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Davidson AC, Banham S, Elliott M, Kennedy D, Gelder C, Glossop A, Church AC, Creagh-Brown B, Dodd JW, Felton T, Foëx B, Mansfield L, McDonnell L, Parker R, Patterson CM, Sovani M, Thomas L. BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults. Thorax 2016; 71 Suppl 2:ii1-35. [DOI: 10.1136/thoraxjnl-2015-208209] [Citation(s) in RCA: 195] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Abstract
Chronic obstructive pulmonary disease (COPD) is considered to be one of the most frequent pulmonary diseases in industrialized countries. Non-invasive ventilation (NIV) is the first choice therapy in acute exacerbations of chronic hypercapnic respiratory failure (AE-COPD). Effective delivery of NIV requires a specialized interdisciplinary team with sufficient monitoring. NIV is delivered as assisted positive pressure ventilation where high inspiratory flow and peak pressure are required. The external positive end expiratory pressure (PEEP) should be adjusted to the intrinsic PEEP. Criteria of success are improvement in the clinical, especially neurological condition as well as improvement of pH and PaCO(2). Patients with a pH between 7.25 and 7.35 have demonstrated most benefit from NIV. In cases of patients not responding to NIV endotracheal intubation should be initiated in a timely manner. Assisted ventilation modes are preferred over controlled ventilation modes in intubated COPD patients. Settings of respirators have to be aimed at a reduction of intrinsic PEEP and dynamic hyperinflation. This includes sufficient external PEEP, long expiration times and low respiratory frequencies even allowing for permissive hypercapnia.
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Abstract
BACKGROUND Asthma remains a common chronic illness in pregnancy with the potential for catastrophic complications. Most women with asthma exacerbation can be treated with medical management and continuation of pregnancy. However, refractory cases may necessitate delivery for fetal or maternal indications. CASE We report a case of status asthmaticus at 33 weeks of gestation with significant maternal respiratory acidosis and difficulty with ventilation necessitating delivery by cesarean delivery in the medical intensive care unit. The patient was unresponsive to standard medical therapies. Delivery resulted in immediate improvement in maternal ventilation parameters. CONCLUSION In cases of life-threatening status asthmaticus refractory to standard medical and ventilatory therapies in the third trimester, cesarean delivery should be considered as a final effort to increase tidal volumes and improve maternal gas exchange.
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Brulotte CA, Lang ES. Acute exacerbations of chronic obstructive pulmonary disease in the emergency department. Emerg Med Clin North Am 2012; 30:223-47, vii. [PMID: 22487106 DOI: 10.1016/j.emc.2011.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Chronic obstructive pulmonary disease (COPD) is a significant cause of morbidity and mortality worldwide. Acute exacerbations of COPD (AECOPDs) are a common presentation to emergency departments and are an important cause of respiratory failure. This article discusses the disease process and diagnosis of COPD and AECOPD. A further in-depth discussion is undertaken of evidence-based treatments, palliation, and disposition of patients who present to emergency departments with AECOPD.
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Affiliation(s)
- Cory A Brulotte
- Department of Emergency Medicine, Alberta Health Services: Calgary Zone, Foothills Medical Center, 1403 29th Street Northwest, Room C231, Calgary, Alberta, Canada T2N 2T9.
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Di Marco F, Centanni S, Bellone A, Messinesi G, Pesci A, Scala R, Perren A, Nava S. Optimization of ventilator setting by flow and pressure waveforms analysis during noninvasive ventilation for acute exacerbations of COPD: a multicentric randomized controlled trial. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2011; 15:R283. [PMID: 22115190 PMCID: PMC3388700 DOI: 10.1186/cc10567] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 10/21/2011] [Accepted: 11/24/2011] [Indexed: 12/22/2022]
Abstract
Introduction The analysis of flow and pressure waveforms generated by ventilators can be useful in the optimization of patient-ventilator interactions, notably in chronic obstructive pulmonary disease (COPD) patients. To date, however, a real clinical benefit of this approach has not been proven. Methods The aim of the present randomized, multi-centric, controlled study was to compare optimized ventilation, driven by the analysis of flow and pressure waveforms, to standard ventilation (same physician, same initial ventilator setting, same time spent at the bedside while the ventilator screen was obscured with numerical data always available). The primary aim was the rate of pH normalization at two hours, while secondary aims were changes in PaCO2, respiratory rate and the patient's tolerance to ventilation (all parameters evaluated at baseline, 30, 120, 360 minutes and 24 hours after the beginning of ventilation). Seventy patients (35 for each group) with acute exacerbation of COPD were enrolled. Results Optimized ventilation led to a more rapid normalization of pH at two hours (51 vs. 26% of patients), to a significant improvement of the patient's tolerance to ventilation at two hours, and to a higher decrease of PaCO2 at two and six hours. Optimized ventilation induced physicians to use higher levels of external positive end-expiratory pressure, more sensitive inspiratory triggers and a faster speed of pressurization. Conclusions The analysis of the waveforms generated by ventilators has a significant positive effect on physiological and patient-centered outcomes during acute exacerbation of COPD. The acquisition of specific skills in this field should be encouraged. Trial registration ClinicalTrials.gov NCT01291303.
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Affiliation(s)
- Fabiano Di Marco
- Pneumologia Ospedale San Paolo, Università degli Studi di Milano, via A, di Rudinì 8, Milano, 20142, Italy.
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García Vicente E, Sandoval Almengor JC, Díaz Caballero LA, Salgado Campo JC. [Invasive mechanical ventilation in COPD and asthma]. Med Intensiva 2011; 35:288-98. [PMID: 21216495 DOI: 10.1016/j.medin.2010.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2010] [Revised: 11/03/2010] [Accepted: 11/03/2010] [Indexed: 11/18/2022]
Abstract
COPD and asthmatic patients use a substantial proportion of mechanical ventilation in the ICU, and their overall mortality with ventilatory support can be significant. From the pathophysiological standpoint, they have increased airway resistance, pulmonary hyperinflation, and high pulmonary dead space, leading to increased work of breathing. If ventilatory demand exceeds work output of the respiratory muscles, acute respiratory failure follows. The main goal of mechanical ventilation in this kind of patients is to improve pulmonary gas exchange and to allow for sufficient rest of compromised respiratory muscles to recover from the fatigued state. The current evidence supports the use of noninvasive positive-pressure ventilation for these patients (especially in COPD), but invasive ventilation also is required frequently in patients who have more severe disease. The physician must be cautious to avoid complications related to mechanical ventilation during ventilatory support. One major cause of the morbidity and mortality arising during mechanical ventilation in these patients is excessive dynamic pulmonary hyperinflation (DH) with intrinsic positive end-expiratory pressure (intrinsic PEEP or auto-PEEP). The purpose of this article is to provide a concise update of the most relevant aspects for the optimal ventilatory management in these patients.
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Seo YK, Lee CH, Lee HK, Lee YM, Park HK, Choi SB, Kim HG, Jang HJ, Yum HK, Lee SH. Differences between Patients with TB-Destroyed Lung and Patients with COPD Admitted to the ICU. Tuberc Respir Dis (Seoul) 2011. [DOI: 10.4046/trd.2011.70.4.323] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Young Kyeong Seo
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University College of Medicine, Busan, Korea
| | - Chae Hun Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University College of Medicine, Busan, Korea
| | - Hyun-Kyung Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University College of Medicine, Busan, Korea
| | - Young Min Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University College of Medicine, Busan, Korea
| | - Hye Kyeong Park
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University College of Medicine, Busan, Korea
| | - Sang Bong Choi
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University College of Medicine, Busan, Korea
| | - Hyun Gook Kim
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University College of Medicine, Busan, Korea
| | - Hang-Jea Jang
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University College of Medicine, Busan, Korea
| | - Ho-Kee Yum
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University College of Medicine, Busan, Korea
| | - Seung Heon Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University College of Medicine, Busan, Korea
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Jung C, Lauten A, Pfeifer R, Bahrmann P, Figulla HR, Ferrari M. Pumpless Extracorporeal Lung Assist for the Treatment of Severe, Refractory Status Asthmaticus. J Asthma 2010; 48:111-3. [PMID: 21039186 DOI: 10.3109/02770903.2010.528500] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Christian Jung
- Clinic of Internal Medicine I, Friedrich-Schiller-University, Jena, Germany.
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Rose L, Gerdtz MF. Use of invasive mechanical ventilation in Australian emergency departments. Emerg Med Australas 2010; 21:108-16. [PMID: 19422407 DOI: 10.1111/j.1742-6723.2009.01167.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE There are few published reports describing the use of invasive mechanical ventilation in EDs. We explored the characteristics of patients receiving mechanical ventilation, the ventilator modes and parameters used as well as the duration of ventilation and the nature of ventilator decision-making in Australian ED. METHODS We conducted a 2 month prospective survey of adult patients who received invasive mechanical ventilation in 24 Australian ED. Data forms were completed by ED staff during the patient's ED presentation. We documented ventilator settings post intubation, after a 1 h stabilization period, and immediately before ED discharge or extubation. The person responsible for selection of ventilator settings was noted at each time point. RESULTS Data were recorded on 307 patients. Altered mental status (179/307 [58%, 95% CI 53-64]) was the most common indication for mechanical ventilation. Volume-controlled modes were most frequently used at all measured time points; with a median tidal volume of 8 mL/kg. Responsibility for initial selection of ventilator settings was shared between ED physicians (157/307 [51%, 95% CI 46-57]), ED nurses (111/307 [36%, 95% CI 31-42]) and ICU or paramedic staff (9/307 [3%, 95% CI 1-5]) (not recorded 30/307 [10%, 95% CI 6-13]). Ongoing responsibility for titration of ventilation was more commonly that of the ED nurse. CONCLUSION The application of mechanical ventilation was similar to descriptions reported in the critical care literature both in Australia and internationally. Decision-making responsibilities were shared by ED medical and nursing staff.
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Affiliation(s)
- Louise Rose
- Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Toronto, Ontario, Canada.
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Abstract
Over the past several years, there has been an introduction of numerous modes of mechanical ventilation, each with their own advantages and limitations. This article reviews the common modes of mechanical ventilation, new technologies, and specific ventilator strategies that have been shown to be beneficial. In addition, it reviews the steps that should be taken when troubleshooting a ventilator.
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Affiliation(s)
- Jairo I Santanilla
- Division of Critical Care Medicine, University of California, San Francisco, 505 Parnassus Avenue, M-917, San Francisco, CA 94143-0624, USA.
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Clinical concise review: Mechanical ventilation of patients with chronic obstructive pulmonary disease. Crit Care Med 2008; 36:1614-9. [DOI: 10.1097/ccm.0b013e318170f0f3] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Jolliet P, Tassaux D. Clinical review: patient-ventilator interaction in chronic obstructive pulmonary disease. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2007; 10:236. [PMID: 17096868 PMCID: PMC1794446 DOI: 10.1186/cc5073] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mechanically ventilated patients with chronic obstructive pulmonary disease often prove challenging to the clinician due to the complex pathophysiology of the disease and the high risk of patient-ventilator asynchrony. These problems are encountered in both intubated patients and those ventilated with noninvasive ventilation. Much knowledge has been gained over the years in our understanding of the mechanisms underlying the difficult interaction between these patients and the machines used to provide them with the ventilatory support they often require for prolonged periods. This paper attempts to summarize the various key issues of patient-ventilator interaction during pressure support ventilation, the most often used partial ventilatory support mode, and to draw clinicians' attention to the need for sufficient knowledge when setting the ventilator at the bedside, given the often conflicting goals that must be met.
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Affiliation(s)
- Philippe Jolliet
- Intensive Care, University Hospital, 1211 Geneva 14, Switzerland.
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Estrada-Y-Martin RM, Brown SD. Chronic Obstructive Pulmonary Disease. CARDIOVASCULAR MEDICINE 2007. [DOI: 10.1007/978-1-84628-715-2_109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Mattison S, Christensen M. The pathophysiology of emphysema: considerations for critical care nursing practice. Intensive Crit Care Nurs 2006; 22:329-37. [PMID: 16901700 DOI: 10.1016/j.iccn.2006.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Revised: 03/06/2006] [Accepted: 03/12/2006] [Indexed: 11/30/2022]
Abstract
Emphysema is caused by exposure to cigarette smoking as well as alpha(1)-antitrypsin deficiency. It has been estimated to cost the National Health Service (NHS) in excess of 800 million pounds per year in related health care costs. The challenges for Critical Care nurses are those associated with dynamic hyperinflation, Auto-PEEP, malnutrition and the weaning from invasive and non-invasive mechanical ventilation. In this paper we consider the impact of the pathophysiology of emphysema, its effects on other body systems as well as the impact acute exacerbations have when patients are admitted to the Intensive Care Unit.
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Affiliation(s)
- Sue Mattison
- Bournemouth University, Christchurch Road, Bournemouth, United Kingdom
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Glérant JC, Leleu O, Rose D, Mayeux I, Jounieaux V. Oxygen consumption and PEEPe in ventilated COPD patients. Respir Physiol Neurobiol 2005; 146:117-24. [PMID: 15766900 DOI: 10.1016/j.resp.2004.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2004] [Indexed: 10/26/2022]
Abstract
The intrinsic positive-end-expiratory pressure (PEEPi) increases the inspiratory load, the cost of breathing and thus oxygen consumption (V(O2)). It has been shown that applying an extrinsic positive-end-expiratory pressure (PEEPe) reduces the inspiratory threshold load but the optimal PEEPe level is still in debate. We hypothesize that the best level of PEEPe could induce a decrease in V(O2) by reducing the V(O2) demands from PEEPi. Nine mechanically ventilated COPD patients were included. The level of PEEPe was determined in accordance with the static PEEPi. V(O2) was measured using an automatic gas analyser during synchronized intermittent mandatory ventilation (SIMV): without PEEPe, with a PEEPe equal to 50% of static PEEPi and with a PEEPe equal to 100% of static PEEPi. Static PEEPi appeared to be significantly correlated with the degree of airflow obstruction (FEV1) (P<0.05). Applying a PEEPe equal to static PEEPi resulted in a significant decrease in V(O2) (P<0.05) whereas the change in V(O2) proved to be unpredictable for a PEEPe level of 50% of static PEEPi. In conclusion, V(O2) decreases progressively when increasing PEEPe up to a level equal to 100% of static PEEPi. Thus, in mechanically ventilated COPD patients with a FEV1 < or = 1000 ml, applying a PEEPe of 5 cmH2O should be recommended.
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Affiliation(s)
- J-Ch Glérant
- Respiratory Department and Intensive Care Unit, 80054 Amiens Cedex 1, France
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Gainnier M, Arnal JM, Gerbeaux P, Donati S, Papazian L, Sainty JM. Helium-oxygen reduces work of breathing in mechanically ventilated patients with chronic obstructive pulmonary disease. Intensive Care Med 2003; 29:1666-70. [PMID: 12897990 DOI: 10.1007/s00134-003-1911-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2002] [Accepted: 06/13/2003] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To evaluate whether helium-oxygen mixture reduces inspiratory work of breathing (WOB) in sedated, paralyzed, and mechanically ventilated patients with acute exacerbation of chronic obstructive pulmonary disease (COPD). DESIGN AND SETTING Open, prospective, randomized, crossover study in the medical intensive care unit in a university hospital. PATIENTS AND PARTICIPANTS 23 patients admitted for acute exacerbation of COPD and mechanically ventilated. MEASUREMENTS Total WOB (WOBt), elastic WOB (WOBel), resistive WOB (WOBres), and WOB due to PEEPi (WOBPeepi) were measured. Static intrinsic positive end expiratory pressure (PEEPi), static compliance (Crs), inspiratory resistance (Rins), inspiratory (tinsp) and expiratory time constant (texp) were also measured. These variables were compared between air-oxygen and helium-oxygen mixtures. RESULTS WOBt significantly decreased with helium-oxygen (2.34+/-1.04 to 1.85+/-1.01 J/l, p<0.001). This reduction was significant for WOBel (1.02+/-0.61 J/l to 0.87+/-0.47, p<0.01), WOBPeepi (0.77+/-0.38 J/l to 0.54+/-0.38, p<0.001), and WOBres (0.55+/-0.19 J/l to 0.44+/-0.24, p<0.05). PEEPi, Rins, tinsp and texp significantly decreased. Crs was unchanged. CONCLUSIONS Helium-oxygen mixture decreases WOB in mechanically ventilated COPD patients. Helium-oxygen mixture could be useful to reduce the burden of ventilation.
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Affiliation(s)
- Marc Gainnier
- Medical Intensive Care Unit, Hôpital Sainte-Marguerite, 13274 Marseille 9, France.
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Abstract
Ventilatory intervention is often life-saving when patients with asthma or chronic obstructive pulmonary disease (COPD) experience acute respiratory compromise. Although both noninvasive and invasive ventilation methods may be viable initial choices, which is better depends upon the severity of illness, the rapidity of response, coexisting disease, and capacity of the medical environment. In addition, noninvasive ventilation often relieves dyspnea and hypoxemia in patients with stable severe COPD. On the basis of current evidence, the general principles of ventilatory management common to patients with acutely exacerbated asthma/COPD are these: noninvasive ventilation is suitable for a relatively simple condition, but invasive ventilation is usually required in patients with more complex or more severe disease. It is crucial to provide controlled hypoventilation, longer expiratory time, and titrated extrinsic positive end-expiratory pressure to avoid dynamic hyperinflation and its attendant consequences. Controlled sedation helps achieve synchrony of triggering, power, and breath timing between patient and ventilator. When feasible, noninvasive ventilation often facilitates the weaning of ventilator-dependent patients with COPD and shortens the patient's stay in the intensive care unit.
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Affiliation(s)
- Yin Peigang
- Pulmonary Department, Regions Hospital, St. Paul, Minnesota 55101, USA
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Visser WA, Liem TH, Brouwer RM. High thoracic epidural anesthesia for coronary artery bypass graft surgery in a patient with severe obstructive lung disease. J Cardiothorac Vasc Anesth 2001; 15:758-60. [PMID: 11748529 DOI: 10.1053/jcan.2001.28334] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- W A Visser
- Department of Anesthesiology, University Hospital Nijmegen, PO Box 9101, 6500 HB Nijmegen, The Netherlands
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Añón Elizalde JM, García De Lorenzo Mateos A, Alvarez-Sala Walther R, Escuela Gericó MP. [Treatment and prognosis of the severe exacerbation in the chronic obstructive pulmonary disease]. Rev Clin Esp 2001; 201:658-66. [PMID: 11786136 DOI: 10.1016/s0014-2565(01)70941-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wrigge H, Putensen C. What is the "best PEEP" in chronic obstructive pulmonary disease? Intensive Care Med 2000; 26:1167-9. [PMID: 11089736 DOI: 10.1007/s001340000620] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Tassaux D, Jolliet P, Roeseler J, Chevrolet JC. Effects of helium-oxygen on intrinsic positive end-expiratory pressure in intubated and mechanically ventilated patients with severe chronic obstructive pulmonary disease. Crit Care Med 2000; 28:2721-8. [PMID: 10966241 DOI: 10.1097/00003246-200008000-00006] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To test the hypothesis that replacing 70:30 nitrogen: oxygen (Air-O2) with 70:30 helium:oxygen (He-O2) can decrease dynamic hyperinflation ("intrinsic" positive end-expiratory pressure) in mechanically ventilated patients with chronic obstructive pulmonary disease (COPD), and to document the consequences of such an effect on arterial blood gases and hemodynamics. DESIGN Prospective, interventional study. SETTING Medical intensive care unit, university tertiary care center. PATIENTS Twenty-three intubated, sedated, paralyzed, and mechanically ventilated patients with COPD enrolled within 36 hrs after intubation. INTERVENTIONS Measurements were taken at the following time points, all with the same ventilator settings: a) baseline; b) after 45 mins with He-O2; c) 45 mins after return to Air-O2. The results were then compared to those obtained in a test lung model using the same ventilator settings. MAIN RESULTS (MEAN + SD): Trapped lung volume and intrinsic positive end-expiratory pressure decreased during He-O2 ventilation (215+/-125 mL vs. 99+/-15 mL and 9+/-2.5 cm H2O vs. 5+/-2.7 cm H2O, respectively; p < .05). Likewise, peak and mean airway pressures declined with He-O2 (30+/-5 cm H2O vs. 25+/-6 cm H2O and 8+/-2 cm H2O vs. 7+/-2 cm H2O, respectively; p < .05). These parameters all rose to their baseline values on return to Air-O2 (p < .05 vs. values during He-O2). These results were in accordance with those obtained in the test lung model. There was no modification of arterial blood gases, heart rate, or mean systemic arterial blood pressure. In 12/23 patients, a pulmonary artery catheter was in place, allowing hemodynamic measurements and venous admixture calculations. Switching to He-O2 and back to Air-O2 had no effect on pulmonary artery pressures, right and left ventricular filling pressures, cardiac output, pulmonary and systemic vascular resistance, or venous admixture. CONCLUSION In mechanically ventilated COPD patients with intrinsic positive end-expiratory pressure, the use of He-O2 can markedly reduce trapped lung volume, intrinsic positive end-expiratory pressure, and peak and mean airway pressures. No effect was noted on hemodynamics or arterial blood gases. He-O2 might prove beneficial in this setting to reduce the risk of barotrauma, as well as to improve hemodynamics and gas exchange in patients with very high levels of intrinsic positive end-expiratory pressure.
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Affiliation(s)
- D Tassaux
- Medical Intensive Care Division, University Hospital, Geneva, Switzerland
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