Sepsis & Shock Slides PDF

What is Sepsis? =============== **The Body's Extreme Systematic Response to an infection** **[SEPSIS] is a life-threatening condition that occurs when an existing infection triggers a chain of physiological reactions throughout the body** Step-by-Step on the Pathophysiology (how the normal physio...

What is Sepsis? =============== **The Body's Extreme Systematic Response to an infection** **[SEPSIS] is a life-threatening condition that occurs when an existing infection triggers a chain of physiological reactions throughout the body** Step-by-Step on the Pathophysiology (how the normal physiology changes) ======================================================================= 1. Person gets an infection (From anything-it could be a cut somewhere) 2. This triggers an immune response (Like when we have a cold our glands in neck bloat-immune response): **But in Sepsis**, there's an **immunologic overactivity** 3. (Hyperactive immune response): Excess Leukocytes (White blood cell responsible for fighting infections and bacteria-that's why lots of White blood cells in bloods). 4. So because of this excessive response-instead of it doing the job locally (at the site), it becomes **systemic** (in the circulation). 5. When this happens, the capillaries become more **dilated** & **permeable** (This means they can sieve out fluid from inside the vessel and leak out to outside the vessel. Think about it: If fluid is not inside the vessels but outside of them, then will this not impact on the preload (i.e STROKE VOLUME)? 6. This will compromise blood flow to organs and tissues. **Intravascular volume** decreases and abruptly drops too low to maintain tissue perfusion. 7. Now let's turn this to another perspective: Remember the **Extrinsic pathway** of clotting cascade?? If we are losing blood volume (Like a major Haemorrhage)-and tissue damage from metabolic acidosis and vascular permeability, we kick-start an abnormal **clotting cascade**. 8. This means **DIC (Disseminated Intravascular Coagulopathy)** = cells respond by triggering micro clots, causing blockage and also restricting **oxygen** availability to tissues even further (Oxygen was already limited because of the loss of volume carrying the oxygen) 9. Now without Oxygen- (Glucose + Oxygen = ATP+ C02+H20) you got (**Glucose= ATP+ Lactic Acid**). Because of the loss of 02 and production of Lactic Acid this become anaerobic Metabolism (it would be anaerobic respiration if someone wasn't breathing properly, but this is loss of 02 in the circulation rather than primarily from breathing distress); the resulting lactic acid build-up causes **metabolic acidosis.** This leads to cell death and Tissue death-Then **MULTIPLE ORGAN FAILURE** 10. Now yet another thing that happens: Adrenaline release occurs in response to marked vascular dilation and inadequate vascular volume, causing tachycardia. Look at the chart below: I wonder how Adrenaline causes vaso-constriction sometimes and then effected HR this time. It's a BETA response!! +-----------------------+-----------------------+-----------------------+ | **ORGAN** | **SYMPATHETIC | **PARASYMPATHETIC | | | STIMULATION** | STIMULATION** | | | | | | | **(alpha or beta | **(act at Muscarinic | | | receptor)** | Receptors)** | +=======================+=======================+=======================+ | HEART | **INCREASE** Heart | **DECREASE** Heart | | | Rate | Rate | | | | | | | (Beta 1 and Beta 2) | **DECREASE** force of | | | | contraction | | | **INCREASE** force of | | | | contraction | | | | | | | | (Beta 1 and Beta 2) | | +-----------------------+-----------------------+-----------------------+ | ARTERIES | **CONSTRICTION** | **DILATION** | | | (alpha 1) | | | | | | | | **DILATION** (beta 2) | | +-----------------------+-----------------------+-----------------------+ | VEINS | **CONSTRICTION** | **DILATION** | | | (alpha 1) | | | | | | | | **DILATION** (beta 2) | | +-----------------------+-----------------------+-----------------------+ | LUNG | Bronchial muscle | **CONSTRICTION** | | | **DILATION** | | | | | | | | (Beta 2) | | +-----------------------+-----------------------+-----------------------+ **Blood gas shows:** Test Value Normal values pH 7.23 7.35-7.45 acidic PaO2 9.85 11-13 kPa slightly low O2 in blood PaCO2 3.2 4.7-6.0 kPa low CO2 in blood BE -16.7 +/-- 2 How much alkaline needed to restore HCO3 12.6 22-26 mmol/l low bicarbonate (metabolic problem!) Lac 6.2 \