WASHINGTON, Oct 14 - St. Louis Federal Reserve Bank President William Poole said on Tuesday the trend rate of U.S. productivity growth may have picked up, which would require higher real interest rates over time to keep inflation down. "There is a distinct possibility that the underlying pace of productivity growth has increased again," Poole said in remarks prepared for delivery at Bryant College in Smithfield, Rhode Island. "If so, and if the (Fed's policy-setting committee) does not make appropriate policy adjustments, inflation could drift away from current low levels." However, Poole said he was comfortable with the current stance of Fed policy, which has the benchmark overnight lending rate at a 45-year low of 1 percent. "My best guess is that the current stance of policy makes adequate allowance offsetting the risk that the current low inflation will turn into a period of deflation, and Fed vigilance over the longer run will, I believe, keep inflation under control," said Poole, who will move back into a voting position on the Fed's policy-making panel next year.//