Physiological Responses to Surgery & Trauma
•Als PPTX, PDF herunterladen•
42 gefällt mir•16,944 views
A brief outline of the changes that occur in homeostasis & metabolism as a normal response to surgical intervention and how to compensate for them.
Empfohlen
Weitere ähnliche Inhalte
Was ist angesagt?
Was ist angesagt? (20)
Andere mochten auch
Andere mochten auch (20)
Ähnlich wie Physiological Responses to Surgery & Trauma
Ähnlich wie Physiological Responses to Surgery & Trauma (20)
Kürzlich hochgeladen
Kürzlich hochgeladen (20)
Physiological Responses to Surgery & Trauma
- 1. Muhammad Shoyab 1 5th Year MBBS Sir Salimullah Medical College May 05, 2009 Revised : July 2015
- 2. Surgery is a major stress . . . 2
- 3. . . . that not only overwhelms the patient’s psychology . . . 3
- 4. . . . but also overburdens physiology & homeostasis. 4
- 5. But is this what we want? 5
- 6. The answer is NO B&L 6
- 7. The aim of modern surgical practice is to ensure stress-free peri-operative care. B&L 7
- 8. which means . . . Iatrogenically created imbalances corrected by therapeutic intervention rather than overburdening homeostasis B&L 8
- 9. The stress response is a neuroendocrine process. CSDT 9
- 10. With metabolic & biochemical components 10 Stress Response Metabolic Biochemical Fluid & Electrolytes
- 13. Proteolysis Lipolysis Glycogenolysis Decreased peripheral glucose uptake (insulin resisance) Neoglucogenesis CSDT Summary of Metabolic Effects B&L 13
- 14. This is known as the acute phase reaction or the catabolic phase. It lasts for 24 – 48 hours. B&L Objective : To conserve volume and energy to combat the stress. 14
- 15. In addition to metabolic, the stress response also produces biochemical changes Best Practice & Research Clinical Anaesthesiology http://www.sciencedirect.com Stress Response Metabolic Biochemical Fluid & Electrolytes 15
- 16. ALDOSTERONE S Y M P A T H E T I C C H A I N Injury Sensory Nerves Nociceptors ADRENAL ADH PITUITARYAnaesthetics Vasodilation ECV falls Inflammation IL-1 , TNF Increased vascular permeability Albumin escapes into ISF Water osmoses to ISF Pre-op fasting / fluid loss Perioperative evaporation TBW falls RAA Axis Best Practice & Research Clinical Anaesthesiology http://www.sciencedirect.com 16 BIOCHEMICAL CHANGES
- 17. OLIGURIA ADH 17
- 18. OLIGURIA ADHThus, salt (NaCl) and water are retained avidly in the first few days. Best Practice & Research Clinical Anaesthesiology http://www.sciencedirect.com 18
- 19. Hence, no extra sodium is needed in the first 24 – 48 hours. Churchill 19
- 20. Inflammation IL-1 , TNF Increased vascular permeability Increased cellular permeability Na enters cells Fall of serum sodium In reality, total body sodium is conserved or even overloaded, but serum sodium level appears low. So, this is called pseudohyponatraemia. Best Practice & Research Clinical Anaesthesiology http://www.sciencedirect.com 20
- 21. This is why, administration of sodium is restricted over the first few days after surgery, to avoid further overloading of sodium. Protein catabolism is accompanied by potassium efflux. CSDT 21
- 22. Proteins maintain the intracellular negative charge. Loss of proteins from the cell creates an electrical imbalance . . . . . . which is balanced by potassium efflux. This may result in hyperkalaemia. This potassium is lost in exchange of sodium during the sodium retention phase. Best Practice & Research Clinical Anaesthesiology http://www.sciencedirect.com 22
- 23. B&L However, the catabolic phase is soon overtaken by anabolism. 23
- 24. During the anabolic phase, glycogen and protein are resynthesized. This causes rapid reuptake of K+. This may lead to hypokalaemia unless carefully supplemented. Best Practice & Research Clinical Anaesthesiology http://www.sciencedirect.com 24
- 25. Hence, potassium supplementation must be done carefully – no excess, no deficit. Best Practice & Research Clinical Anaesthesiology http://www.sciencedirect.com 25
- 27. • Adequate fluid therapy to maintain the effective circulatory volume while avoiding interstitial fluid overload • Minimal preoperative fasting • Adequate analgesia • Early post-operative mobilization • Early return to oral feeding Best Practice & Research Clinical Anaesthesiology http://www.sciencedirect.com Ways to Reduce Stress 27
Hinweis der Redaktion
- The surgical process constitutes a major stress, not only on the psychology and economy of the patient, but also on the body’s homeostatic mechanism.
- The surgical process constitutes a major stress, not only on the psychology and economy of the patient, but also on the body’s homeostatic mechanism.
- The surgical process constitutes a major stress, not only on the psychology and economy of the patient, but also on the body’s homeostatic mechanism.
- The surgical process constitutes a major stress, not only on the psychology and economy of the patient, but also on the body’s homeostatic mechanism.
- This means that the iatrogenically created imbalances must be corrected by therapeutic intervention, rather than overburdening the body’s homeostatic mechanism. An understanding of the way the body responds to the stress will enable us to identify the changes that occur and adopt appropriate corrective mechanisms.
- The response to surgery and trauma is a neuroendocrine process, involving both the peripheral and central nervous systems and the entire endocrine axis starting from the hypothalamus and the pituitary to the thyroid, adrenals and pancreas.
- The response to surgery and trauma is a neuroendocrine process, involving both the peripheral and central nervous systems and the entire endocrine axis starting from the hypothalamus and the pituitary to the thyroid, adrenals and pancreas.
- As soon as the first few centimetres of skin are incised, impulses pass along the sensory nerves up the spinal cord and stimulate both the sympathetic system as well as the endocrine axis. As a result, the pituitary gland releases GH, thyroxine comes from the thyroid gland, cortisol and adrenaline from the adrenal and glucagon and insulin from the pancreas.
- This picture shows the effect of these hormones on the body’s metabolic status. Thyroxine and cortisol act on skeletal muscles to induce the breakdown of muscle protein. These are released as free AA into the blood. GH, TH, cortisol, EP and NEP break down the body’s fat stores, releasing large amounts of FFA into the systemic circulation. At the same time, glucagon acts on the liver and releases the glycogen stores in the form of glucose. The released AA and FFA are taken up by the liver.
- Thus, if we summarise the metabolic effects of stress, we have proteolysis, lipolysis, and glycogenolysis.
- These constitute the acute phase reaction or the catabolic phase of the stress response. It lasts for 24 – 48 hours and serves to conserve volume and energy to combat the stress.
- In addition to the metabolic effects that we have discussed till now, the stress response also involves important changes in the fluid and electrolyte balance of the body.
- Earlier, we have discussed how the painful stimuli passing along sensory nerves and up the spinal cord induce the sympathetic and endocrine axes to release hormones that affect the body’s metabolic processes. In this slide, we have shown the secretion of some hormones affecting the fluid and electrolyte balance. The vasodilatory effect of some anaesthetic agents, plus the fluid loss due to vomiting, bleeding and evaporation during the operation all contribute to a reduction in the ECV. This stimulates the pituitary gland to secrete ADH. At the same time, the fall in ECV activates the RA mechanism. The RA axis and the sympathetic stimulation causes the adrenal to secrete aldosterone. Thus, we have two very important hormones : ADH and aldosterone. ADH level remains elevated upto 4 days after surgery. (Dr. Bob Richardson, Toronto General Hospital)
- The effect of ADH is well-known to us all. It acts on the renal system to increase the reabsorption of water, leading to oliguria. Likewise, aldosterone leads to retention of salt and water in exchange for K.
- Simply providing the daily physiological requirement is sufficient.
- In addition to the metabolic effects and the salt and water retention that we have already covered, the inflammatory reaction accompanying the stress response induces the secretion of inflammatory mediators such as IL-1, TNF alpha, etc. These mediators have widespread effects, including increased vascular and cell membrane permeability. We all know that the concentration of sodium is much higher outside the cell than inside. The increased permeability now allows Na ions to leave the circulation and enter the cell. This produces a state of apparent sodium deficit in the serum. This is called pseudohyponatraemia because in reality total body sodium is conserved or even overloaded, but sodium level in blood and urine appear to be low. ADH level remains elevated upto 4 days after surgery. (Dr. Bob Richardson, Toronto General Hospital)
- Earlier, we have become familiar with the fact that the stress response involves breakdown of muscle protein, which are then released into the general circulation as AA.
- We know that proteins maintain the intracellular negative charge. Loss of proteins means loss of negative charges, creating an electrical imbalance. Which is balanced by the efflux of potassium from the cell to the outside. This may lead to hyperkalaemia. The potassium thus released into the circulation is lost in exchange of sodium during the sodium retention phase.
- Resynthesis of proteins inside the cell increases intracellular negative charge, which has to be balanced by rapid uptake of K.
- At the beginning of our discussion, we talked about stress free care. I will finish by mentioning the factors that influence the level of stress
- And ways to reduce the stress.
- This means that the iatrogenically created imbalances must be corrected by therapeutic intervention, rather than overburdening the body’s homeostatic mechanism. An understanding of the way the body responds to the stress will enable us to identify the changes that occur and adopt appropriate corrective mechanisms.
- This means that the iatrogenically created imbalances must be corrected by therapeutic intervention, rather than overburdening the body’s homeostatic mechanism. An understanding of the way the body responds to the stress will enable us to identify the changes that occur and adopt appropriate corrective mechanisms.