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critical illness and metabolism ICRC 2012.pptx
- 1. Dr.Kayanoosh Kadapatti MD,DNB (Med) EDIC Head,Department of Critical Care Jehangir Hospital,Pune
- 2. The evolution of a discreet injury into a syndrome that spans neulologic, endocrine and metabolic systems, sometimes leading to radical changes in end organ dysfunction…….. Fundamental characteristic of critical illness Many metabolic changes describe the syndrome but without interpretation these observations merely remain isolated facts unable to guide clinical management.
- 3. In his framework, Cuthbertson said the physiology of critical illness was an adaptive response . Metabolic changes from normal are necessary to heal serious injury. This concept informs the scientific inquiry into which processes are biologically useful or harmful and which should be supplemented and suppressed……… nutrition, care of endocrine systems and intervention in immunologic signaling.
- 4. The predictable pattern in response to injury The role of interventions that depend on this pattern Diagnostic utility of comparing patient’s clinical data to the stress response pattern.
- 5. Hypermetabolism is a hallmark of critical illness…………. Ebb and flow in which a period of hypoperfusion to maintain survival followed by a healing period.
- 6. Cardiac output oxygen delivery substrate delivery stress hormones Time course varies by stress: Classically 6-7 days Energy Expenditure Ebb Phase Shock and hypoperfusion Flow Phase hypermetabolism Peak amplitude influenced by the type of stressor
- 7. • Characterized by hypovolemic shock • Priority is to maintain life/homeostasis Cardiac output Oxygen consumption Blood pressure Tissue perfusion Body temperature Metabolic rate Cuthbertson DP, et al. Adv Clin Chem 1969;12:1-55 Welborn MB. In: Rombeau JL, Rolandelli RH, eds. Enteral and Tube Feeding. 3rd ed. 1997
- 8. • Catecholamines • Glucocorticoids • Glucagon • Release of cytokines, lipid mediators • Acute phase protein production Cuthbertson DP, et al. Adv Clin Chem 1969;12:1-55 Welborn MB. In: Rombeau JL, Rolandelli RH, eds. Enteral and Tube Feeding. 3rd ed. 1997
- 9. Glucose and lactate metabolism increases in brain tissue during stress so also amino-acid metabolism………. Encephalopathy of critical illness due to – ◦ Increase of Aromatic amino acids and metabolites ◦ Impaired Global cerebral function …..causing delirium to coma
- 10. Stress increases the peripheral tissue oxygen consumption…… icn.COP, dec. PVR, Redistribution of blood O2 consumption is highest in the tissues with the highest level of leucocytes suggests that delivery is increased to feed cells that repair tissue and control infection. Capillary beds leak…..loss of tight junctions… formation of peripheral oedema, Decrease O2 delivery in vital tissues, myocardial damage,
- 11. Body Water Tissue oedema and intravascular resuscitation increase body water and patient gains weight. ECW and EVV expand with loss of ICF….free movement of water from the IVS to the EVS.This has implication on the electrolyte balance.
- 12. Electrolytes: Hypernatremia: insensible water loss, diuretics Hyponatremia: water retention, dilutional Hypokallemia, hypomagnesemia, hyperphosphatemia: intracellular ions Hypophosphataemia: exhaustion of phosphate, refeeding syndrome.
- 13. Fatty Deposits Liver & Muscle (glycogen) Muscle (amino acids) Fatty Acids Glucose Amino Acids Endocrine Response
- 14. 10 20 30 40 28 24 20 16 12 8 4 0 Nitrogen Excretion (g/day) Days Long CL, et al. JPEN 1979;3:452-456
- 15. Adapted from Long CL, et al. JPEN 1979;3:452-456 Basal Metabolic Rate Cirugía mayor Cirugía electiva Infección Sepsis grave Quemadura moderada a grave Nitrogen Loss in Urine Major Surgery Elective Surgery Infection Severe Sepsis Moderate to Severe Burn
- 16. The sensitivity of pulmonary gas exchange to systemic perturbations reflects how often pulmonary insufficiency accompanies the stress response. Inc O2 consumption and CO2 production put greater demand on the pulmonary system. Tacypnoea, Type 1 and Type 11 respiratory failure ensue. Inc. capillary permeability Perivascular fluid flux wet lungs (NCPO) Inflammatory infiltration Aspiration, altered immune function : inc risk of pulmonary infection
- 17. Inc. Protein turnover in the GIT causes intestinal oedema and villous atrophy Worsening stress gastric and large bowel illeus. Enteral nutrition thus suffers Impaired excretion of bilirubin and metabolites.
- 18. Redistribution of bloodflow to the peripheries causes renal perfusion to be “stolen”… Decreasing perfusion, circulating mediators…syndrome of oliguria, tubular dysfunction. Metabollically active tubular cells suspend function till stress resolved……extreme condition is AKI.
- 19. The stress response involves a complex immunologic and neurologic signalling.
- 20. Cells of the innate immune system recognize microorganisms and initiate responses through pattern- recognition receptors called toll like receptors (TLRs).
- 22. TLR4 mutations have been identified in humans and may make persons more susceptible to infection. [J Exp Med 1993;177:89-97., Nat Genet 2000;25:187-91.]
- 23. Triggering Receptor expressed on myeloid cells A receptor of the immunoglobulin superfamily, that regulates the function of myeloid cells activates neutrophils and monocytes/macrophages Amplifies the response of Toll like receptors and potentiates secretion of pro inflammatory cytokines J Infect Dis,2003; 187(Suppl.2): S397–401
- 26. Inhibition of NF- B activation restores systemic hypotension, ameliorates septic myocardial dysfunction and vascular derangement, inhibits multiple proinflammatory gene expression, diminishes intravascular coagulation, reduces tissue neutrophil influx, prevents microvascular endothelial leakage. prevents multiple organ injury improves survival in rodent models of septic shock Am J Physiol Lung Cell Mol Physiol 290: L622-L645, 2006 8/24/2023 26 •
- 32. Stress Hyperglycemia: ◦ Dt inc cortisol, catecholamines and glucagon ◦ Altered peripheral response to insulin Vasopressin secretion from posterior pituitary increases in Shock but may become depleted dt neuroendocrine exhaustion. Sick euthyroid syndrome Disorders of sleep cycle Altered immunologic function.
- 33. Hendon etal : Betablockers in burnt children to reduce muscle mass….NEJM 2001 Blood sugar control in the ICU Corticosteroids in Septic shock In one study supplementation of Growth Hormone increased mortality. Dotrecogen alpha ……….misdirected attempts to alter stress metabolism can have adverse events.
- 34. Available data present a small perspective on the diagnostic and therapeutic implications of stress metabolism. Although variable ,the pattern includes increased oxygen delivery, catabolism, and evolving organ dysfunction. The astute clinician should be able to diagnose new injuries like secondary infection make timely interventions and anticipate the need for resuscitation or diuresis and whether to escalate or taper therapies…. Signals that hypermetabolism is decreasing indicate source control of inflammatory response….. Concept of Chronic critical illness.
- 35. The stress response concept is a valuable framework for organising care for the critically ill patient. Recognising worsening or worsening regulatory inflammatory signals should guide care. Must anticipate deviations from the predicted pattern.
- 36. Critical illness increases global metabolism as an adaptive response to facilitate healing after injury. Stress response : the ebb and flow phase followed by anabolism protein building …….. is manifested in every organ in the body. A good intensivist can exploit their knowledge of the stress response by predicting the pattern , mapping patient physiology to the expected changes and making diagnostic and therapeutic decisions based on expected trajectory or unexpected variation from the common stress response pattern.