[Autonomic hyperreflexia induced by sacral root stimulation is detected by spectral analysis of the EEG].
OBJECTIVE
To compare spectral analysis of the electrocardiogram (ECG) with mean arterial pressure (MAP) and heart rate (HR) monitoring in the detection of autonomic hyperreflexia (AHR) induced by sacral root stimulation.


METHODS
Ten spinal cord injured patients scheduled for implantation of a sacral root stimulator for bladder retention were included. Under target controlled anesthesia with propofol 4 micro g*mL(-1) and remifentanil 4 ng*mL(-1), the patients were placed in the knee chest position. The sacral roots were exposed by laminectomy (L2-S1) and their function assessed by electrostimulation under urodynamic and cardiovascular monitoring. Online power spectrum densities were calculated from the ECG R-R interval by the MemCalc(TM) software using the maximum entropy method. Low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.4 Hz) spectra were associated with sympathetic and parasympathetic activities respectively. The most extreme value of each variable was noted before and during each stimulation. A difference ( triangle up ) of more than 10% signified AHR. The comparison ( triangle up LF vs triangle up MAP and triangle up HF vs triangle up HR) was done by a concordance test with a kappa coefficient (k): -1 = total discordance to 1 = total concordance.


RESULTS
AHR was detected in six patients as an increase in LF and MAP (n = 4); an increase in LF, HF, MAP with a decrease in HR (n = 2). The detection delay was 5.3 +/- 1 sec (LF, HF) and 10.4 +/- 1.2 sec (MAP and HR). Concordance was 85% (LF vs MAP: k = 0.7) and 90% (HF vs HR: k = 0.8).


CONCLUSIONS
AHR induced by sacral root stimulation is detected by spectral analysis of the ECG earlier than MAP and HR. Other studies are needed to confirm these results.
Sesay
Musa
M
Du Département d'Anesthésie-réanimation 3, Service de Neurochirurgie A, et Service de Rééducation neurologique, Centre Hospitalier Universitaire Pellegrin, Bordeaux France. musa.scsay@chu-bordeaux.fr
Vignes
Jean-Rodolphe
JR
Liguoro
Dominique
D
Crozat
Philippe
P
Boulard
Géry
G
Guerin
Jean
J
Barat
Michel
M
Maurette
Pierre
P
D000293:Adolescent; D000328:Adult; D018686:Anesthetics, Intravenous; D020211:Autonomic Dysreflexia / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D004558:Electric Stimulation; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007796:Laminectomy; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010880:Piperidines; D015742:Propofol; D012021:Reflex, Abnormal / Q000502:physiology*; D000077208:Remifentanil; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D013126:Spinal Nerve Roots / Q000502:physiology*; D014549:Urinary Incontinence / Q000628:therapy; D014563:Urodynamics
D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol