Physician extenders "can help one physician care for more than one patient at a time," says Karen Sibert, MD, President of the California Society of Anesthesiologists and a professor at UCLA. In her field, physician anesthesiologists rely on the support of advanced practice practitioners and assistants — either certified registered nurse anesthetists (CRNA) or certified anesthesiologist assistants (CAA). "They are exactly analogous to what PAs are for a primary doctor or surgeon," she explains. They are trained in a medical, not nursing, model, and work directly under the supervision of physician anesthesiologists. The CAAs, she says, "provide an opportunity for the physician anesthesiologist to focus on emergencies and saving lives, and not some of the lower level tasks such as initial screening and paperwork."