Obstructive sleep apnea, pain, and opioids: is the riddle solved?

Surgical transversus abdominis plane block with liposomal bupivacaine at cesarean: a pilot randomized trial

BACKGROUND

Postcesarean pain control is challenging. In addition to intrathecal morphine, recent studies have shown that liposomal bupivacaine administered via conventional transversus abdominis plane block reduces postcesarean opioid use. However, whether the administration of liposomal bupivacaine via a surgical approach also reduces opioid use is unknown.

OBJECTIVE

This study aimed to investigate whether the administration of liposomal bupivacaine via surgical transversus abdominis plane block (TAP block) reduces the cumulative dose of opioids administered in the first 48 hours after cesarean delivery among participants who also receive intrathecal morphine.

STUDY DESIGN

This was a pilot single-blind randomized controlled trial of 60 parturients undergoing cesarean delivery at a community tertiary referral hospital staffed by academic physicians. Immediately before fascial closure during cesarean delivery, a total of 80 mL of dilute bupivacaine plus liposomal bupivacaine or dilute bupivacaine alone was administered via surgical transversus abdominis plane block (40 mL on each side). The primary outcome was a median cumulative opioid dose received within the first 48 hours after cesarean delivery measured in morphine milligram equivalents. In addition, opioid use at other time points, pain scores, and participant satisfaction were assessed. A sample size of 60 was determined to be adequate to inform a potential future adequately powered randomized trial. The primary outcome of morphine milligram equivalents and pain scores were compared using a Wilcoxon rank-sum test.

RESULTS

Between October 11, 2021, and August 29, 2022, 60 participants were randomized and analyzed: 31 were allocated to liposomal bupivacaine plus regular bupivacaine (intervention group), and 29 were allocated to regular bupivacaine alone (control group). Participants allocated to the intervention group used a median cumulative dose of 2 morphine milligram equivalents of opioids (interquartile range, 0-24) in the first 48 hours compared with 8 morphine milligram equivalents (interquartile range, 0-40) among participants allocated to the control group (P=.236). The percentage of participants who used ≤15 morphine milligram equivalents of opioids was 61% in the intervention arm and 41% in the control arm (P=.123), and the percentage who used zero opioids was 45% in the intervention arm and 34% in the control arm (P=.399). The total number of opioid pills prescribed at discharge was fewer in the intervention arm than in the control arm (P=.029). Patient satisfaction with the intervention group and control group was similar.

CONCLUSION

Our pilot study suggests that liposomal bupivacaine administered via surgical transversus abdominis plane block is worth critical evaluation as an adjunctive analgesic modality in an adequately powered randomized trial.

Opioid sensitivity in treated and untreated obstructive sleep apnoea: a prospective cohort study

BACKGROUND

Opioid administration to patients with obstructive sleep apnoea (OSA) is controversial because they are believed to be more sensitive to opioids. However, objective data on opioid effects in OSA are lacking. We tested the hypothesis that subjects with untreated OSA have increased sensitivity to opioids compared with subjects without OSA, or with OSA treated with continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BIPAP).

METHODS

This was a single-centre, prospective cohort study in subjects without OSA (n=20), with untreated OSA (n=33), or with treated OSA (n=21). OSA diagnosis was verified using type III (in-home) polysomnography. Subjects received a stepped-dose remifentanil infusion (target effect-site concentrations of 0.5, 1, 2, 3, 4 ng ml-1). Primary outcome was miosis (pupil area fractional change), the most sensitive opioid effect. Secondary outcomes were ventilatory rate, end-expired CO2, sedation, and thermal analgesia.

RESULTS

There were no differences in miosis between untreated OSA subjects (mean=0.51, 95% confidence interval [CI] 0.41-0.61) and subjects without OSA (mean=0.49, 95% CI 0.36-0.62) (mean difference=0.02, 95% CI -0.18 to 0.22); between treated OSA subjects (mean=0.56, 95% CI 0.43-0.68) and subjects without OSA (difference=0.07, 95% CI -0.16 to 0.29); or between untreated OSA and treated OSA (difference=-0.05, 95% CI -0.25 to 0.16). There were no significant differences between subjects without OSA, untreated OSA, and treated OSA in ventilatory rate, end-expired CO2, sedation, or thermal analgesia responses to remifentanil. There was no relationship between OSA severity and magnitude of opioid effects.

CONCLUSIONS

Neither obstructive sleep apnoea nor obstructive sleep apnoea treatment affected sensitivity to the miotic, sedative, analgesic, or respiratory depressant effects of the opioid remifentanil in awake adults. These results challenge conventional notions of opioid effects in obstructive sleep apnoea.

CLINICAL TRIAL REGISTRATION

NCT02898792 (clinicaltrials.gov).

The efficacy of intranasal leptin for opioid-induced respiratory depression depends on sex and obesity state

Introduction: Opioid-induced respiratory depression (OIRD) is the primary cause of death associated with opioids and individuals with obesity are particularly susceptible due to comorbid obstructive sleep apnea (OSA). Repeated exposure to opioids, as in the case of pain management, results in diminished therapeutic effect and/or the need for higher doses to maintain the same effect. With limited means to address the negative impact of repeated exposure it is critical to develop drugs that prevent deaths induced by opioids without reducing beneficial analgesia. Methods: We hypothesized that OIRD as a result of chronic opioid use can be attenuated by administration of IN leptin while also maintaining analgesia in both lean mice and mice with diet-induced obesity (DIO) of both sexes. To test this hypothesis, an opioid tolerance protocol was developed and a model of OIRD in mice chronically receiving morphine and tolerant to morphine analgesia was established. Subsequently, breathing was recorded by barometric plethysmography in four experimental groups: obese male, obese female, lean male, and lean female following acute administration of IN leptin. Respiratory data were complemented with measures of arterial blood gas. Operant behavioral assays were used to determine the impact of IN leptin on the analgesic efficacy of morphine. Results: Acute administration of IN leptin significantly attenuated OIRD in DIO male mice decreasing the apnea index by 58.9% and apnea time by 60.1%. In lean mice leptin was ineffective. Blood gas measures confirmed the effectiveness of IN leptin for preventing respiratory acidosis in DIO male mice. However, IN leptin was not effective in lean mice of both sexes and appeared to exacerbate acid-base disturbances in DIO female mice. Additionally, morphine caused a complete loss of temperature aversion which was not reduced by intranasal leptin indicating IN leptin does not decrease morphine analgesia. Discussion: IN leptin effectively treated OIRD in morphine-tolerant DIO male mice without impacting analgesia. In contrast, IN leptin had no effect in lean mice of either sex or DIO female mice. The arterial blood gas data were consistent with ventilatory findings showing that IN leptin reversed morphine-induced respiratory acidosis only in DIO male mice but not in other mouse groups. Finally, a hypercapnic sensitivity study revealed that IN leptin rescued minute ventilation under hypercapnic conditions only in DIO male mice, which suggests that differential responses to IN leptin are attributable to different leptin sensitivities depending on sex and the obesity status.

Artificial intelligent patient-controlled intravenous analgesia improves the outcomes of older patients with laparoscopic radical resection for colorectal cancer

METHODS

Patients undergoing elective laparoscopic radical resection of colorectal cancer from July 2019 to May 2021 were selected. The patients were assigned to Ai-PCIA group and control group. Ai-PCIA group received postoperative analgesia management and effect evaluation through intelligent wireless analgesia system + postoperative follow-up twice a day, while control group received analgesia management and effect evaluation through ward physician feedback + postoperative follow-up twice a day. The pain numerical score (NRS), Richards-Campbell Sleep Scale (RCSQ), and adverse outcomes were collected and compared.

RESULTS

A total of 60 patients (20 females and 40 males with average (78.26 ± 6.42) years old) were included. The NRS scores at rest and during activity of the Ai-PCA group at 8, 12, and 24 h after the operation were significantly lower than that of the control group (all P < 0.05). The RCSQ score of Ai-PCA group was significantly higher than that of control group on the 1st and 2nd days after operation (all P < 0.05). There were no significant differences in the incidence of dizziness and nausea, vomiting, and myocardial ischemia (all P > 0.05).

CONCLUSIONS

Ai-PCIA can improve the analgesic effect and sleep quality of older patients after laparoscopic radical resection, which may be promoted in clinical analgesia practice.

Mechanisms underlying the health benefits of intermittent hypoxia conditioning

Intermittent hypoxia (IH) is commonly associated with pathological conditions, particularly obstructive sleep apnoea. However, IH is also increasingly used to enhance health and performance and is emerging as a potent non-pharmacological intervention against numerous diseases. Whether IH is detrimental or beneficial for health is largely determined by the intensity, duration, number and frequency of the hypoxic exposures and by the specific responses they engender. Adaptive responses to hypoxia protect from future hypoxic or ischaemic insults, improve cellular resilience and functions, and boost mental and physical performance. The cellular and systemic mechanisms producing these benefits are highly complex, and the failure of different components can shift long-term adaptation to maladaptation and the development of pathologies. Rather than discussing in detail the well-characterized individual responses and adaptations to IH, we here aim to summarize and integrate hypoxia-activated mechanisms into a holistic picture of the body's adaptive responses to hypoxia and specifically IH, and demonstrate how these mechanisms might be mobilized for their health benefits while minimizing the risks of hypoxia exposure.

Prevalence and characteristics of pain in moderate-to-severe obstructive sleep apnea patients and effect of CPAP treatment

Pain problems are common in patients with obstructive sleep apnea (OSA), but few studies have thoroughly evaluated pain in these patients. The objective of this study was to examine the prevalence and characteristics of pain in moderate-to-severe OSA patients and the effect of continuous positive airway pressure (CPAP) treatment. Moderate-to-severe OSA patients and healthy controls (HC) completed the Short Form McGill Pain Questionnaire (SF-MPQ) and a portion of the Brief Pain Inventory (BPI) Short Form to assess pain characteristics. The Epworth Sleepiness Scale (ESS), the Short Form-36 (SF-36), and the Hospital Anxiety and Depression Scale (HADS) were used to measure daytime sleepiness, health-related quality of life (HRQoL), and psychological status, respectively. The OSA patients with pain were divided into a CPAP-treated group and a CPAP-untreated group based on their adherence to CPAP. The subjects' pain intensity was reassessed after 3 months. The prevalence of pain was 57.5% in OSA versus 27.1% in HC (p < 0.001). Head (39.0%) accounted for the highest proportion of overall pain locations in subjects with OSA, with 28.8% of OSA patients experiencing headaches. Pain in OSA was associated with impaired HRQoL and psychological problems. Patients with very severe OSA had an increased risk for pain problems (OR: 7.000, p = 0.041). Associated factors for pain intensity in OSA included age, ESS ≥ 9.0, and lowest pulse oximetry (LSpO2) < 80.0%. Pain intensity in OSA decreased significantly after CPAP treatment (p < 0.001). Pain was prevalent among patients with moderate-to-severe OSA and was associated with depression, anxiety, and a lower HRQoL. Patients with very severe OSA had an increased risk for pain problems. The intensity of pain in OSA can be predicted by age, ESS ≥ 9.0, and LSpO2 < 80.0%, and it can be alleviated through CPAP treatment.

Pro-Con Debate: Role of Methadone in Enhanced Recovery After Surgery Protocols-Superior Analgesic or Harmful Drug?

Enhanced recovery after surgery (ERAS) protocols are standardized and designed to provide superior analgesia, reduce opioid consumption, improve patient recovery, and reduce hospital length of stay. Yet, moderate-to-severe postsurgical pain continues to afflict over 40% of patients and remains a major priority for anesthesia research. Methadone administration in the perioperative setting may reduce postoperative pain scores and have opioid-sparing effects, which may be beneficial for enhanced recovery. Methadone possesses a multimodal profile consisting of µ-opioid agonism, N-methyl-d-aspartate (NMDA) receptor antagonism, and reuptake inhibition of serotonin and norepinephrine. Furthermore, it may attenuate the development of chronic postsurgical pain. However, caution is advised with perioperative use of methadone in specific high-risk patient populations and surgical settings. Methadone's wide pharmacokinetic variability, opioid-related adverse effects, and potential negative impact on cost-effectiveness may also limit its use in the perioperative setting. In this PRO-CON commentary article, the authors debate whether methadone should be incorporated in ERAS protocols to provide superior analgesia with no increased risks.

Opioid-Based vs Opioid-Free Anesthesia in Breast Cancer Surgery

Introduction

Breast cancer is the most widely recognized malignant growth in ladies in India and accounts for 14% of all tumors in women. Modified radical mastectomy (MRM) is a surgery done for breast cancer. It leads to about 30% chances of postoperative nausea and vomiting (PONV) and 40% pain in the immediate postoperative period.

Objectives

Changes in blood pressure after intubation, waiting time for postoperative pain medication, and possibility of adverse effects.

Methodology

After the approval of ethical committee, the study was conducted in the procedure and possible complications associated with the procedure were explained to patients. Written informed consent was obtained from each patient.

Result and Conclusion

We conclude that opioid-free anesthesia is "more effective in reducing the incidence of postoperative nausea and vomiting, produces stable hemodynamics, and reduces incidence of side effects when compared with opioid-based general anesthesia in patients undergoing breast cancer surgeries."

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.

Systemic Factors in Temporomandibular Disorder Pain

The science of temporomandibular disorder (TMD) pain and its management has gone through significant changes during the last several decades. The authors strongly feel that the effect of systemic factors influencing TMD pain has been largely overlooked and poorly accounted for, even in established pain-management programs and protocols. The hope is that this article will act as a wake-up call for the pain management community to consider the importance of adequate knowledge of the systemic factors that affect the experience of TMD pain by the patient.

Sleep study measures on post-operative night one following expansion pharyngoplasty for obstructive sleep apnea

PURPOSE

To examine the changes in measures of sleep apnea severity and hypoxemia on the first post-operative night (PON1) following expansion pharyngoplasty as a means to assess the safety of same day discharge after surgery.

MATERIALS AND METHODS

Prospective cohort study of subjects with moderate-severe obstructive sleep apnea who underwent expansion pharyngoplasty at a single academic sleep surgical practice. A WatchPAT study was performed on the night immediately following surgery (PON1) and comparisons were made to baseline sleep testing.

RESULTS

Twenty subjects who had a mean age of 45.7 ± 10.8 years old and a mean body-mass index (BMI) of 31.4 ± 3.2 kg/m² were enrolled. Patients had baseline severe OSA with mean apnea hypopnea index (AHI) 39.4 ± 19.5/h, O2 nadir 80.8 ± 6.1 % and time with oxygen saturation below 88 % (T88) 12.3 ± 13.2 min. Measures of sleep apnea and nocturnal hypoxemia were not significantly different on PON1. AHI was increased by >20 % in 11 (55.0 %) patients. One patient demonstrated a >10 % worsening in O2 nadir, and 8 patients (45.0 %) demonstrated a >20 % worsening in T88. BMI over 32 was associated with elevated odds of worsening in T88, and anesthesia involving ketamine was associated with lower odds of a 20 % worsening in AHI or T88.

CONCLUSIONS

On PON1 following expansion pharyngoplasty, AHI and nocturnal hypoxemia are stable overall but variable on an individual basis. The decision for admission should therefore be made on a case-by-case basis. Further research is need to elucidate definitive predictors of worsening measures on PON1.

Nocturnal respiratory abnormalities among ward-level postoperative patients as detected by the Capnostream 20p monitor: A blinded observational study

PURPOSE

This prospective observational study aimed to establish the frequency of postoperative nocturnal respiratory abnormalities among patients undergoing major surgery who received ward-level care. These abnormalities may have implications for postoperative pulmonary complications (PPCs).

METHODS

Eligible patients underwent blinded noninvasive continuous capnography with pulse oximetry using the Capnostream™ 20p monitor over the first postoperative night. All patients received oxygen supplementation and patient-controlled opioid analgesia. The primary outcome was the number of prolonged apnea events (PAEs), defined as end-tidal carbon dioxide (EtCO2) ≤5 mmHg for 30-120 seconds or EtCO2 ≤5 mmHg for >120 seconds with oxygen saturation (SpO2) <85%. Secondary outcomes were the proportion of recorded time that physiological indices were aberrant, including the apnea index (AI), oxygen desaturation index (ODI), integrated pulmonary index (IPI), and SpO2. Exploratory analysis was conducted to assess the associations between PAEs, PPCs, and pre-defined factors.

RESULTS

Among 125 patients who had sufficient data for analysis, a total of 1800 PAEs occurred in 67 (53.4%) patients. The highest quartile accounted for 89.1% of all events. Amongst patients who experienced any PAEs, the median (IQR) number of PAE/patient was four (2-12). As proportions of recorded time (median (IQR)), AI, ODI, and IPI were aberrant for 12.4% (0-43.2%), 19.1% (2.0-57.1%), and 11.5% (3.1-33.3%) respectively. Only age, ARISCAT, and opioid consumption/kg were associated with PPCs.

CONCLUSIONS

PAE and aberrant indices were frequently detected on the first postoperative night. However, they did not correlate with PPCs. Future research should investigate the significance of detected aberrations.

Associations between early sleep-disordered breathing following moderate-to-severe traumatic brain injury and long-term chronic pain status: a Traumatic Brain Injury Model Systems study

STUDY OBJECTIVES

To explore the relationship between polysomnography-derived respiratory indices and chronic pain status among individuals following traumatic brain injury (TBI).

METHODS

Participants (n = 66) with moderate to severe TBI underwent polysomnography during inpatient acute rehabilitation and their chronic pain status was assessed at 1- to 2-year follow-up as part of the TBI Model Systems Pain Collaborative Study. Pairwise comparisons across pain cohorts (ie, chronic pain, no history of pain) were made to explore differences on polysomnography indices.

RESULTS

Among our total sample, approximately three-quarters (74.2%) received sleep apnea diagnoses utilizing American Academy of Sleep Medicine criteria, with 61.9% of those endorsing a history of chronic pain. Of those endorsing chronic pain, the average pain score was 4.8 (standard deviation = 2.1), with a mean interference score of 5.3 (2.7). Pairwise comparisons revealed that those endorsing a chronic pain experience at follow-up experienced categorically worse indicators of sleep-related breathing disorders during acute rehabilitation relative to those who did not endorse chronic pain. Important differences were observed with elevations on central (chronic pain: 2.6; no pain: 0.8 per hour) and obstructive apnea (chronic pain: 15.7; no pain: 11.1 per hour) events, as well as oxygen desaturation indices (chronic pain: 19.6; no pain: 7.9 per hour).

CONCLUSIONS

Sleep-disordered breathing appears worse among those who endorse chronic pain following moderate-to-severe TBI, but additional research is needed to understand its relation to postinjury pain. Prospective investigation is necessary to determine how clinical decisions (eg, opioid therapy) and intervention (eg, positive airway pressure) may mutually influence outcomes.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Comparison of Sleep Apnea Assessment Strategies to Maximize TBI Rehabilitation Participation and Outcome (C-SAS); URL: https://clinicaltrials.gov/ct2/show/NCT03033901; Identifier: NCT03033901.

CITATION

Martin AM, Pinto SM, Tang X, et al. Associations between early sleep-disordered breathing following moderate-to-severe traumatic brain injury and long-term chronic pain status: a Traumatic Brain Injury Model Systems study. J Clin Sleep Med. 2023;19(1):135-143.

Sleep Disturbances and Disorders in Patients with Knee Osteoarthritis and Total Knee Arthroplasty

➤

There is increasing evidence that patient-reported outcomes following total knee arthroplasty (TKA) are associated with psychosocial factors and pain catastrophizing. Sleep disturbance, pain, and mental health have a complex interaction, which, if unrecognized, can be associated with impaired patient-reported outcomes and dissatisfaction following TKA.

➤

The gold standard of objective sleep assessment is polysomnography, which is not feasible to use routinely for TKA patients. Wearable devices are a validated and less costly alternative.

➤

Subjective sleep measures, such as the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, or Patient-Reported Outcomes Measurement Information System (PROMIS) computerized adaptive test sleep domains, are simple to administer and provide additional insight into sleep disturbance. Although objective and subjective measures do not correlate precisely, they can be informative together.

➤

Sleep disturbances in the elderly population are common and multifactorial in etiology, stemming from the interplay of sleep disorders, medication side effects, and pain. Commonly prescribed medications following TKA as well as postoperative pain can exacerbate underlying sleep disturbances.

➤

Obstructive sleep apnea (OSA) is prevalent in patients seeking TKA. In the setting of OSA, postoperative opioids can cause respiratory depression, resulting in consequences as severe as death. A standardized multimodal pain protocol including anti-inflammatories and gamma-aminobutyric acid (GABA) analogues may allow for decreased reliance on opioids for pain control.

➤

Surgeons should reassure patients that postoperative sleep disturbance is common and transient, collaborate with the patient's primary care doctor to address sleep disturbance, and avoid prescription of pharmaceutical sleep aids.

Associations between obstructive sleep apnea and painful temporomandibular disorder: a systematic review

The relationship between obstructive sleep apnea (OSA) and diverse types of pain conditions have been proposed. However, no consensus on the relationship between OSA and painful temporomandibular disorders (TMDs) has been established. Therefore, this systematic review has been conducted to review the existing literatures and provide comprehensive synthesis of such literatures about OSA and painful TMDs using the evidence-based methodology. A literature search was conducted using two electronic databases, Scopus, and PubMed. Risk of bias was assessed using the risk-ofbias assessment tool for non-randomized study version 2.0. A total of 158 articles were screened from the initial search and eventually, 5 articles were included in this systematic review. One study adopted both the longitudinal prospective cohort and case-control designs and other 4 articles adopted the cross-sectional design. Two studies employed polysomnography (PSG) for the diagnosis of OSA and mentioned the results from the PSG. All crosssectional studies demonstrated higher OSA prevalence among patients with TMD, and one cohort study suggested OSA as a risk factor for TMD. OSA appears to have potential influences on the development of TMD; however, the role of TMD in the development of OSA remains to be unknown owing to the lack of high-quality evidences.

Opioid dose and postoperative respiratory adverse events after adenotonsillectomy in medically complex children

STUDY OBJECTIVES

Obstructive sleep-disordered breathing is commonly treated with adenotonsillectomy. Our study objective was to describe perioperative opioid dosing in children with a range of medical complexity evaluated for obstructive sleep-disordered breathing undergoing adenotonsillectomy and to investigate its association with postoperative respiratory adverse events (PRAEs).

METHODS

A retrospective chart review of children who underwent adenotonsillectomy and had preoperative polysomnography performed was conducted. PRAEs included requiring oxygen, jaw thrust, positive airway pressure, or mechanical ventilation. Multivariable logistic regression was performed to examine for associations between covariates and PRAEs.

RESULTS

The cohort included 374 children with obstructive sleep-disordered breathing, median (interquartile range) age 6.1 (3.9, 9.3) years; 344 (92%) had obstructive sleep apnea (apnea-hypopnea index > 1 events/h) while 30 (8%) had a normal polysomnogram (apnea-hypopnea index < 1 events/h). The median (interquartile range) postoperative morphine-equivalent dose administered was 0.17 (0.09, 0.25) mg/kg. Sixty-six (17.6%) experienced at least 1 PRAE. Multivariable modeling identified the following predictors of PRAE: younger age at surgery (odds ratio 0.90, 95% confidence interval 0.83, 0.98), presence of cardiac comorbidity (odds ratio 2.07, 95% confidence interval 1.09, 3.89), and presence of airway anomaly (odds ratio 3.48, 95% confidence interval 1.30, 8.94). Higher total apnea-hypopnea index and morphine-equivalent dose were associated with PRAE risk, and an interaction between these variables was detected (P = .01).

CONCLUSIONS

This study identified opioid dose in morphine equivalents to be a strong predictor of PRAE. Additionally, severity of obstructive sleep apnea and postoperative morphine-equivalent dose contributed together and independently to the occurrence of PRAEs. Attention to opioid dosing, particularly among medically complex children with obstructive sleep-disordered breathing, is required to mitigate risk of PRAEs.

CITATION

Tsampalieros A, Murto K, Barrowman N, et al. Opioid dose and postoperative respiratory adverse events after adenotonsillectomy in medically complex children. J Clin Sleep Med. 2022;18(10):2405-2413.

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.

The evidence base for US joint commission hospital accreditation standards: cross sectional study

OBJECTIVE

To evaluate the evidence upon which standards for hospital accreditation by The Joint Commission on Accreditation of Healthcare Organizations (the Joint Commission) are based.

DESIGN

Cross sectional study.

SETTING

United States.

PARTICIPANTS

Four Joint Commission R3 (requirement, rationale, and reference) reports released by July 2018 and intended to become effective between 1 July 2018 and 1 July 2019.

INTERVENTIONS

From each R3 report the associated standard and its specific elements of performance (or actionable standards) were extracted. If an actionable standard enumerated multiple requirements, these were separated into distinct components. Two investigators reviewed full text references, and each actionable standard was classified as either completely supported, partly supported, or not supported; Oxford evidence quality ratings were assigned; and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) was used to assess the strength of recommendations.

MAIN OUTCOME MEASURE

Strengths of recommendation for actionable standards.

RESULTS

20 actionable standards with 76 distinct components were accompanied by 48 references. Of the 20 actionable standards, six (30%) were completely supported by cited references, six were partly supported (30%), and eight (40%) were not supported. Of the six directly supported actionable standards, one (17%) cited at least one reference of level 1 or 2 evidence, none cited at least one reference of level 3 evidence, and five (83%) cited references of level 4 or 5 evidence. Of the completely supported actionable standards, strength of recommendation in five was deemed GRADE D and in one was GRADE B.

CONCLUSIONS

In general, recent actionable standards issued by The Joint Commission are seldom supported by high quality data referenced within the issuing documents. The Joint Commission might consider being more transparent about the quality of evidence and underlying rationale supporting each of its recommendations, including clarifying when and why in certain instances it determines that lower level evidence is sufficient.

The Effect of Pre-Emptive Analgesia on the Postoperative Pain in Pediatric Otolaryngology: A Randomized, Controlled Trial

The aim of this randomized, controlled trial was to determine whether children undergoing otolaryngological procedures (adenoidectomy, adenotonsillotomy, or tonsillectomy) benefit from pre-emptive analgesia in the postoperative period. Methods: Fifty-five children were assessed for eligibility for the research. Four children refused to participate during the first stage of the study, leaving fifty-one (n = 51) to be randomly assigned either to receive pre-emptive analgesic acetaminophen (15 mg/kg; n = 26) or a placebo (n = 25) in addition to midazolam (0.5 mg/kg) as premedication. All children were anesthetized with sevoflurane, propofol (2−4 mg/kg), and fentanyl (2 mcg/kg). Postoperative pain was assessed using the Visual Analogue Scale (VAS), the Wong−Baker Faces Pain Rating Scale, and the Face, Legs, Activity, Cry, and Consolability (FLACC) scale. The postoperative pain was measured 1, 2, 4, and 6 h after the surgery. Results: The clinical trial reported a statistically significant correlation between administering pre-emptive analgesia (acetaminophen) and reducing pain in children after otolaryngological procedures compared to placebo. The ratio of boys to girls and age were similar among the groups (p > 0.05), so the groups of children were not divided by gender or age. Conclusions: Standard pre-emptive analgesia reduced the severity of pain in the postoperative period after otolaryngological procedures in children. Acetaminophen given before surgery reduces postoperative pain in children undergoing otolaryngological procedures.

Perioperative Pain Management in Bariatric Anesthesia

Weight loss (bariatric) surgery is the most commonly performed elective surgical procedure in patients with morbid obesity. In this review, we provide an evidence-based update on perioperative pain management in bariatric anesthesia. We mention some newer preoperative aspects—medical optimization, physical preparation, patient education, and psychosocial factors—that can all improve pain management. In the intraoperative period, with bariatric surgery being almost universally performed laparoscopically, we emphasize the use of non-opioid adjuvant infusions (ketamine, lidocaine, and dexmedetomidine) and suggest some novel regional anesthesia techniques to reduce pain, opioid requirements, and side effects. We discuss some postoperative strategies that additionally focus on patient safety and identify patients at risk of persistent pain and opioid use after bariatric surgery. This review suggests that the use of a structured, step-wise, severity-based, opioid-sparing multimodal analgesic protocol within an enhanced recovery after surgery (ERAS) framework can improve postoperative pain management. Overall, by incorporating all these aspects throughout the perioperative journey ensures improved patient safety and outcomes from pain management in bariatric anesthesia.

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.

The influence of acute morphine use on obstructive sleep apnea: A systematic review and meta-analysis

The present study was conducted to systematically evaluate the acute effect of morphine on obstructive sleep apnea (OSA). The PubMed, Embase, Cochrane Library, Clinicaltrials.gov, China National Knowledge Infrastructure (CNKI), and Wan-Fang databases were searched for randomised controlled trials studying the influence of morphine on OSA published up to May 24, 2021. The Cochrane risk of bias tool was used to assess study quality and meta-analysis was performed on the included clinical trial results to quantify the impact of morphine on various sleep and respiratory parameters. Three studies (n = 132 patients) were ultimately examined. There were no significant differences between patients with OSA taking morphine and placebo/non-opioids with respect to the sleep Apnea-Hypopnea Index (mean difference [MD] 1.78, 95% confidence interval [CI] -2.41, 5.98; p > 0.05); Oxygen Desaturation Index (MD 1.49, 95% CI -3.21, 6.19; p > 0.05); Obstructive Sleep Apnea Index (MD 0.83, 95% CI -2.08, 3.75; p > 0.05); Hypopnea Index (MD -0.01, 95% CI -2.64, 2.63; p > 0.05); lowest oxygen saturation (MD 0.68, 95% CI -4.50, 5.86; p > 0.05); or sleep oxygen saturation >90% (MD 0.10, 95% CI -1.14, 1.34; p > 0.05). In conclusion, a single dose of 30 or 40 mg morphine does not have a significant effect on sleep or respiratory outcomes compared to placebo in patients with OSA, challenging the orthodoxy that opioids worsen OSA.

An assessment of opioids on respiratory depression in children with and without obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea is a risk factor for respiratory depression following opioid administration as well as opioid-induced hyperalgesia. Little is known on how obstructive sleep apnea status is associated with central ventilatory depression in pediatric surgical patients given a single dose of fentanyl.

METHODS

This was a single-center, prospective trial in children undergoing surgery requiring intubation and opioid administration. Sixty patients between the ages of 2-8 years presenting for surgery at Texas Children's Hospital were recruited. Twenty non-obstructive sleep apnea controls and 30 patients with moderate to severe obstructive sleep apnea met inclusion criteria. Following induction of general anesthesia and establishment of steady-state ventilation, participants received 1 mcg/kg intravenous fentanyl. Ventilatory variables (tidal volume, respiratory rate, end-tidal CO₂ , and minute ventilation) were assessed each minute for 10 min. The primary outcome was the extent of opioid-induced central ventilatory depression over time by obstructive sleep apnea status when compared with baseline values. Secondary aims assessed the impact of demographics and SpO₂ nadir on ventilatory depression.

RESULTS

We found no significant difference in percent decrease in respiratory rate (38.1% and 37.1%; p = .950), tidal volume (6.4% and 5.4%; p = .992), and minute ventilation (35.0 L/min and 35.0 L/min; p = .890) in control and obstructive sleep apnea patients, respectively. Both groups experienced similar percent increases in end-tidal CO₂ (4.0% vs. 2.2%; p = .512) in control and obstructive sleep apnea patients, respectively.

CONCLUSIONS

In pediatric surgical patients, obstructive sleep apnea status was not associated with significant differences in central respiratory depression following a single dose of fentanyl (1 mcg/kg). These findings can help determine safe opioid doses in future pediatric obstructive sleep apneapatients.

Dual mechanisms of opioid-induced respiratory depression in the inspiratory rhythm-generating network

The analgesic utility of opioid-based drugs is limited by the life-threatening risk of respiratory depression. Opioid-induced respiratory depression (OIRD), mediated by the μ-opioid receptor (MOR), is characterized by a pronounced decrease in the frequency and regularity of the inspiratory rhythm, which originates from the medullary preBötzinger Complex (preBötC). To unravel the cellular- and network-level consequences of MOR activation in the preBötC, MOR-expressing neurons were optogenetically identified and manipulated in transgenic mice in vitro and in vivo. Based on these results, a model of OIRD was developed in silico. We conclude that hyperpolarization of MOR-expressing preBötC neurons alone does not phenocopy OIRD. Instead, the effects of MOR activation are twofold: (1) pre-inspiratory spiking is reduced and (2) excitatory synaptic transmission is suppressed, thereby disrupting network-driven rhythmogenesis. These dual mechanisms of opioid action act synergistically to make the normally robust inspiratory rhythm-generating network particularly prone to collapse when challenged with exogenous opioids.

Perioperative Opioid Consumption is Not Reduced in Cyanotic Patients Presenting for the Fontan Procedure

Adequate pain control is a critical component of the perioperative approach to children undergoing repair of congenital heart disease (CHD). The impact of specific anatomic and physiologic disturbances on the management of analgesia has been largely unexplored at the present time. Studies in other pediatric populations have found an association between chronic hypoxemia and an increased sensitivity to the effects of opioid medications. The purpose of this retrospective study was to examine perioperative opioid administration and opioid-associated adverse effects in children undergoing surgical repair of CHD, with a comparison between patients with and without chronic preoperative cyanosis. Patients between the ages of 2 and 5 years whose tracheas were extubated in the operating room were included and were classified in the cyanotic group if they presented for the Fontan completion. The primary outcomes of interest were intraoperative and postoperative opioid administration. Secondary outcomes included pain scores and opioid-related side effects. The study cohort included 156 patients. Seventy-one underwent the Fontan procedure, twelve of which were fenestrated. Fontan patients received fewer opioids intraoperatively (11.33 µg/kg fentanyl equivalents versus 12.56 µg/kg, p = 0.03). However, there were no differences with regards to opioid consumption postoperatively and no correlation between preoperative oxygen saturation and total opioid administration. There were no differences between groups with regards to the respiratory rate nadir, postoperative pain scores, or the incidence of opioid-related side effects. In contrast to other populations with chronic hypoxemia exposure, children with cyanotic CHD did not appear to have increased sensitivity to the effects of opioid medications.

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.

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.

Neuronal mechanisms underlying opioid-induced respiratory depression: our current understanding

Opioid-induced respiratory depression (OIRD) represents the primary cause of death associated with therapeutic and recreational opioid use. Within the United States, the rate of death from opioid abuse since the early 1990s has grown disproportionally, prompting the classification as a nationwide "epidemic." Since this time, we have begun to unravel many fundamental cellular and systems-level mechanisms associated with opioid-related death. However, factors such as individual vulnerability, neuromodulatory compensation, and redundancy of opioid effects across central and peripheral nervous systems have created a barrier to a concise, integrative view of OIRD. Within this review, we bring together multiple perspectives in the field of OIRD to create an overarching viewpoint of what we know, and where we view this essential topic of research going forward into the future.

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.

Surgical management of obstructive sleep apnoea: A position statement of the Australasian Sleep Association. Respirology 2020;25:1292-1308. [PMID: 33190389 PMCID: PMC7839593 DOI: 10.1111/resp.13967]

Surgery for adult obstructive sleep apnoea (OSA) plays a key role in contemporary management paradigms, most frequently as either a second‐line treatment or in a facilitatory capacity. This committee, comprising two sleep surgeons and three sleep physicians, was established to give clarity to that role and expand upon its appropriate use in Australasia. This position statement has been reviewed and approved by the Australasian Sleep Association (ASA) Clinical Committee.

Classification and Detection of Breathing Patterns with Wearable Sensors and Deep Learning

Rapid assessment of breathing patterns is important for several emergency medical situations. In this research, we developed a non-invasive breathing analysis system that automatically detects different types of breathing patterns of clinical significance. Accelerometer and gyroscopic data were collected from light-weight wireless sensors placed on the chest and abdomen of 100 normal volunteers who simulated various breathing events (central sleep apnea, coughing, obstructive sleep apnea, sighing, and yawning). We then constructed synthetic datasets by injecting annotated examples of the various patterns into segments of normal breathing. A one-dimensional convolutional neural network was implemented to detect the location of each event in each synthetic dataset and to classify it as belonging to one of the above event types. We achieved a mean F1 score of 92% for normal breathing, 87% for central sleep apnea, 72% for coughing, 51% for obstructive sleep apnea, 57% for sighing, and 63% for yawning. These results demonstrate that using deep learning to analyze chest and abdomen movement data from wearable sensors provides an unobtrusive means of monitoring the breathing pattern. This could have application in a number of critical medical situations such as detecting apneas during sleep at home and monitoring breathing events in mechanically ventilated patients in the intensive care unit.

Chronic non-cancer pain and its association with healthcare use and costs among individuals with obstructive sleep apnea

Aim: To evaluate the impact of chronic non-cancer pain (CNCP) on healthcare use and costs among individuals diagnosed with obstructive sleep apnea (OSA). Materials & methods: Using the IQVIA PharMetrics^® Plus database, we identified individuals (18-64 years old) during 2007-2014, divided into two groups: OSA + CNCP versus OSA-only. Generalized linear models were used to analyze binary and count outcomes. Results: Relative to OSA-only controls, OSA + CNCP cases had increased odds for inpatient and emergency department visits and higher rates for physician office visits, non-physician outpatient visits, and prescription drug fills. Relative to controls, direct healthcare costs for cases were higher, primarily driven by inpatient and non-physician outpatient visit costs. Conclusion: Relative to OSA-only controls, OSA + CNCP cases displayed increased healthcare use and costs across all points of service.

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.

Concomitant benzodiazepine and opioids decrease sleep apnoea risk in chronic pain patients

Background

The concurrent use of sedating centrally acting drugs and opioids by chronic pain patients occurs routinely despite concerns of negative impacts on respiration during sleep. The effects of centrally acting drugs and opioids on sleep apnoea have not been well characterised. The objective of this study was to assess the effect of concomitant centrally acting drugs and opioids on the prevalence and severity of sleep apnoea in chronic pain patients.

Methods

We conducted a prospective cohort study at five chronic pain clinics. Each participant underwent an in-laboratory polysomnography and daily morphine milligram equivalents were calculated. Participants were grouped into centrally acting drugs and opioid users versus sole opioid users.

Results

Of the 332 consented participants, 204 underwent polysomnography and 120 (58.8%) had sleep apnoea (72% obstructive, 20% central, and 8% indeterminate sleep apnoea). Overall, 35% (71 of 204) were taking opioids alone, and 65% (133 of 204) were taking centrally acting drugs and opioids. There was a 69% decrease in the odds of having sleep apnoea (apnoea–hypopnoea index ≥5 events·h⁻¹) in participants taking benzodiazepine/opioids versus sole opioid users (OR 0.31, 95% CI:0.12–0.80, p=0.015). Additionally, concomitant benzodiazepine/opioids versus sole opioid use was associated with a decrease in respiratory arousal index scores (p=0.03). Mean overnight S_pO2 was approximately 1% lower in the concomitant benzodiazepine/opioids group versus sole opioid users (93.1±2.5 versus 94.4±2.1%, p=0.01).

Conclusion

In chronic pain patients on opioids, administration of certain benzodiazepine sedatives induced a mild respiratory depression but paradoxically reduced sleep apnoea risk and severity by increasing the respiratory arousal threshold.

There may be potential to reduce sleep apnoea risk and severity in specific chronic pain patients on opioids using certain benzodiazepine sedatives by selecting those with a low respiratory arousal threshold in whom sleep promotion may stabilise breathinghttps://bit.ly/2Zj4WX1

Glaucoma-associated pain results in mechanical sensitivity changes in dogs: A pilot study

PURPOSE

To explore the effects of chronic, uncontrolled glaucoma on pressure sensitivity in dogs before and after enucleation of the painful globe.

METHODS

Client-owned dogs undergoing enucleation for chronic glaucoma with no other sources of pain were enrolled. Normal dogs of similar breeds and skull morphology were enrolled as controls. Craniofacial ratio (CFR) and relative palpebral fissure width (RPFW) were assessed in all patients. Serial mechanical quantitative sensory testing (QST) was performed the day before surgery, and 14, 30, 60, and 120 days after surgery. QST consisted of electronic Von Frey (eVF), and blunt algometry (BA) performed above and below the nonglaucomatous eye, the metacarpus, and metatarsus. Cochet-Bonnet esthesiometry (CB) was also performed on the remaining eye.

RESULTS

Twelve dogs (6 per group) were included. Compared to baseline values, sensitivity tended to decrease over time (increased thresholds) in treatment dogs while it stayed constant or increased slightly in control dogs. The difference in change from baseline sensitivity between control and treatment groups was significant at day 120 using BA at supraorbital (P = .0153), infraorbital (P = .0209), and metacarpal sites (P = .007) and overall (P = .0470). This divergence was also significant using CB (P = .0470) on the opposite cornea. As patient CFR and RPFWV increased, both eVF (P = .005-.023) and BA (P = .004-.041) increased.

CONCLUSIONS

Sensitivity to mechanical stimuli decreased both locally and at remote sites in dogs following enucleation for painful chronic glaucoma. Cranial conformation is associated with differences in sensitivity.

Effects of Intraoperative Ketamine on Post-Operative Recovery in Obstructive Sleep Apnea Patients: A Case-Control Study

Objective

To evaluate the post-operative outcomes of patients with obstructive sleep apnea (OSA) given intraoperative ketamine.

Design: case-control study

A total of 574 patients (287 received ketamine and 287 were matched controls) diagnosed with OSA and body mass index (BMI) > 30 who received general anesthesia were included in this study. Patients given intraoperative ketamine were matched (1:1) with those who did not receive ketamine for age, gender, BMI, ethnicity, anesthesia time, intraoperative fentanyl dose, ketamine dose, and surgery type. A sub-analysis was performed based on the dose of ketamine administered and also on the surgery type. Measured outcomes include post-operative pain scores, post-operative opioid requirements, respiratory status, oxygen use, and duration post-operatively.

Results

Intraoperative ketamine use did not decrease pain scores or post-operative opioid use when compared with the control (no intraoperative ketamine) group. Patients who received high-dose ketamine had significantly higher post-operative pain scores (p=0.048) while in the post-anesthesia care unit (PACU) and required supplemental oxygen for a longer period of time (p = 0.030), pain scores were not significant for patients who underwent orthopedic/spine procedures (p = 0.074), and high-dose ketamine group patients who underwent orthopedic/spine surgery required significantly more opioids in the PACU (p = 0.031). Among patients who received low-dose ketamine, those who underwent head, ear, nose, and throat surgery required significantly more opioids in PACU (p = 0.022).

Conclusions

Low-dose intraoperative ketamine did not decrease pain scores or post-operative opioid use significantly and did not improve standard respiratory recovery parameters for OSA patients after surgery. Neither low- nor high-dose ketamine demonstrated the anticipated benefits of low pain scores and reduced post-operative opioid use. These outcomes will differ depending on the surgery type and dose of ketamine used.

Experience and sleep-dependent synaptic plasticity: from structure to activity

Synaptic plasticity is important for learning and memory. With increasing evidence linking sleep states to changes in synaptic strength, an emerging view is that sleep promotes learning and memory by facilitating experience-induced synaptic plasticity. In this review, we summarize the recent progress on the function of sleep in regulating cortical synaptic plasticity. Specifically, we outline the electroencephalogram signatures of sleep states (e.g. slow-wave sleep, rapid eye movement sleep, spindles), sleep state-dependent changes in gene and synaptic protein expression, synaptic morphology, and neuronal and network activity. We highlight studies showing that post-experience sleep potentiates experience-induced synaptic changes and discuss the potential mechanisms that may link sleep-related brain activity to synaptic structural remodelling. We conclude that both synapse formation or strengthening and elimination or weakening occur across sleep. This sleep-dependent synaptic plasticity plays an important role in neuronal circuit refinement during development and after learning, while sleep disorders may contribute to or exacerbate the development of common neurological diseases. This article is part of the Theo Murphy meeting issue 'Memory reactivation: replaying events past, present and future'.

Contribution of Baroreceptor Function to Pain Perception and Perioperative Outcomes

Baroreceptors are mechanosensitive elements of the peripheral nervous system that maintain homeostasis by coordinating physiologic responses to external and internal stimuli. While it is recognized that carotid and cardiopulmonary baroreceptor reflexes modulate autonomic output to mitigate excessive fluctuations in arterial blood pressure and to maintain intravascular volume, increasing evidence suggests that baroreflex pathways also project to key regions of the central nervous system that regulate somatosensory, somatomotor, and central nervous system arousal. In addition to maintaining autonomic homeostasis, baroreceptor activity modulates the perception of pain, as well as neuroimmune, neuroendocrine, and cognitive responses to physical and psychologic stressors. This review summarizes the role that baroreceptor pathways play in modulating acute and chronic pain perception. The contribution of baroreceptor function to postoperative outcomes is also presented. Finally, methods that enhance baroreceptor function, which hold promise in improving postoperative and pain management outcomes, are presented.

Opioid-Related Sleep-Disordered Breathing: An Update for Clinicians

Opioids are an effective treatment for patients with intractable pain. Long-term administration of opioids for pain relief is being delivered by an increasing number of medical providers in the United States including primary care physicians and nonspecialists. One common complication of chronic opioid use is sleep-disordered breathing which can result in various morbidities as well as an increase in all-cause mortality. It is important for providers to understand the relationship between opioids and sleep-disordered breathing as well as methods to improve diagnosis and strategies for treatment. This review aims to update clinicians on the mechanism, diagnosis, and treatment of opioid-related sleep-disordered breathing in order to improve the quality of care for patients with chronic pain.

[CME: Nacht-zu-Nacht-Variabilität der obstruktiven Schlafapnoe]

Die aktuellen Leitlinien empfehlen, unkomplizierte Patientinnen und Patienten mit Verdacht auf obstruktive Schlafapnoe (OSA) mittels einer einzigen Schlafuntersuchung zu diagnostizieren. Eine kürzlich veröffentlichte Meta-Analyse konnte hingegen eine ausgeprägte intra-individuelle Variabilität respiratorischer Parameter von Nacht zu Nacht zeigen. Wir präsentieren den Fall eines 76-jährigen Patienten mit Verdacht auf OSA, der innerhalb von 13 Wochen sechs Schlafuntersuchungen unterzogen wurde. Hierbei präsentierte sich eine relevante Variabilität des AHI zwischen 1,1 und 43,1/h. Es konnten keine relevanten Unterschiede betreffend Gewicht, Alkoholkonsum, Medikation und Begleiterkrankungen zwischen den Schlafuntersuchungen festgestellt werden. Aufgrund fehlender subjektiver Wirksamkeit wurde die CPAP-Therapie nach einem Jahr gestoppt. Die ausgeprägte Nacht-zu-Nacht-Variabilität respiratorischer Parameter stellt eine akkurate OSA-Diagnostik mittels einer einzelnen Schlafuntersuchung in Frage.

Potential Cytochrome P450 Drug-Drug Interaction Among Adult and Adolescent Patients Undergoing Tonsillectomy

Objective

To assess the frequency of potential drug-drug interactions affecting cytochrome P450 (CYP)–mediated metabolism of opioids among adult and adolescent patients who underwent adenotonsillectomy.

Study Design

Retrospective chart review.

Setting

Tertiary care university hospital.

Patients and Methods

A retrospective review was conducted of 279 patients who underwent adenotonsillectomy at the University of Rochester. The discharge medication list was reviewed for all patients, and their postoperative medications were compared with a reference list published by the Food and Drug Administration and the University of Indiana’s Department of Clinical Pharmacology (Flockhart Table) to determine whether CYP-inducing or CYP-inhibiting medication was present.

Results

Out of 279 patients, 197 different medications were taken postoperatively. Approximately 70% of patients were taking 2 medications in addition to the standard postoperative analgesics (acetaminophen, hydrocodone, oxycodone, morphine, and/or ibuprofen). The 5 most commonly prescribed medications excluding the posttonsillectomy medications were oral contraceptives, ondansetron, amoxicillin, albuterol, and methylprednisolone. Four percent of patients were taking a medication that inhibits CYP3A4; <1% were taking a medication that induces CYP3A4; and 15% were taking a medication that inhibits CYP2D6.

Conclusions

Nearly 20% of the patients in this cohort were taking a medication that may alter opioid metabolism through induction or inhibition of CYP3A4 or CYP2D6. Some of these interactions have the potential to be more clinically relevant than others, particularly interactions that can lead to enhanced toxicity of opioids due to accumulation of active metabolites.