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Brown LK. Targeting Hypercapnia in Chronic Lung Disease and Obesity Hypoventilation: Benefits and Challenges. Sleep Med Clin 2024; 19:357-369. [PMID: 38692758 DOI: 10.1016/j.jsmc.2024.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
Hypoventilation is a complication that is not uncommon in chronic obstructive pulmonary disease and calls for both medical treatment of the underlying disease and, frequently, noninvasive ventilation either during exacerbations requiring hospitalization or in a chronic state in the patient at home. Obesity hypoventilation syndrome by definition is associated with ventilatory failure and hypercapnia. It may or may not be accompanied by obstructive sleep apnea, which when detected becomes an additional target for positive airway pressure treatment. Intensive research has not completely resolved the best choice of treatment, and the simplest modality, continuous positive airway pressure, may still be entertained.
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Affiliation(s)
- Lee K Brown
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, USA.
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Bemand TJ, Chatoor R, Natale P, Strippoli G, Delaney A. Acetazolamide for metabolic alkalosis complicating respiratory failure with chronic obstructive pulmonary disease or obesity hypoventilation syndrome: a systematic review. Thorax 2023; 78:1004-1010. [PMID: 37217290 DOI: 10.1136/thorax-2023-219988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 03/03/2023] [Indexed: 05/24/2023]
Abstract
BACKGROUND Metabolic alkalosis may lead to respiratory inhibition and increased need for ventilatory support or prolongation of weaning from ventilation for patients with chronic respiratory disease. Acetazolamide can reduce alkalaemia and may reduce respiratory depression. METHODS We searched Medline, EMBASE and CENTRAL from inception to March 2022 for randomised controlled trials comparing acetazolamide to placebo in patients with chronic obstructive pulmonary disease, obesity hypoventilation syndrome or obstructive sleep apnoea, hospitalised with acute respiratory deterioration complicated by metabolic alkalosis. The primary outcome was mortality and we pooled data using random-effects meta-analysis. Risk of bias was assessed using the Cochrane RoB 2 (Risk of Bias 2) tool, heterogeneity was assessed using the I2 value and χ2 test for heterogeneity. Certainty of evidence was assessed using GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) methodology. RESULTS Four studies with 504 patients were included. 99% of included patients had chronic obstructive pulmonary disease. No trials recruited patients with obstructive sleep apnoea. 50% of trials recruited patients requiring mechanical ventilation. Risk of bias was overall low to some risk. There was no statistically significant difference with acetazolamide in mortality (relative risk 0.98 (95% CI 0.28 to 3.46); p=0.95; 490 participants; three studies; GRADE low certainty) or duration of ventilatory support (mean difference -0.8 days (95% CI -7.2 to 5.6); p=0.36; 427 participants; two studies; GRADE: low certainty). CONCLUSION Acetazolamide may have little impact on respiratory failure with metabolic alkalosis in patients with chronic respiratory diseases. However, clinically significant benefits or harms are unable to be excluded, and larger trials are required. PROSPERO REGISTRATION NUMBER CRD42021278757.
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Affiliation(s)
- Timothy John Bemand
- Wagga Wagga Base Hospital, Wagga Wagga, New South Wales, Australia
- Rural Clinical School Wagga Wagga Campus, University of New South Wales, Wagga Wagga, New South Wales, Australia
- Sydney School of Public Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Richard Chatoor
- Wagga Wagga Base Hospital, Wagga Wagga, New South Wales, Australia
- Rural Clinical School Wagga Wagga Campus, University of New South Wales, Wagga Wagga, New South Wales, Australia
- Malcolm Fisher Department of Intensive Care Medicine, Royal North Shore Hospital, St Leonards, New South Wales, Australia
| | - Patrizia Natale
- Sydney School of Public Health, The University of Sydney, Sydney, New South Wales, Australia
- Department of Precision and Regenerative Medicine and Ionian Area (DIMEPRE-J), University of Bari Aldo Moro, Bari, Italy
- Nephrology, Dialysis and Transplantation Unit, Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Giovanni Strippoli
- Sydney School of Public Health, The University of Sydney, Sydney, New South Wales, Australia
- Department of Precision and Regenerative Medicine and Ionian Area (DIMEPRE-J), University of Bari Aldo Moro, Bari, Italy
| | - Anthony Delaney
- Malcolm Fisher Department of Intensive Care Medicine, Royal North Shore Hospital, St Leonards, New South Wales, Australia
- Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- Division of Critical Care, The George Institute for Global Health, Newtown, New South Wales, Australia
- Department of Epidemiology and Preventative Medicine, Monash University, ANZIC-RC, Melbourne, Victoria, Australia
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Yi Y. Post-Hypercapnic Alkalosis: A Brief Review. Electrolyte Blood Press 2023; 21:18-23. [PMID: 37434801 PMCID: PMC10329906 DOI: 10.5049/ebp.2023.21.1.18] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/17/2023] [Accepted: 04/25/2023] [Indexed: 07/13/2023] Open
Abstract
Metabolic alkalosis is a common acid-base imbalance frequently observed in intensive care unit (ICU) patients and is associated with increased mortality. Post-hypercarbia alkalosis (PHA) is a type of metabolic alkalosis caused by sustained high serum bicarbonate levels following a rapid resolution of hypoventilation in patients with chronic hypercapnia due to prolonged respiratory disturbance. Common causes of chronic hypercapnia include chronic obstructive pulmonary disease (COPD), central nervous system disorders, neuromuscular disorders, and narcotic abuse. Rapid correction of hypercapnia through hyperventilation leads to a swift normalization of pCO2, which lacks renal compensation, consequently causing an increase in plasma HCO3- levels and severe metabolic alkalosis. Most of PHA occurs in the ICU setting requiring mechanical ventilation and can progress severe alkalemia due to secondary mineralocorticoid excess from volume depletion or decreased HCO3- excretion from decreased glomerular filtration rate and increased proximal tubular reabsorption. PHA is associated with increased ICU stay, ventilator dependency, and mortality. Acetazolamide, a carbonic anhydrase inhibitor, has been utilized for managing PHA by inducing alkaline diuresis and reducing tubular reabsorption of bicarbonate. While acetazolamide effectively improves alkalemia, its impact on hard outcomes may be limited by factors such as patient complexity, co-administered medications, and underlying conditions contributing to alkalosis.
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Affiliation(s)
- Yongjin Yi
- Division of Nephrology, Department of Internal Medicine, Dankook University Hospital, Dankook University College of Medicine, Cheonan, Republic of Korea
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Schönhofer B, Geiseler J, Dellweg D, Fuchs H, Moerer O, Weber-Carstens S, Westhoff M, Windisch W. Prolonged Weaning: S2k Guideline Published by the German Respiratory Society. Respiration 2020; 99:1-102. [PMID: 33302267 DOI: 10.1159/000510085] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 07/09/2020] [Indexed: 01/28/2023] Open
Abstract
Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by respiratory muscle insufficiency and/or lung parenchymal disease; that is, when other treatments such as medication, oxygen administration, secretion management, continuous positive airway pressure (CPAP), or nasal high-flow therapy have failed. MV is required for maintaining gas exchange and allows more time to curatively treat the underlying cause of respiratory failure. In the majority of ventilated patients, liberation or "weaning" from MV is routine, without the occurrence of any major problems. However, approximately 20% of patients require ongoing MV, despite amelioration of the conditions that precipitated the need for it in the first place. Approximately 40-50% of the time spent on MV is required to liberate the patient from the ventilator, a process called "weaning". In addition to acute respiratory failure, numerous factors can influence the duration and success rate of the weaning process; these include age, comorbidities, and conditions and complications acquired during the ICU stay. According to international consensus, "prolonged weaning" is defined as the weaning process in patients who have failed at least 3 weaning attempts, or require more than 7 days of weaning after the first spontaneous breathing trial (SBT). Given that prolonged weaning is a complex process, an interdisciplinary approach is essential for it to be successful. In specialised weaning centres, approximately 50% of patients with initial weaning failure can be liberated from MV after prolonged weaning. However, the heterogeneity of patients undergoing prolonged weaning precludes the direct comparison of individual centres. Patients with persistent weaning failure either die during the weaning process, or are discharged back to their home or to a long-term care facility with ongoing MV. Urged by the growing importance of prolonged weaning, this Sk2 Guideline was first published in 2014 as an initiative of the German Respiratory Society (DGP), in conjunction with other scientific societies involved in prolonged weaning. The emergence of new research, clinical study findings and registry data, as well as the accumulation of experience in daily practice, have made the revision of this guideline necessary. The following topics are dealt with in the present guideline: Definitions, epidemiology, weaning categories, underlying pathophysiology, prevention of prolonged weaning, treatment strategies in prolonged weaning, the weaning unit, discharge from hospital on MV, and recommendations for end-of-life decisions. Special emphasis was placed on the following themes: (1) A new classification of patient sub-groups in prolonged weaning. (2) Important aspects of pulmonary rehabilitation and neurorehabilitation in prolonged weaning. (3) Infrastructure and process organisation in the care of patients in prolonged weaning based on a continuous treatment concept. (4) Changes in therapeutic goals and communication with relatives. Aspects of paediatric weaning are addressed separately within individual chapters. The main aim of the revised guideline was to summarize both current evidence and expert-based knowledge on the topic of "prolonged weaning", and to use this information as a foundation for formulating recommendations related to "prolonged weaning", not only in acute medicine but also in the field of chronic intensive care medicine. The following professionals served as important addressees for this guideline: intensivists, pulmonary medicine specialists, anaesthesiologists, internists, cardiologists, surgeons, neurologists, paediatricians, geriatricians, palliative care clinicians, rehabilitation physicians, intensive/chronic care nurses, physiotherapists, respiratory therapists, speech therapists, medical service of health insurance, and associated ventilator manufacturers.
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Affiliation(s)
- Bernd Schönhofer
- Klinikum Agnes Karll Krankenhaus, Klinikum Region Hannover, Laatzen, Germany,
| | - Jens Geiseler
- Klinikum Vest, Medizinische Klinik IV: Pneumologie, Beatmungs- und Schlafmedizin, Marl, Germany
| | - Dominic Dellweg
- Fachkrankenhaus Kloster Grafschaft GmbH, Abteilung Pneumologie II, Schmallenberg, Germany
| | - Hans Fuchs
- Universitätsklinikum Freiburg, Zentrum für Kinder- und Jugendmedizin, Neonatologie und Pädiatrische Intensivmedizin, Freiburg, Germany
| | - Onnen Moerer
- Universitätsmedizin Göttingen, Klinik für Anästhesiologie, Göttingen, Germany
| | - Steffen Weber-Carstens
- Charité, Universitätsmedizin Berlin, Klinik für Anästhesiologie mit Schwerpunkt operative Intensivmedizin, Campus Virchow-Klinikum und Campus Mitte, Berlin, Germany
| | - Michael Westhoff
- Lungenklinik Hemer, Hemer, Germany
- Universität Witten/Herdecke, Herdecke, Germany
| | - Wolfram Windisch
- Lungenklinik, Kliniken der Stadt Köln gGmbH, Universität Witten/Herdecke, Herdecke, Germany
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Teppema LJ, Boulet LM, Hackett HK, Dominelli PB, Cheyne WS, Dominelli GS, Swenson ER, Foster GE. Influence of methazolamide on the human control of breathing: A comparison to acetazolamide. Exp Physiol 2019; 105:293-301. [PMID: 31595565 DOI: 10.1113/ep088058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/04/2019] [Indexed: 01/15/2023]
Abstract
NEW FINDINGS What is the central question of this study? Acetazolamide and methazolamide both reduce hypoxic pulmonary vasoconstriction equally, but methazolamide does not impair skeletal muscle function. The effect of methazolamide on respiratory control in humans is not yet known. What is the main finding and its importance? Similar to acetazolamide after chronic oral administration, methazolamide causes a metabolic acidosis and shifts the ventilatory CO2 response curve leftwards without reducing O2 sensitivity. The change in ventilation over the change in log P O 2 provides a more accurate measure of hypoxic sensitivity than the change in ventilation over the change in arterial oxyhaemoglobin saturation. ABSTRACT Acetazolamide is used to prevent/treat acute mountain sickness and both central and obstructive sleep apnoea. Methazolamide, like acetazolamide, reduces hypoxic pulmonary vasoconstriction, but has fewer side-effects, including less impairment of skeletal muscle function. Given that the effects of methazolamide on respiratory control in humans are unknown, we compared the effects of oral methazolamide and acetazolamide on ventilatory control and determined the ventilation-log P O 2 relationship in humans. In a double-blind, placebo-controlled, randomized cross-over design, we studied the effects of acetazolamide (250 mg three times daily), methazolamide (100 mg twice daily) and placebo in 14 young male subjects who were exposed to 7 min of normoxic hypercapnia and to three levels of eucapnia and hypercapnic hypoxia. With placebo, methazolamide and acetazolamide, the CO2 sensitivities were 2.39 ± 1.29, 3.27 ± 1.82 and 2.62 ± 1.79 l min-1 mmHg-1 (n.s.) and estimated apnoeic thresholds 32 ± 3, 28 ± 3 and 26 ± 3 mmHg, respectively (P < 0.001, placebo versus methazolamide and acetazolamide). The relationship between ventilation ( V ̇ I ) and log P O 2 (using arterialized venous P O 2 in hypoxia) was linear, and neither agent influenced the relationship between hypoxic sensitivity ( Δ V ̇ I / Δ log P O 2 ) and arterial [H+ ]. Using Δ V ̇ I / Δ log P O 2 rather than Δ V ̇ I /Δ arterial oxyhaemoglobin saturation enables a more accurate estimation of oxygenation and ventilatory control in metabolic acidosis/alkalosis when right- or leftward shifts of the oxyhaemoglobin saturation curve occur. Given that acetazolamide and methazolamide have similar effects on ventilatory control, methazolamide might be preferred for indications requiring the use of a carbonic anhydrase inhibitor, avoiding some of the negative side-effects of acetazolamide.
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Affiliation(s)
- Luc J Teppema
- Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Lindsey M Boulet
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada
| | - Heather K Hackett
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada
| | - Paolo B Dominelli
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada.,Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
| | - William S Cheyne
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada
| | - Giulio S Dominelli
- Southern Medical Program, University of British Columbia, Kelowna, BC, Canada
| | - Erik R Swenson
- Division of Pulmonary & Critical Care Medicine, VA Puget Sound Health Care System, University of Washington, Seattle, WA, USA
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada
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McCoy IE, Chertow GM, Chang TIH. Patterns of diuretic use in the intensive care unit. PLoS One 2019; 14:e0217911. [PMID: 31150512 PMCID: PMC6544280 DOI: 10.1371/journal.pone.0217911] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 05/21/2019] [Indexed: 02/07/2023] Open
Abstract
Purpose To inform future outcomes research on diuretics, we sought to describe modern patterns of diuretic use in the intensive care unit (ICU), including diuretic type, combination, and dosing. We also investigated two possible quality improvement targets: furosemide dosing in renal impairment and inclusion of an initial bolus with continuous furosemide infusions. Materials and methods In this descriptive study, we retrospectively studied 46,037 adult ICU admissions from a publicly available database of patients in an urban, academic medical center. Results Diuretics were employed in nearly half (49%, 22,569/46,037) of ICU admissions. Mechanical ventilation, a history of heart failure, and admission to the post-cardiac surgery unit were associated with a higher frequency of diuretic use. Combination use of different diuretic classes was uncommon. Patients with severely impaired kidney function were less likely to receive diuretics. Furosemide was by far the most common diuretic given and the initial intravenous dose was only 20 mg in more than half of ICU admissions. Among patients treated with a continuous infusion, 30% did not receive a bolus on the day of infusion initiation. Conclusions Patterns of diuretic use varied by patient-specific factors and by ICU type. Diuretic dosing strategies may be suboptimal.
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Affiliation(s)
- Ian Ellis McCoy
- Division of Nephrology, Stanford University School of Medicine, Palo Alto, California
- * E-mail:
| | - Glenn Matthew Chertow
- Division of Nephrology, Stanford University School of Medicine, Palo Alto, California
| | - Tara I-Hsin Chang
- Division of Nephrology, Stanford University School of Medicine, Palo Alto, California
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Tanios BY, Omran MO, Noujeim C, Lotfi T, Mallat SS, Bou-Khalil PK, Akl EA, Itani HS. Carbonic anhydrase inhibitors in patients with respiratory failure and metabolic alkalosis: a systematic review and meta-analysis of randomized controlled trials. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2018; 22:275. [PMID: 30371345 PMCID: PMC6205780 DOI: 10.1186/s13054-018-2207-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/24/2018] [Indexed: 11/22/2022]
Abstract
Background Metabolic alkalosis is common in patients with respiratory failure and may delay weaning in mechanically ventilated patients. Carbonic anhydrase inhibitors block renal bicarbonate reabsorption, and thus reverse metabolic alkalosis. The objective of this systematic review is to assess the benefits and harms of carbonic anhydrase inhibitor therapy in patients with respiratory failure and metabolic alkalosis. Methods We searched the following electronic sources from inception to August 2017: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and SCOPUS. Randomized clinical trials were included if they assessed at least one of the following outcomes: mortality, duration of hospital stay, duration of mechanical ventilation, adverse events, and blood gas parameters. Teams of two review authors worked in an independent and duplicate manner to select eligible trials, extract data, and assess risk of bias of the included trials. We used meta-analysis to synthesize statistical data and then assessed the certainty of evidence using the GRADE methodology. Results Six eligible studies were identified with a total of 564 participants. The synthesized data did not exclude a reduction or an increase in mortality (risk ratio (RR) 0.94, 95% confidence interval (CI) 0.57 to 1.56) or in duration of hospital stay (mean difference (MD) 0.42 days, 95% CI −4.82 to 5.66) with the use of carbonic anhydrase inhibitors. Carbonic anhydrase inhibitor therapy resulted in a decrease in the duration of mechanical ventilation of 27 h (95% CI −50 to −4). Also, it resulted in an increase in PaO2 (MD 11.37 mmHg, 95% CI 4.18 to 18.56) and a decrease in PaCO2 (MD −4.98 mmHg, 95% CI −9.66, −0.3), serum bicarbonate (MD −5.03 meq/L, 95% CI −6.52 to −3.54), and pH (MD −0.04, 95% CI −0.07 to −0.01). There was an increased risk of adverse events in the carbonic anhydrase inhibitor group (RR 1.71, 95% CI 0.98 to 2.99). Certainty of evidence was judged to be low for most outcomes. Conclusion In patients with respiratory failure and metabolic alkalosis, carbonic anhydrase inhibitor therapy may have favorable effects on blood gas parameters. In mechanically ventilated patients, carbonic anhydrase inhibitor therapy may decrease the duration of mechanical ventilation. A major limitation of this finding was that only two trials assessed this clinically important outcome. Electronic supplementary material The online version of this article (10.1186/s13054-018-2207-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bassem Y Tanios
- Division of Nephrology and Hypertension, American University of Beirut Medical Center, Beirut, Lebanon
| | - Maryam O Omran
- Faculty of Health Sciences, American University of Beirut, Beirut, Lebanon
| | - Carlos Noujeim
- Division of pulmonary and critical care, Keserwan Medical Center, Ghazir, Lebanon
| | - Tamara Lotfi
- Clinical Research Institute, and Faculty of Health Sciences, American University of Beirut, Beirut, Lebanon
| | - Samir S Mallat
- Division of Nephrology and Hypertension, American University of Beirut Medical Center, Beirut, Lebanon. .,Department of Internal Medicine, American University of Beirut Medical Center, PO Box 11-0236, Riad El-Solh, Beirut, 1107 2020, Lebanon.
| | - Pierre K Bou-Khalil
- Division of Pulmonary and Critical Care, American University of Beirut Medical Center, Beirut, Lebanon. .,Department of Internal Medicine, American University of Beirut Medical Center, PO Box 11-0236, Riad El-Solh, Beirut, 1107 2020, Lebanon.
| | - Elie A Akl
- Department of Internal Medicine, American University of Beirut, Beirut, Lebanon
| | - Houssam S Itani
- Division of Nephrology and Hypertension, Makassed General Hospital, Beirut, Lebanon
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Bahloul M, Ammar R, Bouattour A, Bellil S, Chelly H, Chaari A, Bouaziz M. Effects of early administration of acetazolamide on the duration of mechanical ventilation in patients with chronic obstructive pulmonary disease: still far from the truth? J Thorac Dis 2017; 9:1393-1395. [PMID: 28740640 DOI: 10.21037/jtd.2017.05.41] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Mabrouk Bahloul
- Department of Intensive Care, Habib Bourguiba University Hospital, Sfax, Tunisia
| | - Rania Ammar
- Department of Intensive Care, Habib Bourguiba University Hospital, Sfax, Tunisia
| | - Abir Bouattour
- Department of Intensive Care, Habib Bourguiba University Hospital, Sfax, Tunisia
| | - Samar Bellil
- Department of Intensive Care, Habib Bourguiba University Hospital, Sfax, Tunisia
| | - Hedi Chelly
- Department of Intensive Care, Habib Bourguiba University Hospital, Sfax, Tunisia
| | - Anis Chaari
- Department of Intensive Care, Habib Bourguiba University Hospital, Sfax, Tunisia
| | - Mounir Bouaziz
- Department of Intensive Care, Habib Bourguiba University Hospital, Sfax, Tunisia
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Jones PW, Greenstone M. Carbonic anhydrase inhibitors for hypercapnic ventilatory failure in chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2001; 2001:CD002881. [PMID: 11279770 PMCID: PMC6483619 DOI: 10.1002/14651858.cd002881] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Carbonic anhydrase inhibitors such as acetazolamide cause a mild metabolic acidosis and may stimulate breathing. Some patients with severe chronic obstructive pulmonary disease (COPD) develop chronic hypercapnic ventilatory failure. In theory, they may benefit from use of these drugs with a fall in arterial carbon dioxide level (PCO2) and a rise in arterial oxygen (PO2). OBJECTIVES To determine the effectiveness and safety of acetazolamide in the treatment of hypercapnic ventilatory failure due to COPD SEARCH STRATEGY: The Cochrane Register of Controlled Clinical Trials was searched along with Medline, Embase, Central and CINAHL for relevant randomised control trials. SELECTION CRITERIA Trials were included in the review provided they were placebo controlled, carried out in patients with stable chronic ventilatory failure due to COPD. DATA COLLECTION AND ANALYSIS Data were extracted and analysed by two reviewers (PJ and MG) and agreement was reached by consensus. Where data could be aggregated they were analysed using a fixed efefcts model and reported as a weighted mean difference (WMD) and its associated 95% confidence interval (95% CI). MAIN RESULTS Four trials were included in the review. Of these, two were randomised parallel studies, one was a crossover study and the other had a sequential design. A total of 84 patients were involved. Study quality was mixed and the studies were short (typically two weeks). All studies showed a similar direction and size of effect. In the randomised parallel studies, acetazolamide caused a metabolic acidosis and produced a non-significant fall in PCO2 (WMD -0.41 kPa; 95% CI -0.91, 0.09; N=2) and a significant rise in PO2 (WMD 1.54 kPa; 95% CI 0.97, 2.11; N=2). One study reported an improvement in sleep but there were no data concerning outcomes such as health status, symptoms, exacerbation rate, hospital admissions or deaths. Side effects were reported infrequently. REVIEWER'S CONCLUSIONS Acetazolamide can produce a small increase in arterial PO2 and fall in PCO2. These conclusions are drawn from a few small short studies that were not all of high quality. It is not known whether this physiological improvement is associated with clinical benefit.
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Affiliation(s)
- P W Jones
- Division of Physiological Medicine, St George's Hospital Medical School, Cranmer Terrace, Tooting, London, UK, SW17 ORE.
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