fNIRS brain measures of ongoing nociception during surgical incisions under anesthesia

Abstract

Significance : Functional near-infrared spectroscopy (fNIRS) has evaluated pain in awake and anesthetized states. Aim : We evaluated fNIRS signals under general anesthesia in patients undergoing knee surgery for anterior cruciate ligament repair. Approach : Patients were split into groups: those with regional nerve block (NB) and those without (non-NB). Continuous fNIRS measures came from three regions: the primary somatosensory cortex (S1), known to be involved in evaluation of nociception, the lateral prefrontal cortex (BA9), and the polar frontal cortex (BA10), both involved in higher cortical functions (such as cognition and emotion). Results : Our results show three significant differences in fNIRS signals to incision procedures between groups: (1) NB compared with non-NB was associated with a greater net positive hemodynamic response to pain procedures in S1; (2) dynamic correlation between the prefrontal cortex (PreFC) and S1 within 1 min of painful procedures are anticorrelated in NB while positively correlated in non-NB; and (3) hemodynamic measures of activation were similar at two separate time points during surgery (i.e., first and last incisions) in PreFC and S1 but showed significant differences in their overlap. Comparing pain levels immediately after surgery and during discharge from postoperative care revealed no significant differences in the pain levels between NB and non-NB. Conclusion : Our data suggest multiple pain events that occur during surgery using devised algorithms could potentially give a measure of “pain load.” This may allow for evaluation of central sensitization (i.e., a heightened state of the nervous system where noxious and non-noxious stimuli is perceived as painful) to postoperative pain levels and the resulting analgesic consumption. This evaluation could potentially predict postsurgical chronic neuropathic pain.

Comparison of cerebral metabolic rate of oxygen, blood flow, and bispectral index under general anesthesia

“…18,[85][86][87][88][89][90] However, these studies focused either on pre-and postsurgery assessments 90 or on the effect of the induction of anesthesia while focusing on various procedures. [91][92][93][94][95] One recent study by Zavriyev et al, 96 using both NIRS (a frequency domain system) and DCS, was employed during surgery in anesthetized patients but did not include LOC and ROC periods. In their study, the authors have concluded that this type of platform is effective in optimizing cerebral perfusion by comparing the CBF changes during hypothermic circulatory arrest alone and with retrograde or with antegrade cerebral perfusion.…”

“…Other studies employed standard NIRS quantifying oxyhemoglobin and deoxyhemoglobin concentrations which is difficult to quantitatively compare with our study. 17,93,97 For example, Liang et al 97 employed a research device based on continuous-wave NIRS to measure the propofol induced changes during LOC and ROC, but only reported values related to changes in HbO 2 , Hhb, THC, and one parameter related to the cardiac pulsation in arbitrary units. Therefore, only the trends are actually comparable to our findings.…”

Functional near‐infrared spectroscopy guided mapping of frontal cortex, a novel modality for assessing emergence delirium in children: A prospective observational study

“…However, fNIRS records and processes the changes at a higher frequency in smaller areas which enables it to detect regional activation and deactivation of neuronal activity 19 . It has been used to assess nociception during painful stimuli and surgical incisions under anesthesia 20,21 . Several studies 22–24 have investigated the use of fNIRS to monitor brain activity during emergence from anesthesia.…”

Can pain under anesthesia be measured? Pain-related brain function using functional near-infrared spectroscopy during knee surgery

“…The patients were then induced using a standard anesthetic regimen, where patients were premedicated with intravenous 2 mg midazolam and induced using propofol (median 200 mg [min 150 mg to max 300 mg]) along with fentanyl or sufentanil. The detailed anesthetic protocol of this patient cohort is discussed in our prior papers 30 , 31 . In addition to general anesthesia, peripheral nerve block with ropivacaine was administered to the adductor canal on the ipsilateral limb of 11 patients using the guidance of an ultrasound.…”

“…The detailed anesthetic protocol of this patient cohort is discussed in our prior papers. 30,31 In addition to general anesthesia, peripheral nerve block with ropivacaine was administered to the adductor canal on the ipsilateral limb of 11 patients using the guidance of an ultrasound. A lateral femoral cutaneous nerve block was added to the adductor canal block in one patient.…”