What is the test for appointing counsel to defend in a medical malpractice case?

After reviewing the petition, the magistrate judge appointed counsel and ordered an evidentiary hearing pursuant to our decision in Sparman v. Edwards, in which we expressed our belief that "a district court facing the question of constitutional ineffectiveness of counsel should . . . offer the assertedly ineffective attorney an opportunity to be heard and to present evidence." 154 F.3d 51, 52 (2d Cir. 1998) (per curiam). At the resulting hearing, the magistrate judge heard testimony from a medical expert and from defense counsel, who explained his trial preparation and strategy.