The currently used double lumen femoral catheters seem not competent to this machine due to blood recirculation. As a result, a new simplified sampling method will be provided for a completely automatic RCA machine with the function of iCa automatic monitoring online. If there is a high degree of consistency to two groups, the iCa data tested from arterial line blood sample can be used to replace that from peripheral vein, finally the cumbersome sampling by venous puncture from peripheral vein can be left out and be substituted by taking from arterial line. The difference of iCa levels was assessed between arterial line and peripheral vein, which if, was caused by recirculation. Blood samples were taken both from the arterial line before predilution and the peripheral vein synchronously, and in turn, were tested immediately. In order to simplify the cumbersome operating procedures of blood sampling, a new type of double lumen catheter was located in the patient’s femoral vein, in which the minimum distance from the inner venous port to the inner arterial port was lengthened to 6 cm long, then, extracorporeal circulation connected via arterial and return lines. However, the complexity of the regimen is the major hurdle preventing widespread application for example, frequent peripheral vein puncture for blood sampling. Regional citrate anticoagulation (RCA) for CRRT is associated with a longer filter life span and fewer bleeding events. With rapid popularization of blood purification, the morbidity of bleeding or high risk of bleeding is gradually increasing in patients who required continuous renal re- placement therapy (CRRT) in ICU. Conclusion: In clinical practice, the data of iCa concentration from arterial line can be used to replace that from peripheral vein when the new type of double-lumen femoral catheter is placed in femoral vein.

Systemic calcium concentration was achieved in the ideal range. None induced bleeding, or bleeding aggravated. None of the patients developed citrate toxicity or metabolic alkalosis. Statistics showed that the difference of iCa concentration between arterial line group and the peripheral vein group was not significant (P = 0.9), there is a high degree of similarity between the iCa concentration of arterial line blood and the peripheral venous blood. Results: 28 times of RCA-CRRT were performed on17 AKI and CRF patients with active bleeding or at the high risk of bleeding 336 blood samples were collected. The iCa concentration data of two groups were analyzed to observe the difference between iCa concentration levels in the arterial line and in peripheral vein the anticoagulant effect of RCA and possible complications were observed, such as bleeding, clottings and hypocalcaemia. Blood samples were synchronously collected from the arterial line before the infusion of citrate replacement fluid and from the peripheral vein. Replacement solution contained citrate, zero Ca 2+, zero bicarbonate, low Na +.

The minimum distance from the venous port to the arterial port was greatly lengthened. The new type of double-lumen tube had a greater distance from the inner venous ports to the inner arterial ports than current tubes. Methods: A new type of double-lumen femoral catheter was used instead of the current tubes. Objectiv e: To replace the peripheral venous puncture for blood sampling with taking blood samples extracorporally from arterial line before predilution during RCA-CRRT performed.

Double lumen catheter