RESUMO
BACKGROUND: Continuous arterial blood pressure monitoring is a highly effective method in an operation and the intensive care unit. However, the accuracy of the monitoring system could be influenced by the radius and longitude of the catheter. This study was executed to examine the effects of the radius and longitude of a catheter. METHODS: Forty-two pediatric patients scheduled to undergo open heart surgery were selected. After induction of anesthesia, the radial artery pressure was measured by a 22-gauge (1 inch) catheter and the femoral artery pressure was measured by a 20-gauge (1.16 inch) catheter, 22-gauge catheter and 20-gauge (12 cm) catheter in succession. Influences of the radius and longitude were analysed respectively. All values are expressed as mean +/- SD and analysed using the paired t-test; P < 0.05 was considered significant. RESULTS: The systolic pressure of the 20-gauge (1.16 inch) catheter was higher than that of the 22- gauge (1 inch) catheter. The systolic pressure of the 20-gauge (1.16 inch) catheter was higher than that of the 20-gauge (12 cm) catheter. Mean and diastolic pressures were low in the 20-gauge (1.16 inch) catheter, compared with the 20-gauge (12 cm) catheter. CONCLUSIONS: Shorter and/or larger radius catheters could increase the pulse pressure in pediatric patients.