Opioids and obstructive sleep apnea

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

CITATION

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

Designer Receptors Exclusively Activated by Designer Drugs Approach to Treatment of Sleep-disordered Breathing

Rationale: Obstructive sleep apnea is recurrent upper airway obstruction caused by a loss of upper airway muscle tone during sleep. The main goal of our study was to determine if designer receptors exclusively activated by designer drugs (DREADD) could be used to activate the genioglossus muscle as a potential novel treatment strategy for sleep apnea. We have previously shown that the prototypical DREADD ligand clozapine-N-oxide increased pharyngeal diameter in mice expressing DREADD in the hypoglossal nucleus. However, the need for direct brainstem viral injections and clozapine-N-oxide toxicity diminished translational potential of this approach, and breathing during sleep was not examined.Objectives: Here, we took advantage of our model of sleep-disordered breathing in diet-induced obese mice, retrograde properties of the adeno-associated virus serotype 9 (AAV9) viral vector, and the novel DREADD ligand J60.Methods: We administered AAV9-hSyn-hM3(Gq)-mCherry or control AAV9 into the genioglossus muscle of diet-induced obese mice and examined the effect of J60 on genioglossus activity, pharyngeal patency, and breathing during sleep.Measurements and Main Results: Compared with control, J60 increased genioglossus tonic activity by greater than sixfold and tongue uptake of 2-deoxy-2-[¹⁸F]fluoro-d-glucose by 1.5-fold. J60 increased pharyngeal patency and relieved upper airway obstruction during non-REM sleep.Conclusions: We conclude that following intralingual administration of AAV9-DREADD, J60 can activate the genioglossus muscle and improve pharyngeal patency and breathing during sleep.

Intranasal Leptin Prevents Opioid-induced Sleep-disordered Breathing in Obese Mice

Respiratory depression is the main cause of morbidity and mortality associated with opioids. Obesity increases opioid-related mortality, which is mostly related to comorbid obstructive sleep apnea. Naloxone, a μ-opioid receptor blocker, is an effective antidote, but it reverses analgesia. Like humans with obesity, mice with diet-induced obesity hypoventilate during sleep and develop obstructive sleep apnea, which can be treated with intranasal leptin. We hypothesized that intranasal leptin reverses opioid-induced sleep-disordered breathing in obese mice without decreasing analgesia. To test this hypothesis, mice with diet-induced obesity were treated with morphine at 10 mg/kg subcutaneously and with leptin or placebo intranasally. Sleep and breathing were recorded by barometric plethysmography, and pain sensitivity was measured by the tail-flick test. Excitatory postsynaptic currents were recorded in vitro from hypoglossal motor neurons after the application of the μ-opioid receptor agonist [D-Ala², N-MePhe⁴, Gly-ol]-enkephalin and leptin. Morphine dramatically increased the frequency of apneas and greatly increased the severity of hypoventilation and obstructive sleep apnea. Leptin decreased the frequency of apneas, improved obstructive sleep apnea, and completely reversed hypoventilation, whereas morphine analgesia was enhanced. Our in vitro studies demonstrated that [D-Ala², N-MePhe⁴, Gly-ol]-enkephalin reduced the frequency of excitatory postsynaptic currents in hypoglossal motoneurons and that application of leptin restored excitatory synaptic neurotransmission. Our findings suggest that intranasal leptin may prevent opioid respiratory depression during sleep in patients with obesity receiving opioids without reducing analgesia.

Study of the relation between medial orbitofrontal artery and anterior skull base performed by computed tomography angiography

BACKGROUND

The aims of this study were to analyze the relationships between the medial orbitofrontal artery (MOFA) and the anterior skull base (ASB) including anatomical endonasal landmarks using computed tomography angiography (CTA).

METHODS

We studied 52 CTAs using OsiriX software. All CTAs were placed in the same anatomical position. MOFA was identified in the sagittal and coronal plane and its correlation with ASB was analyzed. The distance between the MOFA and landmarks for endonasal surgery were obtained, determining the high risk areas for its injury.

RESULTS

After arising from the anterior cerebral artery, the MOFA dives inferiorly towards the ASB, close to the midline (average distance of 1.5 mm), approaching the planum sphenoidale (average distance of 1.8 mm) and then ascends away from the ASB as it runs anteriorly, with an average distance of 4.4 mm in the region of the anterior wall of the sphenoid sinus and 12 mm in the region of the anterior ethmoid artery.

CONCLUSIONS

The MOFA has an intimate relationship with the ASB and nasal cavity; the regions with the highest risk of surgical trauma are between the posterior ethmoid and the planum sphenoidale.

Neurostimulation Treatment of OSA

Over the past 30 years, hypoglossal nerve stimulation has moved through a development pathway to become a viable treatment modality for patients with OSA. Initial pilot studies in animals and humans laid the conceptual foundation for this approach, leading to the development of fully implantable stimulating systems for therapeutic purposes. These devices were then shown to be both safe and efficacious in feasibility studies. One such closed-loop stimulating device was found to be effective in treating a limited spectrum of apneic patients and is currently approved by the US Food and Drug Administration for this purpose. Another open-loop stimulating system is currently being rigorously tested in a pivotal trial. Collectively, clinical trials of hypoglossal nerve stimulating systems have yielded important insights that can help optimize therapeutic responses to hypoglossal nerve stimulation. These insights include specific patient selection criteria and methods for delivering stimulation to specific portions of the hypoglossal nerve and/or genioglossus muscle. New approaches for activating efferent and afferent motor pathways are currently in early-stage laboratory development and hold some long-term promise as a novel therapy.

Chemogenetic stimulation of the hypoglossal neurons improves upper airway patency

Obstructive sleep apnea (OSA) is characterized by recurrent upper airway obstruction during sleep. OSA leads to high cardiovascular morbidity and mortality. The pathogenesis of OSA has been linked to a defect in neuromuscular control of the pharynx. There is no effective pharmacotherapy for OSA. The objective of this study was to determine whether upper airway patency can be improved using chemogenetic approach by deploying designer receptors exclusively activated by designer drug (DREADD) in the hypoglossal motorneurons. DREADD (rAAV5-hSyn-hM3(Gq)-mCherry) and control virus (rAAV5-hSyn-EGFP) were stereotactically administered to the hypoglossal nucleus of C57BL/6J mice. In 6-8 weeks genioglossus EMG and dynamic MRI of the upper airway were performed before and after administration of the DREADD ligand clozapine-N-oxide (CNO) or vehicle (saline). In DREADD-treated mice, CNO activated the genioglossus muscle and markedly dilated the pharynx, whereas saline had no effect. Control virus treated mice showed no effect of CNO. Our results suggest that chemogenetic approach can be considered as a treatment option for OSA and other motorneuron disorders.

Study of the association between human leukocyte antigens (HLA) and pemphigus vulgaris in Brazilian patients

BACKGROUND

Pemphigus vulgaris is a mucocutaneous blistering autoimmune disease that manifests as painful blisters or erosions on the skin and/or mucosal surfaces. IgG autoantibodies target desmoglein, playing a major role in disease pathogenesis. Genetic predisposal to pemphigus vulgaris, especially the HLA DR and DQ alleles, has been known since the 1980s. The unique constitution of the Brazilian population favors exploratory genetic studies.

METHODS

The study group included 51 patients with a confirmed diagnosis of pemphigus vulgaris from a tertiary hospital in Sao Paulo city, Sao Paulo, southeast Brazil. DNA was extracted from peripheral blood, and HLA A, B, C, DR, and DQ typing was performed. The control group was composed of a database of 297 deceased donors from the city of São Paulo typed with the same method. The statistical significance level was adjusted using the Bonferroni correction depending on the phenotypic frequencies evaluated for HLA A, HLA B, HLA C, HLA DRB1, DQA1, and HLA DQB1.

RESULTS

The alleles HLA-B*57, HLA-C*15, HLA-DRB1*04:02, HLA-DRB1*08:04, HLA-DRB1*14:01, DQA1*03:01, DQB1*03:02, and DQB1*05:03 were associated with susceptibility. Alleles HLA DRB1*04:02 and HLA-DRB1*14:01 and their respective haplotypes DRB1*04-DQA1*03:01-DQB1*03:02, and DRB1*14-DQA1*01:01-DQB1*05:03 conferred a risk of the disease.

CONCLUSIONS

The DRB1*04:02 and DQB1*05:03 alleles are associated with pemphigus vulgaris in our study as well as in various populations. The association with HLA-DRB1*08:04 in our study was confirmed to be specific to this allele and not to linkage disequilibrium to any adjacent gene. The association between HLA-B*57 and pemphigus vulgaris is reported for the first time in the present study.

Juvenile angiofibroma: major and minor complications of preoperative embolization

INTRODUCTION

Juvenile angiofibromas (JA) are highly vascular, benign tumours for which surgery is the treatment of choice. In most services, embolisation is performed prior to resection. Nevertheless, there are few data on the complications of preoperative embolisation for JA.

AIM

To describe major and minor complications of preoperative embolisation in a 32-year experience of patients undergoing surgical resection of JA at a tertiary hospital.

METHODS

Retrospective chart review study of 170 patients who underwent surgical resection of JA at a tertiary hospital between September 1976 and July 2008.

RESULTS

All patients were male. Age ranged from 9 to 26 years. Ninety-one patients had no complications after embolisation. Overall, 105 complication events occurred of which four major and 101 minor.

CONCLUSION

In our series, preoperative embolisation for JA produced no irreversible complications and no aesthetic or functional sequelae. The vast majority of complications were transient and amenable to clinical management.

Individually customized implants for laryngoplasty--are they possible?

OBJECTIVE

To standardize the design of individually fitted implants based on computed tomographic (CT) images for use in medialization laryngoplasty without intraoperative voice monitoring.

STUDY DESIGN

Prospective tomographic and anatomical experimental study of 10 human cadaveric larynges.

METHODS

CT scans of 10 excised human larynges were analyzed to define the shape and size of ideal implants for medialization laryngoplasty. Silicone implants were designed according to CT parameters and used in simulated laryngoplasties in the laryngeal specimens. The efficacy of each implant in providing adequate medialization of the vocal fold was evaluated.

RESULTS

Diverse shapes and sizes of implants were obtained, reflecting variations in laryngeal anatomy. The implants enabled regular medialization of the entire extent of the free border of the vocal fold, including its posterior aspect. Medialization was considered adequate in all cases.

CONCLUSIONS

This method proved to be a simple and efficient way to design individualized implants for medialization laryngoplasty, regardless of the size and shape of the larynx.

LEVEL OF EVIDENCE

Not available.

Study of the nasoseptal flap for endoscopic anterior cranial base reconstruction

OBJECTIVES/HYPOTHESIS

Measure the dimensions of the nasoseptal (NS) flap and the anterior skull base (ASB) defect. Verify whether the flap is sufficient to cover the defect. Study the anatomy of the septal artery (SA).

STUDY DESIGN

Anatomical and radiological study.

METHODS

After endoscopic craniofacial resection, sufficiency of the flap to cover the ASB defect was assessed. The SA was dissected. The number of branches in the pedicle and the distance between the artery and the sphenoid ostium were noted. Radiologic study analyzing CT scans of 30 patients for comparison among measurements of the NS flap and the ASB defect was performed.

RESULTS

In all cases the flap was sufficient to cover the ASB. Two branches of the SA were found in the pedicle in 71.4%. The distance between the SA and the sphenoid ostium was 9.3 mm. The reconstruction area of the flap (17.12 cm(2) ) was larger than the defect area (8.64 cm(2) ) (P < .001). The difference between the superior length of the flap and the anterior-posterior distance of the defect was ≤ 5 mm in 26.7%. Comparison between the anterior flap width and the anterior defect width revealed that in 33% the difference was ≤ 5 mm.

CONCLUSIONS

The dimensions of NS flap are sufficient to cover completely the ASB defect. The anterior edge of the defect presents increased risk for failure in coverage. Additional width adding the nasal floor mucosa to the flap is important to decrease the risk of gap in the anterior orbit-orbit defect. It is more common to find two branches of the SA in the pedicle.

Endonasal endoscopic exposure of the internal carotid artery: an anatomical study

OBJECTIVES/HYPOTHESIS

The aim of this work was to define the anatomical landmarks, limitations, and difficulties of obtaining internal carotid artery (ICA) exposure via endonasal endoscopic approaches (EEA).

STUDY DESIGN

Cadaveric descriptive study.

METHODS

The ICA was dissected via EEA in 10 cadaveric specimens (20 sides) prepared with intravascular injections of colored silicone. We carried the ICA dissection from the cavernous to the distal parapharyngeal segments through a transpterygoid corridor.

RESULTS

The transpterygoid approach provided adequate exposure of the lacerum and horizontal petrous ICA. Additional exposure of the ICA and the infrapetrous area required resection of the eustachian tube (ET) and the fibrocartilaginous tissue of the foramen lacerum after a medial maxillectomy and resection of the pterygoid plates. The main anatomical landmarks to the corresponding ICA segment include: the vidian nerve that points to the lacerum and horizontal segments, the mandibular nerve (V3) that heralds the petrous segment, the foramen ovale and the ET that signal toward the carotid canal, and the posterior trunk of the mandibular nerve (V3) and the ET that mark the parapharyngeal segment.

CONCLUSIONS

EEAs provide access to the ICA from its cavernous to the distal parapharyngeal segments. A stepwise approach is critical to its exposure and control. Surgeons must be aware of its frequently tortuous three-dimensional course and the intimate relation of the vessel to the carotid canal and the cartilage of the foramen lacerum.

The presence of a vocal ligament in fetuses: a histochemical and ultrastructural study

Although it is currently believed that the vocal ligament of humans undergoes considerable development postnatally, there is no consensus as to the age at which it first emerges. In the newborn infant, the lamina propria has been described as containing a sparse collection of relatively unorganized fibres. In this study we obtained larynges from autopsy of human fetuses aged 7-9 months and used light and electron microscopy to study the collagenous and elastic system fibres in the lamina propria of the vocal fold. Collagen fibres were viewed using the Picrosirius polarization method and elastic system fibres were stained using Weigert's resorcin-fuchsin after oxidation with oxone. The histochemical and electron microscopic observations were consistent, showing collagen populations with an asymmetric distribution across different compartments of the lamina propria. In the central region, the collagen appeared as thin, weakly birefringent, greenish fibres when viewed using the Picrosirius polarization method, whereas the superficial and deep regions contained thick collagen fibres that displayed a strong red or yellow birefringence. These findings suggest that the thin fibres in the central region consist mainly of type III collagen, whereas type I collagen predominates in the superficial and deep regions, as has been reported in studies of adult vocal folds. Similarly, elastic system fibres showed a differential distribution throughout the lamina propria. Their distribution pattern was complementary to that of collagen fibres, with a much greater density of elastic fibres apparent in the central region than in the superficial and deep regions. This distribution of collagen and elastic fibres in the fetal vocal fold mirrors that classically described for the adult vocal ligament, suggesting that a vocal ligament has already begun to develop by the time of birth. The apparently high level of organization of connective tissue components in the newborn is in contrast to current hypotheses that argue that the mechanical stimuli of phonation are essential to the determination of the layered structure of the lamina propria and suggests that genetic factors may play a more significant role in the development of the vocal ligament than previously believed.

Tissue maturation correlating to clinical manifestations in juvenile angiofibroma

OBJECTIVES

Juvenile nasopharyngeal angiofibroma is a rare benign tumor that affects young male patients and shows a characteristic development from its origin. It is not a true neoplasm, but shows features of vascular processes, developing into a more fibrous condition. The aim of this study was to correlate the clinical manifestations and the histologic findings of the tumor.

METHODS

Thirty-six patients without previous treatment were studied. We correlated the incidence and duration of the clinical manifestations (nasal obstruction, epistaxis, nasal and/or pharyngeal tumor, and facial deformity) and morphometric histologic analyses of the central region of the tumor (number, caliber, and presence of muscle cells in the vessel wall, and tissue maturity and cellularity).

RESULTS

The duration of nasal obstruction, the presence of nasal and/or pharyngeal tumor, and facial deformity were significantly correlated with the number of vessels, the tissue maturation, and the cellularity of the tumor. Epistaxis showed a strong correlation with the presence of muscle fibers in the vessels.

CONCLUSIONS

There are correlations between the duration of the clinical manifestations and histologic maturation in the central portion of the tumor.

Juvenile nasopharyngeal angiofibroma: the routes of invasion

The juvenile nasopharyngeal angiofibroma has a characteristic growth in all directions from its origin. However, the extensions of the tumor seem to be independent, each one with distinct behavior. The aim of this study is to analyze the preferential direction and routes of JNA growth, as well as its correlation with the patient's age. We analyzed 33 patients without any previous treatment, attempting to the extension and routes of tumor's growth (CT scan), and its correlation with the patient's age. The sphenopalatine foramen region was affected in all cases. From this point, a growth towards several routes with a different rhythm was noted, determining variable configurations to the tumor. The lateral and superior growths were the most frequent. The expansion into the pterygopalatine fossa was very frequent and could involve important anatomical structures, determining higher morbidity. Three sites were invaded through more than one route: pterygoid fossa, middle cranial fossa and maxillary sinus. There was no significant correlation between invasion route and patient's age. However, considering the age, there was a concomitance between tumor development and facial growth by "displacement". We discuss this condition, suggesting an explanation to the tumor invasion and expansion inside the pterygopalatine fossa.

Descending necrotizing mediastinitis: a retrospective surgical experience

OBJECTIVE

Descending necrotizing mediastinitis (DNM) is a primary complication of cervical or odontogenical infections that can spread to the mediastinum through the anatomic cervical spaces. We reviewed the last 10 years of our surgical experience in DNM and commented on early diagnosis and aggressive surgical treatment in these patients.

METHODS

Five males (71%) and two females (29%), mean age 34 years, with DNM, were surgically treated. Primary oropharyngeal infection occurred in three (43%) and odontogenic abscess in four (57%) patients. All had serious cervical and mediastinal infections with severe respiratory and hemodynamic repercussions, i.e. bacteremia, systemic arterial hypotension and obnubilation. Diagnosis was confirmed by computerized chest tomography.

RESULTS

All patients underwent surgical drainage of the cervical region by bilateral transverse cervicotomy with debridement of the necrotic and infected tissues, associating ample mediastinal drainage with or without thoracotomy. Six patients (86%) evolved well and were discharged after a mean of 35 days. Two patients (29%) required reoperation due to local surgical complications: empyema and dehiscence of the sternum. One patient (14%) died on the second postoperative (p.o.) day due to renal and respiratory insufficiency. Cultures of DNM showed the development of associated aerobic and anaerobic flora in 71% of the operated patients and only aerobic in 29%.

CONCLUSION

Early diagnosis by CAT scan of the neck and thorax aids in rapid indication of a surgical approach of DNM. Performing ample cervicotomy with mediastinal drainage generally associated with thoracotomy can significantly reduce the mortality rate for this condition to 14%.

Spontaneous Cervical Hematoma: A Report of Two Cases

Cervical hematomas are generally associated with trauma, surgery, and tumors. Although they are rare, they can be life-threatening because they put the patient at risk for great-vessel compression and upper airway obstruction.

We describe two cases of spontaneous cervical hematoma— one in an 81-year-old man and the other in a 30-year-old woman. The man reported dysphonia, dysphagia, and neck swelling of 5 hours’ duration. He had been taking 100 mg/day of aspirin for a cardiovascular condition. Examination revealed that the man had polycythemia vera. The woman was found to have neck ache, odynophagia, and cervical ecchymosis; portal hypertension, schistosomiasis, and blood dyscrasia were also found. Both patients denied trauma. A suspected diagnosis of cervical hematoma was confirmed by computed tomography, and treatment was instituted. The hematomas resolved in about 2 weeks.

The treatment of cervical hematoma is controversial, although it is agreed that the evaluation of upper airway obstruction and its permeability is mandatory. Surgical treatment is generally reserved for complicated cases because of the risk of infection or bleeding.

Spontaneous cervical hematoma: a report of two cases

Cervical hematomas are generally associated with trauma, surgery, and tumors. Although they are rare, they can be life-threatening because they put the patient at risk for great-vessel compression and upper airway obstruction. We describe two cases of spontaneous cervical hematoma--one in an 81-year-old man and the other in a 30-year-old woman. The man reported dysphonia, dysphagia, and neck swelling of 5 hours' duration. He had been taking 100 mg/day of aspirin for a cardiovascular condition. Examination revealed that the man had polycythemia vera. The woman was found to have neck ache, odynophagia, and cervical ecchymosis; portal hypertension, schistosomiasis, and blood dyscrasia were also found. Both patients denied trauma. A suspected diagnosis of cervical hematoma was confirmed by computed tomography, and treatment was instituted. The hematomas resolved in about 2 weeks. The treatment of cervical hematoma is controversial, although it is agreed that the evaluation of upper airway obstruction and its permeability is mandatory. Surgical treatment is generally reserved for complicated cases because of the risk of infection or bleeding.

Microbiology of sinusitis in patients undergoing bone marrow transplantation

As a result of increasing use of bone marrow transplantation and new cytotoxic chemotherapy, more patients have become susceptible to sinus disease caused by unusual organisms. Sinusitis caused by fungi and gram-negative bacteria can be difficult to treat, may lead to severe complications, and should be managed promptly in the bone marrow transplant patient. Here we present the results of 41 cultures of the paranasal sinuses obtained from 18 bone marrow transplant patients in whom sinusitis developed. The most common agents were gram-negative bacteria (56.7%), followed by gram-positive bacteria (26.7%) and fungi (16.6%). In 13 samples the cultures were negative. Nasal cultures were performed ipsilateral to the sinus drained in 28 cases. Concordance was obtained in only 5 (17.8%) samples. The antibiogram of the isolated agents from the maxillary sinuses in this series revealed that the most efficient antibiotics were those that covered gram-negative bacteria. Treatment was usually prolonged in these patients, and different antibiotics were necessary to clear infections from the sinuses. In conclusion, treating sinusitis in bone marrow transplant patients may be challenging. Considerations about the microbiology and antibiogram susceptibilities of this specific population should be kept in mind when dealing with such cases.