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Muscle & Nerve Mar 2021Unilateral diaphragmatic paralysis (UDP) has major clinical and etiological implications and, therefore, is important to diagnose. Lung function tests and invasive...
BACKGROUND
Unilateral diaphragmatic paralysis (UDP) has major clinical and etiological implications and, therefore, is important to diagnose. Lung function tests and invasive transdiaphragmatic pressure (Pdi) measurements are widely used to this end but, contrary to phrenic nerve conduction study (NCS), they require volitional maneuvers and/or may be poorly tolerated by patients. The purpose of this study was to compare the diagnostic accuracy of Pdi and phrenic NCS for UDP.
METHODS
We retrospectively reviewed 28 patients with suspected UDP. The diagnosis established during a multidisciplinary meeting was the reference standard.
RESULTS
Phrenic NCS correlated well with Pdi (r = 0.82, P < .005), and the two tests showed good agreement (κ = 0.82, P < .005). Phrenic NCS and Pdi measurements both had 95% sensitivity, 87.5% specificity, 95% positive predictive, and 87.5% negative predictive values.
CONCLUSIONS
Both tests were highly sensitive and specific. Phrenic NCS measurement is a simple, reproducible, noninvasive method whose results correlate well with Pdi and provide insight into the UDP mechanism. In the most difficult cases, combining lung function tests, respiratory muscle assessments, and phrenic NCS can help to establish the diagnosis.
Topics: Adult; Aged; Electrodiagnosis; Esophagus; Female; Humans; Male; Middle Aged; Neural Conduction; Phrenic Nerve; Predictive Value of Tests; Pressure; Respiratory Function Tests; Respiratory Muscles; Respiratory Paralysis; Retrospective Studies; Sensitivity and Specificity; Stomach; Transducers, Pressure
PubMed: 33314195
DOI: 10.1002/mus.27144 -
Neurology India 2022To report a new patient friendly and convenient technique for phrenic nerve conduction with alternative sites of stimulation and recording.
OBJECTIVE
To report a new patient friendly and convenient technique for phrenic nerve conduction with alternative sites of stimulation and recording.
METHODS
Phrenic nerve conduction was performed in forty volunteers and ten patients of peripheral neuropathy. Active recording electrode was placed in tenth intercostal space 2.5 cm away from para-spinal muscles (mid-scapular line), reference electrode in eighth intercostal space just medial to subcostal margin with ground between stimulating and recording electrode. Stimulation was done at the level of crico-thyroid space near or under the posterior margin of sternocleidomastoid muscle. This new method was compared with existing ones.
ANALYSIS
Data was analysed using SPSS 23 version. Correlation between height, weight, body mass index, age, and chest expansion was done using bi-variate correlation. Mean latency and amplitude of the study method were compared with other methods using MANNOVA test.
RESULTS
Total of forty subjects were studied. Thirty-seven were male subjects. Mean age was 28.03 ± 9.63 years, height 168.0 ± 9.60 cm and chest expansion 3.53 ± 0.64 cm. Right sided phrenic nerve mean latency was 5.99 ± 0.629 ms and amplitude 1.088 ± 0.178 mV. Left sided phrenic nerve conductions showed mean latency of 6.02 ± 1.82 ms, amplitude of 1.092 ± 0.2912 mV. These standard deviations were smaller than what were observed with other methods suggesting increased consistency of our results. There was no correlation between phrenic nerve conduction with age, height, gender or chest expansion.
CONCLUSION
This study method gave a better as well as consistent morphology, higher amplitude and required lower amount of current strength. It was superior to previously reported methods in consistency of normative data.
Topics: Adolescent; Adult; Female; Humans; Male; Young Adult; Action Potentials; Back; Electrodes; Electromyography; Neck; Neural Conduction; Neurologic Examination; Peripheral Nervous System Diseases; Phrenic Nerve
PubMed: 36412357
DOI: 10.4103/0028-3886.360904 -
Revue Medicale Suisse Sep 2020Diaphragmatic paresis/paralysis can be unilateral or bilateral. Its manifestations range from completely asymptomatically to global respiratory failure. Respiratory... (Review)
Review
Diaphragmatic paresis/paralysis can be unilateral or bilateral. Its manifestations range from completely asymptomatically to global respiratory failure. Respiratory functional tests will reveal lowered respiratory pressures with a restrictive syndrome, and a decrease in vital capacity when lying in the supine position compared to sitting. Unilateral paresis is most often self-limited and mainly post-surgical. The bilateral dysfunction, observed in neuromuscular diseases, is often permanent. The treatment consists in the management of specific causes, the optimization of the treatment of comorbidities, and in some cases, diaphragmatic plication, ventilatory support or pacing of phrenic nerves.
Topics: Diaphragm; Humans; Paresis; Phrenic Nerve; Respiratory Insufficiency; Respiratory Paralysis
PubMed: 32914596
DOI: No ID Found -
Interactive Cardiovascular and Thoracic... May 2021Bilateral diaphragmatic dysfunction results in severe dyspnoea, usually requiring oxygen therapy and nocturnal ventilatory support. Although treatment options are...
OBJECTIVES
Bilateral diaphragmatic dysfunction results in severe dyspnoea, usually requiring oxygen therapy and nocturnal ventilatory support. Although treatment options are limited, phrenic nerve reconstruction (PR) offers the opportunity to restore functional activity. This study aims to evaluate combination treatment with PR and placement of a diaphragm pacemaker (DP) compared to DP placement alone in patients with bilateral diaphragmatic dysfunction.
METHODS
Patients with bilateral diaphragmatic dysfunction were prospectively enrolled in the following treatment algorithm: Unilateral PR was performed on the more severely impacted side with bilateral DP implantation. Motor amplitudes, ultrasound measurements of diaphragm thickness, maximal inspiratory pressure, forced expiratory volume, forced vital capacity and subjective patient-reported outcomes were obtained for retrospective analysis following completion of the prospective database.
RESULTS
Fourteen male patients with bilateral diaphragmatic dysfunction confirmed on chest fluoroscopy and electrodiagnostic testing were included. All 14 patients required nocturnal ventilator support, and 8/14 (57.1%) were oxygen-dependent. All patients reported subjective improvement, and all 8 oxygen-dependent patients were able to discontinue oxygen therapy following treatment. Improvements in maximal inspiratory pressure, forced vital capacity and forced expiratory volume were 68%, 47% and 53%, respectively. There was an average improvement of 180% in motor amplitude and a 50% increase in muscle thickness. Comparison of motor amplitude changes revealed significantly greater functional recovery on the PR + DP side.
CONCLUSIONS
PR and simultaneous implantation of a DP may restore functional activity and alleviate symptoms in patients with bilateral diaphragmatic dysfunction. PR plus diaphragm pacing appear to result in greater functional muscle recovery than pacing alone.
Topics: Diaphragm; Humans; Male; Phrenic Nerve; Respiratory Paralysis; Retrospective Studies
PubMed: 33432336
DOI: 10.1093/icvts/ivaa324 -
Journal of the Peripheral Nervous... Sep 2019Diaphragm weakness in Charcot-Marie-Tooth disease 1A (CMT1A) is usually associated with severe disease manifestation. This study comprehensively investigated phrenic...
Diaphragm weakness in Charcot-Marie-Tooth disease 1A (CMT1A) is usually associated with severe disease manifestation. This study comprehensively investigated phrenic nerve conductivity, inspiratory and expiratory muscle function in ambulatory CMT1A patients. Nineteen adults with CMT1A (13 females, 47 ± 12 years) underwent spiromanometry, diaphragm ultrasound, and magnetic stimulation of the phrenic nerves and the lower thoracic nerve roots, with recording of diaphragm compound muscle action potentials (dCMAP, n = 15), transdiaphragmatic and gastric pressures (twPdi and twPgas, n = 12). Diaphragm motor evoked potentials (dMEP, n = 15) were recorded following cortical magnetic stimulation. Patients had not been selected for respiratory complaints. Disease severity was assessed using the CMT Neuropathy Scale version 2 (CMT-NSv2). Healthy control subjects were matched for age, sex, and body mass index. The following parameters were significantly lower in CMT1A patients than in controls (all P < .05): forced vital capacity (91 ± 16 vs 110 ± 15% predicted), maximum inspiratory pressure (68 ± 22 vs 88 ± 29 cmH O), maximum expiratory pressure (91 ± 23 vs 123 ± 24 cmH O), and peak cough flow (377 ± 135 vs 492 ± 130 L/min). In CMT1A patients, dMEP and dCMAP were delayed. Patients vs controls showed lower diaphragm excursion (5 ± 2 vs 8 ± 2 cm), diaphragm thickening ratio (DTR, 1.9 [1.6-2.2] vs 2.5 [2.1-3.1]), and twPdi (8 ± 6 vs 19 ± 7 cmH O; all P < .05). DTR inversely correlated with the CMT-NSv2 score (r = -.59, P = .02). There was no group difference in twPgas following abdominal muscle stimulation. Ambulatory CMT1A patients may show phrenic nerve involvement and reduced respiratory muscle strength. Respiratory muscle weakness can be attributed to diaphragm dysfunction alone. It relates to neurological impairment and likely reflects a disease continuum.
Topics: Adult; Charcot-Marie-Tooth Disease; Diaphragm; Electric Stimulation; Female; Humans; Male; Middle Aged; Muscle Weakness; Phrenic Nerve; Respiratory Muscles; Ultrasonography
PubMed: 31393643
DOI: 10.1111/jns.12341 -
Journal of Hand and Microsurgery Jun 2024Brachial plexus injuries are debilitating injuries resulting in paralyzed shoulder to global paralysis of the upper extremity. Treatment strategies have evolved over the...
BACKGROUND
Brachial plexus injuries are debilitating injuries resulting in paralyzed shoulder to global paralysis of the upper extremity. Treatment strategies have evolved over the years with nerve transfer forming the mainstay of surgical management. Phrenic nerve provides certain advantages as donor over other options but has been less preferred due to fear of pulmonary complications. In this study, we assess the functional outcomes of phrenic nerve transfer in brachial plexus injuries.
MATERIALS AND METHODS
A retrospective study was performed on 18 patients operated between 2012 and 2017. The mean duration of injury to surgery was 4.56 months and mean follow-up was for 3.66 years. Phrenic nerve was used as donor to neurotize either biceps and brachialis branch of musculocutaneous nerve or suprascapular nerve. Assessment was done through Waikakul score for elbow flexion and Medical Research Council grading for shoulder abduction. Respiratory function assessment was done through questionnaire.
RESULTS
Twelve (80%) patients recovered grade 3 and above elbow flexion with 6 patients having a positive endurance test according to Waikakul and a "very good" result. In phrenic to suprascapular transfer group (3 patients), all patients had more than grade 3 recovery of shoulder abduction. No patient complained of respiratory problems.
CONCLUSION
Phrenic nerve can be used as a reliable donor with suitable patient selection with good results in regaining muscle power without any anticipated effects on respiratory function.
PubMed: 38855508
DOI: 10.1055/s-0043-1764162 -
The American Journal of Cardiology Oct 2022RespiCardia remedē System (Minnetonka, MN 2017), a transvenous phrenic nerve stimulator, is indicated to treat central sleep apnea (CSA) by stimulating the phrenic...
RespiCardia remedē System (Minnetonka, MN 2017), a transvenous phrenic nerve stimulator, is indicated to treat central sleep apnea (CSA) by stimulating the phrenic nerve to cause diaphragmatic contraction to restore normal breathing during sleep. CSA is associated with decreased patient quality of life and worsens cardiovascular outcomes. Systematic review was conducted according to the Preferred Reporting of Systematic Reviews and Meta-Analysis guidelines. PubMed/MEDLINE, Cochrane, EBSCO CINAHL, and Ovid databases were queried by 2 independent reviewers for English-language studies published between 2000 and 2021. The initial search screened for all occurrences of "remedē" then was further refined to include studies evaluating use of the RespiCardia remedē System as a treatment for CSA in multiple patients. A total of 124 articles were identified from the initial search results. A total of 37 articles were identified through screening of title and abstracts from initial results. Full-text review of all the articles was then completed. Of the 13 articles included, a total of 232 patients underwent device implantation. We sought to summarize the available evidence regarding patient selection for implantation, immediate and delayed complications, adherence to therapy, and polysomnographic evidence of efficacy. All 13 articles detailed significant decreases in central apnea index and many patients reported significant mild to marked improvement in quality of life. In conclusion, the remedē System has been demonstrated to improve sleep and respiratory parameters, with few complications. This device demonstrates safe and effective treatment of moderate to severe CSA in adult patients, including those with heart failure.
Topics: Adult; Electric Stimulation Therapy; Humans; Phrenic Nerve; Quality of Life; Sleep Apnea, Central; Systematic Reviews as Topic
PubMed: 35918232
DOI: 10.1016/j.amjcard.2022.06.038 -
Journal of Thoracic Disease Aug 2022The objective of this study was to assess the feasibility and safety of a novel, removable, surgically implanted, temporary neurostimulation approach involving the...
BACKGROUND
The objective of this study was to assess the feasibility and safety of a novel, removable, surgically implanted, temporary neurostimulation approach involving the distal portion of the phrenic nerve.
METHODS
Temporary phrenic nerve pacing electrodes were implanted surgically using an ovine model (4 animals). The primary endpoint was the ability to successfully match the animal's minute-ventilation upon implantation of both phrenic nerve pacers on day 1. Secondary endpoints were successful phrenic neurostimulation by both electrodes 15 and 30 days after initial implantation. We also assessed safe removal of the electrodes at 15 and 30 days after implementation.
RESULTS
In 3 of 4 animals, electrodes were successfully implanted in both right and left phrenic nerves. On day 1, median ventilation-minute induced by neurostimulation was not significantly different from baseline ventilation-minute [4.9 L·min (4.4-5.5) 4.4 L·min (4.3-5.2); P=0.4] after 15 minutes. Neurostimulation was still possible 15 and 30 days after implementation in all left side phrenic nerves. On the right side, stimulation was possible at all times in 1 animal but not in the remaining 3 animals for at least one time point, possibly due to lead displacement. Analysis of pathology after percutaneous electrode removal showed integrity of the distal portion of all phrenic nerves.
CONCLUSIONS
Efficient temporary neurostimulation through the distal portion of the phrenic nerve was possible at baseline. The main complication was the displacement of electrodes on the right phrenic nerve on two occasions, which was due to the anatomy of the ovine model. It compromised diaphragm pacing on day 15 and day 30. The electrodes could be safely removed percutaneously without damage to the phrenic nerves.
PubMed: 36071760
DOI: 10.21037/jtd-21-1944 -
Artificial Organs Mar 2023Prolonged mechanical ventilation caused by ventilator-induced diaphragm dysfunction (VIDD) is a serious problem in critically ill patients. Identification of patients... (Review)
Review
BACKGROUND
Prolonged mechanical ventilation caused by ventilator-induced diaphragm dysfunction (VIDD) is a serious problem in critically ill patients. Identification of patients who will have difficulty weaning from ventilation along with attempts to reduce total time on mechanical ventilation is some of the aims of intensive care medicine.
OBSERVATIONS
This article briefly summarizes current options for temporary phrenic nerve stimulation therapy in an effort to keep the diaphragm active as direct prevention and treatment of ventilator-associated diaphragmatic dysfunction in patients on mechanical ventilation. The results of feasibility studies using different approaches are promising but so far, the clinical relevance is low. One important question is which tool would reliably identify early signs of diaphragmatic dysfunction and also be useful in guiding therapy. The authors present a brief overview of the current options considering the advantages and disadvantages of the available examination modalities. Despite the fact that current data point out some limitations of ultrasound examination, we believe that it still has a unique position in the bedside examination of critically ill patients on mechanical ventilation.
CONCLUSION
Temporary phrenic nerve stimulation, regardless of the specific approach used, has the potential to directly treat or reverse VIDD, and ultrasound examination plays an important role in the comprehensive care of critically ill patients.
Topics: Humans; Phrenic Nerve; Critical Illness; Respiration, Artificial; Ventilators, Mechanical; Respiration
PubMed: 36398921
DOI: 10.1111/aor.14453 -
Artificial Organs Oct 2022Diaphragm muscle atrophy during mechanical ventilation begins within 24 h and progresses rapidly with significant clinical consequences. Electrical stimulation of the...
BACKGROUND
Diaphragm muscle atrophy during mechanical ventilation begins within 24 h and progresses rapidly with significant clinical consequences. Electrical stimulation of the phrenic nerves using invasive electrodes has shown promise in maintaining diaphragm condition by inducing intermittent diaphragm muscle contraction. However, the widespread application of these methods may be limited by their risks as well as the technical and environmental requirements of placement and care. Non-invasive stimulation would offer a valuable alternative method to maintain diaphragm health while overcoming these limitations.
METHODS
We applied non-invasive electrical stimulation to the phrenic nerve in the neck in healthy volunteers. Respiratory pressure and flow, diaphragm electromyography and mechanomyography, and ultrasound visualization were used to assess the diaphragmatic response to stimulation. The electrode positions and stimulation parameters were systematically varied in order to investigate the influence of these parameters on the ability to induce diaphragm contraction with non-invasive stimulation.
RESULTS
We demonstrate that non-invasive capture of the phrenic nerve is feasible using surface electrodes without the application of pressure, and characterize the stimulation parameters required to achieve therapeutic diaphragm contractions in healthy volunteers. We show that an optimal electrode position for phrenic nerve capture can be identified and that this position does not vary as head orientation is changed. The stimulation parameters required to produce a diaphragm response at this site are characterized and we show that burst stimulation above the activation threshold reliably produces diaphragm contractions sufficient to drive an inspired volume of over 600 ml, indicating the ability to produce significant diaphragmatic work using non-invasive stimulation.
CONCLUSION
This opens the possibility of non-invasive systems, requiring minimal specialist skills to set up, for maintaining diaphragm function in the intensive care setting.
Topics: Critical Care; Diaphragm; Electric Stimulation; Humans; Phrenic Nerve; Respiration, Artificial; Ventilators, Mechanical
PubMed: 35377472
DOI: 10.1111/aor.14244