Abstract
The search for relevant literature focused on empirical literature articles that contained information on the success rates of the performance of anesthesia personnel in the insertion of radial arterial catheters in the pre-operative holding area and after induction of anesthesia. However, the paucity of research in the comparison of success rates on the two occasions led to the option of selecting closely related articles and including theoretical literature in addition.
The review of theoretical literature will explore the indications, the vessels used and why some are not used, equipment needed for insertion, complications possible, and troubleshooting issues concerning the use of the radial artery catheters. Empirical literature was limited in the subject and the main focus will be on radial artery catheterization before anesthesia. The search for the subject of radial artery catheterization after induction of anesthesia has not elicited any results. The impression created from the selected articles is that complications in radial artery cannulation are rare. Marked debility and ischemia are the consequences if a delay in diagnosis occurs. Contributory factors for the ischemia are several.
Review of relevant theoretical literature
The procedure in hemodynamic monitoring using a radial artery catheterization has been detailed as a common monitoring tool in the intensive care unit by Garretson, a Nurse Manager of the ICU and Step-down Unit at the Richmond Heights Hospital in Ohio. (2005) The arterial catheter is an invasive device used in the intensive care unit (Durbin, 2001) It has the potential to cause damage if handled by inexperienced staff (McGhee and Woods, 2001).
If successfully applied, the catheterization is life-saving (Garretson, 2005). It is the transducer, a portion of the tubing that is fluid-filled that conveys the information about the blood pressure through to the bedside monitor (Smith et al, 2004). The pressure waveforms and the numerical readings thus become available. They change with the heartbeat. The arterial catheters vary according to the vessel being used.
Powner (2000), who belongs to the Department of Neurosurgery, University of Texas, has described how organ procurement coordinators use arterial catheters for determining blood pressure and for taking samples of blood. (2000) Organ procurement techniques use arterial catheters for measuring arterial blood pressure directly and for taking blood samples for biochemical analysis (Powner, 2000). The main caution that organ transplantation coordinators ensure is to convince the people concerned about quality assurance. Potentially transplantable organs should be removed from donors without any injury from catheter insertions.
The donor, therefore, is not catheterized just for the two functions that the catheter does. Blood pressure can be examined at the bedside using an oscillometric device. Blood samples can be taken otherwise except for blood gas analysis (BGA). However, BGA is not necessary if the pulse oximeter is reliable (Powner, 2000). The point to be noted here is that injury is possible in arterial catheterization and that catheterization is not done in the donor’s organ so that the risk from it is zero. The health of the donor’s organ cannot be compromised at all. Complications are reduced by optimal positioning of the site: the radial artery is best reached when the hand is supinated or in a palm upward position with slight dorsiflexion by using a towel under the head of the radius. The pulse must be palpable.
Repositioning may sometimes be necessary to get the optimal pulse strength. Wide cleansing of the site of puncture is done. The apparel for performing surgery is donned. No chance of infection is allowed. Palpating the pulse and stabilizing it, with the level of the needle outward, the needle enters the skin at a 45o angle from the horizontal. This angle allows easy entry into the artery. The Seldinger method using a wire has a lesser failure rate.
The wire is advanced through the needle into the artery till it has covered the length of the catheter that will follow. If the wire cannot advance, cautiously withdraw and change direction slightly and reinsert the wire. Older donors may not be easy to catheterize because of atherosclerotic plaques. Once the wire is in place, the needle is removed. Dilators are not used with artery catheterization. The procedure is the same if a catheter-over-needle assembly is used. Slight twirling may help the advancement of the catheter which is then sutured in a position
The femoral artery if used can be punctured below the inguinal ligament. The axillary artery can be felt by palpating across the axilla but its cannulation is more difficult. The Allen’s test may be done when the radial artery is used especially when doubtful about the collateral circulation however the significance of it has not been clarified (Bur et al, 2000). The dorsal pedis over the anterior midfoot is good for BGA but not for blood pressure determination. The Doppler device can confirm the site of the artery apart from palpation (Levin et al, 2003).
A practical tip for successful cannulation through the radial artery has been provided by Arya and Subramanyam, 2 anesthetists from the premier institute, Post Graduate Institute of Medical Education and Research, Chandigarh, India. (2009) Failing to understand that the needle is the leading part of the needle-catheter assembly is the cause of most catheterization failures (Mark and Slaughter, 2005). The metallic tip of the needle prevents the recognition of the arterial puncture.
Arya and Subramanyam (2009) have tried to explain how the failure can be prevented with a practical “tip”. After the radial artery has been entered, it is wise to wait for the pulsatile blood to flash in the metallic needle hub. This is the indication to reduce the angle and advance the needle-catheter assembly a few mm. so that the catheter has entered the artery lumen. The needle is slightly withdrawn while the catheter is held in place creating a small space between them where the blood flash is seen. If there is no blood flash, a doubt arises as to whether the artery has been punctured at all. (Arya and Subramanyam, 2009)
This is the problem that always causes failure. This can be solved by slowly pulling out the metallic needle till its tip can be seen through the catheter. If counter puncturing of the artery has occurred, the tip will show multiple blood rings or cylindrical columns of blood will be seen along the catheter.
The needle-catheter assembly can be slightly withdrawn and a re-entry made into the lumen of the artery. Watching the blood rings move to the hub end, one can be sure that the artery lumen is about to be entered; this is the point where the anesthetist has to be careful. Again the blood flash between the metallic needle and the catheter is the indicator of the correct entry into the lumen. Colleague anaesthesiologists who adopted this method found 90% success when compared to the previous 60% (Arya and Subramanyam, 2009).
Adachi et al performed catheterization with Insyte-A, an innovative instrument developed by BD Medical, Japan on the principle of the wire-guided cannula (2008). The instrument is held in a pen holding style or ”cigarette holding manner” for penetration. The position has an advantage in lessening the angle between the needle and the artery which is important for the penetration (Adachi et al, 2008). The moment the puncture is made, the catheter can be eased into the artery without any waiting time to check for the flash of blood.
Review of relevant research
Researches using radial artery catheterization and case reports have been included in this section. An old patient of 61 years of age who had renal cell cancer and had nephrectomy for it came to the hospital with septicemia (Wallach, 2004). He had associated diabetes mellitus, hypertension with peripheral vascular disease, and coronary artery disease. Broad-spectrum antibiotics and vasopressors were administered. Monitoring catheters and a cannula were introduced into the left radial artery and the procedure was done without any difficulty. Twelve hours later, ischemic changes were noted on the hand and the cannula was removed.
Both lower extremities showed ischemic changes and the skin exhibited mottling. The mottling was not found on the right hand. Tissue necrosis was noted and amputation of the thumb followed. Proper history had not been elicited in this case. The coronary bypass had been done and there was a chance of radial artery harvesting having been done then. (Wallach, 2004) It would have been wise to find out which artery had been used for the harvesting or pedaling or flaps.
These would have left only one artery for perfusion of the hand which would have adapted through anomalous vasculature. Wallach points out that complications could have been avoided if anomalous vasculature due to procedures or congenital causes had been eliminated. Ischemia could also have occurred due to diabetes, hypertension, use of heparin, warfarin, or aspirin.
These could produce a hematoma at the site of puncture. Vasopressor agents also could have initiated the ischemia in this patient. The precautions that could have been taken were correct medical history taking, physical examination of each hand, and Allen’s test. Some researchers think that this test does not predict ischemia. Some advise pulse oximetry or digital plethysmography. Hand dominance must be understood and the dominant hand should be avoided to prevent damage to it (Wallach, 2004).
The risks of cannulation of the radial artery must be minimized. The risk of complications is diminished by using a 20-gauge or smaller cannula ( Bedford and Wollman, 1973 cited in Wallach, 2004). Long-term use of the catheter raises the risk of complications. (Evans and Kerr, 1975 cited in Wallach, 2004). If contraindications exist, other arteries must be opted for: the opposite radial artery, femoral artery, dorsal artery of the foot, the brachial artery, the axillary, or the temporal could be used. (Baker, Chunprapaph and Nyhus, 1976 cited in Wallach, 2004)
The dorsal artery will not be a good choice: it could even be absent. (Youngberg and Miller, 1976 cited in Wallach, 2004) The femoral artery will be the best. A sympathetic block can induce vasodilatation in a person on vasopressors. Arterial duplex Doppler sonography can delineate areas of occlusion and flow. Angiography can also help (Wallach, 2004).
Radial arterial catheterization was studied in 1473 neonates and infants by Schindler et al. (2005) before surgery for congenital heart defects. The brachial artery was the alternate site. Serious damage through ischemia was not seen. Temporary arterial occlusion was noted in 5 of 1473 patients. The rate of local infection ranged from 0.5% to 2.3 % in the three groups which had been formed based on weight. The local hematoma was seen in some cases but they did not produce problems. In general, the incidence of complications was negligible. Schindler et al recommended the use of the brachial artery as a safe alternative to radial artery cannulation. This study provided evidence of the safety of the procedure.
Direct arterial blood pressure monitoring provides “moment-to-moment changes in a patient’s hemodynamic status. Blood loss can cause hypovolaemia which in turn decreases the oxygen delivery to the tissues which causes compensatory peripheral vasoconstriction. A hypotensive episode follows and is easily detected. However, the disadvantage is that the hand may go into ischemia during the hypotensive phase. This is what happened in the case of a 14-year-old boy. (English and Maye, 2003). This boy had surgery for posterior spinal fusion from T5 through L3 for severe idiopathic adolescent sclerosis.
He went into hypotension 3 hours into the surgery. Fluid resuscitation was done for the blood loss during surgery. The cyanotic hand was noticed when he was transferred to the post-anesthesia room. Efforts were made to warm the hand after drawing blood for analysis and then removing the artery line. Digital pressure was applied to hinder the formation of a hematoma. A warm compress was provided to increase vasodilatation and enhance collateral circulation. Moderate ischemia was diagnosed due to extreme hypotension and radial artery occlusion which could have occurred. The patient recovered within 20 hours.
His hand became normally perfused by then. (English and Maye, 2003) The ischemia could have been due to thrombosis at the site, embolus from a proximal area, excessive trauma because of multiple attempts to cannulate, large catheters, earlier vascular disease, hyperlipoproteinemia, or a lengthy period of hypotension. Whatever the cause, timely diagnosis and intervention save the patient from disastrous complications.
Digital gangrene has been reported in another patient, a 51-year-old man with diagnosed gastric adenocarcinoma, who had thrombocytosis (Rehfeldt, 2000). The distal part of his index finger developed gangrene following radial artery catheterization of the same side and was autoamputated. Laboratory studies indicated the marked thrombocytosis but general examination failed to reveal arterial occlusive disease.
Infection is a rare but horrible complication of radial artery catheterization. For hemodynamic monitoring, radial artery catheterization was done for a 60-year-old lady under strict aseptic conditions. The lady showed inflammation at the site after 72 hours (Ortega, Rengasamy, and Lewis, 2002). Staphylococcus aureus was diagnosed to be the causative organism of cellulitis and dynamic management with surgical debridement, aggressive antibiotic therapy, and skin grafting had to be done.
A comparison was made in a randomized trial of 272 patients between the patients who were already on catheters (control group) and new patients where absolute sterile precautions were taken during the catheterization. (Rijnders et al, 2003). The colonization incidence was 20.2 cases per 1000 in the standard-of-care group while it was 15.8 cases in the control group (p>.1). This meant that arterial catheterization-related infection was found in 3 patients in the standard-of-care group while 7 were found in the control group (p>.1). The conclusion was that sterile barrier precautions did not prevent colonization or infection (Rijnders et al, 2003).
More has to be done by way of research to find better measures to be undertaken before and during artery catheterization to prevent the problem of infection. Antimicrobial or antiseptic-coated catheters could be a solution but researches have to be done.
Harkin and his colleagues report a case with a potentially fatal complication, a radial artery mycotic pseudoaneurysm following an artery catheterization (2002). This pseudoaneurysm is formed at the site of cannulation due to a disruption of the wall of the artery. Hemorrhage also could occur in such artery wall damage. This patient had hemophilia A or classical hemophilia. The incidence of the pseudoaneurysm in hemophilia has not been reported (Harkin, 2002).
Sherwin and colleagues compared the effects of lidocaine injection with lidocaine iontophoresis on the pain associated with radial artery cannulation. (2003) The patients were delegated into two groups randomly. The 10 cm. visual analog scale was used to record the pain scores just after the cannulation. No difference in the mean pain scores was seen. The quality of analgesia produced by both was similar. (Sherwin, 2003)
A cohort study was performed over 4 years in the Washington University School of Medicine to elicit the “effect of education on the incidence of catheter-associated bloodstream infection in a medical intensive care unit” (Zack et al, 2004). The education program consisted of lectures to nurses and medical professionals, posters and factsheets exhibited outside the patient rooms, and an education module on the lines of the Hospital Infection Control Practices Advisory Committee. The aim behind the program was to make the personnel aware of the latest optimal practices in catheter insertion, catheter-associated bloodstream infection, and evolving a strategy for educating the physicians (Zack et al, 2004). Efficient education can be eye-openers to newer techniques and provide a forum for the sharing of practical tips.
The success rates of using a wire-guided cannula over a nonguided one have been investigated by Ohara and his colleagues on 100 adult patients who needed an artery line in the operating room (2007). The success rates were found similar in both methods but the inexperienced operators found it easier with the wire-guided cannula.
A comparison has been made of “ultrasound-guided and blindly placed radial arterial catheters” (Shiver, 2006). The time to set the catheter in position, the number of tries before the catheter was placed properly, the sites used and complications seen were the areas compared in this interventional study. If the blind placement was not successful 3 times, the ultrasound-guided technique was resorted to. Statistical analysis was appropriately done with Fisher’s exact, Mann-Whitney, and Student’s t-tests. It was found that the ultrasound-guided technique was successful more often and took less time to achieve. (Shiver, 2006)
It is interesting to note that the radial artery catheter is being used for peripheral blood progenitor cell collection or leukapheresis in pediatric cases (Bambi et al, 2003). The authors have concluded that “peripheral radial artery catheters are safe, minimally invasive, and provide steady, high flow rates” and apt for patients needing leukapheresis.
Summary
As illustrated from the review of literature, the information on radial artery catheterization has been obtained from case reports and theoretical literature; researches are fewer in number. The procedure is of use as a continuous monitoring tool in the intensive care unit, before cardiac surgery including for congenital heart defects in infants and neonates, organ procurement procedures (but preferably not in the donor), and leukapheresis.
The requirements for the success of the procedure have been understood from the literature. A good device like the Insyte-A or the needle–catheter assembly, a good technique like the wire-guided cannula, experienced operators, adequate selection of cases, complete history-taking, correct selection of artery, ensuring that the circulation is normal, keeping the dominant hand untouched, observing and timely diagnosing of ischemia or known complications and dynamic management of ischemia or other complications will contribute to a successful procedure. The literature has not mentioned the procedure while under anesthesia.
This study intends to close the gap and investigate and compare the success rates when the procedure is performed in the two situations: in the pre-operative room and while under anesthesia. The factors which contribute to the success will also be explored.
References
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