1 Divisions of Critical Care and Interventional Pain Management, Department of Clinical Science, Kaiser Permanente Bernard J. Tyson School of Medicine, South San Francisco, CA.
2 Regional Anesthesia and Acute Pain Medicine, Department of Clinical Science, Kaiser Permanente Bernard J. Tyson School of Medicine, South San Francisco, CA.
3 University of Kansas Medical Center, Department of Anesthesiology, Kansas City, KS. Electronic address: bflynn@kumc.edu.