Randomised crossover study of pressure and volume non-invasive ventilation in chest wall deformity.
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ABSTRACT: Background
Non-invasive ventilation is an established treatment for chronic respiratory failure due to chest wall deformity. There are few data available to inform the choice between volume and pressure ventilators. The aim of this study was to compare pressure and volume targeted ventilation in terms of diurnal arterial blood gas tensions, lung volumes, hypercapnic ventilatory responses, sleep quality, and effect on daytime function and health status when ventilators were carefully set to provide the same minute ventilation.Methods
Thirteen patients with chest wall deformity underwent a 4 week single blind randomised crossover study using the Breas PV403 ventilator in either pressure or volume mode with assessments made at the end of each 4 week period.Results
Minute ventilation at night was less than that set during the day with greater leakage for both modes of ventilation. There was more leakage with pressure than volume ventilation (13.8 (1.9) v 5.9 (1.0) l/min, p = 0.01). There were no significant differences in sleep quality, daytime arterial blood gas tensions, lung mechanics, ventilatory drive, health status or daytime functioning.Conclusions
These data suggest that pressure and volume ventilation are equivalent in terms of the effect on nocturnal and daytime physiology, and resulting daytime function and health status.
SUBMITTER: Tuggey JM
PROVIDER: S-EPMC1747212 | biostudies-literature | 2005 Oct
REPOSITORIES: biostudies-literature
Publications
Randomised crossover study of pressure and volume non-invasive ventilation in chest wall deformity.
Thorax 20050805 10
<h4>Background</h4>Non-invasive ventilation is an established treatment for chronic respiratory failure due to chest wall deformity. There are few data available to inform the choice between volume and pressure ventilators. The aim of this study was to compare pressure and volume targeted ventilation in terms of diurnal arterial blood gas tensions, lung volumes, hypercapnic ventilatory responses, sleep quality, and effect on daytime function and health status when ventilators were carefully set ...[more]
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| S-EPMC6457810 | biostudies-literature
Project description:Lung volume reduction (LVR) techniques improve lung function in selected patients with emphysema, but the impact of LVR procedures on the asynchronous movement of different chest wall compartments, which is a feature of emphysema, is not known.We used optoelectronic plethysmography to assess the effect of surgical and bronchoscopic LVR on chest wall asynchrony. Twenty-six patients were assessed before and 3 months after LVR (surgical [n = 9] or bronchoscopic [n = 7]) or a sham/unsuccessful bronchoscopic treatment (control subjects, n = 10). Chest wall volumes were divided into six compartments (left and right of each of pulmonary ribcage [Vrc,p], abdominal ribcage [Vrc,a], and abdomen [Vab]) and phase shift angles (?) calculated for the asynchrony between Vrc,p and Vrc,a (?RC), and between Vrc,a and Vab (?DIA).Participants had an FEV? of 34.6 ± 18% predicted and a residual volume of 217.8 ± 46.0% predicted with significant chest wall asynchrony during quiet breathing at baseline (?RC, 31.3° ± 38.4°; and ?DIA, -38.7° ± 36.3°). Between-group difference in the change in ?RC and ?DIA during quiet breathing following treatment was 44.3° (95% CI, -78 to -10.6; P = .003) and 34.5° (95% CI, 1.4 to 67.5; P = .007) toward 0° (representing perfect synchrony), respectively, favoring the LVR group. Changes in ?RC and ?DIA were statistically significant on the treated but not the untreated sides.Successful LVR significantly reduces chest wall asynchrony in patients with emphysema.
| S-EPMC4493874 | biostudies-other
Project description:BackgroundNon-invasive positive pressure ventilation (NPPV) has been used to treat respiratory distress due to acute cardiogenic pulmonary oedema (ACPE). We performed a systematic review and meta-analysis update on NPPV for adults presenting with ACPE.ObjectivesTo evaluate the safety and effectiveness of NPPV compared to standard medical care (SMC) for adults with ACPE. The primary outcome was hospital mortality. Important secondary outcomes were endotracheal intubation, treatment intolerance, hospital and intensive care unit length of stay, rates of acute myocardial infarction, and adverse event rates.Search methodsWe searched CENTRAL (CRS Web, 20 September 2018), MEDLINE (Ovid, 1946 to 19 September 2018), Embase (Ovid, 1974 to 19 September 2018), CINAHL Plus (EBSCO, 1937 to 19 September 2018), LILACS, WHO ICTRP, and clinicaltrials.gov. We also reviewed reference lists of included studies. We applied no language restrictions.Selection criteriaWe included blinded or unblinded randomised controlled trials in adults with ACPE. Participants had to be randomised to NPPV (continuous positive airway pressure (CPAP) or bilevel NPPV) plus standard medical care (SMC) compared with SMC alone.Data collection and analysisTwo review authors independently screened and selected articles for inclusion. We extracted data with a standardised data collection form. We evaluated the risks of bias of each study using the Cochrane 'Risk of bias' tool. We assessed evidence quality for each outcome using the GRADE recommendations.Main resultsWe included 24 studies (2664 participants) of adult participants (older than 18 years of age) with respiratory distress due to ACPE, not requiring immediate mechanical ventilation. People with ACPE presented either to an Emergency Department or were inpatients. ACPE treatment was provided in an intensive care or Emergency Department setting. There was a median follow-up of 13 days for hospital mortality, one day for endotracheal intubation, and three days for acute myocardial infarction. Compared with SMC, NPPV may reduce hospital mortality (risk ratio (RR) 0.65, 95% confidence interval (CI) 0.51 to 0.82; participants = 2484; studies = 21; I2 = 6%; low quality of evidence) with a number needed to treat for an additional beneficial outcome (NNTB) of 17 (NNTB 12 to 32). NPPV probably reduces endotracheal intubation rates (RR 0.49, 95% CI 0.38 to 0.62; participants = 2449; studies = 20; I2 = 0%; moderate quality of evidence) with a NNTB of 13 (NNTB 11 to 18). There is probably little or no difference in acute myocardial infarction (AMI) incidence with NPPV compared to SMC for ACPE (RR 1.03, 95% CI 0.91 to 1.16; participants = 1313; studies = 5; I2 = 0%; moderate quality of evidence). We are uncertain as to whether NPPV increases hospital length of stay (mean difference (MD) -0.31 days, 95% CI -1.23 to 0.61; participants = 1714; studies = 11; I2 = 55%; very low quality of evidence). Adverse events were generally similar between NPPV and SMC groups, but evidence was of low quality.Authors' conclusionsOur review provides support for continued clinical application of NPPV for ACPE, to improve outcomes such as hospital mortality and intubation rates. NPPV is a safe intervention with similar adverse event rates to SMC alone. Additional research is needed to determine if specific subgroups of people with ACPE have greater benefit of NPPV compared to SMC. Future research should explore the benefit of NPPV for ACPE patients with hypercapnia.
| S-EPMC6449889 | biostudies-literature
Project description:ObjectivesLow tidal volume (= tidal volume ≤ 6 mL/kg, predicted body weight) ventilation using volume control benefits patients with acute respiratory distress syndrome. Airway pressure release ventilation is an alternative to low tidal volume-volume control ventilation, but the release breaths generated are variable and can exceed tidal volume breaths of low tidal volume-volume control. We evaluate the application of a low tidal volume-compatible airway pressure release ventilation protocol that manages release volumes on both clinical and feasibility endpoints.DesignWe designed a prospective randomized trial in patients with acute hypoxemic respiratory failure. We randomized patients to low tidal volume-volume control, low tidal volume-airway pressure release ventilation, and traditional airway pressure release ventilation with a planned enrollment of 246 patients. The study was stopped early because of low enrollment and inability to consistently achieve tidal volumes less than 6.5 mL/kg in the low tidal volume-airway pressure release ventilation arm. Although the primary clinical study endpoint was PaO2/FIO2 on study day 3, we highlight the feasibility outcomes related to tidal volumes in both arms.SettingFour Intermountain Healthcare tertiary ICUs.PatientsAdult ICU patients with hypoxemic respiratory failure anticipated to require prolonged mechanical ventilation.InterventionsLow tidal volume-volume control, airway pressure release ventilation, and low tidal volume-airway pressure release ventilation.Measurements and main resultsWe observed wide variability and higher tidal (release for airway pressure release ventilation) volumes in both airway pressure release ventilation (8.6 mL/kg; 95% CI, 7.8-9.6) and low tidal volume-airway pressure release ventilation (8.0; 95% CI, 7.3-8.9) than volume control (6.8; 95% CI, 6.2-7.5; p = 0.005) with no difference between airway pressure release ventilation and low tidal volume-airway pressure release ventilation (p = 0.58). Recognizing the limitations of small sample size, we observed no difference in 52 patients in day 3 PaO2/ FIO2 (p = 0.92). We also observed no significant difference between arms in sedation, vasoactive medications, or occurrence of pneumothorax.ConclusionsAirway pressure release ventilation resulted in release volumes often exceeding 12 mL/kg despite a protocol designed to target low tidal volume ventilation. Current airway pressure release ventilation protocols are unable to achieve consistent and reproducible delivery of low tidal volume ventilation goals. A large-scale efficacy trial of low tidal volume-airway pressure release ventilation is not feasible at this time in the absence of an explicit, generalizable, and reproducible low tidal volume-airway pressure release ventilation protocol.
| S-EPMC6250244 | biostudies-literature
Project description:BackgroundDamage caused by lung overdistension (volutrauma) has been implicated in the development of bronchopulmonary dysplasia (BPD). Modern neonatal ventilation modes can target a set tidal volume as an alternative to traditional pressure-limited ventilation (PLV) using a fixed inflation pressure. Volume-targeted ventilation (VTV) aims to produce a more stable tidal volume in order to reduce lung damage and stabilise the partial pressure of carbon dioxide (pCO2).ObjectivesTo determine whether VTV compared with PLV leads to reduced rates of death and death or BPD in newborn infants and to determine whether use of VTV affected outcomes including air leak, cranial ultrasound findings and neurodevelopment.Search methodsWe used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 12), MEDLINE via PubMed (1966 to 13 January 2017), Embase (1980 to 13 January 2017) and CINAHL (1982 to 13 January 2017). We also searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. We contacted the principal investigators of studies to obtain supplementary information.Selection criteriaRandomised and quasi-randomised trials comparing VTV versus PLV in infants of less than 44 weeks' postmenstrual age and reporting clinically relevant outcomes.Data collection and analysisWe assessed risk of bias for each trial using Cochrane methodology. We evaluated quality of evidence for each outcome using GRADE criteria. We tabulated mortality, rates of BPD, short-term clinical outcomes and long-term developmental outcomes.Statisticsfor categorical outcomes, we calculated typical estimates for risk ratios (RR), risk differences (RD) and number needed to treat for an additional beneficial outcome (NNTB). For continuous variables, we calculated typical estimates for mean differences (MD). We used 95% confidence intervals (CI) and assumed a fixed-effect model for meta-analysis.Main resultsTwenty randomised trials met our inclusion criteria; 16 parallel trials (977 infants) and four cross-over trials (88 infants). No studies were blinded and the quality of evidence for outcomes assessed varied from moderate to low.We found no difference in the primary outcome, death before hospital discharge, between VTV modes versus PLV modes (typical RR 0.75, 95% CI 0.53 to 1.07; low quality evidence). However, there was moderate quality evidence that the use of VTV modes resulted in a reduction in the primary outcome, death or BPD at 36 weeks' gestation (typical RR 0.73, 95% CI 0.59 to 0.89; typical NNTB 8, 95% CI 5 to 20) and the following secondary outcomes: rates of pneumothorax (typical RR 0.52, 95% CI 0.31 to 0.87; typical NNTB 20, 95% CI 11 to 100), mean days of mechanical ventilation (MD -1.35 days, 95% CI -1.83 to -0.86), rates of hypocarbia (typical RR 0.49, 95% CI 0.33 to 0.72; typical NNTB 3, 95% CI 2 to 5), rates of grade 3 or 4 intraventricular haemorrhage (typical RR 0.53, 95% CI 0.37 to 0.77; typical NNTB 11, 95% CI 7 to 25) and the combined outcome of periventricular leukomalacia with or without grade 3 or 4 intraventricular haemorrhage (typical RR 0.47, 95% CI 0.27 to 0.80; typical NNTB 11, 95% CI 7 to 33). VTV modes were not associated with any increased adverse outcomes.Authors' conclusionsInfants ventilated using VTV modes had reduced rates of death or BPD, pneumothoraces, hypocarbia, severe cranial ultrasound pathologies and duration of ventilation compared with infants ventilated using PLV modes. Further studies are needed to identify whether VTV modes improve neurodevelopmental outcomes and to compare and refine VTV strategies.
| S-EPMC6485452 | biostudies-literature
Project description:Record keeping for patients on non-invasive ventilation (NIV) at St. Georges Hospital is poor. The initial NIV prescription is often not recorded, and changes to the NIV prescription or the rationale for the changes (ABG results) are also poorly documented. This leads to confusion for nurses/doctors as to what the correct settings are, meaning patients could receive ineffective ventilation. The use of NIV is also poorly recorded by nursing staff meaning that doctors are unsure if the prescribed NIV is being achieved. This can lead to treatment being escalated unnecessarily in the event of treatment failure. Non-invasive ventilation (NIV) is the provision of ventilatory support in the form of positive pressure via the patient's upper airway using a mask or similar device. NIV is indicated for treatment of acute hypercapnic respiratory failure, of which there are many causes, though COPD is the indication in up to 70% of cases.[1] British Thoracic Society (BTS) guidelines for NIV suggest that the rationale for commencing a patient on NIV and the proposed settings should be clearly documented.[2] Clinicians cannot effectively tailor changes to the patients NIV settings if this information is not clearly recorded, which could lead to increased time requiring NIV or NIV failure. Three main areas were considered important to measure for this project. The initial prescription of the NIV, changes to the NIV settings, and nursing documentation surrounding NIV. A baseline measurement of NIV documentation for two weeks found NIV documentation to globally very poor. NIV was formally prescribed 29% of the time, full detail of intended settings were documented 57% of the time, the decision to commence NIV was discussed with the respiratory consultant/SpR just 29% of the time and on no occasion was a decision regarding escalation of treatment recorded. Eighteen changes were made to the NIV settings. These were formally prescribed 22% of the time and detail of the intended settings was recorded 44% of the time. Nursing documentation included detail on the length of NIV use just 21% of the time, and comments on the NIV use were left just 33% of the time. The intervention was a unified four page NIV prescription chart. Page 1: An area for the NIV to be initially prescribed with reminder questions for important considerations. Page 2: An area for changes to be made to the NIV settings. Page 3: An area for the most up to date NIV/respiratory plan to be documented. Page 4: Nursing documentation, with prompts for the time NIV was put on/off and for comments. The chart was printed at St Georges print services and paid for by the respiratory ward. A further two weeks of monitoring followed after implementation of the new chart. Improvements were seen in all areas of documentation surrounding NIV. The NIV was formally prescribed 86% of the time compared to 29% pre-intervention. The NIV settings were stated 100% of the time in the initial prescription. An escalation decision was recorded 71% of the time. Changes to the NIV settings improved to 92%. Nursing documentation improved greatly. The length of the NIV use was recorded for 91% of NIV days compared to 21% previously (p<0.001), and comments on the use of NIV improved from from 33% to 98% (p<0.001). Cases where the documentation remained poor were in those patients for whom the new chart had not been used. The implementation of a unified NIV prescription chart to be kept in the bedside notes on the respiratory ward greatly improved documentation surrounding NIV. Further work must be done to ensure that the chart is used 100% of the time. This will include adjusting the chart to reduce the workload to use it, rolling the chart out on the acute medical ward, and submitting the chart to the trust board for its acceptance as an official trust chart.
| S-EPMC4645943 | biostudies-literature
Project description:Goal: COSMIC Medical, a Vancouver-based open-source volunteer initiative, has designed an accessible, affordable, and aerosol-confining non-invasive positive-pressure ventilator (NIPPV) device, known as the COSMIC Bubble Helmet (CBH). This device is intended for COVID-19 patients with mild-to-moderate acute respiratory distress syndrome. System Design: CBH is composed of thermoplastic polyurethane, which creates a flexible neck seal and transparent hood. This device can be connected to wall oxygen, NIPPVs including Continuous Positive Airway Pressure and Bi-level Positive Airway Pressure, and mechanical ventilators. Discussion: Justification of CBH design components relied on several factors, predominantly the safety and comfort of patients and healthcare providers. Conclusion: CBH has implications within and outside of the pandemic, as an alternative to invasive mechanical ventilation methods. We have experimentally verified that CBH is effective in minimizing aerosolization risks and performs at specified clinical requirements.
| S-EPMC8545034 | biostudies-literature
Project description:INTRODUCTION:Managing ventilation and oxygenation during laparoscopic procedures in severely obese patients undergoing weight loss surgery presents many challenges. Pressure-controlled ventilation, volume-guaranteed (PCV-VG) is a dual-control mode of ventilation and an alternative to pressure (PC) or volume (VC) controlled ventilation. PCV-VG features a user-selected tidal volume target, that is auto-regulated and pressure controlled. We hypothesized that PCV-VG ventilation would provide improved oxygenation and ventilation during laparoscopic bariatric surgery with a lower peak inflating pressure (PIP) than either PC or VC ventilation. METHODS:This was a prospective cross-over cohort trial (n = 20). In random sequence each patient received the three modes of ventilation for 20 minutes during the laparoscopic portion of the procedure. For all modes of ventilation the goal tidal volume was 6-8 mL/kg, and the respiratory rate was adjusted to achieve normocarbia. The PIP, exhaled tidal volume, respiratory rate, and oxygen saturation were recorded every five minutes. At the end of 20 minutes, an arterial blood gas was obtained. Data were analyzed using a paired t-test. RESULTS:PCV-VG and PC ventilation both resulted in significantly lower PIP (cmH2O) than VC ventilation (30.5 ± 3.0, 31.6 ± 4.9, and 36.3 ± 3.4 mmHg respectively; p < 0.01 for PCV-VG vs. VC and PC vs. VC). There was no difference in oxygenation (PaO2), ventilation (PaCO2) or hemodynamic variables between the three ventilation modes. CONCLUSIONS:In adolescents and young adults undergoing laparoscopic bariatric surgery, PCV-VG and PC were superior to VC ventilation in their ability to provide ventilation with the lowest PIP.
| S-EPMC4161575 | biostudies-literature
Project description:BackgroundAltitude and gravity changes during aeromedical evacuations induce exacerbated cardiovascular responses in unstable patients. Non-invasive cardiac output monitoring is difficult to perform in this environment with limited access to the patient. We evaluated the feasibility and accuracy of stroke volume estimation by finger photoplethysmography (SVp) in hypergravity.MethodsFinger arterial blood pressure (ABP) waveforms were recorded continuously in ten healthy subjects before, during and after exposure to +Gz accelerations in a human centrifuge. The protocol consisted of a 2-min and 8-min exposure up to +4 Gz. SVp was computed from ABP using Liljestrand, systolic area, and Windkessel algorithms, and compared with reference values measured by echocardiography (SVe) before and after the centrifuge runs.ResultsThe ABP signal could be used in 83.3% of cases. After calibration with echocardiography, SVp changes did not differ from SVe and values were linearly correlated (p<0.001). The three algorithms gave comparable SVp. Reproducibility between SVp and SVe was the best with the systolic area algorithm (limits of agreement -20.5 and +38.3 ml).ConclusionsNon-invasive ABP photoplethysmographic monitoring is an interesting technique to estimate relative stroke volume changes in moderate and sustained hypergravity. This method may aid physicians for aeronautic patient monitoring.
| S-EPMC4370450 | biostudies-literature
Project description:BackgroundGuidelines recommend mechanical ventilation with Intermitted Positive Pressure Ventilation (IPPV) during resuscitation. The influence of the novel ventilator mode Chest Compression Synchronized Ventilation (CCSV) on gas exchange and arterial blood pressure compared with IPPV was investigated in a pig model.MethodsIn 12 pigs (general anaesthesia/intubation) ventricular fibrillation was induced and continuous chest compressions were started after 3 min. Pigs were mechanically ventilated in a cross-over setting with 5 ventilation periods of 4 min each: Ventilation modes were during the first and last period IPPV (100% O2, tidal volumes = 7 ml/kgKG, respiratory rate = 10/min), during the 2nd, 3rd and 4th period CCSV (100% O2), a pressure-controlled and with each chest compression synchronized breathing pattern with three different presets in randomized order. Presets: CCSVA: P insp = 60 mbar, inspiratory time = 205 ms; CCSVB: P insp = 60 mbar, inspiratory time = 265 ms; CCSVC: P insp = 45 mbar, inspiratory time = 265 ms. Blood gas samples were drawn for each period, mean arterial (MAP) and central venous (CVP) blood pressures were continuously recorded. Results as median (25%/75%percentiles).ResultsVentilation with each CCSV mode resulted in higher PaO2 than IPPV: PaO2: IPPV first: 19.6(13.9/36.2)kPa, IPPV last: 22.7(5.4/36.9)kPa (p = 0.77 vs IPPV first), CCSVA: 48.9(29.0/58.2)kPa (p = 0.028 vs IPPV first, p = 0.0001 vs IPPV last), CCSVB: 54.0 (43.8/64.1) (p = 0.001 vs IPPV first, p = 0.0001 vs IPPV last), CCSVC: 46.0 (20.2/58.4) (p = 0.006 vs IPPV first, p = 0.0001 vs IPPV last). Both the MAP and the difference MAP-CVP did not decrease during twelve minutes CPR with all three presets of CCSV and were higher than the pressures of the last IPPV period.ConclusionsAll patterns of CCSV lead to a higher PaO2 and avoid an arterial blood pressure drop during resuscitation compared to IPPV in this pig model of cardiac arrest.
| S-EPMC4444197 | biostudies-literature