***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Objective To examine the feasibility of a routine transradial approach ( TRA ) in primary percutaneous coronary intervention ( PPCI ) for acute ST-segment elevation myocardial infa rct ion ( STEMI ) . Design A single-centre observational study with prospect i ve data collection . Setting A high-volume interventional centre in Amsterdam , The Netherl and s. Patients Procedural data were analysed for 2209 consecutive patients presenting with STEMI without cardiogenic shock , between January 2001 and December 2008 . Interventions PPCI routinely performed by the TRA . Main Outcome Measures The primary outcomes of interest were the need for crossover to another vascular access site , the achievement of procedural success and their trends over time . Secondary outcome measures were trends in total procedural duration , fluoroscopy times and use of equipment . Results In a total of 2209 procedures the radial artery was the primary access site , comprising 96.1 % of all procedures performed during the study period . In 84 cases ( 3.8 % ) access site crossover was needed . Crossover rates decreased from 5.9 % in 2001–2 to 1.5 % in 2007–8 ( p=0.001 ) . The procedural success rate was 94.1 % , which remained stable over the years . Despite an increased complexity of PPCI ( more non-left anterior descending infa rct -related arteries , thrombus aspiration and multivessel PPCI ) , total procedural duration decreased from 38 min ( IQR 28–50 ) in 2001–2 to 24 min ( 18–33 ) in 2007–8 , p<0.001 for trend . Conclusions Systematic use of the TRA in PPCI yields low access site crossover , high procedural success rates and excellent procedural performances . It can therefore represent the primary access site in the vast majority of STEMI patients BACKGROUND : Radial arterial cannulation is most commonly done using palpation , but the use of ultrasound has increased the cannulation success rate . This improvement , albeit significant , has not led to a very high success rate especially in trainees . A modified ultrasound technique for vascular cannulation ( dynamic needle tip positioning ) has been described for peripheral venous cannulation . We therefore assessed the success rate of this technique compared to the palpation technique for radial artery cannulation in adult surgical patients . METHODS : We enrolled patients who were having nonemergent operations that required a radial arterial catheter for intraoperative monitoring . Patients were r and omized to either palpation or dynamic needle tip positioning technique .  Arterial cannulation was performed by anesthesia residents or faculty members . The primary end point was successful cannulation on the first pass . Secondary end points were overall 5-minute success rate and number of attempts within 5 minutes . RESULTS : Two hundred sixty patients were evaluated . The first-pass success rate was 83 % in the dynamic needle tip positioning technique group ( n = 132 ) and 48 % in the palpation group ( n = 128 ; P < .001 ) ; relative risk was 2.5 ; 95 % confidence interval , 1.7–3.6 . The overall 5-minute success rate was 89 % in the dynamic needle tip positioning technique group compared to 65 % in the palpation group ( P < .001 ) , relative risk was 2.4 ; 95 % confidence interval , 1.2–1.6 . The number of skin puncture attempts was significantly more in the palpation group ( P < .001 ) . The median cannulation times and interquartile ranges were 81.5 ( 61–122 ) seconds in the dynamic needle tip positioning and 76 ( 48–175 ) seconds ( P = .7 ) in the palpation group . CONCLUSIONS : The use of the ultrasound-guided dynamic needle tip positioning technique increased the first and overall success rates compared to palpation in anesthesia residents and faculty members Background This study observed the efficacy of ultrasonic technique with out-of-plane orientation and in-plane guidance in radial artery puncture and cannulation in intensive care unit ( ICU ) shock patients to eluci date the effect of this technique on the security of cannulation . Material / Methods A total of 88 ICU shock patients , r and omized into a  palpation ( control ) group  and an ultrasound ( experimental )  group , received continuous intravenous sedation and analgesia . The palpation group patients underwent radial artery cannulation using the traditional palpation pulsation approach , and the ultrasound group patients underwent radial artery cannulation under out-of-plane orientation and in-plane guidance using an ultrasonic apparatus . Data were recorded and compared between the 2 groups . Results ( 1 ) The success rate of the first puncture in the ultrasound group and the palpation group was 80 % and 42 % , respectively ( P<0.05 ) . ( 2 ) The cannulation duration in the ultrasound group and the palpation group was 8.77±6.33 s and 28.7±26.33 s , respectively ( P<0.01 ) . ( 3 ) Incidence of hematoma and staxis around stoma in the ultrasound group was 2.5 % and 5 % , respectively , which was significantly lower than that in the palpation group , which was 20 % and 32.5 % , respectively ( P<0.05 ) . ( 4 ) Time to achieve the early goal -directed therapy in the ultrasound group and the palpation group was 306.73±39.98 min and 356.75±40.97 min , respectively ( P<0.01 ) . Conclusions Compared with the traditional method , radial artery cannulation with out-of-plane orientation and in-plane guidance is a quick and secure cannulation method and is appropriate for use in clinics Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more BACKGROUND Previous studies have shown ultrasound guidance (USG)for arterial cannulation being advantageous compared to palpation technique , but little is known about its performance by novices . OBJECTIVE This study was to compare the utility of USG radial artery cannulation with palpation technique in terms of success rate , real-time to placement , number of attempts and complications . MATERIAL AND METHOD After IRB approval , a r and omized prospect i ve study was performed November 2009-October 2010 . Ten third-year residents , having performed USG vascular catheterization as yet less than 3 times , were coached on the pork-phantom during a workshop for real time ultrasound-guided vascular access . For the study patients were r and omized to US-guided technique ( US-group ) and palpation ( P-group ) ; ten patients for each resident . RESULTS One hundred adult patients undergoing neurosurgery were enrolled . There were no statistically significant differences between US-group vs. P-group in success rate ( 78 % vs. 82 % ; p = 0.62 ) , time to success ( 60 ( 12.8 , 547.0 ) vs. 52 ( 6.9 , 639.0 ) sec ; p = 0.22 ) , and number of attempts ( 1 ( 1 , 4 ) vs. 1 ( 1 , 3 ) ; p = 0.79 ) . Most common complication was puncture hematoma ( US-group 26 % vs. P-group 24 % ; p = 0.82 ) . Success was defined as no change in catheterization site , performer and technique . CONCLUSION Regarding success rate , attended time , or number of attempts for radial arterial cannulation , we did not find any benefit of ultrasound guidance compared to palpation technique . Our findings were not in accordance to other trials . However , we have to consider operators in our study being in experienced in ultrasound-guided procedures but not in palpation techniques OBJECTIVES Ultrasound guidance for central venous catheterization  improves success rates and decreases complications when compared to the l and mark technique . Prior research has demonstrated that arterial and /or posterior vein wall puncture still occurs despite real-time ultrasound guidance . The inability to maintain visualization of the needle tip may contribute to these complications . This study aims to identify whether long-axis or short-axis approaches to ultrasound-guided vascular access afford improved visibility of the needle tip . METHODS A prospect i ve trial was conducted at a level I trauma center with an emergency medicine residency . Medical students and residents placed needles into vascular access tissue phantoms using long-axis and short-axis approaches . Ultrasound images obtained at the time of vessel puncture were then review ed . Primary outcome measures were visibility of the needle tip at the time of puncture and total time to successful puncture of the vessel . RESULTS All subjects were able to successfully obtain simulated blood from the tissue phantom . Mean time to puncture was 14.8 seconds in the long-axis group and 12.4 seconds in the short-axis group ( P = .48 ) . Needle tip visibility at the time of vessel puncture was higher in the long-axis group ( 24/39 , 62 % ) as opposed to the short-axis group ( 9/39 , 23 % ) ( P = .01 ) . CONCLUSIONS In a simulated vascular access model , the long-axis approach to ultrasound-guided vascular access was associated with improved visibility of the needle tip during vessel puncture . This approach may help decrease complications associated with ultrasound-guided central venous catheterization and should be prospect ively evaluated in future studies OBJECTIVES To identify success rates for radial artery cannulation in a pediatric critical care unit using either palpation or ultrasound guidance to cannulate the radial artery . METHODS A prospect i ve r and omized comparative study of critically ill children who required invasive monitoring in a tertiary referral center was conducted . All patients were r and omized by a stratified block of 4 to either ultrasound-guided or traditional palpation radial artery cannulation .  The primary outcomes were the first attempt and total success rates . RESULTS Eighty-four children were enrolled , with 43 r and omized to the palpation technique and 41 to the ultrasound-guided technique .  Demographic data between the groups were not significantly different . The total success and first attempt rates for the ultrasound-guided group were significantly higher than those for the palpation group ( success ratio , 2.03 ; 95 % confidence interval , 1.13 - 3.64 ; P = .018 ; and success ratio , 4.18 ; 95 % confidence interval , 1.57 - 11.14 ; P = .004 , respectively ) . The median time to success for the ultrasound-guided group was significantly shorter than that for the palpation group ( 3.3 versus 10.4 minutes ; P < .001 ) . Cannulation complications were lower in the ultrasound-guided group than the palpation group ( 12.5 % versus 53.3 % ; P < .001 ) . CONCLUSIONS The ultrasound-guided technique could improve the success rate and allow for faster cannulation of radial artery catheterization in critically ill children Objective : To determine whether ultrasound guidance increases the success rates , decreases the complication rates , and shortens the time to successful radial artery catheterization in infants and small children . Design : R and omized study . Setting : Single university-affiliated hospital . Patients : Infants and children weighing 3–20 kg , undergoing cardiac surgery for congenital heart disease . Intervention : We r and omly assigned the right and left radial arteries of patients undergoing arterial catheterization to ultrasound-guided technique versus the usual palpation technique . Measurements : The primary study endpoints were the rates of successful cannulation at first and within three attempts . The secondary endpoints were time to radial artery identification , number of attempts for successful cannulation , and rate of complications . Main Results : Compared with palpation , ultrasound-guided radial artery catheterization was successful in 76.3 % versus 35.6 % of first attempts and in 94.9 % versus 50.8 % of arteries after three attempts ( both comparisons , p < 0.01 ) . The median time [ interquartile range ] to identification of the arteries ( 18.5 seconds [ 11.25–27.25 ] vs 30 seconds [ 17.75–39.5 ] ) was significantly shorter ( p < 0.01 ) , the number of attempts [ interquartile range ] at successful cannulation ( 1 [ 1–1 ] vs 2 [ 1–2 ] ) was significantly fewer ( p < 0.01 ) , and the proportion of hematomas ( 5.1 % vs 25.4 % ) was significantly lower ( p < 0.01 ) in the ultrasound group than those in the palpation group . Conclusions : In infants and small children , ultrasound-guided radial artery catheterization was more successful and expeditious than the usual palpation technique Background and objective : In small children , the placement of arterial catheters can be technically challenging for even the most experienced anaesthetist . We investigated whether ultrasound imaging would improve the success rate and reduce time dem and and complications of radial artery cannulation . Method : In this prospect i ve r and omized study , we performed radial artery cannulation in 30 small children ( age 40 ± 33 months ) using two different techniques for localization of the vessel . In Group 1 ( n = 15 ) 
    Output:
    
Conclusions Ultrasound‐guided technique for RA access has higher first‐attempt success and lower failure rate compared with palpation alone , with no significant differences in access site hematoma or time to a successful attempt .
These findings support the routine use of US guidance for RA access