Methods: Between April 2011 and November 2011, preoperative, intraoperative, and postoperative data of 400 patients (276 males, 124 females; mean age 59.7 years; range 19 to 91 years) who underwent open heart surgery were recorded. The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) was applied to the patients at 24 and 72 hours following surgery. The patients who were consulted by ICU physicians with a preliminary diagnosis of delirium were compared to the patients whose CAM-ICU results were positive.

Results: The incidences of delirium were 3.8% and 1.8% at 24 and 72 hours, respectively. There was a statistically significant difference between the clinical observations of the patients who were reported to have delirium and those who were diagnosed with delirium after the application of the CAM-ICU (p<0.001). We found that the clinicians insufficiently recognized hypoactive delirium at 24 and 72 hours following surgery (p<0.001). Age, the use of hearing aids and the presence of coronary artery disease during the preoperative stage, intraoperative and postoperative hematocrit levels, postoperative drainage volume, a re-do surgery, history of being bedridden and blood transfusions were predictive risk factors for delirium, as assessed at 24 hours (p<0.05). The risk factors at the 72 hours were preoperative age, intraoperative hematocrit level, and postoperative blood transfusion and the duration of mechanical ventilation in the preoperative, intraoperative and postoperative periods (p<0.05).

Conclusion: After open heart surgery, using an easy-to-apply scale, such as the CAM-ICU, may be useful for the early diagnosis and treatment of delirium.