A Comparative Study between Two Central Venous Access Techniques Performed by Junior Residents

The standard landmark-guided Subclavian (SC) and Internal Jugular (IJ) approaches are common bedside procedures for CVAs performed by junior residents (i.e. first-year resident) in general surgery. Despite both techniques appears similar in terms of either successful or complication rates [3,4], there are no clear evidence if any of these approaches is better to be taught initially during the early learning curve of training in surgical procedures. Therefore, this current study aimed to evaluate these two different CVAs performed by junior residents, since an estimation of the outcomes might help guide medical educators in terms of where to focus their curriculum efforts.


Materials and Methods
A comparative study was carried out in a prospective cohort of patients treated at the IMIP -Instituto de Medicina Integral Professor Fernando Figueira, a tertiary-care general hospital in Recife, Brazil.Empirically, we selected the first 100 patients that consecutively underwent the most common CVA performed at our center, the SC and the IJ approaches.Our study was also limited to adult patients (≥ 18 years) with some oncological diagnosis who underwent temporary CVA by indication according to their medical assistant team judgment.

Introduction
Central Venous Access (CVA) is a common procedure in the management of various medical conditions, providing rapid access for fluid and blood administration, hemodynamic monitoring, pacemaker insertion, and maintenance of durable access for parenteral nutrition.This procedure is often taught in residency training programs, and competency in this skill is a was absent, and venipuncture was effective in a maximum of three needle passes.Morbidity was assessed using the early mechanical complications observed in the first 24 hours after puncture such as hematoma, arterial punctures, catheter non progression or malposition, and hemothorax or pneumothorax.To study the learning curve, we divided the procedures successively performed into quartile periods, which is similar to a method we had previously applied in previous studies [8,9].Descriptive statistics, rates of successful and morbidity were summarized as medians (interquartile range) or frequencies (percentages) and analyzed using conventional statistical methods, considering a two-tailed p-value of 0.05 as statistically significant.This study was approved by our ethics research committee (protocol number 2875) and partially presented as a poster (PO 1268) during XXX Brazilian Congress of Surgery.

Results
One hundred-three consecutive patients undergoing CVA performed by our four junior residents from February 2011 to February 2012 were initially selected for analysis.However, three of them were excluded because of inappropriate records (n = 1) and puncture after the sample size required was accomplished (n = 2).Among the patients analyzed, 35% had previous history of central venous assessment in the past, whereas the most part of CVA procedures in this current study were performed by the right side (88%).Fifty-six patients (56%) underwent venipunctures using the IJ approach and 44 (44%) using the SC technique.Their baseline characteristics and descriptive  Hepatobiliopancreatic=5; head and neck=4; thorax=3; urology=2; others=3.

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Including one case for invasive monitoring and one case because of catheter-related infection (exchange of the catheter).
statistics according to patient's variables and procedure-related variables are summarized in Table 1.

Discussion
The Brazilian National Ministry of Education officially implemented the medical residency programs as postgraduate specialization courses for medical doctors in the 1970s, but they were previously used as a training model since the 1940s [10,11].Currently, these programs are the main method to train specialist physicians in our country after a regular medical course lasting six years.In the general surgery field, a core curriculum guided by medical and surgical competencies has been normalized by our National Committee of Medical Residency (CNRM) since 2006 [12].In these settings, our medical residency program has offered four new openings a year for the surgical training program in general surgery, which has been mostly preferred by medical doctors interested in this medical field at our state (Pernambuco).
The ability to perform CVA competently is an important part of the initial surgical training [13], and both standard techniques of SC (infraclavicular approach) and IJ (anterior approach) access procedures have been mainly and equally taught at our department in order to provide our residents with comprehensive surgical skills in performing CVA.From an anatomical point of view, right-sided procedures have been preferred [14], and other alternative techniques of CVA by puncture or surgical cut-down access has also been taught.Thus, exploring some evidence to select the best approach to teach initially during the early learning curve of the surgical training, we examined a cohort of patients who consecutively underwent CVA performed by junior residents from our department.Herein, the overall rates of successful CVA and morbidity did not significantly differ between the techniques and were found to be similar to those from other recent studies [3,4,[15][16][17][18], but interestingly, we found no significant impact by the resident learning curve on these outcomes.Because of an absolute statistically nonsignificant difference of 20% between rates from the first to the last quartile periods, we supposed these findings mainly resulted from our limited sample size, since this difference is probably important from a clinical point of view.Similarly, we also observed there are more arterial punctures but less catheter malpositions with the internal jugular compared with the subclavian access, as previous reported by Ruesch S et al. [3] in a systematic review including data on 2,085 jugular and 2,428 subclavian catheterizations from 17 prospective comparative trials.
Many studies have confirmed that both landmark-guided CVA techniques are feasible and safe with similar complication rates [3,4,15], but the ultrasound-guided techniques have showed lower proportion of failures and complications rates [19,20].Ultrasound-guided CVA is a helpful technique to gain CVAs [21] and the learning process of ultrasound-guided CVAs appears safe and feasible for training medical residents [16].Although the ultrasound-guided techniques already has been incorporated into our currently developing medical residency program in general surgery, unfortunately, ultrasound devices had not been easily available for our residents at the time of this study.
Despite a relatively small sample size, the main scientific merit of this study was to explore this issue in the context of surgical training, whereas an estimation of success and morbidity rates might help guide our medical educators in terms of teaching bedside procedures and also be used as baseline for planning future clinical trials.Furthermore, our database had been prospectively collected and continuously updated to our own feedback, while the residents were instructed to perform both techniques alternately unless a specific contraindication was present.These approaches played a role as a simplified method of randomization in this analysis.Finally, to add some homogeneity to our sample, we limited this study to adult patients with a cancer diagnosis, because it was previously observed that most CVAs have been performed in this setting at our department.

Conclusions
We only observed a different profile of complication rates with no others differences between the IJ and SC approaches in

Table 1 :
Baseline characteristics and descriptive statistics according to patients-and procedures-related variables.
2Mann-Whitney U-test or chi-square tests, including Yates's correction and Fischer's exact test as appropriated.3Includingone case with 4 needle passes and other with 5 needle passes.

Table 2 :
Frequency of puncture complications after the central venous access procedures.Appling the Fischer's exact test and considering only the total complicated cases.
1 2Hematoma in 2 cases.One of them after an arterial puncture and other case without arterial puncture (venous hematoma).