Prescription Opioids and Brain Structure in Community-Dwelling Older Adults.

OBJECTIVE: To evaluate the associations between prescription opioid exposures in community-dwelling older adults and gray and white matter structure by magnetic resonance imaging. METHODS: Secondary analysis was conducted of a prospective, longitudinal population-based cohort study employing cross-sectional imaging of older adult (≥65 years) enrollees between November 1, 2004, and December 31, 2017. Gray matter outcomes included cortical thickness in 41 structures and subcortical volumes in 6 structures. White matter outcomes included fractional anisotropy in 40 tracts and global white matter hyperintensity volumes. The primary exposure was prescription opioid availability expressed as the per-year rate of opioid days preceding magnetic resonance imaging, with a secondary exposure of per-year total morphine milligram equivalents (MME). Multivariable models assessed associations between opioid exposures and brain structures. RESULTS: The study included 2185 participants; median (interquartile range) age was 80 (75 to 85) years, 47% were women, and 1246 (57%) received opioids. No significant associations were found between opioids and gray matter. Increased opioid days and MME were associated with decreased white matter fractional anisotropy in 15 (38%) and 16 (40%) regions, respectively, including the corpus callosum, posterior thalamic radiation, and anterior limb of the internal capsule, among others. Opioid days and MME were also associated with greater white matter hyperintensity volume (1.02 [95% CI, 1.002 to 1.036; P=.029] and 1.01 [1.001 to 1.024; P=.032] increase in the geometric mean, respectively). CONCLUSION: The duration and dose of prescription opioids were associated with decreased white matter integrity but not with gray matter structure. Future studies with longitudinal imaging and clinical correlation are warranted to further evaluate these relationships.

Low dose lofexidine for medically directed outpatient opioid tapering in adults with chronic pain: a prospective case series.

BACKGROUND: In adults with chronic pain, mild-to-moderate withdrawal symptoms during medically directed opioid tapering in the outpatient setting may not be accompanied by hypertension or tachycardia. This clinical scenario could limit the use of lofexidine at dosages reported in clinical trials of opioid withdrawal precipitated by abrupt opioid discontinuation. Thus, the primary aim of this prospective case series is to describe the use of low dose lofexidine for opioid withdrawal in patients with chronic pain undergoing medically directed opioid tapering in an outpatient setting. METHODS: Six patients (white 5, Latino 1) admitted to an outpatient interdisciplinary pain rehabilitation program met inclusion and exclusion criteria. Patients self-selected to undergo medically directed opioid tapering, and the medication the patients were prescribed upon admission was used in the taper schedule. Upon initiation of the opioid taper, patients received 0.18 mg of lofexidine every 6 hours. RESULTS: Five of the six patients were women, and the median morphine milligram equivalents at baseline were 36.9. The median taper duration was 15 days, and the median duration of lofexidine administration was 14 days. Withdrawal scores were mild throughout the taper in four patients, and two patients with fibromyalgia experienced single episodes of moderately severe withdrawal symptoms at the median morphine milligram equivalent midpoint of the taper. No hypotension or sustained bradycardia were observed, and no adverse effects related to lofexidine were reported. CONCLUSION: The observations from this prospective case series suggest that low-dose lofexidine may be a feasible adjunct medication to attenuate withdrawal symptoms in adults with chronic pain undergoing outpatient opioid tapering.

Substance Use Disorders: Basic Overview for the Anesthesiologist.

Substance use disorders (SUDs) represent a current major public health concern in the United States and around the world. Social and economic stressors secondary to the coronavirus disease 2019 (COVID-19) pandemic have likely led to an increase in SUDs around the world. This chronic, debilitating disease is a prevalent health problem, and yet many clinicians do not have adequate training or clinical experience diagnosing and treating SUDs. Anesthesiologists and other perioperative medical staff frequently encounter patients with co-occurring SUDs. By such, through increased awareness and education, physicians and other health care providers have a unique opportunity to positively impact the lives and improve the perioperative outcomes of patients with SUDs. Understanding commonly used terms, potentially effective perioperative screening tools, diagnostic criteria, basics of treatment, and the perioperative implications of SUDs is essential to providing adequate care to patients experiencing this illness.

Pain, Opioid Analgesics, and Cognition: A Conceptual Framework in Older Adults.

Chronic pain is highly prevalent in older adults and is associated with poor functional outcomes. Furthermore, opioid analgesics are commonly utilized for the treatment of pain in older adults despite well-described adverse effects. Importantly, both chronic pain and opioid analgesics have been linked with impairments in cognitive function, though data are limited. In this manuscript we summarize the evidence and critical knowledge gaps regarding the relationships between pain, opioid analgesics, and cognition in older adults. Furthermore, we provide a conceptual framework to guide future research in the development, implementation, and evaluation of strategies to optimize analgesic outcomes in older adults while minimizing deleterious effects on cognition.

Prescription opioids and longitudinal changes in cognitive function in older adults: A population-based observational study.

BACKGROUND: Opioids are frequently prescribed to alleviate pain in older adults, yet the relationships between prescription opioids and long-term cognitive function are unclear. METHODS: In this analysis of the Mayo Clinic Study of Aging, a longitudinal population-based cohort study of older adults with formal neuropsychological testing and cognitive evaluations performed every 15 months, the associations between prescription opioids, global and domain-specific cognitive function, and mild cognitive impairment were evaluated through time-dependent linear mixed effects and Cox proportional hazards models. RESULTS: Four thousand two hundred eighteen participants (51% male) were included with enrollment between 11/1/2004 and 4/1/2019 and median age of 76 (interquartile range 72, 82) years. Two thousand nine hundred seventy-seven subjects (71%) received at least 1 opioid prescription during a median follow-up of 7.5 (5.0, 10.7) years. Overall, there was an estimated 0.096 reduction in the global cognitive Z-score per year, including decreases of 0.050 in memory, 0.080 in language, 0.044 in visual-spatial cognition, and 0.112 in attention. In multivariable analyses, each receipt of an opioid prescription resulted in an additional -0.007 (95% CI -0.009, -0.005) change in global cognitive Z-score (p < 0.001), with significant effects seen in the domains of memory (-0.005, 95% CI -0.007, -0.003; p < 0.001), language (-0.002, 95% CI -0.003, 0.000; p = 0.024) and attention (-0.004, 95% CI -0.006, -0.002; p < 0.001) but not visual-spatial function (0.000, 95% CI -0.001, 0.001; p = 0.897). Opioid prescriptions were associated with incident mild cognitive impairment (MCI) in adjusted analysis (hazard ratio 1.21, 95% CI 1.04, 1.42; p = 0.014). CONCLUSION: Prescription opioids are associated with small but statistically significant declines in long-term cognitive function in older adults, which may represent effects of opioids or other related factors.

Disparities in Hypoxemia Detection by Pulse Oximetry Across Self-Identified Racial Groups and Associations With Clinical Outcomes.

OBJECTIVES: To assess disparities in hypoxemia detection by pulse oximetry across self-identified racial groups and associations with clinical outcomes. DESIGN: Observational cohort study from May 5, 2018, to December 31, 2020. SETTING: Three academic medical centers in the United States. PATIENTS: Adults greater than or equal to 18 years who self-identified as White, Black, Asian, or American Indian admitted to the ICU or undergoing surgery during inpatient hospitalization with simultaneous measurements of pulse oximetry-estimated oxygen saturation and arterial blood gas-derived oxygen saturation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Multivariable models were employed to assess the relationships between race, occult hypoxemia (i.e., arterial blood gas-derived oxygen saturation < 88% despite pulse oximetry-estimated oxygen saturation ≥ 92%), and clinical outcomes of hospital mortality and hospital-free days. One-hundred twenty-eight-thousand two-hundred eighty-five paired pulse oximetry-estimated oxygen saturation-arterial blood gas-derived oxygen saturation measurements were included from 26,603 patients. Pulse oximetry-estimated oxygen saturation on average overestimated arterial blood gas-derived oxygen saturation by 1.57% (1.54-1.61%). Black, Asian, and American Indian patients were more likely to experience occult hypoxemia during hospitalization (estimated probability 6.2% [5.1-7.6%], 6.6% [4.9-8.8%], and 6.6% [4.4-10.0%], respectively) compared with White patients (3.6% [3.4-3.8%]). Black patients had increased odds of occult hypoxemia compared with White patients after adjustment (odds ratio, 1.65; 1.28-2.14; p < 0.001). Differences in occult hypoxemia between Asian and American Indian patients compared with White patients were not significant after adjustment (odds ratio, 1.53; 0.95-2.47; p = 0.077 and odds ratio, 1.31; 0.80-2.16; p = 0.288, respectively). Occult hypoxemia was associated with increased odds of mortality in surgical (odds ratio, 2.96; 1.20-7.28; p = 0.019) and ICU patients (1.36; 1.03-1.80; p = 0.033). Occult hypoxemia was associated with fewer hospital-free days in surgical (-2.5 d [-3.9 to -1.2 d]; p < 0.001) but not ICU patients (0.4 d [-0.7 to 1.4 d]; p = 0.500). CONCLUSIONS: Occult hypoxemia is more common in Black patients compared with White patients and is associated with increased mortality, suggesting potentially important outcome implications for undetected hypoxemia. It is imperative to validate pulse oximetry with expanded racial inclusion.

Perioperative Opioid Consumption and Clinical Outcomes in Surgical Patients With a Pre-existing Opioid-Based Intrathecal Drug Delivery System.

BACKGROUND: Intrathecal drug delivery systems (IDDS) have been utilized for over 3 decades for management of chronic pain and spasticity. Patients with IDDS may present for surgical procedures unrelated to the IDDS device, although data are limited regarding perioperative outcomes. METHODS: This is a historical matched cohort study conducted between January 1, 2007 and December 31, 2016 of patients with an opioid-based IDDS versus matched control patients undergoing surgery excluding interventional pain procedures. Patients in the IDDS group were matched with up to 2 patients without an IDDS. Multivariable regression analyses were utilized to assess differences in the primary outcome of cumulative perioperative opioid consumption (ie, intraoperative and postanesthesia care unit [PACU] opioid consumption), and opioid consumption during the first 24 and 72 postoperative hours. Postoperative clinical outcomes were also assessed including escalating oxygen requirements, naloxone administration, pain-sedation mismatch, and perioperative pain service consultation. RESULTS: A total of 321 surgeries were included, 112 with IDDS and 209 controls, with median (interquartile range [IQR]) age of 57 (49-64) years. Compared to matched controls, patients with an IDDS had greater perioperative opioid consumption (median [IQR] oral morphine milligram equivalents [OME] of 110 [60-163] vs 93 [IQR, 53-142]; adjusted multiplicative increase 1.28 [95% confidence interval {CI}, 1.03-1.59]; P = .026). IDDS patients also had greater opioid consumption in the first 24 and 72 postoperative hours (multiplicative increases of 2.23 [95% CI, 1.36-3.63], P = .001, and 2.46 [95% CI, 1.41-4.32], P = .002, respectively). There were no significant differences in postoperative oxygen requirements, naloxone administration, or pain-sedation mismatch. Inpatient pain medicine consultation was more frequent in IDDS patients compared to controls (51.8% vs 6.2%; P < .001). CONCLUSIONS: Patients with opioid-based IDDS received more perioperative opioids and were more likely to receive postoperative pain service consultation compared to matched controls. There were no significant differences in clinical safety outcomes, suggesting tolerance for higher opioid doses. Further research is warranted to optimize perioperative outcomes in those with IDDS.

Peripheral Nerve Blockade with Combined Standard and Liposomal Bupivacaine in Major Lower-Extremity Amputation.

BACKGROUND AND OBJECTIVES: Optimizing perioperative analgesia for patients undergoing major lower-extremity amputation remains a considerable challenge. The utility of liposomal bupivacaine as a component of peripheral nerve blockade for lower-extremity amputation is unknown. METHODS: We conducted an observational study comparing three different perioperative analgesic techniques for adults undergoing major lower-extremity amputation under general anesthesia between 2012 and 2017 at an academic medical center: (1) no regional anesthesia, (2) peripheral nerve blockade with standard bupivacaine, and (3) peripheral nerve blockade with a mixture of standard and liposomal bupivacaine. The primary outcome of cumulative opioid oral morphine milligram equivalent utilization in the first 72 hours postoperatively was compared across groups utilizing multivariable linear regression. RESULTS: A total of 631 unique anesthetics were included for 578 unique patients, including 416 (66%) without regional anesthesia, 131 (21%) with peripheral nerve blockade with a mixture of standard and liposomal bupivacaine, and 84 (13%) with peripheral nerve blockade with standard bupivacaine alone. Cumulative morphine equivalents were lower in those receiving peripheral nerve blockade with combined standard and liposomal bupivacaine compared with those not receiving regional anesthesia (multiplicative increase 0.67; 95% CI 0.50 to 0.90; P = 0.007). There were no significant differences in opioid utilization between peripheral nerve blockade groups (P = 0.59). CONCLUSIONS: Peripheral nerve blockade is associated with reduced opioid requirements after lower-extremity amputation compared with general anesthesia alone. However, the incorporation of liposomal bupivacaine is not significantly different to blockade employing only standard bupivacaine.

Impact of Perioperative Pain Control on Knee Range of Motion and Development of Arthrofibrosis Following Primary Total Knee Arthroplasty.

BACKGROUND: Inadequate pain control following total knee arthroplasty (TKA) has been postulated to negatively impact knee range of motion (ROM). We sought to determine the association between perioperative pain levels and knee ROM at 3-month follow-up or need for manipulation under anesthesia (MUA). METHODS: We retrospectively reviewed 2243 primary TKAs performed from 2002 to 2019 at a single academic center using an institutional total joint registry. Mean age was 68, mean body mass index was 32.8, and 59% were female. Knee ROM was measured preoperatively and 3 months postoperatively. Change in knee ROM, rates of soft tissue contracture, and MUA were assessed in relation to in-hospital 10-point pain visual analog scale (VAS) measurements. RESULTS: Overall, 44% had improved ROM at 3-month follow-up, 29% had no change in ROM, and 27% had worsened ROM. There was no significant difference in mean VAS scores of patients with improved, unchanged, or worsened ROM postoperatively (3.0 vs 2.8 vs 3.0; P = .068). There was no significant difference in mean VAS scores of patients who developed a soft tissue contracture or required MUA vs those who did not develop these complications (2.7 vs 2.9; P = .24). Similarly, no significant relationship with these outcomes was identified when maximum and discharge VAS scores were analyzed. CONCLUSION: Comparable ROM and rates of MUA based on in-hospital pain levels were observed in this large series of primary TKA patients. While significant early pain may limit participation in ROM exercises initially, this does not appear to have a marked impact on ROM-related complications for most patients. LEVEL OF EVIDENCE: III, Therapeutic.

Peripheral Nerve Stimulation and Clinical Outcomes: A Retrospective Case Series.

PURPOSE: Peripheral nerve stimulation (PNS) is a rapidly expanding field within neuromodulation; however, there is limited data on therapeutic efficacy. This study describes the indications and clinical outcomes for patients undergoing PNS for chronic pain states. PATIENTS AND METHODS: This is a retrospective case series of adults undergoing PNS implantation from 2004 to 2017 at an academic medical center. The primary outcomes were changes in numeric rating scale (NRS) pain scores, opioid utilization in oral morphine milligram equivalent (MME), and self-reported patient functioning at 6 months postoperatively. Infectious and device-related complications were also assessed. RESULTS: A total of 72 patients underwent PNS implantation, including 59 patients that received a preceding PNS trial (59/78; 76% progression rate) and 13 that did not receive a PNS trial. The most common indication for stimulation was occipital neuralgia (47%) followed by lower-extremity neuropathies (17%). PNS implantation was associated with 6-month reductions in pain scores (7 [6, 8] baseline vs. 4 [2, 5] 6 months; P < 0.001) and opioid utilization (eg, median 60 [31, 104] vs. 18 [0, 52] MME among those with baseline opioid use; P < 0.001). Median functional improvement was 73% (50%, 88%). Seven patients (10%) suffered a postoperative surgical site infection at a median of 50 (30, 124) days, of which five devices were removed. CONCLUSION: Peripheral nerve stimulation was associated with reduced pain scores, lower opioid utilization, and improved patient function at 6 months. These data support PNS as a potentially effective nonopioid analgesic modality in chronic pain, though prospective multicenter evaluation is warranted to evaluate longer-term outcomes.

Abdominal Ice after Laparoscopic Hysterectomy: A Randomized Controlled Trial.

STUDY OBJECTIVE: To assess the impact of abdominal ice packs on opioid use and pain control after laparoscopic hysterectomy DESIGN: Randomized controlled trial. SETTING: Academic tertiary care medical center. PATIENTS: Total of 142 adult women undergoing laparoscopic (either conventional or robotic) hysterectomy were randomized to control (n = 69) or intervention (n = 73). Exclusion criteria included preoperative opioid use, planned intensive care unit admission or same-day discharge, an incision ≥4 cm, and regional anesthesia use. INTERVENTIONS: Subjects in the intervention group had a large ice pack placed directly on the lower abdomen before leaving the operating room. The ice pack was maintained continuously for 12 hours postoperation, as desired thereafter until discharge, and continued use encouraged after discharge for up to 48 hours. MEASUREMENTS AND MAIN RESULTS: Total opioids administered postoperatively, while inpatient and after dismissal, were assessed in morphine milligram equivalents. Postoperative pain, as well as analgesia acceptability and side effects, were assessed using validated measures: Brief Pain Inventory and Overall Benefit of Analgesia Score. Median morphine milligram equivalent was lower in the intervention group than the controls from inpatient stay on the floor to completion of opioid use as an outpatient (22.5 vs 26.2) but was not statistically significant (p = .79). There was no significant difference between the groups in Brief Pain Inventory assessment of postoperative pain severity (p = .80) or pain interference (p = .36) or Overall Benefit of Analgesia Score total score (p = .88). Most patients in the intervention group were very satisfied with ice pack use (n = 51, 79.7%) and very likely to recommend it to friends or family (n = 54, 83.1%). There were no adverse events related to ice pack use. CONCLUSION: There was no significant difference in postoperative opioid use or pain assessment with ice pack use after laparoscopic hysterectomy. However, most of the subjects expressed high satisfaction specific to ice pack use and would recommend its use to others, suggesting potential desirability as adjunct therapy in postoperative pain control.

The System Is Broken: A Qualitative Assessment of Opioid Prescribing Practices After Spine Surgery.

OBJECTIVE: To elucidate factors that influence opioid prescribing behaviors of key stakeholders after major spine surgery, with a focus on barriers to optimized prescribing. METHODS: In-person semi-structured interviews were performed with 20 surgical and medical professionals (January 23, 2019 to June 11, 2019) at a large academic medical center, including resident physicians, midlevel providers, attending physicians, and clinical pharmacists. Interviews centered on perceptions of postoperative prescribing practices were coded and analyzed using a qualitative inductive approach. RESULTS: Several unique themes emerged. First, wide interprovider variation exists in the perceived role of opioid prescribing guidelines. Second, there are important relationships between clinical experience, time constraints, and postoperative opioid prescribing. Third, opioid tapering is a major area of inconsistency. Fourth, there are serious challenges in managing analgesic expectations, particularly in those with chronic pain. Finally, there is currently no process to facilitate the hand-off or transition of opioid prescribing responsibility between surgical and primary care teams, which represents a major area for practice optimization efforts. CONCLUSION: Despite increased focus on postoperative opioid prescribing, there remain numerous areas for improvement. The development of tools and processes to address critical gaps in postoperative prescribing will be essential for our efforts to reduce long-term opioid use after major spine surgery and improve patient care.

Association Between Spine Surgery and Availability of Opioid Medication.

Importance: Prolonged prescribing of opioids after spine surgery is often perceived as a negative outcome, but successful opioid reduction may occur despite continued prescribing. Improved characterization of opioid availability before and after surgery is necessary to identify these successes. Objective: To evaluate the association between spine surgery and modification of opioid availability postoperatively by using consistent definitions to classify opioid availability before and after surgery. Design, Setting, and Participants: This population-based cohort study included 2223 adults (age ≥18 years) who underwent spine surgery in Olmsted County, Minnesota, from January 1, 2005, through December 31, 2016. Data were analyzed from April 1, 2019, to December 1, 2019. Exposures: Preoperative opioid availability based on prescription data in the 180 days before surgery in accordance with Consortium to Study Opioid Risks and Trends (CONSORT) definitions. Main Outcomes and Measures: Successful modification of opioid availability, defined as an improvement in CONSORT status postoperatively (assessed from 181 to 365 days after surgery) compared with preoperative status, or continued absence of opioid availability for patients with no preoperative availability. Multivariable logistic regression was used to assess the association between preoperative opioid availability and successful modification by 1 year after undergoing surgery. Results: Of 2223 patients included in the study, 1214 were male (54.6%), with a median age of 55 years (interquartile range, 43-68) years. Patients were classified as having no (778 [35.0%]), short-term (1118 [50.3%]), episodic (227 [10.2%]), or long-term (100 [4.5%]) preoperative opioid availability. Of the 2148 patients (96.6%) who were alive at 1 year, postoperative opioid availability was classified as no (1583 [73.7%]), short-term (398 [18.5%]), episodic (104 [4.8%]), and long-term (63 [2.9%]). A total of 1672 patients (77.8%) had successful modification of opioid availability, with success of 83.0% for those with no preoperative availability, 74.9% for those with short-term preoperative availability, 79.8% for those with episodic preoperative availability, and 64.4% for those with long-term preoperative opioid availability. In multivariable analysis, success was significantly associated with preoperative opioid availability (odds ratio [OR] for short term, 0.61 [95% CI, 0.48-0.77]; OR for episodic, 0.95 [95% CI, 0.64-1.40]; OR long term, 0.49 [95% CI, 0.30-0.82]; P < .001 overall vs no availability). Conclusions and Relevance: In this study, when following standardized CONSORT definitions, 4 of 5 adults undergoing spine surgery in a population-based cohort met the criteria for a successful pattern of postoperative opioid prescribing. Similar methods to objectively assess changes in opioid prescribing may be clinically useful in other perioperative settings.

A Practical Approach for the Management of the Mixed Opioid Agonist-Antagonist Buprenorphine During Acute Pain and Surgery.

The use of buprenorphine, a mixed opioid agonist-antagonist, for the management of chronic pain and/or opioid use disorder is increasing. As such, medical providers will more frequently encounter patients on this therapy. In this paper, we synthesize existing knowledge (derived through keyword searches using MEDLINE databases) in a novel conceptual framework for patients on buprenorphine presenting with acute pain or for those requiring surgical or invasive procedures. This framework is based on three unique domains: the patient, the features of the acute pain insult, and the environment. We discuss important considerations regarding the unique aspects of buprenorphine formulations and dosing, and we describe the importance of multidisciplinary planning and multimodal analgesic strategies. We also highlight important differences in management strategies based upon the presence or absence of opioid use disorder. All medical providers must be prepared to guide the patient on buprenorphine safely through the acute care episode, which includes adequate treatment of acute pain and avoidance of iatrogenic harm, including both short-term complications (eg, respiratory depression) and long-term complications (eg, relapse to opioid use).