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Pre-operative nasal probe tests ease insertion during flexible bronchoscopy and reduce post-operative bleeding: a randomized controlled trial

Zhu, Wenjun1; Zhang, Yuchen2; Shi, Jingyu1; Wang, Xiaoqin1; Li, Renjiao1,2; Liu, Jia1,2; Li, Ping1,2; Liu, Dan1; Luo, Fengming1,2

Editor(s): Wei, Peifang

Author Information
Chinese Medical Journal: July 15, 2022 - Volume - Issue - 10.1097/CM9.0000000000002006
doi: 10.1097/CM9.0000000000002006

Abstract

Introduction

Flexible bronchoscopy is a crucial method widely used in the diagnosis and treatment of pulmonary diseases.[1-4] In recent years, the nasal insertion has become the preferred method for non-intubated spontaneously breathing patients in most centers.[5-7] However, the relatively narrow nasal cavity and fragile nasal mucosa impede insertion, and a quick and blind removal may be necessary.[8] Moreover, the septum is not always located in the middle of the nasal cavity and the nasal passage on both sides is not the same size.[9] Thus, a maneuver to help identify whether or not the bronchoscope can easily pass through the nasal passage is needed.

Bleeding is one of the most concerning complications of bronchoscopy.[10] Fiber-optic endobronchial adrenaline instillation was determined as an effective therapy for air bleeding.[11-13] Topical anesthesia with lidocaine administered through the bronchoscope is a widespread method based on the advantages of better toleration and fewer complications.[14,15] However, data evaluating the combined effect of adrenaline and lidocaine in flexible bronchoscopy with respect to reducing post-operative bleeding and improving the patients’ tolerance are lacking.

Based on these findings, this study aimed to investigate whether pre-operative nasal probe tests could reduce the time to pass the glottis, improve first-pass success rate and the patients’ tolerance, and reduce post-operative bleeding.

Methods

Ethical approval

This single-center randomized controlled trial was designed in accordance with the ethics principles expressed in the Declaration of Helsinki and International Conference on Harmonisation Guidelines for Good Clinical Practice. This study was approved by the Institutional Review Board of West China Hospital, Sichuan University (ethical approval No. 1044). Detailed study protocol could be found in the Supplementary File, https://links.lww.com/CM9/A942. This study was registered at chictr.org.cn (Identifier: ChiCTR2000032668) and was conducted between May and October 2020. Written informed consent was obtained from all the patients before enrolment.

Participants

A total of 300 patients from the Department of Pulmonary and Critical Care Medicine, West China Hospital undergoing flexible bronchoscopy participated in this prospective randomized controlled trial between May and October 2020. Both inpatients and outpatients requiring diagnosis and treatment using flexible bronchoscopy were enrolled.

The inclusion criteria were as follows: (1) having indications of flexible bronchoscopy from respiratory specialists; (2) undergoing flexible bronchoscopy for the first time. The exclusion criteria were: (1) aged < 18 years or > 85 years; (2) having comorbidities such as decompensated heart failure, severe respiratory failure, a history of upper airway surgery or radiation, a bleeding disorder, or mental illness; (3) needing general anesthesia; (4) having nasal diseases that require an orotracheal approach.

Randomization and masking

Eligible patients were simply randomized into the simple cotton bud detection group (CD group), adrenaline + lidocaine detection group (AD group), and control group in a 1:1:1 ratio. A random number was generated via SPSS software (IBM SPSS, version 20, Chicago, IL, USA) by an independent investigator who was not involved in the operation procedure and outcome measurement process. Randomization results were concealed in opaque envelopes and were not revealed until the beginning of the operation. The patient was blinded to the allocation.

Procedures and patient management

Patients in the CD and AD groups underwent nasal probe tests before flexible bronchoscopy to help identify a better nasal passage for inserting the bronchoscope [Supplementary Figure 1, https://links.lww.com/CM9/A942]. Participants in the CD group and the AD group received pre-operative nasal probe tests: using 2 mL of saline (Shijiazhuang No. 4 Pharmaceutical, Shijiazhuang, China) with cotton buds (Chengdu Medical and Sanitary Material Factory, Chengdu, China) for the CD group, and 2 mL ofa mixture of 0.01% adrenaline (GRANDPHARMA, Wuhan, China) and 2% lidocaine (Shanghai Fosun Zhaohui Pharmaceutical, Shanghai, China) with cotton buds for the AD group. The cotton buds were inserted successively through both sides of the nasal cavity to the nasopharynx (using a twisting motion) and kept at the site for at least 2 s. The nasal passage with the least resistance during the probe tests was chosen to perform the flexible bronchoscopy. Participants in the control group were not performed with pre-operative nasal probe tests, and the nasal passage of them was selected randomly.

The procedure of the flexible bronchoscopy was based on the British Thoracic Society guidelines.[16] Briefly, all patients were required to fast for 4–6 h and were initially given 2% lidocaine by nebulized inhalation 30 min before the procedure. Intravenous lines were established after entering the endoscopy room. Vital signs, including blood pressure (BP), heart rate (HR), respiratory rate (RR), and pulse oxygen saturation (SpO2), were continuously monitored by the anesthesiologist and nurse during the flexible bronchoscopy (iPM patient monitor, Shenzhen Mindray Bio-Medical Electronics Co., Ltd, Shenzhen, China). Alarms were set to sound if the SpO2 dropped to <90%, the BP dropped to <90 mmHg, the HR dropped to <40 beats/min, or the RR dropped to <8 breaths/min. Bronchoscopy was performed with a flexible bronchoscope (model BF-1TQ290, Olympus, Tokyo, Japan) with the patient in the supine position. The procedure was performed by two experienced bronchoscopists with relevant professional qualifications and >10 years of practice. During the bronchoscopy, all patients received supplemental oxygen.

Data collection and outcome measurement

Demographics (including age, sex, and body mass index [BMI]) and patients’ disease types were collected at enrolment.

The primary endpoint was the insertion time, defined as the time from touching the nasal ostium to touching the glottis, which was noted with a stopwatch. An independent investigator recorded the insertion time with a stopwatch (measurement accuracy of 0.01 s) and noted whether the first insertion succeeded (recording yes or no). Secondary endpoints included the first-pass success rate, patients’ tolerance scores (including pain, foreign body sensation, and comfort degree), and post-operative complications (including nasal bleeding and the application of hemostatic agents). Pain (0 = non-existent; 100 = unbearable), foreign body sensation (0 = non-existent; 100 = unbearable), and comfort degree (0 = satisfied, feeling nothing; 100 = too uncomfortable to tolerate) were assessed according to the visual analog scale (VAS) within 30 min after the bronchoscopy. A VAS score of the smoothness of the operation of the flexible bronchoscopy was assessed within 30 min after the procedure (5 = smoothest; 0 = unbearable). Moreover, post-operative complications, including nasal bleeding, and the application of hemostatic agents within 24 h after the procedure were recorded.

Sample size calculation

The primary endpoint of this study was the insertion time. A pilot study showed that the hypothesized means ± standard deviations (SDs) of the CD, AD, and control groups were 25 ± 19 s, 24 ± 17 s, and 33 ± 25 s, respectively. At an alpha error of 0.05, we estimated that a sample size of 231 patients (77 patients per group) would provide the trial with 90% power to detect the differences between groups, calculated using PASS 11 (NCSS, Kaysville, UT, USA). In consideration of potential dropouts, 300 patients were enrolled.

Statistical analyses

All statistical analyses were performed using SPSS software (IBM SPSS, version 20, Chicago, IL, USA). Continuous variables in normal and non-normal distribution were presented as means ± SDs or medians (interquartile ranges), respectively. Categorical variables were presented as frequencies and proportions. To analyze the insertion time, tolerance and smoothness scores, and post-operative complications among the three groups, one-way analysis of variance (ANOVA) or Kruskal-Wallis H test was used for continuous variables and Chisquared test or Fisher's exact test was used for categorical variables. Bonferroni's multiple comparison tests were used for multiple group comparisons. Two-tailed P values <0.05 were considered statistically significant.

Results

Demographic and clinical characteristics of participants

Three hundred patients undergoing routine flexible bronchoscopy between May and October 2020 were enrolled after screening for eligibility and were randomly allocated into three groups (each group n = 100) [Figure 1]. In total, 189 men and 111 women were enrolled with a mean age of 55.72 ± 12.86 years. There were no significant differences in age, sex, and BMI among the three groups (all P > 0.05). The distribution of the disease types in the three groups was approximately balanced and did not affect the observation of the outcomes [Table 1].

F1
Figure 1:
Flowchart of patients’ enrolment, allocation, and analysis procedure. AD group: Adrenaline detection group; CD group: Simple cotton bud detection group.
Table 1 - Demographic and clinical characteristics of participants in the three groups.
Variables Control group (n = 100) CD group (n = 100) AD group (n = 100) F/x 2 P values
Age (years) 53.33 ± 14.21 56.54 ± 11.29 57.30 ± 12.70 2.71 0.068
Sex (female/male) 35/65 35/65 41/59 1.03 0.598
BMI (kg/m2) 22.54 ± 3.29 22.43 ± 2.93 22.64 ± 2.99 0.12 0.890
Diseases 21.08 0.275
 COPD 0 (0) 2 (2) 0 (0)
 Space-occupying lesion 55 (55) 65 (65) 58 (58)
 Lung collapse 4 (4) 2 (2) 1 (1)
 Pneumonia 27 (27) 19 (19) 31 (31)
 Lung transplantation 0 (0) 1 (1) 0 (0)
 ILD 1 (1) 2 (2) 1 (1)
 Hemoptysis 7 (7) 2 (2) 1 (1)
 Pleural effusion 1 (1) 2 (2) 4 (4)
 Disease of the trachea 4 (4) 4 (4) 3 (3)
 Others 1 (1) 1 (1) 1 (1)
Data are presented as mean ± standard deviation, n/n or n (%).
Likelihood ratio used.
Including mediastinum space-occupying lesion. AD group: Adrenaline + lidocaine detection group; BMI: Body mass index; CD group: Simple cotton bud detection group; COPD: Chronic obstructive pulmonary disease; ILD: Interstitial lung disease.

Efficiency of nasal probe tests in flexible bronchoscopy

To estimate the efficiency of nasal probe tests, the insertion time and first-pass success rate were assessed by a bronchoscopy specialist. Compared with the control group, the AD group had a significantly shorter time of insertion (18.00 s [12.00–26.50 s] vs. 24.00 s [14.50−45.50 s], P = 0.005). Both the AD (99% vs. 83%, x2 = 15.62, P < 0.001) and CD groups (94% vs.83%, x2 = 5.94, P = 0.015) had a higher first-pass success rate than the control group [Table 2].

Table 2 - Efficiency, post-operative complications and tolerance and smoothness scores of nasal probe tests in flexible bronchoscopy.
Variables Control group (n = 100) CD group (n = 100) AD group (n = 100) H/χ 2 P values
Efficiency
 Insertion time (s) 24.00 (14.50–45.50) 19.50 (12.50–32.50) 18.00 (12.00–26.50) 10.25 0.006
 First-pass success rate 83(83) 94 (94) 99 (99) 18.21 <0.001
Post-operative bleeding and the application of hemostatic agents
 Bleeding 13 (13) 10 (10) 1 (1) , 10.60 0.005
 Hemostatic agents 5 (5) 3 (3) 0 (0) 7.12 0.028
Tolerance and smoothness scores
 Pain 2 (0–5) 1 (0–4) 2 (0–4) 1.98 0.372
 Foreign body sensation 4 (2–6) 3 (2–5) 4 (2–5) 2.27 0.321
 Comfort degree 4 (2–5) 3 (2–5) 3 (2–5) 1.74 0.419
 Smoothness 5 (4–5) 5 (4–5) 5 (4–5) 3.19 0.203
Data are presented as medians (interquartile ranges) or n (%).
P < 0.017 compared with control group with Bonferroni's correction.
P < 0.017 compared with control group with Bonferroni's correction.
Likelihood ratio Chi-square value was used. AD group: Adrenaline+lidocaine detection group; CD group: Simple cotton bud detection group.

Post-operative complications

Compared with patients in the control group, postoperative complications such as bleeding (1% vs. 13%, x2 = 11.06, P < 0.001) and the application of hemostatic agents (0 vs. 5%, x2 = 7.06, P = 0.008) were significantly less common among those in the AD group. When compared with patients in the CD group, those in the AD group were significantly less likely to bleed after the operation (1% vs. 10%, x2 = 7.79, P = 0.005) [Table 2].

Tolerance and smoothness scores

There were no differences in the VAS scores for pain, foreign body sensation, comfort degree toward flexible bronchoscopy, and the smoothness of the operation among the three groups (all P > 0.05) [Table 2].

Safety of nasal probe tests

To estimate the safety of nasal probe tests, patients’ vital signs (including HR, systolic BP, diastolic BP, SpO2, and RR) at three time-points (beginning of the operation, glottis-pass, and at the end of the operation) were collected. There were no significant differences among the groups [Table 3].

Table 3 - Safety estimation of nasal probe tests in patients undergoing flexible bronchoscopy.
Variables Control group (n = 100) CD group (n = 100) AD group (n = 100) H P values
Beginning of the operation
 HR (beats/min) 81.50 (69.50–94.00) 78.50 (68.50–91.50) 80.00 (68.50–92.00) 0.51 0.775
 SBP (mm Hg) 132.00 (118.00–146.00) 131.50 (121.00–145.50) 130.00 (116.00–145.00) 0.04 0.980
 DBP (mm Hg) 82.00 (76.00–89.00) 82.00 (74.00–88.50) 78.00 (71.00–85.50) 5.83 0.054
 SpO2 (%) 98.00 (96.00–99.00) 99.00 (97.00–100.00) 99.00 (96.50–100.00) 3.90 0.142
 RR (breaths/min) 20.00 (20.00–20.00) 20.00 (20.00–21.00) 20.00 (20.00–21.00) 3.68 0.159
Glottis-pass
 HR (beats/min) 90.00 (79.00–103.50) 96.00 (80.50–107.50) 95.00 (78.50–106.50) 0.99 0.610
 SBP (mm Hg) 142.00 (124.00–155.50) 143.50 (122.50–161.50) 138.50 (120.50–158.00) 1.11 0.575
 DBP (mm Hg) 90.50 (81.50–99.00) 92.00 (83.00–102.00) 88.00 (77.50–98.50) 2.46 0.293
 SpO2 (%) 99.00 (96.00–100.00) 99.00 (97.00–100.00) 99.00 (97.00–100.00) 1.99 0.370
 RR (breaths/min) 21.00 (20.00–21.50) 21.00 (20.00–22.00) 21.00 (20.00–22.00) 0.08 0.960
At the end of the operation
 HR (beats/min) 94.50 (81.50–108.50) 92.00 (83.50–104.00) 91.50 (80.50–102.00) 0.57 0.751
 SBP (mm Hg) 137.00 (124.00–148.50) 136.50 (126.50–153.00) 133.50 (120.00–148.50) 1.57 0.456
 DBP (mm Hg) 85.00 (77.50–94.50) 84.00 (76.50–93.00) 82.00 (73.00–89.00) 5.43 0.066
 SpO2 (%) 96.50 (95.00–99.00) 97.00 (95.00–99.00) 97.00 (95.00–99.00) 2.81 0.245
 RR (breaths/min) 21.00 (20.00–21.00) 21.00 (20.00–21.00) 21.00 (20.00–21.00) 0.11 0.948
Data are presented as medians (interquartile ranges). AD group: adrenaline + lidocaine detection group; BP: Blood pressure; CD group: Simple cotton bud detection group; DBP: Diastolic blood pressure; HR: Heart rate; RR: Respiratory rate; SBP: Systolic blood pressure; SpO2: Pulse oxygen saturation.

Discussion

To our knowledge, this is the first three-arm prospective randomized controlled trial to investigate the effect of nasal probe tests used in flexible bronchoscopy with respect to shortening the insertion time, reducing post-operative complications, and improving the patients’ tolerance. For the first time, we identified that probing the nasal cavity with cotton buds before flexible bronchoscopy significantly reduced the time to reach the glottis, improved the first-pass success rate, and reduced post-operative bleeding and the application of hemostatic agents.

In relation to the efficiency of this method, we found that performing nasal probe tests using cotton buds with a mixture of 0.01% adrenaline and 2% lidocaine before flexible bronchoscopy significantly reduced the insertion time and increased the first-pass success rate compared with the conventional approach. Several potential factors can be attributed to these results. First, probing with cotton buds allowed the initial detection of the nasal cavity anatomy. Second, moist cotton buds could lubricate the nasal mucous membranes, which allowed the work channel to easily pass through the nasal passages. Previous studies have confirmed that the median time to reach the glottis with nasal insertion was around 50 s,[17,18] which was much higher than that in our study. The findings of this study confirm the practical value of this method and indicate that the pre-operative detection is of great importance during the process.

Moreover, we determined that the pre-operative nasal probe tests with cotton buds immersed in a mixture of 0.01% adrenaline and 2% lidocaine could reduce postoperative bleeding and the application of hemostatic agents compared with the conventional approach. In general, flexible bronchoscopy is a relatively safe However, no significant difference was identified in terms operation, and the incidence of nasal bleeding after flexible bronchoscopy is currently reported in the literature to be about 0.5%,[19] which is usually small and can be stopped on its own, with the application of 1:10,000 adrenaline to stop the bleeding locally if necessary.[20] Apart from biopsy-related bleeding, the bleeding caused by mechanical friction could cause anxiety and affect the patients’ quality of life.[21] In this study, we found that prior probing was associated with less nasal bleeding and that adrenaline, which reduced the insertion attempts, protected the nasal mucosa, shrunk the capillaries, and reduced the bleeding.[1] of the patients’ tolerance as well as the smoothness of the procedure reported by the bronchoscopist. This may be due to the size of the bronchoscope used in this study. The outer diameter at the distal tip of the bronchoscope was 6.0 mm, which is relatively larger than the standard size of 4.8 mm. This difference may have resulted in increased discomfort experienced by the patients.[22]

To estimate the safety of pre-operative nasal probe tests, we collected several parameters of vital signs at three time-points during the procedure. No significant difference was found among the groups, indicating the relatively safe quality of this method, which could enable its wider application in the future.

In relation to the strengths of this study, this is the first prospective randomized controlled trial to assess the efficiency of pre-operative nasal cavity probe tests. This test is easy to master, economically efficient, and can be applied in other medical procedures, including trans-nasal gastroscopy and nasotracheal intubation. However, this study has some limitations. First, a 6.0 mm bronchoscope was used in this study. Using a bronchoscope with a higher diameter could increase discomfort. There is a need for future studies on a 4.8 mm bronchoscope. Second, since this was a single-center study, these findings may have limited generalizability. Multicenter studies should be conducted to confirm the reliability of these findings in the future.

In conclusion, we recommend nasal probe tests as a timesaving procedure for patients undergoing flexible bronchoscopy as the tests could shorten the time required to reach the glottis and reduce post-operative bleeding.

Availability of data and materials

The datasets analyzed during the current study are available from the corresponding author on reasonable request.

Acknowledgments

The authors thank Prof. Wenjie Yang from the Center of Biostatistics, Design, Measurement and Evaluation (CBDME), West China Hospital for advising on the article revision. The authors thank the patients who took part in the study and the staff of the Department of Pulmonary and Critical Care Medicine, West China Hospital, Sichuan University for their help with data collection.

Funding

This work was supported by grants from the National Natural Science Foundation of China (NSFC No. 81770072); The “1.3.5 project for disciplines of excellence, West China Hospital, Sichuan University (No. ZYJC18021)”; Chengdu Science and Technology Bureau (No. 2018-CY02-00064-GX).

Conflicts of interest

None.

References

1. Du Rand IA, Blaikley J, Booton R, Chaudhuri N, Gupta V, Khalid S, et al. British Thoracic Society guideline for diagnostic flexible bronchoscopy in adults: accredited by NICE. Thorax 2013;68 (Supp 1):i1–i44. doi: 10.1136/thoraxjnl-2013-203618.
2. Casal RF, Ost DE, Eapen GA. Flexible bronchoscopy. Clin Chest Med 2013;34:341–352. doi: 10.1016/j.ccm.2013.03.001.
3. Becker HD. Bronchoscopy: the past, the present, and the future. Clin Chest Med 2010;31:1–18. doi: 10.1016/j.ccm.2009.11.001.
4. Miller RJ, Casal RF, Lazarus DR, Ost DE, Eapen GA. Flexible bronchoscopy. Clin Chest Med 2018;39:1–16. doi: 10.1016/j.ccm.2017.09.002.
5. Wahidi MM, Jain P, Jantz M, Lee P, Mackensen GB, Barbour SY, et al. American college of chest physicians consensus statement on the use of topical anesthesia, analgesia, and sedation during flexible bronchoscopy in adult patients. Chest 2011;140:1342–1350. doi: 10.1378/chest.10-3361.
6. Webb AR, Woodhead MA, Dalton HR, Grigg JA, Millard FJ. Topical nasal anaesthesia for fibreoptic bronchoscopy: patients’ preference for lignocaine gel. Thorax 1989;44:674–675. doi: 10.1136/thx.44.8.674.
7. Zainudin BM, Rafia MH, Sufarlan AW. Topical nasal anaesthesia for fibreoptic bronchoscopy: lignocaine spray or gel? Singapore Med J 1993;34:148–149.
8. Song J. A comparison of the effects of epinephrine and xylometazoline in decreasing nasal bleeding during nasotracheal intubation. J Dent Anesth Pain Med 2017;17:281–287. doi: 10.17245/jdapm.2017.17.4.281.
9. Beeson WH. The nasal septum. Otolaryngol Clin North Am 1987;20:743–767.
10. Faiz SA, Jimenez CA, Fellman BM, Huk T, Jazbeh S, Haque SA, et al. Incidence of bleeding complications with flexible bronchoscopy in cancer patients with thrombocytopenia. J Bronchology Interv Pulmonol 2019;26:280–286. doi: 10.1097/LBR.0000000000000590.
11. Dupree HJ, Lewejohann JC, Gleiss J, Muhl E, Bruch HP. Fiberoptic bronchoscopy of intubated patients with life-threatening hemoptysis. World J Surg 2001;25:104–107. doi: 10.1007/s002680020366.
12. Pu CY, Ivanick N. QA project: hemodynamic safety of endobronchial administration of phenylephrine for control of airway bleeding by bronchoscopy. Pulm Pharmacol Ther 2020;64:101961. doi: 10.1016/j.pupt.2020.101961.
13. Lordan JL, Gascoigne A, Corris PA. The pulmonary physician in critical care ∗ illustrative case 7: assessment and management of massive haemoptysis. Thorax 2003;58:814–819. doi: 10.1136/thorax.58.9.814.
14. Antoniades N, Worsnop C. Topical lidocaine through the bronchoscope reduces cough rate during bronchoscopy. Respirology 2009;14:873–876. doi: 10.1111/j.1440-1843.2009.01587.x.
15. Dreher M, Cornelissen CG, Reddemann MA, Muller A, Hubel C, Muller T. Nebulized versus standard local application of lidocaine during flexible bronchoscopy: a randomized controlled trial. Respiration 2016;92:266–273. doi: 10.1159/000449135.
16. Du Rand IA, Barber PV, Goldring J, Lewis RA, Mandal S, Munavvar M, et al. British Thoracic Society guideline for advanced diagnostic and therapeutic flexible bronchoscopy in adults. Thorax 2011;66:iii1–iii21. doi: 10.1136/thoraxjnl-2011-200713.
17. Aguirre JEG, Martinez UC, Mier DR, Moreno MA, Longoria RM. Bronchoscope insertion route and patient comfort during flexible bronchoscopy. Int J Tuberc Lung Dis 2015;19:356–361. doi: 10.5588/ijtld.14.0632.
18. de Boer GM, Turk Y, Meuleman-van Waning VH, Braunstahl GJ. Bronchoscopy: oral or nasal insertion? J Bronchology Interv Pulmonol 2017;24:125–130. doi: 10.1097/LBR.0000000000000356.
19. de Blic J, Marchac V, Scheinmann P. Complications of flexible bronchoscopy in children: prospective study of 1328 procedures. Eur Respir J 2002;20:1271–1276. doi: 10.1183/09031936.02.02072001.
20. British Thoracic Society Bronchoscopy Guidelines Committee, a Subcommittee of Standards of Care Committee of British Thoracic Society. British Thoracic Society guidelines on diagnostic flexible bronchoscopy. Thorax 2001;56 (Supp 1):i1–i21. doi: 10.5588/ijtld.14.0632.
21. Ata N, Bulbul T, Gokcen C, Demirkan A, Ciftci MA. Depression and anxiety levels in mothers of children with epistaxis: a controlled study. Acta Otorrinolaringol Esp 2019;70:286–289. doi: 10.1016/j.otorri.2018.06.007.
22. Langton D, Gaffney N, Wang WC, Thien F, Plummer V. Utility of a thin bronchoscope in facilitating bronchial thermoplasty. J Asthma Allergy 2018;11:261–266. doi: 10.2147/JAA.S179359.
Keywords:

Complications; Flexible bronchoscopy; Nasal cavity-glottis time; Nasal probe test

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