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Pulmonology 2019The diaphragm is the main breathing muscle and contraction of the diaphragm is vital for ventilation so any disease that interferes with diaphragmatic innervation,... (Comparative Study)
Comparative Study Review
The diaphragm is the main breathing muscle and contraction of the diaphragm is vital for ventilation so any disease that interferes with diaphragmatic innervation, contractile muscle function, or mechanical coupling to the chest wall can cause diaphragm dysfunction. Diaphragm dysfunction is associated with dyspnoea, intolerance to exercise, sleep disturbances, hypersomnia, with a potential impact on survival. Diagnosis of diaphragm dysfunction is based on static and dynamic imaging tests (especially ultrasound) and pulmonary function and phrenic nerve stimulation tests. Treatment will depend on the symptoms and causes of the disease. The management of diaphragm dysfunction may include observation in asymptomatic patients with unilateral dysfunction, surgery (i.e., plication of the diaphragm), placement of a diaphragmatic pacemaker or invasive and/or non-invasive mechanical ventilation in symptomatic patients with bilateral paralysis of the diaphragm. This type of patient should be treated in experienced centres. This review aims to provide an overview of the problem, with special emphasis on the diseases that cause diaphragmatic dysfunction and the diagnostic and therapeutic procedures most commonly employed in clinical practice. The ultimate goal is to establish a standard of care for diaphragmatic dysfunction.
Topics: Diaphragm; Diaphragmatic Eventration; Fluoroscopy; Humans; Microsurgery; Phrenic Nerve; Radiography; Respiration, Artificial; Respiratory Function Tests; Respiratory Paralysis; Transcutaneous Electric Nerve Stimulation; Ultrasonography
PubMed: 30509855
DOI: 10.1016/j.pulmoe.2018.10.008 -
Journal of Neurophysiology Dec 2017Large-diameter myelinated phrenic afferents discharge in phase with diaphragm contraction, and smaller diameter fibers discharge across the respiratory cycle. In this... (Review)
Review
Large-diameter myelinated phrenic afferents discharge in phase with diaphragm contraction, and smaller diameter fibers discharge across the respiratory cycle. In this article, we review the phrenic afferent literature and highlight areas in need of further study. We conclude that ) activation of both myelinated and nonmyelinated phrenic sensory afferents can influence respiratory motor output on a breath-by-breath basis; ) the relative impact of phrenic afferents substantially increases with diaphragm work and fatigue; ) activation of phrenic afferents has a powerful impact on sympathetic motor outflow, and ) phrenic afferents contribute to diaphragm somatosensation and the conscious perception of breathing. Much remains to be learned regarding the spinal and supraspinal distribution and synaptic contacts of myelinated and nonmyelinated phrenic afferents. Similarly, very little is known regarding the potential role of phrenic afferent neurons in triggering or modulating expression of respiratory neuroplasticity.
Topics: Animals; Diaphragm; Humans; Neuronal Plasticity; Neurons, Afferent; Nociception; Phrenic Nerve; Respiration
PubMed: 28835527
DOI: 10.1152/jn.00484.2017 -
Anesthesiology Jul 2017Regional anesthesia has an established role in providing perioperative analgesia for shoulder surgery. However, phrenic nerve palsy is a significant complication that... (Review)
Review
Regional anesthesia has an established role in providing perioperative analgesia for shoulder surgery. However, phrenic nerve palsy is a significant complication that potentially limits the use of regional anesthesia, particularly in high-risk patients. The authors describe the anatomical, physiologic, and clinical principles relevant to phrenic nerve palsy in this context. They also present a comprehensive review of the strategies for reducing phrenic nerve palsy and its clinical impact while ensuring adequate analgesia for shoulder surgery. The most important of these include limiting local anesthetic dose and injection volume and performing the injection further away from the C5-C6 nerve roots. Targeting peripheral nerves supplying the shoulder, such as the suprascapular and axillary nerves, may be an effective alternative to brachial plexus blockade in selected patients. The optimal regional anesthetic approach in shoulder surgery should be tailored to individual patients based on comorbidities, type of surgery, and the principles described in this article.
Topics: Anesthesia, Conduction; Humans; Paralysis; Phrenic Nerve; Shoulder
PubMed: 28514241
DOI: 10.1097/ALN.0000000000001668 -
American Journal of Respiratory and... May 2022
Topics: Diaphragm; Humans; Phrenic Nerve; Sleep Apnea, Central
PubMed: 35320061
DOI: 10.1164/rccm.202202-0315ED -
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 -
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 -
Biomedical Engineering Online Jan 2023Every year, more than 2.5 million critically ill patients in the ICU are dependent on mechanical ventilation. The positive pressure in the lungs generated by the...
BACKGROUND
Every year, more than 2.5 million critically ill patients in the ICU are dependent on mechanical ventilation. The positive pressure in the lungs generated by the ventilator keeps the diaphragm passive, which can lead to a loss of myofibers within a short time. To prevent ventilator-induced diaphragmatic dysfunction (VIDD), phrenic nerve stimulation may be used.
OBJECTIVE
The goal of this study is to show the feasibility of transesophageal phrenic nerve stimulation (TEPNS). We hypothesize that selective phrenic nerve stimulation can efficiently activate the diaphragm with reduced co-stimulations.
METHODS
An in vitro study in saline solution combined with anatomical findings was performed to investigate relevant stimulation parameters such as inter-electrode spacing, range to target site, or omnidirectional vs. sectioned electrodes. Subsequently, dedicated esophageal electrodes were inserted into a pig and single stimulation pulses were delivered simultaneously with mechanical ventilation. Various stimulation sites and response parameters such as transdiaphragmatic pressure or airway flow were analyzed to establish an appropriate stimulation setting.
RESULTS
Phrenic nerve stimulation with esophageal electrodes has been demonstrated. With a current amplitude of 40 mA, similar response figures of the diaphragm activation as compared to conventional stimulation with needle electrodes at 10mA were observed. Directed electrodes best aligned with the phrenic nerve resulted in up to 16.9 % higher amplitude at the target site in vitro and up to 6 cmH20 higher transdiaphragmatic pressure in vivo as compared to omnidirectional electrodes. The activation efficiency was more sensitive to the stimulation level inside the esophagus than to the inter-electrode spacing. Most effective and selective stimulation was achieved at the level of rib 1 using sectioned electrodes 40 mm apart.
CONCLUSION
Directed transesophageal phrenic nerve stimulation with single stimuli enabled diaphragm activation. In the future, this method might keep the diaphragm active during, and even support, artificial ventilation. Meanwhile, dedicated sectioned electrodes could be integrated into gastric feeding tubes.
Topics: Animals; Swine; Phrenic Nerve; Feasibility Studies; Diaphragm; Respiration, Artificial; Electrodes; Electric Stimulation
PubMed: 36717872
DOI: 10.1186/s12938-023-01071-5 -
Circulation. Arrhythmia and... Jun 2022Phrenic nerve palsy is a well-known complication of cardiac ablation, resulting from the application of direct thermal energy. Emerging pulsed field ablation (PFA) may...
BACKGROUND
Phrenic nerve palsy is a well-known complication of cardiac ablation, resulting from the application of direct thermal energy. Emerging pulsed field ablation (PFA) may reduce the risk of phrenic nerve injury but has not been well characterized.
METHODS
Accelerometers and continuous pacing were used during PFA deliveries in a porcine model. Acute dose response was established in a first experimental phase with ascending PFA intensity delivered to the phrenic nerve (n=12). In a second phase, nerves were targeted with a single ablation level to observe the effect of repetitive ablations on nerve function (n=4). A third chronic phase characterized assessed histopathology of nerves adjacent to ablated cardiac tissue (n=6).
RESULTS
Acutely, we observed a dose-dependent response in phrenic nerve function including reversible stunning (R=0.965, <0.001). Furthermore, acute results demonstrated that phrenic nerve function responded to varying levels of PFA and catheter proximity placements, resulting in either: no effect, effect, or stunning. In the chronic study phase, successful isolation of superior vena cava at a dose not predicted to cause phrenic nerve dysfunction was associated with normal phrenic nerve function and normal phrenic nerve histopathology at 4 weeks.
CONCLUSIONS
Proximity of the catheter to the phrenic nerve and the PFA dose level were critical for phrenic nerve response. Gross and histopathologic evaluation of phrenic nerves and diaphragms at a chronic time point yielded no injury. These results provide a basis for understanding the susceptibility and recovery of phrenic nerves in response to PFA and a need for appropriate caution in moving beyond animal models.
Topics: Animals; Atrial Fibrillation; Catheter Ablation; Peripheral Nerve Injuries; Phrenic Nerve; Pulmonary Veins; Swine; Vena Cava, Superior
PubMed: 35649121
DOI: 10.1161/CIRCEP.121.010127 -
Europace : European Pacing,... Apr 2023
Topics: Humans; Atrial Fibrillation; Phrenic Nerve; Echocardiography; Pericardium
PubMed: 37061851
DOI: 10.1093/europace/euad054 -
Arquivos de Neuro-psiquiatria Dec 2017The aim of the present study was to define normative data of phrenic nerve conduction parameters of a healthy population.
OBJECTIVE
The aim of the present study was to define normative data of phrenic nerve conduction parameters of a healthy population.
METHODS
Phrenic nerve conduction studies were performed in 27 healthy volunteers.
RESULTS
The normative limits for expiratory phrenic nerve compound muscle action potential were: amplitude (0.47 mv - 0.83 mv), latency (5.74 ms - 7.10 ms), area (6.20 ms/mv - 7.20 ms/mv) and duration (18.30 ms - 20.96 ms). Inspiratory normative limits were: amplitude (0.67 mv - 1.11 mv), latency (5.90 ms - 6.34 ms), area (5.62 ms/mv - 6.72 ms/mv) and duration (13.77 ms - 15.37 ms).
CONCLUSION
The best point of phrenic nerve stimulus in the neck varies among individuals between the medial and lateral border of the clavicular head of the sternocleidomastoid muscle and stimulation of both sites, then choosing the best phrenic nerve response, seems to be the appropriate procedure.
Topics: Action Potentials; Adult; Electric Stimulation; Electromyography; Female; Healthy Volunteers; Humans; Male; Middle Aged; Neural Conduction; Neurologic Examination; Phrenic Nerve; Reaction Time; Young Adult
PubMed: 29236890
DOI: 10.1590/0004-282X20170153