Chronic Opioid Use and Central Sleep Apnea

Gender differences in sleep quality among Iranian traditional and industrial drug users

•The findings emphasize gender differences in sleep quality among different cultures, races, and ethnicities.•There are gender differences in sleep quality in Iranian traditional and industrial drug users.•Industrial drug users have a lower quality of sleep than traditional drug users.•The sleep quality of drug users (traditional and industrial) is lower than that of healthy people.

Potential vicious cycle between postoperative pain and sleep disorders: A bibliometric analysis

Background

Surgical pain affects postoperative sleep quality, and they jointly form a vicious cycle of mutual influence. The cycle of postoperative pain and sleep disorders could lead to delirium, cardiovascular disease, and hyperalgesia, which significantly affect patients' postoperative recovery. Thus, exploring this phenomenon is of great importance for surgical patients, and warrants further investigation.

Objective

By employing bibliometric methods, this study systematically analyzes the publications on postoperative pain-sleep disorders, identifies research trends and field dynamics, and ultimately provides insights for further progress in this research area.

Methods

In this study, we searched the Web of Science database for studies on postoperative pain and sleep disorders from 2013 to 2023, and analyzed the number of publications, journals, authors, institutions, country regions, and keywords by utilizing CiteSpace, VOSviewer, and Bibliometrix.

Results

The 1894 retrieved publications showed a trend of increasing number of publications and correlations between postoperative pain and sleep disorders from 2013 to 2023. The top countries for publications included the USA, China, etc., establishing a global collaborative network centered around the USA, China, and Europe. The top institutions for publications included University of California System, Harvard University, etc. The top authors include Christine Miaskowski, Steven M. Paul, Qiuling Shi, etc. These publications involved multiple disciplines including surgery, neurology, and anesthesiology, and various research funds including NIH, HHS, NSFC, etc. The top journals for publications included the European Archives of Oto-Rhino-Laryngology, etc. Keywords that appear most frequently in this field include "pain", "surgery", "quality of life", "sleep", "depression", and "outcomes". The thematic map indicated that the hot topics in this area include obstructive sleep apnea, tonsillectomy, children, pain, quality of life, and sleep. The undeveloped topics with research potential included postoperative pain, analgesia and dexmedetomidine, breast cancer, fatigue, and lung cancer.

Conclusion

The increased number of publications and correlations between postoperative pain and sleep disorders, and the collaborative network across the USA, China, and Europe indicate a growing global interest in this area. This study also provides valuable insights into the trend of hot topics and frontiers and shows that this is an evolving and dynamic research area.

Medication-induced central sleep apnea: a unifying concept

Medication-induced central sleep apnea (CSA) is one of the eight categories of causes of CSA but in the absence of awareness and careful history may be misclassified as primary CSA. While opioids are a well-known cause of respiratory depression and CSA, non-opioid medications including sodium oxybate, baclofen, valproic acid, gabapentin, and ticagrelor are less well-recognized. Opioids-induced respiratory depression and CSA are mediated primarily by µ-opioid receptors, which are abundant in the pontomedullary centers involved in breathing. The non-opioid medications, sodium oxybate, baclofen, valproic acid, and gabapentin, act upon brainstem gamma-aminobutyric acid (GABA) receptors, which co-colonize with µ-opioid receptors and mediate CSA. The pattern of ataxic breathing associated with these medications is like that induced by opioids on polysomnogram. Finally, ticagrelor also causes periodic breathing and CSA by increasing central chemosensitivity and ventilatory response to carbon dioxide. Given the potential consequences of CSA and the association between some of these medications with mortality, it is critical to recognize these adverse drug reactions, particularly because discontinuation of the offending agents has been shown to eliminate CSA.

The Impact of Nonpharmacological Interventions on Opioid Use for Chronic Noncancer Pain: A Scoping Review

Despite the lack of evidence, opioids are still routinely used as a solution to long-term management for chronic noncancer pain (CNCP). Given the significant risks associated with long-term opioid use, including the increased number of unregulated opioid pills at large in the opioid ecosystem, opioid cessation or reduction may be the desired goal of the patient and clinician. Viable nonpharmacological interventions (NPIs) to complement and/or replace opioids for CNCP are needed. Comprehensive reviews that address the impact of NPIs to help adults with CNCP reduce opioid use safely are lacking. We conducted a literature search in PubMed, CINAHL, Embase, PsycINFO, and Scopus for studies published in English. The initial search was conducted in April 2021, and updated in January 2024. The literature search yielded 19,190 relevant articles. Thirty-nine studies met the eligibility criteria and underwent data extraction. Of these, nineteen (49%) were randomized controlled trials, eighteen (46%) were observational studies, and two (5%) were secondary analyses. Among adults with CNCP who use opioids for pain management, studies on mindfulness, yoga, educational programs, certain devices or digital technology, chiropractic, and combination NPIs suggest that they might be an effective approach for reducing both pain intensity and opioid use, but other NPIs did not show a significant effect (e.g., hypnosis, virtual reality). This review revealed there is a small to moderate body of literature demonstrating that some NPIs might be an effective and safe approach for reducing pain and opioid use, concurrently.

Nationwide Analysis of Risk Factors Related to Opioid Weaning Following Lumbar Decompression Surgery - A Retrospective Database Study

BACKGROUND

Opioids are often prescribed for patients who eventually undergo lumbar decompression. Given the potential for opioid-related morbidity and mortality, postoperative weaning is often a goal of surgery. The purpose of this study was to examine the relationship between preoperative opioid use and postoperative complete opioid weaning among lumbar decompression patients.

METHODS

We surveyed the IBM Marketscan Databases for patients who underwent lumbar decompression during 2008-2017, had >30 days of opioid use in the year preceding surgery, and consumed a daily average of >0 morphine milligram equivalents in the 3 months preceding surgery. We used multivariable logistic regression and marginal standardization to examine the association between preoperative opioid use duration, average daily dose, and their interactions with complete opioid weaning in the 10-12 months after surgery.

RESULTS

Of the 11,114 patients who met inclusion criteria, most (54.7%, n = 6083) had a preoperative average daily dose of 1-20 morphine milligram equivalents. Postoperatively, 6144 patients (55.3%) remained on opioids. For patients with >180 days of preoperative use, the adjusted probability of weaning increased as the preoperative dose decreased. Obesity increased the likelihood of weaning, whereas older age, several comorbidities, female sex, and Medicaid decreased the odds of weaning.

CONCLUSIONS

Patients who used opioids for longer preoperatively were less likely to completely wean following surgery. Among patients with >180 days of preoperative use, those with lower preoperative doses were more likely to wean. Weaning was also associated with several clinical and demographic factors. These findings may help shape expectations regarding opioid use following lumbar decompression.

IUPHAR Review: New strategies for medications to treat substance use disorders

Substance use disorders (SUDs) and drug overdose are a public health emergency and safe and effective treatments are urgently needed. Developing new medications to treat them is expensive, time-consuming, and the probability of a compound progressing to clinical trials and obtaining FDA-approval is low. The small number of FDA-approved medications for SUDs reflects the low interest of pharmaceutical companies to invest in this area due to market forces, characteristics of the population (e.g., stigma, and socio-economic and legal disadvantages), and the high bar regulatory agencies set for new medication approval. In consequence, most research on medications is funded by government agencies, such as the National Institute on Drug Abuse (NIDA). Multiple scientific opportunities are emerging that can accelerate the discovery and development of new medications for SUDs. These include fast and efficient tools to screen new molecules, discover new medication targets, use of big data to explore large clinical data sets and artificial intelligence (AI) applications to make predictions, and precision medicine tools to individualize and optimize treatments. This review provides a general description of these new research strategies for the development of medications to treat SUDs with emphasis on the gaps and scientific opportunities. It includes a brief overview of the rising public health toll of SUDs; the justification, challenges, and opportunities to develop new medications; and a discussion of medications and treatment endpoints that are being evaluated with support from NIDA.

Simultaneous selection and inference for varying coefficients with zero regions: a soft-thresholding approach

Varying coefficient models have been used to explore dynamic effects in many scientific areas, such as in medicine, finance, and epidemiology. As most existing models ignore the existence of zero regions, we propose a new soft-thresholded varying coefficient model, where the coefficient functions are piecewise smooth with zero regions. Our new modeling approach enables us to perform variable selection, detect the zero regions of selected variables, obtain point estimates of the varying coefficients with zero regions, and construct a new type of sparse confidence intervals that accommodate zero regions. We prove the asymptotic properties of the estimator, based on which we draw statistical inference. Our simulation study reveals that the proposed sparse confidence intervals achieve the desired coverage probability. We apply the proposed method to analyze a large-scale preoperative opioid study.

Sleep apnea pathophysiology

OBJECTIVE

The purpose of this study is to examine the pathophysiology underlying sleep apnea (SA).

BACKGROUND

We consider several critical features of SA including the roles played by the ascending reticular activating system (ARAS) that controls vegetative functions and electroencephalographic findings associated with both SA and normal sleep. We evaluate this knowledge together with our current understanding of the anatomy, histology, and physiology of the mesencephalic trigeminal nucleus (MTN) and mechanisms that contribute directly to normal and disordered sleep. MTN neurons express γ-aminobutyric acid (GABA) receptors which activate them (make chlorine come out of the cells) and that can be activated by GABA released from the hypothalamic preoptic area.

METHOD

We reviewed the published literature focused on sleep apnea (SA) reported in Google Scholar, Scopus, and PubMed databases.

RESULTS

The MTN neurons respond to the hypothalamic GABA release by releasing glutamate that activates neurons in the ARAS. Based on these findings, we conclude that a dysfunctional MTN may be incapable of activating neurons in the ARAS, notably those in the parabrachial nucleus, and that this will ultimately lead to SA. Despite its name, obstructive sleep apnea (OSA) is not caused by an airway obstruction that prevents breathing.

CONCLUSIONS

While obstruction may contribute to the overall pathology, the primary factor involved in this scenario is the lack of neurotransmitters.

Predictors of Initial CPAP Prescription and Subsequent Course with CPAP in Patients with Central Sleep Apneas at a Single Center

PURPOSE

Guidelines recommend considering an initial trial of continuous positive airway pressure (CPAP) to treat central sleep apnea (CSA). However, practice patterns vary widely. This study investigated predictors for an initial trial of CPAP in patients with central apneas and whether those factors predict adequate treatment response in patients receiving an initial CPAP trial.

METHODS

Charts of patients receiving a diagnostic code for CSA following a sleep study during 2016-2018 at a single center were reviewed. Patient factors, initial treatment prescriptions, and subsequent changes to therapy were extracted from electronic health records. Regression models were used to estimate factors associated with an initial CPAP prescription and the likelihood of an adequate CPAP response (no subsequent therapy change and no discontinuation of therapy) among patients prescribed CPAP.

RESULTS

429/588 (73%) patients with central apneas received an initial trial of CPAP. Younger age, diagnosis by home sleep testing, non-opiate etiology of central apneas, and a lower proportion of central apneas at diagnosis were independently associated with a higher likelihood of an initial CPAP trial. A lower proportion of central apneas was associated with a higher probability of adequate response, while current smoking and opiate-related central apneas predicted an unsuccessful CPAP trial. A new finding was that older age predicted a lower likelihood of an initial CPAP prescription but did not predict an unsatisfactory response to CPAP.

CONCLUSION

Clinicians may incorrectly weigh certain clinical and sleep study characteristics when deciding whether to trial CPAP for patients with central apneas.

Daily treatment with the dual orexin receptor antagonist DORA-12 during oxycodone abstinence decreases oxycodone conditioned reinstatement

Chronic opioid use disturbs circadian rhythm and sleep, encouraging opioid use and relapse. The orexin (OX) system is recruited by opioids and regulates physiological processes including sleep. Dual OX receptor antagonists (DORAs), developed for insomnia treatment, may relieve withdrawal-associated sleep disturbances. This study investigated whether DORA-12, a recently developed DORA, reduces physiological activity disturbances during oxycodone abstinence and consequently prevents oxycodone-seeking behavior. Male and female Wistar rats were trained to intravenously self-administer oxycodone (0.15 mg/kg, 21 sessions; 8 h/session) in the presence of a contextual/discriminative stimulus (SD). The rats were subsequently housed individually (22 h/day) to monitor activity, food and water intake. They received DORA-12 (0-30 mg/kg, p.o.) after undergoing daily 1-h extinction training (14 days). After extinction, the rats were tested for oxycodone-seeking behavior elicited by the SD. Hypothalamus sections were processed to assess oxycodone- or DORA-12-associated changes to the OX cell number. In males, oxycodone-associated increases in activity during the light-phase, reinstatement, and decreases in the number of OX cells observed in the vehicle-treated group were not observed with DORA-12-treatment. Oxycodone-associated increases in light-phase food and water intake were not observed by day 14 of 3 mg/kg DORA-12-treatment and dark-phase water intake was increased across treatment days. In females, OX cell number was unaffected by oxycodone or DORA-12. Three and 30 mg/kg DORA-12 increased females' day 7 dark-phase activity and decreased reinstatement. Thirty mg/kg DORA-12 reduced oxycodone-associated increases in light-phase food and water intake. The results suggest that DORA-12 improves oxycodone-induced disruptions to physiological activities and reduces relapse.

Methadone Dose and Timing of Administration as Predictors of Sleep Apnea Syndrome During Methadone Maintenance Treatment: A Retrospective Cross-sectional Study

Background

This study aimed to assess the association of sleep apnea syndrome (SAS) with methadone dose and timing of administration in patients receiving methadone maintenance treatment (MMT) for opioid use disorder (OUD).

Methods

This retrospective cross-sectional study was conducted on adult patients receiving MMT who had a nocturnal respiratory polygraphy between November 2015 and December 2021. Data on methadone treatment and polygraph recording, including the apnea-hypopnea index (AHI) were collected.

Findings

A total of 40 patients, mostly male (72.5%), with a mean age of 35±6.7 years and a mean body mass index (BMI) of 25.1±4.5 kg/m2 were included. The daily dose of methadone was significantly associated with an AHI≥15 events/h as well as an AHI≥30 events/h, even after adjustment for age, gender, BMI, and benzodiazepine use. However, these associations were not preserved when the time of administration (day vs evening) was considered, while the evening administration was significantly associated with an AHI≥15 events/h. The best sensitivity and specificity for the prediction of AHI≥15 events/h and AHI≥30 events/h were obtained with daily methadone doses of≥72.5 mg and 77.5 mg, respectively.

Conclusion

In this sample of MMT patients, methadone doses of 72.5 mg and 77.5 mg were the best cut-off values for predicting AHI≥15 and≥30 events/h, respectively, especially when taken in the evening. These results should draw clinicians' attention to the importance of SAS screening, and further studies are needed, notably comparisons with buprenorphine.

Sleep and critical illness: a review

Critical illness and stays in the Intensive Care Unit (ICU) have significant impact on sleep. Poor sleep is common in this setting, can persist beyond acute critical illness, and is associated with increased morbidity and mortality. In the past 5 years, intensive care clinical practice guidelines have directed more focus on sleep and circadian disruption, spurring new initiatives to study and improve sleep complications in the critically ill. The global SARS-COV-2 (COVID-19) pandemic and dramatic spikes in patients requiring ICU level care also brought augmented levels of sleep disruption, the understanding of which continues to evolve. This review aims to summarize existing literature on sleep and critical illness and briefly discuss future directions in the field.

Predictors of Initial CPAP Prescription and Subsequent Course with CPAP in Patients with Central Sleep Apneas

Purpose

Guidelines recommend considering an initial trial of continuous positive airway pressure (CPAP) to treat central sleep apnea (CSA). However, practice patterns vary widely. This study investigated predictors for an initial trial of CPAP in patients with central apneas and whether those factors predict adequate treatment response in patients receiving an initial CPAP trial.

Methods

Charts of patients receiving a diagnostic code for CSA following a sleep study during 2016-2018 at a single center were reviewed. Patient factors, initial treatment prescriptions, and subsequent changes to therapy were extracted from electronic health records. Regression models were used to estimate factors associated with an initial CPAP prescription and the likelihood of an adequate CPAP response (no subsequent therapy change or nonadherence) among patients prescribed CPAP.

Results

429/588 (73%) patients with central apneas received an initial trial of CPAP. Younger age, diagnosis by home sleep testing, non-opiate etiology of central apneas, and a lower proportion of central apneas at diagnosis were independently associated with a higher likelihood of an initial CPAP trial. A lower proportion of central apneas was associated with a higher probability of adequate response, while current smoking and opiate-related central apneas predicted an unsuccessful CPAP trial. A new finding was that older age predicted a lower likelihood of an initial CPAP prescription but did not predict a suboptimal response to CPAP.

Conclusion

Clinicians may incorrectly weigh certain clinical and sleep study characteristics when deciding whether to trial CPAP for patients with central apneas.

Sleep disorders in chronic pain and its neurochemical mechanisms: a narrative review

Chronic pain (CP) is a prevalent problem, and more than half of patients with CP have sleep disorders. CP comorbidity with sleep disorders imposes immense suffering and seriously affects the patient's quality of life, which is a challenging issue encountered by clinicians. Although the reciprocal interactions between pain and sleep have been studied to some degree, there is still a lack of awareness and comprehensive description of CP comorbidity with sleep disorders. In this narrative review article, we summarize the current knowledge about the present estimates of the prevalence of comorbid sleep disorders in CP patients, sleep detection methods, sleep characterization in CP, and the effect of sleep disorders on CP and current therapies. We also summarize current knowledge of the neurochemical mechanisms of CP comorbidity with sleep disorders. In conclusion, insufficient attention has been paid to the role of sleep disorders in CP patients, and CP patients should be screened for sleep disorders in the clinic. Special attention should be given to a possible risk of drug-drug interaction when using two types of drugs targeting pain and sleep simultaneously. The current insight into the neurobiological mechanisms underlying CP comorbidity with sleep disorders is still rather limited.

Prevalence of preoperative opioid usage and its impact on postoperative outcomes: a retrospective cohort study

PURPOSE

Preoperative opioid treatment increases postoperative adverse events. This study was aimed to analyze preoperative opioid prevalence in countries with low opioid consumption. Additionally, the effect of low opioid usage on postoperative outcomes was also investigated.

METHODS

We conducted this single center retrospective cohort analysis in a Japanese university-affiliated hospital to investigate opioid usage and its impact on the duration of postoperative hospitalization and in-hospital mortality. Adult patients who underwent general anesthesia between 2015 and 2020 were included. We extracted the patients' characteristics, surgical information and postoperative outcomes. Subgroup analysis to address opioid dose effect was performed in high and low dose opioid subgroups.

RESULTS

Among 20,306 inpatients, 535 (2.63%) patients used opioids preoperatively. Tramadol was the most frequently used opioid. The median morphine equivalent (MME) dose was 15 mg/day. Median duration of hospitalization was 18 and 9 days in the opioid and non-opioid groups, and in-hospital mortality was 2.06% and 0.42%. Multivariable regression analysis demonstrated that preoperative opioid use was associated with a longer duration of hospitalization and in-hospital mortality. Subgroup analysis demonstrated longer durations of hospitalization in both high (> 30 mg/day MME) and low (≤ 30 mg/day MME) dose opioid groups, while higher in-hospital mortality was seen only in the high dose opioid group.

CONCLUSIONS

Preoperative opioid usage was one-tenth of the United States average. Despite its low prevalence and small dosage, preoperative opioid usage was associated with poor postoperative outcomes. Dedicated perioperative interventions to prevent opioid-associated adverse events should be developed even in countries with low opioid consumption.

Racial disparities in opioid prescription and pain management among breast cancer survivors

BACKGROUND

We examined whether there are racial disparities in pain management, opioid medicine prescriptions, symptom severity, and quality of life constructs in breast cancer survivors.

METHODS

We conducted a secondary analysis of longitudinal data from the Women's Hormonal Therapy Initiation and Persistence (WHIP) study (n = 595), a longitudinal study of hormonal receptor-positive breast cancer survivors. Upon study enrollment, patients completed a survey assessing an array of psychological, behavioral, and treatment outcomes, including adjuvant endocrine therapy (AET)-induced symptoms, and provided a saliva biospecimen. Opioid prescription records were extracted from the health maintenance organizations (HMOs) pharmacy database. The final analytic sample included women with complete HMO pharmacy records for 1 year.

RESULTS

There were 251 eligible patients, of which 169 (67.3%) were White. The average age was 61.09 years old (SD = 11.07). One hundred seventy-two patients (68.5%) had received at least one opioid medication and 37.1% were prescribed opioids longer than 90 days (n = 93). Sixty-four Black patients (78%) had a record of being prescribed with opioids compared to 64% of White patients (n = 108, p = 0.03). Black patients reported worse vasomotor, neuropsychological, and gastrointestinal symptoms, as well as lower quality of life and greater healthcare discrimination than White patients (p's < 0.05). Black patients were more likely to be prescribed opioids for 90 days or longer compared to White patients, when controlling for age, marital status, income, body mass index (BMI), cancer stage, and chemotherapy status (adjusted Odds Ratio = 2.72, p = 0.014).

CONCLUSION

Findings indicate that there are racial differences in opioid prescriptions supplied for pain management and symptomatic outcomes. Future research is needed to understand the causes of disparities in cancer pain management and symptomatic outcomes.

Opioids, sleep, analgesia and respiratory depression: Their convergence on Mu (μ)-opioid receptors in the parabrachial area

Opioids provide analgesia, as well as modulate sleep and respiration, all by possibly acting on the μ-opioid receptors (MOR). MOR's are ubiquitously present throughout the brain, posing a challenge for understanding the precise anatomical substrates that mediate opioid induced respiratory depression (OIRD) that ultimately kills most users. Sleep is a major modulator not only of pain perception, but also for changing the efficacy of opioids as analgesics. Therefore, sleep disturbances are major risk factors for developing opioid overuse, withdrawal, poor treatment response for pain, and addiction relapse. Despite challenges to resolve the neural substrates of respiratory malfunctions during opioid overdose, two main areas, the pre-Bötzinger complex (preBötC) in the medulla and the parabrachial (PB) complex have been implicated in regulating respiratory depression. More recent studies suggest that it is mediation by the PB that causes OIRD. The PB also act as a major node in the upper brain stem that not only receives input from the chemosensory areas in medulla, but also receives nociceptive information from spinal cord. We have previously shown that the PB neurons play an important role in mediating arousal from sleep in response to hypercapnia by its projections to the forebrain arousal centers, and it may also act as a major relay for the pain stimuli. However, due to heterogeneity of cells in the PB, their precise roles in regulating, sleep, analgesia, and respiratory depression, needs addressing. This review sheds light on interactions between sleep and pain, along with dissecting the elements that adversely affects respiration.

Changes in Psychological Outcomes after Cessation of Full Mu Agonist Long-Term Opioid Therapy for Chronic Pain

Improved understanding of psychological features associated with full mu agonist long-term opioid therapy (LTOT) cessation may offer advantages for clinicians. This preliminary study presents changes in psychological outcomes in patients with chronic, non-cancer pain (CNCP) after LTOT cessation via a 10-week multidisciplinary program which included treatment with buprenorphine. Paired t-tests pre- and post-LTOT cessation were compared in this retrospective cohort review of data from electronic medical records of 98 patients who successfully ceased LTOT between the dates of October 2017 to December 2019. Indicators of quality of life, depression, catastrophizing, and fear avoidance, as measured by the 36-Item Short Form Survey, the Patient Health Questionnaire-9-Item Scale, the Pain Catastrophizing Scale, and the Fear Avoidance Belief Questionnaires revealed significant improvement. Scores did not significantly improve for daytime sleepiness, generalized anxiety, and kinesiophobia, as measured by the Epworth Sleepiness Scale, the Generalized Anxiety Disorder 7-Item Scale, and the Tampa Scale of Kinesiophobia. The results suggest that successful LTOT cessation may be interconnected with improvements in specific psychological states.

Joint longitudinal trajectories of pain intensity and opioid prescription in veterans with back pain

PURPOSE

We describe pain intensity and opioid prescription jointly over time in Veterans with back pain to better understand their relationship.

METHODS

We performed a retrospective cohort study on electronic health record data from 117 126 Veterans (mean age 49.2 years) diagnosed with back pain in 2015. We used latent class growth analysis to jointly model pain intensity (0-10 scores) and opioid prescriptions over 2 years to identify classes of individuals similar in their trajectory of pain and opioid over time. Multivariable multinomial logit models assessed sociodemographic and clinical predictors of class membership.

RESULTS

We identified six trajectory classes: a "no pain/no opioid" class (22.2%), a "mild pain/no opioid" class (45.0%), a "moderate pain/no opioid" class (24.6%), a "moderate, decreasing pain/decreasing opioid" class (3.3%), a "moderate pain/high opioid" class (2.6%), and a "moderate, increasing pain/increasing opioid" class (2.3%). Among those in moderate pain classes, being white (vs. non-white) and older were associated with higher odds of being prescribed opioids. Veterans with mental health diagnoses had increased odds of being in the painful classes versus "no pain/no opioid" class.

CONCLUSION

We found distinct patterns in the long-term joint course of pain and opioid prescription in Veterans with back pain. Understanding these patterns and associated predictors may help with development of targeted interventions for patients with back pain.

Opioid-related adverse drug reactions in patients visiting the emergency division of a tertiary hospital

Opioid use and associated morbidity and mortality have increased in several countries during the past 20 years. We performed a study whose objective was to assess the frequency and causes of opioid-related emergency division (ED) visits in an adult tertiary Swiss University Hospital over 9 weeks in 2018. We primarily assessed opioid-related adverse drug reactions (ADR), secondary overdose, misuse, abuse, and insufficient pain relief. Current opioid use was identified in 1037 (8.3%) of the 12 470 included ED visits. In 64 opioid users, an ADR was identified as a contributing cause of the ED visit, representing 6.2% of opioid users, and 0.5% of the total ED visits. Moreover, we identified an overdose in 16 opioid users, misuse or abuse in 19 opioid users, and compatible withdrawal symptoms in 7 opioid users. After pooling all these events, we conclude that the ED visits could be related to opioid use in 10.2% of opioid users. Finally, in 201 opioid users, insufficient pain relief (pain not responding to the current pharmacological treatment) was identified as a contributing cause of ED visits. In these cases, other factors than simply pharmacological nonresponse may have been involved. In the context of an ever-increasing opioid use to better control chronic pain situations, these results should reinforce emergency network epidemiological surveillance studies at a national level.

New pharmacologic agents for obstructive sleep apnoea: what do we know and what can we expect?

PURPOSE OF REVIEW

This review provides a condensed description of pharmacological remedies explored in patients with obstructive sleep apnoea (OSA) as well as projections of what we might expect in terms of clinical performance of these drugs.

RECENT FINDINGS

Conventional drug therapies explored in OSA have generally produced disappointing results and there is a shortage of pharmacological treatment alternatives in this disorder. Recent insights into pathophysiological mechanisms potentially involved in OSA suggest that the condition may be divided into distinct subgroups based on clusters or defined by means of unique functional endotypic criteria. In fact, positive outcomes in clinical trials have now resulted in several drug candidates that show a convincing reduction of sleep disordered breathing in both short and intermediate term. Such drugs may be particularly useful in certain variants of OSA but not in others. These insights have also raised the ambition to create personalized therapies in OSA. Another recent development is the insight that OSA-linked conditions such as obesity, daytime somnolence and various forms of cardiovascular/metabolic disease may provide drug-based targets. For instance, pharmacological obesity therapy may provide not only positive metabolic effects but may also be a way to eliminate the anatomic component in obese OSA patients.

SUMMARY

Recent insights into the pathophysiology of OSA have opened possibilities to develop personalized therapy. Drugs addressing fundamental aspects of the sleep and breathing disorder provide a particularly promising avenue for development of novel forms of treatment in OSA.

Non-invasive positive pressure ventilation for central sleep apnoea in adults

BACKGROUND

Central sleep apnoea (CSA) is characterised by abnormal patterns of ventilation during sleep due to a dysfunctional drive to breathe. Consequently, people with CSA may present poor sleep quality, sleep fragmentation, inattention, fatigue, daytime sleepiness, and reduced quality of life.

OBJECTIVES

To assess the effectiveness and safety of non-invasive positive pressure ventilation (NIPV) for the treatment of adults with CSA.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and Scopus on 6 September 2021. We applied no restrictions on language of publication. We also searched clinical trials registries for ongoing and unpublished studies, and scanned the reference lists of included studies to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) reported in full text, those published as abstract only, and unpublished data.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted data, and assessed risk of bias of the included studies using the Cochrane risk of bias tool version 1.0, and the certainty of the evidence using the GRADE approach. In the case of disagreement, a third review author was consulted.

MAIN RESULTS

We included 15 RCTs with a total of 1936 participants, ranging from 10 to 1325 participants. All studies had important methodological limitations. We assessed most studies (11 studies) as at high risk of bias for at least one domain, and all studies as at unclear risk of bias for at least two domains. The trials included participants aged > 18 years old, of which 70% to 100% were men, who were followed from one week to 60 months. The included studies assessed the effects of different modes of NIPV and CSA. Most participants had CSA associated with chronic heart failure. Because CSA encompasses a variety of causes and underlying clinical conditions, data were carefully analysed, and different conditions and populations were not pooled. The findings for the primary outcomes for the seven evaluated comparisons are presented below.  Continuous positive airway pressure (CPAP) plus best supportive care versus best supportive care in CSA associated with chronic heart failure In the short term, CPAP plus best supportive care may reduce central apnoea hypopnoea index (AHI) (mean difference (MD) -14.60, 95% confidence interval (CI) -20.11 to -9.09; 1 study; 205 participants). However, CPAP plus best supportive care may result in little to no difference in cardiovascular mortality compared to best supportive care alone. The evidence for the effect of CPAP plus best supportive care on all-cause mortality is very uncertain. No adverse effects were observed with CPAP, and the results for adverse events in the best supportive care group were not reported. Adaptive servo ventilation (ASV) versus CPAP in CSA associated with chronic heart failure The evidence is very uncertain about the effect of ASV versus CPAP on quality of life evaluated in both the short and medium term. Data on adverse events were not reported, and it is not clear whether data were sought but not found. ASV versus bilevel ventilation in CSA associated with chronic heart failure In the short term, ASV may result in little to no difference in central AHI. No adverse events were detected with ASV, and the results for adverse events in the bilevel ventilation group were not reported. ASV plus best supportive care versus best supportive care in CSA associated with chronic heart failure In the medium term, ASV plus best supportive care may reduce AHI compared to best supportive care alone (MD -20.30, 95% CI -28.75 to -11.85; 1 study; 30 participants). In the long term, ASV plus best supportive care likely increases cardiovascular mortality compared to best supportive care (risk ratio (RR) 1.25, 95% CI 1.04, 1.49; 1 study; 1325 participants). The evidence suggests that ASV plus best supportive care may result in little to no difference in quality of life in the short, medium, and long term, and in all-cause mortality in the medium and long term. Data on adverse events were evaluated but not reported. ASV plus best supportive care versus best supportive care in CSA with acute heart failure with preserved ejection fraction Only adverse events were reported for this comparison, and no adverse events were recorded in either group. ASV versus CPAP maintenance in CPAP-induced CSA In the short term, ASV may slightly reduce central AHI (MD -4.10, 95% CI -6.67 to -1.53; 1 study; 60 participants), but may result in little to no difference in quality of life. Data on adverse events were not reported, and it is not clear whether data were sought but not found. ASV versus bilevel ventilation in CPAP-induced CSA In the short term, ASV may slightly reduce central AHI (MD -8.70, 95% CI -11.42 to -5.98; 1 study; 30 participants) compared to bilevel ventilation. Data on adverse events were not reported, and it is not clear whether data were sought but not found.

AUTHORS' CONCLUSIONS

CPAP plus best supportive care may reduce central AHI in people with CSA associated with chronic heart failure compared to best supportive care alone. Although ASV plus best supportive care may reduce AHI in people with CSA associated with chronic heart failure, it likely increases cardiovascular mortality in these individuals. In people with CPAP-induced CSA, ASV may slightly reduce central AHI compared to bilevel ventilation and to CPAP. In the absence of data showing a favourable impact on meaningful patient-centred outcomes and defining clinically important differences in outcomes in CSA patients, these findings need to be interpreted with caution. Considering the level of certainty of the available evidence and the heterogeneity of participants with CSA, we could draw no definitive conclusions, and further high-quality trials focusing on patient-centred outcomes, such as quality of life, quality of sleep, and longer-term survival, are needed to determine whether one mode of NIPV is better than another or than best supportive care for any particular CSA patient group.

FORWARDS-1: an adaptive, single-blind, placebo-controlled ascending dose study of acute baclofen on safety parameters in opioid dependence during methadone-maintenance treatment-a pharmacokinetic-pharmacodynamic study

Background

Treatment of opiate addiction with opiate substitution treatment (e.g. methadone) is beneficial. However, some individuals desire or would benefit from abstinence but there are limited options to attenuate problems with opiate withdrawal. Preclinical and preliminary clinical evidence suggests that the GABA-B agonist, baclofen, has the desired properties to facilitate opiate detoxification and prevent relapse. This study aims to understand whether there are any safety issues in administering baclofen to opioid-dependent individuals receiving methadone.

Methods

Opiate-dependent individuals (DSM-5 severe opioid use disorder) maintained on methadone will be recruited from addiction services in northwest London (NHS and third sector providers). Participants will be medically healthy with no severe chronic obstructive pulmonary disease or type 2 respiratory failure, no current dependence on other substances (excluding nicotine), no current severe DSM-5 psychiatric disorders, and no contraindications for baclofen or 4800 IU vitamin D (placebo). Eligible participants will be randomised in a 3:1 ratio to receive baclofen or placebo in an adaptive, single-blind, ascending dose design. A Bayesian dose-escalation model will inform the baclofen dose (10, 30, 60, or 90 mg) based on the incidence of ‘dose-limiting toxicity’ (DLT) events and participant-specific methadone dose. A range of respiratory, cardiovascular, and sedative measures including the National Early Warning Score (NEWS2) and Glasgow Coma Scale will determine DLT. On the experimental day, participants will consume their usual daily dose of methadone followed by an acute dose of baclofen or placebo (vitamin D3) ~ 1 h later. Measures including oxygen saturation, transcutaneous CO₂, respiratory rate, QTc interval, subjective effects (sedation, drug liking, craving), plasma levels (baclofen, methadone), and adverse events will be obtained using validated questionnaires and examinations periodically for 5 h after dosing.

Discussion

Study outcomes will determine what dose of baclofen is safe to prescribe to those receiving methadone, to inform a subsequent proof-of-concept trial of the efficacy baclofen to facilitate opiate detoxification. To proceed, the minimum acceptable dose is 30 mg of baclofen in patients receiving ≤ 60 mg/day methadone based on the clinical experience of baclofen’s use in alcoholism and guidelines for the management of opiate dependence.

Trial registration

Clinicaltrials.gov NCT05161351. Registered on 16 December 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06821-9.

Opioid Use Disorder, Sleep Deficiency, and Ventilatory Control: Bidirectional Mechanisms and Therapeutic Targets

Opioid use continues to rise globally. So too do the associated adverse consequences. Opioid use disorder (OUD) is a chronic and relapsing brain disease characterized by loss of control over opioid use and impairments in cognitive function, mood, pain perception, and autonomic activity. Sleep deficiency, a term that encompasses insufficient or disrupted sleep due to multiple potential causes, including sleep disorders, circadian disruption, and poor sleep quality or structure due to other medical conditions and pain, is present in 75% of patients with OUD. Sleep deficiency accompanies OUD across the spectrum of this addiction. The focus of this concise clinical review is to highlight the bidirectional mechanisms between OUD and sleep deficiency and the potential to target sleep deficiency with therapeutic interventions to promote long-term, healthy recovery among patients in OUD treatment. In addition, current knowledge on the effects of opioids on sleep quality, sleep architecture, sleep-disordered breathing, sleep apnea endotypes, ventilatory control, and implications for therapy and clinical practice are highlighted. Finally, an actionable research agenda is provided to evaluate the basic mechanisms of the relationship between sleep deficiency and OUD and the potential for behavioral, pharmacologic, and positive airway pressure treatments targeting sleep deficiency to improve OUD treatment outcomes.

Practice recommendations for the role of physiotherapy in the management of sleep disorders: the 2022 Brazilian Sleep Association Guidelines

This clinical guideline supported by the Brazilian Sleep Association comprises a brief history of the development of Brazilian sleep physiotherapy, outlines the role of the physiotherapist as part of a sleep health team, and describes the clinical guidelines in respect of the management of some sleep disorders by the physiotherapist (including sleep breathing disorders, i.e., obstructive sleep apnea, central sleep apnea, upper airway resistance syndrome, hypoventilation syndromes and overlap syndrome, and pediatric sleep breathing disorders; sleep bruxism; circadian rhythms disturbances; insomnia; and Willis-Ekbom disease/periodic limb movement disorder. This clinical practice guideline reflects the state of the art at the time of publication and will be reviewed and updated as new information becomes available.

Chronic Opioid Use and Sleep Disorders

Opioid medications are considered a significant component in the multidisciplinary management of chronic pain. In the past two decades, the use of opioid medications has dramatically risen in part because of an increased awareness by health care providers to treat chronic pain more effectively. In addition, patients are encouraged to seek treatment. The release of a sentinel joint statement in 1997 by the American Academy of Pain Medicine and the American Pain Society in a national effort to increase awareness and support the treatment of chronic pain has undoubtedly contributed to the opioid crisis.

Prescribed opioid use is associated with adverse cardiovascular outcomes in community-dwelling older persons

AIMS

Prescribed opioids are commonly used in the older community-dwelling population for the treatment of chronic pain. Although the harmful effects of opioid abuse and overdose are well understood, little is known about the long-term cardiovascular (CV) effects of prescribed opioids. The aim of this study was to investigate the CV effects associated with prescribed opioid use.

METHODS AND RESULTS

A post hoc analysis of participants in the Aspirin in Reducing Events in the Elderly (ASPREE) trial was conducted. Participants in the ASPREE trial included community-dwelling older adults without a prior history of CV disease (CVD). Prescribed opioid use was defined as opioid use at baseline and/or at the first annual visit (AV1). Cox proportional hazards regression was used to calculate hazard ratios and 95% confidence intervals (95% CI) for associations between opioid use and CVD events following AV1. Of the 17 701 participants included (mean age 75.2 years, 58.2% female), 813 took opioids either at baseline or at AV1. Over a median follow-up period of 3.58 years (IQR 2.50-4.62), CVD events, most notably heart failure hospitalization, occurred in 7% (n = 57) amongst opioid users and 4% (n = 680) amongst non-opioid users. After adjustment for multiple covariates, opiate use was associated with a 1.67-fold (CI 1.26-2.23, P < 0.001) increase in the hazard ratio for CVD events.

CONCLUSIONS

These findings identify opioid use as a non-traditional risk factor for CVD events in community-dwelling older adults.

Novel digital approaches to the assessment of problematic opioid use

The opioid epidemic continues to contribute to loss of life through overdose and significant social and economic burdens. Many individuals who develop problematic opioid use (POU) do so after being exposed to prescribed opioid analgesics. Therefore, it is important to accurately identify and classify risk factors for POU. In this review, we discuss the etiology of POU and highlight novel approaches to identifying its risk factors. These approaches include the application of polygenic risk scores (PRS) and diverse machine learning (ML) algorithms used in tandem with data from electronic health records (EHR), clinical notes, patient demographics, and digital footprints. The implementation and synergy of these types of data and approaches can greatly assist in reducing the incidence of POU and opioid-related mortality by increasing the knowledge base of patient-related risk factors, which can help to improve prescribing practices for opioid analgesics.

Association of obstructive sleep apnea and opioids use on adverse health outcomes: A population study of health administrative data

Rationale

Despite the high prevalence of obstructive sleep apnea (OSA) and concurrent use of opioid therapy, no large-scale population studies have investigated whether opioid use and pre-existing OSA may interact synergistically to increase the risk of adverse health consequences. To address this knowledge gap, we conducted a retrospective cohort study using provincial health administrative data to evaluate whether the combined presence of opioid use and OSA increases the risk of adverse health consequences, such as mortality, hospitalizations, and emergency department (ED) visits; and if it does, whether this co-occurrence has synergistic clinical relevance.

Methods

We included all adults who underwent a diagnostic sleep study in Ontario, Canada, between 2013 and 2016. Individuals were considered exposed to opioids if they filled a prescription that overlapped with the date of their sleep study (Opioid+). Individuals with at least a 50% probability of having a diagnosis of moderate to severe OSA (OSA+) were identified using a previously externally validated case-ascertainment model. The primary outcome was all-cause mortality; secondary outcomes were all-cause or ischemic heart disease hospitalizations, all-cause ED visits, and motor vehicle collisions (MVC) requiring hospital or ED visit. We used multivariable Cox regression models to compare hazards between four mutually exclusive groups: (1) Opioid+ OSA+; (2) Opioid+ OSA-; (3) Opioid- OSA+, and (4) OSA- Opioid- (reference for comparison). Relative excess risks due to interaction (RERI) were calculated to test for additive interaction.

Results

Of 300,663 adults who underwent a sleep study, 15,713 (5.2%) were considered as Opioid+ and 128,351 (42.7%) as OSA+. Over a median of two years, 6,223 (2.1%) died from any cause. Regardless of OSA status, opioid use at the date of the sleep study was associated with an increased hazard for all-cause mortality with the greatest hazard associated with Opioid+ OSA- (adjusted hazard ratio [aHR]: 1.75, 95% CI 1.57–1.94), but not Opioid+ OSA+ (aHR: 1.14, 95% CI 1.02–1.27) as hypothesized. Regardless of OSA status, opioid use at the date of the sleep study was associated with an increased hazard for all secondary outcomes. Opioid+ OSA+ was associated with the greatest hazards of all-cause hospitalizations (aHR 1.55, 95% CI 1.49–1.61) and MVC (aHR of 1.39; 95% CI 1.09–1.77); however, no statistically significant synergistic effects were observed.

Conclusions

Adults referred for sleep disorder assessment who used opioids had a significantly increased hazard of adverse health outcomes than those who did not, regardless of whether they had a high probability of moderate to severe OSA. The use of opioids and OSA was associated with the greatest hazard of all-cause hospitalizations and MVC requiring hospital or ED visit. The interaction of opioids and OSA did not confer a synergistic risk for poor outcomes.

Sleep Deficiency and Opioid Use Disorder: Trajectory, Mechanisms, and Interventions

Opioid use disorder (OUD) is a chronic and relapsing brain disease characterized by loss of control over opioid use and impairments in cognitive function, mood, pain perception, and autonomic activity. Sleep deficiency, a term that encompasses insufficient or disrupted sleep due to multiple potential causes, including sleep disorders (eg, insomnia, sleep apnea), circadian disruption (eg, delayed sleep phase and social jet lag), and poor sleep quality (eg, sleep fragmentation, impaired sleep architecture), is present in greater than 75% of patients with OUD. This article focuses on highlighting bidirectional mechanisms between OUD and sleep deficiency and points toward promising therapeutic targets.

Current and Novel Treatment Options for OSA

Obstructive sleep apnoea is a challenging medical problem due to its prevalence, its impact on quality of life and performance in school and professionally, the implications for risk of accidents, and comorbidities and mortality. Current research has carved out a broad spectrum of clinical phenotypes and defined major pathophysiological components. These findings point to the concept of personalised therapy, oriented on both the distinct clinical presentation and the most relevant pathophysiology in the individual patient. This leads to questions of whether sufficient therapeutic options other than positive airway pressure (PAP) alone are available, for which patients they may be useful, if there are specific indications for single or combined treatment, and whether there is solid scientific evidence for recommendations. This review describes our knowledge on PAP and non-PAP therapies to address upper airway collapsibility, muscle responsiveness, arousability and respiratory drive. The spectrum is broad and heterogeneous, including technical and pharmaceutical options already in clinical use or at an advanced experimental stage. Although there is an obvious need for more research on single or combined therapies, the available data demonstrate the variety of effective options, which should replace the unidirectional focus on PAP therapy.

The analysis of individual pathophysiological composition opens new directions towards personalised treatment of OSA, focusing not only on pharyngeal dilation, but also on technical or pharmaceutical interventions on muscle function or breathing regulationhttps://bit.ly/3sayhkd

Incidence and risk factors of chronic opioid use after sleep apnea surgery

STUDY OBJECTIVES

To assess the incidence and risk factors of chronic opioid use after OSA surgery.

METHODS

Using IBM MarketScan research database, adults (>18) who underwent a variety of sleep surgery procedures between 2007 and 2015, were identified. Subjects with one year of insurance coverage before and after the surgical procedure were included. Additional anesthesia event(s) in the year following the procedure of interest, and those who filled an opioid prescription within the year prior to surgery (not naïve) were excluded. Outcomes included rates of persistent opioid use (additional opioid prescriptions filled 90-180 days postoperatively), prolonged use (additional opioid prescriptions filled 181-365 days postoperatively) and inappropriate use (>100 MME). Evaluated variables include demographics, surgical procedures, and comorbidities.

RESULTS

A total of 10,766 surgical procedures met inclusion criteria. There was a trend of increased rates of perioperative opioid prescription. After multivariable logistic regression analysis, perioperative opioid prescription and smoking were independent risk factors for inappropriate opioid use (OR= 31.51, p<0.001; OR= 1.41, p=0.016 respectively). Opioid prescription and hypertension were independent risk factors for persistent opioid use (OR=37.8, p<0.001, OR=1.38, p=0.008). Perioperative opioid prescription, previous opioid dependence diagnosis, smoking and male gender were associated with continuous prolonged opioid use (OR=73.1, 8.13, 1.95, 1.55, respectively; p<0.001, 0.020, 0.024, 0.032, respectively).

CONCLUSIONS

While efforts by different societies are being implemented to control the opioid crisis, we found that perioperative opioid prescription for airway surgery targeting OSA is an independent risk factor for persistent, prolonged, and inappropriate opioid use.

Less Well-Known Consequences of the Long-Term Use of Opioid Analgesics: A Comprehensive Literature Review

BACKGROUND

The adverse effects of short-term opioid analgesics are well known and acknowledged; however, the spectrum of the sequelae of long-term use seems less clear. Some effects may remain undetected but still have the potential to cause harm and reduce patients' quality of life.

OBJECTIVE

To review the literature on the adverse effects of long-term opioid therapy.

METHODS

We performed a quasi-systematic search, analyzing articles published in the MEDLINE database between January 2000 and March 2021 that identified adverse effects of opioids used for chronic pain treatment.

RESULTS

Growing evidence indicates that there are multiple serious adverse effects of opioid treatment. Long-term opioid use may have significant effects on the endocrine, immune, cardiovascular, respiratory, gastrointestinal, and neural systems. Studies show that long-term opioid treatment increases the risk of fractures, infections, cardiovascular complications, sleep-disordered breathing, bowel dysfunction, overdose, and mortality. Opioids may potentially affect cancer development. Most consequences of the long-term use of opioids have been identified in studies of patients with non-malignant pain.

CONCLUSION

Studies indicate that long-term use of opioids increases the risk of drug-related events in a significant number of patients. Clinicians should be aware of these complications associated with prescribing opioids, discuss them with patients, prevent complications, if possible, and diagnose them early and manage adequately. More human studies are needed to assess the risk, including trials with individual opioids, because they have different adverse effect profiles.

Opioid Therapy in Cancer Patients and Survivors at Risk of Addiction, Misuse or Complex Dependency

A clinical conundrum can occur when a patient with active opioid use disorder (OUD) or at elevated risk for the condition presents with cancer and related painful symptoms. Despite earlier beliefs that cancer patients were relatively unaffected by opioid misuse, it appears that cancer patients have similar risks as the general population for OUD but are more likely to need and take opioids. Treating such patients requires an individualized approach, informed consent, and a shared decision-making model. Tools exist to help stratify patients for risk of OUD. While improved clinician education in pain control is needed, patients too need to be better informed about the risks and benefits of opioids. Patients may fear pain more than OUD, but opioids are not always the most effective pain reliever for a given patient and some patients do not tolerate or want to take opioids. The association of OUD with mental health disorders (dual diagnosis) can also complicate delivery of care as patients with mental health issues may be less adherent to treatment and may use opioids for “chemical coping” as much as for pain control.

Clinical implications of opioid-induced ventilatory impairment

Opioid-induced ventilatory impairment is the primary mechanism of harm from opioid use. Opioids suppress the activity of the central respiratory centres and are sedating, leading to impairment of alveolar ventilation.Respiratory physiological changes induced with acute opioid use include depression of the hypercapnic ventilatory response and hypoxic ventilatory response. In chronic opioid use a compensatory increase in hypoxic ventilatory response maintains ventilation and contributes to the onset of sleep-disordered breathing patterns of central sleep apnoea and ataxic breathing. Supplemental oxygen use in those at risk of opioid-induced ventilatory impairment requires careful consideration by the clinician to prevent failure to detect hypoventilation, if oximetry is being relied on, and the overriding of hypoxic ventilatory drive. Obstructive sleep apnoea and opioid-induced ventilatory impairment are frequently associated, with this interrelationship being complex and often unpredictable. Monitoring the patient for opioid-induced ventilatory impairment poses challenges in the areas of reliability, avoidance of alarm fatigue, cost, and personnel demands. Many situations remain in which patients cannot be provided effective analgesia without opioids, and for these the clinician requires a comprehensive knowledge of opioid-induced ventilatory impairment.

Preoperative apnea-hypopnea index predicts increased postoperative intrathoracic pressure during sleep in patients who underwent endoscopic nasal surgery

OBJECTIVE

Respiratory condition could worsen during sleep in patients with nasal packing following endoscopic nasal and sinus surgery (ESS) under general anesthesia. Recently, a noninvasive intrathoracic pressure estimation sensor was developed that uses photoplethysmographic pulse wave technology. The purpose of this study was to noninvasively evaluate the effect of bilateral nasal packing on respiration during sleep, using a photoplethysmographic pulse wave sensor in perioperative patients who underwent ESS under general anesthesia.

METHODS

In this observational cross-sectional case-control study, estimated intrathoracic pressure and SpO₂ were noninvasively measured during sleep with a wristband-type photoplethysmographic pulse wave sensor and a pulse oximeter in 43 patients with chronic sinusitis, nasal allergy, or septal deviation who underwent bilateral ESS under general anesthesia. Measurements were taken preoperatively, at postoperative day 1 (POD1) with bilateral nasal packing in place, and at POD5 after the nasal packing was removed. Based on the preoperative obstructive apnea-hypopnea index (AHI) score determined by overnight polysomnography, patients were classified into those with moderate to severe obstructive sleep apnea (OSA) (AHI ≥ 15/h) and those with mild or non-OSA (AHI ≤ 15/h).

RESULTS

Significant changes were noted in estimated intrathoracic pressure, but not in SpO₂ nadir, between time points. Estimated intrathoracic pressure decreased the most at POD1 with bilateral nasal packing in place in patients with OSA after ESS. Multivariate stepwise regression revealed the relative incidence of increased estimated intrathoracic pressure on POD1 was independently predicted by preoperative AHI, but not by age, body mass index, total nasal resistance, or preoperative SpO₂ nadir.

CONCLUSION

Use of the photoplethysmographic pulse wave sensor to noninvasively measure intrathoracic pressure detected changes in perioperative respiratory effort that pulse oximetry did not. Attention should be paid to the use of postoperative bilateral nasal packing in patients with moderate to severe OSA who undergo ESS under general anesthesia. Our results support the concept of using less, short-term, or no nasal packing after ESS.

Opioids and obstructive sleep apnea

Opioids are widely prescribed for pain management, and it is estimated that 40% of adults in the United States use prescription opioids every year. Opioid misuse leads to high mortality, with respiratory depression as the main cause of death. Animal and human studies indicate that opioid use may lead to sleep-disordered breathing. Opioids affect control of breathing and impair upper airway function, causing central apneas, upper airway obstruction, and hypoxemia during sleep. The presence of obstructive sleep apnea (OSA) increases the risk of opioid-induced respiratory depression. However, even if the relationship between opioids and central sleep apnea is firmly established, the question of whether opioids can aggravate OSA remains unanswered. While several reports have shown a high prevalence of OSA and nocturnal hypoxemia in patients receiving a high dose of opioids, other studies did not find a correlation between opioid use and obstructive events. These differences can be attributed to considerable interindividual variability, divergent effects of opioids on different phenotypic traits of OSA, and wide-ranging methodology. This review will discuss mechanistic insights into the effects of opioids on the upper airway and hypoglossal motor activity and the association of opioid use and obstructive sleep apnea.

CITATION

Freire C, Sennes LU, Polotsky VY. Opioids and obstructive sleep apnea. J Clin Sleep Med. 2022;18(2):647-652.

The pathophysiology of opioid-induced respiratory depression

Opiates, such as morphine, and synthetic opioids, such as fentanyl, constitute a class of drugs acting on opioid receptors which have been used therapeutically and recreationally for centuries. Opioid drugs have strong analgesic properties and are used to treat moderate to severe pain, but also present side effects including opioid dependence, tolerance, addiction, and respiratory depression, which can lead to lethal overdose if not treated. This chapter explores the pathophysiology, the neural circuits, and the cellular mechanisms underlying opioid-induced respiratory depression and provides a translational perspective of the most recent research. The pathophysiology discussed includes the effects of opioid drugs on the respiratory system in patients, as well as the animal models used to identify underlying mechanisms. Using a combination of gene editing and pharmacology, the neural circuits and molecular pathways mediating neuronal inhibition by opioids are examined. By using pharmacology and neuroscience approaches, new therapies to prevent or reverse respiratory depression by opioid drugs have been identified and are currently being developed. Considering the health and economic burden associated with the current opioid epidemic, innovative research is needed to better understand the side effects of opioid drugs and to discover new therapeutic solutions to reduce the incidence of lethal overdoses.

Closed-loop wearable naloxone injector system

Overdoses from non-medical use of opioids can lead to hypoxemic/hypercarbic respiratory failure, cardiac arrest, and death when left untreated. Opioid toxicity is readily reversed with naloxone, a competitive antagonist that can restore respiration. However, there remains a critical need for technologies to administer naloxone in the event of unwitnessed overdose events. We report a closed-loop wearable injector system that measures respiration and apneic motion associated with an opioid overdose event using a pair of on-body accelerometers, and administers naloxone subcutaneously upon detection of an apnea. Our proof-of-concept system has been evaluated in two environments: (i) an approved supervised injection facility (SIF) where people self-inject opioids under medical supervision and (ii) a hospital environment where we simulate opioid-induced apneas in healthy participants. In the SIF (n = 25), our system identified breathing rate and post-injection respiratory depression accurately when compared to a respiratory belt. In the hospital, our algorithm identified simulated apneic events and successfully injected participants with 1.2 mg of naloxone. Naloxone delivery was verified by intravenous blood draw post-injection for all participants. A closed-loop naloxone injector system has the potential to complement existing evidence-based harm reduction strategies and, in the absence of bystanders, help make opioid toxicity events functionally witnessed and in turn more likely to be successfully resuscitated.

The role of acetazolamide in sleep apnea at sea level: a systematic review and meta-analysis

STUDY OBJECTIVES

The recognition of specific endotypes as drivers of sleep apnea suggests the need of therapies targeting individual mechanisms. Acetazolamide is known to stabilize respiration at high altitude but benefits at sea level are less well understood.

METHODS

All controlled studies of acetazolamide in obstructive sleep apnea and/or central sleep apnea (CSA) were evaluated. The primary outcome was the apnea-hypopnea index.

RESULTS

Fifteen trials with a total of 256 patients were pooled in our systematic review. Acetazolamide reduced the overall apnea-hypopnea index (mean difference [MD] -15.82, 95% CI: -21.91 to -9.74, P < .00001) in central sleep apnea (MD -22.60, 95% CI: -29.11 to -16.09, P < .00001), but not in obstructive sleep apnea (MD -10.29, 95% CI: -33.34 to 12.77, P = .38). Acetazolamide reduced the respiratory related arousal index (MD -0.82, 95% CI: -1.56 to -0.08, P = .03), improved partial arterial of oxygen (MD 11.62, 95% CI: 9.13-14.11, P < .00001), mean oxygen saturation (MD 1.78, 95% CI: 0.53-3.04, P = .005), total sleep time (MD 25.74, 95% CI: 4.10-47.38, P = .02), N2 sleep (MD 3.34, 95% CI: 0.12-6.56, P = .04) and sleep efficiency (MD 4.83, 95% CI: 0.53-9.13, P = .03).

CONCLUSIONS

Acetazolamide improves the apnea-hypopnea index and several sleep metrics in central sleep apnea. The drug may be of clinical benefit in patients with high loop gain apnea of various etiologies and patterns. The existence of high heterogeneity is an important limitation in applicability of our analysis.

SYSTEMATIC REVIEW REGISTRATION

Registry: PROSPERO; Name: The effect of acetazolamide in patients with sleep apnea at sea level: a systematic review and meta analysis; URL: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020163316; Identifier: CRD42020163316.

Treatment for patients with sleep apnea on opioids for chronic pain: results of the OpSafe trial

STUDY OBJECTIVES

Approximately 20% of North Americans are afflicted with chronic pain with 3% being opioid users. The objective was to determine whether patients on opioids for chronic pain with newly diagnosed sleep apnea attended sleep clinic review and followed treatment recommendations.

METHODS

The study was a post hoc analysis from a multicenter perspective cohort study. Inclusion criteria included adults taking opioid medications for chronic pain for >3 months. Demographic data and daily opioid dose were collected. Sleep apnea was diagnosed via level 1 polysomnography. Patients who attended sleep clinic review were grouped based on the types of treatment they received.

RESULTS

A total of 204 patients completed polysomnography and 58.8% were diagnosed to have sleep apnea (apnea-hypopnea index ≥5 events/h). Of those with sleep apnea, 58% were recommended to have an evaluation by a sleep physician. Body mass index and age were 29.5 ± 6 kg/m² and 56 ± 12 years, respectively. Of those with newly diagnosed sleep apnea, 25% received treatment, with the majority being treated with positive airway pressure therapy, whereas the rest received positional therapy and opioids/sedative reduction. The adherence rate of positive airway pressure therapy was 55% at 1 year. Over 50% of participants on opioids for chronic pain with newly diagnosed sleep apnea declined attendance for sleep clinic review or treatment.

CONCLUSIONS

There was a high refusal rate to attend clinic for treatment. Adherence to positive airway pressure therapy was low at 55%. This sheds light on the high rate of treatment nonadherence and the need for further research.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Opioid Safety Program in Pain Clinics (Op-Safe); URL: https://www.clinicaltrials.gov/ct2/show/NCT02513836; Identifier: NCT02513836.

A Pilot Crossover Trial of Sleep Medications for Sleep-disturbed Methadone Maintenance Patients

OBJECTIVES

Problems with sleep are a common and detrimental occurrence among individuals who receive methadone maintenance for opioid use disorder (OUD).

METHODS

We enrolled ten methadone-maintained persons with insomnia (60% female, mean age 40) in a double-blind trial using actigraphy to confirm daily sleep reports. After a no-medication week to establish baseline sleep patterns, each participant received 1 week each of mirtazapine (30 mg), zolpidem (sustained-release 12.5 mg), mirtazapine (30 mg IR) plus zolpidem (10 mg), and placebo, with a washout week between each medication week. Study medication order was randomized so that the order of each 1-week medication treatment was different for each participant, but all participants received all 4 regimens.

RESULTS

We found that mirtazapine alone improved total sleep (mean 23 minutes), sleep latency (mean 23 minutes), and sleep efficiency (mean 3%), surpassing the other regiments.

CONCLUSIONS

This pilot work suggests that mirtazapine is worthy of further testing as a sleep aid for persons with OUD receiving methadone maintenance.

Central Sleep Apnea

Central sleep apnea (CSA) is characterized by intermittent repetitive cessation and/or decreased breathing without effort caused by an abnormal ventilatory drive. Although less prevalent than obstructive sleep apnea, it is frequently encountered. CSA can be primary (idiopathic) or secondary in association with Cheyne-Stokes respiration, drug-induced, medical conditions such as chronic renal failure, or high-altitude periodic breathing. Risk factors have been proposed, including gender, age, heart failure, opioid use, stroke, and other chronic medical conditions. This article discusses the prevalence of CSA in the general population and within each of these at-risk populations, and clinical presentation, diagnostic methods, and treatment.

Chronic Opioid Use and Central Sleep Apnea, Where Are We Now and Where To Go? A State of the Art Review

Opioids are commonly used for pain management, perioperative procedures, and addiction treatment. There is a current opioid epidemic in North America that is paralleled by a marked increase in related deaths. Since 2000, chronic opioid users have been recognized to have significant central sleep apnea (CSA). After heart failure-related Cheyne-Stokes breathing (CSB), opioid-induced CSA is now the second most commonly seen CSA. It occurs in around 24% of chronic opioid users, typically after opioids have been used for more than 2 months, and usually corresponds in magnitude to opioid dose/plasma concentration. Opioid-induced CSA events often mix with episodes of ataxic breathing. The pathophysiology of opioid-induced CSA is based on dysfunction in respiratory rhythm generation and ventilatory chemoreflexes. Opioids have a paradoxical effect on different brain regions, which result in irregular respiratory rhythm. Regarding ventilatory chemoreflexes, chronic opioid use induces hypoxia that appears to stimulate an augmented hypoxic ventilatory response (high loop gain) and cause a narrow CO2 reserve, a combination that promotes respiratory instability. To date, no direct evidence has shown any major clinical consequence from CSA in chronic opioid users. A line of evidence suggested increased morbidity and mortality in overall chronic opioid users. CSA in chronic opioid users is likely to be a compensatory mechanism to avoid opioid injury and is potentially beneficial. The current treatments of CSA in chronic opioid users mainly focus on continuous positive airway pressure (CPAP) and adaptive servo-ventilation (ASV) or adding oxygen. ASV is more effective in reducing CSA events than CPAP. However, a recent ASV trial suggested an increased all-cause and cardiovascular mortality with the removal of CSA/CSB in cardiac failure patients. A major reason could be counteracting of a compensatory mechanism. No similar trial has been conducted for chronic opioid-related CSA. Future studies should focus on (1) investigating the phenotypes and genotypes of opioid-induced CSA that may have different clinical outcomes; (2) determining if CSA in chronic opioid users is beneficial or detrimental; and (3) assessing clinical consequences on different treatment options on opioid-induced CSA.

Associations between obstructive sleep apnea and prescribed opioids among veterans

ABSTRACT

Sleep disruption caused by obstructive sleep apnea (OSA) may be associated with hyperalgesia and may contribute to poor pain control and use of prescription opioids. However, the relationship between OSA and opioid prescription is not well described. We examine this association using cross-sectional data from a national cohort of veterans from recent wars enrolled from October 1, 2001 to October 7, 2014. The primary outcome was the relative risk ratio (RRR) of receiving opioid prescriptions for acute (<90 days/year) and chronic (≥90 days/year) durations compared with no opioid prescriptions. The primary exposure was a diagnosis of OSA. We used multinomial logistic regression to control for factors that may affect diagnosis of OSA or receipt of opioid prescriptions. Of the 1,149,874 patients (mean age 38.0 ± 9.6 years) assessed, 88.1% had no opioid prescriptions, 9.4% had acute prescriptions, and 2.5% had chronic prescriptions. Ten percent had a diagnosis of OSA. Patients with OSA were more likely to be older, male, nonwhite, obese, current or former smokers, have higher pain intensity, and have medical and psychiatric comorbidities. Controlling for these differences, patients with OSA were more likely to receive acute (RRR 2.02 [95% confidence interval 1.98-2.06]) or chronic (RRR 2.15 [2.09-2.22]) opioids. Further dividing opioid categories by high vs low dosage did not yield substantially different results. Obstructive sleep apnea is associated with a two-fold likelihood of being prescribed opioids for pain. Clinicians should consider incorporating OSA treatment into multimodal pain management strategies; OSA as a target for pain management should be further studied.

Predictive Performance of Oximetry to Detect Sleep Apnea in Patients Taking Opioids

BACKGROUND

Long-term use of opioids for treatment of chronic pain is associated with significant risks including worsening unrecognized or untreated sleep apnea that may increase morbidity and mortality. Overnight oximetry has been validated for predicting sleep apnea in surgical and sleep clinic patients. The objective of the study was to assess the predictive accuracy of oxygen desaturation index (ODI 4%) from home overnight oximetry when compared to apnea hypopnea index (AHI) from polysomnography for predicting sleep apnea in patients taking opioids for chronic pain.

METHODS

This was a planned post hoc analysis of a prospective cohort study conducted at 5 pain clinics. Patient characteristics and daily morphine milligram equivalent (MME) dose were recorded. All consented patients underwent home overnight oximetry (PULSOX-300i, Konica Minolta Sensing, Inc, Osaka, Japan) and in-laboratory polysomnography. The predictive performance of ODI 4% from oximetry was assessed against AHI from polysomnography.

RESULTS

Among 332 consented patients, 181 with polysomnography and overnight oximetry data were analyzed. The mean age and body mass index of 181 patients were 52 ± 13 years and 29 ± 6 kg/m2, respectively, with 40% men. The area under the receiver operating curve for ODI to predict moderate-to-severe sleep apnea (AHI ≥15 events/h) and severe sleep apnea (AHI ≥30 events/h) was 0.82 (95% confidence interval [CI], 0.75-0.88) and 0.87 (95% CI, 0.80-0.94). ODI ≥5 events/h had a sensitivity of 85% (95% CI, 74-92) and specificity of 57% (95% CI, 52-61) to predict moderate-to-severe sleep apnea. ODI ≥15 events/h had a sensitivity of 71% (95% CI, 55-83) and specificity of 88% (95% CI, 84-91) to predict severe sleep apnea.

CONCLUSIONS

Overnight home oximetry has a high predictive performance in predicting moderate-to-severe and severe sleep apnea in patients on opioids for chronic pain. It is a useful additional tool for health care providers for the screening of sleep apnea in this high-risk group.