Physiological Responses to Surgery & Trauma
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Transcript of Physiological Responses to Surgery & Trauma
Physiological Responses to
Surgery & Trauma
Muhammad Shoyab
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5th Year MBBSSir Salimullah Medical College
May 05, 2009Revised : July 2015
Surgery is a major stress . . .
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. . . that not only overwhelms the patient’s psychology . . .
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. . . but also overburdens physiology & homeostasis.
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But is this what we want?
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The answer is NO
B&L6
The aim of modern surgical practice is to ensure
stress-free peri-operative care.
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which means . . .Iatrogenically created imbalances
corrected by therapeutic interventionrather than overburdening homeostasis
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The stress response is a neuroendocrine process.
CSDT9
With metabolic & biochemical components
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Stress Response
Metabolic
BiochemicalFluid &
Electrolytes
SYMPATHETIC CHAIN
CRHTRHGHRH
CORTISOL
ADRENALINE
GLUCAGON
ACTH THYROXINE
TSH
Injury
Sensory Nerves
THALAMUS
Nociceptors
ADRENAL
PANCREAS
HYPOTHALAMUS
THYROID
PITUITARY
B&LINSULIN
GROWTH HORMONE
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CSDT12
Metabolic Changes
ProteolysisLipolysisGlycogenolysisDecreased peripheral glucose uptake (insulin resisance)Neoglucogenesis
CSDT
Summary of Metabolic Effects
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This is known as the acute phase reaction or the catabolic phase.
It lasts for 24 – 48 hours.
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Objective : To conserve volume and energy to combat the stress.
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In addition to metabolic, the stress response also produces biochemical changes
Best Practice & Research Clinical Anaesthesiologyhttp://www.sciencedirect.com
Stress Response
Metabolic
Biochemical
Fluid & Electrolytes
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ALDOSTERONE
SYMPATHETIC CHAIN
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 Anaesthesiologyhttp://www.sciencedirect.com
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BIOCHEMICAL CHANGES
OLIGURIA
ADH
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OLIGURIA
ADHThus, salt (NaCl) and water are retained avidly in the first few days.
Best Practice & Research Clinical Anaesthesiologyhttp://www.sciencedirect.com
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Hence, no extra sodium is
needed in the first 24 – 48
hours.
Churchill19
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
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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.
CSDT21
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 Anaesthesiologyhttp://www.sciencedirect.com
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However, the catabolic phase is soon overtaken by anabolism.
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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 Anaesthesiologyhttp://www.sciencedirect.com
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Hence, potassium supplementation must be done
carefully – no excess, no deficit.
Best Practice & Research Clinical Anaesthesiologyhttp://www.sciencedirect.com
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Factors of Stress
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• 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 Anaesthesiologyhttp://www.sciencedirect.com
Ways to Reduce Stress
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Stress-free peri-operative care
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Stress-free peri-operative care
B&L29THANK YOU