ORGAN FAILURE Organ failure in ICU Can be
ORGAN FAILURE
Organ failure in ICU • Can be a consequence of direct injury (eg pneumonia/MI/toxin) • Can also occur as a consequence of shock with tissue ischaemia and dysfunction occurring as a consequence of hypoxia.
Indicators of organ failure Respiratory – Requiring supplementary oxygen +/ventilation Cardiovascular - Low blood pressure or on vasopressors/inotropes Renal – reduced or no urine output, raised serum creatinine Nervous System – Reduced conscious level Liver – Coagulopathy, low blood sugar, high lactate, encephalopathy, raised bilirubin (without other cause) Haematological – Low platelets, deranged coagulation tests (e. g. prothrombin time)
Multi-Organ Dysfunction Syndrome (MODS) is the term used to describe loss of physiologic reserve and progressive organ injury associated with critical illness.
Multiple Organ Dysfunction Syndrome • Shock causes hypoperfusion, lack of oxygen at a cellular level then leads to cellular dysfunction/death • Cellular dysfunction/death causes release of inflammatory cytokines and microvascular injury • This cascade then causes further cellular dysfunction and whole organ system failure ensues
Management of MODS Treat the underlying cause! Supportive: Oxygenation, ventilation Fluid/Inotropes/vasopressors Feeding Replacement Mechanical organ specific support (renal replacement therapy, extracorporeal hepatic support, Left-ventricular support, ECMO) Avoid the complications of prolonged ICU stay
General Supportive Measures • Feeding • Sedation and Invasive ventilation • Gastric protection • DVT prevention • Measures to limit nosocomial infection • Analgaesia
Specific Organ Support- Respiratory • Non Invasive Ventillation • BIPAP & CPAP • See subsequent respiratory lecture
Specific Organ Support- Respiratory Intermittent Positive Pressure Ventilation Pressure support ventilation Tracheostomy Slow weaning of ventilatory support
Specific Organ Support –ECMO • Extracorporeal Membrane Oxygentaion • Only used in acute, severe REVERSIBLE respiratory or cardiac failure, with a high risk of death, that is refractory to conventional management. • Only available in certain specialist centres • Blood is removed from the body, oxygenated by a machine, then returned. • Frequent and severe complications
Specific Organ Support- Cardiovascular • Limited options • Vasoactive agents • Intra-aortic balloon pump
Specific Organ Support- Renal failure is common and is often reversible when it occurs as a consequence of MODS. Renal replacement therapy involves mechanical replacement of renal function (essentially a ‘kidney machine’
Indications to commence Renal Replacement Therapy Symptomatic uraemia (encephalopathy, pericarditis, bleeding) Fluid overload Metabolic acidosis due to renal failure Resistant hyperkalaemia Non-renal certain toxins/drugs resistant hypernatraemia temperature control removal of inflammatory cytokines (no evidence-controversial)
Types of Organ Support • Renal – provide a temporary means of filtering or dialysing the blood in patients with renal failure (CVVHDF)
How RRT works
Types of Organ Support • Nervous system – a patient may need to be sedated (and thus intubated and ventilated): • or their own safety e. g. if encephalopathic • if they have a reduced GCS and may not be able to protect their own airway. • Temperature management post cardiac arrest • If they have a brain injury
Complications of prolonged ICU stay • Ventilator-associated pneumonia • Vascular catheter associated bloodstream infection • Catheter-associated urinary tract infection • Venous thromboembolism • ICU acquired weakness • Paralytic ileus • Ischaemia from arterial lines • Stress ulcers • Psychological sequelae and cognitive dysfunction
Prognosis in organ failure • Mortality ranges from 30% to 100% where mortality increases as the number of organs involved increases Mortality Number of organ systems involved
Summary • Multi-organ Dysfunction can be avoided by prompt treatment of shock and its causes. • Low urine output can be the first sign of organ dysfunction • Organ support has many complications • Multi-organ failure carries a high mortality
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