Hazards of radial-artery catheterization

Intraarterial catheter diameter and dynamic response of arterial pressure monitoring system: a randomized controlled trial

The dynamic response (DR) of the arterial pressure monitoring system (APMS) may depend on the intraarterial catheter (IAC) diameter. We hypothesized that adequate DR would be more common when using a smaller IAC. We compared the DR of the AMPS (Auto Transducer™) between three IACs (BD Angiocath Plus™) with different diameters. 353 neurosurgical patients were randomized into three groups undergoing catheterization with a 20-, 22-, or 24-gauge IAC: 20G (n = 119), 22G (n = 117), and 24G (n = 117) groups, respectively. The DR, which depends on the natural frequency and damping coefficient, was divided into four types: adequate (primary outcome measure), underdamped, overdamped, and unacceptable. The frequency of intraoperative IAC malfunction was noted. Adequate DR was observed more frequently in the 22G and 24G groups than the 20G group (13.7% and 15.4% vs. 4.2%, P = 0.011 and 0.004, respectively). The frequency of underdamped DR was higher in the 20G group than the 24G group (86.6% vs. 69.2%, P = 0.001), whereas overdamped DR was more frequent in the 24G group than the 20G and 22G groups (6.0% vs. 0.0% and 0.0%, P = 0.007 and 0.014, respectively). IAC malfunctioned more frequently during surgery in the 24G group than the 20G and 22G groups (15.4% vs. 0.0% and 1.7%, P < 0.001 and P < 0.001, respectively). The frequency of adequate DR was low regardless of the IAC diameter. Nonetheless, in terms of DR and IAC malfunction, a 22-gauge BD Angiocath Plus™ was more suitable for invasive blood pressure monitoring with Auto Transducer™ than a 20- or 24-gauge BD Angiocath Plus™. Registration Registry: ClinicalTrials.gov. Registration number: NCT03642756. Date of Registration: July 27, 2018.

[Radial artery occlusion ofter coronarography: is it really a problem?]

The use of transradial access for cardiac procedures has increased worldwide over the past two decades. Despite the many advantages this technique offers, there remains some concern that radial artery occlusion, a potential complication of radial cannulation, might lead to significant ischemic sequelae in the hand. This paper reviews the major causes, its possible consequences and the strategies for its prevention and treatment. It appears however from multiple studies that there is little or no correlation between radial occlusion and symptomatic hand ischemia.

Thrombotic complications after radial arterial line placement in systemic sclerosis: A case series

OBJECTIVE

To demonstrate potential thrombotic complications after radial arterial line placement in patients with scleroderma.

METHODS

This is a retrospective case series of 4 patients with scleroderma who were hospitalized in the intensive care unit (ICU) requiring invasive hemodynamic monitoring and developed severe complications after radial arterial line placement. We reviewed their medical records to assess their laboratory findings and clinical presentations.

RESULTS

All 4 patients met the 2013 ACR/EULAR criteria for systemic sclerosis and had a radial arterial line placement in the setting of invasive hemodynamic monitoring. Overall, 2 of 4 patients had arterial line placement during surgery; while 1 patient had it placed for invasive blood pressure monitoring during an ICU admission for renal crisis; and 1 patient had arterial line placement during cardiac resuscitation, but before administration of vasopressor support. In all, 3 of 4 patients had major ischemic events including digital gangrene, hand auto-amputation, and below-elbow amputation. Among all, 1 patient had temporary hand ischemia with recovery of perfusion with immediate arterial line removal within 24 hours.

CONCLUSIONS

Radial arterial line placement may trigger critical ischemic events in scleroderma patients. This experience suggests that placement of radial lines needs to be thoughtfully weighed prior to insertion in patients with scleroderma, and alternative options should be carefully considered.

Can the Anesthesiologist Use the Radial Artery for Monitoring After Transradial Artery Catheterization?

The use of transradial coronary angiography and intervention is growing because of its advantages over the femoral approach. However, the small size of the radial artery can contribute to complications. We present a case of an in situ access complication of transradial coronary artery catheterization. It is important for the anesthesiologist to know about the short-term and long-term consequences of this intervention, which could lead to narrowing of the artery even beyond the site of puncture. Understanding these changes could help anesthesiologists make better decisions about using the radial artery for monitoring after transradial coronary artery catheterization procedures.

Open surgical management of complications from indwelling radial artery catheters

BACKGROUND

Cannulation of the radial artery is frequently performed for invasive hemodynamic monitoring. Complications arising from indwelling catheters have been described in small case series; however, their surgical management is not well described. Understanding the presentation and management of such complications is imperative to offer optimal treatment, particularly because the radial artery is increasingly accessed for percutaneous coronary interventions.

METHODS

We conducted a retrospective review to identify patients who underwent surgical intervention for complications arising from indwelling radial artery catheters from 1997 to 2011.

RESULTS

We identified 30 patients who developed complications requiring surgical intervention. These complications were categorized into ischemic and nonischemic, with 15 patients identified in each cohort. All patients presenting with clinical hand or digital ischemia underwent thrombectomy and revascularization. Complications in the nonischemic group included three patients with deep abscesses with concomitant arterial thrombosis, two with deep abscesses alone, and 10 with pseudoaneurysms. Treatment strategy in this group varied with the presenting pathology. Among the entire case series, three patients required reintervention after the initial surgery, all in individuals initially presenting with ischemia who developed recurrent thrombosis of the radial artery. There were no digital or hand amputations in this series. However, the overall in-hospital mortality in these patients was 37%, reflecting the severity of illness in this patient cohort. Three patients who were positive for heparin-induced thrombocytopenia antibody had 100% mortality compared with those who were negative (P = .04, Fisher exact test). In-hospital mortality was higher in patients presenting with initial ischemia than in those with nonischemic complications (53% vs 20%; P = .06). Among 10 patients who presented with pseudoaneurysms, five (50%) were septic at presentation with positive blood cultures, and six (60%) had positive operating room cultures. Staphylococcus aureus was identified as the causative organism in all of these patients.

CONCLUSIONS

Complications of radial artery cannulation requiring surgical intervention can represent infectious and ischemic sequelae and have the potential to result in major morbidity, including digital or hand amputation and sepsis, or death. Although surgical treatment is successful and often required in these patients to treat severe hand ischemia, hemorrhage, or vascular infection, these complications tend to occur in critically ill hospitalized patients with an extremely high mortality. This must be taken into consideration when planning surgical intervention in this patient cohort. Finally, radial arterial cannulation sites should not be overlooked when searching for occult septic sources in critically ill patients.

Radial artery cannulation: a comprehensive review of recent anatomic and physiologic investigations

Consistent anatomic accessibility, ease of cannulation, and a low rate of complications have made the radial artery the preferred site for arterial cannulation. Radial artery catheterization is a relatively safe procedure with an incidence of permanent ischemic complications of 0.09%. Although its anatomy in the forearm and the hand is variable, adequate collateral flow in the event of radial artery thrombosis is present in most patients. Harvesting of the radial artery as a conduit for coronary artery bypass grafting, advances in plastic and reconstructive surgery of the hand, and its use as an entry site for cardiac catheterization has provided new insight into the collateral blood flow to the hand and the impact of radial arterial instrumentation. The Modified Allen's Test has been the most frequently used method to clinically assess adequacy of ulnar artery collateral flow despite the lack of evidence that it can predict ischemic complications in the setting of radial artery occlusion. Doppler ultrasound can be used to evaluate collateral hand perfusion in an effort to stratify risk of potential ischemic injury from cannulation. Limited research has demonstrated a beneficial effect of heparinized flush solutions on arterial catheter patency but only in patients with prolonged monitoring (>24 h). Conservative management may be equally as effective as surgical intervention in treating ischemic complications resulting from radial artery cannulation. Limited clinical experience with the ultrasound-guided arterial cannulation method suggests that this technique is associated with increased success of cannulation with fewer attempts. Whether use of the latter technique is associated with a decrease in complications has not yet been verified in prospective studies. Research is needed to assess the safety of using the ulnar artery as an alternative to radial artery cannulation because the proximity and attachments of the ulnar artery to the ulnar nerve may potentially expose it to a higher risk of injury.

Incidence and outcome of radial artery infections following cardiac surgery

BACKGROUND

Radial artery infections secondary to catheterization for blood pressure monitoring are rare but potentially serious complications. The objective of the study was to evaluate the incidence, the risk factors and the evolution of radial artery infections following cardiac surgery.

METHODS

A retrospective review of 8300 patients undergoing cardiac surgery between 1998 and 2002 at the Montreal Heart Institute (MHI) was undertaken. All patients with superficial radial artery infections, infected radial artery pseudoaneurysms, and arterial catheter-related bacteremia were considered using prospective global surveillance of all nosocomial infections over the study period by an infection control nurse.

RESULTS

Thirteen patients with radial infections were encountered (0.2%) with bacteremia occurring in 9 patients (0.15%). Five patients developed infected radial artery pseudoaneurysms (0.05%) and 5 patients developed subsequent sternal wound infections. Two patients died in their early postoperative evolution. Mean patient age was 67 years old and mean duration of cannulation was 5.8 days. Only 1 patient had diabetes. Seven of 13 patients were positive for Staphylococcus aureus (54%). All patients had undergone cardiopulmonary bypass (CPB) for various procedures. All superficial infections responded well to antibiotic therapy. Early surgical intervention is essential in cases of infected radial artery pseudoaneurysms.

CONCLUSIONS

The postoperative state and cardiopulmonary bypass put patients at risk for infectious complications. Strict systematic changing of arterial lines on a timely basis is unwarranted in our opinion. A high suspicion index, aggressive surgical treatment of bacterial arteritis and appropriate intravenous antibiotics are essential to improve the prognosis.

Continuous pH monitoring using the Paratrend 7 inserted into a peripheral vein in a patient with shock and congenital lactic acidosis

The authors present a 25-year-old woman who was admitted to the ICU for treatment of shock, respiratory failure, and acidosis related to congenital lactic acidosis from pyruvate dehydrogenase deficiency. To aid in ongoing management of the metabolic acidosis, the Paratrend blood gas monitoring sensor was inserted through a peripheral venous site to provide a continuous measurement of pH and partial pressure of carbon dioxide (Pco2). With the venous insertion of the Paratrend, a clinically useful correlation with arterial blood gas values was noted. Linear regression analysis of the pH values from the venous blood gas analyses and the Paratrend monitor revealed r2 = 0.71 with p = 0.001 and r2 = 0.78 with a p = 0.0003 for the Pco2 values. Our preliminary experience suggests that venous placement of the Paratrend monitor can be used to provide clinically useful, continuous measurement of pH and Pco2.

Ruptured pseudoaneurysm complicating an infected radial artery catheter: case report and review of the literature

The authors present the 16th case of a pseudoaneurysm forming at the site of an infected radial artery catheter and only the third case that presented with rupture and hemorrhage requiring emergent operative repair. Radial artery catheters are quite safe, and most infections can be treated effectively with line removal and intravenous antibiotics. However, two factors correlate strongly with the subsequent development of pseudoaneurysms. Infection with Staphylococcus aureus was seen in 15 of 16 cases, and persistent signs of infection lasting more than 48 hours after the institution of antibiotic therapy and line removal were seen in 16 of 16 cases. Therefore, patients with S. aureus radial artery line infections with persistence of infection more than 48 hours after the induction of treatment are at high risk and should be observed closely for signs of pseudoaneurysm formation. Once a pseudoaneurysm has formed, surgical repair is required. Most recommend ligating the artery if there is pulsatile backbleeding from the distal stump and Allen's test shows good perfusion of the hand by the ulnar artery.

Ischaemia of the Hand in Infants Following Radial or Ulnar Artery Catheterisation

Radial and ulnar arterial catheterisation have become frequently used methods of monitoring in neonatal and pediatric intensive care units. Minor complications are common and temporary ischaemic changes in the form of blanching are well described. However, permanent ischaemia in the infant has rarely been reported. This series is the first in the hand surgery literature to address the issue of digital ischaemia following radial artery catheterisation in the infant population and adds three to the six previously reported cases in the English literature. One patient had fingertip necrosis to the distal interphalangeal joint level of the middle, ring and little fingers, while two other patients required amputation at the carpometacarpal joint level.

Transcutaneous monitoring of blood gases: is it comparable with arterialized earlobe sampling?

Researchers are increasingly looking for reliable non-invasive methods of assessing blood gas concentrations, and several new techniques have recently become available. Values derived using arterialized earlobe samples have been found to be comparable with conventional arterial samples, and recent studies have compared transcutaneous blood gas analysis with the traditional arterial samples and found a reasonable level of agreement in particular for the partial pressure of carbon dioxide. There are no data comparing oxygen and carbon dioxide partial pressures (pO2, pCO2) derived from arterialized samples with one of the newer transcutaneous techniques. We therefore simultaneously studied arterialized earlobe blood gas samples and values for pO2 and pCO2 obtained by a transcutaneous monitor (TINA, Radiometer, Copenhagen) in 26 subjects with varying blood gas values. There was a close agreement between the two methods for assessment of pCO2 [mean difference (95% C.I.) between transcutaneous and earlobe values 0.25 kPa (-0.004, 0.5 kPa)], but not for pO2 [1.71 kPa (0.35, 3.07 kPa)]. Similarly, the limits of agreement were narrow for pCO2 compared to those for pO2 (-0.98, 1.47 kPa and -6.44, 3.02 kPa respectively). We conclude that transcutaneous measurement of pCO2 using the TINA is acceptable in the research setting, whereas assessment of pO2 cannot reliably be made using this technique.

Blood pressure measurement during exercise: a review

This review summarizes research dealing with the validity of commonly used methods for measuring systemic blood pressure during exercise. Arterial blood pressures measured from within peripheral arteries exaggerate systolic blood pressures because of wave form reflection but provide representative mean and diastolic pressures of the central arterial circulation. Manual and automated sphygmomanometry are the best noninvasive indirect methods of blood pressure measurement to estimate ascending aorta systolic pressures; however, both methods significantly underestimate diastolic pressures at rest and during exercise. The error in diastolic pressure measurement increases with increasing exercise intensity. The accuracy of many indirect noninvasive devices for blood pressure measurement at rest and during exercise can be questioned because of the use of unsuitable criterion methods. Ascending aorta pressures should ideally be used as a gold standard or criterion method for blood pressure measurement during exercise and instrument/method validation. However, given the constraints of varied criterion standards and current recommendations for blood pressure measurement, the following units were found to be acceptable devices for measuring systolic blood pressure during exercise: Accutracker II, A&D TM 2421, Colin 630 (auscultation), Critikon 1165, and possibly the Paramed 9350.

Invasive line placement in critically ill patients: do hemostatic defects matter?

BACKGROUND

Blood components are often given prophylactically before the placement of invasive lines in patients with coagulation defects. Little, however, is known about the epidemiology of defects in these patients. The purpose of this study is to ascertain what proportion of intensive care patients who receive invasive lines have hemostatic defects, what actions are taken by physicians to correct these abnormalities before invasive line insertion, and what the incidence is of bleeding complications after invasive line placement.

STUDY DESIGN AND METHODS

Charts were retrospectively reviewed for 490 intensive care patients in whom 938 arterial, pulmonary artery, and central venous lines were placed.

RESULTS

At least one defect in hemostasis was documented for 388 patients (41%) before line placement, with 253 (27%) of these patients evidencing severe abnormalities. Seventeen percent of patients had no preprocedure laboratory evaluation. Trauma patients showed the highest numbers of abnormalities in hemostatic testing, but medical patients had more-severe defects. The occurrence of isolated abnormal laboratory values did not predict bleeding, but a score derived from a consideration of multiple defects did. Correction of the abnormalities was attempted in 37 percent of patients with hemostatic defects. Sixteen patients had bleeding complications, but only two had complications that were life-threatening. None of the complications were fatal.

CONCLUSION

Invasive lines are used frequently in patients with hemostatic defects, often without any attempt to correct the abnormalities. Nevertheless, rates of hemorrhage are low and appear to be closely related to the level of experience of the physician rather than to defects in hemostasis. These findings suggest that the use of blood components for preprocedure correction of hemostatic defects is not necessary, except in those patients who have the most severe hemostatic abnormalities.

Noninvasive evaluation of the collateral circulation to the hand

OBJECTIVE

To compare four methods of evaluating collateral blood flow to the hand.

METHODS

The hands of 74 volunteers on the faculty or staff of a university hospital were studied prospectively. Only subjects without known peripheral vascular disease were included. Four tests were used in random order to assess radial and ulnar artery flow. Results of the assessments using the modified Allen's test, pulse oximetry, plethysmography, and laser Doppler perfusion monitoring were compared.

RESULTS

No interrupted palmar arch was found. The modified Allen's test was normal in all cases. Pulse oximetry detected a 5% incidence of noticeably reduced blood flow in one artery compared with the other artery. This dominance of one artery was identified in 69% of the hands by plethysmography. The laser Doppler noted a dominant artery in 64% of the hands. Plethysmography and the laser Doppler disagreed in their findings in only 9% of the hands evaluated. Numerical values of blood flow, attainable only by the laser Doppler, were significantly lower upon occlusion of the radial vs the ulnar arteries (p < 0.05; paired t-test).

CONCLUSION

All of the tests provide information about the collateral circulation to the hand. Only the laser Doppler provides quantitative blood flow. Further studies involving subjects most at risk for post-cannulation ischemic injury are needed to guide the clinical application of these findings.

Delayed ischaemia of the hand necessitating amputation after radial artery cannulation

We present a case of ischaemic hand injury in a patient, who had 95% occlusion of both the ulnar and radial arteries, after atraumatic placement of a left radial artery catheter. The presence of cigarette burns on the dorsum of the hand was highly suggestive of vascular compromise. There were no signs of vascular compromise after placement of the arterial line which was removed 24 hr later. Ten days after placement the patient complained of pain with ensuing ischaemic changes resulting in necrosis of the finger tips and eventual amputation of the hand. We recommend using other sites of arterial access such as axillary or superficial temporal artery in patients with severe peripheral vascular disease.

Infected radial artery pseudoaneurysms occurring after percutaneous cannulation

During a ten-month period in 1988 at our institution, we identified three infected radial artery pseudoaneurysms (RAPAs) associated with arterial lines. A retrospective chart review to 1983 identified three additional cases, all occurring in 1986. In the six-year period of 1983 through 1988, during which approximately 12,500 radial artery catheters were placed, the incidence of RAPA formation was 6/12,500 (0.048 percent). Five of the six cases were associated with Staphylococcus aureus infection. The duration of radial artery cannulation was significantly longer in patients who developed a pseudoaneurysm (12.5 days) than in those patients who did not suffer this complication (4.3 days). Patients in whom infected RAPAs occurred also tended to be older (mean, 71.6 years) than the average age (54 years) for all patients admitted to the intensive care unit (ICU). They also tended to have long stays in the ICU prior to development of RAPA, the shortest stay being 11 days and the average being 51 days. Risk factors for the development of this complication may include advanced age, longer duration of catheterization and hospitalization, and infection with S aureus.

[Comparison of thrombogenic risk between teflon and polyethylene in prolonged catheterization of the radial artery]

This prospective study was designed to compare the rates of radial artery thrombosis after long-term cannulation with two different types of catheters with similar size. It included 101 patients, randomly assigned to group A (n = 51, 61 +/- 17 years, 80% males), and group B (n = 50, 55.8 +/- 18 years, 54% males). Patients in group A were cannulated with a polyethylene catheter (Leader Cath. 115-09), and those in group B with a Teflon catheter (Plastimed Seldicath). The diagnosis of arterial occlusion was made by way of a bedside angiography performed before catheter removal. An X-ray was taken after injection of 10 to 15 ml Hexabrix through the catheter. The two groups were similar with regard to anthropometric parameters (except for the sex ratio), cannulation technique, used drugs, duration of cannulation, pathological events during the stay in intensive care. The rate of complete arterial thrombosis in the two groups was similar (10%). There were no differences in the rates of partial thrombosis (51 vs. 36%, n.s.) and of absence of thrombosis (39 vs. 54%, n.s.). The rate of arterial thrombosis did not vary with the duration of cannulation, nor with age, sex, systemic heparinization, vascular collapse, cannulation technique. However, 4 polyethylene catheters were infected on removal (coagulase negative Staphylococcus, Pseudomonas aeruginosa) versus only one Teflon catheter (Staphylococcus epidermidis). In conclusion, the biocompatibility of Teflon and polyethylene catheters was found to be similar.

Noninvasive blood pressure monitoring at the finger for studying short lasting pressor responses in man

The study of vasoactive agents in man often requires accurate measurement of short-lasting changes in blood pressure. Using a noninvasive photoplethysmographic device (Finapres), the authors investigated in normotensive subjects whether rapid increases in blood pressure can be assessed precisely by monitoring finger blood pressure continuously. Six volunteers were studied on two consecutive days. On the first day, increasing doses of angiotensin I were injected intravenously with the aim to find a test dose which raised systolic blood pressure by 25 to 40 mm Hg. After oral administration of a placebo, the same test dose was injected repeatedly over the next 24 hours. On the second day, the subjects took either 6.25 (n = 3) or 25 mg (n = 3) captopril PO and the serial administration of the test dose of angiotensin I was continued for the next 4 hours. After placebo intake there was a good reproducibility of the blood pressure response to angiotensin I with a coefficient of variation of 15 +/- 4.5% (Mean +/- SD, n = 6). Captopril caused a dose-dependent inhibition of the pressor effect of angiotensin I. These data indicate that noninvasive blood pressure monitoring at the finger represents a useful tool to study short-lasting blood pressure changes produced by vasoactive agents in man.

Reliability of pulse oximetry during exercise in pulmonary patients

To evaluate the reliability of pulse oximetry during exercise, we studied 101 patients primarily with chronic pulmonary diseases. Three devices were used on different patients. Radial arterial blood was sampled at rest and maximal exercise simultaneously to pulse oximetric determination. Measured blood oxygen saturation was significantly different from noninvasive saturation at rest and also at exercise for each device. Nevertheless, changes in pulse oximetry from rest to exercise were significantly correlated with measured saturation for all three devices. Direction of changes in saturation from rest to exercise was correctly evaluated by transcutaneous oximetry in all but six instances where changes were less than 4 percent. Although measured and transcutaneous saturations are significantly different, we conclude that pulse oximetry reliably estimates changes in arterial saturation between rest and exercise for a clinical purpose. None of the three tested devices was better compared with the others in estimating saturation changes at exercise.

[Risk of thrombosis in prolonged catheterization of the radial artery: comparison of 2 types of catheters]

The thrombosis rate after long-term cannulation of the radial artery was assessed prospectively in 48 intensive care patients randomly assigned to groupe A (polyethylene Leader-Cath 115-09 catheter; n = 50, aged 55 +/- 20 years, 74% male patients) or groupe B (Teflon Viggo Floswitch 4441 catheter; n = 48, aged 58.6 +/- 16 years, 73% male patients). Bedside angiography was carried out with 10 to 15 ml Hexabrix before removal of the catheter. The two groups were similar with regard to anthropometric parameters, used drugs, pathological events during the stay in ICU, arterial cannulation technique and its duration. There was no case of clinically significant ischaemia. The rate of X-ray total arterial thrombosis was 20% in group A, and 2% in group B (p less than 0.01). There was no difference in the rate of partial thrombosis (54% vs. 41.7% respectively, NS) and of lack of thrombosis (26% vs. 56.3% respectively, NS). The overall rate of thrombosis was greater in group A than in group B, but not significantly (74% vs. 43.7% respectively). The duration of arterial cannulation did not influence the rate of thrombosis. However it was higher in males of Group A than in those of Group B (p less than 0.01), when heparin was not given (p less than 0.05); when vaso-active drugs were used (p less than 0.05); and when the time required for cannula insertion was greater than 5 min (p less than 0.01). It is concluded that Teflon catheters are more biocompatible than polyethylene catheters.

Incidence and duration of total occlusion of the radial artery in newborn infants after catheter removal

The incidence and duration of total occlusion of the radial artery after catheter removal was determined using repeated Doppler flow measurements. Thirty-two newborn infants with birthweights ranging from 945 g to 3890 g (median 1935 g) and gestational age ranging from 26 to 40 weeks (median 32 weeks) were studied. In 20 out of 32 infants (63%), complete occlusion of the radial artery occurred. The number of occlusions were not related to birthweight, gestational age or duration of cannulation. In all infants, blood flow in the radial artery resumed within 1-29 days after catheter removal. The duration of occlusion was directly related to the duration of cannulation and inversely related to birthweight. This study demonstrates a high frequency of total occlusion of the radial artery in newborn infants after percutaneous radial artery cannulation. In the majority of infants with a radial artery catheter, blood flow to the tissue distal to the cannulation site is dependent solely on the existence of an adequate arterial palmar collateral circulation.

Incidence of forearm and hand ischaemia related to radial artery cannulation in newborn infants

We report the incidence of transient and permanent ischaemia of the forearm and hand caused by radial artery cannulation in a series of 98 newborn infants. Birth weight ranged from 550 to 3920 g (median 1600 g) and gestational age ranged from 26 to 40 weeks (median 31 weeks). In 4 of the 98 infants transient ischaemia of the forearm and/or hand occurred. In three infants the onset of ischaemia was probably related to thrombo-embolic events and in one infant to inadequate palmar collateral circulation. Permanent ischaemic damage with tissue loss did not occur in any infant. It is concluded that permanent ischaemic damage to the forearm and/or the hand with tissue loss, attributable to radial artery cannulation, is seldom encountered in newborn infants. In minimizing the risk of ischaemia, careful assessment of palmar collateral circulation prior to cannulation and of all factors predisposing to the onset of ischaemia is essential. Immediate removal of the catheter at the earliest signs of ischaemia, is essential to prevent ensuing tissue loss.

Nosocomial infections associated with long-term radial artery cannulation

From January 1987 to December 1987, 193 radial artery cannulations were performed in 112 patients (87 males, 25 females; mean age = 57.5 years). The mean duration of cannulation was 6.45 days. After removal, the tip of the catheter was cultured using a semiquantitative culture technique: 164 catheters were cultured and positive results were seen in 37 cases (22.5%); 98 samples of infusate were cultured. Positive results were observed in 23 cases (23.5%). No bacteriological correlation was found between these two culture results. During the study, no catheter-related or infusate-related bacteraemia was detected. It is concluded that nosocomial infections associated with long-term radial artery cannulation are not commonly seen, in particular no catheter or infusate-related bacteraemia occurs even if the duration exceeds 4 days.

Radial artery cannulation guided by Doppler ultrasound

A technique to enhance difficult percutaneous radial artery cannulations using Doppler ultrasound is described. A series of 12 patients (nine hypotensive and three normotensive patients with poorly palpable or absent radial pulses) was assembled and the radial arteries were cannulated using standard intravenous catheters and a hand-held Doppler ultrasound device. Localization and cannulation of the arteries was facilitated by noting the characteristic sounds using the Doppler. Eleven of the 12 patients had successful cannulation of the radial artery. In one case the artery was localized but the catheter could not be advanced. No complications were encountered. It was concluded that the use of a common Doppler ultrasound on selected patients with poor peripheral pulses may facilitate percutaneous radial artery cannulations and minimize the number of catheter punctures before successful placement.

A comparison of radial, brachial, and aortic pressures after cardiopulmonary bypass

Previous investigations have identified falsely low radial artery pressures after cardiopulmonary bypass (CPB). The present study investigates the relationship among radial, brachial, and aortic arterial pressures in 33 cardiac surgical patients following CPB. Two minutes after separation from CPB, clinically important (greater than or equal to 10 mmHg) underestimation of systolic aortic pressures occurred in 17 of 33 (52%) radial artery catheters, while occurring in seven of 33 (21%) brachial artery catheters. Radial artery mean pressure underestimated aortic mean pressure by greater than or equal to 5 mmHg in 21 of 33 (61%) patients two minutes after CPB, while an equivalent aortic-to-brachial artery mean arterial pressure difference occurred in nine of 33 (27%) patients. The incidence of aortic-to-radial mean arterial pressure differences greater than or equal to 5 mmHg decreased to 40% (four of ten patients) by ten minutes after CPB, although interpretation is complicated by decreased availability of aortic pressure measurements. Multivariate analysis failed to identify factors predisposed to central-to-peripheral pressure gradients. Radial and brachial arterial pressures were compared both before and after CPB in all 33 patients. Brachial artery systolic and mean pressures were higher than corresponding radial artery measurements two minutes after CPB (P less than 0.05), followed by gradual resumption of a normal brachial-to-radial pressure relationship over 60 minutes. Either vasospasm in the brachial and radial arteries or profound arteriolar vasodilation in the upper extremity might cause the observed central-to-peripheral arterial pressure differences. The progressive central-to-peripheral decrease in mean arterial pressure favors the latter mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Single arterial puncture vs arterial cannula for arterial gas analysis after exercise. Change in arterial oxygen tension over time

In an attempt to find the least invasive, safest, easiest, and cheapest method of obtaining resting and exercise samples of arterial blood, a comparison was made between samples from an arterial needle puncture and an arterial cannula. This study demonstrated that samples of arterial blood may be obtained by radial arterial puncture both at rest and during exercise in practically all cases without morbidity. Samples from arterial needle puncture provide the same results as those from arterial cannulas. In the very rare patient in whom arterial puncture during maximal exercise is unsuccessful, the arterial oxygen pressure (PaO2) measured at 10 seconds after exercise correlates very well with the PaO2 at maximal exercise, and the 15-second value correlates nearly as well. Arterial cannulas are needed in the infrequent case when arterial puncture is not accomplished during maximal exercise and the 10-second or 15-second PaO2 decreases from the resting value. In this instance, determination of the exact extent of the hypoxemia requires an exercise sample obtained by cannula; however, the decrease in PaO2 obtained by arterial needle puncture at 10 or 15 seconds will be all that is needed many times to make a clinical decision. Values obtained at 20 seconds after maximal exercise reflect less of the exercise measurement and cannot be used; however, all episodes of significant hypoxemia (PaO2 less than 60 mm Hg) were captured by the analysis at 20 seconds after exercise.

Local tissue oxygenation following radial artery cannulation

The effect of radial artery cannulation on local tissue oxygenation and acid-base balance was studied in 20 patients. Using capillary samples drawn from each thumb, a significant difference was observed between capillary PO2 on each side (p less than 0.001), with the higher PO2 on the cannulated side. There were no significant differences between sides in terms of [H+] or PCO2. It is considered that the differences in capillary PO2 were due to local tissue vasodilatation. The presence of chlorbutol in the sodium heparin flushing solution is implicated as the causative factor. Further study of 20 patients using preservative-free heparin demonstrated no significant differences between cannulated and non-cannulated sides in terms of capillary PO2, PCO2 or [H+]. Sodium heparin with chlorbutol appears to improve local tissue oxygenation and is recommended for use in flushing solutions for invasive arterial monitoring.

Blood flow in the radial artery before and after arterial puncture

A study was carried out on seven patients to determine whether sub-clinical changes occurred in the blood flow in the radial artery following uncomplicated arterial puncture. An ultrasonic technique was used, and it was demonstrated that no changes take place in the blood flow, measured 15 min after puncture.

Radial artery cannulation and ischaemic damage: a review

A review of the literature concerning ischaemic complications following radial artery cannulation suggests that the Allen test has little predictive validity. Other methods of assessing the ulnar collateral circulation are discussed.

Assessment of digital blood flow and palmar collateral circulation. Allen's test vs. photoplethysmography

Collateral circulation of the hand and digits was evaluated in 20 healthy male volunteers using a modified Allen's test and photoelectric plethysmography. A borderline (7-14 sec) Allen's test was present in 12.5% and 2.5% required more than 15 seconds for thenar flush. Photoplethysmography was then used to compare the relative contributions of ulnar artery flow to total arterial flow into the hand. This ratio, (ulnar/total) was termed the flow index (FI). Average FI for the first digit (thumb) was 0.59, and for the second digit (index) was 0.64. The FI difference between the first digit and that of the third, fourth and fifth digits was statistically significant (p less than 0.01). The FI difference between the second digit and the third, fourth and fifth digits was also statistically significant (p less than 0.05). These results imply that Allen's test may be misleading, indicating adequate collateral circulation when in fact collateral blood flow to the digits may be poor or nonexistent.

Spontaneous retrocarpal radial artery thrombosis: a report of two cases

Two patients with spontaneous retrocarpal radial artery thrombosis are reported. Both patients had numbness and cold intolerance of the thumb and index finger and one patient had splinter hemorrhages. Angiography revealed identical occlusions of the radial artery over a 2.5 cm segment dorsal to the wrist. Both patients had complete palmar arches. Flow from the ulnar artery was sufficient to prevent frank necrosis of the thumb but not to prevent ischemic symptoms. Both patients were successfully treated by resection of the area of thrombosis and interpositional vein grafting by use of microsurgical techniques. Symptoms resolved after operation in both cases. Follow-up examinations 3 months and 5 1/2 years later revealed continued graft patency.

[Prolonged catheterization of the radial artery. Prospective evaluation of the thrombogenic and infectious risk]

The rates of thrombosis and infection were studied in 102 patients who underwent 107 radial artery cannulations. A Leader cath, ORX cannula (Vygon) was placed using Seldinger's method. It was continuously perfused with an heparinized 5% dextrose solution via an Intraflo fixed upon an arterial catheter. The cannulae were used for arterial pressure monitoring and measuring arterial blood gases. Before removing the catheter, a forearm arteriography was realized with 20 ml Hexabrix. Bacterial examination and culture were carried out on the cannula tips. 70 men and 32 women (mean age: 50 +/- 17 years) were studied. Mean duration of cannulation was 9 +/- 7 days (range: 1-34 days). Complete or partial radial artery thrombosis occurred in 85%. Complete thrombosis occurred more frequently in women (84%) than in men (54%) (p less than 0.05). There was no correlation between thrombosis and duration of cannulation (9.9 +/- days for thrombosis and 7.9 +/- 4.3 days without thrombosis). Bacterial cultures of cannula tips were positive in 24% of cannulations. Pathogenic bacilli grew in only 9%. Infected cannulas were in situ for 9.9 +/- 7 days against 8.9 +/- 6.7 days for the non-infected cannulas (NS). There was no correlation between infection and radial artery thrombosis. The use of another material (silicone, Teflon) must be studied in order to decrease the occurrence of thrombosis.

[Anesthesia and intensive care in cardiac surgery. Activity at the French centers in 1982]

A national survey was carried out to inquire about the practice of anaesthesia and surgical intensive care in cardiac surgery in French hospitals. In 1982, 15,797 surgical procedures with cardiopulmonary bypass were collected; 1,360 and 555 were performed in children and infants respectively. Coronary surgery accounted for 46% of the total. For the same time interval, 2,554 operations without cardiopulmonary bypass were done. Postoperative care was supervised by anaesthesiologists in most of the French centres. The duration of stay of patients in intensive care units increased as the unit's activity decreased. With the exception of arterial blood pressure monitoring, there was no consensus on the method or the extent of monitoring of patients undergoing cardiac surgery. A Swan-Ganz catheter was only used in 18% of cases. Neuroleptanalgesia was the anaesthetic technique most often used.

Percutaneous arterial cannulation in children. Concurrent and subsequent adequacy of blood flow at the wrist

For percutaneous arterial monitoring in children, the Medicut (polypropylene) is an appropriate choice of cannula. Morbidity associated with its use is low. We studied blood flow and clinical signs relating to 70 arterial cannulations in 62 patients. In the few patients exhibiting flow disturbances either whilst the cannula was in situ or following decannulation, we observed no associated clinical signs of vascular insufficiency of the forearm, wrist or digits. Also, most patients showed normal, antegrade blood flow past the cannula in situ and following decannulation. Eight patients showed retrograde flow which, in six cases, spontaneously reverted to normal whilst the child was still in hospital. The results of this study increased our confidence in the appropriateness, safety and ease of use of these polypropylene cannulae in children where peripheral arterial vessel diameters are small.

[Doppler velocimetric evaluation of the reliability of Allen's test for radial artery catheterization]

The result of Allen's test was compared with the variations in the Doppler flow recording of the thumb artery after compression of the radial artery in 76 volunteers. In five cases, manual compression let to a disappearance systolic flow, showing an absence of collateral ulnar circulation. In fifteen cases, the systolic flow was greatly reduced in the thumb. It is interesting to find that 14.6 per cent of the subjects have their two hands in a different classification (asymmetric subjects). In 99.34 per cent of the cases the results of these two methods was the same. The routine use of Allen's test before radial artery catheterization is fully justified by these results.

Aortography by countercurrent injection via the radial artery in infants with congenital heart disease

Aortography by countercurrent injection into the radial artery as performed for analysis of aortic arch anomalies in 12 infants with congenital heart disease. Eleven aortograms were obtained without complications, but one failed. Coarctation of the aorta, patent ductus arteriosus, aberrant origin of the right subclavian artery, interrupted aortic arch, anomalous origin of the right pulmonary artery from the ascending aorta, and hypoplastic ascending aorta were demonstrated by this method. Patency of the reconstructed aortic arch was confirmed in the postoperative study of the case of interrupted aortic arch. Aortography by countercurrent injection via the radial artery affords an easy, safe, and simple bedside means for analysis of aortic arch anomalies without retrograde arterial catheterization. The latter is occasionally complicated by thrombosis of the artery in small infants.