Static Venous Pressure Measurement by Access Alert in Detecting Vascular Access Stenosis / 대한신장학회잡지

BACKGOUND: K/DOQI guideline recommends measurement of vascular access blood flow and static intra-access pressure (SIAP) as important vascular access monitoring methods. Vascular access blood flow is measured by ultrasongraphic dilution method or Doppler sonographic examination. But these two examinations are expensive and the former needs special apparatus and the latter has the limitation of inter- and intra-observer variability. This study was performed to evaluate the utility of SIAP measured by Access Alert in detecting vascular access monitoring in hemodialysis (HD) patients. METHODS: Ninety-two patients on chronic HD via arteriovenous fistulas (AVF) and grafts (AVG) were included in this study. Mean age was 5513 and the number of man was 34. Sixteen patients had AVG. We measured both dialysis venous pressure (DVP) and SIAP. SIAP was measured by Access Alert (Medisystems, Seattle, WA) via arterial and venous canulation into vascular access and then static intra-access pressure ratio (SIAPR) was calculated by SIAP/MAP (mean arterial pressure. Venography was performed to find venous stenosis in patients who had abnormal levels of SIAPR. RESULTS: Arterial and venous SIAPRs in patients with AVG were higher than those in patients with AVF, respectively (arterial line:0.69+/-0.24 vs. 0.29+/-0.18, pp<0.001, venous line:0.60+/-0.23 vs. 0.23+/-0.16, p<;0.001). Of the total 92 patients, 30 patients had abnormal SIAPR. We performed venography in 19 out of these 30 patients. Of the 19 patients, 17 patients had stenotic venous lesions in which 14 patients had severe stenotic lesions and required radiologic intervention. In 14 patients with severe stenotic lesions, only 2 patients showed abnormal DVP and other patients showed normal DVP. CONCLUSION: The measurement of static intra-access pressure by Access Alert is simple and effective in detecting vascular access stenosis.

The Comparison of Access Alert and Drip Chamber Methods in Measuring Static Venous Pressure in Hemodialysis Patients / 대한신장학회잡지

BACKGOUND: Static venous pressure (SVP) by Access Alert method has been known to be more strongly predictive of venous stenosis than dialysis venous pressure (DVP). This study was performed to compare Access Alert and drip chamber methods in measuring static intra-access pressure in hemodialysis patients. METHODS: Eighty-one patients on chronic hemodialysis via arteriovenous fistulas (AVF) or grafts (AVG) were included in this study. We measured SVP using both drip chamber and Access Alert methods. In drip chamber method, we measured venous drip chamber pressure (P(DC)) and the height from the venous needle to the top of the blood in the venous drip chamber (delta H). The pressure difference (delta P(H)) was estimated as delta H (cm) x 0.76 and SVP in AVF (PAVF) was calculated as sum of PDC and delta P(H). In Access Alert method, we measured SVP directly through venous cannulation of vascular access. Finally static intra-access pressure ratio (SIAPR) was calculated by SVP divided mean arterial pressure (MAP). RESULTS: Mean SVP measured by Access Alert and drip chamber methods were 0.28+/-0.21 (0.08-0.96) and 0.35+/-0.18 (0.13-0.92), respectively. Mean SIAPR by Access Alert method well correlated with mean SIAPR by drip chamber method (r=0.885, p< 0.001). CONCLUSION: This study suggests that Access alert method correlates highly with drip chamber method in measuring SVP and it can be useful method in detecting vascular access monitoring.