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

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.

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The action of the canine diaphragm on the lower ribs depends on activation

Journal of Applied Physiology ◽

10.1152/japplphysiol.00402.2011 ◽

2011 ◽

Vol 111 (5) ◽

pp. 1266-1271 ◽

Cited By ~ 11

Author(s):

André De Troyer

Keyword(s):

Nerve Stimulation ◽

Phrenic Nerve ◽

Muscle Activation ◽

Pleural Pressure ◽

Phrenic Nerve Stimulation ◽

Nerve Roots ◽

Neural Drive ◽

Airway Opening ◽

Phrenic Nerves ◽

Spontaneously Breathing

Conventional wisdom maintains that the diaphragm lifts the lower ribs during isolated contraction. Recent studies in dogs have shown, however, that supramaximal, tetanic stimulation of the phrenic nerves displaces the lower ribs caudally and inward. In the present study, the hypothesis was tested that the action of the canine diaphragm on these ribs depends on the magnitude of muscle activation. Two experiments were performed. In the first, the C5 and C6 phrenic nerve roots were selectively stimulated in 6 animals with the airway occluded, and the level of diaphragm activation was altered by adjusting the stimulation frequency. In the second experiment, all the inspiratory intercostal muscles were severed in 7 spontaneously breathing animals, so that the diaphragm was the only muscle active during inspiration, and neural drive was increased by a succession of occluded breaths. The changes in airway opening pressure and the craniocaudal displacements of ribs 5 and 10 were measured in each animal. The data showed that 1) contraction of the diaphragm causes the upper ribs to move caudally; 2) during phrenic nerve stimulation, the lower ribs move cranially when the level of diaphragm activation is low, but they move caudally when the level of muscle activation is high and the entire rib cage is exposed to pleural pressure; and 3) during spontaneous diaphragm contraction, however, the lower ribs always move cranially, even when neural drive is elevated and the change in pleural pressure is large. It is concluded that the action of the diaphragm on the lower ribs depends on both the magnitude and the mode of muscle activation. These findings can reasonably explain the apparent discrepancies between previous studies. They also imply that observations made during phrenic nerve stimulation do not necessarily reflect the physiological action of the diaphragm.

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Electrophysiological evaluation of phrenic nerve function in candidates for diaphragm pacing

Journal of Neurosurgery ◽

10.3171/jns.1980.53.3.0345 ◽

1980 ◽

Vol 53 (3) ◽

pp. 345-354 ◽

Cited By ~ 44

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.

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Phrenic nerve conduction times and twitch pressures of the human diaphragm

Journal of Applied Physiology ◽

10.1152/jappl.1985.58.5.1496 ◽

1985 ◽

Vol 58 (5) ◽

pp. 1496-1504 ◽

Cited By ~ 69

Author(s):

D. K. McKenzie ◽

S. C. Gandevia

Keyword(s):

Phrenic Nerve ◽

Simultaneous Recording ◽

Emg Activity ◽

Conduction Time ◽

Transdiaphragmatic Pressure ◽

Surface Electrodes ◽

Midclavicular Line ◽

Phrenic Nerves ◽

The Mean ◽

The Right

A multilumen catheter was modified to allow simultaneous recording of transdiaphragmatic pressure (Pdi) and the electromyographic (EMG) activity of the diaphragm. The catheter was used in 20 healthy males to measure the conduction time of the phrenic nerves and the twitch pressure of each hemidiaphragm during single supramaximal shocks delivered to the phrenic nerve in the neck. Diaphragmatic EMG was also recorded with surface electrodes at various sites on the chest wall. The mean conduction time to the crural fibers was 6.82 +/- 0.64 ms on the right and 7.93 +/- 0.85 ms on the left, whereas that to the costal fibers adjacent to the midclavicular line was 7.68 +/- 0.56 ms on the right and 7.92 +/- 0.92 ms on the left. Significant correlations were found between the conduction time of each phrenic nerve and the height and the age of the subjects. Conduction times measured at different EMG recording sites varied by as much as 2 ms. This variability, and that of previously reported values for phrenic conduction time, may be largely accounted for by differences in the conduction distances that were measured to each site in three cadavers. The evoked change in Pdi had a mean rise time of 92 ms and an amplitude of approximately 10 cmH2O.

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

Journal of Applied Physiology ◽

10.1152/jappl.1997.82.4.1190 ◽

1997 ◽

Vol 82 (4) ◽

pp. 1190-1199 ◽

Cited By ~ 60

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.

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Diaphragm EMG measured by cervical magnetic and electrical phrenic nerve stimulation

Journal of Applied Physiology ◽

10.1152/jappl.1998.85.6.2089 ◽

1998 ◽

Vol 85 (6) ◽

pp. 2089-2099 ◽

Cited By ~ 37

Author(s):

Y. M. Luo ◽

M. I. Polkey ◽

L. C. Johnson ◽

R. A. Lyall ◽

M. L. Harris ◽

...

Keyword(s):

Chest Wall ◽

Phrenic Nerve ◽

Nerve Conduction ◽

Compound Muscle Action Potential ◽

Normal Subjects ◽

Conduction Time ◽

Surface Electrodes ◽

Muscle Action Potential ◽

Electrode Positioning ◽

Phrenic Nerves

The purpose of the study was to compare electrical stimulation (ES) and cervical magnetic stimulation (CMS) of the phrenic nerves for the measurement of the diaphragm compound muscle action potential (CMAP) and phrenic nerve conduction time. A specially designed esophageal catheter with three pairs of electrodes was used, with control of electrode positioning in 10 normal subjects. Pair A and pair B were close to the diaphragm ( pair A lower than pair B); pair C was positioned 10 cm above the diaphragm to detect the electromyogram from extradiaphragmatic muscles. Electromyograms were also recorded from upper and lower chest wall surface electrodes. The shape of the CMAP measured with CMS (CMS-CMAP) usually differed from that of the CMAP measured with ES (ES-CMAP). Moreover, the latency of the CMS-CMAP from pair B (5.3 ± 0.4 ms) was significantly shorter than that from pair A (7.1 ± 0.7 ms). The amplitude of the CMS-CMAP (1.00 ± 0.15 mV) was much higher than that of ES-CMAP (0.26 ± 0.15 mV) when recorded from pair C. Good-quality CMS-CMAPs could be recorded in some subjects from an electrode positioned very low in the esophagus. The differences between ES-CMAP and CMS-CMAP recorded either from esophageal or chest wall electrodes make CMS unreliable for the measurement of phrenic nerve conduction time.

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Mechanism of the lung-deflating action of the canine diaphragm at extreme lung inflation

Journal of Applied Physiology ◽

10.1152/japplphysiol.01422.2011 ◽

2012 ◽

Vol 112 (8) ◽

pp. 1311-1316 ◽

Cited By ~ 7

Author(s):

Dimitri Leduc ◽

Matteo Cappello ◽

Pierre Alain Gevenois ◽

André De Troyer

Keyword(s):

Nerve Stimulation ◽

Phrenic Nerve ◽

Pleural Pressure ◽

Phrenic Nerve Stimulation ◽

Lung Volumes ◽

Lung Inflation ◽

Lower Lung ◽

Airway Opening ◽

Radiopaque Markers ◽

Phrenic Nerves

When lung volume in animals is passively increased beyond total lung capacity (TLC; transrespiratory pressure = +30 cmH2O), stimulation of the phrenic nerves causes a rise, rather than a fall, in pleural pressure. It has been suggested that this was the result of inward displacement of the lower ribs, but the mechanism is uncertain. In the present study, radiopaque markers were attached to muscle bundles in the midcostal region of the diaphragm and to the tenth rib pair in five dogs, and computed tomography was used to measure the displacement, length, and configuration of the muscle and the displacement of the lower ribs during relaxation at seven different lung volumes up to +60 cmH2O transrespiratory pressure and during phrenic nerve stimulation at the same lung volumes. The data showed that 1) during phrenic nerve stimulation at 60 cmH2O, airway opening pressure increased by 1.5 ± 0.7 cmH2O; 2) the dome of the diaphragm and the lower ribs were essentially stationary during such stimulation, but the muscle fibers still shortened significantly; 3) with passive inflation beyond TLC, an area with a cranial concavity appeared at the periphery of the costal portion of the diaphragm, forming a groove along the ventral third of the rib cage; and 4) this area decreased markedly in size or disappeared during phrenic stimulation. It is concluded that the lung-deflating action of the isolated diaphragm beyond TLC is primarily related to the invaginations in the muscle caused by the acute margins of the lower lung lobes. These findings also suggest that the inspiratory inward displacement of the lower ribs commonly observed in patients with emphysema (Hoover's sign) requires not only a marked hyperinflation but also a large fall in pleural pressure.

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

Journal of Applied Physiology ◽

10.1152/jappl.1989.67.4.1364 ◽

1989 ◽

Vol 67 (4) ◽

pp. 1364-1370 ◽

Cited By ~ 12

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.

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