volume and end-inspiratory tracheal pressure and between tidal volume and insufflation time. The insufflation time was reduced to about 50% of previously registered values. The error between set and registered tidal volume was found to be 6.0 +/- 2.7%. During the insufflation a linear relationship was found between the instant amount of delivered breathing gas and the corresponding endotracheal pressure change. The ventilator's Cvent did (and body size, total compliance and tidal volume did not) significantly influence the size of the direction coefficient for the linear instantaneous volume/pressure relationship, the magnitude of tracheal peak pressure and a short insufflation time, and vice versa. The use of greater power from the ventilator resulted in a significant shortening of the duration of insufflation and vice versa. The duration of insufflation is the parameter of choice in evaluating the efficiency of the ventilatory equipment. When the ventilator's performance is defined, measurements of the duration of insufflation may enable evaluation of conditions within the lungs.

Animals↗
PubMed1977

Weaning from mechanical ventilation by means of intermittent assisted ventilation I.A.V. Case reports.

A new ventilator is described which is capable of interposing controlled breaths synchronized with the patient's own breathing rhythm. This ventilation pattern is called "intermittent assisted ventilation" (IAV). It differs from intermittent mandatory ventilation (IMV) in that each ventilator cycle is triggered by the patient. IAV constitutes a new approach to the problems during the critical period of weaning from mechanical ventilation. Further, this new ventilator provides means for continuous display and recording of airway gas flow and pressures and expired minute volume (EMV) during different types of ventilation, e.g. controlled ventilation, intermittent assisted, and spontaneous ventilation.

Clinical Trials as Topic↗
PubMedDate not supplied

[Assisted ventilation of newborn infants during sleep. Study of factors modifying adaptation to ventilation].

During sleep, of ventilated newborns and young infants, spontaneous respiratory movements may occur, unrelated to the ventilation impulsions. The respiratory pattern is then classified as "active". On the contrary, the respiratory pattern is classified as "passive", when all respiratory movements are related to the ventilation insufflation. The factors which influence the dependence on the ventilator are studied in a group of 20 newborn and young infants. Prematurity, some biological data such as hyperoxia, hypocapnia, seem to favor this dependence. A rapid rate of ventilation (superior to 30/minute) is rarely related to an active respiration; a slow rate of ventilation seems favor this respiratory pattern. It is clear that adaptation to artificial ventilation is better during quiet sleep than during active sleep. Some physiopathological considerations are developed.

Adaptation, Physiological↗
PubMed1979

Influence of an end inspiratory pause on pulmonary ventilation, gas distribution, and lung perfusion during artificial ventilation.

Using a constant tidal volume and ventilatory frequency, anesthetized piglets were ventilated with a new tidal volume ventilator. A short inspiratory time without a pause (10% of breathing cycle) was compared with a longer inspiratory time with a pause (33%) both with and without bronchial obstruction. Mechanics of ventilation, pulmonary ventilation, gas exchange, gas distribution, and lung perfusion were measured. The longer inspiratory time with a pause resulted in lower peak airway and end inspiratory pressures and a higher total compliance. Dead space/tidal volume ratio was reduced and the RQ was increased. While the cranial pulmonary fields were less well ventilated, the right caudal field was better ventilated. In the presence of bronchial obstruction, better alveolar ventilation was achieved when an end inspiratory pause was added. The results emphasize the importance of static end inspiratory tracheal conditions although the tidal volumes were kept unchanged.

Animals↗
PubMed1979

Small endotracheal tubes: ventilator and intratracheal pressures during controlled ventilation.

The use of small endotracheal tubes reduces the trauma of intubation. Ventilator and tracheal pressures were measured during controlled ventilation with various tube dimensions and ventilation volumes. Ventilation with large volumes using small tracheal tubes results in high ventilator pressures. However, tracheal pressures are only marginally greater than those obtained with larger tubes. Small endotracheal tubes and high ventilation volumes result in a positive tracheal pressure at the end of expiration. The measured end-expiratory pressures are within the limits which might be used therapeutically (in PEEP). The force required to reshape endotracheal tubes of varvious dimensions to an "anatomical" shape was related to the tube dimensions; the beneficial effects of performed, "anatomically shaped" endotracheal tubes can be achieved by using small tubes of standard design.

Adult↗
PubMed1977

Chronic pulmonary disease in neonates after artificial ventilation: distribution of ventilation and pulmonary interstitial emphysema.

To determine pulmonary function abnormalities in patients with neonatal bronchopulmonary dysplasia (BPD), we measured distribution of ventilation by nitrogen washout, minute and tidal volume, and arterial and alveolar gases in three groups of ten preterm infants with similar birth weights (mean = 1,340 g) and gestational ages (mean = 30.3 weeks). Infants in group A were never artificially ventilated, those in group B were ventilated but had no subsequent BPD, and those in group C were ventilated and developed BPD. Infants with BPD had severe maldistribution of ventilation (pulmonary clearance delay 223% versus 47% and 60% for groups A and B). They had decreased tidal volumes (5.3 ml versus 7.0 and 6.2 ml) and higher respiratory rates (60/min versus 47 and 48) but similar minute volumes. They also had increased PaCO2 (53.6 torr versus 41.9 and 43.4 torr) and increased arterial-alveolar carbon dioxide gradients (6.8 torr versus 3.1 and 1.8 torr). There was no statistically significant difference between groups B and C for the time spent in fractional inspired oxygen greater than 0.40 and greater than 0.60, or the time ventilated for intubated, or the incidence of patent ductus arteriosus. Early pulmonary interstitial emphysema was much more common in the infants who subsequently developed BPD (eight of ten versus two of ten, P less than .01).

Chronic Disease↗
PubMed1976

[Artificial ventilation with the servo-ventilator 900 (author's transl)].

The use of artificial ventilation in the treatment of seriously ill or severely injured patients demands extensive knowledge on the part of the physician of the physiological and pathological effects of ventilation. In addition, it is required that the manufacturers develop ventilators able to meet there special demands. During the last two years the Servo-Ventilator 900 has been in use in our intensive care unit. During this period we were very impressed by its versatile applicability. The use of this apparatus however more than ever before requires the knowledge of breathing mechanisms and their pathophysiological consequences. The various flow- and breathing-rate-patterns combined with the exact electronic control of the respiratory make possible subtle adjustments--to the required ventilation pattern.

Humans↗
PubMed1975

The effect of artificial ventilation on functional residual capacity and arterial oxygenation. II. Comparison of spontaneous respiration and artificial ventilation at similar arterial carbon dioxide tensions, tidal volumes and inspiratory gas flow rates.

We have compared cardiac output, gas exchange and pulmonary mechanics during spontaneous breathing and artificial ventilaton under conditions which kept PaCO2 within the normal range and maintained constant tidal volume and inspired gas flow rate. In dogs anaesthetized with pentobarbitone and ventilated with air, artificial ventilation increased VD/VT but did not reduce Q angstrom, FRC, or CL. PaO2 increased and A-aDO2 decreased during aritificial ventilation, perhaps because of a small increase in Q angstrom and a small decrease in oxygen consumption. It appears that many of the reported deleterious effects of artificial ventilation may be due to the use of other anaesthetic agents and patterns of ventilation, and to changes in PaCO2.

Anesthesia↗
PubMedDate not supplied

Acute life-threatening ventilation-perfusion inequality: an indication for independent lung ventilation.

Although reports of independent lung ventilation are found in the literature more frequently, firm criteria for its use have not yet been established. It is probable that major ventilation-perfusion inequality, especially in cases in which the blood flow is primarily diverted to the less ventilated lung, could sometimes be corrected by this technique. The present report deals with such a case and describes the angiographic studies which convinced us that differential ventilation was necessary. By this means we were able to provide successful treatment for patients who had developed preterminal hypoxemia.

Adult↗
PubMed1976

[Effect of fominoben on ventilation, oxygen uptake and blood gases in patients with obstructive ventilation disorders].

The substituted benzylamin-derivative fominoben (PB 89 Noleptan) was intravenously administered to 12 patients with chronic obstructive lung disease in order to determine, whether an analeptic action on respiration, which had been found by others in animal studies and in healthy subjects, can also be demonstrated in patients with COLD. Time ventilation showed no statistically significant change. Respiratory rate was increased for a short time, alveolar ventilation showed a slight but significant increase 35 minutes after i.v. injection of fominoben, however no significant change in the first 10 minutes after injection.--Arterial pO2 was slightly but not significantly increased in the first 10 minutes after fominoben, while the same patients showed a significant decrease of pO2 after injection of placebo. As alveolar ventilation at this time had not significantly changed, the increase in pO2 can only be explained by an improvement of regional ventilation-perfusion ratio by fominoben. -In conclusion it can be stated, that a marked stimulative action on respiration by fominoben could not be demonstrated. There was, however, no depression of respiration as it is associated with most other caugh medications. As the drug has been shown to be an excellent caugh sedative, lack of respiratory depression can be considered as a considerable advantage.

Adult↗
PubMed1979

[Acute respiratory failure: comparison of spontaneous ventilation with continuous positive airway pressure (CPAP) and mechanical ventilation with positive and expiratory pressure (CPPV) in 6 cases (author's transl)].

The hemodynamic and respiratory effects of spontaneous ventilation with continuous positive airway pressure (CPAP) and mechanical ventilation with positive and expiratory pressure (CPPV) were compared in six patients with acute respiratory failure. Arterial and mixed venous gases, cardiac output, oxygen delivery and consumption, airway and oesophageal pressures were measured, with each patient on intermittent positive pressure ventilation (IPPV), CPAP and CPPV with the same level of positive and expiratory pressure (PEEP = 20 cmH2O). CPAP was as efficient as CPPV for improving arterial oxygenation. Cardiac output was higher on CPAP than on CPPV due to a lower intra-thoracic pressure with spontaneous ventilation, thus oxygene transport was higher with this methode. However total oxygene consumption and PaCO2 were slightly increased with CPAP due to a higher breathing's work. So, CPAP is as efficient as CPPV at the same level of PEEP in improving intra-pulmonary shunt and PaO2, without adversely affecting cardiac output.

Heart Rate↗
PubMed1978

Intermittent mandatory ventilation during anaesthesia using the Manley Servovent ventilator.

The lungs of 25 patients were ventilated with intermittent mandatory ventilation (IMV) during anaesthesia using the Manley Servovent Model MS. This ventilatory mode is especially suitable for prolonged operations in which there is no need for muscle relaxation. While incorporating the advantages of spontaneous and mechanical ventilation, it is superior to both in selected cases. The Manley Servovent Model MS ventilator is capable of delivering IMV without modification, using a single source of gas.

Adolescent↗
PubMed1978

Weaning very low birthweight infants from mechanical ventilation using intermittent mandatory ventilation and theophylline.

Two very low birthweight infants with severe clinical hyaline membrane disease requiring mechanical ventilation were dependent on slow-rate intermittent mandatory ventilation, without which they developed apnoea or hypopnoea and hypercarbia. Their ventilator dependence was apparently owing to inadequate ventilatory effort, and treatment with oral theophylline allowed easy weaning to continuous-positive airway pressure and extubation. PaCO2 was significantly lower during theophylline treatment, suggesting that the drug may have improved alveolar ventilation.

Apnea↗
PubMedDate not supplied

Advances in mechanical ventilation: high frequency ventilation.

High frequency oscillatory ventilation (HFOV) is a technique in which a small tidal volume of airway gas is vibrated by moving a piston at an extremely fast rate (15 Hz). By this technique infants are ventilated in less traumatic ways compared to the conventional mechanical ventilation (CMV). The control study performed in Japan showed the efficacy and safety of HFOV compared to CMV.

High-Frequency Ventilation↗
PubMed1976

A new versatile breathing system for CPPB. The application of PEPP during assisted and controlled ventilation or demand flow CPAP during spontaneous ventilation, with or without IMV.

A system is described which has been designed to improve the management of patients requiring CPPB. It makes use of a modified Bird Mark 7 or 8 ventilator adapted with a PEPP compensator and a new breathing circuit. This versatile unit provides several advantages over other currently available systems and makes it possible to apply PEPP during controlled and/or assisted ventilation as well as CPAP during spontaneous respiration, with IMV if another servo ventilator is included. This system has been in clinical use for 2 years and has proved to be highly reliable and efficient in both adults and children.

Adult↗