A Patient Is Admitted with Coronary Artery Disease and Is

A patient is admitted with coronary artery disease and is scheduled for coronary artery bypass grafting (CABG) . According to the clinical pathway the patient should be extubated and discharged from critical care the day after surgery. During surgery the patient's oxygen saturation decreased drastically as a result of chronic tobacco abuse. Subsequently, the patient remained on the ventilator an additional 2 days postoperatively. According to the clinical practice guideline for CABG, this situation represents a:

A) patient outcome.
B) variance.
C) goal.
D) standard.