Tryptophan supplementation and postoperative delirium--a randomized controlled trial.

OBJECTIVES

To determine whether the postoperative administration of tryptophan would be beneficial for elderly adults undergoing surgery who are at risk of developing postoperative delirium.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Denver Veterans Affairs Medical Center.

PARTICIPANTS

Individuals aged 60 and older undergoing major elective operations requiring a postoperative intensive care unit (ICU) admission (n = 325).

INTERVENTION: L-tryptophan, 1 g orally three times a day or placebo was started after surgery and continued for up to 3 days postoperatively.

MEASUREMENTS: Delirium and its motor subtypes were measured using the Confusion Assessment Method-Intensive Care Unit (CAM-ICU) and the Richmond Agitation and Sedation Scale. The primary outcome for between-group comparison was the incidence of excitatory (mixed and hyperactive) postoperative delirium. The secondary outcomes for comparison were the incidence and duration of overall postoperative delirium.

RESULTS

The overall incidence of postoperative delirium was 39% (95% confidence interval = 34-44%) (n = 116). Seventeen percent of participants in the tryptophan group and 9% in the placebo group had excitatory delirium (P = .18), and the duration of excitatory delirium was 3.3 ± 1.7 days for tryptophan and 3.1 ± 1.9 days for placebo (P = .74). Forty percent of participants in the tryptophan group and 37% in the placebo group had overall delirium (P = .60), and the duration of overall delirium was 2.9 ± 1.8 days for tryptophan and 2.4 ± 1.6 days for placebo (P = .17).

CONCLUSION

Postoperative tryptophan supplementation in older adults undergoing major elective operations requiring postoperative ICU admission did not reduce the incidence or duration of postoperative excitatory delirium or overall delirium.