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
Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), am ...
,
physiology
Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical ...
and
surgery
Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...
.
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 responses triggered by the procedures are compared. Absent any other difference, 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.
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Methods
Examples of used parameters are
blood pressure
Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" r ...
,
heart rate
Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...
,
heart rate variability
Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats. It is measured by the variation in the beat-to-beat interval.
Other terms used include: "cycle length variability", "R–R variabi ...
,
photoplethysmography
A photoplethysmogram (PPG) is an optically obtained plethysmogram that can be used to detect blood volume changes in the microvascular bed of tissue. A PPG is often obtained by using a pulse oximeter which illuminates the skin and measures cha ...
and
skin conductance
Electrodermal activity (EDA) is the property of the human body that causes continuous variation in the electrical characteristics of the skin. Historically, EDA has also been known as skin conductance, galvanic skin response (GSR), electrodermal ...
. Essentially, physiologic parameters are measured in order to assess sympathetic tone as a surrogate measure of stress.
Intraoperative neurophysiological monitoring
Intraoperative neurophysiological monitoring (IONM) or intraoperative neuromonitoring is the use of electrophysiological methods such as electroencephalography (EEG), electromyography (EMG), and evoked potentials to monitor the functional integri ...
can also be used.
Examples of commonly used biomarkers are
adrenaline
Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands and ...
,
cortisol
Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone.
It is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal cortex in the adrenal gland ...
,
interleukin
Interleukins (ILs) are a group of cytokines (secreted proteins and signal molecules) that are expressed and secreted by white blood cells (leukocytes) as well as some other body cells. The human genome encodes more than 50 interleukins and related ...
s,
noradrenaline
Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad'', ...
and
vasopressin
Human vasopressin, also called antidiuretic hormone (ADH), arginine vasopressin (AVP) or argipressin, is a hormone synthesized from the AVP gene as a peptide prohormone in neurons in the hypothalamus, and is converted to AVP. It then travel ...
.
History
Loss of nitrogen (urea) was observed already in the 1930s in fracture patients by the Scottish physician
David Cuthbertson
Sir David Paton Cuthbertson, CBE, FRSE (9 May 1900 – 15 April 1989) was a Scottish physician, biochemist, medical researcher and nutritionist who was a leading authority on metabolism. The Rowett Research Institute became one of the world ...
. The reason for the patients' catabolic response was not understood at the time, but later attention was turned to the stress reaction caused by the surgery.
The evolutionary background is believed to be that a wounded animal increases its chance of survival by using stored energy reserves. The stress reaction thus initiates a catabolic state by an increased release of catabolic hormones. Additionally immunosuppressive hormones are also released.
In a surgery patient, the stress reaction is considered detrimental for wound healing. However, surgical stress reduced mortality from endotoxin shock. Today, development of new surgical techniques and anaesthetic protocols aim to minimise the surgical stress reaction.
[{{cite journal , last1=Kehlet , first1=H , title=Multimodal approach to control postoperative pathophysiology and rehabilitation , journal=British Journal of Anaesthesia , date=May 1997 , volume=78 , issue=5 , pages=606–617 , doi=10.1093/bja/78.5.606, pmid=9175983 ]
References
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Stress (biology)
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Anesthesia