Clinical examination with emphasis
on facial malformations and routine blood work, including complete blood
count, electrolytes, calcium, glucose, and kidney function test are
required. Hematologic or biochemical disturbances, especially hypocalcemia,
must be corrected prior to anesthesia. A complete medical history and
current medication, for example, antiseizure drugs with the potential for
drug interactions with anesthetic agents, must be documented. Anxiolysis is
particularly important with deafness and mental retardation.