The AACN Procedure Manual for Critical Care, 6th ed., 2011, states that although surgically created AV fistulas had been used in the past for CRRT, they are not recommended for CRRT access because of increased rates of injury, bleeding and infection (p. 1023), and the manual references National Kidney Foundation: KDOQI clinical practice guidelines for vascular access: update 2006, Am J Kidney Dis. 2006; 48:S176-S307.

The manual also references Uchino S, et al. Continuous renal replacement therapy: a worldwide practice survey. Intensive Care Med. 2007;33:1563-70.
Of a cohort of 1006 ICU patients treated with CRRT at 54 ICUs in 23 countries, Table 2 (p. 1566) shows that only 1 patient (0.1%) had continuous arteriovenous hemodialysis as the mode for RCCT.

A search of PubMed for continuous renal replacement therapy and access did not identify any studies published in the United States that specifically described using AVF for the access.