What constitutes Trauma?
- Major Surgery
- Major Burns
- Autoimmune response
Homeostatic control in trauma
Earlier it was thought that everyone has to go through these events, but by proper fluid, pain and nutritional management this can be avoided.
So how does metabolic response maintain homeostasis?
- Metabolic response tries to conserve fluid.
- Increase local blood flow and tissue perfusion.
- Provides adequate utilizable energy to injured tissue.
Mechanism of Metabolic Response-what stimulates it?
Body can compensate 500ml loss easily
- General anesthesia has little effect on inflammatory response.
- Depolarising Muscle relaxants like Succinylcholine increases muscle metabolism which increases creatinine kinase and muscle breakdown.
- Hypotensive anesthesia mimics blood loss and stimulates metabolic response.
Pathology of Metabolic response- what are the changes it causes?
Inflammatory reaction/ MODS/SIRS
Sympathetic and neuro-endocrine response
Acute phase protein reaction
Immune system activation
Body composition changes
Negative nitrogen balance leading to muscle loss.
Postop fatigue– in first month in 1/3rd of patients after major surgery.
Determinants of magnitude of metabolic response
- Magnitude of trauma
- Inter-individual variation mostly genetically influenced
- Ischemia reperfusion injuries—more blood more inflammatory cells
- Sepsis in GI surgery
- Pre-existent nutritional status
- Post-op complications
- Concurrent diseases- RA, IBS
- Smoking, nicotine up regulates pro-inflammatory cytokine production.
Modifying metabolic response
Reducing the stimulus
- Handle with care
- Soft tissue handling
- Reduce loss
- Avoid contamination with gut contents
- Careful suturing without strangulation
- Enteral nutrition support stimulates gut functions and thereby reducing translocation of bacterial products.
- Glutamine is a major fuel which improves muscle protein synthesis and abolishes catabolic response.
- Atleast 100gms/day needed to prevent ketosis.
- Intake during stress should be between 30-40% of total calories.
- Glucose intake should not exceed 5mg/kg/min
- Provides 20-35% of total calories.
- Maximum recommendation for intravenous lipid infusion: 1-1.5 g/kg/day
- Monitor triglyceride levels to ensure adequate lipid clearance.
- Comprises 20-30% of total calories during metabolic recovery.
- Requirements ranges from 1.2-2 g/kg/day
Epidural anesthesia reduces neuroendocrine, hyperglycemic and catabolic responses.
Selective digestive decontamination
- Done in major surgeries like cardiopulmonary bypass.
- Reducing the endotoxin and cytokine levels.
- Reduces prostaglandin secretion.
- Reduces body temperature.
- Reduces metabolic rate.
- Reduces magnitude of APP response.
- Reduces inflammatory response overall.
Given per or perioperatively reduces IL6, IL8 and TNFa production and thereby reducing the inflammatory response.