Independent association between preoperative cognitive status and discharge location after cardiac surgery

Abstract

Background: Among cardiac surgery patients, those with impaired cognitive status before surgery may have longer postoperative stays than do patients with normal status and may require additional care upon discharge.

Objectives: To determine if preoperative scores on a screening measure for cognitive status (the Clock-in-the-Box), were associated with postoperative length of stay and discharge to a location other than home in patients who had cardiac surgery.

Methods: A total of 181 consecutive patients scheduled for cardiac surgery at a single site were administered the Clock-in-the-Box as part of the preoperative evaluation. Scores on the Clock-in-the-Box tool, demographic and operative information, postoperative length of stay, and discharge location were collected retrospectively from medical records.

Results: The mean age of the patients was 68.1 years (SD, 0.7), and 99% were men. Mean postoperative length of stay was 10.5 days (SD, 8.2), and 35 patients (19%) were discharged to a facility. Scores on the Clock-in-the-Box assessment were not associated with postoperative length of stay. Increasing age, living alone before surgery, and duration of cardiopulmonary bypass were associated with discharge to a facility and were used as covariates in adjusted analyses. After adjustment, better preoperative cognitive status reduced the risk of being discharged to a facility (adjusted relative risk, 0.93; 95% confidence interval, 0.89-0.98) after cardiac surgery.

Conclusions: Cognitive screening before cardiac surgery can identify patients with impaired cognitive status who are less likely than patients with normal cognitive status to return home after cardiac surgery.

Figure 1. Clock Drawings and Clock-in-the-Box (CIB) Score

Panel A depicts a drawing with a CIB Score = 8. In Panel B, the time is set incorrectly and the clock was drawn in the wrong box (not shown). The clock in Panel C shows disorganization with impaired number spacing, circle size, hand origin, and wrong box (not shown). Panel D received credit for identifying the object as a clock and the correct box (not shown).

Figure 2. Clock-in-the-Box Performance and Postoperative Outcomes

Panel A depicts the mean postoperative length of stay with CIB score. While mean length of stay declines with improving clock score, the trend was not significant (p=.30). Panel B depicts the percentage of patients returning home with Clock-in-the-Box performance. Participants with better preoperative Clock-in-the-Box performance were more likely to be discharged home (p=.04).