Abbreviations
- CRD
Centre for Reviews and Dissemination
- MeSH
Medical Subject Headings
- NAC
N-acetylcysteine
- PRISMA
Preferred Reporting Items for Systematic Reviews and Meta-Analyses
Context and Policy Issues
Bronchoscopy is a commonly-used procedure that allows for the visualization of the lungs and air passages using a bronchoscope, a narrow tube with attached lighting and real-time video equipment.1 Bronchoscopy may be performed for several reasons, including the diagnosis of disease (e.g., lung cancer, tuberculosis, pneumonia, infections), foreign body removal, stent insertion, and biopsy.1,2 These procedures may be impeded in cases where the patient is experiencing impaired mucus secretion clearance as a result of various pathologies. Mucolytic agents (a class of drugs which aid in the clearance of mucus in the airways), such as N-acetylcysteine (NAC), may be administered prior to bronchoscopic examination in order to increase visibility and access to the underlying tissue.3,4 NAC’s mechanism of action involves the cleavage of disulfide bonds in heavily cross-linked mucus glycoproteins, resulting in decreased mucus viscosity, thereby facilitating its clearance.5,6
The purpose of the current report is to evaluate the clinical effectiveness and evidence-based guidelines regarding NAC instillation during bronchoscopy for non-cystic fibrosis patients requiring mucus secretion clearance. The findings of this review are complimented by two additional reports on the use of NAC in patients requiring mucus secretion clearance (not specific to bronchoscopy), conducted separately by CADTH.7,8
Research Questions
What is comparative clinical effectiveness of N-acetylcysteine instillation versus saline (normal or hypertonic) during bronchoscopy for non-cystic fibrosis patients requiring mucus secretion clearance?
What are the evidence-based guidelines for N-acetylcysteine instillation during bronchoscopy for non-cystic fibrosis patients requiring mucus secretion clearance?
Key Findings
No relevant literature was identified regarding the comparative clinical effectiveness of N-acetylcysteine instillation versus saline (normal or hypertonic) during bronchoscopy for non-cystic fibrosis patients requiring mucus secretion clearance. Additionally, no evidence-based guidelines were identified regarding N-acetylcysteine instillation during bronchoscopy for non-cystic fibrosis patients requiring mucus secretion clearance.
Methods
Literature Search Methods
A limited literature search was conducted by an information specialist on key resources including MEDLINE, Embase, the Cochrane Library, University of York Centre for Reviews and Dissemination (CRD) databases, Canadian and major international health technology agencies, as well as a focused Internet search. The search strategy was comprised of both controlled vocabulary, such as the National Library of Medicine’s MeSH (Medical Subject Headings), and keywords. The main search concepts were acetylcysteine and mucus or mucous secretions. No filters were applied to limit the retrieval by study type. The search was also limited to English language documents published between January 1, 2014 and July 8, 2019.
Selection Criteria and Methods
One reviewer screened citations and selected studies. In the first level of screening, titles and abstracts were reviewed and potentially relevant articles were retrieved and assessed for inclusion. The final selection of full-text articles was based on the inclusion criteria presented in .
Exclusion Criteria
Articles were excluded if they did not meet the selection criteria outlined in , they were duplicate publications, or were published prior to 2014. Guidelines with unclear methodology were also excluded.
Summary of Evidence
Quantity of Research Available
A total of 374 citations were identified in the literature search. Following screening of titles and abstracts, 359 citations were excluded and 15 potentially relevant reports from the electronic search were retrieved for full-text review. In addition, one potentially relevant publication was retrieved from the grey literature search for full-text review. Of these 16 potentially relevant articles, all were excluded for various reasons; no publications met the inclusion criteria and were included in this report. Appendix 1 presents the PRISMA9 flowchart of the study selection. References of potential interest are provided in Appendix 2.
Summary of Findings
No relevant literature was identified regarding NAC instillation during bronchoscopy for non-cystic fibrosis patients requiring mucus secretion clearance; therefore, no summary can be provided.
Limitations
No relevant literature was identified regarding the clinical effectiveness of NAC instillation versus saline (normal or hypertonic) during bronchoscopy for non-cystic fibrosis patients requiring mucus secretion clearance. Additionally, no evidence-based guidelines were identified regarding NAC instillation during bronchoscopy for non-cystic fibrosis patients requiring mucus secretion clearance. This report is limited by the timeframe used for literature searches (extended only to 2014); it is possible that relevant literature was published more than five years ago and was excluded by the current date-limited search.
Conclusions and Implications for Decision or Policy Making
No relevant literature or evidence-based guidelines were identified regarding NAC instillation during bronchoscopy for non-cystic fibrosis patients requiring mucus secretion clearance; therefore, no conclusions regarding the clinical effectiveness or evidence-based guidelines can be provided.
Research examining the comparative clinical effectiveness of NAC instillation during bronchoscopy for non-cystic fibrosis patients is required in order to investigate this potential application of NAC. The lack of published evidence precludes the creation of appropriate guidelines for health care providers who perform bronchoscopy in this patient population.
References
- 1.
- 2.
- 3.
Millman
M, Goodman
AH, Goldstein
IM, Millman
FM, Van Campen
SS. Status Asthmaticus: use of acetylcysteine during bronchoscopy and lavage to remove mucous plugs.
Ann Allergy. 1983;50(2):85–93. [
PubMed: 6824202]
- 4.
Mata
AF, Sarnaik
AA. Bronchoscopy With N-Acetylcysteine Lavage in Severe Respiratory Failure From Pertussis Infection.
Pediatrics. 2013;132(5):e1418–e1423. [
PubMed: 24167177]
- 5.
Sathe
NA, Krishnaswami
S, Andrews
J, Ficzere
C, McPheeters
ML. Pharmacologic Agents That Promote Airway Clearance in Hospitalized Subjects: A Systematic Review.
Respir Care. 2015;60(7):1061–1070. [
PubMed: 25944943]
- 6.
Aldini
G, Altomare
A, Baron
G, et al. N-Acetylcysteine as an antioxidant and disulphide breaking agent: the reasons why.
Free Radic Res. 2018;52(7):751–762. [
PubMed: 29742938]
- 7.
- 8.
- 9.
Liberati
A, Altman
DG, Tetzlaff
J, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration.
J Clin Epidemiol. 2009;62(10):e1–e34. [
PubMed: 19631507]
Appendix 1. Selection of Included Studies
Appendix 2. Additional References of Potential Interest
Systematic Reviews and Meta-Analyses
Alternative Population - Patients Not Undergoing Bronchoscopy
Tarrant
BJ, Le Maitre
C, Romero
L, et al. Mucoactive agents for chronic, non-cystic fibrosis lung disease: A systematic review and meta-analysis.
Respirology. 2017
08;22(6):1084–1092.
PubMed: PM28397992 [
PubMed: 28397992]
About the Series
CADTH Rapid Response Report: Summary with Critical Appraisal
Funding: CADTH receives funding from Canada’s federal, provincial, and territorial governments, with the exception of Quebec.
Suggested citation:
N-Acetylcysteine Instillation During Bronchoscopy for Patients Requiring Non-Cystic Fibrosis-Related Mucus Secretion Clearance: A Review of Clinical Effectiveness and Guidelines. Ottawa: CADTH; 2019 Aug. (CADTH rapid response report: summary with critical appraisal).
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