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Quantitative EMG-monitoring in anesthesia and in intensive care
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F307 SOMATOSENSORYEVOKED POTENTIALS FOLLOWING STIMULATION OF THE LATERAL FEMORAL CUTANEOUSNERVE
STURM, U., FLUGEL, K.A., SKIBA, N., Department of Neurology, U n i v e r s i t y , Erlangen, FRG Lesions of the N. cutaneous femoris l a t e r a l i s causing meralgia paresthetica are d i f f i c u l t to prove with electrodiagnostic aids. Direct nerve conduction measurement is in many cases not useful, as i t may not be possible to be performed even in normal cases. Moreover, nerve compression in many cases seems to be localized proximally from the parts of the nerve accessible in neurography. Somatosensory evoked p o t e n t i a l s (Cz'-Fz) were investigated with proximal s t i m u l a t i o n at a point approximately 10 cm beneath the spina i l i a c a ant. and with s t i m u l a t i o n at a more d i s t a l point in the area of the nerve. In normal controls the proximally evoked scalp p o t e n t i a l s showed a f a i r l y constant p o s i t i v e peak (P33) with an average latency of 32,5 msec. (s=0,92) at the r i g h t and 32,3 msec. (s=0,69) at the l e f t side ( r i g h t - l e f t difference 1,0 msec). With d i s t a l s t i m u l a t i o n the latency of the i n i t i a l p o s i t i v e peak (P38) was 37,8 msec (s=1,42) on the r i g h t and 37.7 (s=0,85) on the l e f t side. A negative peak (proximal SSEP=44,7 msec, d i s t a l SSEP=49,6 msec) was less constant. The mean CV determined from P33 - P38 was 45,7 msec. In some patients with u n i l a t e r a l meralgia paresthetica abnormalities of the SSEP were found on the affected side, which, however, were not homogeneous.
F308 QUANTITATIVEEMG-MONITORINGIN ANESTHESIA AND IN INTENSIVE CARE SULG, I.A. and PALOHEIMO, M., Department of C l i n i c a l Neurophysiology in Trondheim, Norway, and Department of Anesthesiology, U n i v e r s i t y Hospital, Helsinki, Finland The need of m u l t i v a r i a b l e monitoring in anesthesia is generally recognized because of imperative need for continuous information about v i t a l functions in r i s k y conditions. Therefore, a new system f o r m u l t i v a r i a b l e neuromonitoring has been developed. EMG, spontaneous as well as stimulated, can be recorded p a r a l l e l to monitoring of EEG and endtidal CO~. Spontaneous muscle tone can be recorded and q u a n t i f i e d continuously as well ~s muscle responses on supramaximal stimulation in t r a i n s of four stimuli (TOF). The measured values of integrated EMG values are displayed continuously simultaneously with mean values of EEG-frequency and amplitude, and of the endtidal CO~. This novel monitoring equipment has been evaluated for anesthesia and in{ensive care at several u n i v e r s i t y - h o s p i t a l s in d i f f e r e n t countries. Following benefits have been demonstrated: 1) anesthesia level is reflected in the spontaneous muscle tone as well as in the EEG. 2) The grade of neuromuscular r e l a x a t i o n is reflected in TOF trends. 3) adequate v e n t i l a t i o n can be guided. 4) the continuous p r i n t - o u t from the monitor is a valuable chronological documentation. By means of t h i s monitoring equipment i t w i l l also be easier to evaluate the therapeutic and technical improvements in anesthesiology as well as in c r i t i c a l care.
F307 SOMATOSENSORYEVOKED POTENTIALS FOLLOWING STIMULATION OF THE LATERAL FEMORAL CUTANEOUSNERVE
STURM, U., FLUGEL, K.A., SKIBA, N., Department of Neurology, U n i v e r s i t y , Erlangen, FRG Lesions of the N. cutaneous femoris l a t e r a l i s causing meralgia paresthetica are d i f f i c u l t to prove with electrodiagnostic aids. Direct nerve conduction measurement is in many cases not useful, as i t may not be possible to be performed even in normal cases. Moreover, nerve compression in many cases seems to be localized proximally from the parts of the nerve accessible in neurography. Somatosensory evoked p o t e n t i a l s (Cz'-Fz) were investigated with proximal s t i m u l a t i o n at a point approximately 10 cm beneath the spina i l i a c a ant. and with s t i m u l a t i o n at a more d i s t a l point in the area of the nerve. In normal controls the proximally evoked scalp p o t e n t i a l s showed a f a i r l y constant p o s i t i v e peak (P33) with an average latency of 32,5 msec. (s=0,92) at the r i g h t and 32,3 msec. (s=0,69) at the l e f t side ( r i g h t - l e f t difference 1,0 msec). With d i s t a l s t i m u l a t i o n the latency of the i n i t i a l p o s i t i v e peak (P38) was 37,8 msec (s=1,42) on the r i g h t and 37.7 (s=0,85) on the l e f t side. A negative peak (proximal SSEP=44,7 msec, d i s t a l SSEP=49,6 msec) was less constant. The mean CV determined from P33 - P38 was 45,7 msec. In some patients with u n i l a t e r a l meralgia paresthetica abnormalities of the SSEP were found on the affected side, which, however, were not homogeneous.
F308 QUANTITATIVEEMG-MONITORINGIN ANESTHESIA AND IN INTENSIVE CARE SULG, I.A. and PALOHEIMO, M., Department of C l i n i c a l Neurophysiology in Trondheim, Norway, and Department of Anesthesiology, U n i v e r s i t y Hospital, Helsinki, Finland The need of m u l t i v a r i a b l e monitoring in anesthesia is generally recognized because of imperative need for continuous information about v i t a l functions in r i s k y conditions. Therefore, a new system f o r m u l t i v a r i a b l e neuromonitoring has been developed. EMG, spontaneous as well as stimulated, can be recorded p a r a l l e l to monitoring of EEG and endtidal CO~. Spontaneous muscle tone can be recorded and q u a n t i f i e d continuously as well ~s muscle responses on supramaximal stimulation in t r a i n s of four stimuli (TOF). The measured values of integrated EMG values are displayed continuously simultaneously with mean values of EEG-frequency and amplitude, and of the endtidal CO~. This novel monitoring equipment has been evaluated for anesthesia and in{ensive care at several u n i v e r s i t y - h o s p i t a l s in d i f f e r e n t countries. Following benefits have been demonstrated: 1) anesthesia level is reflected in the spontaneous muscle tone as well as in the EEG. 2) The grade of neuromuscular r e l a x a t i o n is reflected in TOF trends. 3) adequate v e n t i l a t i o n can be guided. 4) the continuous p r i n t - o u t from the monitor is a valuable chronological documentation. By means of t h i s monitoring equipment i t w i l l also be easier to evaluate the therapeutic and technical improvements in anesthesiology as well as in c r i t i c a l care.