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Elective high-frequency oscillatory ventilation versus conventional ventilation in preterm infants with pulmonary dysfunction: systematic review and meta-analyses.

OBJECTIVES: To systematically review the evidence to determine whether the routine use of high-frequency oscillatory ventilation (HFOV) as compared with conventional ventilation (CV) is beneficial or harmful in preterm infants requiring mechanical ventilation for pulmonary failure principally due to respiratory distress syndrome. METHODS: All randomized controlled trials of elective HFOV versus CV in preterm infants <36 weeks' gestation with respiratory failure mainly attributable to respiratory distress syndrome were identified from the literature through a search of MEDLINE, EMBASE, Oxford database of Perinatal trials, and previous reviews including cross-references and abstracts. Meta-analyses using event rate ratios (ERR), event rate difference, and if significant, number needed-to-treat were calculated (95% confidence limits were used for all analyses). Two prespecified subgroup analyses were performed. RESULTS: Four published trials were included. Meta-analyses revealed the following ERR (95% confidence intervals) for HFOV versus CV: mortality at 28 to 30 days, 1.02 (0.76, 1.39); chronic lung disease (CLD) at 28 days, 0.86 (0.73, 1.01); mortality or CLD, 0.9 (0.80, 1. 01); air-leak syndromes, 1.13 (0.97, 1.33); mechanical ventilation at 28 days, 1.06 (0.84, 1.33); supplemental oxygen at discharge, 0. 59 (0.37, 0.92); intraventricular hemorrhage (IVH) all grades, 1.11 (0.95, 1.29); IVH (grades 3 or 4), 1.32 (1.01, 1.72); and periventricular leukomalacia, 1.39 (0.91, 2.13). In the subgroup of trials in which a high volume strategy (HVS) was used the ERR for CLD was 0.53 (0.36, 0.78); mortality or CLD, 0.56 (0.40, 0.77); supplemental oxygen at discharge, 0.57 (0.36, 0.92); IVH (all grades), 0.90 (0.61, 1.33); and IVH (grades 3 or 4), 0.84 (0.39, 1. 84). Results were similar to these for the trials using surfactant. One recent trial suggests that HFOV may reduce the cost of in-hospital care. CONCLUSIONS: The overall meta-analysis is dominated by the HIFI study, which was criticized for its methodology and surfactant was not used. Subsequent studies, most of which used HVS and/or surfactant, have shown benefits in measures of CLD without an increase in rates of IVH. Caution is warranted in interpreting these results because: 1) the treatment is not blinded and this could affect some outcomes; 2) except for one small trial postneonatal survival, lung function, and neurodevelopment have not been reported from HVS trials; and 3) the benefits and disadvantages have not been reported in infants born at different gestational ages or different birth weights. Importantly, results from groups experienced in the use of HFOV may not be readily generalizable.

Barotrauma↗

Ventilation tubes in secretory otitis media. A randomized, controlled study of the course, the complications, and the sequelae of ventilation tubes.

The purpose of this study has been to evaluate the use of ventilation tubes in the treatment of cases of primary secretory otitis media. Bilateral cases were selected and a tube inserted in one ear while the other ear was left intact. Adenoidectomy was performed on all children, tonsillectomy in 34% of the cases. A total of 150 children (mean age = 3.9 years) were included during the years 1976-1979 and check-ups performed every 3-6 months. The follow-up rate was 89.3%. The condition of each individual was assessed after a 5-year period, the mean period of observation was 3.2 years. The results of tympanometry and audiometry from the two types of ears were, on average, similar. Repeat operation was carried out in 17% of the cases and later otomicroscopy revealed a higher incidence of atrophy in these eardrums (p less than 0.01). A period of suppuration was noted in 25% of the ears with a ventilation tube, 2 months or more after operation; a higher incidence of tympanosclerosis was later found (p = 0.02). Twentythree per cent of the treated eardrums were characterized at the final check-up as "normal" by means of otomicroscopy, in contrast to 83% of the intact ears. The "end-result" of each ear was estimated using tympanometry, audiometry as well as otomicroscopy, and a difference in favour of the intact ears was found (p less than 0.01). A similar estimate for each child gave the result that 31% had one ear categorized as "pathological" while this was the case in both ears of 9% of the children. The children subjected to initial tonsillectomy showed a worse "end-result" (p less than 0.05). It is concluded that the use of ventilation tubes in children with primary secretory otitis media is not justified. Observation has shown that only a small proportion will require surgical treatment of the middle ear. A ventilation tube may be indicated in order to combat hearing loss, but it should be borne in mind that its use involves a high risk of complications and sequelae which may result in chronic middle ear disease.

Acoustic Impedance Tests↗

[Role of noninvasiveness ventilation in the weaning phase of mechanical ventilation].

During the last decade, noninvasive ventilation has proved to be a valuable alternative to endotracheal intubation in many patients with acute respiratory failure, allowing a reduction in morbidity, mortality and length of intensive care and hospital stay compared to conventional mechanical ventilation. Recent data from clinical studies suggest that these beneficial effects could also be extended to the weaning phase of mechanical ventilation, by reducing, in some patients at any rate, its duration and complication rate. The present paper focuses on some of these promising new aspects of noninvasive ventilation and attempts to define the possible indications and limits of this technique in the context of weaning.

Humans↗

[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↗

[A case of "ventilation difficulty-intubation difficulty" solved with transtracheal jet ventilation].

A 56-year-old man recovering from a glossectomy and radical neck dissection presented severe oral bleeding, tracheal deviation with an asphyxiating hematoma and cyanosis. When 2 attempts at orotracheal intubation with the patient awake failed, transtracheal jet ventilation was used temporarily until a definitive airway could be established. Transtracheal jet ventilation is highly useful for managing an airway and maintaining gas exchange in life-threatening situations in which intubation and ventilation has become impossible, yet it is rarely used for that purpose. An easy, fast procedure that has not been widely used in Spain, this technique provides effective ventilation and oxygen while a definitive resolution of the emergency is sought.

Equipment Design↗

[VENISE: Non-invasive ventilation during mechanical ventilation weaning in chronic respiratory failure patients. A prospective randomised controlled and multicenter trial].

INTRODUCTION: The clinical efficacy of non-invasive ventilation (NIV) has now been demonstrated in the management of acute-on-chronic respiratory failure (ACRF) in various etiologies. Endotracheal mechanical ventilation (ETMV) can lead to numerous complications and weaning difficulties increasing the risk of prolonged ETMV, morbidity and mortality as well as excess cost of intensive care. Therefore, it could be useful to consider NIV for delivering effective ventilatory support to reduce the length of ETMV in ACRF patients who are still not capable of maintaining spontaneous breathing. From the interesting but discordant results of two recent randomised controlled trials, a working group from the Société de Réanimation de Langue Française (SRLF) decided to perform a new prospective randomised controlled multicenter trial. The aim of the study will be to assess the usefulness of NIV as an extubation and weaning technique in ventilated ACRF patients. METHODS: The methodology used will compare three parallel weaning strategies in ACRF patients considered difficult to wean: invasive conventional weaning (group A), extubation relayed by nasal oxygentherapy (group B), and extubation relayed by NIV (group C). Based on the main end-point defined as the weaning success rate, 208 patients from 17 investigator centers are planned to be included. Results of the study will also allow to assess the respective impact of the three weaning strategies on the length of ETMV and weaning, the mechanical ventilation-related morbidity, the patients lengths of stay and mortality. EXPECTED RESULTS: Results of the VENISE trial should permit to improve the management of the difficult to wean ACRF patients and thus contribute to more precisely define the place of NIV in the weaning and prevention of re-intubation strategies in these patients.

Chronic Disease↗

Correction of error in respiratory resistance measurements made with the flow-interruption technique during mechanical ventilation: evaluation of the puritan bennett 7200 and 840 ventilators.

BACKGROUND: Calculation of total inspiratory resistance (Rtot) for patients on ventilatory support is typically based on measurement of airflow velocity and airway opening pressure during end-inspiratory occlusion by the inspiratory valve in the ventilator. Systematic error is introduced into Rtot measurements because the inspiratory valve closes over a period of time (not instantaneously, so gas continues to flow into the circuit while the valve is shutting) and because the circuit tubing is a distensible compartment between the occluding valve and the respiratory system. The Rtot-measurement error can be minimized with a rapidly-shutting occlusion valve positioned at the airway opening, or, alternatively, by mathematical correction that accounts for the valve-closure period and circuit tubing characteristics. METHODS: In a bench study we measured Rtot with the Puritan Bennett 7200 and 840 ventilators (using the inspiratory valves that are built into those ventilators) and compared those measurements to measurements made with a rapidly-shutting valve at the airway opening. We deemed the rapid-occlusion-valve measurements the best available (benchmark) values. We also studied the closure characteristics of the ventilators' inspiratory occlusion valves and created equations for mathematical correction of Rtot values measured with those valves. RESULTS: Compared to the benchmark measurements, the measurements from the Puritan Bennett 7200 averaged 23.2% relative error and 2.6 cm H2O/L/s absolute error. Measurements from the Puritan Bennett 840 averaged 7.3% relative error and 1.0 cm H2O/L/s absolute error. Mathematical correction for the circuit tubing and valve-closure time reduced the average relative and absolute error to 3.0% and 0.4 cm H2O/L/s, respectively, for the Puritan Bennett 7200, and to 4.5% and 0.3 cm H2O/L/s, respectively, for the Puritan Bennett 840. CONCLUSIONS: The Puritan Bennett 840 measures Rtot more accurately than the Puritan Bennett 7200. Our equations to mathematically correct Rtot measurements made with the PB7200 and PB840 are useful in settings where very accurate Rtot measurements are necessary.

Airway Resistance↗

Noninvasive positive-pressure ventilation and ventilator-associated pneumonia.

There is much interest in the use of noninvasive positive-pressure ventilation (NPPV) to prevent intubation and afford a survival benefit for patients. The risk of pneumonia in patients receiving NPPV has been reported in 12 studies. Compared to patients receiving invasive mechanical ventilation (4 studies), the pneumonia rate is lower with the use of NPPV (relative risk [RR] 0.15, 95% confidence interval [CI] 0.04 to 0.58, p = 0.006). Compared to patients assigned to invasive mechanical ventilation (3 studies), in which some of the patients assigned to NPPV did not respond and were eventually intubated, there was also a benefit for the use of NPPV (RR 0.24, 95% CI 0.08 to 0.73, p = 0.01). In studies in which patients assigned to NPPV were compared to patients assigned to standard therapy (5 studies), in which some of the patients in each group were eventually intubated, there was benefit shown for the use of NPPV (RR 0.56, 95% CI 0.31 to 1.02, p = 0.06). When this meta-analysis is repeated without the results of the negative study for NPPV (extubation failure), there is a stronger benefit in support of NPPV to decrease the risk of pneumonia in the remaining 4 studies (RR 0.38, 95% CI 0.20 to 0.73, p = 0.003). A meta-analysis combining the results from the 12 studies reviewed shows a strong benefit for NPPV (RR 0.31, 95% CI 0.16 to 0.57, p = 0.0002). One randomized controlled trial of continuous positive airway pressure compared with standard treatment in patients who developed acute hypoxemia after elective major abdominal surgery reported a lower rate of pneumonia with continuous positive airway pressure (2% vs 10%, RR 0.19, 95% CI 0.04 to 0.88, p = 0.02). In patients who are appropriate candidates for NPPV or continuous positive airway pressure, the available evidence suggests a benefit in terms of a lower risk of pneumonia. Perhaps "endotracheal-tube-associated pneumonia" is a better term than "ventilator-associated pneumonia."

Cohort Studies↗

[Can ventilation based on the principle of the iron lung act today as a substitute for or an alternative method to conventional forms of ventilation?].

A plastic lung working on the same principles as an iron lung has been developed at the Medical School in Hannover. Functional and practical tests were performed in a representative group of patients. Respirators support following the principles of an iron lung may be provided as a supplement or an alternative to existing artificial respirator therapy. The modern artificial respirators are superior to the plastic lung, which however, has advantages for particular indications: Respiratory therapy performed in a plastic lung is well tolerated by the patients. It requires specific skills which can easily be learned by the medical staff. Routine use certainly cannot be instituted before further technical improvement has been achieved; in particular the noise level should be reduced. The plastic lung is suitable for short-term ventilation (2-10 h); in view of the restricted nursing procedures possible, prolonged artificial respiration cannot be recommended. In conclusion, immediate postoperative ventilation is the area of application for the plastic lung. Several advantages are known: the endotracheal tube can be removed, there is no indication for sedative drugs, cardiac function and organ blood flow are positively influenced, mucolysis and lung expansion are adequate. A patient whose spontaneous respiratory activity is borderline benefits from short-term therapy, which can be repeated as necessary. Protracted artificial ventilation can be avoided. The gradual process of weaning from the ventilator following prolonged artificial respiration is facilitated by the use of a plastic lung. Plastic lung therapy is superior to other common methods of treating persistent atelectasis, because its mucolytic effects lead to expansion of the atelectatic lobe or segment.(ABSTRACT TRUNCATED AT 250 WORDS)

Equipment Design↗

Increase of the oxygenation and decrease of the intrapulmonary peak pressure at constant mean airway pressure using high-frequency jet ventilation in adult rabbits with lavage-induced severe respiratory distress syndrome compared to conventional mechanical ventilation.

Reports are contradictory about the value of high-frequency jet ventilation (HFJV) in the treatment of respiratory distress syndrome (RDS) [10, 11, 18 - 1, 2, 22, 25]. In a preliminary study on rabbits with healthy as well as surfactant deficient lungs, caused by lung lavage, at a constant mean airway pressure (MAP) and 20% inspiration time, the influence of the jet ventilation frequencies of 1, 3, 5, 10, 15 and 20 Hz (cycles per second) on the pressure oscillations along the airways as well as on blood gas and cardiac parameters were investigated. It was presumed that the breathing level, e.g. functional residual capacity plus 50% of the tidal volume is the same at constant MAP. The results during HFJV are compared to those of conventional mechanical ventilation (CMV). With increasing frequency the peak airway pressure (PAP) clearly decreased on both groups, while the self controlled positive end-expiratory pressure (AUTO-PEEP) increased. That means, the amplitude of the pressure oscillations became smaller and smaller, indicating that the danger of mechanical lesions might be reduced by this mode of ventilation. The arterial oxygenation (PaO2) increased with frequency. A threefold higher PaO2 could be obtained at 10 Hz in the animals with RDS lungs. The arterial carbon dioxide tension (PaCO2) increased nearly linear with the frequency in both groups. The inverse course of the arterial pH showed that it is possible to obtain at lower frequencies a respiratory alkalosis and at higher frequencies an acidosis. Optimal gas exchange could be obtained at about 10 Hz. Decreasing cardiac output with increasing frequency showed a good correlation to the pH in both groups. The effect was more influenced by the heart frequency than by the stroke volume especially in the RDS-group.

Animals↗

[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↗

[Differential artificial lung ventilation as an alternative to single lung ventilation in thoracic surgery].

The study was undertaken to develop and introduce a lung artificial ventilation (LAV) procedure that levels the pathophysiological changes associated with collapse of the lung operated on, which is based on comparison of the impact of one-lung and differential LAV on gas exchange and hemodynamics. It was found that under differential ventilation, ventilation-perfusion ratios became normal, pulmonary pressure dropped, resistance in all regions of the lung microcirculatory bed decreased, the volume of intrapulmonary shunting became smaller. Concomitantly, there were reductions in right cardiac preload and fluid filtration into the both parts of the extravascular lung space. This all shows that there is a significant increase in the efficiency of intrapulmonary gas exchange. Thus, differential ventilation is the most advisable alternative to collapse of the independent lung in thoracic surgery hemodynamics. It is the method of choice in pulmonary hypertension, right ventricular failure, oxygenation function of the lung.

Adult↗

[Home mechanical ventilation with nasal intermittent positive pressure ventilation for a boy with congenital central hypoventilation syndrome].

We report a 4-year-old boy with congenital central hypoventilation syndrome (CCHS) successfully treated with home mechanical ventilation with nasal intermittent positive pressure ventilation (NIPPV) during sleep hours. He had had frequent severe apneic attacks from the neonatal period. At 8 months, he was treated with positive pressure ventilation following a tracheostomy. At 4 year and 2 months, NIPPV was attempted because of recurrent respiratory tract infections and cor pulmonale. The tracheostomy was successfully abandoned 6 months later. Adequate ventilation has been maintained for more than 3 years without troubles. NIPPV is an effective and non-invasive treatment of CCHS that it significantly improves the quality of life during daytime.

Child, Preschool↗

High-frequency mechanical ventilation principles and practices in the era of lung-protective ventilation strategies.

The term high-frequency ventilation is used to describe a heterogeneous group of ventilation modes that are characterized by high respiratory frequencies and low tidal volumes. The increasing understanding of the pathogenesis of VILI, including concepts such as volutrauma and atelectrauma, has led to a renewed interest in the role of HFV in lung-protective ventilation strategies. Inherent to many modes of HFV are low tidal volumes and small pressure swings during the respiratory cycle, which allow for higher mean airway pressures than those safely achieved with CMV. This has the potential to reduce lung injury by limiting volutrauma, whereas maintaining bigger lung volumes at end-expiration may reduce atelectrauma. Of the various forms of HFV, HFO is the only mode with an active expiration phase. This characteristic, combined with superior gas conditioning, may make HFO a promising ventilatory strategy for adults. Although a significant amount of data exists in the literature to support the application of HFO in infants and children who have acute respiratory failure, clinical data on the use of HFO in adults is only now emerging. Early studies of applying HFO in ARDS patients have demonstrated its safety and benefit in terms of oxygenation. Additionally, limited data exist on the comparison between HFO and CMV in this patient population; however, encouraging preliminary results have been reported. The optimum strategy for the application of HFV, including the timing of HFV initiation, remains unclear.

Barotrauma↗

Chest physiotherapy for preventing morbidity in babies being extubated from mechanical ventilation.

BACKGROUND: This section is under preparation and will be included in the next issue. OBJECTIVES: To assess the effects of active chest physiotherapy on babies being extubated from mechanical ventilation for neonatal respiratory failure. SEARCH STRATEGY: The standard search strategy for the Neonatal Review Group was used as outlined in the Cochrane Handbook in the Cochrane Library. SELECTION CRITERIA: All trials utilising random or quasi-random patient allocation, in which active chest physiotherapy was compared with non-active techniques (eg positioning and suction alone) or no intervention in the periextubation period. The methodological quality of each trial was assessed by two independent authors. DATA COLLECTION AND ANALYSIS: Data were extracted independently by two authors. The data were analysed from 3 trials. Subgroup analysis was performed on different treatment frequencies. MAIN RESULTS: In this review of 3 small trials, 2 of which were carried out 10 & 20 years ago, no clear benefit of periextubation active chest physiotherapy can be seen. Active chest physiotherapy did not significantly reduce the rate of postextubation lobar collapse (RR 0.69;0.33,1.45), though a reduction in the use of reintubation was shown in the overall analysis (RR 0.24;0.08,0.75). Subgroup analysis of different treatment frequencies showed the same effect with more frequent treatment (1 & 2 hourly) but showed a trend to increased lobar collapse, and no reduction in the use of reintubation, with less frequent treatment (4 hourly). There is insufficient information to assess other important short and long term outcomes, including adverse effects. REVIEWER'S CONCLUSIONS: The results of this review do not allow development of clear guidelines for clinical practice. Caution is required when interpreting the possible positive effects of chest physiotherapy of a reduction in the use of reintubation and the trend for decreased post-extubation atelectasis as the numbers of babies studied are small, the results are not consistent across trials, data on safety are insufficient, and applicability to current practice may be limited.

Humans↗

Liquid ventilation: an alternative ventilation strategy for management of neonatal respiratory distress.

Perfluorochemical (PFC) liquids have great potential for biomedical use and the support of respiration. Currently, there are several commercially available PFC fluids which meet the physiochemical property requirements as well as purity specifications necessary to perform many of the discussed biomedical applications. Moreover, state-of-the-art fluorine chemistry should enable production of new PFC liquids uniquely sculptured relative to the proposed specific application (ie. vehicle for pulmonary delivery of drugs, a diluent for pulmonary lavage, a medium for respiratory gas exchange). In addition to PFC fluid requirements, there have been several techniques reported for liquid assisted ventilation. These methods include total liquid ventilation, liquid lavage, and partial liquid ventilation. The efficacy of these various techniques is under extensive investigation with respect to specific types of lung dysfunction. Liquid ventilation (LV) techniques have the potential to treat lung disease with less risk of barotrauma and provide the means for direct and uniform delivery of pulmonary agents to injured or dysfunctional sites in the lung. For LV to assume a role in clinical medicine it must be shown to be safe and effective with respect to other therapies or in combination with current therapies. Although the use of LV in animal and initial clinical studies has been impressive to date, better documentation of efficacy in human disease will be required. Further controlled multi-center clinical trials are warranted and are currently in progress.

Animals↗

Comparison of the effectiveness of manual and ventilator hyperinflation at different levels of positive end-expiratory pressure in artificially ventilated and intubated intensive care patients.

BACKGROUND: Manual hyperinflation (MHI) and ventilator hyperinflation (VHI) are two methods of recruitment maneuvers used in ventilated patients to improve lung compliance and secretion mobilization. The use of VHI may minimize the adverse effects of disconnection from the ventilator, but it is uncertain whether high levels of positive end-expiratory pressure (PEEP) would decrease the peak expiratory flow rate (PEFR) and consequently affect secretion clearance. OBJECTIVES: The aim of this study was to compare the effectiveness of MHI and VHI in terms of clearing pulmonary secretions (sputum wet weight and PEFR), improving static respiratory system compliance and oxygenation (arterial oxygen tension/fraction of inspired oxygen), and altering mean arterial pressure, heart rate, and carbon dioxide output at different levels of PEEP. METHODS: This was a randomized crossover study involving 14 general intensive care patients who were intubated and mechanically ventilated. RESULTS: Sputum production was similar in both techniques and levels of PEEP. There were no differences in improvement in oxygenation and static respiratory system compliance between MHI and VHI. However, VHI increased Cst significantly at 30 minutes posttreatment (P = .012), and a significant difference was observed between levels 5 and 7.5 cmH(2)O (P = .02) of PEEP for MHI. MHI generated higher PEFR than VHI (P < .05). No adverse change in heart rate or mean arterial pressure was observed during either technique; however, VCO(2) was significantly different for techniques (P = .045) and over time (P = .05). CONCLUSION: The VHI technique seems to promote greater improvements in respiratory mechanics with less metabolic disturbance compared with MHI. Other variables such as sputum production, hemodynamics, and oxygenation were affected similarly by both techniques.

Adult↗

Comparison of ventilation and chest compression performance by bystanders using the Impact Model 730 ventilator and a conventional bag valve with mask in a model of adult cardiopulmonary arrest.

"Bystanders" or lay persons are typically the first caregivers to attend to a victim of out-of-hospital cardiopulmonary arrest. Astronaut crew medical officers (CMO) play a similar role to bystanders aboard the International Space Station (ISS). Studies have demonstrated the importance of bystander cardiopulmonary resuscitation (BCPR) for patient survival before the arrival of emergency medical care. Recent apprehension from bystanders about the threat of contracting communicable diseases during BCPR, however, has led to the consideration of other ventilation systems such as the bag-valve mask (BVM) and automatic transport ventilators (ATV). BVM use is called for during CPR aboard the ISS. This study evaluated the ventilation and compression performance of 40 basic CPR-trained bystanders using either a BVM (adult-sized self-inflating bag with face mask) or an ATV (Model 730 ventilator (M730), Impact Instrumentation, Inc., West Caldwell, NJ). Each two-bystander team gave BCPR to a simulated cardiopulmonary arrest victim using the 2-breath/15-compression cycle for 4 min and then switched roles for another 4-min interval. Compared to BVM use, the M730 led to significantly (p<0.05) lower number of breaths, smaller tidal volumes, airway flows, airway pressures, volume of gas entering the stomach per breath and chest compressions for the 4-min period. The M730 also enabled a bystander to meet the recommendation of 4-breath and compression cycles per minute as per Guidelines 2000. Lastly, ease-of-use scores were significantly higher for the M730 compared to the BVM. Overall, the data suggest that the M730 improves the quality of performance for a bystander performing BCPR.

Cardiopulmonary Resuscitation↗