Surgical stress, nociception

Perioperative management, Department of Anesthesiology

The occurrence of postoperative complications due to surgery affects not only the short-term prognosis but also the long-term prognosis of patients, so there is a need to suppress their occurrence. Although efforts have been made to improve the overall condition of patients before surgery, develop minimally invasive surgery, and implement early postoperative recovery programs, serious postoperative complications still occur in several percent to several tens of percent of patients. One of the factors that causes postoperative complications is the intensity of surgical stress, and we thought that suppressing the biological reaction to surgical stress through anesthesia management could contribute to suppressing postoperative complications. However, there has been no indicator to quantitatively monitor surgical stress during surgery.
In this study, we developed the Nociceptive Response (NR) index, which quantifies the strength of nociceptive stimuli during general anesthesia using heart rate (HR), systolic blood pressure (SBP), and perfusion index (PI) (Formula (1)). The change in the NR index in an actual clinical setting is shown in the figure. The purpose of this study is to clarify that anesthesia management that suppresses the NR index during surgery suppresses biological reactions due to surgical invasion and suppresses the onset of postoperative complications.

We have discovered the first mathematical formula that can objectively evaluate the strength of nociceptive stimuli during anesthesia.
In addition, it is now possible to display the strength of nociceptive stimulation during anesthesia in real time during surgery as a calculated numerical value, NR.

Since it uses normal monitor values, it is easy to obtain the NR value and can be applied to existing monitors, making it extremely versatile.
Retrospective evaluation is also possible using big data accumulated in anesthesia monitoring and recording devices.

General anesthesia presents the challenge of reducing risks to patients, such as the occurrence of postoperative complications.

• The anesthesiologist will administer the appropriate amount of anesthesia.
• General anesthesia management that suppresses the NR index value during surgery (NR-guided general anesthesia) contributes to preventing the onset of postoperative complications.

By quantifying "pain level," it is possible to provide appropriate analgesia to patients receiving intensive care.

Patent No. 6934251 "Apparatus and method for monitoring nociceptive stimulus response levels under anesthesia" (Registration date: August 25, 2021)

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