Practice of ultrasound-guided central venous catheter technique by the French intensivists: a survey from the BoReal study group

All guidelines recommend the use of US for CVC placement because US has been shown to increase successful catheter placement and to reduce complications [1–5]. General barriers to ultrasound-guided CVC include access to equipment and proper training. In our region we have implemented special courses to promote the use of US with formal training and simulators which should be associated with a high rate of US procedures. Our results are encouraging as 68 % of our physicians use “always” or “almost always” the US. In 2007, Bailey et al. [6] reported only 15 % of cardiovascular anesthesiologists in the USA who performed always or almost always US technique. Moreover, the 18 % of our physicians declaring systematically using US is higher than the 5 % reported by Mimoz et al. [14] in a population of French intensivists in 2006. The proportion of physicians who never used US was lower (6 %) in our study compared to previous studies (44 % in the study by Buchanan et al. [12]). Therefore, our results are better than those of previous surveys. We compared residents and senior physicians to identify current trends in the use of US. This comparison confirmed a trend toward increased use of US among younger physicians who also reported less frequently a lack of training to justify the use of landmark technique (Table 3).

The first reason reported by the physicians in our survey for not using US was “they don’t need ultrasound” (36 %) (Table 1). The same reason of “no apparent need” has already been reported in previous surveys [6, 7]. Despite more than 5 national and international guidelines recommending the use of US, some physicians still consider landmark procedures as a reasonable alternative. More than 40 studies and 7 meta-analyses have shown a clear benefit of using US in terms of success rate and complications. No study has ever demonstrated the superiority of landmark technique over the US-guided technique. However, a proportion of physicians may still consider the benefit of using US to be very minor. It is noteworthy that our survey showed that the subclavian site was the site associated with the lowest rate of US guidance (9 %) compared with the jugular (45 %) and femoral (19 %) sites (Table 1). Although, historically, the jugular vein has been most extensively studied, several studies have now also demonstrated the benefits of US for femoral and subclavian CVC placement, which is why US is now recommended in all sites. For example, in a study based on more than 400 subclavian procedures, Fragou et al. [15] demonstrated the superiority of the US-guided technique over the landmark technique in terms of success rate, number of punctures, complications and procedure time. The recent meta-analysis published by the Cochrane database showed a benefit of US for the jugular site in terms of success rate, complication rate and procedure time [16]. For the subclavian vein, US provides a benefit in terms of arterial puncture and hematoma, but not in terms of success rate and only a benefit in terms of success rate is observed for the femoral site [17]. As stated by the authors of the review, fewer studies have been conducted on the subclavian and femoral veins compared to the jugular vein and the studies included in this meta-analysis were very heterogeneous. More than 5 additional studies on subclavian or femoral vein CVC placement, published since this meta-analysis, have confirmed the superiority of US. Interestingly, our survey shows that residents use more frequently the US for subclavian site than the seniors (Table 3). It is highly possible that in the next years the rate of US subclavian CVC will increase.

In previous surveys, lack of training and absence of an ultrasound machine were cited as the main reasons for not using US [7]. In our region, only 11 % of physicians reported the absence of US training and 3 % reported absence of an ultrasound machine to explain the use of the landmark procedure, which could explain the more frequent use of US procedures in our region compared to previous surveys. However, availability of an ultrasound machine was still a limiting factor for residents, who more frequently reported inaccessibility of the ultrasound machine than seniors to explain use of the landmark technique (Table 3).

Ninety-one percent of physicians recommended teaching the landmark technique, indicating that a large proportion of the physicians who always use US guidance believe that physicians should still be able to perform CVC placement without US. What can justify to perform a landmark procedure if you have an US machine in your setting and you have been trained to US procedures? The only situation remaining is an extreme urgent situation. Fifty-three percent of physicians reported having experienced an emergency situation in which they were unable to wait for the ultrasound machine at least once during the last year. Such situations could justify teaching the landmark technique as a rescue technique, especially as we have demonstrated that residents who have only learned the US-guided technique are unable to perform a landmark procedure [18]. But teaching the landmark procedure during emergency situations where you do not have the time to wait for the US (cardiac arrest for example) is not recommended. The residents will have to perform and learn landmark procedures in nonemergency patients which is associated with a high rate of complications and low success rate during their learning curve. The use of intraosseous catheter could be a good alternative to CVC in case of extreme emergency as previously reported [19, 20].

Our survey presents several limits. The survey responses were self-reported; thus, unknown errors or bias may have resulted from this type of study. In an attempt to keep survey questions brief, questions may have been ambiguous and may have been misinterpreted from their original intent. However, the pilot testing and the test–retest performed by 5 physicians were used to improve the questionnaire as recommended [13]. Our response rate of 66 % may be considered insufficient increasing the risk that our results differ from the nonrespondents. But a response rate between 50 and 60 % is usually considered as acceptable, and the mean response rate reported for physicians in published surveys is between 54 and 61 % [13, 21].

In conclusion, training in ultrasound techniques and the widespread availability of ultrasound machines in ICUs seem to improve the rate of US procedures. However, a proportion of physicians still continue to perform landmark techniques and consider this technique as an alternative to US. The translation of evidence to clinical practice regarding the benefits of ultrasound guidance for central venous catheter placement faces many barriers. The belief that they do not need US despite strong scientific evidence and the desire to continue to teach the landmark technique to residents indicate the aspiration of physicians to continue landmark procedures. Training and education are potentially still the best ways to overcome such barriers or conviction.