TY - JOUR
T1 - Quantitative assessment of somatosensory-evoked potentials after cardiac arrest in rats
T2 - Prognostication of functional outcomes
AU - Madhok, Jai
AU - Maybhate, Anil
AU - Xiong, Wei
AU - Koenig, Matthew A.
AU - Geocadin, Romergryko G.
AU - Jia, Xiaofeng
AU - Thakor, Nitish V.
N1 - Funding Information:
This work was supported, in part, by grants RO1 HL071568 from the National Institutes of Health (JM, RGG, XJ, NVT) and 09SDG1110140 from the American Heart Association (XJ) . The remaining authors have not disclosed any potential conflicts of interest.
PY - 2010/8
Y1 - 2010/8
N2 - Objective: High incidence of poor neurologic sequelae after resuscitation from cardiac arrest underscores the need for objective electrophysiological markers for assessment and prognosis. This study aims to develop a novel marker based on somatosensory evoked potentials (SSEPs). Normal SSEPs involve thalamocortical circuits suggested to play a role in arousal. Due to the vulnerability of these circuits to hypoxic-ischemic insults, we hypothesize that quantitative SSEP markers may indicate future neurologic status. Design: Laboratory investigation. Setting: University Medical School and Animal Research Facility. Subjects: Sixteen adult male Wistar rats. Interventions: None. Measurements and Main Results: SSEPs were recorded during baseline, during the first 4 hrs, and at 24, 48, and 72 hrs postasphyxia from animals subjected to asphyxia-induced cardiac arrest for 7 or 9 mins (n = 8/group). Functional evaluation was performed using the Neurologic Deficit Score (NDS). For quantitative analysis, the phase space representation of the SSEPs-a plot of the signal vs. its slope-was used to compute the phase space area bounded by the waveforms recorded after injury and recovery. Phase space areas during the first 85-190 mins postasphyxia were significantly different between rats with good (72 hr NDS ≥50) and poor (72 hr NDS <50) outcomes (p =.02). Phase space area not only had a high outcome prediction accuracy (80-93%, p <.05) during 85-190 mins postasphyxia but also offered 78% sensitivity to good outcomes without compromising specificity (83-100%). A very early peak of SSEPs that precedes the primary somatosensory response was found to have a modest correlation with the 72 hr NDS subscores for thalamic and brainstem function (p =.066) and not with sensory-motor function (p =.30). Conclusions: Phase space area, a quantitative measure of the entire SSEP morphology, was shown to robustly track neurologic recovery after cardiac arrest. SSEPs are among the most reliable predictors of poor outcome after cardiac arrest; however, phase space area values early after resuscitation can enhance the ability to prognosticate not only poor but also good long-term neurologic outcomes.
AB - Objective: High incidence of poor neurologic sequelae after resuscitation from cardiac arrest underscores the need for objective electrophysiological markers for assessment and prognosis. This study aims to develop a novel marker based on somatosensory evoked potentials (SSEPs). Normal SSEPs involve thalamocortical circuits suggested to play a role in arousal. Due to the vulnerability of these circuits to hypoxic-ischemic insults, we hypothesize that quantitative SSEP markers may indicate future neurologic status. Design: Laboratory investigation. Setting: University Medical School and Animal Research Facility. Subjects: Sixteen adult male Wistar rats. Interventions: None. Measurements and Main Results: SSEPs were recorded during baseline, during the first 4 hrs, and at 24, 48, and 72 hrs postasphyxia from animals subjected to asphyxia-induced cardiac arrest for 7 or 9 mins (n = 8/group). Functional evaluation was performed using the Neurologic Deficit Score (NDS). For quantitative analysis, the phase space representation of the SSEPs-a plot of the signal vs. its slope-was used to compute the phase space area bounded by the waveforms recorded after injury and recovery. Phase space areas during the first 85-190 mins postasphyxia were significantly different between rats with good (72 hr NDS ≥50) and poor (72 hr NDS <50) outcomes (p =.02). Phase space area not only had a high outcome prediction accuracy (80-93%, p <.05) during 85-190 mins postasphyxia but also offered 78% sensitivity to good outcomes without compromising specificity (83-100%). A very early peak of SSEPs that precedes the primary somatosensory response was found to have a modest correlation with the 72 hr NDS subscores for thalamic and brainstem function (p =.066) and not with sensory-motor function (p =.30). Conclusions: Phase space area, a quantitative measure of the entire SSEP morphology, was shown to robustly track neurologic recovery after cardiac arrest. SSEPs are among the most reliable predictors of poor outcome after cardiac arrest; however, phase space area values early after resuscitation can enhance the ability to prognosticate not only poor but also good long-term neurologic outcomes.
KW - cardiac arrest
KW - eectrophysiology
KW - functional outcomes
KW - prognosis
KW - quantitative neural monitoring
KW - somatosensory evoked potentials
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U2 - 10.1097/CCM.0b013e3181e7dd29
DO - 10.1097/CCM.0b013e3181e7dd29
M3 - Article
C2 - 20526197
AN - SCOPUS:77954951735
SN - 0090-3493
VL - 38
SP - 1709
EP - 1717
JO - Critical care medicine
JF - Critical care medicine
IS - 8
ER -