Nasal Probe Tests Decreased the Procedure Time During Flexible Bronchoscopy: A Randomized Controlled Trial

Background: Nasal insertion is the preferred method in exible bronchoscopy; however, the relatively narrow nasal cavity increases the diculty of bronchoscope insertion. The aim of the study was to investigate the advantages of a prior nasal cavity probe during exible bronchoscopy and to investigate whether this novel method could reduce the complications associated with exible bronchoscopy. Methods: This prospective randomized controlled trial was conducted in a tertiary hospital between May 2020 and October 2020. Three hundred patients requiring diagnosis and treatment using exible bronchoscopy were randomly allocated to three groups: a control group, a simple cotton bud detection group (CD group), and an adrenaline detection group (AD group). The outcomes were the time to pass the glottis, the rst-pass intubation success rate, and postoperative complications, especially nasal bleeding. Results: In total, 189 men and 111 women were enrolled in the study, with a mean age of 55.69 ± 12.86 years. The operation time was longer in the control group (24 [14.25-45.75] s) than in the CD group (19.5 [12.25-32.75] s). Compared with that in the CD group, the rst-pass intubation success rate was signicantly lower in the control group (p<0.05). There was no difference in nasal bleeding between the control group and the CD group (p=0.506). Nasal bleeding after exible bronchoscopy was more common in the CD group than in the AD group (p=0.005); however, there was no signicant between-group difference in hemostatic use (p=0.245). Conclusions: Use of a prior nasal cavity probe during exible bronchoscopy can signicantly reduce the time to pass the nasal cavity, improve the rst-pass intubation success rate, and reduce postoperative nasal bleeding. Nasal detection is recommended as a time-saving procedure for patients undergoing exible bronchoscopy. Trial

years. The operation time was longer in the control group (24 [14.25-45.75] s) than in the CD group (19.5 [12.25-32.75] s). Compared with that in the CD group, the rst-pass intubation success rate was signi cantly lower in the control group (p<0.05). There was no difference in nasal bleeding between the control group and the CD group (p=0.506). Nasal bleeding after exible bronchoscopy was more common in the CD group than in the AD group (p=0.005); however, there was no signi cant between-group difference in hemostatic use (p=0.245).
Conclusions: Use of a prior nasal cavity probe during exible bronchoscopy can signi cantly reduce the time to pass the nasal cavity, improve the rst-pass intubation success rate, and reduce postoperative nasal bleeding. Nasal detection is recommended as a time-saving procedure for patients undergoing exible bronchoscopy.

Background
Flexible bronchoscopy is a crucial method used in the diagnosis and treatment of pulmonary diseases that is widely used in hospitals, especially in the respiratory department. 1 Nasal and oral insertion are the two most common approaches in clinical practice, with nasal insertion being preferred due to its advantages with respect to its simplicity, time-saving nature, and fewer complications. 2 Topical lidocaine administered through the bronchoscope is better-tolerated with fewer complications, which contributes to the widespread use of topical anesthesia during exible bronchoscopy. [3][4][5] Although there have been several measures for improving patient comfort during the exible bronchoscopy procedure, the relatively narrow nasal cavity and fragile nasal mucosa impede insertion, and a quick and blind removal may be necessary. 6 The septum is not always located in the middle of the nasal cavity; moreover, the nasal passages on both sides are not of the exact same size. 7 Therefore, the aim of the study was to investigate the superiority of prior probing of the nasal cavity during exible bronchoscopy and to examine if this novel method could reduce the complications associated with exible bronchoscopy.

Methods
This prospective randomized controlled trial was conducted in the Department of Pulmonary and Critical Care Medicine, West China Hospital of Sichuan University between May 2020 and October 2020 (chictr.org.cn,Identi er:ChiCTR2000032668). We enrolled inpatients and outpatients who required diagnosis and treatment using exible bronchoscopy. The inclusion criteria were (1) diagnosis by a respiratory specialist with exible bronchoscopy indications and (2) undergoing exible bronchoscopy for the rst time. The exclusion criteria were (1) aged < 18 years or > 85 years; (2) having decompensated heart failure, severe respiratory failure, history of upper airway surgery or radiation, a bleeding disorder, or mental illness; (3) requiring general anesthesia; and (4) having nasal disease requiring the orotracheal approach. This study was approved by the ethics committee of West China Hospital (Ethical approval No. 1044) and all the patients provided informed consent for voluntary study participation.
At enrollment, we collected the main demographics and clinical data of all patients. As per the protocol, all patients were required to fast for 4-6 hours before examination. Further, intravenous lines were established after entering the endoscopy room. Vital signs, including blood pressure, heart rate, and pulse oxygen saturation, were continuously monitored by the anesthesiologist and nurse during the exible bronchoscopy. All patients received topical anesthesia using 2% lidocaine. Subsequently, the patients were allocated to the different study groups according to a computer-generated random number. In the control group, the bronchoscopy specialist chose the approach for exible bronchoscopy according to experience and routine observation. In the simple cotton bud detection group (CD group), cotton buds with saline were used to probe the nasal cavity for a better approach. The nasal cavities on both sides were probed successively where the cotton bud was rst inserted into the nasal cavity on the side with the least resistance. In the adrenaline detection group (AD group), cotton buds with a mixture of 1‱ adrenaline and 2% lidocaine were used to probe the nasal cavity for a better approach. All patients were unaware of the group allocation.
A bronchoscopy specialist used a BF-1TQ290 electronic bronchoscope (Olympus Optical Co., Tokyo, Japan) with an outer diameter of 6 mm to perform all the bronchoscopy procedures. Figure 1 shows the detailed procedural protocols and the relevant guidelines have been described previously 8 .
At the end of the exible bronchoscopy procedure, the operation time (from touching of the nasal ostium to the touching of the glottis) was recorded. Moreover, the number of operations required for a successful procedure was recorded. In case the initial attempt for operators to reach the glottis through one nasal cavity side succeeded, the number of operations was recorded as one. If it failed on one side and succeeded on the other, the number of operations was recorded as two. Moreover, postoperative complications, including nasal bleeding and hemostatic use, were ascertained upon completion of the exible bronchoscopy.
Upon bronchoscopy completion, each patient was encouraged to ll a visual analog scale (VAS) to provide a rough estimate of pain, nasal foreign body sensation, and degree of comfort, with a maximum score of 100. Moreover, the operator lled out a 5-point VAS to assess the process of exible bronchoscopy with 5 points indicating extremely successful.

Statistical analysis
All statistical analyses were performed using SPSS software (IBM SPSS, version 20, Chicago, IL). Data were presented as mean ± SD or as a count (percentage). Intergroup comparison was performed using the independent-sample t test, analysis of variance, Mann-Whitney U test, or Fisher's exact test. Statistical signi cance was set at p < 0.05.

Patients
Between May 2020 and October 2020, 300 patients were randomly divided into three groups (each n = 100) for routine exible bronchoscopy examination and treatment. We enrolled 189 men and 111 women with a mean age of 55.69 ± 12.86 years. There were no signi cant between-group differences in age, sex, and body mass index (p > 0.05, Table 1). The distribution of the disease types in the 3 groups was approximately balanced and did not affect the observation of outcomes.  (Fig. 2a). Compared with that in the CD group, the number of operations until a successful procedure was signi cantly higher in the control group (p = 0.015) (Fig. 2b). Figure 2a presents the nasal cavity-glottis time in both groups. The data are shown as mean ± standard deviation. Figure 2b presents the number of operations required for success in the two groups. Betweengroup comparisons were performed using the Mann-Whitney U test.
Postoperative complications Table 2 summarizes the occurrence of bleeding and hemostatic use after exible bronchoscopy procedures. The number of patients who presented with nasal bleedings and required hemostatic use were 13 (13%) and 5 (38.46%) patients, respectively, in the control group; 10 (10%) and 3 (3%) patients in the CD group; and 1 (1%) and 0 (0%) patients in the AD group. There was no signi cant difference between the CD group and the control group for nasal bleeding (p = 0.506); however, nasal bleeding after exible bronchoscopy was more common in the CD group than in the AD group (p = 0.005). Regarding hemostatic use, there was no signi cant difference between the CD group and the AD group (p = 0.245) ( Table 2). Tolerance and smoothness scores There were no between-group differences in the VAS scores for pain, foreign body sensation, degree of comfort toward exible bronchoscopy, and the smoothness of the operation (all p > 0.05, Table 3).

Discussion
This prospective randomized controlled study investigated whether nasal probe tests could improve the exible bronchoscopy procedure with respect to shortening the operation time and reducing postoperative complications. The results showed that probing the nasal cavity before exible bronchoscopy signi cantly reduced the time to reach the glottis and improved the rst-pass intubation success rate. Moreover, probing with cotton buds soaked in a mixture of 1‱ adrenaline and 2% lidocaine reduced nasal bleeding after exible bronchoscopy.
Regarding the e ciency of this novel method, the results showed that exible bronchoscopy with probing support reduced the manipulation time compared with the conventional approach. Probing with cotton buds allowed initial de nition of the nasal cavity anatomy. Moreover, moist cotton buds could lubricate the nasal mucous membranes, which allows easier passage of the work channel through the nasal passages. Compared with the conventional approach, nasal detection resulted in time-saving for exible bronchoscopy, which indicates that prior detection, rather than the bronchoscope itself, is more important for reducing time during the process. Moreover, the number of intubation attempts in the experimental group was lower than that in the control group, which con rmed the practical value of the timeconsuming exible bronchoscopy.
Regarding the safety of this novel method, the results showed that it had fewer additional complications than the conventional approach. Bleeding is among the most concerning complications of bronchoscopy and endotracheal intubation. 9.10 Apart from biopsy-related bleeding, bleeding caused by mechanical friction could cause anxiety and affect the quality of life of patients. 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 bleeding.
Since the introduction of the bronchoscope in 1966, it has become an increasingly important tool in the diagnosis and treatment of pulmonary diseases. 11 Moreover, bronchoscopy has emerged as a tool for improving the management of complex lung diseases. 12 Therefore, there is a need to maximize the utility of exible bronchoscopy, simplify its operating process, and reduce postoperative complications. There have been several studies on bronchoscopy, [13][14][15][16] however, there have been few studies on the examination of the nasal passages before bronchoscopy. To our knowledge, there has been no study on the in uence of nasal cavity probing. Therefore, the current study shows that the use of nasal probe tests can reduce the postoperative complications which have clinical importance given the previously described side effects associated with exible bronchoscopy. 17 Second, nasal probe tests can decrease the procedure time and the number of operations performed before successful exible bronchoscopy. They could enhance hospital single-day testing capabilities and reduce the incidence of bacteremia and post-bronchoscopy fever. 18 Geertje et al described 66 exible bronchoscopies in non-sedated adults. 16 They found that the median time to reaching the glottis with nasal and oral insertion was 52.33 s and 24.43 s, respectively, which was consistent with our ndings. This shows that the time to pass the glottis could be reduced by smooth probing or bypassing the nasal cavity. Furthermore, the nasal probes are easy to perform, low cost, and easy to spread. Moreover, they can be applied in other medical procedures, including transnasal gastroscopy and nasotracheal intubation.
Regarding this study's strengths, this is the rst prospective randomized controlled trial to assess the e ciency of probing the nasal cavity. The study sought to contribute to optimizing the nasal passage method during exible bronchoscopy. This study has several limitations. First, nasal insertion was the rst choice for the patients who underwent bronchoscopy; however, we used a 6.0-mm bronchoscope. Using a bronchoscope with a greater diameter could affect the time to pass the glottis and increase discomfort. There is a need for future studies using a 5.0-mm bronchoscope. Second, regarding bronchoscopy, the learning curve should be considered. Third, these ndings have limited generalizability since this was a single-center study. Multicenter studies should con rm the reliability of these ndings.

Conclusions
In conclusion, we recommend nasal probing as a time-saving procedure for patients undergoing exible bronchoscopy that could shorten the time to reach the glottis and reduce the number of manipulation attempts.