Comparison of ultrasound guided dorsal radial artery cannulation and conventional radial artery cannulation at the volar aspect of wrist: A randomized controlled trial

Comparison of ultrasound guided dorsal radial artery cannulationand conventional radial artery cannulation at the volar aspect of wrist: Arandomized controlled trial

 Arterial cannulation is a commonly performed invasive procedureused in operating room, intensive care unit, emergency department and incardiac catheterization laboratory. Arterial cannulation allows beat-to-beatblood pressure measurement, blood sampling for blood gas analysis and can beused for guiding fluid therapy in critically ill or surgical patients1, 2.Radial artery, being easily accessible because of its superficial location, isone of the most preferred sites for arterial cannulation and has a low rate ofprocedural complications from arterial cannulation3, 4. Classicallyradial artery cannulation is performed by digital palpation method at the volaraspect of the wrist. Complication of radial artery cannulation are bleeding,hematoma formation, infection, arterial thrombosis, pseudo-aneurysm formation,injury to the median nerve etc5. Though the complications areuncommon, some of them have serious implications.

Dorsal radial artery cannulation is a relatively less evaluatedtechnique and offers few advantages over classic radial artery cannulation. Thedorsal radial artery is located by palpation of the pulse on the dorsum of thehand, between the bases of the first and second metacarpals, in the"anatomical snuffbox." The palmar branch of the radial artery, whichcontributes to the superficial palmar arch, arises from the radial artery inthe volar side of the wrist before entering the anatomical snuffbox.Catheterizing the dorsal radial artery has the advantage of cannulating moredistally than with the traditional trans-radial approach, beyond the origin ofthe palmar branch. Avoiding trauma to this important collateral vessel couldreduce the risk of digital ischemia. Moreover, maintaining vessel integrityboth during and after cannulation could be advantageous when cannulating abranch located most distally from the aorta. Although the radial artery in thevolar area is favored for its superficial location, the dorsal radial artery isalso superficially palpable within the anatomical snuffbox. Moreover, whereasthe course of the superficial radial artery on the volar side can be altered byeven minor changes in wrist positioning, the dorsal radial artery is free fromsuch positional influences. As the dorsal radial artery resides in the anatomicalsnuffbox, it is firmly positioned between the first dorsal interosseous muscleand extensor carpi radialis longus muscle, so a catheter within this arterywill be in a stable position, with minimal risk of kinking or malpositioning,even after abrupt positional changes.

Aims & objectives

In this prospective randomized controlled trial, clinical utilityof dorsal radial artery cannulation will be compared with conventional radialartery cannulation at the volar aspect of wrist in terms of:

1.     First attemptsuccess rate (Primary outcome)

2.     Overallsuccess rate of cannulation

3.     Number ofattempt of success

4.     Time tocannulate the artery

5.     Time topuncture the artery

6.     Anycomplications related to the cannulation such as bleeding, thrombosis, hematomaformation etc.

Methods

Study design: Prospective randomized parallel group study

Study setting: Main operation theatre, AIIMS, New Delhi

Study population: Adult patients (aged between 18 to 65 years) ofeither sex and American Society of Anaesthesiologists physical status I or IIundergoing any surgery under general anaesthesia requiring radial arterialcannulation for anaesthesia and perioperative management will be recruited inthis study.

Exclusion criteria:

1.     Patients’refusal to participate in this study

2.     Patients withASA physical status III or more

3.     Patients withperipheral vascular diseases

4.     Patients withcoronary artery diseases

5.     Patientsundergoing emergency surgery

Randomization & blinding

Patients will be randomizedas per a computer generated random number table in the two following groups:

Group D (n=100): Dorsalradial artery will be cannulated under USG guidance by Seldinger technique

Group W (n=100): Radialartery will be cannulated at the volar aspect of wrist under USG guidance bySeldinger technique.

Patients’ randomization sequence will be kept inside an opaquesealed envelope and will only be handed over to the investigating team afterinduction of general anaesthesia. The operators who are cannulating radialartery will not be blinded to the technique being followed for obvious reason. Allcannulation will be done by either of the two investigators (SM or DKB) tomaintain uniformity. Outcome data will be collected the anaesthesiologists whoare not member of the investigating team.

Study protocol: Only patients requiring arterial cannulation foranaesthesia and perioperative management will be recruited in this study. Allpatients will be evaluated on the day before surgery by the anaesthesia team toassess their suitability for recruitment in this study. Preoperativeinvestigations including complete hemogram, serum electrolytes, renal functiontest will be recorded as per standard Institute protocol. Patients will bepremedicated with oral alprazolam 0.25mg and ranitidine 150 mg on the nightbefore surgery. In the operating room, an 18G intravenous cannula will besecured and standard monitoring as American Society of Anesthesiologists’recommendation will be attached. A thoracic or lumbar epidural catheter will beplaced when clinically indicated. General anaesthesia will be induced withintravenous fentanyl 2mcg kg; propofol 2-3 mg kg and tracheal intubation byappropriate size cuffed endotracheal tube will be facilitated by intravenousatracurium 0.5 mg kg. Anaesthesia will be maintained with volatile anaestheticagent (sevoflurane, isoflurane or desflurane) in air-oxygen (FiO2=0.5)targeting an end-tidal concentration of 0.8-1.0 of minimum alveolarconcentration and muscle relaxation will be achieved by intermittent boluses ofshort or inter-mediate acting muscle relaxant or their infusion.

After induction of general anesthesia, patients will be randomizedin two groups as per randomization number. Site of radial artery cannulationwill be decided as per randomization sequence and under all aseptic precautionsarea of cannulation will be draped. In patients belonging to group D, thedorsal radial artery will be located by palpation of the pulse on the dorsum ofthe hand, between the bases of the first and second metacarpals, in the "anatomicalsnuffbox." Then a small foot print linear USG transducer (SnositeTML25xp, 13-6 MHz) will be placed over the radial artery in transverse axis. Theartery will be located as hyperechoic circular pulsating structure between thetwo meta-carpal bones and USG transducer will be adjusted to keep the radialartery in the middle of the ultrasound screen. A 20G puncture needle will beused to cannulate the radial artery under ultrasound guidance in short-axisview. Once pulsatile blood flow is noted in the hub of the puncture needle andtip of the needle is visualized inside the radial artery, a J- tipped metallicguide wire of 0.53mm will be inserted in the arterial lumen and puncture needlewill be taken out. Next a 20G polyethylene catheter of 20cm length with wingedhub will be railroaded over the guide wire and the guide wire will be pulledout once the catheter is inserted. Position of arterial catheter will beconfirmed by pulsatile flow of bright red blood in the hub and it will beconnected with a pressure monitoring tubing for arterial blood pressuremeasurement. In patients belonging to the group W, radial artery will belocated 2-4cm proximal to the flexor crease of the wrist and the artery will becannulated in the methods described above.

When cannulation will be failed even after three attempts,patients will be marked as ‘unsuccessful’ and identified as failure of thetechnique.

Data collection: Following data will be collected unblindedanesthesiologists who are not a part of this study:

1.     Time tocannulate the artery (defined as time to localizing the artery in USG screen toinsert the catheter inside the artery)

2.     First attemptsuccess of cannulation

3.     First attemptsuccess of arterial puncture

4.     Number ofattempt required for successful cannulation

5.     Number ofattempt required for successful arterial puncture

6.     Overallsuccess rate

Sample size estimation and plan for data analysis

With best of our knowledge, no previous study has evaluated dorsalradial artery cannulation till date. To obtain normally distributed data, n=100patients will be recruited in each group in this study. Demographic data willbe expressed as mean ± SD (age, weight, height) or proportion (sex and ASAphysical status). Arterial cannulation time will be expressed as median andinter-quartile range.

Review of literature

Radial artery is the most frequently chosen site of arterialcannulation for its superficial location. Arterial cannulation is a safeprocedure and most of the complications such as bleeding, arterial spasm, temporaryarterial occlusion are minor in nature. However, some serious complicationssuch as digital ischemia due to arterial thrombosis, injury to the mediannerve, carpal tunnel syndrome and pseudo-aneurysm are also reported5.Amongst this nerve injury and arterial occlusion leading to ischemia are thetwo most important complications, which can be reduced with dorsal approach ofradial artery cannulation. The digital arteries supplying the fingers arisefrom the superficial palmar arch. The palmar branch of the radial artery, whichcontributes to the superficial palmar arch, arises from the radial artery inthe volar side of the wrist before entering the anatomical snuffbox.Catheterizing the dorsal radial artery has the advantage of cannulating moredistally than with the traditional transradial approach, beyond the origin ofthe palmar branch. Avoiding trauma to this important collateral vessel couldreduce the risk of digital ischemia.

   References

1.     Scheer B, Perel A, Pfeiffer UJ. Clinical review: complicationsand risk factors of peripheral arterial catheters used for haemodynamicmonitoring in anaesthesia and intensive care medicine. Crit Care. 2002;6:199-204.

2.     Gu WJ, Wu XD, Wang F, Ma ZL, Gu XP. Ultrasound Guidance FacilitatesRadial Artery Catheterization: A Meta-analysis With Trial Sequential Analysisof Randomized Controlled Trials. Chest. 2016;149:166-79.

3.     Brzezinski M, Luisetti T, London MJ. Radial arterycannulation: a comprehensive review of recent anatomic and physiologicinvestigations. Anesth Analg. 2009;109:1763-1781.

4.     Jolly SS, Yusuf S, Cairns J, et al. Radial versus femoralaccess for coronary angiography and intervention in patients with acutecoronary syndromes (RIVAL): a randomised, parallel group, multicenter trial.Lancet. 2011;377:1409-1420.

5.    Scheer B,Perel A, Pfeiffer UJ. Clinical review: complications and risk factors ofperipheral arterial catheters used for haemodynamic monitoring in anaesthesiaand intensive care medicine. Crit Care. 2002;6:199-204.

6.    Choi S, ParkJM, Nam SH, Kim EJ. Cannulation of the dorsal radial artery: an underused, yetuseful, technique. Korean J Anesthesiol. 2014;67:S11-2.