Individual risk profiles for postoperative delirium after joint replacement surgery.

BACKGROUND: Delirium occurs in nearly half of older patients after joint replacement surgery. However, risk profiles for developing delirium have not been established. OBJECTIVE: We sought to identify risk profiles for delirium in patients following joint replacement surgery. METHOD: Based on data from a randomized, double-blind, placebo-controlled trial of olanzapine (10 mg) as delirium prophylaxis in 400 patients (67-81 years old) undergoing hip or knee replacement surgery, we performed a signal detection analysis to develop risk profiles for postsurgical delirium (using baseline patient characteristics, iatrogenic factors, and physiologic response parameters). RESULTS: Olanzapine reduced the incidence of delirium by 63% relative to placebo. Among patients receiving placebo, those with an ASA class = 3 and age ≥ 74 years had a 64% risk of delirium. Those with ASA class < 3 still had a 67% risk of delirium if postoperative oxygen saturation was < 95%. Patients who received olanzapine had an 83% risk of developing delirium if they received ≥ 42.5 mg equivalents of intra-operative morphine, were ≥ 74 years old, and had a mean arterial pressure (MAP) < 90 mm Hg at the presurgical screening visit. Patients with the lowest risk (6%) of developing delirium received olanzapine had a hematocrit ≥ 28%, and a presurgical MAP ≥ 90. CONCLUSION: Although use of prophylactic olanzapine reduced the incidence of delirium, subsets of patients remained likely to develop delirium. The risk of developing delirium may be reduced through prophylactic dispensation of olanzapine, maintaining optimal perfusion and oxygenation, and limiting intra-operative opioids.

Administration of olanzapine to prevent postoperative delirium in elderly joint-replacement patients: a randomized, controlled trial.

BACKGROUND: Delirium is a serious postoperative condition for which few pharmacologic prevention trials have been conducted. OBJECTIVE: The authors tested the efficacy of perioperative olanzapine administration to prevent postoperative delirium in elderly patients after joint-replacement surgery. METHOD: The authors conducted a randomized, double-blind, placebo-controlled, prophylaxis trial at an orthopedic teaching hospital, enrolling 495 elderly patients age ≥65 years, who were undergoing elective knee- or hip-replacement surgery; 400 patients received either 5 mg of orally-disintegrating olanzapine or placebo just before and after surgery. The primary efficacy outcome was the incidence of (DSM-III-R) delirium. RESULTS: The incidence of delirium was significantly lower in the olanzapine group than in the placebo group; this held true for both knee- and hip-replacement surgery. However, delirium lasted longer and was more severe in the olanzapine group. Advanced age, a high level of medical comorbidity, an abnormal albumin level, and having knee-replacement surgery were independent risk factors for postoperative delirium (Clinicaltrials.gov Identifier: NCT000699946). CONCLUSION: Administration of 10 mg of oral olanzapine perioperatively, versus placebo, was associated with a significantly lower incidence of delirium. These findings suggest that olanzapine prophylaxis of postoperative delirium may be an effective strategy.