Introduction 1 2 3 4 5 6 7 8 Material and methods The PubMed, Medline Express and Winspirs databases (publication years 1978-2001) were searched to identify pertinent articles. The keywords 'artery catheter', 'radial artery catheter', 'femoral artery catheter', 'axillary artery catheter', 'catheter complication', 'hemodynamic monitoring' and 'peripheral methods' were used. We reviewed the papers and identified further articles from the references of the papers found in the initial search. We reviewed all studies concerning the use of radial, femoral, axillary, brachial, ulnar, dorsal pedis, tibial posterior and temporal artery catheters for haemodynamic monitoring that dealt with complications and risk factors in adults. We excluded studies conducted in the paediatric patient population. We opted not to perform statistical analyses because the data selection of the published reports do not follow the same criteria, and most of them give no specific information regarding patient population, catheter material, cannulation technique and times. Therefore, comparison between studies and statistical analyses are unlikely to be valid. Results We identified 78 studies that met our criteria. Radial artery 1 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 17 10 Generally, temporary occlusion of the artery has no serious sequelae. Permanent occlusion of the radial artery appears to be rare because it was reported in only four patients (mean incidence 0.09%). 33 34 35 36 1 37 38 39 40 41 42 43 44 45 46 47 48 Femoral artery 2 17 18 19 49 50 51 52 53 54 55 56 56 17 57 Axillary artery 3 54 55 58 59 60 61 54 59 Other sites for arterial cannulation Other less frequently reported cannulation sites are the brachial, dorsal pedis, ulnar, tibial posterior and temporal arteries. 62 63 24 54 64 29 65 66 67 68 Further studies 4 49 69 70 71 69 n n n 49 n n n n 70 70 71 5 52 54 72 73 74 75 76 77 78 52 72 73 74 75 76 77 54 78 Risk factors A further objective of the present review was to consider risk factors that might have impacted on complication rates. Thrombotic complications 79 80 3 81 5 10 14 22 25 11 14 11 5 5 14 21 14 5 5 14 21 13 14 14 5 9 14 16 25 Infectious complications 82 78 83 Escherichia coli Pseudomonas aeruginosa 84 85 78 83 86 87 83 83 88 89 90 Discussion 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 91 5 9 16 92 93 94 95 96 97 98 99 Other major complications such as pseudoaneurysm and sepsis were reported to occur in a mean of 0.09% and 0.13% of cases, respectively. 56 52 53 71 71 64 100 101 102 103 64 100 101 102 103 101 3 Other reviewed arteries employed for catheterization, such as the brachial, dorsal pedis, ulnar, tibial and temporal arteries, have been used without serious complications, but published reports of their use are limited. Conclusion Incidence rates for major complications such as permanent ischaemic damage, sepsis and pseudoaneurysm formation are low and similar for the radial, femoral and axillary arteries. They occur in fewer than 1% of cases. On the basis of the present systematic review we can conclude that serious complications of the radial, femoral and axillary artery are rare, and that arterial cannulation is a relatively safe procedure. Nevertheless, one must be aware of the possible serious complications that might arise. Therefore, it is important to use an arterial catheter only when it is indicated and to select carefully the best cannulation site individually for each patient, because the different cannulation sites have their specific advantages and attendant risks. Competing interests UJP is President of Pulsion Medical Systems AG, and AP is on the medical advisory board of Pulsion Medical Systems AG, whose PiCCO product uses a femoral arterial line.