Metabolic response of patients to surgery

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Metabolic response of patients to surgery
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Case Study No. 1

• Male 65, hepatitis B carrier, 60kg
• 6-cm tumor in right lobe of liver, cirrhosis
• Right hepatic lobectomy
• blood loss 600ml
• no blood transfusion
• operation duration 6 hours
• Postop ICU care
• nutritional support
• oxygen therapy
• Home on postop day 7
• Weight loss of 7 kg

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Case Study No. 2

• Female 18, crush injury by car
• Shock
• Laparotomy
• lacerated right lobe of liver, successful
  hepatectomy
• blood transfusion 40 units
• Postop ICU care
• Remained febrile and tachycardiac
• Day 2 renal failure, requiring hemodialysis
• Day 5 bronchopneumonia
• Day 7 severe jaundice
• Day 9 hypotension
• Day 10 died from multi-organ failure

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Questions

• Why does a healthy person having a smooth
  recovery from a major operation lose body weight?
  Is debility after a major operation inevitable?
• Why does an apparently successful operation lead
  to multi-organ failure and mortality?

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Metabolic response of body to operation

• Bodys response to ensure survival from acute
  stress and recovery
• Magnitude dependent on degree of trauma and stress

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Stress during operation

• Skin incision
• Bleeding
• Hypothermia
• Bacterial contamination
• Exposure of viscera to air

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Phases of metabolic response

• Ebb phase
• phase of metabolic response to acute stress
• Flow phase
• phase of metabolic response after operation
• Anabolic phase
• recovery from operation

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Ebb phase
Phenomenon
Effect
? blood glucose ? lactate ?free fatty acids
? catecholamine ? glucagon
? cardiac output
? oxygen consumption
Below normal core temperature
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Outcome of patient in the ebb phase

• Succumb from lack of oxygen and nutrient supply
  to major organs
• Survive if prompt resuscitation is given

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Flow phase

• Metabolic response aims at wound healing
• Wound
• skin, fascia, anastomosis
• Wound dehiscence
• potentially fatal

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Wound healing

• Removal of debris, bacteria by macrophages
• Formation of new blood vessels, collagen and
  epithelium

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Prerequisite for perfect wound healing

• Supply of nutrients
• amino acid, glucose, fatty acid
• Supply of oxygen

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Supply of nutrients

• Glycogen store in liver and muscle
• Mobilization of amino acids from muscle and fatty
  acids from body fat
• ? weight loss

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Ill effects of mobilization of amino acids from
muscle

• Malaise, muscle weakness
• Immunosuppression
• Predisposition towards bronchopneumonia
• Mortality from infection

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Hypermetabolism

• Clinical manifestation
• increased heart or pulse rate
• increased respiratory rate
• fever
• Purpose
• to increase blood flow to wound and vital organs

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Cytokines production

• IL1, IL6, TNF released by macrophages accumulated
  in wound
• Important for inflammatory response and promotion
  of wound healing
• Spillage into systemic circulation
• systemic inflammatory response
• perpetuation of hypermetabolism
• multi-organ failure

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Flow phase
Phenomenon
Effect
? consumption of glucose, FFA, amino acid
? catecholamine ? glucagon ? cortisol ? insulin
N or ? glucose N or ? FFA normal lactate
? cardiac output
? CO2 production
? O2 consumption
? core body temperature
? heat production
? aldosterone ? ADH
fluid retention
IL1, IL6, TNF spillage from wound
systemic inflammatory response
multi-organ failure
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Metabolic response to surgery

• Beneficial for recovery
• Cost may be substantial

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Comparison of metabolic response between ebb and
flow phase
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Comparison of metabolic response between ebb and
flow phase (cont)
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Anabolic phase

• Recovery
• restoration of lean body mass, weight and well
  being

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Metabolic response
Sequence of events
acute stress
surgical problem ? infection

operation

bleeding tissue trauma bacterial
contamination necrotic debris
Ebb phase
mortality
food deprivation
local inflammatory response
hypermetabolism
wound pain
Flow phase
muscle wasting immunosuppression organ failure
infection
wound healing
immobility
Anabolic phase
recovery
mortality
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Strategy to attenuate metabolic response to
surgeryPrinciples

• No effective strategy to attenuate metabolic
  response
• Supportive measures are available
• Perfect surgery is essential

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Strategy to attenuate metabolic response to
surgeryDuring ebb phase

• Prompt fluid and blood replacement to maintain
  blood pressure
• Adequate oxygen supply and ventilation
• Cardiovascular support by inotropes
• Antibiotics

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Strategy to attenuate metabolic response to
surgeryDuring flow phase

• Nutritional support
• Warm room temperature
• Mobilization
• Hemodialysis
• Timely surgery for complication

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Determinants of survivalFactors
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http//www.hku.hk/hrmsfst
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Determinants of survival

• Magnitude of surgery and systemic inflammatory
  response induced
• Physiological reserve of the major organs
• Promptness of supportive treatment