Risk factors for opioid-induced respiratory depression in surgical patients: a systematic review and meta-analyses

Awake Plastic Surgery Procedures: The Use of a Sufentanil Sublingual Tablet to Improve Patient Experience

Background

Awake plastic surgery performed under minimal sedation has advantages including patient preference, affordability, and easier recovery compared to when performed under deeper sedation. Commonly used oral analgesics may not be adequate for awake procedures resulting in moderate to severe pain. Sufentanil sublingual tablet (SST) 30 mcg has been shown to provide timely analgesia with a safety profile appropriate for minimal-sedation settings.

Objectives

To examine perioperative outcomes in patients who underwent awake plastic surgery with local anesthesia and SST 30 mcg for pain control.

Methods

This study was a prospective single-group cohort study conducted at a single plastic surgery center. SST 30 mcg was administered approximately 30 minutes prior to the procedure. Outcome measures included the number of patients with adverse events, the number of patients requiring medications in the post-anesthesia care unit (PACU), and recovery time.

Results

Among the 31 patients, the most common procedures were liposuction (71%), facelift (10%), and blepharoplasty (6%). The mean (± standard error [SE]) procedural duration was 81 ± 9 minutes. No vital sign instability or oxygen desaturation was observed. Three patients (10%) experienced nausea, only one of which required treatment with oral ondansetron 4 mg in the PACU. One patient (3%) experienced dizziness that did not require treatment. No patients required opioids or other analgesics in the PACU for pain. The mean (±SE) recovery time was 15 ± 4 minutes.

Conclusions

Awake plastic surgery can be performed using SST 30 mcg with minimal side effects and a rapid recovery time.

Level of Evidence: 4

Intraoperatively local infiltration anesthesia in hemiarthroplasty patients reduces the needs of opioids: a randomized, double-blind, placebo-controlled trial with 96 patients in a fast-track hip fracture setting

Background and purpose - Local infiltration analgesia (LIA) is commonly used as a component in multimodal analgesia. Pain management directed towards hip fracture patients operated on with hemiarthroplasty is often based on knowledge regarding pain treatment following elective surgery. In this elderly patient population, it is of value to clarify whether adding local infiltration analgesia (LIA) to the postoperative analgesic regimen might reduce postoperative pain or have an opioid-reducing effect. Patients and methods - 96 hip fracture patients undergoing hemiarthroplasty in spinal anesthesia were included. All patients received a multimodal pain regimen and were randomized to receive either ropivacaine or placebo. All patients received morphine depot-opioid and morphine as rescue medication postoperatively. The primary endpoint was pain during mobilization in the recovery unit on the day of surgery. Secondary endpoints were pain during mobilization the day after surgery and postoperative opioid requirements on the first postoperative day. Results - The levels of pain (NRS) during mobilization both in the recovery unit and on the day after surgery were similar in the 2 groups, with median 4 and 0.5 in the placebo group and median 3.5 and 1 in the ropivacaine group respectively. Total consumption of opioids on day 0 and day 1 were 4.6 mg lower in the ropivacaine group (p = 0.04). Pain during mobilization was registered for only 44 of 96 patients for several reasons, including lack of mobilization. Interpretation - There were similar pain scores in both the local infiltration and placebo group postoperatively. However, substantially reduced opioid consumption was found in patients receiving LIA.

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.

Oliceridine- Opioid of the 21st Century

Oliceridine (Olinvyk® Trevena, PA, USA) was approved by the United States Food and Drug Administration for clinical use on Aug 8, 2020. Even though, the indication of its approval is very restrictive (to manage moderate-to-severe acute pain in adults when the pain is severe enough), for such an innovative opioid, off-label indications are bound to abound. What could be described as the "opioid of the century," it aims to overcome some of the stubbornest barriers to opioid prescribing, namely addiction liability, respiratory depression, and gastrointestinal (GI) side effects, just to name a few. The novel opioid accomplishes this by a unique mechanism of action. By selectively acting on the G-protein sub-pathway in preference to the beta-arrestin, it aims to mitigate these unwanted µ-opioid receptors-associated opioid side effects, while preserving its analgesic activity. What remains to be seen, however, is if these observations seen in phases 2 and 3 trials will be borne in actual large-scale clinical use, both inside and outside the USA. Unfortunately, the field of anesthesia is rife with innovations that have shown enormous promise at the research stage, only to end up as damp squibs when released to the clinicians for general use. Rapcuronium and althesin are some such examples. We aim to present some of the contentious and emerging issues associated with this drug and some of the potential pitfalls of this new opioid.

Prevention of Acute Postoperative Pain in Breast Cancer: A Comparison between Opioids versus Ketamine in the Intraoperatory Analgesia

Background

Acute postoperative pain (APP) has a high incidence in breast surgery, and opioids are the most commonly used drugs for its management; however, they are not free from systemic side effects, which may increase comorbidity. In the past few years, opioid-free anaesthesia has been favoured with promising results.

Methods

We conducted a descriptive study including 71 patients who underwent breast cancer surgery. The opioid group (n = 41) received fentanyl for induction, remifentanil for maintenance, and rescue morphine before waking up, whereas the ketamine group (n = 30) received a ketamine bolus for induction followed by continuous ketamine infusion during surgery. Later, the presence and intensity of pain were registered, using the Numeric Rating Scale (NRS 1-10) for pain, at different times in the recovery room, at 24 hours and at 3 months.

Results

Administration of ketamine is more effective than opioid use for APP prevention in breast cancer surgery because the ketamine group presented with less pain than the opioid group (p < 0.05) at all measured times. When there was pain, patients in the ketamine group gave a lower score to its intensity (p < 0.05).

Conclusions

Ketamine could reduce the incidence of APP in breast cancer surgery, compared to opioids.

Predicting opioid-induced oversedation in hospitalised patients: a multicentre observational study

OBJECTIVES

Opioid-induced respiratory depression (OIRD) and oversedation are rare but potentially devastating adverse events in hospitalised patients. We investigated which features predict an individual patient's risk of OIRD or oversedation; and developed a risk stratification tool that can be used to aid point-of-care clinical decision-making.

DESIGN

Retrospective observational study.

SETTING

Twelve acute care hospitals in a large not-for-profit integrated delivery system.

PARTICIPANTS

All inpatients ≥18 years admitted between 1 July 2016 and 30 June 2018 who received an opioid during their stay (163 190 unique hospitalisations).

MAIN OUTCOME MEASURES

The primary outcome was occurrence of sedation or respiratory depression severe enough that emergent reversal with naloxone was required, as determined from medical record review; if naloxone reversal was unsuccessful or if there was no evidence of hypoxic encephalopathy or death due to oversedation, it was not considered an oversedation event.

RESULTS

Age, sex, body mass index, chronic obstructive pulmonary disease, concurrent sedating medication, renal insufficiency, liver insufficiency, opioid naïvety, sleep apnoea and surgery were significantly associated with risk of oversedation. The strongest predictor was concurrent administration of another sedating medication (adjusted HR, 95% CI=3.88, 2.48 to 6.06); the most common such medications were benzodiazepines (29%), antidepressants (22%) and gamma-aminobutyric acid analogue (14.7%). The c-statistic for the final model was 0.755. The 24-point Oversedation Risk Criteria (ORC) score developed from the model stratifies patients as high (>20%, ≥21 points), moderate (11%-20%, 10-20 points) and low risk (≤10%, <10 points).

CONCLUSIONS

The ORC risk score identifies patients at high risk for OIRD or oversedation from routinely collected data, enabling targeted monitoring for early detection and intervention. It can also be applied to preventive strategies-for example, clinical decision support offered when concurrent prescriptions for opioids and other sedating medications are entered that shows how the chosen combination impacts the patient's risk.

Postpartum Respiratory Depression

Postpartum respiratory depression is a complex, multifactorial issue that encompasses a patient's baseline preexisting conditions, certain pregnancy-specific conditions or complications, as well as the iatrogenic element of various medications given in the peripartum period. In this review, we discuss many of these factors including obesity, sleep-disordered breathing, chronic lung disease, neuromuscular disorders, opioids, preeclampsia, peripartum cardiomyopathy, postpartum hemorrhage, amniotic fluid embolism, sepsis, acute respiratory distress syndrome (ARDS), and medications such as analgesics, sedatives, anesthetics, and magnesium. Current recommendations for screening, treatment, and prevention are also discussed.

Healthcare resource utilisation and cost analysis associated with opioid analgesic use for non-cancer pain: A case-control, retrospective study between 2005 and 2015

Objective

To examine differences in healthcare utilisation and costs associated with opioid prescriptions for non-cancer pain issued in primary care.

Method

A longitudinal, case-control study retrospectively examined Welsh healthcare data for the period 1 January 2005–31 December 2015. Data were extracted from the Secure Anonymised Information Linkage (SAIL) databank. Subjects, aged 18 years and over, were included if their primary care record contained at least one of six overarching pain diagnoses during the study period. Subjects were excluded if their record also contained a cancer diagnosis in that time or the year prior to the study period. Case subjects also received at least one prescription for an opioid analgesic. Controls were matched by gender, age, pain-diagnosis and socioeconomic deprivation. Healthcare use included primary care visits, emergency department (ED) and outpatient (OPD) attendances, inpatient (IP) admissions and length of stay. Cost analysis for healthcare utilisation used nationally derived unit costs for 2015. Differences between case and control subjects for resource use and costs were analysed and further stratified by gender, prescribing persistence (PP) and deprivation.

Results

Data from 3,286,215 individuals were examined with 657,243 receiving opioids. Case subjects averaged 5 times more primary care visits, 2.8 times more OPD attendances, 3 times more ED visits and twice as many IN admissions as controls. Prescription persistence over 6 months and greater deprivation were associated with significantly greater utilisation of healthcare resources. Opioid prescribing was associated with 69% greater average healthcare costs than in control subjects. National Health Service (NHS) healthcare service costs for people with common, pain-associated diagnoses, receiving opioid analgesics were estimated to be £0.9billion per year between 2005 and 2015.

Conclusion

Receipt of opioid prescriptions was associated with significantly greater healthcare utilisation and accompanying costs in all sectors. Extended prescribing durations are particularly important to address and should be considered at the point of initiation.

Nurses' Ability to Recognize and Prevent Opioid-Induced Respiratory Depression: An Evidenced-Based Practice Project

Opioids are the primary therapy for acute postoperative pain, despite being associated with opioid-induced respiratory depression (OIRD). The purpose of this study was to improve nurses' knowledge, confidence, and ability to recognize, prevent, and treat OIRD in postoperative inpatients and evaluate the feasibility of using the Pasero Opioid-Induced Sedation Scale (POSS). Registered nurses completed three tools: (1) an Opioid Knowledge Self-Assessment, which was administered pre- and post-education; (2) a Confidence Scale, which was administered pre- and post-education; and (3) a POSS Perceptions and Usability Scale that was administered post-education. Nurses were educated on the POSS and then immediately following the training practiced by undertaking a patient assessment using the instrument. They then completed the POSS Perceptions and Usability Scale to rate their perception of the feasibility of using the POSS. Between preeducation and posteducation, participant knowledge increased in the following areas: recognizing opioid-induced side effects, dose selection, risk factors for oversedation, and information to make clinical decisions. However, there was a drop in scores when asked about knowledge of who is at risk for opioid-related side effects. These findings support our conclusion that OIRD education improves nursing confidence and knowledge. There was significant agreement between the nurse and subject matter experts POSS scores, indicating that this tool is easy to use.

INCIDENCE AND OUTCOMES OF LIFE-THREATENING EVENTS DURING HOSPITALIZATION: A RETROSPECTIVE STUDY OF PATIENTS TREATED WITH NALOXONE

BACKGROUND

We describe the clinical course of medical and surgical patients who received naloxone on general hospital wards for suspected opioid induced respiratory depression (OIRD).

METHODS

From May 2018 through October 2020, patients who received naloxone on hospital wards were identified and records reviewed for incidence and clinical course.

RESULTS

There were 86,030 medical and 106,807 surgical admissions. Naloxone was administered to 99 (incidence 11.5 [95%CI 9.4-14.0] per 10,000 admissions) medical and 63 (5.9 [95%CI 4.5-7.5]) surgical patients, P < 0.001. Median oral morphine equivalents administered within 24-hour before naloxone was 32 [15, 64] and 60 [32, 88] mg for medical and surgical patients, respectively, P = 0.002. Rapid response team was activated in 69 (69.7%) vs. 42 (66.7%) and critical care transfers in 51 (51.5%) vs. 30 (47.6%) medical and surgical patients respectively. In-hospital mortality was 21 (21.2%) vs. 2 (3.2%) and discharge to hospice 12 (12.1%) vs. 1 (1.6%), for medical and surgical patients respectively, P = 0.001. Naloxone did not reverse OIRD in 38 (23%) patients, and these patients had more transfers to the intensive care unit and 30-day mortality.

CONCLUSION

Medical inpatients are more likely to suffer OIRD than surgical inpatients despite lower opioid dose. Definitive OIRD was confirmed in 77% of patients because immediate naloxone response, while 23% of patients did not respond and this subset were more likely to need higher level of care and had higher 30-day mortality. Careful monitoring of mental and respiratory variables is necessary when opiates are used in hospital.

Multi-Level Regulation of Opioid-Induced Respiratory Depression

Opioids depress minute ventilation primarily by reducing respiratory rate. This results from direct effects on the preBötzinger Complex as well as from depression of the Parabrachial/Kölliker-Fuse Complex, which provides excitatory drive to preBötzinger Complex neurons mediating respiratory phase-switch. Opioids also depress awake drive from the forebrain and chemodrive.

Safety evaluation of oliceridine for the management of postoperative moderate-to-severe acute pain

INTRODUCTION

Opioids for managing postoperative pain are associated with side effects including opioid-induced respiratory depression (OIRD) and gastrointestinal complications. Opioids induce analgesia via G-protein signaling, while adverse effects are mediated by the β-arrestin pathway. Oliceridine is a biased ligand that preferentially activates G-protein signaling over β-arrestin, theoretically reducing adverse effects. Oliceridine has been approved by the Food and Drug Administration to treat acute pain severe enough to require intravenous opioid analgesics.

AREAS COVERED

Preclinical and clinical trials demonstrate the analgesic efficacy of oliceridine. Available evidence suggests that oliceridine may have a lower risk of OIRD and gastrointestinal complications compared to conventional opioids.

EXPERT OPINION

The analgesic efficacy of oliceridine has been evaluated in several clinical trials. However, safety data were obtained from an open-label observational study and studies assessing adverse effects as secondary outcomes, as post-hoc analyses, or from retrospective studies. These may be affected by gaps in detecting adverse events, heterogeneity in the original studies, and the limitations of retrospective studies. Prospective trials examining the safety of oliceridine versus conventional opioids are needed. Studies are also needed to assess the safety and efficacy of oliceridine in obstetric and pediatric populations, and in the context of multimodal analgesia and Enhanced Recovery after Surgery protocols.

Opioid analgesic use after ambulatory surgery: a descriptive prospective cohort study of factors associated with quantities prescribed and consumed

OBJECTIVES

To prospectively characterise: (1) postoperative opioid analgesic prescribing practices; (2) experience of patients undergoing elective ambulatory surgeries and (3) impact of patient risk for medication misuse on postoperative pain management.

DESIGN

Longitudinal survey of patients 7 days before and 7-14 days after surgery.

SETTING

Academic urban safety-net hospital.

PARTICIPANTS

181 participants recruited, 18 surgeons, follow-up data from 149 participants (82% retention); 54% women; mean age: 49 years.

INTERVENTIONS

None.

PRIMARY AND SECONDARY OUTCOME MEASURES

Total morphine equivalent dose (MED) prescribed and consumed, percentage of unused opioids.

RESULTS

Surgeons postoperatively prescribed a mean of 242 total MED per patient, equivalent to 32 oxycodone (5 mg) pills. Participants used a mean of 116 MEDs (48%), equivalent to 18 oxycodone (5 mg) pills (~145 mg of oxycodone remaining per patient). A 10-year increase in patient age was associated with 12 (95% CI (-2.05 to -0.35)) total MED fewer prescribed opioids. Each one-point increase in the preoperative Graded Chronic Pain Scale was associated with an 18 (6.84 to 29.60) total MED increase in opioid consumption, and 5% (-0.09% to -0.005%) fewer unused opioids. Prior opioid prescription was associated with a 55 (5.38 to -104.82) total MED increase in opioid consumption, and 19% (-0.35% to -0.02%) fewer unused opioids. High-risk drug use was associated with 9% (-0.19% to 0.002%) fewer unused opioids. Pain severity in previous 3 months, high-risk alcohol, use and prior opioid prescription were not associated with postoperative prescribing practices.

CONCLUSIONS

Participants with a preoperative history of chronic pain, prior opioid prescription, and high-risk drug use were more likely to consume higher amounts of opioid medications postoperatively. Additionally, surgeons did not incorporate key patient-level factors (eg, substance use, preoperative pain) into opioid prescribing practices. Opportunities to improve postoperative opioid prescribing include system changes among surgical specialties, and patient education and monitoring.

Evaluation of Noninvasive Respiratory Volume Monitoring in the PACU of a Low Resource Kenyan Hospital

This research aims to evaluate the use of the noninvasive respiratory volume monitor (RVM) compared to the standard of care (SOC) in the Post-Anesthesia Care Unit (PACU) of Kijabe Hospital, Kenya. The RVM provides real-time measurements for quantitative monitoring of non-intubated patients. Our evaluation was focused on the incidence of postoperative opioid-induced respiratory depression (OIRD). The RVM cohort (N = 50) received quantitative OIRD assessment via the RVM, which included respiratory rate, minute ventilation, and tidal volume. The SOC cohort (N = 46) received qualitative OIRD assessment via patient monitoring with oxygenation measurements (SpO₂) and physical examination. All diagnosed cases of OIRD were in the RVM cohort (9/50). In the RVM cohort, participants stayed longer in the PACU and required more frequent airway maneuvers and supplemental oxygen, compared to SOC (all p < 0.05). The SOC cohort may have had fewer diagnoses of OIRD due to the challenging task of distinguishing hypoventilation versus OIRD in the absence of quantitative data. To account for the higher OIRD risk with general anesthesia (GA), a subgroup analysis was performed for only participants who underwent GA, which showed similar results. The use of RVM for respiratory monitoring of OIRD may allow for more proactive care.

Low Incidence of Opioid-Induced Respiratory Depression Observed with Oliceridine Regardless of Age or Body Mass Index: Exploratory Analysis from a Phase 3 Open-Label Trial in Postsurgical Pain

INTRODUCTION

Advanced age and obesity are reported to increase the risk of opioid-induced respiratory depression (OIRD). Oliceridine, an intravenous opioid, is a G-protein-biased agonist at the µ-opioid receptor that may provide improved safety. The recent phase 3 ATHENA open-label, multicenter study evaluated postoperative use of oliceridine in patients with moderate-to-severe acute pain. This exploratory analysis of the ATHENA data examined the incidence of OIRD in older (≥ 65 years) and/or obese (BMI ≥ 30 kg/m2) patients and analyzed risk factors of OIRD.

METHODS

Patients aged ≥ 18 years with a score ≥ 4 on an 11-point numeric pain rating scale (NPRS) received IV oliceridine as needed via bolus dosing and/or patient-controlled analgesia (PCA). OIRD occurring within 48 h of last dose of oliceridine was defined using two established definitions: (1) naloxone use, (2) respiratory rate < 10 breaths per minute and/or oxygen saturation < 90%.

RESULTS

A total of 724 surgical patients with a mean age of 54.5 ± 15.9 years and a mean NRS score of 6.2 ± 2.1 were included in this analysis; 33.3% (241/724) were ≥ 65 years of age and 46.3% (335/724) had BMI (body mass index) ≥ 30 kg/m2. The overall OIRD incidence was 13.7% with no patients requiring naloxone. The OIRD incidence was similar in the elderly and younger adults' cohorts [10.8 vs. 15.1%, OR 0.68 (0.42, 1.1), p = 0.11], and in obese and non-obese groups [14.0 vs. 13.4%, OR 1.06 (0.69, 1.62), p = 0.80]. In patients that were both elderly and obese (n = 120), the incidence was 10.8%. The multivariate analysis identified baseline NRS ≥ 6 [OR 1.6 (1.0, 2.4), p = 0.0499], PCA administration [OR 1.9 (1.2, 3.1), p = 0.005], and concomitant use of benzodiazepines and/or gabapentinoids [OR 1.6 (1.0, 2.6), p = 0.045], as being associated with OIRD.

CONCLUSIONS

Postoperative oliceridine use in patients with advanced age and/or increased BMI was not associated with increased risk of OIRD.

Perioperative Management of the Patient With Obstructive Sleep Apnea: A Narrative Review

The prevalence of obstructive sleep apnea (OSA) has reached 1 billion people worldwide, implying significant risk for the perioperative setting as patients are vulnerable to cardiopulmonary complications, critical care requirement, and unexpected death. This review summarizes main aspects and considerations for the perioperative management of OSA, a condition of public health concern. Critical determinants of perioperative risk include OSA-related changes in upper airway anatomy with augmented collapsibility, diminished capability of upper airway dilator muscles to respond to airway obstruction, disparities in hypoxemia and hypercarbia arousal thresholds, and instability of ventilatory control. Preoperative OSA screening to identify patients at increased risk has therefore been implemented in many institutions. Experts recommend that in the absence of severe symptoms or additional compounding health risks, patients may nevertheless proceed to surgery, while heightened awareness and the adjustment of postoperative care is required. Perioperative caregivers should anticipate difficult airway management in OSA and be prepared for airway complications. Anesthetic and sedative drug agents worsen upper airway collapsibility and depress central respiratory activity, while the risk for postoperative respiratory compromise is further increased with the utilization of neuromuscular blockade. Consistently, opioid analgesia has proven to be complex in OSA, as patients are particularly prone to opioid-induced respiratory depression. Moreover, basic features of OSA, including intermittent hypoxemia and repetitive sleep fragmentation, gradually precipitate a higher sensitivity to opioid analgesic potency along with an increased perception of pain. Hence, regional anesthesia by blockade of neural pathways directly at the site of surgical trauma as well as multimodal analgesia by facilitating additive and synergistic analgesic effects are both strongly supported in the literature as interventions that may reduce perioperative complication risk. Health care institutions are increasingly allocating resources, including those of postoperative enhanced monitoring, in an effort to increase patient safety. The implementation of evidence-based perioperative management strategies is however burdened by the rising prevalence of OSA, the large heterogeneity in disease severity, and the lack of evidence on the efficacy of costly perioperative measures. Screening and monitoring algorithms, as well as reliable risk predictors, are urgently needed to identify OSA patients that are truly in need of extended postoperative surveillance and care. The perioperative community is therefore challenged to develop feasible pathways and measures that can confer increased patient safety and prevent complications in patients with OSA.

Pharmacologically Induced Ventilatory Depression in the Postoperative Patient: A Sleep-Wake State-Dependent Perspective

Pharmacologically induced ventilatory depression (PIVD) is a common postoperative complication with a spectrum of severity ranging from mild hypoventilation to severe ventilatory depression, potentially leading to anoxic brain injury and death. Recent studies, using continuous monitoring technologies, have revealed alarming rates of previously undetected severe episodes of postoperative ventilatory depression, rendering the recognition of such episodes by the standard intermittent assessment practice, quite problematic. This imprecise description of the epidemiologic landscape of PIVD has thus stymied efforts to understand better its pathophysiology and quantify relevant risk factors for this postoperative complication. The residual effects of various perianesthetic agents on ventilatory control, as well as the multiple interactions of these drugs with patient-related factors and phenotypes, make postoperative recovery of ventilation after surgery and anesthesia a highly complex physiological event. The sleep-wake, state-dependent variation in the control of ventilation seems to play a central role in the mechanisms potentially enhancing the risk for PIVD. Herein, we discuss emerging evidence regarding the epidemiology, risk factors, and potential mechanisms of PIVD.

Opioid-Induced In-Hospital Deaths: A 10-Year Review of Australian Coroners' Cases Exploring Similarities and Lessons Learnt

Although opioids are the cornerstone of moderate-to-severe acute pain management they are appropriately recognised as high-risk medicines. Patient and health service delivery factors can contribute to an increased risk of death associated with excessive sedation and respiratory impairment. Despite increasing awareness of opioid-induced ventilation impairment (OIVI), no reliable method consistently identifies individual characteristics and factors that increase mortality risk due to respiratory depression events. This study assessed similarities in available coronial inquest cases reviewing opioid-related deaths in Australian hospitals from 2010 to 2020. Cases included for review were in-hospital deaths that identified patient factors, clinical errors and service delivery factors that resulted in opioid therapy contributing to the death. Of the 2879 coroner’s inquest reports reviewed across six Australian states, 15 met the criteria for inclusion. Coroner’s inquest reports were analysed qualitatively to identify common themes, contributing patient and service delivery factors and recommendations. Descriptive statistics were used to summarise shared features between cases. All cases included had at least one, but often more, service delivery factors contributing to the death, including insufficient observations, prescribing/administration error, poor escalation and reduced communication. Wider awareness of the individual characteristics that pose increased risk of OIVI, greater uptake of formal, evidence-based pain management guidelines and improved documentation and observations may reduce OIVI mortality rates.

Oliceridine: A Novel Drug for the Management of Moderate to Severe Acute Pain - A Review of Current Evidence

Optimal pain relief requires a balance between adequate analgesia and risk of adverse effects. Opioids remain the cornerstone for managing moderate to severe pain, but are associated with opioid-induced respiratory depression (OIRD) and gastrointestinal complications. Opioids exert their analgesic effects predominantly via G-protein signaling, however, adverse effects including OIRD are mediated by the β-arrestin pathway. Oliceridine is the first of a new class of biased opioid agonists that preferentially activate G-protein signaling over β-arrestin, which would theoretically improve analgesia and reduce the risk of adverse effects. Oliceridine is approved by the Food and Drug Administration (FDA) for the treatment of moderate to severe acute pain. The efficacy of Oliceridine was mainly established in two randomized controlled Phase III clinical trials of patients experiencing moderate to severe pain after bunionectomy (APOLLO-1) and abdominoplasty (APOLLO-2). The results of the APOLLO studies demonstrate that Oliceridine, when administered via patient-controlled analgesia (PCA) demand boluses of 0.35mg and 0.5mg, provides superior analgesia compared to placebo, and is equianalgesic to PCA morphine 1mg demand boluses, without significant difference in the incidence of respiratory complications. In a more pragmatic trial of surgical and non-surgical patients, the ATHENA observational cohort study reported rapid onset of analgesia with Oliceridine given with or without multimodal analgesia. However, these studies were designed to evaluate analgesic efficacy, and it is still uncertain if Oliceridine has a better safety profile than conventional opioids. Although several post hoc analyses of pooled data from the APOLLO and ATHENA trials reported that Oliceridine was associated with lower OIRD and gastrointestinal complications compared to morphine, prospective studies are needed to elucidate if biased agonists such as Oliceridine reduce the risk of adverse effects compared to conventional opioids.

Opioid-induced respiratory depression increases hospital costs and length of stay in patients recovering on the general care floor

BACKGROUND

Opioid-induced respiratory depression is common on the general care floor. However, the clinical and economic burden of respiratory depression is not well-described. The PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY (PRODIGY) trial created a prediction tool to identify patients at risk of respiratory depression. The purpose of this retrospective sub-analysis was to examine healthcare utilization and hospital cost associated with respiratory depression.

METHODS

One thousand three hundred thirty-five patients (N = 769 United States patients) enrolled in the PRODIGY trial received parenteral opioids and underwent continuous capnography and pulse oximetry monitoring. Cost data was retrospectively collected for 420 United States patients. Differences in healthcare utilization and costs between patients with and without ≥1 respiratory depression episode were determined. The impact of respiratory depression on hospital cost per patient was evaluated using a propensity weighted generalized linear model.

RESULTS

Patients with ≥1 respiratory depression episode had a longer length of stay (6.4 ± 7.8 days vs 5.0 ± 4.3 days, p = 0.009) and higher hospital cost ($21,892 ± $11,540 vs $18,206 ± $10,864, p = 0.002) compared to patients without respiratory depression. Patients at high risk for respiratory depression, determined using the PRODIGY risk prediction tool, who had ≥1 respiratory depression episode had higher hospital costs compared to high risk patients without respiratory depression ($21,948 ± $9128 vs $18,474 ± $9767, p = 0.0495). Propensity weighted analysis identified 17% higher costs for patients with ≥1 respiratory depression episode (p = 0.007). Length of stay significantly increased total cost, with cost increasing exponentially for patients with ≥1 respiratory depression episode as length of stay increased.

CONCLUSIONS

Respiratory depression on the general care floor is associated with a significantly longer length of stay and increased hospital costs. Early identification of patients at risk for respiratory depression, along with early proactive intervention, may reduce the incidence of respiratory depression and its associated clinical and economic burden.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT02811302 .

INFLUENCE OF DIFFERENT TYPES OF ANESTHESIA FOR LAPAROSCOPIC HYSTERECTOMY ON THE DYNAMICS OF STRESS HORMONES

The aim of the study – to evaluate the influence of different variants of anesthesia, including low-opioid (LOA) and opioid-free anesthesia (OFA), on the dynamics of the stress response during laparoscopic hysterectomy. Materials and methods: 102 patients were randomly allocated into 3 groups: 37 women assigned to receive a standard opioid-based anesthesia (OBA group), 33 women – LOA group and 32 patients OFA group. Results: The patients of OFA group after induction and intubation of the trachea showed a significant (p<0.05) increase in cortisol level by 155.4 % and 160.9 % compared with the OBA group and LOA group. After completion of the hysterectomy, regardless of the variant of anesthesia, the level of cortisol exceeded the preoperative one (pOBA=0.116, pLOA=0.049, pOFA=0.043). Two hours after surgery with standard anesthesia (OBA group) there was a further increase in the concentration of cortisol in the blood, exceeding the initial values by 142.9 % (p=0.043). Patients in the LOA group and OFA group tended to decrease cortisolemia. The changes in adrenaline & glucose levels were somewhat similar. Conclusion: Use of OFA is accompanied by an aggravation of the stress response at the stage of hysterectomy, which is manifested by an increase in the level of adrenaline and cortisol. The most adequate perioperative protection is inherent in low-opioid anesthesia, which is accompanied by a lower release of stress hormones during hysterectomy and in the postoperative period. Opioid-based anesthesia provides adequate intraoperative protection, but is accompanied by insufficient postoperative analgesia.

Postoperative opioid administration characteristics associated with opioid-induced respiratory depression: Results from the PRODIGY trial

STUDY OBJECTIVE

Opioid administration for pain in general care floor patients remains common, and can lead to adverse outcomes, including respiratory compromise. The PRODIGY trial found that among ward patients receiving parenteral opioids, 46% experienced ≥1 respiratory depression episode. The objective of this analysis was to evaluate the geographic differences of opioid administration and examine the association between opioid administration characteristics and the occurrence of respiratory depression.

DESIGN

Prospective observational trial.

SETTING

16 general care medical and surgical wards in Asia, Europe, and the United States.

PATIENTS

1335 patients receiving parenteral opioids.

INTERVENTIONS

Blinded, alarm-silenced continuous capnography and pulse oximetry monitoring.

MEASUREMENTS

Opioid-induced respiratory depression, defined as respiratory rate ≤ 5 bpm, SpO₂ ≤ 85%, or ETCO₂ ≤ 15 or ≥ 60 mmHg for ≥3 min; apnea episode lasting >30 s; or any respiratory opioid-related adverse event.

RESULTS

Across all patients, 58% received only long-acting opioids, 16% received only short-acting (<3 h) opioids, and 21% received a combination of short- and long-acting (≥3 h) opioids. The type and median total morphine milligram equivalent (MME) of opioid administered varied significantly by region, with 31.5 (12.5-76.7) MME, 31.0 (6.2-99.0) MME, and 7.2 (1.7-18.7) MME in the United States, Europe, and Asia, respectively (p < 0.001). Considering only postoperative opioids, 54% (N = 119/220) and 45% (N = 347/779) of patients receiving only short-acting opioids or only long-acting opioids experienced ≥1 episode of opioid-induced respiratory depression, respectively. Multivariable analysis identified post-procedure tramadol (OR 0.62, 95% CI 0.424-0.905, p = 0.0133) and post-procedure epidural opioids (OR 0.485, 95% CI 0.322-0.731, p = 0.0005) being associated with a significant reduction in opioid-induced respiratory depression.

CONCLUSIONS

Despite varying opioid administration characteristics between Asia, Europe, and the United States, opioid-induced respiratory depression remains a common global problem on general care medical and surgical wards. While the use of post-procedure tramadol or post-procedure epidural opioids may reduce the incidence of respiratory depression, continuous monitoring is also necessary to ensure patient safety when receiving postoperative opioids. REGISTRATION NUMBER: www.clinicaltrials.gov, ID: NCT02811302.

The relationship between opioid use and obstructive sleep apnea: A systematic review and meta-analysis

We conducted a systematic review to address limited evidence suggesting that opioids may induce or aggravate obstructive sleep apnea (OSA). All clinical trials or observational studies on adults from 1946 to 2018 found through MEDLINE, EMBASE, CINAHL, PsycINFO, Cochrane Databases were eligible. We assessed the quality of the studies using published guidelines. Fifteen studies (six clinical trials and nine observational) with only two of good quality were included. Fourteen studies investigated the impact of opioids on the presence or severity of OSA, four addressed the effects of treatment for OSA  in opioid users, and none explored the consequences of opioid use in individuals with OSA. Eight of 14 studies found no significant relationship between opioid use or dose and apnea-hypopnea index (AHI) or degree of nocturnal desaturation. A random-effects meta-analysis (n = 10) determined the pooled mean change in AHI associated with opioid use of 1.47/h (-2.63-5.57; I² = 65%). Three of the four studies found that continuous positive airway pressure (CPAP) therapy reduced AHI by 17-30/h in opioid users with OSA. Bilevel therapy with a back-up rate and adaptive servo-ventilation (ASV) without mandatory pressure support successfully normalized AHI (≤5) in opioid users. Limited by a paucity of good-quality studies, our review did not show a significant relationship between opioid use and the severity of OSA. There was some evidence that CPAP, Bilevel therapy, and ASV alleviate OSA for opioid users, with higher failure rates observed in patients on CPAP in opioid users.

Prevalence, predictors and trends of opioid prescribing for lower back pain in United States emergency departments

WHAT IS KNOWN AND OBJECTIVE

Current evidence-based guidelines for the treatment of acute low back pain (ALBP) recommend the use of opioid medications only after failure of nonpharmacological therapy, non-steroidal anti-inflammatory drugs and skeletal muscle relaxants and after thorough evaluation of risks and benefits. Despite this recommendation and the state of the opioid epidemic in the United States (US), opioids remain a common drug of choice for ALBP in the emergency department (ED). The purpose of this study was to quantify the prevalence and identify predictors of opioid prescribing for acute lower back pain (ALBP) in emergency departments (EDs) in the United States.

METHODS

This was a national, cross-sectional study of the National Hospital Ambulatory Care Survey from 2013-2016. ED visits for patients aged ≥18 years treated for ALBP were included. Patients presenting with specified reasons that an opioid may be indicated were excluded. The primary endpoint was frequency of opioids prescribed. A multivariate logistic regression model identified patient- and provider-level predictors of opioid use.

RESULTS AND DISCUSSION

This analysis included 2260 visits for ALBP. Opioids were prescribed in 32.3% of visits. Positive predictors of opioid prescribing were pain score of 7-10 (OR 1.85; 95% CI 1.26-2.70), and patients seen in the Southern (OR 2.53; 95% CI 1.47-4.36) or Western US (OR 2.10; 95% CI 1.19-3.70). Opioids were prescribed less often to patients who received a NSAID or acetaminophen (OR 0.38; 95% CI 0.28-0.52 and OR 0.03; 95% CI 0.01-0.10, respectively).

WHAT IS NEW AND CONCLUSION

Opioid prescribing rates for ALBP remain high and the predictors identified demonstrate that this prescribing pattern is not uniformly distributed across the patient and provider characteristics studied.

Low Incidence of Postoperative Respiratory Depression with Oliceridine Compared to Morphine: A Retrospective Chart Analysis

Background

Oliceridine, an investigational IV opioid, is a first-in-class G-protein selective agonist at the μ-opioid receptor. The G-protein selectivity results in potent analgesia with less recruitment of β-arrestin, a signaling pathway associated with opioid-related adverse events (ORAEs). In randomized controlled studies in both hard and soft tissue models yielding surgical pain, oliceridine provided effective analgesia with a potential for an improved safety and tolerability profile at equianalgesic doses to morphine. The phase 3, open-label, single-arm, multicenter ATHENA trial demonstrated the safety, tolerability, and effectiveness of oliceridine in moderate to severe acute pain in a broad range of patients undergoing surgery or with painful medical conditions warranting use of an IV opioid. This retrospective, observational chart review study compared respiratory depression events associated with oliceridine administration as found in the ATHENA trial to a control cohort treated with conventional opioids.

Methods

Patients at 18 years of age or older, who underwent colorectal, orthopedic, cardiothoracic, bariatric, or general surgeries between June 2015 and May 2017 in 11 sites participating in the ATHENA trial who received postoperative analgesia either with IV oliceridine or with IV conventional opioids (e.g., morphine alone or in combination with other opioids) (CO cohort); and had a hospital stay >48 hours, were included in this retrospective analysis. Data from the ATHENA trial was used for the oliceridine cohort; and additional baseline characteristics were collected from medical charts. Data from medical charts were collected for all CO cohort patients. The two cohorts were balanced using an inverse probability weighting method. The primary outcome was the incidence of operationally defined opioid-induced respiratory depression (OIRD) in the two cohorts. Secondary outcomes included between-group comparison of the incidence of OIRD events among a subset of high-risk patients.

Results

OIRD was significantly less in the oliceridine cohort compared to the CO cohort (8.0% vs. 30.7%; odds ratio: 0.139) (95% confidence interval [CI] 0.09–0.22; P < 0.0001). Likewise, the incidence of OIRD was lower among high-risk patients in the oliceridine cohort (9.1% vs. 34.7%; odds ratio: 0.136) (95% CI [0.09–0.22]; P < 0.0001) compared to the CO cohort.

Conclusion

In this retrospective chart review study, patients receiving IV oliceridine for moderate to severe acute pain demonstrated a lower incidence of treatment emergent OIRD compared to patients who were treated with IV morphine either alone or with concomitant administration of other opioids.

Evaluating the Incidence of Opioid-Induced Respiratory Depression Associated with Oliceridine and Morphine as Measured by the Frequency and Average Cumulative Duration of Dosing Interruption in Patients Treated for Acute Postoperative Pain

Background and Objective

Opioid-induced respiratory depression (OIRD) is a potentially fatal complication associated with conventional opioids. Currently, there is a paucity of validated endpoints available to measure respiratory safety. Oliceridine, an investigational intravenous (IV) opioid, is a G-protein selective μ-agonist with limited activity on β-arrestin2, a signaling pathway associated with adverse events including OIRD. In controlled phase III trials, oliceridine 0.35 mg and 0.5 mg demand doses demonstrated comparable analgesia to morphine 1 mg with favorable improvements in respiratory safety. In this exploratory analysis, we report dosing interruption (DI) and average cumulative duration of DI (CDDI) for both oliceridine and morphine.

Methods

Patients requiring analgesia after bunionectomy or abdominoplasty were randomized to IV demand doses of placebo, oliceridine (0.1 mg, 0.35 mg, or 0.5 mg), or morphine (1 mg), administered via patient-controlled analgesia (PCA), following a loading dose (oliceridine 1.5 mg, morphine 4 mg, volume-matched placebo) with a 6-min lockout interval. Certified nurse anesthetists monitored each patient and withheld study medication according to the patient’s respiratory status. For each patient, the duration of all DIs was summed and reported as CDDI. A zero-inflated gamma mixture model was used to compute the mean CDDI for each treatment.

Results

Proportion of patients with DI was lower with oliceridine (0.1 mg: 3.2%, 0.35 mg: 13.9%, 0.5 mg: 15.1%) versus morphine (22%). The CDDI was also lower across all demand doses of oliceridine versus morphine.

Conclusion

Using DI as a surrogate for OIRD indicates improved respiratory safety with oliceridine versus morphine that merits further investigation.

Electronic supplementary material

The online version of this article (10.1007/s40261-020-00936-0) contains supplementary material, which is available to authorized users.

Risk of Postoperative Hyperalgesia in Adult Patients with Preoperative Poor Sleep Quality Undergoing Open-heart Valve Surgery

Purpose

Studies have reported that preoperative poor sleep quality could decrease the pain threshold in patients undergoing noncardiac surgery. However, the risk of postoperative hyperalgesia (HA) in cardiac surgery patients with preoperative poor sleep quality remains unclear.

Patients and Methods

We retrospectively collected clinical data from patients undergoing open-heart valve surgery between May 1 and October 31, 2019, in Fuwai Hospital (Beijing). We assessed preoperative sleep quality and postoperative pain severity using the Pittsburgh sleep quality index (PSQI) and numerical pain rating scale (NPRS), respectively. A PSQI of six or greater was considered to indicate poor sleep quality, and a NPRS of four or greater was considered to indicate HA. Multivariable logistic regression analysis was used to study the risk of postoperative HA in patients with preoperative poor sleep quality.

Results

We divided 214 eligible patients into two groups based on postoperative HA; HA group: n=61 (28.5%) and nonHA group: n=153 (71.5%). Compared with nonHA patients, patients with postoperative HA showed a higher percentage of history of smoking, 17 (11.1%) vs 15 (24.6%) and alcohol abuse, 5 (3.3%) vs 6 (9.8%), higher intraoperative dose of sufentanil (median, 1.02 vs 1.12 μg/kg/h), and longer duration of ventilation with tracheal catheter (median, 760 vs 934 min). Preoperative poor sleep quality was associated independently with an increased risk of postoperative HA (adjusted odds ratio [AOR]: 2.66; 95%CI: 1.31–5.39, P=0.007). Stratification by history of smoking revealed a stronger risk of postoperative HA in nonsmoking patients with preoperative poor sleep quality (AOR: 3.40; 95%CI: 1.51–7.66, P=0.003). No risk was found in patients who had history of smoking (AOR: 0.83; 95%CI: 0.14–4.75, P=0.832).

Conclusion

Preoperative poor sleep quality is an independent risk factor for postoperative HA in adult patients undergoing open-heart valve surgery who had no history of smoking.

Postoperative Critical Events Associated With Obstructive Sleep Apnea: Results From the Society of Anesthesia and Sleep Medicine Obstructive Sleep Apnea Registry

BACKGROUND

Obstructive sleep apnea (OSA) patients are at increased risk for pulmonary and cardiovascular complications; perioperative mortality risk is unclear. This report analyzes cases submitted to the OSA Death and Near Miss Registry, focusing on factors associated with poor outcomes after an OSA-related event. We hypothesized that more severe outcomes would be associated with OSA severity, less intense monitoring, and higher cumulative opioid doses.

METHODS

Inclusion criteria were age ≥18 years, OSA diagnosed or suspected, event related to OSA, and event occurrence 1992 or later and <30 days postoperatively. Factors associated with death or brain damage versus other critical events were analyzed by tests of association and odds ratios (OR; 95% confidence intervals [CIs]).

RESULTS

Sixty-six cases met inclusion criteria with known OSA diagnosed in 55 (83%). Patients were middle aged (mean = 53, standard deviation [SD] = 15 years), American Society of Anesthesiologists (ASA) III (59%, n = 38), and obese (mean body mass index [BMI] = 38, SD = 9 kg/m); most had inpatient (80%, n = 51) and elective (90%, n = 56) procedures with general anesthesia (88%, n = 58). Most events occurred on the ward (56%, n = 37), and 14 (21%) occurred at home. Most events (76%, n = 50) occurred within 24 hours of anesthesia end. Ninety-seven percent (n = 64) received opioids within the 24 hours before the event, and two-thirds (41 of 62) also received sedatives. Positive airway pressure devices and/or supplemental oxygen were in use at the time of critical events in 7.5% and 52% of cases, respectively. Sixty-five percent (n = 43) of patients died or had brain damage; 35% (n = 23) experienced other critical events. Continuous central respiratory monitoring was in use for 3 of 43 (7%) of cases where death or brain damage resulted. Death or brain damage was (1) less common when the event was witnessed than unwitnessed (OR = 0.036; 95% CI, 0.007-0.181; P < .001); (2) less common with supplemental oxygen in place (OR = 0.227; 95% CI, 0.070-0.740; P = .011); (3) less common with respiratory monitoring versus no monitoring (OR = 0.109; 95% CI, 0.031-0.384; P < .001); and (4) more common in patients who received both opioids and sedatives than opioids alone (OR = 4.133; 95% CI, 1.348-12.672; P = .011). No evidence for an association was observed between outcomes and OSA severity or cumulative opioid dose.

CONCLUSIONS

Death and brain damage were more likely to occur with unwitnessed events, no supplemental oxygen, lack of respiratory monitoring, and coadministration of opioids and sedatives. It is important that efforts be directed at providing more effective monitoring for OSA patients following surgery, and clinicians consider the potentially dangerous effects of opioids and sedatives-especially when combined-when managing OSA patients postoperatively.

A methodology to explore ventilatory chemosensitivity and opioid-induced respiratory depression risk

Our new and noteworthy methodology allows for exploration of preoperative ventilatory chemosensitivity, measured as the hypercapnic ventilatory response (HCVR), as a risk factor for postoperative opioid-induced respiratory depression (OIRD). This feasible and reliable methodology produced preliminary data that showed highly variable depression of HCVR by remifentanil, predominance of OIRD during light sleep, and potentially negative correlation between OIRD frequency generally and HCVR measurements when measured in the presence of remifentanil. Although the results are preliminary in nature, this novel methodology may guide future studies that can one day lead to effective clinical screening tools.

Postoperative respiratory state assessment using the Integrated Pulmonary Index (IPI) and resultant nurse interventions in the post-anesthesia care unit: a randomized controlled trial

Although postoperative adverse respiratory events, defined by a decrease in respiratory rate (RR) and/or a drop in oxygen saturation (SpO₂), occur frequently, many of such events are missed. The purpose of the current study was to assess whether continuous monitoring of the integrated pulmonary index (IPI), a composite index of SpO₂, RR, end-tidal PCO₂ and heart rate, alters our ability to identify and prevent adverse respiratory events in postoperative patients. Eighty postoperative patients were subjected to continuous respiratory monitoring during the first postoperative night using RR and pulse oximetry and the IPI monitor. Patients were randomized to receive intervention based on standard care (observational) or based on the IPI monitor (interventional). Nurses were asked to respond to adverse respiratory events with an intervention to improve the patient’s respiratory condition. There was no difference in the number of patients that experienced at least one adverse respiratory event: 21 and 16 in observational and interventional group, respectively (p = 0.218). Compared to the observational group, the use of the IPI monitor led to an increase in the number of interventions performed by nurses to improve the respiratory status of the patient (average 13 versus 39 interventions, p < 0.001). This difference was associated with a significant reduction of the median number of events per patient (2.5 versus 6, p < 0.05) and a shorter median duration of events (62 s versus 75 s, p < 0.001). The use of the IPI monitor in postoperative patients did not result in a reduction of the number of patients experiencing adverse respiratory events, compared to standard clinical care. However, it did lead to an increased number of nurse interventions and a decreased number and duration of respiratory events in patients that experienced postoperative adverse respiratory events.

Preoperative Optimization for Perioperative Analgesia

The perioperative analgesic plan begins with preoperative planning. The surgeon should be versed in practical approaches for managing analgesia in patients with chronic pain. The first step includes evaluating the patient and conducting a focused pain history. Confirming, documenting, and understanding current outpatient prescriptions is critical. Patients should be screened for medical conditions that preclude the use of certain analgesics, or place them at higher risk of respiratory depression. Providers should coordinate with the patient's outpatient prescribers and pain specialists to ensure a safe and effective analgesic plan. Multimodal analgesia should be implemented to optimize analgesia and decrease opioid requirements.

Novel Oral Nanoparticle Formulation of Sustained Release Naloxone with Mild Withdrawal Symptoms in Mice

Chronic use of opioids can lead to tolerance, dependence, abuse, and addiction. This in turn can result in dose escalation and opioid overdose. Opioid overdose can be fatal due to severe opioid-induced respiratory depression (OIRD). Naloxone, a nonspecific antagonist of the mu-opioid receptors, is used for the reversal of OIRD. However, one of the major challenges of using naloxone is its short elimination half-life, which is significantly shorter compared to many opioid analgesics. Thus, renarcotization and rapid return to full respiratory depression might occur, specifically in individuals who have taken large doses or long-acting opioid formulations. Additionally, because of the very low oral bioavailability of naloxone, an oral formulation is not currently available. This study examines in mice a novel oral formulation of naloxone based on polymer nanoparticles (NP-naloxone). A single dose of 1 or 5 mg/kg NP-naloxone was highly effective at inhibiting the activating effects of repeated administration of 10 mg/kg morphine for at least up to 24 h. Onset of action was approximately 5 min. Reversal of morphine-induced locomotion was already detected within 1 min and a full effect of returning to baseline activity levels was observed within 5 min. Importantly, at 1 mg/kg, NP-naloxone precipitated very minimal withdrawal behaviors. At the 5 mg/kg dose, NP-naloxone precipitated approximately 40% of the jumping withdrawal behaviors of injectable naloxone. Thus, this study demonstrates that orally administered naloxone based on polymer nanoparticles has high potential to be developed to circumvent OIRD and withdrawal symptoms.

Opioid-free anesthesia-caution for a one-size-fits-all approach

Post-operative pain management should ideally be optimized to ensure patient’s mobilization and ability to partake in effective pulmonary exercises for patient’s early recovery. Opioids have traditionally been the main mode for analgesia strategy in the perioperative period. However, the recent focus on opioid crisis in the USA has generated a robust discussion on rational use of opioids in the perioperative period and also raised the concept of “opioid-free anesthesia” in certain circles. Opioid-related adverse drug events (ORADE) and questionable role of opioids in cancer progression have further deterred some anesthesiologists from the routine perioperative use of opioids including their use for breakthrough pain. However, judicious use of opioid in conjunction with the use of non-opioid analgesics and regional anesthetic techniques may allow for optimal analgesia while reducing the risks associated with the use of opioids. Importantly, the opioid epidemic and opioid-related deaths seem more related to the prescription practices of physicians and post-discharge misuse of opioids. Focus on patient and clinician education, identification of high-risk patients, and instituting effective drug disposal and take-back policies may prove useful in reducing opioid misuse.

Prevalence of sleep-disordered breathing in opioid users with chronic pain: a systematic review and meta-analysis

STUDY OBJECTIVES

Opioids have been reported to increase the risk for sleep-disordered breathing (SDB) in patients with noncancer chronic pain on opioid therapy. This study aims to determine the pooled prevalence of SDB in opioid users with chronic pain and compare it with patients with pain:no opioids and no pain:no opioids.

METHODS

A literature search of PubMed, Medline, Embase, and Cochrane Central Register of Controlled Trials was conducted. We included all observational studies that reported the prevalence of SDB in patients with chronic pain on long-term opioid therapy (≥3 months). The primary outcome was the pooled prevalence of SDB in opioid users with chronic pain (pain:opioids group) and a comparison with pain:no opioids and no pain:no opioids groups. The meta-analysis was performed using a random-effects model.

RESULTS

After screening 1,404 studies, 9 studies with 3,791 patients were included in the meta-analysis (pain:opioids group, n = 3181 [84%]; pain:no opioids group, n = 359 [9.4%]; no pain:no opioids group, n = 251 [6.6%]). The pooled prevalence of SDB in the pain:opioids, pain:no opioids, and no pain:no opioids groups were 91%, 83%, and 72% in sleep clinics and 63%, 10%, and 75% in pain clinics, respectively. Furthermore, in the pain: opioids group, central sleep apnea prevalence in sleep and pain clinics was 33% and 20%, respectively.

CONCLUSIONS

The pooled prevalence of SDB in patients with chronic pain on opioid therapy is not significantly different compared with pain:no opioids and no pain:no opioids groups and varies considerably depending on the site of patient recruitment (ie, sleep vs pain clinics). The prevalence of central sleep apnea is high in sleep and pain clinics in the pain:opioids group. Clinical Trial Registration: Registry: PROSPERO: International prospective register of systematic reviews; Name: Prevalence of sleep disordered breathing, hypoxemia and hypercapnia in patients on oral opioid therapy for chronic pain management; URL: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42018103298; Identifier: CRD42018103298.

Delphi Study: ASPAN Adult Patient Pain and Comfort Practices

PURPOSE

The American Society of PeriAnesthesia Nurses (ASPAN) is responsible for establishing evidence-based standards to guide perianesthesia nursing practice. The ASPAN model for evidence-based practice acknowledges the potential for the Delphi technique to identify priorities for perianesthesia research. The purpose of this Delphi study was to generate a consensus on pain and comfort among a panel of experts.

DESIGN

ASPAN convened a panel of experts to provide recommendations based on seven categories, this led to the development of a questionnaire to build consensus.

METHODS

Survey conducted among panel of experts to obtain consensus. Two survey rounds were completed.

FINDINGS

A consensus was obtained reaching a 70% benchmark for an acceptance.

CONCLUSIONS

The results found a consensus on topics required for education and competency among perianesthesia nurses including transfer and discharge criteria related to pain and comfort, resources for perianesthesia nurses, policy guidelines, and the management of the special needs of perianesthesia patients.

Characterization of respiratory compromise and the potential clinical utility of capnography in the post-anesthesia care unit: a blinded observational trial

The utility of capnography to detect early respiratory compromise in surgical patients after anesthesia is unclear due to limited prospective data. The purpose of this trial was to determine the frequency and duration of capnography-detected respiratory adverse events in the post-anesthesia care unit (PACU). In this prospective observational trial, 250 consenting patients undergoing elective surgery with general anesthesia were monitored by standard monitoring together with blinded capnography and pulse oximetry monitoring. The capnography notification settings were adjusted to match nursing (Level II) and physician (Level I) alarm thresholds. 163 (95%) patients had a Level II notification and 135 (78%) had a Level I notification during standard monitoring. The most common events detected by the capnography monitor included hypocapnia, apnea, tachypnea, bradypnea and hypoxemia, with silent notification duration for these events ranging from 17 ± 13 to 189 ± 127 s. During standard monitoring, 15 respiratory adverse events were reported, with 8 events occurring when valid blinded/silenced capnography and pulse oximetry data was collected simultaneously. Capnography and the Integrated Pulmonary Index™ algorithm (IPI) detected respiratory adverse events earlier than standard monitoring in 75% and 88% of cases, respectively, with an average early warning time of 8 ± 11 min. Three patients’ blinded capnography was unblinded to facilitate clinical care. Respiratory adverse events are frequent in the PACU, and the addition of capnography and IPI to current standard monitoring provides potentially clinically relevant information on respiratory status, including early warning of some respiratory adverse events.

Trial registration ClinialTrials.gov Identifier NCT02707003 (https://clinicaltrials.gov/ct2/show/NCT02707003).