PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Positive-Pressure Respiration”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1975

[Justification, methods and indications for positive-pressure respiration in controlled and spontaneous ventilation in lesional pulmonary edeman].

Proposed since 1938 as a treatment for pulmonary edema, continuous positive pressure ventilation (PPP) still called teleexpiratory positive pressure in France (PPTE) and "Positive End Expiratory Pressure" (PEEP) or even "Continuous Pressure Breathing" (CPPB) in Anglo-Saxon countries, has taken a place in the first line of therapy in refractory hypoxia and particulary when the latter originate from lesional pulmonary edema. The aim of PPP is to open up the alveolar territories by calling on their elastic properties, to fight against micro-atelectasis and bronchial collapse, to diminish the closing volume, to increase the FRC, thereby improve VA/Qc, decrease Qs/Qt and increase PaO2. Furthermore, in the particular case of pulmonary edema, PPP acts against the hydrostatic pressure by increasing the external component of the transmural pressure and by evening out pulmonary capillary blood flow.

Carbon Dioxide↗
PubMed2026

Respiratory effects of recruitment maneuvers according to lung recruitability assessed by electrical impedance tomography in patients with acute respiratory distress syndrome.

Recruitment maneuvers (RM) can improve oxygenation in patients with acute respiratory distress syndrome (ARDS), but their physiological effects depend on lung recruitability. This secondary analysis of a randomized controlled trial (RCT) evaluated oxygenation, respiratory mechanics, regional ventilation, and cardiorespiratory adverse events responses to a RM followed by electrical impedance tomography (EIT)-guided PEEP titration, using EIT to assess lung recruitability. In this study, fifty patients with moderate-to-severe ARDS underwent a stepwise RM followed by individualized PEEP titration guided by EIT. Lung recruitability was determined using the collapse index at PEEP 6 cmH&#x2082;O (CLPEEP6), defined as the proportion of collapsed lung at this PEEP level. Patients were classified into high- and low-recruitability groups based on median CLPEEP6 values. Oxygenation (PaO&#x2082;/FiO&#x2082;), static compliance (Cstat), driving pressure (Pdriv), regional ventilation distribution, and cardiorespiratory adverse events were compared before and after RM, during subsequent individualized EIT-guided PEEP titration. In patients with high recruitability (CLPEEP6&#x2009;>&#x2009;12.5), the PaO&#x2082;/FiO&#x2082; ratio and Cstat increased significantly after RM (PaO&#x2082;/FiO&#x2082;: 100.8&#x2009;&#xb1;&#x2009;30.3 vs. 125.4&#x2009;&#xb1;&#x2009;38.3&#xa0;mmHg, p&#x2009;<&#x2009;0.05; Cstat: 21.5&#x2009;&#xb1;&#x2009;5.8 vs. 28.0&#x2009;&#xb1;&#x2009;7.0&#xa0;mL/cmH&#x2082;O, p&#x2009;<&#x2009;0.001), Pdriv decreased (19.1&#x2009;&#xb1;&#x2009;3.5 vs. 15.6&#x2009;&#xb1;&#x2009;3.2 cmH&#x2082;O, p&#x2009;<&#x2009;0.001). EIT demonstrated a posterior redistribution of ventilation after RM. In contrast, patients with low recruitability (CLPEEP6&#x2009;&#x2264;&#x2009;12.5) showed no significant mechanical or oxygenation improvement and transient hypotension, arrhythmia, and desaturation appeared numerically more common in this group. No barotrauma or cardiac arrest occurred, and ICU mortality was similar between groups. A strategy combining a RM with subsequent individualized EIT-guided PEEP titration was associated with improved oxygenation and lung mechanics in patients with high lung recruitability, whereas patients with low recruitability showed limited physiological benefit, with cardiorespiratory adverse events appearing numerically more frequent. The EIT-derived CLPEEP6 index represents a feasible and clinically applicable https://clinicaltrials.gov/study/NCT06733168.

Humans↗
PubMed1977

The effect of C.P.A.P. upon pulmonary reserve and cardiac output under increased abdominal pressure.

The cardiopulmonary effects of CPAP under conditions of increased intra-abdominal pressure were studied using the rabbit as an experimental model. Central venous pressure and cardiac output were reduced when the intra-abdominal pressure was increased. Addition of CPAP caused a further reduction in C.V.P. and C.O. Despite these reductions CPAP significantly improved arterial PaO2 without significant effects on pH and PaCO2. The use of CPAP in conditions associated with pulmonary dysfunction secondary to increased intraabdominal pressure may be a definite therapeutic modality.

Abdomen↗
PubMed1976

Pulmonary function in premature lambs during the first few hours of life.

This study establishes the mean values, variations, and trend of pulmonary function during the first few hours of life in premature lambs. Measurements of intraesophaheal and tracheal pressure, air flow, tidal volume, and functional residual capacity enabled calculations of lung compliance, specific lung compliance, and inspiratory and expiratory resistance of the lungs. Arterial carbon dioxide tension and pH were maintained within a physiologic range. Mean arterial oxygen tension (PO2) at elevated inspired oxygen tension, varied in the individual animals from 51 to 185 mm Hg at an inspired oxygen concentration of 46 to 71%. It was found that the lungs of premature lambs delivered by cesarean section were mechanically unstable; the lambs were all ineffectual at breathing and required some form of mechanical ventilation. During the first 6 hours of postnatal life the lungs of premature lambs are characterized by a wide range of mechanical values and blood gas tensions.

Animals↗
PubMedDate not supplied

Application of the Starling resistor concept to the lungs during CPPV.

The application of the Starling resistor concept of the lungs during continuous positive pressure ventilation (CPPV) was evaluated. Ventilation and hemodynamics were studied in eight anesthetized and paralyzed dogs before and during the use of CPPV. CPPV resulted in an increase in transpulmonary pressure and functional residual capacity (FRC), and a decrease in arterial pH and mixed venous oxygen tension (PvO2). Cardica index decreased 32% (p less than 0.01) and stroke volume 51% (p less than 0.01). Neither right nor left transmural pressures changed but pulmonary vascular resistance increased 189% (p less than 0.01). This study supports the concept that the pulmonary vasculature behaves as a Starling resistor during the use of CPPV. The increase in pulmonary vascular resistance must be considered when transpulmonary pressure is raised by CPPV.

Animals↗
PubMed1977

Further studies of rimiterol and salbutamol administered by intermittent positive-pressure ventilation, and an important observation on the technique of using the Bennett ventilator.

1. Using the same technique of administering drugs by intermittent positive-pressure ventilation as used in previous studies a source of contamination of solutions nebulized was discovered. This was rectified by using a new ventilator and completely separate patient circuits for each solution nebulized. 2 Salbutamol 0.5% and 0.25% solutions achieved the same degree of bronchodilatation, but there was a significantly greater increase in heart rate produced by salbutamol 0.5%. 3 Rimiterol 0.5% and salbutamol 0.25% produced similar peak mean improvements in FEV and also induced the same degree of tachycardia, but the duration of these effects were significantly shorter in the case of rimiterol. 4 The sustained degree of bronchodilatation achieved by salbutamol 0.25% could not be mirrored by giving two doses of rimiterol 0.5%, the second dose 2 h after the first. 5 Rimiterol 0.5% induced a degree of tachycardia which was similar in peak effect to that observed after salbutamol 0.25%. However, in the controls the second dose of rimiterol, given 2 h after the first, was responsible for only a small increase in heart rate which was not significantly different than that after saline in the other three treatment groups.

Adult↗
PubMed1977

Effect of continuous positive airway pressure breathing on cardiorespiratory function in infants with respiratory distress syndrome.

A method of investigating the cardiorespiratory responses to continuous positive airway presslre (CPAP) in infants with respiratory distress syndrome is described. All measurements were made immediately before and within five minutes of application or any change in level of CPAP. Ventilation was derived from a pneumotachograph and dynamic compliance calculated. We have also measured arterial pH, oxygen and carbon dioxide tensions, arterial blood pressure and central venous pressure. Arterial oxygen tension increased in association with a decrease in the alveolar-arterial oxygen gradient. No consistent changes occurred in pH or carbon dioxide tension. Heart rate and mean arterial blood pressure remained the same but the arterial pulse pressure narrowed and the increase in central venous pressure averaged 17% of the applied airway pressure. There were less variations in both tidal volumes and instantaneous respiratory rates with CPAP compared with spontaneous breathing without CPAP. The respiratory rate decreased, but there were no consistent changes in tidal volume, resulting in a lesser reduction of minute ventilation. Dynamic compliance decreased on CPAP. With correct use of CPAP, and improvement in oxygenation generally occurs without obvious adverse cardiorespiratory effects. CPAP must nevertheless be used cautiously and in conjunction with close monitoring; because when the appropriate pressures are exceeded, it is possible that both circulatory and ventilatory function might be severely compromised.

Blood Pressure↗
PubMed2026

Impact of real-time respiratory function monitoring on neonatal mask ventilation training: a multicentre simulation-based crossover study.

OBJECTIVE: To evaluate whether visibility of respiratory function monitor (RFM) feedback improves mask ventilation performance and influences subsequent ventilation performance during neonatal resuscitation training. DESIGN: multicentre randomised crossover simulation study. PARTICIPANTS: Healthcare professionals involved in neonatal resuscitation training across participating centres. INTERVENTION: Participants performed positive pressure ventilation (PPV) on both term and premature manikins under two conditions: with visible RFM feedback and with the display masked. The order of feedback visibility was randomised. Each participant completed ventilation assessments in both conditions. MAIN OUTCOME MEASURES: Primary outcomes were expired tidal volume (Vte) and mask leak (%). The proportion of breaths within the target Vte range (4-8&#x2009;mL/kg) was calculated as a performance indicator. Secondary outcomes included variability in Vte and mask leak to assess ventilation stability between conditions. RESULTS: Visible RFM feedback was associated with lower mask leak and improved ventilation stability in the preterm manikin and with tidal volumes entering the target range in the term manikin. Participants initially ventilated with visible feedback maintained performance after feedback removal, suggesting a carry-over learning effect. CONCLUSION: In this multicentre crossover simulation study, visible RFM feedback was associated with changes in mask ventilation performance and evidence of a carry-over learning effect following feedback removal. Real-time visibility of respiratory parameters may strengthen neonatal resuscitation training.

Humans↗
PubMed1976

Effects of continuous positive-pressure ventilation in experimental pulmonary edema.

We compared the effects of continuous positive-pressure ventilation (CPPV), using 10 cmH2O positive end-expiratory pressure (PEEP), with intermittent positive-pressure ventilation (IPPV), on pulmonary extravascular water volume (PEWV) and lung function in dogs with pulmonary edema caused by elevated left atrial pressure and decreased colloid osmotic pressure. The PEWV was measured by gravimetric and double-isotope indicator dilution methods. Animals with high (22-33 mmHg), moderately elevated (12-20 mmHg), and normal (3-11 mmHg) left atrial pressures (Pla) were studied. The PEWV by both methods was significantly increased in the high and moderate Pla groups, the former greater than the latter (P less than 0.05). There was no difference in the PEWV between animals receiving CPPV and those receiving IPPV in both the high and moderately elevated Pla groups. However, in animals with high Pla, the Pao2 was significantly better maintained and the inflation pressure required to deliver a tidal volume of 12 ml/kg was significantly less with the use of CPPV than with IPPV. We conclude that in pulmonary edema associated with high Pla, PEEP does not reduce PEWV but does improve pulmonary function.

Animals↗
PubMed1976

Nasal continuous positive airway pressure. Improvement in arterial oxygenation in hyaline membrane disease.

Continuous positive airway pressure (CPAP) was employed using nasal prongs in 30 neonates with hyaline membrane disease (HMD). There was a significant improvement in mean PaO2 (from 47 to 80 mmHg;p less than 0.001) with no significant change in PaCO2 or pH within a mean 36 min of therapy. Use of the technique allowed reduction of FiO2 to less than 0.60 in less than 20 h in 18 infants. Infants treated within 24 h of birth had significantly greater improvements in PaO2. Complications were infrequent and only 3 of 30 babies developed a pneumothorax while on nasal CPAP. Only 1 of the 23 survivors required mechanical ventilation in addition to nasal CPAP.

Carbon Dioxide↗
PubMed1976

[General anesthesia and bronchoscopy].

High frequency, positive pressure ventilation during anesthesia for bronchoscopy, uses the intermittent delivery of oxygen and an anesthetic gas mixture thus avoiding the risks of hypoxia, retention of carbon dioxide and concomitant acidosis. This technique may be used with low pressures in the airways (8 to 10 cm of water during insufflation).

Anesthesia, Inhalation↗
PubMedDate not supplied

The effect of different endotracheal suction procedures on arterial blood gases in a controlled experimental model.

In an anesthetized hypoxemic animal model, 15 seconds of endotracheal suctioning, using a suction pressure of --170 mm. Hg and endotracheal tube to suction catheter ratio of 1.87 to 1, produced a 13 mm. Hg fall in arterial oxygen tension. Oxygen tension did not return to control level even at 5 minutes after suctioning. Giving 100 per cent oxygen before suctioning prevented suction-induced hypoxemia during and immediately after suctioning, but at 5 minutes after suctioning, oxygen tension fell below control levels. Mechanical lung hyperinflation with room air after suctioning quickly raised arterial oxygen tension above control levels. When mechanical ventilation using 100 per cent oxygen was maintained before, during, and after the suction procedure, arterial oxygen tension remained elevated at all times.

Animals↗
PubMed1976

"Aspiration disease".

Aspiration disease, a term used to define both an acute and chronic form of a disease entity, is described. Etiological factors, pathophysiology and therapy are discussed with emphasis on aspiration of gastric juice. A brief mention of a small clinical experience is included.

Acute Disease↗