Effects Of Negative Pressure Ventilation Research Articles

Effects of Negative Pressure Ventilation on Lung Volume and Airflow in Drug-Induced Sleep Endoscopy

Effects of Negative Pressure Ventilation on Lung Volume and Airflow in Drug-Induced Sleep Endoscopy

0487 The effect of negative pressure ventilation on airflow in obstructive sleep apnea subjects undergoing drug induced sleep endoscopy

Abstract Introduction Drug induced sleep endoscopy (DISE) is used to visually characterize pharyngeal airway collapse in obstructive sleep apnea (OSA) to help determine appropriate patients for OSA surgery. The procedure has grown in complexity with the addition of airflow recording and continuous positive airway pressure (CPAP) titration to obtain additional measures of airway collapsibility. Lung volume can also influence airway collapse in OSA but is not evaluated as part of routine DISE. The purpose of this study is to characterize the relationship between changes in lung volume and upper airway collapse during DISE to gain further insight into factors contributing to airway collapse and their potential roles in influencing surgical decision making. Methods This study is an ongoing IRB approved prospective clinical trial assessing the effects of negative pressure ventilation on airway collapse during DISE. Enrolled patients first undergo DISE evaluation per clinical routine including a CPAP titration. CPAP is then held at a level where patients exhibit stable flow limitation. A negative pressure ventilator shell is placed over the torso of the body and negative pressures of up to -25cmH2O are applied to expand the chest and increase lung volume. Changes to nasal airflow and tidal volume are evaluated. The negative pressure ventilator is then released and changes to airflow back to baseline are recorded. Results Between 6/30/2022 and 11/30/2022, 5 patients completed the study. There were 4 men and 1 woman with an average age of 60 years, BMI of 26.67kg/m2, and apnea-hypopnea index (AHI) of 44.44 events/hr. Average peak inspiratory flow increased from 8.38L/min to 13.78L/min and average tidal volumes increased from 155mL to 269mL on negative pressure ventilation. Conclusion Increases in lung volume from negative pressure ventilation during DISE can improve airflow and tidal volume suggesting that changes in lung volume can influence the severity of upper airway collapse. Further study to better characterize this relationship can help add additional diagnostic information regarding airway collapse characteristics to provide better informed surgical decisions and develop new interventions. Support (if any) Supported by the National Center for Advancing Translational Sciences (NCATS) of the National Institutes of Health (NIH) under Award Numbers UL1TR002378 and KL2TR002381

A pilot study of short-term hemodynamic effects of negative pressure ventilation in chronic obstructive pulmonary disease assessed using electrical cardiometry.

BackgroundPulmonary rehabilitation combined with negative pressure ventilation (NPV) demonstrated benefits in patients with chronic obstructive pulmonary disease (COPD). The effect of NPV remains unknown. This study aims to clarify the short‐term response of the hemodynamic outcome of NPV in patients with COPD undergoing pulmonary rehabilitation program by electrical cardiometry.MethodsThis is an observational retrospective study of COPD patients who had been treated in a pulmonary rehabilitation unit with NPV between January 2018 and December 2019 that were enrolled to analyze the hemodynamic outcomes.ResultsThirty patients with COPD that were undergoing a pulmonary rehabilitation program and were regularly receiving NPV were enrolled. Cardiac output (p < .001) and heart rate (p < .001) showed a significant decrease after NPV. Stroke volume did not demonstrate significant change (p = .15). There was a significant decrease in thoracic fluid content (p = .016) and a significant increase in stroke volume variation (p = .038) systemic vascular resistance (p < .001) and left ventricular ejection time (p < .001). Other hemodynamic parameters were all comparable before and after NPV.ConclusionsNegative pressure ventilation demonstrated an impact on hemodynamics in patients with chronic obstructive pulmonary disease undergoing pulmonary rehabilitation. Electrical cardiometry is a feasible method of determining the hemodynamic effects of negative pressure ventilation. Thoracic fluid content significantly decreased immediately after the NPV.

Modes of Transmission of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) and Factors Influencing on the Airborne Transmission: A Review.

The multiple modes of SARS-CoV-2 transmission including airborne, droplet, contact, and fecal–oral transmissions that cause coronavirus disease 2019 (COVID-19) contribute to a public threat to the lives of people worldwide. Herein, different databases are reviewed to evaluate modes of transmission of SARS-CoV-2 and study the effects of negative pressure ventilation, air conditioning system, and related protection approaches of this virus. Droplet transmission was commonly reported to occur in particles with diameter >5 µm that can quickly settle gravitationally on surfaces (1–2 m). Instead, fine and ultrafine particles (airborne transmission) can stay suspended for an extended period of time (≥2 h) and be transported further, e.g., up to 8 m through simple diffusion and convection mechanisms. Droplet and airborne transmission of SARS-CoV-2 can be limited indoors with adequate ventilation of rooms, by routine disinfection of toilets, using negative pressure rooms, using face masks, and maintaining social distancing. Other preventive measures recommended include increasing the number of screening tests of suspected carriers of SARS-CoV-2, reducing the number of persons in a room to minimize sharing indoor air, and monitoring people’s temperature before accessing a building. The work reviews a body of literature supporting the transmission of SARS-CoV-2 through air, causing COVID-19 disease, which requires coordinated worldwide strategies.

Hemodynamic Effects of Negative Pressure Ventilation in Chronic Obstructive Pulmonary Disease

Hemodynamic Effects of Negative Pressure Ventilation in Chronic Obstructive Pulmonary Disease

Theoretical research and practice on coal mine methane extraction and ground development design

This paper, starting with the existence of general introduction of associated coal bed methane (CBM) with coal, expatiates in five parts on the transfer rules of CBM changing with time in three-dimensional rock space of the coal mine under the effect of mining activity and ventilation; On the basis above, the principle having been validated in practice is also pointed out for us to follow in methane extraction from coal mines. Finally, it draw conclusion that mining areas with high gas concentration(including coal and gas outburst), low permeability, and composite coal seams can realize the coal mine methane (CMM) extraction and ground development in a high efficient way as long as we follow the miming activities and the gas migration rules under the effect of negative pressure ventilation.

Home mechanical ventilatory support in patients with restrictive ventilatory disorders: A 48-year experience

We performed a retrospective analysis to the effects of negative pressure ventilation (NPV), tracheal intermittent positive pressure ventilation (TIPPV), and nasal intermittent positive pressure ventilation (NIPPV, volume or pressure-controlled ventilatory mode), in 114 patients with restrictive ventilatory disorders instituted in our hospital from 1956 until 2005. The patients were assigned on "ad hoc" basis to NPV, TIPPV, or NIPPV. All patients were subdivided in an idiopathic kyphoscoliosis group (IK, n=64), a post-poliomyelitis syndrome group (PP, n=30), or a miscellaneous group (M, n=20). The patients in the PP group had higher survival rates compared to the IK patients (P<0.05), while the M patients had the lowest survival rates (P<0.01). Both NPV (P<0.01) and TIPPV (P<0.05) lead to a decrease in PaCO2 after 9 months compared to baseline. This decrease in PaCO2 was still present after 5 years NPV (P<0.001) and TIPPV (P<0.05). NIPPV lead to an improvement in pulmonary function (P<0.05) and arterial blood gases (P<0.001) after 9 months compared to baseline. After 5 years NIPPV, the arterial blood gases were still significantly improved compared to baseline (P<0.01). Both volume-controlled and pressure-controlled ventilation improved pulmonary function and arterial blood gases. Long-term home mechanical ventilatory support by both NPV and positive pressure ventilation is effective in patients with IK, PP syndrome, and a M group, even after a period of 5 years.

Long-term negative pressure ventilation.

Noninvasive mechanical ventilatory techniques include the use of negative and positive pressure ventilators. Negative pressure ventilators support ventilation by exposing the surface of the chest wall to subatmospheric pressure during inspiration, whereas expiration occurs when the pressure around the chest wall increases and becomes equal to or greater than atmospheric pressure. In this article, a description of negative pressure ventilators and the physiologic effects of negative pressure ventilation (NPV) is given, and the application of this technique in the long-term treatment of chronic respiratory failure is summarized. Many studies, although uncontrolled, have shown that long-term treatment with NPV can improve respiratory muscle function, arterial blood gases, and survival in patients with neuromuscular and chest wall disorders. NPV devices, however, are more cumbersome and difficult to use than home positive pressure ventilators (PPVs) and tend to predispose to obstructive apnoeas during sleep. In the last several decades, NPV has been supplanted by mask PPV. In experienced hands, NPV remains a second viable option in patients with neuromuscular and chest wall disorders who, for technical or other reasons, cannot be offered mask PPV. There is no evidence, however, that long-term treatment with NPV can improve respiratory muscle function, exercise endurance, quality of life, and survival in patients with severe chronic obstructive pulmonary disease.

Effect of assist negative pressure ventilation by microprocessor based iron lung on breathing effort

Background: The lack of patient triggering capability during negative pressure ventilation (NPV) may contribute to poor patient synchrony and induction of upper airway collapse. This study was undertaken to evaluate...

Cardiorespiratory responses to negative pressure ventilation after tetralogy of Fallot repair: a hemodynamic tool for patients with a low-output state

ObjectivesWe hypothesized that a period of cuirass negative pressure ventilation (NPV) would augment the cardiac output of patients in the early postoperative period after complete correction of tetralogy of Fallot (TOF).BackgroundDiastolic right ventricular dysfunction can lead to a low-output state in an important minority of patients after TOF repair. In these patients, the diastolic pulmonary arterial flow, which characterizes restrictive right ventricular physiology, and on which the cardiac output is so dependent, is highly sensitive to changes in intrathoracic pressure.MethodsThe effects of NPV on pulmonary blood flow were investigated in 23 intubated children who were initially ventilated using intermittent positive pressure ventilation after TOF repair. Eight patients had restrictive right ventricular physiology. All children received a 15-min period of NPV, and eight received a prolonged period (45 min) of NPV.ResultsA brief period of NPV increased pulmonary blood flow by 39%, and the improvement further continued if the study period was extended, with a total increase of 67% after 45 min. Patients with restrictive physiology had a somewhat delayed response to NPV, but the ultimate increase during an extended period of NPV was greater in restrictive patients (84%) than nonrestrictive patients (50%).ConclusionsBy manipulating important cardiopulmonary interactions, NPV improves the cardiac output of patients after TOF repair, and has a role as a hemodynamic tool in the management of the low-output state in selected cases.

Negative pressure ventilation in the treatment of acute respiratory failure: an old noninvasive technique reconsidered.

Noninvasive mechanical ventilatory techniques include the use of negative and positive pressure ventilators. Negative pressure ventilators, such as the "iron lung", support ventilation by exposing the surface of the chest wall to subatmospheric pressure during inspiration; whereas, expiration occurs when the pressure around the chest wall increases and becomes atmospheric or greater than atmospheric. In this review, after a description of the more advanced models of tank ventilators and the physiological effects of negative pressure ventilation (NPV), we summarize the recent application of this old technique in the treatment of acute respiratory failure (ARF). Several uncontrolled studies suggest that NPV may have a potential therapeutic role in the treatment of acute on chronic respiratory failure in patients with chronic obstructive pulmonary disease and restrictive thoracic disorders, reducing the need for endotracheal intubation. In the paediatric field, after substantial technical improvement, NPV has been successfully reintroduced for the treatment of ARF due to neonatal distress syndrome and bronchopulmonary dysplasia, and for the weaning from positive pressure ventilation in intubated patients. The positive results of these reports need to be formally confirmed by further prospective and controlled studies before recommending the generalized use of negative pressure ventilation in acute respiratory failure as a standard of care.

Effect of Negative Pressure Ventilation in Severe Chronic Obstructive Pulmonary Disease

SHAPIRO STANLEY H.; ERNST, PIERRE; GRAY-DONALD, KATHERINE; MARTIN, JAMES G.; WOOD-DAUPHINEE, SHARON; SPITZER, WALTER O.; MACKLEM, PETER T.

Effect of Negative Pressure Ventilation in Severe Chronic Obstructive Pulmonary Disease

Effect of Negative Pressure Ventilation in Severe Chronic Obstructive Pulmonary Disease

Effect of negative pressure ventilation in severe chronic obstructive pulmonary disease

The hypothesis that patients with chronic obstructive pulmonary disease (COPD) have chronic inspiratory muscle fatigue was tested in an effectiveness trial in which negative pressure ventilation (NPV) was used to produce inspiratory muscle rest. In a double-blind study 184 patients with severe COPD were randomly allocated active or sham NPV treatment for a 12-week period of home use. The distance walked in a 6 min walk test was the primary outcome variable. Secondary outcome measures were cycle exercise endurance time, severity of dyspnoea, quality of life, arterial blood gas tensions, and respiratory muscle strength. The percentage reduction in amplitude of the diaphragmatic electromyographic signal multiplied by hours of N PV was used to reflect the dose of NPV so we could examine dose-response relations. Analysis was based on intention to treat. We found no evidence of a clinically or statistically significant difference in any outcome measure between active and sham groups. No dose-response relation was observed. Moreover, the intervention was poorly accepted despite substantial clinical support. We conclude that NPV as used in this study is difficult to apply and ineffective when used with the aim of resting the respiratory muscles in patients with stable COPD.

Effect of negative pressure ventilation on arterial blood gas pressures and inspiratory muscle strength during an exacerbation of chronic obstructive lung disease.

The effects of intermittent negative pressure ventilation have been studied in 20 patients with chronic obstructive pulmonary disease during an exacerbation of their disease. Measurements of arterial blood gas tensions and maximal inspiratory pressure (MIP) were performed before and after six hours of negative pressure ventilation or standard treatment (control day) given in random order on two consecutive days. After negative pressure ventilation the mean (SD) value of MIP increased from 68.1 (21.5) to 74.8 (20) cm H2O;* arterial oxygen tension (PaCO2) fell from 60.6 (12.2) to 50.9 (8.9) mm Hg* but PaO2 changed little (from 48.4 (7.4) to 47.6 (8.2) mm Hg). There were no significant changes on the control day in arterial blood gas tensions (PaO2 47.8 (8.1) and 48.9 (9.4) and Paco2 59.8 (10.9) and 57.5 (8.06) mm Hg) or in MIP (69.4 (22.4) and 70.9 (22.9) cm H2O). Six patients tolerated negative pressure ventilation poorly and these patients showed less improvement after negative pressure ventilation. Our results suggest that intermittent negative pressure ventilation can increase alveolar ventilation in patients with an exacerbation of chronic obstructive lung disease, particularly in those who tolerate the procedure well. Most subjects showed a fall in PaCO2 and an increase in MIP. The fact that PaO2 was unchanged despite the fall in PaCO2 suggests that gas exchange may deteriorate with negative pressure ventilation in these patients.

Hemodynamic Effects of Negative-Pressure Ventilation in Patients with COPD

In order to evaluate the hemodynamic effects of INPV, eight patients with COPD (FEV1/FVC, 54 +/- 6 percent; mean +/- SD), respiratory failure (PaO2, 52 +/- 6 mm Hg; PaCO2, 56 +/- 4 mm Hg), and clinical signs of inspiratory muscle fatigue underwent right cardiac catheterization while performing 20 minutes of INPV by a cuirass ventilator at a pressure (-20 to -40 cm H2O) able to reduce the diaphragmatic electromyographic activity. Patients showed a mild basal pulmonary artery hypertension. During INPV, no changes in the mean values of HR (from 79 +/- 20 to 80 +/- 18 beats per minute), systolic BP (141 +/- 19 to 139 +/- 16 mm Hg), CO (5.2 +/- 0.8 to 5.1 +/- 1.3 L/min), mean PAP (23.8 +/- 3.8 to 23.9 +/- 4.4 mm Hg), RAP (4.3 +/- 2.6 to 5.5 +/- 2.5 mm Hg), PWP (10.3 +/- 4.5 to 9.4 +/- 2.9 mm Hg), TPR (369 +/- 76 to 392 +/- 124 dynes.s.cm-5), and PVR (199 +/- 51 to 233 +/- 94 dynes.s.cm-5) were observed. Direct systemic BP monitoring could be performed in six patients. During INPV, three patients showed "pulsus paradoxus," as assessed by an inspiratory fall in systolic BP of 11, 13, and 20 mm Hg, respectively. We conclude that INPV by cuirass ventilator does not induce adverse hemodynamic effects in patients with COPD who have pulmonary artery hypertension.

Effect of negative-pressure ventilation on lung water in permeability pulmonary edema

We have previously shown (Am. Rev. Respir. Dis. 136: 886-891, 1987) improved cardiac output in dogs with pulmonary edema ventilated with external continuous negative chest pressure ventilation (CNPV) using negative end-expiratory pressure (NEEP), compared with continuous positive-pressure ventilation (CPPV) using equivalent positive end-expiratory pressure (PEEP). The present study examined the effect on lung water of CNPV compared with CPPV to determine whether the increased venous return created by NEEP worsened pulmonary edema in dogs with acute lung injury. Oleic acid (0.06 ml/kg) was administered to 27 anesthetized dogs. Supine animals were then divided into three groups and ventilated for 6 h. The first group (n = 10) was treated with intermittent positive-pressure ventilation (IPPV) alone; the second (n = 9) received CNPV with 10 cmH2O NEEP; the third (n = 8) received CPPV with 10 cmH2O PEEP. CNPV and CPPV produced similar improvements in oxygenation over IPPV. However, cardiac output was significantly depressed by CPPV, but not by CNPV, when compared with IPPV. Although there were no differences in extravascular lung water (Qwl/dQl) between CNPV and CPPV, both significantly increased Qwl/dQl compared with IPPV (7.81 +/- 0.21 and 7.87 +/- 0.31 vs. 6.71 +/- 0.25, respectively, P less than 0.01 in both instances). CNPV and CPPV, but not IPPV, enhanced lung water accumulation in the perihilar areas where interstitial pressures may be most negative at higher lung volumes.