scholarly journals Comparison of magnetic and electrical phrenic nerve stimulation in assessment of phrenic nerve conduction time

1997 ◽  
Vol 82 (4) ◽  
pp. 1190-1199 ◽  
Author(s):  
Thomas Similowski ◽  
Selma Mehiri ◽  
Alexandre Duguet ◽  
Valérie Attali ◽  
Christian Straus ◽  
...  
Keyword(s):  
Nerve Stimulation ◽  
Phrenic Nerve ◽  
Nerve Conduction ◽  
Clinical Implications ◽  
Conduction Time ◽  
Electromyographic Activity ◽  
Average Difference ◽  
Phrenic Nerve Stimulation ◽  
Stimulation Of

Similowski, Thomas, Selma Mehiri, Alexandre Duguet, Valérie Attali, Christian Straus, and Jean-Philippe Derenne.Comparison of magnetic and electrical phrenic nerve stimulation in assessment of phrenic nerve conduction time. J. Appl. Physiol. 82(4): 1190–1199, 1997.—Cervical magnetic stimulation (CMS), a nonvolitional test of diaphragm function, is an easy means for measuring the latency of the diaphragm motor response to phrenic nerve stimulation, namely, phrenic nerve conduction time (PNCT). In this application, CMS has some practical advantages over electrical stimulation of the phrenic nerve in the neck (ES). Although normal ES-PNCTs have been consistently reported between 7 and 8 ms, data are less homogeneous for CMS-PNCTs, with some reports suggesting lower values. This study systematically compares ES- and CMS-PNCTs for the same subjects. Surface recordings of diaphragmatic electromyographic activity were obtained for seven healthy volunteers during ES and CMS of varying intensities. On average, ES-PNCTs amounted to 6.41 ± 0.84 ms and were little influenced by stimulation intensity. With CMS, PNCTs were significantly lower (average difference 1.05 ms), showing a marked increase as CMS intensity lessened. ES and CMS values became comparable for a CMS intensity 65% of the maximal possible intensity of 2.5 Tesla. These findings may be the result of phrenic nerve depolarization occurring more distally than expected with CMS, which may have clinical implications regarding the diagnosis and follow-up of phrenic nerve lesions.

Validation of improved recording site to measure phrenic conduction from surface electrodes in humans

2002 ◽  
Vol 92 (3) ◽  
pp. 967-974 ◽  
Author(s):  
Eric Verin ◽  
Christian Straus ◽  
Alexandre Demoule ◽  
Philippe Mialon ◽  
Jean-Philippe Derenne ◽  
...  
Keyword(s):  
Nerve Stimulation ◽  
Phrenic Nerve ◽  
Magnetic Stimulation ◽  
Conduction Time ◽  
Phrenic Nerve Stimulation ◽  
Recording Site ◽  
Serratus Anterior ◽  
Surface Electrodes ◽  
Phrenic Nerves

Phrenic nerve stimulation, electrical (ES) or from cervical magnetic stimulation (CMS), allows one to assess the diaphragm contractile properties and the conduction time of the phrenic nerve (PNCT) through recording of an electromyographic response, traditionally by using surface electrodes. Because of the coactivation of extradiaphragmatic muscles, signal contamination can jeopardize the determination of surface PNCTs. To address this, we compared PNCTs with ES and CMS from surface and needle diaphragm electrodes in five subjects (10 phrenic nerves). At a modified recording site, lower and more anterior than usual (lowest accessible intercostal space, costochondral junction) with electrodes 2 cm apart, surface and needle PNCTs were similar (CMS: 6.0 ± 0.25 ms surface vs. 6.2 ± 0.13 ms needle, not significant). Electrodes recording the activity of the most likely sources of signal contamination, i.e., the serratus anterior and pectoralis major, showed distinct responses from that of the diaphragm, their earlier occurrence strongly arguing against contamination. With ES and CMS, apparently uncontaminated signals could be consistently recorded from surface electrodes.

Determinants of diaphragm motion in unilateral diaphragmatic paralysis

2004 ◽  
Vol 96 (1) ◽  
pp. 96-100 ◽  
Author(s):  
Pierre Scillia ◽  
Matteo Cappello ◽  
André De Troyer
Keyword(s):  
Clinical Practice ◽  
Muscle Contraction ◽  
Nerve Stimulation ◽  
Phrenic Nerve ◽  
Diaphragmatic Paralysis ◽  
Phrenic Nerve Stimulation ◽  
Anesthetized Dogs ◽  
Diaphragm Motion ◽  
Cardinal Sign ◽  
Stimulation Of

Cranial displacement of a hemidiaphragm during sniffs is a cardinal sign of unilateral diaphragmatic paralysis in clinical practice. However, we have recently observed that isolated stimulation of one phrenic nerve in dogs causes the contralateral (inactive) hemidiaphragm to move caudally. In the present study, therefore, we tested the idea that, in unilateral diaphragmatic paralysis, the pattern of inspiratory muscle contraction plays a major role in determining the motion of the inactive hemidiaphragm. We induced a hemidiaphragmatic paralysis in six anesthetized dogs and assessed the contour of the diaphragm during isolated unilateral phrenic nerve stimulation and during spontaneous inspiratory efforts. Whereas the inactive hemidiaphragm moved caudally in the first instance, it moved cranially in the second. The parasternal intercostal muscles were then severed to reduce the contribution of the rib cage muscles to inspiratory efforts and to enhance the force generated by the intact hemidiaphragm. Although the change in pleural pressure (ΔPpl) was unaltered, the cranial displacement of the paralyzed hemidiaphragm was consistently reduced. A pneumothorax was finally induced to eliminate ΔPpl during unilateral phrenic nerve stimulation, and this enhanced the caudal displacement of the inactive hemidiaphragm. These observations indicate that, in unilateral diaphragmatic paralysis, the motion of the inactive hemidiaphragm is largely determined by the balance between the force related to ΔPpl and the force generated by the intact hemidiaphragm.

Electrophysiological evaluation of phrenic nerve function in candidates for diaphragm pacing

1980 ◽  
Vol 53 (3) ◽  
pp. 345-354 ◽  
Author(s):  
Richard K. Shaw ◽  
William W. L. Glenn ◽  
James F. Hogan ◽  
Mildred L. Phelps
Keyword(s):  
Action Potential ◽  
Nerve Injury ◽  
Nerve Stimulation ◽  
Phrenic Nerve ◽  
Conduction Time ◽  
Nerve Function ◽  
Muscle Action ◽  
Phrenic Nerve Stimulation ◽  
Diaphragm Pacing ◽  
Muscle Action Potential

✓ The electrophysiological status of phrenic nerve function has been determined by an assessment of the conduction time and diaphragm muscle action potential in patients who were being evaluated as candidates for diaphragm pacing, or who were being studied for suspected phrenic nerve injury or disease. The conduction time and muscle action potential were evoked by transcutaneous phrenic nerve stimulation or by stimulation with a permanently implanted diaphragm pacemaker. In normal volunteers, the conduction time was found to be 8.40 msec ± 0.78 msec (SD). Transcutaneous phrenic nerve stimulation was successful in predicting phrenic nerve viability in 116 of 120 nerves studied. The four false negatives were due to technical difficulty in locating the nerves in obese or uncooperative subjects. In patients who were selected for implantation of a diaphragm pacemaker, a conduction time that was prolonged (10 to 14 msec) preoperatively did not preclude successful diaphragm pacing. Postoperatively, a prolonged (> 10 msec) conduction time was associated with severe systemic disease or local nerve injury caused by trauma or infection. The elucidation of phrenic nerve function by such electrophysiological studies serves as a valuable adjunct to the selection and management of patients undergoing diaphragm pacing.

scholarly journals Phrenic Nerve Stimulation Improves Physical Performance and Hypoxemia in Heart Failure Patients with Central Sleep Apnea

2021 ◽  
Vol 10 (2) ◽  
pp. 202
Author(s):  
Max Potratz ◽  
Christian Sohns ◽  
Daniel Dumitrescu ◽  
Philipp Sommer ◽  
Henrik Fox
Keyword(s):  
Heart Failure ◽  
Sleep Apnea ◽  
Physical Performance ◽  
Nerve Stimulation ◽  
Phrenic Nerve ◽  
Central Sleep Apnea ◽  
Phrenic Nerve Stimulation ◽  
Performance Capacity ◽  
Physical Performance Capacity

Background: Central sleep apnea (CSA) is a common comorbidity in patients with heart failure (HF) and has been linked to increased morbidity and mortality risk. In addition, CSA is associated with impaired quality of life, reduced physical performance capacity, and hypoxemia. Phrenic nerve stimulation (PNS) is a novel approach to the treatment of CSA and has been shown to be safe and effective in this indication. However, there are currently no data on the effects of PNS on physical performance and hypoxia in CSA HF patients, both of which have been shown to be linked to mortality in HF. Methods: This prospective study enrolled patients with HF and CSA diagnosed using polysomnography. All were implanted with a PNS system (remedē® system, Respicardia Inc., Minnetonka, MN, USA) for the treatment of CSA. Examinations included polysomnography (to determine hypoxemic burden), echocardiography and a standardized 6-min walk test prior to device implantation (baseline) and after 6 months of follow-up. Results: A total of 24 patients were enrolled (mean age 67.1 ± 11.2 years, 88% male). The 6-min walk distance was 369.5 ± 163.5 m at baseline and significantly improved during follow-up (to 410 ± 169.7 m; p = 0.035). Hypoxemic burden, determined based on time with oxygen saturation < 90% improved from 81 ± 55.8 min at baseline to 27.9 ± 42.8 min during PNS therapy (p < 0.01). Conclusion: In addition to safely and effectively treating CSA, PNS is also associated with improved physical performance capacity and reduced hypoxemic burden in patients with HF.

Botzinger complex region role in phrenic-to-phrenic inhibitory reflex of cat

1989 ◽  
Vol 67 (4) ◽  
pp. 1364-1370 ◽  
Author(s):  
D. F. Speck
Keyword(s):  
Nerve Stimulation ◽  
Phrenic Nerve ◽  
Inhibitory Response ◽  
Phrenic Nerve Stimulation ◽  
Bötzinger Complex ◽  
Before And After ◽  
Pass Through ◽  
Bilateral Lesions ◽  
Decerebrate Cats ◽  
Inhibitory Reflex

Neuronal recordings, microstimulation, and electrolytic and chemical lesions were used to examine the involvement of the Botzinger Complex (BotC) in the bilateral phrenic-to-phrenic inhibitory reflex. Experiments were conducted in decerebrate cats that were paralyzed, ventilated, thoracotomized, and vagotomized. Microelectrode recordings within the BotC region revealed that some neurons were activated by phrenic nerve stimulation (15 of 69 expiratory units, 9 of 67 inspiratory units, and 19 nonrespiratory-modulated units) at average latencies similar to the onset latency of the phrenic-to-phrenic inhibition. In addition, microstimulation within the BotC caused a short latency transient inhibition of phrenic motor activity. In 17 cats phrenic neurogram responses to threshold and supramaximal (15 mA) stimulation of phrenic nerve afferents were recorded before and after electrolytic BotC lesions. In 15 animals the inhibitory reflex was attenuated by bilateral lesions. Because lesion of either BotC neurons or axons of passage could account for this attenuation, in eight experiments the phrenic-to-phrenic inhibitory responses were recorded before and after bilateral injections of 5 microM kainic acid (30–150 nl) into the BotC. After chemical lesions, the inhibitory response to phrenic nerve stimulation remained; however, neuronal activity typical of the BotC could not be located. These results suggest that axons important in producing the phrenic-to-phrenic reflex pass through the region of the BotC, but that BotC neurons themselves are not necessary for this reflex.

Mapping for Acute Transvenous Phrenic Nerve Stimulation Study (MAPS Study)

2017 ◽  
Vol 40 (3) ◽  
pp. 294-300
Author(s):  
LUKAS R.C. DEKKER ◽  
BART GERRITSE ◽  
AVRAM SCHEINER ◽  
LILIAN KORNET
Keyword(s):  
Nerve Stimulation ◽  
Phrenic Nerve ◽  
Phrenic Nerve Stimulation
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