The changing face of acute pain services.

BACKGROUND AND AIMS: Acute Pain Services have been implemented initially to treat inadequate postoperative pain. This study was undertaken to prospectively review the current challenges of the APS team in an academic hospital assessing the effects of its activity on both surgical and medical pain intensity. It also define the characteristics of the patients and the risk factors influencing the multiple visits from the APS team.

METHOD: This prospective cohort study was conducted at Uppsala University Hospital (a Swedish tertiary and quaternary care hospital) during one year. All the patients referred to the APS team were enrolled. A standardized data collection template of demographic data, medical history, pain diagnosis, associated diseases, duration of treatment, number of visits by the APS team and type of treatment was employed. The primary outcomes were pain scores before, after treatment and the number of follow-ups. The patients were visited by APS at regular intervals and divided by the number of visits by APS team into several groups: group 1 (one visit and up to 2 follow ups); group 2 (3 to 4 follow-ups); group 3 (5 to 9 follow-ups); group 4 (10 to 19 follow-ups); group 5 (>20 followups). The difference between groups were analyzed with ordinal logistic regression analyses.

RESULTS: Patients (n=730) (mean age 56±4, female 58%, men 42%) were distributed by service to medical (41%) and surgical (58%). Of these, 48% of patients reported a pain score of moderate to severe pain and 27% reported severe pain on the first assessment. On the last examination before discharge, they reported 25-30% less pain (P=0.002). The median NRS (numerical rating scores) decreased significantly from 9.6 (95% confidence interval, 8.7-9.9) to 6.3 (6.1-7.4) for the severe pain (P<0.0001), from 3.8 (3.2-4.3) to 2.4 (1.8-2.9) for the moderate pain. The odds ratio for frequent follow-ups of the patients between 18 and 85 years (n=609) was 2.33 (95% CI: 1.35-4.02) if the patient had a history of chronic neuropathic pain, 1.80(1.25-2.60) in case the patient had a history of chronic nociceptive pain, 2.06(1.30-3.26) if he had mental diseases, and 3.35(2.21-5.08) if he had opioid dependency at the time of consultation from APS. Strong predictors of frequent visits included female gender (P=0.04).

CONCLUSIONS: Beside the benefits of APS in reducing pain intensity, this study demonstrates that the focus of APS has been shifted from the traditional treatment of acute surgical pain to the clinical challenges of treating hospitalized patients with a high comorbidity of psychiatric diseases, opioid dependency and chronic pain.

IMPLICATIONS: The concept of an APS will ultimately be redefined according to the new clinical variables. In the light of the increasing number of patients with complex pain states and chronic pain, opioid dependency and psychiatric comorbidities it is mandatory that the interdisciplinary APS team should include other specialties besides the "classical interdisciplinary APS team", as psychiatry, psychology, rehabilitation and physiotherapy with experience in treating chronic pain patients.