title: Effects of long axis in-plane vs short axis out-of-plane techniques during ultrasound-guided vascular access.
abstract: BACKGROUND
  Currently, whether long-axis in-plane (LA-IP) is superior to short-axis out-of-plane (SA-OOP) during ultrasound-guided vascular access remains inconclusive. We, therefore, conducted a meta-analysis of randomized controlled trials to compare the effects of LA-IP vs SA-OOP techniques in patients undergoing ultrasound-guided vascular access (USGVA).
  
  
  METHODS
  A computer-based literature search of PubMed, Embase, and the Cochrane Library (up to October 2015) was performed to identify randomized controlled trials that evaluated the effects of LA-IP compared with SA-OOP in patients undergoing USGVA. The primary end point was the first-pass success rate. Secondary end points included mean time to success, mean attempts to success, and incidence of the complication of hematoma. Weighted mean differences (WMDs) and relative risks (RRs) with 95% confidence intervals (CIs) were calculated by random-effects model.
  
  
  RESULTS
  Five eligible studies with a total of 470 patients satisfied the inclusion criteria. There was no significant difference for the first-pass success rate (RR, 1.06; 95% CI, 0.91-1.23; P = .44), mean time to success (WMD, 4.78seconds; 95% CI, -4.43 to 13.99; P = .31), mean attempts to success (WMD, 0.06 times; 95% CI, -0.23 to 0.35; P = .69), and incidence of the complication of hematoma (RR, 2.86; 95% CI, 0.32-25.42; P = .35) between the LA-IP and SA-OOP groups.
  
  
  CONCLUSIONS
  There is insufficient evidence to definitively choose either LA-IP or SA-OOP in patients undergoing USGVA. Further robustly well-designed trials are warranted to investigate the appropriate technique in patients receiving USGVA.
authors.affiliation: Department of Ultrasonography, Qilu Hospital, Shandong University, Jinan, 250000, Shandong, China; Department of Ultrasonography, Affiliated Hospital of Binzhou Medical University, Binzhou, 256603, China.
authors.forename: Yan-Bing
authors.initials: YB
authors.lastname: Gao
authors.affiliation: Department of Ultrasonography, Affiliated Hospital of Binzhou Medical University, Binzhou, 256603, China.
authors.forename: Jun-Hong
authors.initials: JH
authors.lastname: Yan
authors.affiliation: Department of Spine Surgery, Binzhou People's Hospital, Binzhou, 256610, China.
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Ma
authors.affiliation: Department of Ultrasonography, Affiliated Hospital of Binzhou Medical University, Binzhou, 256603, China.
authors.forename: Xiao-Na
authors.initials: XN
authors.lastname: Liu
authors.affiliation: Department of Ultrasonography, Affiliated Hospital of Binzhou Medical University, Binzhou, 256603, China.
authors.forename: Jing-Yun
authors.initials: JY
authors.lastname: Dong
authors.affiliation: Department of Ultrasonography, Affiliated Hospital of Binzhou Medical University, Binzhou, 256603, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Sun
authors.affiliation: Department of Ultrasonography, Affiliated Hospital of Binzhou Medical University, Binzhou, 256603, China.
authors.forename: Li-Wei
authors.initials: LW
authors.lastname: Tang
authors.affiliation: Department of Ultrasonography, Qilu Hospital, Shandong University, Jinan, 250000, Shandong, China. Electronic address: sddxql2015@163.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
mesh_terms: D002405:Catheterization, Central Venous / Q000379:methods*; D002406:Catheterization, Peripheral / Q000379:methods*; D006801:Humans; D015233:Models, Statistical; D017063:Outcome Assessment, Health Care; D016032:Randomized Controlled Trials as Topic; D018084:Ultrasonography, Interventional / Q000379:methods*