The changing face of acute pain services

Adriana Miclescu; Stephen Butler; Rolf Karlsten

doi:10.1016/j.sjpain.2017.04.072

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The changing face of acute pain services

Adriana Miclescu , Stephen Butler and Rolf Karlsten

Published/Copyright: July 1, 2017

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From the journal Scandinavian Journal of Pain Volume 16 Issue 1

Abstract

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.

Keywords: Acute pains services; Predictors of uncontrolled pain; Complications of pain treatment

1 Introduction

Despite of major advances in analgesic medication, delivery techniques and the introduction of new pain treatment protocols, optimal pain treatment remains elusive and is the most common concern in more than one half of the hospitalized patients [1].There is increasing recognition that failure to provide good postoperative pain relief causes unnecessary discomfort, longer hospital stays, increased expense, and less than optimal clinical outcomes in hospitalized patients [2, 3]. There is no doubt that effective pain relief would result in shorter clinical recovery, shorter hospital stays and improved quality of life [4].

After the publication by Brian Ready in 1988 of a description of an anesthesiology-based acute pain service [5] the number of hospitals offering acute pain services (APS) increased worldwide. Although most hospitals implemented acute pain teams because of the detrimental effects that inadequate postoperative pain management can have on patients and also to treat “patients with chronic pain and unmanageable pain states” [6] the role of this service has been shifted today in response to new clinical challenges. The current focus of the APS has been changed from managing acute postoperative pain to a more comprehensive service due to an increasing number of referrals for hospitalized patients with untreated and undertreated pain who have concomitant disease, complex medication and histories, comorbid conditions such as opioid dependency, chronic non cancer pain, drug addiction, drug abuse, psychiatric and psychological disturbances. It is essential therefore to understand how patient characteristics such as age, gender, type of pain and coexisting comorbidities affect the multiple follow-ups by APS team aimed to treat difficult to control pain. Because of the new challenges there is a need in the acute pain team not only of an anaesthesiologist but also of qualified personnel from other specialties. This study was undertaken to prospectively review the current challenges of the APS team to define the characteristics of the patients with pain states requiring multiple visits by the APS team.

Our aims were twofold: first, to describe the risk factors influencing the multiple visits from the APS team; second, to analyze the choice of the treatment and the effects of the treatment instituted by the APS.

2 Methods

The pharmacological protocols for pain control of the medical patients were developed in Uppsala University Hospital by a multidisciplinary pain committee (pharmacists, anesthesiologists, general practitioners, pain specialists) and postoperative pain protocols by anesthesiologists, pain specialists and registered pain nurses. Pharmacological pain therapy is followed up on a daily basis by physicians. Advanced postoperative pain therapy such as patient-controlled analgesia (PCA), continuous epidural analgesia (EDA), continuous spinal analgesia (SPA) and peripheral nerve blocks by infusion (PNB) are followed up by a registered anaesthesiologist nurse for the first few days after the treatment was instituted or by the ward nurses who have specialized PCA, EDA-pump device training. The patients are referred to the APS in the case of pain with intensity over 6 NRS despite the treatment instituted by the ward, for the treatment of pain in addicted patients. Usually the reason for the requested help from the APS team is that the patients have an NRS more than 6, and do not respond to the usual therapy instituted by the physicians, for recommendation of perioperative pain relief in patients with high doses of opioids (more than 200 mg morphine equivalents) or opioid tolerant patients.

The Ethical Committee of Uppsala University approved the study protocol (reference number 2016/416). A standardized data collection template (both electronic and paper) was employed for the patients referred to the APS team during one year (August 2015-July 2016). The template included demographic data (age, sex), history, pain diagnosis, associated diseases, duration of treatment and number of visits by the APS team, type of treatment and side effects. Patient data were collected using both chart review and personal reports of the patients. The data system used was Microsoft Excel® database and the electronic patient journal used within the hospital (Cosmic®). The patients were visited by the APS at regular intervals based on the individual needs. The team consisted of a pain specialist physician and a nurse pain specialist. The APS team physician included 2 anesthesiologists, 1 general practitioner, all specialized in pain management and 2 advanced practice pain nurses. Each patient was seen and followed when possible by the same pain clinician and nurse. Data collection occurred over one year.

From the patient’s journal we obtained documentation which included associated diseases, previous laboratory tests, X-rays, MRI, neurophysiological tests and type of surgical interventions. At the time of the APS team visit a comprehensive history was taken. The medical patients underwent a detailed neuromuscular examination and a targeted physical examination.

A diagnosis based on the type of pain was made as follows: acute and chronic nociceptive and neuropathic pain, their subtypes (somatic musculoskeletal and visceral pain, peripheral and central neuropathic pain) and pain conditions as acute nociceptive postoperative pain and cancer related pain. Furthermore, addiction, opioid dependency and psychiatric comorbidities were recorded. The team followed up the patients until pain intensity was improved as judged by the patients and by the ward. Discontinuation of APS team visits occurred also when the patients were transferred to another hospital or discharged home.

2.1 Pain prevalence and intensity

Pain documentation was recorded on an 11-point pain intensity numerical rating scale (NRS where 0 = no pain at all, to 10 = worst imaginable pain) before and after the treatment. The lowest pain score, highest pain scores the previous day and present pain were measured.

2.2 Analgesia

Data on the pre-consultation analgesia given were obtained from the computerized patient journal. Patients were treated with systemic analgesics administrated orally or intravenously, given regularly, intermittently or via PCA, with analgesia adjuvants, regional blocks, and epidural or intrathecal analgesia. To optimize pain management and reduce side effects, multimodal analgesia was used and the pain treatment adjusted to the patients’ individual analgesia requirements. Pain improvement was measured by a decrease of pain scores, and/or resolution of side effects.

2.3 Groups

After data collection, the patients were divided into groups according to the number of visits required by the APS: 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 (more than 20 follow-ups).

3 Statistics

Non-parametric statistical methods were performed by the author with GraphPad PRISM 5.0 (GraphPad Software, La Jolla, San Diego, CA, www.graphpad.com 5.0). Data are presented as mean and SD or median with interquartile range to give better characteristics of data distribution. The level of significance was set at a P value of .05 or less. Normally distributed data were analyzed using Student’s t-test, skewed data were compared using the Mann–Whitney test. Binomially distributed data were analyzed using the X² test and presented as frequency distributions with absolute numbers and relative distribution in per cent.

Partial proportional odds models were used to investigate the association between the number of follow-ups (1–2, 3–4, 5–9, 10–19 and >20) and potential predictors (age, sex, type of pain, mental diseases, opioid addiction and abuse). A multivariable model using backward selection (P ≤ 0.10 to stay) were estimated and odds ratios (OR) with 95% confidence interval were reported.

4 Results

4.1 Age and gender

A total of 730 patients were included in the study. The age range of the patients varied from 2 years old to 103, with a mean age of 56±2 years. The adults aged 50 to 64 years had the highest need for the presence of APS (24.2%). Females were represented more (58.6%) than males (41.4%).

4.2 Characteristics of the patients

Overall, 41% (n = 300) were nonsurgical (medical) patients and 59% (n = 430) were surgical patients (Table 1). The ratio of surgical patients/to nonsurgical patients was 1.4. The majority of the patients referred to the APS came from the following specialties: orthopaedics (20.0%), oncology (10.0%), abdominal surgery (7.8%), neurosurgery (5.0%) and gynaecology (4.9%).

Table 1

Identification of disease-related groups.

DRG	Surgical speciality	Patients (N)	Percent	DRG	Medical specialty	Patients (N)	Percent
1	Orthopaedics	154	21%	13	Oncology	75	10.3%
2	Abdominal surgery	59	8.0%	14	Reumatology	35	4.8%
3	Neurosurgery	37	5.0%		Infectious disease	26	3.5%
4	Gynaecology	36	4.9%	15	Cardiology	20	2.7%
5	Vascular surgery	25	3.4%		Nephrology	24	3.3%
6	Plastic surgery	21	2.8%	16	Neurology	23	3.1%
7	Thoracic surgery	21	2.8%	17	Internal medicineLung medicine	21 19	2.8%2.6%
8	Surgical intensive care	20	2.7%	18	Paediatric	16	2.2%
9	ENT surgery	17	2.3%	19	Geriatrics	15	2.0%
10	Urology	16	2.2%	20	Psychiatry	12	1.6%
11	Burn unit	15	2.0%	21	Medical intensive care	8	1.1%
12	Postoperative ward	9	1.2%	22	Emergency room-medical	5	0.6%
	Surgical	430	59%		Medical	300	41%

4.3 Number of patients and follow-ups in different groups

The majority of the patients (62%) required the presence of the APS just once or twice (Group 1 with N = 450 patients). Group 2 consisted of 114 patients (15%), Group 3 consisted of 107 patients (15%), Group 4 consisted of 45 (6%) and there were 14 patients in Group 5 (2%). The mean number of visits for all patients was (mean±SD) 2.5±2 visits.

4.4 Pain levels

The results revealed a significant decrease in mean values for pain measured by NRS in all groups (Fig. 1). Overall, 48% of the total number of patients reported a pain score of moderate to severe and 27% reported severe pain on the first assessment. On the last examination before discharge from the APS team, they reported 25–30% less pain (P = 0.002). The median NRS 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 < 0.001), from 3.8 (3.2–4.3) to 2.4 (1.8–2.9) for the mild pain for all the patients.

Fig. 1

Worst pain (NRS) before (black bars) and after treatment (white bars) and best pain (NRS) before (black bars) and after treatment (white bars) in all the five groups of the patients.

4.5 Pain treatment

The most commonly used pain medication was oxycodone (34%), followed by morphine (24%), fentanyl 14%, ketobemidone (12%), buprenorphine (both patches and sublingually) (12%), methadone (3%), other opioids such as tramadol, tapentadol and codeine (1%) or non-opioids in the treatment. In 7% of the cancer patients with severe pain or non-cancer patients with high opioid consumption, ketamine was used as an adjuvant to the pain treatment. As indicated by this study, PCA is the most commonly used advanced analgesic technique (11% of all patients). Epidural analgesia was used in 9% of the patients, peripheral regional blocks in 4% patients and continuous spinal analgesia in 1%.

4.6 Subgroup analysis

Despite no differences in ASA physical status, an increased prevalence of several comorbidities (concomitant psychiatric disease, opioid dependency, chronic pain and mixed types of pain) was observed in the patients who required with more than 5 visits by the APS (Table 2).

Table 2

Subgroup analysis.

	N	Medical	Acute Pain	Acute Surgery	Elective Surgery	Peripheral Neuropathic Pain	Central Neuropathic Pain	Muskulo skeletal	Cancer Pain	Visceral Pain	Chronic Nociceptive Pain	Chronic Neuropathic Pain	No dx	Psychiatric dg	Abuse	Opioid dependency	ASA >2
1	450	211(47%)	285(63%)	65(14%)	170(38%)	69(15%)	28(%)	58(13%)	75(17%)	66(15%)	166(37%)	57(13%)	15(3%)	48(11%)	26(6%)	60(13%)	150(33%)
2	114	48(42%)	100(88%)	30(26%)	32(28%)	21(18%)	14(2%)	17(15%)	29(25%)	31(27%)	48(42%)	16(14%)	6(5%)	22(19%)	8(7%)	20(18%)	42(37%)
3	107	53(50%)	74(70%)	28(26%)	25(23%)	16(15%)	11(10%)	20(19%)	23(21%)	20(19%)	39(36%)	21(20%)	2(2%)	23(21%)	12(11%)	32(30%)	31(29%)
4	45	22(49%)	30(67%)	7(16%)	10(22%)	9(20%)	6(13%)	12(27%)	6(13%)	9(20%)	28(62%)	14(31%)	2(4%)	18(40%)	4(9%)	25(56%)	12(27%)
5	14	5(36%)	10(71%)	5(36%)	1(7%)	2(14%)	2(14%)	1(7%)	5(36%)	9(64%)	12(86%)	5(36%)	1(7%)	6(43%)	2(14%)	14(100%)	4(29%)

Group 1

In this group (including those referred for preoperative assessment, n = 20, patients discharged same day to home or to another hospital, n = 30) 284 patients (mean age 56±1 years; 34% women and 27% men) required only one visit of APS. The patients (n = 20) for preoperative assessment were those whose postoperative pain control was considered to be challenging (fifteen orthopaedic patients, four abdominal surgical patients, and one neurosurgical patient) due to chronic opioid use, substance abuse and for previous severe pain after operation, were referred to the APS for preoperative suggestions for postoperative pain control and postoperative follow-up.

The remaining 136 patients required 2 visits by the team. A surgical diagnosis required the presence of the APS team in 63% of the patients in group 1 (abdominal, vascular, urological in 31% of the patients, 22% orthopaedic diagnosis, 6% plastic and ENT surgery and 4.2% neurosurgery). A comorbid medical diagnosis was present in 47% of the patients. The prevalence of psychiatric disorders (11%), opioid dependency (13%) and the presence of chronic pain (49.5%) were lowest in this group in comparison with the other groups (Table 2). Depression accompanied physical symptoms in 79% of the 48 patients with psychiatric disorders from group 1 (representing 8.4% of the patients in group 1) followed by neuropsychiatric diagnoses in 20% of the patients (2.2% of the patients in group 1).

Group 2

In this group, 114 patients (mean age 55±1 years; women 74%, men 30%) required either 3 (69% of the patients) or 4 visits (31% of the patients) by the APS team. A surgical diagnosis was present in 58% of the patients in this group (17% abdominal, urological, vascular), 18% orthopaedic surgery. Psychiatric disease was present in 19% of the patients and depression was the main diagnosis.

Group 3

This group consisted of 104 patients (mean age 47±2 years; women 64% and men 36%) requiring between 5 and 9 visits by APS team. A surgical diagnosis was present in 70% of the patients in this group (30% abdominal, urological, vascular), 21.5% orthopaedic surgery. A psychiatric disease diagnosis was made in 21% of the patients and depression was the main diagnosis.

Group 4

In this group, 45 patients required between 10 and 19 visits by the APS team (mean age of 46±2; 60% women and 40% men). A surgical diagnosis was present in 49% of the patients (37% general surgery, 15% orthopaedic surgery). Cancer associated pain required the presence of the APS team in 6.6% of the patients. A psychiatric disease diagnosis was present in 40% of the patients and opioid addiction in 56% in this group.

Group 5

In this group of 14 patients (mean age of 44±4 years; women 65%, men 35%) all the patients had opioid dependency and the highest percent of psychiatric diseases of all the groups (43%). The diagnoses were endometriosis (14%), postoperative pain after orthopaedic operations (21%), reoperations (35%), cancer related pain (35%).

4.7 Odds ratio (OR) for frequent follow-ups

Partial proportional odds models were used to investigate the predictors for frequent follow-ups (preoperative patients n = 20, and patients discharged the same day from the hospital n = 30 were excluded). There was a significant correlation between number of visits and acute pain (OR=1.65, P = 0.002), but acute pain did not fulfil the assumption of proportional odds and therefore we used a partial proportional odds model allowing acute pain to have different effects on different levels of APS activity (number of follow-ups).

The association of age, sex, ASA score, type of pain, mental diseases, opioid addiction and abuse with the number of follow-ups studied with ordinal logistic regression analyses is represented in Table 3. The odds ratio for frequent follow-ups of the patients between 18 and 85 years (n = 609) were 3.35(95% CI: 2.21–5.08) if the patient had opioid dependency at the time of consultation from APS, 2.33 (95% CI:1.35–4.02) if the patient had a history of chronic neuropathic pain, 2.06 (95% CI:1.30–3.26) if the patient had a psychiatric diagnose, 2.05 (95% CI:1.29–3.24) if the pain diagnose was cancer associated pain, musculoskeletal pain with OR of 2.05 (95% CI:1.29–3.24) and OR 2.04 (95% CI: 1.20–3.49) in case of acute surgery. Other predictors were a pain diagnose of central neuropathic pain 1.96 (95% CI: 1.04–3.69), a history of chronic nociceptive pain 1.80 OR (95% CI: 1.25–2.60), visceral pain 1.70 (95% CI:1.09–2.65) female gender 1.45 (95% CI 1.01–2.09). The number of follow ups depended also on the age of the patients, when we considered all the patients in all ages without missing observations (n = 730) and not just between 18 and 85 years of age (P = 0.011). Opioid abuse, peripheral neuropathic pain, elective surgery, ASA score over 2 was not found as consistent predictors for frequent follow-ups.

Table 3

Partial proportionaloddsmodel.

Variable: Yes vs No outcome	Outcome	N = 676	OR(95%CI)	18≤age<85 n = 609	OR(95%CI)
		Crude OR(95%CI)		Crude OR(95%CI)
Acute pain	Groups
Yes vs No	2–5 vs 1	1.90(1.34–2.71) P < 0.001	2.38(1.47–3.85) P < 0.001	1.85(1.28–2.67) P = 0.001	2.31(1.40–3.81) P = 0.001
Yes vs No	3–5 vs 1–2	0.99(0.67–1.47) P = 0.967	1.04(0.63–1.73) P = 0.879	0.98(0.65–1.47) P = 0.908	1.01(0.60–1.72) P = 0.962
Yes vs No	4–5 vs 1–3	1.06(0.55–2.03) P = 0.866	1.05(0.50–2.18) P = 0.906	1.02(0.53–1.97) P = 0.957	0.97(0.46–2.05) P = 0.938
Yes vs No	5 vs 1–4	1.11(0.28–4.34) P = 0.878	0.97(0.24–4.02) P = 0.971	1.11(0.28–4.34) P = 0.882	0.92(0.22–3.83) P = 0.906
Opioid dependency		4.20(2.92–6.04) P < 0.001	3.43(2.28–5.15) P < 0.001	4.10(2.83–5.95) P < 0.001	3.35(2.21–5.08) P < 0.001
Chronic neuropathic pain		1.80(1.21–2.68) P = 0.004	1.99(1.18–3.36) P = 0.010	2.12(1.39–3.24) P < 0.001	2.33(1.35–4.02) P = 0.002
Psychiatric dg		2.71(1.82–4.03) P < 0.001	2.16(1.39–3.35) P < 0.001	2.57(1.71–3.88) P < 0.001	2.06(1.30–3.26) P = 0.002
Cancer associated pain		1.57(1.08–2.28) P = 0.018	2.25(1.45–3.50) P < 0.001	1.42(0.96–2.09) P = 0.076	2.05(1.29–3.24) P = 0.002
Acute surgery		1.81(1.23–2.68) P = 0.003	2.06(1.24–3.43) P = 0.005	1.81(1.20–2.71) P = 0.004	2.04(1.20–3.49) P = 0.009
Central neuropathic pain		1.93(1.15–3.23) P = 0.013	1.88(1.02–3.45) P = 0.042	2.14(1.24–3.66) P = 0.006	1.96(1.04–3.69) P = 0.037
Chronic nociceptive pain		1.53(1.12–2.08) P = 0.007	1.74(1.22–2.49) P = 0.002	1.67(1.21–2.30) P = 0.002	1.80(1.25–2.60) P = 0.002
Musculoskeletal pain		1.51(1.00–2.26) P = 0.048	1.76(1.11–2.79) P = 0.016	1.44(0.95–2.20) P = 0.087	1.71(1.06–2.75) P = 0.028
Visceral pain		1.79(1.23–2.61) P = 0.003	1.65(1.08–2.53) P = 0.022	1.74(1.18–2.57) P = 0.005	1.70(1.09–2.65) P = 0.019
Female		1.42(1.03–1.94) P = 0.031	1.39(0.98–1.97) P = 0.061	1.46(1.05–2.04) P = 0.024	1.45(1.01–2.09) P = 0.042
Peripheral neuropathic pain		1.12(0.74–1.70) P = 0.595	1.11(0.68–1.81) P = 0.689	1.16(0.74–1.81) P = 0.526	1.02(0.60–1.74) P = 0.938
Age per 10 year		0.88(0.81–0.95) P = 0.001	0.89(0.82–0.97) P = 0.011	0.89(0.81–0.97) P = 0.012	0.90(0.81–1.00) P = 0.059
Elective surgery		0.73(0.51–1.05) P = 0.087	0.77(0.48–1.22) P = 0.257	0.69(0.47–1.00) P = 0.052	0.75(0.46–1.22) P = 0.247
No dx		1.45(0.64–3.28) P = 0.369		1.37(0.61–3.10) P = 0.450
Opioid abuse		1.40(0.79–2.48) P = 0.251		1.31(0.74–2.33) P = 0.353
ASA >2		0.83(0.60–1.16) P = 0.280		0.89(0.63–1.26) P = 0.515

5 Discussion

The aim of this prospective study was to investigate the factors associated with difficult to control pain as measured by frequent visits by the APS team in an academic hospital. The paper advocates the use of a prediction model to develop a more consistent explanatory model. To summarize, we found that frequent visits were strongly predicted by clinical variables such as psychiatric comorbidity, opioid dependency and chronic pain. The American Society of Anesthesiologists Physical Status (ASA) score was not a predictor for frequent visits by APS team. To predict comorbidity, we used the ASA score in both surgical and nonoperative patients, based on the agreement relationship between two comorbidity classification systems for surgical and nonsurgical patients (ASA score and the Charlson Comorbidity Index) [7].

5.1 Characteristics of the patients

This paper demonstrates also the tendency of the APS to be involved in treating more patients with medically related pain rather than surgically. In comparison with the results collected from seven hospitals in UK, where the proportion of nonsurgical patients seen by APS was 17% (range 3–33%) in 2010, and 14% (range 4–40%) in 2011 by collection of data from thirteen hospitals [8], the tendency in our hospital is to have higher numbers of patients coming from medical specialties (41%) which is more than double the number of medical patients consulted by the APS in the UK. The variation might also be due to the level of hospital reporting the data.

5.2 Pain levels

The values of clinically relevant pain categories (maximal pain and pain on movement) were significantly reduced by 25–30% from baseline in our cohort. Moderate to severe pain was present in one third of surgical patients and 1 in 6 medical patients [9]. The pain treatment instituted by the APS led to reductions in both medical and postoperative pain. Several observational studies have indicated previously that an APS reduces perioperative pain and also the risk of complications although treatment components of the acute pain services varied across the studies [10, 11, 12].

5.3 Gender

Female gender was more represented among the patients seen by the APS team and was also associated with more frequent visits in order to reduce pain. It is known from previous studies that the prevalence of chronic pain is increasing in the population and women report chronic pain more frequently [13].

5.4 Subgroup analysis

Unfortunately, there are very few studies to discuss the association between psychiatric symptoms and pain comorbidity [14]. It was demonstrated here that a history and diagnosis of mental disease increased from 11% in group 1 to 43% in group 5, had strong associations with pain and required multiple follow-ups by APS team. It is well known that both pain treatment outcomes and health costs are strongly influenced by psychological factors including psychiatric comorbidity [15]. Coexistence not only of chronic pain, but also postoperative pain and psychiatric disease leads to poorer outcome and increased risk of opioid abuse [16, 17, 18, 19]. Common psychiatric comorbidities in chronic pain patients with prevalence rates exceeding prevalence rates in the general population are affective disorders, anxiety disorders and substance abuse/dependency disorders [20, 21, 22]. Concurrent depression was the main diagnosis (80%) among the mental health diagnoses attributed to the patients followed by the APS team. The prevalence rates for depression among all the patients in the study was 12% which is the same as the prevalence rates for depression seen in gynaecological patients with pelvic pain undergoing laparoscopy [23]. The prevalence of depression in our study was lower than in other surgical patients as those undergoing disc surgery (21.5% to 49.3% before and between 4.1% to 79.6% after disc surgery) [21] or the patients in pain clinics (mean prevalence 52%, range 1.5–100%), psychiatric clinics (mean prevalence 38%, range between 6% and 64%) and in orthopaedic clinics and rheumatology clinics (mean prevalence 56%, range 21% and 89%) [16]. Probably the prevalence of mental diseases in our study would have been higher if we had a clinical assessment using standard interviews. In treating acute pain in this hospital, mental illness was often ignored both in the assessment and, subsequently, in the treatment. Those medical and surgical inpatients with associated mental disease presented special challenges for pain specialists who are often frustrated in their attempts to treat pain resulting in multiple follow-ups by APS and difficult to treat pain.

The proportion of patients with chronic pain treated with opioids and the proportion of opioid-tolerant patients requiring acute pain management have increased, often presenting greater challenges for APS team to treat than when treating opioid-naive patients [24]. The patients with chronic pain receiving chronic opioid administration increased dramatically among the groups of patients who required multiple follow-ups by the APS team. Previous studies have shown that opioid addicted patients have opioid resistance, lower pain thresholds [25] and higher pain sensitivity [26] with consequent inadequate acute pain control that could explained the multiple follow-ups by APS team.

5.5 Pain treatment

Opioid analgesia was demonstrated in this study to be the primary pharmacologic intervention for managing pain in hospitalized patients. Opioids used included oxycodone, morphine, fentanyl, l-methadone, and buprenorphine. Opioid rotation was the most frequent method adopted by the APS team in 32–38% of the patients. The indications for opioid rotation were insufficient analgesia or intolerable side effects. Although the management of pain in the hospital setting can be a difficult task to accomplish, the APS provided a multimodal approach for the prevention and treatment of acute pain with the goal of improving patient’s pain as evidenced by the decrease of NRS score.

To our knowledge, this is the first study to demonstrate the changing face of APS and the need for a new view on the organization of an APS in light of the increasing number of patients with chronic pain and comorbidities who need acute pain treatment in the hospital. Other authors [27] were investigating appropriate quality parameters for how to organize an APS and also to start an international pain registry for postoperative pain. This would certainly help monitor perioperative pain, uncover the populations at risk and would provide early treatment strategies.

In the future, treating acute painful physical symptoms that are frequently associated with mood disorders, the psychiatric component of treatment needs to be given full consideration because the severity of pain correlates with psychologic factors. 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” which previously included anaesthesiologist, acute pain nurses (APN), pharmacists, surgeons, and designated ward nurses [28]. These “new” specialties are psychiatry, psychology, rehabilitation and physiotherapy with experience in treating chronic pain patients. These specialists would provide the possibility of following the patients with “difficult” postoperative pain treatment after discharge from the hospital in the translational pain services [29, 30, 31].

6 Limitation of the study

The present data reflect the current pain service in an academic hospital in Sweden. The lack of a national electronic database for acute pain services made it a challenge to generalize the results to other hospitals. Valid comparisons among hospitals and regions will require methods that adjust for varying mixes of surgery and patient characteristics. The occurrence of adverse effects of pain treatment is influenced by multiple factors, an analysis of these factors would be the more detailed subject of a future study.

7 Implications for clinical practice

Patients with uncontrolled and problematic pain requiring multiple visits of the APS team have a high prevalence rate of psychiatric comorbidity, opioid dependency and non-surgical chronic pain. The assessment of psychiatric distress and support by mental health professionals working in the same team or near the APS team, should be considered in the multimodal therapy approaches instituted by the APS team.

8 Conclusions

Beside the benefits of the APS in the reduction of pain intensity, and in treating analgesia side effects, this study demonstrates the complicated role of the APS in the treatment of acute pain or “the changing face of acute pain”. The expectations of the APS have been shifted from the traditional treatment of acute surgical pain to the clinical challenges resulting from treating hospitalized patients with other primary problems and comorbidities. Perhaps the concept of an APS will ultimately be redefined according to the new clinical variables.

Highlights

Decrease in pain intensity resulted after APSintervention.
A shift in the focus of APS treatment was observed.
The concept of an APS needs to be redefined according to the new clinical variables.
The interdisciplinary APS team should include other specialties.

Multidisciplinary Pain Center, ing 79, Uppsala University Hospital, Sjukhusvägen, 75185 Uppsala, Sweden.

Conflict of interest: None declared.

Acknowledgements

The authors would like to help the following persons: Lenka Katila, Sylvia Augustini, Mia Berg, Marie Essemark for their contribution in acquisition of data, Torsten Gordh for support and encouragement, Mona-Lisa Wenroth for statistical consultation.

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Received: 2017-01-13

Revised: 2017-04-14

Accepted: 2017-04-30

Published Online: 2017-07-01

Published in Print: 2017-07-01

Articles in the same Issue

https://doi.org/10.1016/j.sjpain.2017.04.072

Keywords for this article

Acute pains services; Predictors of uncontrolled pain; Complications of pain treatment