On Kathy’s first postoperative day, she continued
to state that she was in severe pain despite the fact that
she continued to be quite sleepy and require supplemental
oxygen to maintain oxygen saturation rates at
an acceptable level. While helping Kathy bathe she
looked confused and said, ‘‘Stop hitting me’’ and ‘‘those
black things on the wall are looking at me.’’ She seemed
to be in a great deal of emotional distress. It was clear
that Kathy was having visual hallucinations indicative
of delirium, most likely as a result of her medication
regimen. I was not surprised that Kathy would experience
postoperative delirium, because she had several
risk factors for the development of confusion in the
postoperative period. One of her medications, ketamine,
is known to have mind-altering adverse effects,
such as visual hallucination. Kathy was receiving 0.3
mg/kg/h ketamine and was on 1 mg/mL Diludid PCA
with settings of 0.6 mg every 7 minutes, no lockout,
and no continuous dosing.