Motor subtypes of postoperative delirium in older adults

Abstract

Hypothesis: Increased knowledge about motor subtypes of delirium may aid clinicians in the management of postoperative geriatric patients.

Design: Prospective cohort study defining preoperative risk factors, outcomes, and adverse events related to motor subtypes of postoperative delirium.

Setting: Referral medical center.

Patients: Persons 50 years and older with planned postoperative intensive care unit (ICU) admission following an elective operation were recruited.

Main outcome measures: Before surgery, a standardized frailty assessment was performed. After surgery, delirium and its motor subtypes were measured using the validated tools of the Confusion Assessment Method-ICU and the Richmond Agitation-Sedation Scale. Statistical analysis included the univariate t and χ(2) tests and analysis of variance with post hoc analysis.

Results: Delirium occurred in 43.0% (74 of 172) of patients, representing 67.6% (50 of 74) hypoactive, 31.1% (23 of 74) mixed, and 1.4% (1 of 74) hyperactive motor subtypes. Compared with those having mixed delirium, patients having hypoactive delirium were older (mean [SD] age, 71 [9] vs 65 [9] years) and more anemic (mean [SD] hematocrit, 36% [8%] vs 41% [6%]) (P = .002 for both). Patients with hypoactive delirium had higher 6-month mortality (32.0% [16 of 50] vs 8.7% [2 of 23], P = .04). Delirium-related adverse events occurred in 24.3% (18 of 74) of patients with delirium; inadvertent tube or line removals occurred more frequently in the mixed group (P = .006), and sacral skin breakdown was more common in the hypoactive group (P = .002).

Conclusions: Motor subtypes of delirium alert clinicians to differing prognosis and adverse event profiles in postoperative geriatric patients. Hypoactive delirium is the most common motor subtype and is associated with worse prognosis (6-month mortality, 1 in 3 patients). Knowledge of differing adverse event profiles can modify clinicians' management of older patients with postoperative delirium.

Figure 1. Study Enrollment Summary

Ineligible 44 subjects included: operations on the brain (39), hearing impaired (3) and vision impaired (2).

Figure 2. The Incidence of the Motor Subtypes of Post-Operative Delirium