Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “VENTILATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 343 records · Page 19Linked to original sources
PubMed1999

New tools in ventilatory support: high frequency ventilation, nitric oxide, tracheal gas insufflation, non-invasive ventilation.

Protection of the lungs against ventilator-induced lung injury is becoming one of the main concerns in pediatric and neonatal intensive care. High frequency ventilation using a constant distending pressure with small variations during respiratory cycles allows adequate recruitment. High frequency oscillation is the most promising HFV mode especially in premature neonates but clinical studies are contradictory. Nitric oxide, an inhaled gas with specific pulmonary vasodilating effects, has become a powerful tool in the treatment of pulmonary arterial hypertension alone or in combination with HFO, but studies have failed to show improvement in survival in neonates as well as in children with ARDS. Tracheal gas insufflation, in addition to conventional ventilation, by washing dead space during exhalation, improves gas exchange while lowering tidal volume. It is however still experimental. Maintenance of spontaneous ventilation during conventional ventilation improves gas exchange, hemodynamic functions, mobilization, active coughing, and avoids prolonged muscle weakness. Non invasive modes of ventilation like BiPAP have certain indications in pediatrics but need to become more familiar to the pediatric intensivist.

Child↗
PubMed2004

Helmet noninvasive ventilation for weaning from mechanical ventilation.

We saw a patient who presented with carbon dioxide narcosis and acute respiratory failure due to an exacerbation of chronic obstructive pulmonary disease. We intubated and 12 hours later he had recovered consciousness and could cooperate with noninvasive ventilation, at which point we extubated and used a helmet to provide noninvasive positive-pressure ventilation in assist/control mode, and then during the ventilator-weaning process, pressure support, and finally continuous positive airway pressure. The patient had no complications from the helmet, and he was discharged from intensive care 48 hours after helmet ventilation was initiated. Helmet noninvasive ventilation is a potentially valuable ventilator-weaning method for certain patients.

Aged↗
PubMed2005

Surfactant lung lavage using asymmetric high-frequency jet ventilation followed by conventional ventilation in rabbits with meconium aspiration.

BACKGROUND: Severe impairment of lung functions in meconium aspiration syndrome (MAS) often needs the application of combined therapeutic approach. In our recent study, surfactant lung lavage during asymmetric high-frequency jet ventilation (HFJV) removed more meconium than surfactant lavage during conventional ventilation, however, after the lavage excessive CO2 elimination was observed during HFJV. OBJECTIVES: We hypothesized that the combination of asymmetric HFJV during surfactant lung lavage and conventional ventilation in the post-lavage period may be of benefit in a rabbit model of MAS. METHODS: Suspension of human meconium in saline (25 mg/ml, 4 ml/kg) was instilled into the tracheal tube of conventionally ventilated (frequency, f, 30/min, inspiration time, Ti, 50%) anesthetized rabbits to cause a respiratory failure. Animals were then lavaged (10 ml/kg in 3 portions) with diluted surfactant (Curosurf, 100 mg of phospholipids/ml) or saline during asymmetric HFJV (f, 300/min, Ti, 70%). After the lavage, animals were ventilated conventionally (f, 30/min, Ti, 50%) for next 1 hour. RESULTS: Surfactant lung lavage during asymmetric HFJV removed more meconium pigments and solids than saline with HFJV (p < 0.05 or p < 0.01, respectively). Moreover, application of asymmetric HFJV facilitated the lavage fluid removal in both groups. In the post-lavage period, improved oxygenation, lung compliance, right-to-left pulmonary shunts, and reduced ventilatory requirements were found in the surfactant group (p < 0.05), while pCO2 was kept in the normal range. CONCLUSIONS: Surfactant lung lavage by asymmetric HFJV followed by conventional ventilation is advantageous combination in rabbits with MAS and may be tested in neonatal MAS (Tab. 2, Fig. 2, Ref. 12).

Animals↗
PubMed2006

[Effects of expiratory triggering sensitivity on patient-ventilator expiratory synchrony and work of breathing in patients with chronic obstructive pulmonary disease during pressure support ventilation].

OBJECTIVE: To study the effects of expiratory triggering sensitivity (ETS) on patient-ventilator expiratory synchrony and work of breathing in chronic obstructive pulmonary disease (COPD) patients during pressure support ventilation (PSV). METHODS: A total of 31 COPD patients were ventilated in PSV mode, and measured by a pulmonary monitor. Meanwhile, the electromyogram of the diaphragm (EMG(diaph)) was obtained with electromyography. Five levels of ETS, 1%, 15%, 25%, 35%, and 50% of peak inspiratory flow (PIF), were studied in random order. Each ETS level lasted 30 minutes and all the data were recorded simultaneously for 3 minutes at the end of each period. The effects of ETS on patient-ventilator expiratory synchrony were analyzed by measuring the phase angle of expiration between the EMG(diaph) and the flow wave curve, and the effects of ETS on work of breathing by calculating total work of breathing (Wtot), work of inspiration by patients (Wi, P) and expiratory work of breathing (Wex). RESULTS: Ten patients were excluded from the study. At the 25% PIF level of ETS, patient-ventilator expiratory synchrony was the best, theta = (8 +/- 3) degrees, 16 patients - 15 degrees < or = theta < or = 15 degrees, and the amount of Wtot, Wi, p, Wex was the smallest among all the 5 levels of ETS, which was (1.86 +/- 0.53) J/L, (0.54 +/- 0.13) J/L, and (0.16 +/- 0.08) J/L respectively. When the level of ETS decreased, the occurrence of delayed termination of inspiration and the amount of Wex increased. At the level of 1% PIF, 18 patients theta > 15 degrees, and Wex was (0.48 +/- 0.10) J/L; at this level of ETS, Wi, p also increased significantly to (0.65 +/- 0.16 ) J/L. But when the level of ETS increased, the occurrence of premature termination of inspiration and the amount of Wi, p increased: at 50% PIF level of ETS, theta < - 15 degrees and Wi, p was (1.33 +/- 0.14) J/L in 19 patients. CONCLUSION: The proper adjustment of ETS during PSV improves patient-ventilator synchrony and decreases work of breathing in COPD patients.

Humans↗
PubMed1989

[Quantitative comparison of ventilator-induced work during simulated CPAP in eight demand-flow valve ventilators].

The ventilator-induced work during continuous positive airway pressure (CPAP) mode in demand-valve ventilators was evaluated by using a piston pump as a simulator for active breathing. A piston pump delivered and withdrew a stroke volume of 500 ml at rates of 10, 20 and 40 cycle.min-1 with a sinusoidal waveform. A hot-wire flowmeter and a differential pressure transducer were interposed between the pump and ventilators and their signals were fed to a microcomputer to display a pressure-volume loop. The area of the loop was divided into the four parts. Inspiratory work associated with the opening of the demand valve was represented by the area of baseline airway pressure (BPa) during inspiration. The remaining area during inspiration reflected the work done by the ventilators. Expiratory work for overcoming the flow resistance of the expiratory apparatus was represented by the area above BPa during exhalation. The fourth was the area below the baseline during exhalation. The Puritan-Bennett 7200a, the Bear 5, the Siemens Servo 900C, the Hamilton Veolar, the Bird 6400ST, the Engström Erica, the Dräger EV-A, and the CPU-1 were examined at varying CPAP and pressure support levels. Because of demand valve oscillation throughout inspiration, the inspiratory workload of the Bear 5, the Siemens Servo 900C, the Hamilton Veolar, the Bird 6400ST, and the Dräger EV-A could not be calculated. Expiratory flow-resistive work was higher in the Siemens Servo 900C and the Bird 6400ST than the others. The present system can assess the entire performance of ventilators, and may serve to compare ventilators' performance.

Evaluation Studies as Topic↗
PubMed1984

[High-frequency ventilation. Development of new ventilation systems--experimental and clinical results].

Based on the well known High Frequency Jet Ventilation (HFJV) two modified types of High Frequency Ventilation, Forced Diffusion Ventilation (FDV) and High Frequency Pulsation (HFP) have been developed. Both systems are designed to allow ventilation with very small volume portions in the upper range of HFV frequencies. In dog experiments sufficient gas exchange could be maintained during FDV up to frequencies 3000 per minute and even with an uninterrupted "continuous" jet entering the lungs on carina level. With this mode of ventilation lung could be kept in a resting position. Due to particular configuration of a pair of nozzles at the tip of a modified endotracheal catheter fresh gas is forced down the airways along the inner edges of bifurcations towards the lung periphery. At the same time stale gas leaves the lung via the remaining cross section of the airways. Thus a continuous scavanging process can be established without significant lung inflation. This mechanisms are not met during HFP. Therefore the range of frequencies achievable with this type of ventilation is significantly lower (250 to 500/min.) and "tidal volumes" are much higher. However, they are still beyond the anatomical dead space which suggest again a contribution of alternative mechanisms to gas transport. The impact of both types of HFV on gas exchange and pressure-flow conditions were studied in lung models as well as in animal experiments. FDV and HFP were also applied successfully to a group of 23 patients undergoing major lung surgery. In all patients it was possible to maintain excellent gas exchange throughout the whole surgical procedure. The exposure of the surgical field was much more quiet as compared to IPPV. Due to the small tidal volumes lung pressures can be kept much lower and gas losses via the open bronchi and lung surface are reduced dramatically.

Animals↗
PubMed1994

[New principles for mechanical ventilation of neonates and infants. High-frequency ventilation].

The aim of high frequency ventilation is to improve survival and to reduce development of chronic lung disease. The most commonly used principles of high frequency ventilation in neonates are discussed on the basis of the pathophysiology and development of lung injuries. During the year 1993, seven critically ill infants were treated with high frequency flow interruption and six with high frequency oscillation ventilation. The treatment was lifesaving, while conventional ventilation had failed. Both oxygenation and ventilation improved rapidly. In the future, our indications for high frequency ventilation will probably be extended.

Age Factors↗
PubMed1997

Comparison of alveolar ventilation, oxygenation, pressure support, and respiratory system resistance in response to noninvasive versus conventional mechanical ventilation in foals.

OBJECTIVE: To compare the efficacy of positive pressure ventilation applied through a mask versus an endotracheal tube, using anesthetized/paralyzed foals as a model for foals with hypoventilation. ANIMALS: Six 1-month-old foals. PROCEDURE: A crossover design was used to compare the physiologic response of foals to 2 ventilatory techniques, noninvasive mask mechanical ventilation (NIMV) versus endotracheal mechanical ventilation (ETMV), during a single period of anesthesia and paralysis. Arterial pH, PaO2, PaCO2, oxygen saturation, end-tidal CO2 tension, airway pressures, total respiratory system resistance, resistance across the upper airways (proximal to the midtracheal region), and positive end-expiratory pressures (PEEP) were measured. Only tidal volume (VT; 10, 12.5, and 15 ml/kg of body weight) or PEEP (7 cm of H2O) varied. RESULTS: Compared with ETMV, use of NIMV at equivalent VT resulted in PaCO2 and pH values that were significantly higher, but PaO2 was only slightly lower. Between the 2 methods, peak airway pressure was similar, but peak expiratory flow was significantly lower and total respiratory resistance higher at each VT for NIMV. Delivery of PEEP (7 cm of H2O) was slightly better for ETMV (7.1 +/- 1.3 cm of H2O) than for NIMV (5.6 +/- 0.6 cm of H2O). CONCLUSION: These data suggest that use of NIMV induces similar physiologic effects as ETMV, but the nasal cavities and mask contribute greater dead space, manifesting in hypercapnia. Increasing the VT used on a per kilogram of body weight basis, or the use of pressure-cycled ventilation might reduce hypercapnia during NIMV. CLINICAL RELEVANCE: Use of NIMV might be applicable in selected foals, such as those with hypoventilation and minimal changes in lung compliance, during weaning from endotracheal mechanical ventilation, or for short-term ventilation in weak foals.

Aging↗
PubMed1996

Patient-ventilator interaction during acute hypercapnia: pressure-support vs. proportional-assist ventilation.

The objective of this study was to compare patient-ventilator interaction during pressure-support ventilation (PSV) and proportional-assist ventilation (PAV) in the course of increased ventilatory requirement obtained by adding a dead space in 12 patients on weaning from mechanical ventilation. With PSV, the level of unloading was provided by setting the inspiratory pressure at 20 and 10 cmH2O, whereas with PAV the level of unloading was at 80 and 40% of the elastic and resistive load. Hypercapnia increased (P < 0.001) tidal swing of esophageal pressure and pressure-time product per breath at both levels of PSV and PAV. During PSV, application of dead space increased ventilation (VE) during PSV (67 +/- 4 and 145 +/- 5% during 20 and 10 cmH2O PSV, respectively, P < 0.001). This was due to a relevant increase in respiratory rate (48 +/- 4 and 103 +/- 5% during 20 and 10 cmH2O PSV, respectively, P < 0.001), whereas the increase in tidal volume (VT) played a small role (13 +/- 1 and 21 +/- 2% during 20 and 10 cmH2O PSV, respectively, P < 0.001). With PAV, the increase in VE consequent to hypercapnia (27 +/- 3 and 64 +/- 4% during 80 and 40% PAV, respectively, P < 0.001) was related to the increase in VT (32 +/- 1 and 66 +/- 2% during 80 and 40% PAV, respectively, P < 0.001), respiratory rate remaining unchanged. The increase in pressure-time product per minute and per liter consequent to acute hypercapnia and the sense of breathlessness were significantly (P < 0.001) higher during PSV than during PAV. Our data show that, after hypercapnic stimulation of the respiratory drive, the capability to increase VE through changes in VT modulated by variations in inspiratory muscle effort is preserved only during PAV; the compensatory strategy used to increase VE during PSV requires greater muscle effort and causes more pronounced patient discomfort than during PAV.

Adult↗
PubMed1988

A continuous high flow intermittent mandatory ventilation system incorporating a Downs venturi device and a modified Nuffield Series 200 ventilator.

Systems for respiratory support are becoming increasingly expensive and complex. Many systems suffer inadequacies when used for spontaneous ventilation. Some modes on newer ventilators are rarely used because of the complex controls and settings. There is no truly universal ventilator that satisfies every intensivist's wishes. CPAP/IMV is becoming accepted as the standard management of many patients with acute respiratory failure and there would be few intensive care units where CPAP/IMV is not used for part of a patient's respiratory support. We describe a cost-effective system that may be used for respiratory support in the spontaneously breathing mode. This system combines a high flow venturi, an efficient humidifier and an inexpensive reliable ventilator that can be used for adult and paediatric patients. The system, primarily for use in patients breathing spontaneously, functions well in patients requiring full ventilation.

Equipment Design↗