To determine risk factors associated with failure of arterial catheter insertion.
The study took place in the medical intensive care unit of a large urban teaching hospital. We analyzed 92 consecutive arterial catheter attempts by internal medicine house staff and critical care fellows over a five-month period beginning November 20, 2004. All patients 18 years of age or older requiring arterial catheters were included. We constructed a database that included patient characteristics (gender, body mass index, age, level of consciousness, mean arterial pressure, coagulation parameters, platelet count), procedure characteristics (indication, time of procedure, line site, use of ultrasound, number of skin punctures), post-graduate year of operator and post-graduate year of supervisor. Associations between characteristics and failure were analyzed by means of chi-square. Characteristics significantly associated with failure were entered into a multivariate logistic regression analysis.
There were 92 arterial catheter attempts. Femoral arteries comprised 25/92(27%) of the attempts and radial arteries 67/92(73%). The indications were hypotension 49/92 (53%), frequent blood draws 31/92(34%) and hypertension 12/92(13%). Interns attempted 63/92(68%), residents 24/92(26%) and fellows 5/92(5%) catheters. Ultrasound was used for 6/92(7%) of attempts. Patients were unconscious for 22/92(24%) of attempts. Failure was recorded for 26/92(28%) attempts. Female patients had a significantly higher failure rate than male patients (24/56 (43%) vs. 2/36 (6%), p<0.001). Body mass index, age, level of consciousness, mean arterial pressure, coagulation parameters, platelet count, indication for procedure, time of procedure, catheter site, use of ultrasound, number of skin punctures, post-graduate year of operator and post-graduate year of supervisor were not significantly associated with failure. After multivariate regression analysis, the gender of the patient remained statistically significant.
Female patients had significantly higher failure rates for arterial line attempts than male patients. Although not investigated in this study, a possible explanation could be smaller arterial size in female patients.
The increased failure rate for female patients should be considered when arterial catheters are planned.
Taro Minami, None.