(Hogan) Associate Professor, Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin.
(Prost) Research Associate, Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin.
(Kulier) Research Associate, Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin.
(Taylor) Assistant Professor, Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin.
(Liu) Staff Anesthesiologist, Virginia Mason Medical Center, Seattle, Seattle, Washington.
(Mark) Associate Professor, Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin.
Received from the Medical College of Wisconsin, Milwaukee, Wisconsin. Submitted for publication December 18, 1995. Accepted for publication February 23, 1996. Supported by Mr. and Mrs. Joseph Uihlein, Jr.
Address correspondence to Dr. Hogan: Department of Anesthesiology, Medical College of Wisconsin, 8700 West Wisconsin Avenue, Milwaukee, Wisconsin 53226.