THE CRITICAL VIEW OF SAFETY PREVENTS THE APPEARANCE OF BILIARY INJURIES? ANALYSIS OF A SURVEY

ABSTRACT
 
Background:
 The risk of bile duct injury (BDI) during cholecystectomy remains a concern, despite efforts proposed for increasing safety. The Critical View of Safety (CVS) has been adopted promoting to reduce its risk. 
Aim:
 To perform a survey to assess the awareness of the CVS, estimating the proportion of surgeons that correctly identified its elements and its relationship with BDI. 
Methods:
 An anonymous online survey was sent to 2096 surgeons inquiring on their common practices during cholecystectomy and their knowledge of the CVS. 
Results:
 A total of 446 surgeons responded the survey (21%). The percentage of surgeons that correctly identified the elements of CVS was 21.8% and 24.8% among surgeons claiming to know the CVS. The percentage of surgeons that reported BDI was higher among those that incorrectly identified the elements of the CVS (p=0.03). In the multivariate analysis, career length was the most significant factor related to BDI (p=0.002). 
Conclusions:
 The percentage of surgeons that correctly identified the Critical View of Safety was low, even among those who claimed to know the CVS. The percentage of surgeons that reported BDI was higher among those that incorrectly identified the elements of the CVS.

Assessing safe LC is an arduous task; however, it remains a priority for many organizations. Examples of these efforts include the launch of the Safe Cholecystectomy Task Force by the Society of American Gastrointestinal Endoscopic Surgeons in 2014 19 and the Dutch Health Care Inspectorate making CVS mandatory in the Netherlands in 2009 5 .
As an effort to participate in the global endeavor for increasing LC safety, we performed a survey of surgeons in Latin America. Our main objectives included assessing How to cite this article: Giménez ME, Houghton EJ, Zeledón ME, Palermo M, Acquafresca P, Finger C, Serra E. Visão crítica de segurança previne lesões biliares? Análise de um levantamento. ABCD Arq Bras Cir Dig. 2018;31(2):e1380. DOI: /10.1590/0102-672020180001e1380 Original Article 1/5 the awareness of CVS, estimating the proportion of surgeons that correctly identified its elements, and its relationship with BDI. Also, were analyzed the relationship among other factors such as career length, intraoperative cholangiography (IOC) and workplace.

METHODS
This is a prospective, observational, comparative and transverse study. It was conducted after approval from the Investigation Ethics Committee of the Bernardino Rivadavia Hospital (No.DC-2017-296-HBR).
In June of 2017, a total of 2340 email addresses of surgeons were selected from the database of the DAICIM Foundation (Buenos Aires, Argentina) as recipients for an anonymous online survey. A form was sent by email (using Google Forms by Google). The survey was closed once the estimated sample size was obtained. Surgeons working in Latin America were included and forms that were incompletely filled, excluded. The main outcome was the percentage of surgeons that reported BDI, comparing with the independent variable "correctly identified elements of CVS", with control of the variable "career length".

Statistical analysis
All statistical analyses were performed using SPSS 11.5 y VCCstat 2 . When necessary the standard deviations and confidence intervals of 95% (CI95) were estimated, and the following statistical significance tests were applied: Students T-test, ANOVA, Chi-squared, and Fishers test. A p-value of <0.05 was considered as significant statistically. For the multivariate analysis, a binary logistic regression was performed with an alfa entry level=0.05 and an exit alfa of =0.10.

RESULTS
A total of 446/2096 (Table 1, Figure 2) surgeons answered the questions (response rate of 21.2%); 244 contacts were badly addressed and one survey was discarded due to incomplete information; therefore, 445 surveys were qualified.
Questions and answers done to the surgeons are in Figure 1.
Of the 92 surgeons that correctly identified the elements of the CVS, 33 reported BDI (35.9%) (CI95 26.1-46.5), and among the 348 that incorrectly identified them, 163 reported BDI (48.5%)(CI95 42.5-54.6) (Chi Yates p=0,0457). Five surgeons admitted that they did not know the CVS; however, they correctly identified its elements (all five did not report BDI); as their correct answers were random, they were excluded from the previous analysis.
In regard to analyzing a possible relation in the average career length with the correct identification of the elements of the CVS, the results showed that the average career length of respondents was 16.86 years (CI95 14.97-17). However, among surgeons that correctly identified the elements of the CVS, the average was 12.58 (CI95 10.18-13.81), whereas it was 18.06 (CI95 16.73-19.26) among those that incorrectly identified the elements of the CVS (T test p=0.0005).

Question 1) How many years have you been a surgeon?
Answer: The average career time (ACL) among the revolutionaries was 16.86 years (IC95 14,97-17).

Question 2) In which province and / or country do you work?
Answer: Table 1 and Figure 2 Question 3) Where do you work? Options -respondents can choose more than one option: A) Public Hospital (PH) with residence program (PR); B) Public Hospital without RP; C) Private institution with PR; D) Private institution without PR; E) Private practice Answer: Table 1 p=0.00028). Therefore, as both longer "career length" and incorrect "identification of the elements of CVS" were statistically associated with "reported BDI", a logistic regression multivariate analysis was necessary to determine which one was more relevant.
This analysis was performed using as independent variables: "identification of the elements of CVS" and "career length", to predict the appearance of the event "BDI". As a result, "career length" was the most significant factor related to a higher percentage of surgeons reporting BDI (p=0.0002). The threshold was found between 15 and 19 years, and above a set value of 16 years, the risk of reporting BDI is 1.7 times increased (OR 1.7 CI95 1.14-2.44, Table 3)  Because of the absence of a statistical difference in the previous analysis, the career length between nonteaching centers and SRP centers was also analyzed. In non-teaching centers, the average career length was 20.22 (SD: 12.08) and in SRP centers, the average was 15 When analyzing if the percentage of surgeons that routinely and incidentally perform IOC was higher in SRP centers, the results ( Table 5), showed that there was a statistically significant difference favoring those working with residents when compared to those in non-teaching centers (Chi Yates p=0.003).

DISCUSSION
Bile duct injury during LC is a distressing event that can significantly alter a patient's life. Strasberg's CVS has emerged as a useful tool for improving safety 5,6,27 . However, some reports highlighted that despite of its use, the incidence of BDI has not necessarily decreased 15,20,21,22,23 . Several studies have suggested education of CVS, strict video or photographic documentation of it during surgeries, and even confronting surgeons with their low results, as methods to increase the impact of CVS use 4,15,20 .
A similar large-scale, multinational survey, by Hibi et al. 13 , found that surgeons' perceptions during LC are workplace-dependent, and some common indices are collectively inapplicable in multicenter, international trials; this overlaps with safety measures such as the use of CVS. In the same way, an evaluation of LC protocols of Dutch hospitals in 2008 by Wauben L. et al. 28 found that even in this setting, protocols differed widely and the sections relating to the CVS, presented omissions such as: many protocols not mentioning the terms 'Calot´s triangle dissection' or not describing its complete dissection. These studies suggest that awareness and the correct application of the CVS may be dissimilar.
The present survey found that a surprising 78% of respondents did not recognize correctly the elements of the CVS. But more concerning, was the finding that out of the group of surgeons that claimed to know the CVS, 75% were mistaken. Because most studies on the subject of CVS and its use, have not clearly stated that the surgeons performing the LC were certified as to knowing the elements of the CVS 6,15,16,25,26 -even though the premise of surgeons confirming the obtainment of CVS presupposes their knowledge on the subject -our findings suggest that confirmation of the fact, may be necessary and that this observation could be an explanation as to why CVS has not had the impact it should have.
Our results also found that surgeons with a shorter surgical career were more aware of the CVS; this could support that the recent contact with a training program might be associated with awareness of the CVS. Similarly, the results showed a significant association of surgeons working in SRP centers with knowledge of the CVS and a shorter surgical career. These, results support the notion that CVS is a relatively "young" technique that is commonly found among young surgeons in academic settings. This tHe criticAl VieW OF SAFetY PreVentS tHe APPeArAnce OF BiliArY inJUrieS? AnAlYSiS OF A SUrVeY 3/5 situation proposes prioritizing the dissemination of CVS among older surgeons and those working in non-teaching centers.
Other findings of this study included that a greater knowledge of the CVS and a shorter surgical career were both associated with surgeons that did not report BDI. However, in a multivariate analysis, career length was the more significant factor related with the appearance of BDI (p=0.0002), including the risk of BDI increasing almost two-fold (OR 1.7 CI95 1.14-2.44) after 16 years. This result suggests that, at present, a longer surgical career is more of a risk factor for the appearance of BDI, than ignorance of the CVS.
With these associations, it would follow that surgeons working in SRP centers (younger surgeons, more aware of the CVS) would logically have lower BDI reports; however, this was not the case. In a comparison of the reports of BDI between, centers with SRP and non-teaching centers, the response rate for BDI was not statistically significant (p=0.57 Chi-Yates test). Several possible explanations could be responsible for this 'equalization' between BDI rates among SRP vs. non-teaching centers. LC with higher degrees of difficulty in SRP centers, with a corresponding selection of "easier" cases in non-teaching centers, would likely be the most obvious factor that could simultaneously increase BDI in the former while decreasing it in the latter. Furthermore, more experience in "older" surgeons in non-teaching centers, and incorrect CVS application by "younger" surgeons in SRP centers, could also play a part in this finding.
Our study has some limitations. Twenty percent of response rate could be pointed out very low; however, according to Sheehan 22 the response rates to email surveys have been decreasing over time and by the beginning of the millennium, they oscillated by 20%. Our response rates was within that range 21 . In the survey, we did not ask the surgeons the exact number of BDI that they had incurred in their careers. Therefore, our analysis could not differentiate between surgeon's experience and the accumulative effect of time in relation to BDI. Secondly, we described that the percentage of surgeons reporting BDI was lower in the group that correctly identified the elements of CVS. However, correctly identifying them is not the same as using correctly and routinely in practice, and assuming that, could be a potential bias of our study.
Finally, our conclusions include that the percentage of surgeons that correctly identified the elements of CVS was much lower than expected (21.8%) even among those who claimed to know the CVS. Therefore, this aspect should be noted in future investigations and in educational programs. Also, the percentage of surgeons that reported BDI was higher among those that incorrectly identified the elements of the CVS; however .a longer career length was the most significant factor related to BDI.

CONCLUSIONS
The percentage of surgeons that correctly identified the Critical View of Safety was low, even among those who claimed to know the CVS. The percentage of surgeons that reported BDI was higher among those that incorrectly identified the elements of the CVS.