Should We Pay More Attention to Endotracheal Tube Fixation during Anesthesia—Surveys from Chinese Anesthesiologists for Endotracheal Tube Fixation and Endotracheal Tube Displacement in 2014 and 2020

Background: Displacement of endotracheal tube (ETT) can result in endobronchial intubation and accidental extubation that severely threatens safety of surgical patients. However, few surveys have investigated intraoperative ETT displacement experienced by anesthesiologists. The objective of these surveys was to investigate ETT fixation method and ETT displacement during general anesthesia experienced by anesthesiologists in China in 2014 and 2020. Methods: A questionnaire was designed with twenty questions and randomly distributed to anesthesiologists in two survey methods. In 2014, we collected responses from anesthesiologists who participated in the 22nd annual meeting of the Chinese Society of Anesthesiology in a face-to-face set-ting; in 2020, anesthesiologists from twenty-eight provinces completed the questionnaire through an online questionnaire survey platform. Differences in the responses from the anesthesiologists in 2014 and 2020 were assessed with a chi-square test. Results: In total, 568 questionnaires were collected, of which 541 questionnaires were valid (valid response rate 95.2%). A majority of the respondents (65.6%) had experienced ETT displacement, and 4.3% of respondents had experienced serious complications due to ETT displacement. Three hundred and twenty-nine respondents (60.8%) fixed the ETT with adhesive tape in the shape of the letter X. ETT displacement that can result in serious consequences. Therefore, the management of ETT should be a priority during the operation.


Introduction
Securing the endotracheal tube (ETT) following intubation is a routine procedure during general anesthesia with tracheal intubation. Proper fixation of the ETT is crucial for effective ventilation during general anesthesia while minimizing potential complications due to ETT displacement. Displacement of the ETT can result in endobronchial intubation and accidental extubation [1]. If unrecognized, endobronchial intubation can lead to hypoxemia caused by atelectasis formation in the unventilated lung, and hyperinflation and barotrauma with the development of pneumothorax of the intubated lung [2]. Accidental extubation can lead to serious complications, such as laryngeal injury, vocal cord injury, aspiration, respiratory arrest, arrhythmias, hypoxemia, hypotension, cardiac arrest, anoxic brain injury, or even death [3]- [8].
Although many methods of securing ETT, including adhesive tapes, sutures, silk ties, commercial ETT holders, umbilical cord clamps, or a combination of these techniques have been used to reduce the displacement of ETT, the best method of securing ETT remains a controversial issue [9]- [14]. Additionally, anesthesia textbooks do not describe how to fix ETT in detail. The case reports of accidental extubation during general anesthesia can still be found in recent years [7] [15] [16] [17] [18] [19], however, the cases of ETT displacement and its consequences might be underestimated in the literature. Therefore, the objective of the surveys was to investigate how many anesthesiologists had ever experienced the ETT displacement and its consequences during anesthesia, and the surveys were performed in 2014 and 2020 respectively, in China. The results for 2014 with those for 2020 were compared to investigate the advance in ETT fixation methods. This survey will provide preliminary information on ETT fixation methods, ETT displacement frequency and the possible factors to cause ETT displacement.

Questionnaire Design
The relevant literature was searched through the PubMed medical literature retrieval system with keywords, such as "accidental extubation", "endotracheal tube", "displacement", "fixation", and "questionnaire survey". According to the results of the literature search and the experience of ETT securement in the clinic, we designed the questionnaire.  The questionnaire consisted of twenty questions, which involved the characteristics of respondents, the ETT fixation methods, the ETT displacement and its   consequences experienced by the anesthesiologists, and the factors influencing   the anesthesiologists to determine the method of fixing the ETT (for details, see supplementary materials).

Respondents and Investigated Methods
One hundred and eighty questionnaires were randomly distributed to anesthesiologists who participated in the 22nd annual meeting of Chinese Society of Anesthesiology in Chengdu, China on September 12th and 13th, 2014. The questionnaires were promptly returned after being answered. In 2020, the questionnaires were distributed and collected through the "questionnaire star" online questionnaire survey platform via WeChat, and 378 anesthesiologists from twenty-eight provinces in China volunteered to complete the questionnaires from August 28th to 30th. All of the respondents should have more than one year of clinical anesthesia working experience. Interns and anesthesiologists assistants were excluded from this survey. Before completing and submitting the survey, the anesthesiologists were informed about their consent to participate in the survey and authorized the researchers to analyze their responses. The anesthesiologists were informed that no identifiable information would be published or released.

Data Collection
The questionnaires were collected and stored in department of anesthesia, the Sixth Affiliated Hospital, Sun Yat-sen University. The valid questionnaires were selected if they met the following requirements. First, the written responses to all of the questions were legible; second, there were no mistakes among the answers; third, there were no inherent contradictions among the answers.

Statistical Analysis
The categorical variables were presented as number and percent. Continuous variables were presented as mean ± standard deviation (SD). Comparison of working experience between respondents in 2014 and 2020 was assessed with the Kruskal-Wallis test. Comparison of mean cases of ETT displacement experienced by respondents between 2014 and 2020 was assessed with the Mann-Whitney U test. Chi-square test with correction for continuity was used to compare the influence of surgical site and position on ETT fixation between 2014 and 2020. Comparison of other categorical variables was assessed with the chi-square test. Logistic regression was used to analyze the relationship between ETT displacement and professional titles, fixing ETT by themselves or not, fixation materials, fixation methods, whether to place bite block, fixation methods after bite block, whether to consider the surgical site and position, and whether to consider the age. The forward method was used as the screening method of the independent variable. Statistical analysis was performed by SPSS 16.0 (SPSS Inc., USA). For Open Journal of Anesthesiology all analyses, the two-tailed P value of less than 0.05 was considered statistically significant.

Characteristics of the Respondents
A total of 568 questionnaires were collected, of which 541 were valid (valid response rate 95.2%). The respondents were from 28 provinces in China. The province distribution of the respondent's hospital is shown in Figure 1.
The constituent ratios of hospital category, hospital grade, professional title, work experience, and cases of endotracheal intubation performed per month are shown in Table 1. Approximately 60% of respondents had the professional title  of attending physician or higher. The constituent ratios of the respondents' professional titles between 2014 and 2020 had significant differences (P = 0.01), fewer chief physicians took part in 2020's survey. More than 60% of respondents had more than 5 years of work experience and 83% of respondents performed more than 25 cases of endotracheal intubations per month.

ETT Fixation Methods in Clinical Anesthesia
As shown in Table 2, 77.8% of the respondents indicated that they could fix ETT by themselves after intubation. In comparison to respondents in 2014, proportionately higher numbers of respondents fixed ETT by themselves in 2020 (67.7% vs. 82.9%, P < 0.001). Among the respondents, 90.4% indicated they routinely secured the ETT with adhesive tape, including silk medical adhesive tape (49.5%) and plastic medical adhesive tape (40.9%). A total of 60.8% of respondents stated that they fixed ETT in the shape of the letter X, using two pieces of adhesive tapes of appropriate length and width, where one piece of tape was attached to one side of the cheek, wrapped around the tube two circles, and subsequently cross-fixed on the same side of the cheek, and the other piece of tape was attached to the other side of the cheek, wrapped around the tube two circles, and then cross-fixed on the same side. In comparison to respondents in 2020, proportionately higher numbers of respondents in 2014 fixed ETT in the shape of the letter X (P < 0.001) ( Table 2).
And 87.6% of the respondents stated that they usually placed a bite block after endotracheal intubation, proportionately fewer respondents place a bite block in 2020. When placing a bite block, proportionately fewer respondents first secured the ETT and then fixed the bite block with the ETT in 2014 compared to 2020 (44.1% vs. 52.8%, P = 0.004) ( Table 2).

ETT Displacement and Consequences
Among the respondents, 65.6% (355/541) had experienced ETT displacement. Open Journal of Anesthesiology Data are expressed as the number of the respondents (percentage). The shape of letter X: Using two pieces of adhesive tapes of appropriate length and width, where one piece of tape was attached to one side of the cheek, wrapped around the tube two circles, and subsequently cross-fixed on the same side of the cheek, and the other piece of tape was attached to the other side of the cheek, wrapped around the tube two circles, and then cross-fixed on the same side.

The Factors Influencing the Anesthesiologists to Determine the Method of ETT Fixation
Among the respondents, 97.8% stated that they considered the influence of surgical site and position on ETT fixation, and 77.1% took the age of patients into account when securing the ETT. Proportionately higher numbers of respondents considered the influence of age on ETT fixation in 2014 compared with respondents in 2020 (P < 0.001) ( Table 3). The fixation materials used in head and neck surgery, prone surgery and pediatric surgery are shown in Table 3.
As for patients in the supine position underwent except head and neck surgery, Open Journal of Anesthesiology the primary cause of ETT displacement is shown in Figure 4. The constituent ratios of the primary cause of ETT displacement between 2014 and 2020 were significantly different (P < 0.05) (Figure 4).

Discussion
The surveys indicate that a majority of anesthesiologists in China experienced ETT displacement during general anesthesia in 2014 and 2020. A minority of anesthesiologists even experienced cardiac arrest and death of patients due to a supine-to-prone position change were more likely to experience ETT displacement [24]. Additionally, children younger than 2 years presented greater unplanned extubation rates than children over 2 years [25]. Another study found that unplanned extubations were more common in children who were younger than 5 years compared with older children [26]. In our survey, lower profession title, without placing the bite block, without the consideration of surgical site or position and without the consideration of age were the risk factors of ETT displacement. So a majority of respondents had considered the influence of surgical site, position, and age on securing ETT. As such, a majority of respondents indicated that they reinforced the ETT with adhesive tape, transparent film dressing, or other materials.
Previous studies on the optimum fixation material and method have yielded contradictory results [9] [12] [13] [27]. Our survey found that there were differences in fixation methods between 2014 and 2020, the fixation materials did not change significantly. Adhesive tape was the most commonly used fixation material in clinical practice and only a minority of respondents routinely used other materials, including transparent film dressing, bandages, sutures, ETT-holders.
The proportion of respondents who stated that improperly fixing ETT was the primary cause of ETT displacement was higher than that who indicated that poor quality of fixation materials led to ETT displacement (37.3% and 2.8%, respectively). In the opinion of respondents, the fixation methods were more critical than the fixation materials for preventing ETT displacement. Our survey showed a majority of respondents secured ETT with adhesive tape in the shape of the letter X. In addition, the fixation method in the shape of letter H, the fixa- The major limitation of this study was that the cases and the consequences of ETT displacement were reported solely by the memory of the respondent, and there might be some discrepancy between the respondents' memory and the clinic records. Additionally, except for work experience and professional titles, other factors such as gender or educational background, might also affect the fixation of ETT, which we hope to address in our future work. Moreover, the differences in the survey methods may have led to differences in the characteristics of respondents. Compared with the online survey, a higher proportion of face-to-face respondents came from grade 3 class A hospitals and were chief physicians, which may have led to differences in the incidence of ETT displacement experienced by respondents between 2014 and 2020.

Conclusion
In conclusion, a majority of anesthesiologists experienced ETT displacement, which may result in serious complications during general anesthesia. Therefore, management of the ETT should be paid more attention during the operation. Open Journal of Anesthesiology

Supplementary Materials
Questionnaire of ETT displacement Do you agree to participate? Yes No Your basic information 1) Your hospital Province: City The method for fixing the ETT with adhesive tape: a) Fixed the ETT in the shape of the letter X* b) Fixed the ETT in other methods *The shape of the letter X: using two pieces of adhesive tapes of appropriate length and width, where one piece of tape was attached to one side of the cheek, wrapped around the tube two circles, and subsequently cross-fixed on the same side of the cheek, and the other piece of tape was attached to the other side of the cheek, wrapped around the tube two circles, and then cross-fixed on the same side. 11) When placing a bite block, the method that you fixed the ETT was: