Article, Ultrasound

Short- vs long-axis approach to ultrasound-guided peripheral intravenous access: a prospective randomized study

Unlabelled imagelong-axis approach to ultrasou”>American Journal of Emergency Medicine (2011) 29, 1194-1197

Brief Report

Short- vs long-axis approach to ultrasound-guided peripheral intravenous access: a prospective randomized study?

Simon A. Mahler MD?, Hao Wang MD, PhD, Chadwick Lester RN, Janice Skinner RN, Thomas C. Arnold MD, Steven A. Conrad MD, PhD

Department of Emergency Medicine, Louisiana State University Health Sciences Center; Shreveport, LA 71130, USA

Received 17 May 2010; revised 22 July 2010; accepted 23 July 2010

Abstract

Objective: The objective of the study was to determine if the short-axis approach and long-axis approach to ultrasound-guided peripheral intravenous access (USGPIV) differ in success rate, catheter insertion time, and number of needle sticks.

Methods: A convenience sample of emergency department patients aged 18 to 65 years with difficult IV access (2 or more failed landmark attempts) was prospectively randomized to short-axis or long-axis USGPIV. Time from skin puncture to catheter insertion (insertion time) and number of needle sticks were recorded. Number of needle sticks and insertion time were compared using Mann-Whitney U tests. Results: Forty subjects were enrolled; 20 were randomized to the short-axis and 20 to the long-axis approach. Success rate was 95% (19/20; 95% confidence interval, 85%-100%) in the short-axis group compared with 85% (17/20; 95% confidence interval, 69%-100%) in the long-axis group. All 3 subjects with failed IV placement in the long-axis group had successful rescue USGPIV placement in short axis. Median insertion time was 34 seconds (interquartile range, 35 seconds) for the short-axis group compared with 91 seconds (interquartile range, 59 seconds) for the long-axis group (P = .02). Mean number of needle sticks was 1.5 (+-SD 0.7) in the short-axis group compared with 1.4 (+-SD 0.7) in the long-axis group (P = .82).

Conclusions: Short-axis USGPIV technique required less insertion time than the long-axis technique. Success rate was higher in the short-axis group, but this difference was not statistically significant. However, all of the failed IVs in the long axis were rescued successfully in short axis.

(C) 2011

Introduction

Peripheral Intravenous access is often required in emergency department (ED) patients. Although landmark techniques for obtaining IV access are usually successful,

? Presented at the Society of Academic Emergency Medicine Annual Meeting, Phoenix, AZ, June 2010.

* Corresponding author. Tel.: +1 318 675 6885; fax: +1 318 675 6878.

E-mail address: [email protected] (S.A. Mahler).

patients with prior IV drug abuse, obesity, and chronic medical conditions, such as Sickle cell disease or Chronic renal insufficiency, are more likely to have failed attempts [1,2]. Several studies have established that bedside ultra- sound in the ED can be used to facilitate placement of peripheral IVs in patients who have failed traditional landmark techniques [2-6]. Before ultrasound-guided peripheral intravenous access (USGPIV), patients with difficult access often underwent central venous cannulation, which has a higher complication rate than peripheral access and requires increased nursing and physician time [1,7].

0735-6757/$ – see front matter (C) 2011 doi:10.1016/j.ajem.2010.07.015

Despite ample literature supporting the use of USGPIV in patients with difficult IV access, relatively few studies have investigated placement techniques. To date, there is no accepted standard technique for USGPIV. The majority of studies have used a short-axis (transverse) approach using a standard angiocath IV catheter [2-6]. In this study, we compare USGPIV using short-axis and long-axis techniques. The objective of this study is to determine if the short-axis and long-axis USGPIV techniques differ in success rate, catheter insertion time, and number of needle sticks.

Methods

Study design and selection of participants

This is a prospective randomized study, which was approved by the Institutional Review Board of the sponsoring organization. A convenience sample of patients, aged 18 to 65 years, with difficult IV access were enrolled over a 22-month period (April 2008 to February 2010) in the ED. Difficult IV access was defined as 2 or more failed attempts at traditional landmark techniques. Patients were excluded from the study if they were younger than 18 or older than 65 years, were pregnant, or had an unstable trauma. Patients were also excluded if they required a central line rather than a peripheral IV because of hemodynamic instability, need for multiple intravenous drips, or anticipated intensive care unit admission. Written informed consent was obtained on all patients enrolled. Randomization, at a 1:1 ratio, was achieved using a computer-generated random number sequence for 40 consecutive subjects.

Study intervention

Eligible patients were randomized to a short-axis or long- axis technique for USGPIV. Ultrasound guidance was performed dynamically using a single-operator technique (in which the operator holds the probe in one hand and performs the needle stick with the other hand). A 4.45-cm 18- or 20-gauge angiocath IV catheter (Medex, Inc, Carlsbad, CA) was used for all procedures. The basilic vein was the preferred location of cannulation and was identified with a high-frequency Linear probe (5-10 MHz, L38 probe on a Sonosite Micromax, Sonosite, Inc, Bothell, WA). The needle was inserted under dynamic guidance (Figs. 1 and 2). A flash of blood confirmed entrance of the needle into the vein, and the cannula was inserted into the vein over the needle. Successful insertion was confirmed by blood return from the IV and by using power Doppler to ultrasonographically visualize flow through the catheter while it was flushed with saline.

Sonographers were allowed up to 3 attempts using the USGPIV technique from the randomization schedule. If insertion was unsuccessful in the originally randomized

image of Fig. 1

Fig. 1 Dynamic USGPIV placement using the linear array probe in the short axis.

technique, this was deemed a failed procedure. Subjects with failed procedures were crossed over to the other insertion technique for up to 3 additional attempts.

Ultrasound-guided peripheral intravenous access place- ment was performed by 1 of 4 study investigators (2 emergency medicine attending physicians and 2 ED nurses).

image of Fig. 2

Fig. 2 An ultrasound demonstrating dynamic placement of an IV catheter into a subject’s basilic vein. V indicates basilic vein.

All investigators were familiar with ultrasound-guided IV access before the start of this study from personal experience with more than 20 ultrasound-guided peripheral or Central lines and workshop attendance. The 2 emergency physicians had workshop experiences consisting of 30 minutes of lecture on ultrasound-guided vascular access and at least 1 hour of hands-on experience using Vascular phantoms. The ED nurses successfully completed a course for ultrasound- guided peripherally inserted catheters.

Data collection

The end points measured were successful or failed sonographic insertion, insertion time, number of needle sticks, and overall procedure time. All times were recorded by the investigator with a study stop watch and were self- reported. Overall procedure time started at the time the sonographer sat down at the bedside to begin identifying the basilic vein with ultrasound and stopped after the IV had been secured with tape (following power Doppler confirma- tion). Insertion time was the period from the first needle stick until blood return was noted from IV insertion. Patient satisfaction was measured using a 10-point Likert scale; and complications including hematoma, Arterial puncture, and extravasation were recorded.

Statistical analysis

An intention-to-treat analysis was performed. Insertion time, overall procedure time, number of needle sticks, and satisfaction scores were compared using Mann-Whitney U tests. The success rate and complication rate were compared using Fisher exact tests. All statistical analyses were performed with SPSS 11.0 (Chicago, IL) for Windows.

Results

Over the 22-month study period during April 2008 to February 2010, 40 patients were enrolled. A total of 20 subjects were randomized to the short-axis group and 20 to the long-axis group. Demographic characteristics of subjects are summarized in Table 1. Success rate was 95% (19/20; 95% confidence interval, 85%-100%) in the short-axis group compared with 85% (17/20; 95% confidence interval, 69%- 100%) in the long-axis group. All 3 subjects with failed IV

Table 1 Summary of patient demographics

Technique Sex Mean age +- Mean

Short axis

Long axis

P

value

Median insertion time (IQR)

34s (35s)

96s (59s)

.02

Median total procedure time

201s (331s)

236s (378s)

.68

(IQR)

Mean needle sticks +- SD

1.5 +- 0.7

1.4 +- 0.7

.82

Success rate (%)

19/20 (95)

17/20 (85)

.61

Complication rate (%)

3/20 (15)

3/20 (15)

1.00

Mean satisfaction

9.7 +- 0.7

9.5 +- 1.0

.79

score +- SD

placement in the long-axis group had successful rescue USGPIV in short axis. One of the 3 subjects with a failed procedure in long axis was switched to short axis on the basis of poor vein visualization without a needle stick in long axis. One patient randomized to short axis was unsuccessful in both techniques.

Median insertion time was 34 seconds (interquartile range [IQR], 35 seconds) for the short-axis group compared with 96 seconds (IQR, 59 seconds) for the long-axis group (P =

.0.02). In the short-axis group, the median total procedure time was 201 seconds (IQR, 331 seconds) compared with 236 (IQR, 378 seconds) seconds in the long-axis group (P =

.0.68). Mean number of needle sticks was 1.5 (+-SD 0.7) in the short-axis group compared with 1.4 (+-SD 0.7) in the long-axis group (P = .82). patient satisfaction scores and complication rates did not significantly differ between groups. Results are summarized in Table 2.

Discussion

Peripheral IV access is a common procedure performed in the ED. However, obtaining IV access in patients with prior IV drug abuse, obesity, or chronic medical conditions, such as sickle cell disease or chronic renal insufficiency, can be challenging. Studies of USGPIV on patients with difficult IV access have demonstrated a higher success rate and lower complication rate using ultrasound guidance compared with traditional techniques. Furthermore, use of USGPIV on patients with failed IV access has been shown to prevent unnecessary central venous cannulation [1-5].

Ultrasound-guided venous access is not a new concept, with literature dating back as far as 1984 [8]. However, despite ample literature supporting the use of USGPIV, relatively few studies have investigated placement techni- ques. Although the majority of prior studies have used a short-axis approach, there is currently no accepted standard technique for USGPIV [2-6]. This study compares short-axis and long-axis techniques for USGPIV. Before this study, some authorities have suggested that needle tip localization is more difficult using a short-axis technique. Difficulty in

Table 2 Comparison of end points for short- and long-axis techniques

SD (y)

weight +-

Male

Female

SD (lb)

Short axis

6/20 (30%)

14/20 (70%)

48 +- 15

201 +- 54

Long axis

9/20 (45%)

11/20 (55%)

47 +- 14

202 +- 66

needle tip localization can lead to blind past pointing. Recent studies comparing long- and short-axis techniques on internal jugular central line phantoms demonstrated a higher rate of posterior vessel wall penetration and carotid puncture in the short-axis group [9]. Advocates of the short-axis technique believe that needle localization problems can be overcome by fanning or sliding the probe. Furthermore, although needle localization may be easier in long axis, peripheral veins are often tortuous and may be difficult to align in the long axis.

In this study, patients in the short-axis group had shorter insertion times compared with those in the long-axis group (P = .02). The short-axis group also had a higher success rate (95%; 19/20) compared with the long-axis group (85%; 17/ 20). It is notable that all of the subjects with failed IV placement in the long-axis group were successfully rescued by crossing over to the short-axis technique. The only subject with failed IV placement in the short-axis group also had failed placement with the long-axis technique. There were no significant differences between the number of needle sticks, total procedure time, patient satisfaction scores, or the complication rate for the 2 groups.

Limitations

This study was performed on a convenience sample of patients with difficult IV access. By not consecutively enrolling patients, it is possible that there was selection bias. In addition, our study lacked a mechanism to ensure that all eligible patients were enrolled into the study during times when an investigator was available. All of the times in this study were self-reported. Self-reporting of data can lead to unintentional and intentional reporting bias/recall bias.

Another potential limitation of this study is the small number of sonographers. Procedures were performed on a small sample size by 4 investigators–2 ED nurses and 2 Attending emergency physicians–at a single academic ED. Therefore, results from our operators may not be genera- lizable to the average ED sonographer or other settings. The investigators, although familiar with both long- and short- axis techniques, had used predominately a short-axis approach to USGPIV before this study. Previous studies have demonstrated that operators with increased experience in ultrasound-guided vascular have higher success rates than

inexperienced operators [1,10]. It is possible that the positive results from this study are due to operator experience rather than intrinsic differences between the short- and long-axis techniques.

Conclusions

The short-axis USGPIV technique required less insertion time than the long-axis technique. Success rate was higher in the short-axis group, but this difference was not statistically significant. However, all of the failed IVs in the long axis were rescued successfully in short axis. The number of needle sticks, total procedure time, patient satisfaction scores, and the complication rate do not significantly differ between the 2 groups.

References

  1. Chinnock B, Thornton S, Hendey GW. Predictors of success in nurse- performed ultrasound-guided cannulation. J Emerg Med 2007;33(4): 401-5.
  2. Keyes LE, Bradley WF, Snoey ER, et al. Ultrasound-guided brachial and basilic vein cannulation in emergency department patients. Ann Emerg Med 1999;34(6):711-4.
  3. Constantino TG, Parikh AK, Satz WA, et al. Ultrasonography-guided peripheral intravenous access versus traditional approaches in patients with difficult intravenous access. Ann Emerg Med 2005;46(5):456-61.
  4. Constantino TG, Fojtik JP. Success rate of peripheral IV catheter insertion by emergency physicians using ultrasound guidance. Acad Emerg Med 2003;10(5):487 [abstract].
  5. Brannam L, Blaivas M, Lyon M, et al. emergency nurses‘ utilization of ultrasound guidance for placement of peripheral intravenous lines in difficult-access patients. Acad Emerg Med 2004;11(12):1361-3.
  6. Mahler SA, Wang H, Lester C, et al. Ultrasound-guided peripheral intravenous access in the emergency department using a modified Seldinger technique. J Emerg Med 2010;39(3):325-9.
  7. Steele R, Babcock C. Central line mechanical complication rate in emergency medicine patients. Acad Emerg Med 2008;8(2):204-7.
  8. Legler D, Nugent M. Doppler localization of the internal jugular vein facilitates central venous cannulation. Annesthesiology 1984;60:481-2.
  9. Blaivas M, Adhikari S. An unseen danger: frequency of posterior vessel wall penetration by needles during attempts to place internal jugular vein central catheters using ultrasound guidance. Crit Care Med 2009;37(8):2345-9.
  10. Resnick JR, Cydulka RK, Donato J, et al. Success of ultrasound- guided peripheral intravenous access with skin marking. Acad Emerg Med 2008;15:1-8.

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