-
Clinics in Geriatric Medicine Aug 2021Undiagnosed and untreated obstructive sleep apnea (OSA) is associated with health comorbidities and negatively affects quality of life. Alternative treatments should be... (Review)
Review
Undiagnosed and untreated obstructive sleep apnea (OSA) is associated with health comorbidities and negatively affects quality of life. Alternative treatments should be considered in patients who are unable to tolerate or benefit from positive airway pressure treatment. When properly indicated, positional devices, oral appliances, airway surgery, and hypoglossal nerve stimulation have been shown to be effective in treating OSA. Hypoglossal nerve stimulation is a successful second-line treatment with low associated morbidity and complication rate.
Topics: Aged; Electric Stimulation Therapy; Humans; Hypoglossal Nerve; Implantable Neurostimulators; Mandibular Advancement; Phrenic Nerve; Quality of Life; Sleep Apnea, Obstructive; Treatment Outcome
PubMed: 34210448
DOI: 10.1016/j.cger.2021.04.005 -
Respiratory Physiology & Neurobiology Jul 2019Acute intermittent hypoxia (AIH) elicits distinct mechanisms of phrenic motor plasticity initiated by brainstem neural network activation versus local (spinal) tissue... (Review)
Review
Acute intermittent hypoxia (AIH) elicits distinct mechanisms of phrenic motor plasticity initiated by brainstem neural network activation versus local (spinal) tissue hypoxia. With moderate AIH (mAIH), hypoxemia activates the carotid body chemoreceptors and (subsequently) brainstem neural networks associated with the peripheral chemoreflex, including medullary raphe serotonergic neurons. Serotonin release and receptor activation in the phrenic motor nucleus then elicits phrenic long-term facilitation (pLTF). This mechanism is independent of tissue hypoxia, since electrical carotid sinus nerve stimulation elicits similar serotonin-dependent pLTF. In striking contrast, severe AIH (sAIH) evokes a spinal adenosine-dependent, serotonin-independent mechanism of pLTF. Spinal tissue hypoxia per se is the likely cause of sAIH-induced pLTF, since local tissue hypoxia elicits extracellular adenosine accumulation. Thus, any physiological condition exacerbating spinal tissue hypoxia is expected to shift the balance towards adenosinergic pLTF. However, since these mechanisms compete for dominance due to mutual cross-talk inhibition, the transition from serotonin to adenosine dominant pLTF is rather abrupt. Any factor that compromises spinal cord circulation will limit oxygen availability in spinal cord tissue, favoring a shift in the balance towards adenosinergic mechanisms. Such shifts may arise experimentally from treatments such as carotid denervation, or spontaneous hypotension or anemia. Many neurological disorders, such as spinal cord injury or stroke compromise local circulatory control, potentially modulating tissue oxygen, adenosine levels and, thus, phrenic motor plasticity. In this brief review, we discuss the concept that local (spinal) circulatory control and/or oxygen delivery regulates the relative contributions of distinct pathways to phrenic motor plasticity.
Topics: Adenosine; Animals; Cervical Cord; Humans; Hypoxia; Neuronal Plasticity; Oxygen; Phrenic Nerve; Respiratory Physiological Phenomena; Serotonin; Synaptic Potentials
PubMed: 30639504
DOI: 10.1016/j.resp.2019.01.004 -
Phrenic Nerve Stimulator Placement via the Cervical Approach: Technique and Anatomic Considerations.Operative Neurosurgery (Hagerstown, Md.) Aug 2021Diaphragmatic pacing via phrenic nerve stimulation can help improve breathing and facilitate mechanical ventilation weaning in patients with respiratory failure...
BACKGROUND
Diaphragmatic pacing via phrenic nerve stimulation can help improve breathing and facilitate mechanical ventilation weaning in patients with respiratory failure secondary to brainstem injury, high cervical spinal cord injury, or congenital central hypoventilation. Devices can be placed utilizing several techniques; however, nuances regarding placement are not well published.
OBJECTIVE
To describe our experience with phrenic nerve stimulator placement via the cervical approach with a focus on surgical anatomy, variations, and technique.
METHODS
Placement of phrenic nerve stimulator via a cervical approach is described in detail.
RESULTS
Successful placement of phrenic nerve stimulator without complication.
CONCLUSION
The cervical approach for the placement of a phrenic nerve stimulator is a safe and effective option for patients. Detailed knowledge of anatomy and anatomic variations is required. Potential advantages and disadvantages are discussed.
Topics: Diaphragm; Humans; Hypoventilation; Phrenic Nerve; Sleep Apnea, Central; Spinal Cord Injuries
PubMed: 33677605
DOI: 10.1093/ons/opab047 -
Multimedia Manual of Cardiothoracic... Aug 2021The authors demonstrate a video-assisted thoracoscopic surgical technique for diaphragmatic plication, which is used to treat acquired diaphragmatic paralysis resulting...
The authors demonstrate a video-assisted thoracoscopic surgical technique for diaphragmatic plication, which is used to treat acquired diaphragmatic paralysis resulting from injury to the phrenic nerve. The objective of the surgical procedure is to return the abdominal contents to their normal position and restore optimal lung expansion by reducing the size of the diaphragmatic surface. Successful diaphragmatic plication improves lung function, reduces dyspnea, and restores quality of life.
Topics: Diaphragm; Humans; Phrenic Nerve; Quality of Life; Respiratory Paralysis; Thoracic Surgery, Video-Assisted
PubMed: 35616985
DOI: 10.1510/mmcts.2021.043 -
Journal of Ultrasound in Medicine :... Feb 2022The diaphragm, the principle muscle of inspiration, is an under-recognized contributor to respiratory disease. Dysfunction of the diaphragm can occur secondary to lung... (Review)
Review
The diaphragm, the principle muscle of inspiration, is an under-recognized contributor to respiratory disease. Dysfunction of the diaphragm can occur secondary to lung disease, prolonged ventilation, phrenic nerve injury, neuromuscular disease, and central nervous system pathology. In light of the global pandemic of coronavirus disease 2019 (COVID-19), there has been growing interest in the utility of ultrasound for evaluation of respiratory symptoms including lung and diaphragm sonography. Diaphragm ultrasound can be utilized to diagnose diaphragm dysfunction, assess severity of dysfunction, and monitor disease progression. This article reviews diaphragm and phrenic nerve ultrasound and describes clinical applications in the context of COVID-19.
Topics: COVID-19; Diaphragm; Humans; Phrenic Nerve; SARS-CoV-2; Ultrasonography
PubMed: 33772850
DOI: 10.1002/jum.15706 -
Anesthesiology May 2022Strong spontaneous inspiratory efforts can be difficult to control and prohibit protective mechanical ventilation. Instead of using deep sedation and neuromuscular...
BACKGROUND
Strong spontaneous inspiratory efforts can be difficult to control and prohibit protective mechanical ventilation. Instead of using deep sedation and neuromuscular blockade, the authors hypothesized that perineural administration of lidocaine around the phrenic nerve would reduce tidal volume (VT) and peak transpulmonary pressure in spontaneously breathing patients with acute respiratory distress syndrome.
METHODS
An established animal model of acute respiratory distress syndrome with six female pigs was used in a proof-of-concept study. The authors then evaluated this technique in nine mechanically ventilated patients under pressure support exhibiting driving pressure greater than 15 cm H2O or VT greater than 10 ml/kg of predicted body weight. Esophageal and transpulmonary pressures, electrical activity of the diaphragm, and electrical impedance tomography were measured in pigs and patients. Ultrasound imaging and a nerve stimulator were used to identify the phrenic nerve, and perineural lidocaine was administered sequentially around the left and right phrenic nerves.
RESULTS
Results are presented as median [interquartile range, 25th to 75th percentiles]. In pigs, VT decreased from 7.4 ml/kg [7.2 to 8.4] to 5.9 ml/kg [5.5 to 6.6] (P < 0.001), as did peak transpulmonary pressure (25.8 cm H2O [20.2 to 27.2] to 17.7 cm H2O [13.8 to 18.8]; P < 0.001) and driving pressure (28.7 cm H2O [20.4 to 30.8] to 19.4 cm H2O [15.2 to 22.9]; P < 0.001). Ventilation in the most dependent part decreased from 29.3% [26.4 to 29.5] to 20.1% [15.3 to 20.8] (P < 0.001). In patients, VT decreased (8.2 ml/ kg [7.9 to 11.1] to 6.0 ml/ kg [5.7 to 6.7]; P < 0.001), as did driving pressure (24.7 cm H2O [20.4 to 34.5] to 18.4 cm H2O [16.8 to 20.7]; P < 0.001). Esophageal pressure, peak transpulmonary pressure, and electrical activity of the diaphragm also decreased. Dependent ventilation only slightly decreased from 11.5% [8.5 to 12.6] to 7.9% [5.3 to 8.6] (P = 0.005). Respiratory rate did not vary. Variables recovered 1 to 12.7 h [6.7 to 13.7] after phrenic nerve block.
CONCLUSIONS
Phrenic nerve block is feasible, lasts around 12 h, and reduces VT and driving pressure without changing respiratory rate in patients under assisted ventilation.
Topics: Acute Lung Injury; Animals; Critical Illness; Disease Models, Animal; Female; Humans; Lidocaine; Phrenic Nerve; Respiration, Artificial; Respiratory Distress Syndrome; Respiratory Mechanics; Swine; Tidal Volume
PubMed: 35348581
DOI: 10.1097/ALN.0000000000004161 -
Experimental Physiology Nov 2019What is the topic of this review? Rubral modulation of pontomedullary respiratory rhythm and pattern generating circuitry powerfully contributes to regulation of... (Review)
Review
NEW FINDINGS
What is the topic of this review? Rubral modulation of pontomedullary respiratory rhythm and pattern generating circuitry powerfully contributes to regulation of breathing. What advances does it highlight? Studies have demonstrated extensive rubromedullary and rubrospinal projections to zones generating and organizing the respiratory rhythm and pattern. Rubral modulation of respiratory output effects inspiratory expiratory phase transitions with stimulation generating inhibitory or excitatory responses of medullary inspiratory and expiratory units. The red nucleus mediates hypoxic ventilatory depression, integrates respiratory output with oromotor and locomotor activity, and modulates respiratory output during noxious stimulation.
ABSTRACT
Although normal triphasic eupnoea can be produced by the pontomedullary respiratory network after pontomesencephalic transection, the midbrain provides important modulation of respiration. Specifically, stimulation of the red nucleus elicits inspiratory inhibition, as manifest in the phrenic neurogram, in addition to excitation and inhibition of individual medullary respiratory-related units, with the majority of premotor units that receive rubral modulation being inhibited. Stimulation of the red nucleus also induces respiratory phase transitions, which appear to be pontine independent. These effects might be mediated by rubrobulbar and/or rubrospinal tracts. Although lesioning of the red nucleus does not alter respiration in normoxic conditions, it eliminates hypoxic ventilatory depression, which is the second phase of the biphasic ventilatory response to low oxygen tension. The finding that the red nucleus also plays a role in anti-nociception suggests that it might coordinate respiratory responses during noxious stimulation and, given that the red nucleus regulates upper limb flexors, it might represent one region in a distributed bulbar network contributing to respiratory-locomotor integration. Modulation of jaw opening by the red nucleus would support a model whereby it coordinates oromotor activity with breathing. Thus, the multiplicity of roles played by the red nucleus aptly position it to coordinate respiration in a variety of behavioural states. In this review, we seek to highlight the different features and regional specializations of the rubral contribution to respiratory control and underscore its vital importance to breathing in the freely behaving mammal.
Topics: Animals; Exhalation; Locomotion; Medulla Oblongata; Phrenic Nerve; Respiration; Respiratory Center
PubMed: 31408227
DOI: 10.1113/EP087720 -
American Journal of Respiratory and... May 2022
Topics: Diaphragm; Humans; Phrenic Nerve; Sleep Apnea, Central
PubMed: 35320061
DOI: 10.1164/rccm.202202-0315ED -
The Journal of Thoracic and... May 2021
Topics: Cardiac Surgical Procedures; Chest Tubes; Humans; Infant; Infant, Newborn; Paralysis; Phrenic Nerve
PubMed: 32711996
DOI: 10.1016/j.jtcvs.2020.06.048 -
Sleep Medicine Reviews Aug 2023Patients with central sleep apnea (CSA) have a lower quality of life and higher morbidity and mortality. Phrenic nerve stimulation (PNS) is a novel treatment for CSA... (Meta-Analysis)
Meta-Analysis Review
Patients with central sleep apnea (CSA) have a lower quality of life and higher morbidity and mortality. Phrenic nerve stimulation (PNS) is a novel treatment for CSA that has been shown to be safe. However, the effects of PNS on sleep changes are still under debate. This meta-analysis was performed to evaluate the efficacy of PNS in patients with CSA. PubMed, Scopus, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL) and Web of Science databases were searched for relevant studies published. We performed random-effects meta-analyses of the changes in apnea-hypopnea index (AHI), central apnea index (CAI), Arousal Index, percent of sleep with O2 saturation <90% (T90), Epworth Sleepiness Scale (ESS) and sleep efficiency. Ten studies with a total of 580 subjects were analyzed. Overall meta-analysis showed AHI [SMD: -2.24, 95% confidence interval (CI): was -3.11 to -1.36(p<0.00001)], CAI [SMD: -2.32, 95% CI: -3.17 to -1.47 (p<0.00001)] and Arousal Index (p = 0.0002, SMD (95% CI) -1.79 (-2.74 to -0.85)) significantly reduced after PNS. No significant changes were observed in T90, ESS and sleep efficiency (p > 0.05). Meta-analysis of observational studies demonstrated AHI, CAI and Arousal Index had a decreasing trend between before and after PNS (all, p<0.05). However, ESS and T90 did not change significantly after PNS (p > 0.05). Meta-analysis of RCTs showed that CSA patients had trends of a lower AHI (I = 0%), CAI (I = 74%), Arousal Index (I = 0%), T90 (I = 0%) and ESS (I = 0%) after PNS (all, p<0.05). The use of PNS appears to be safe and feasible in patients with CSA. However, larger, independent RCTs are required to investigate the efficacy and long-term effect of PNS and more attention should be paid to T90 and ESS.
Topics: Humans; Sleep Apnea, Central; Phrenic Nerve; Quality of Life; Polysomnography; Sleep
PubMed: 37467524
DOI: 10.1016/j.smrv.2023.101819