Surgical stress

Surgical stress is the systemic response to surgical injury and is characterized by activation of the sympathetic nervous system, endocrine responses as well as immunological and haematological changes. Measurement of surgical stress is used in anaesthesia, physiology and surgery.

Analysis of the surgical stress response can be used for evaluation of surgical techniques and comparisons of different anaesthetic protocols. Moreover they can be performed both in the intraoperative or postoperative period. If there is a choice between different techniques for a surgical procedure, one method to evaluate and compare the surgical techniques is to subject one group of patients to one technique, and the other group of patients to another technique, after which the surgical stress response triggered by the procedure is compared. The technique with the least surgical stress response is considered the best for the patient.

Similarly, a group of patients can be subjected to a surgical procedure where one anaesthetic protocol is used, and another group of patients are subjected to the same surgical procedure but with a different anaesthetic protocol. The anaesthetic protocol that yields the least stress response is considered the most suitable for that surgical procedure.

It is generally considered or hypothesized that a more invasive surgery, with extensive tissue trauma and noxious stimuli, triggers a more significant stress response.

However, duration of surgery may affect the stress response which therefore may make comparisons of procedures that differ in time difficult.

Examples of used parameters are blood pressure, heart rate, heart rate variability, photoplethysmography and skin conductance. Essentially, physiologic parameters are measured in order to assess sympathetic tone as a surrogate measure of stress. Intraoperative neurophysiological monitoring can also be used. Examples of commonly used biomarkers are adrenalin, cortisol, interleukins, noradrenalin and vasopressin.

...
Wikipedia