MONTREALDelirium in patients with advanced cancer appeared to be
associated with changes in the circadian distribution of analgesia for
breakthrough pain and may be due to a reversal of the normal circadian rhythm
in these patients, reported Bruno Gagnon, MD, of McGill University and Montreal
The study was conducted as part of a prospective study of delirium in
advanced cancer patients in the acute palliative care unit at Grey Nuns
Community Hospital & Health Centre, Edmonton, Alberta. The patient charts
were retrospectively analyzed for breakthrough analgesia use; however, the
patients, nurses, and physicians were blinded to the fact that the review would
be carried out.
Breakthrough analgesia use was divided into three time periods: 11:30 pm to
7:30 am (night); 7:30 am to 3:30 pm (day), and 3:30 pm to 11:30 pm (evening),
corresponding to the length of the nursing shifts.
The study included 104 eligible patients categorized into three groups based
on delirium status: Group 1 (n = 33) had no delirium on admission or during
their hospital stay; group 2 (n = 22) had terminal or nonreversible delirium;
and group 3 (n = 49) had a changing delirium status (at least one period of
delirium in addition to one or more delirium-free periods).
A total of 1,677 patient admission days were analyzed for circadian
distribution of breakthrough analgesia doses: 1,254 days without delirium and
423 days with delirium. The researchers found that the circadian distribution
of breakthrough analgesia doses differed significantly from a random
distribution in both patients with and without delirium (J Pain Symptom Manage
During delirium-free days, patients required more breakthrough analgesia
doses during the daytime, compared with a random distribution, whereas when
delirium was present, more breakthrough analgesia was used during the evening
and at night (see Table).
Similarly, the group 2 patients (terminal delirium) received more
breakthrough analgesic doses during the evening, compared with the group 1 (no
delirium) patients. Furthermore, among the group 3 patients (changing delirium
status), the highest breakthrough analgesia use was during the evening when
delirium was present and during the day when delirium was absent.