Acute Care Workshop Dr Stephanie Sim Dr Sharon Christie Dr James Shaw Dr Lysa Owen Plan for today Learning Objectives Powerpoint presentation (on Blackboard) Demonstration of ABCDE Split into 2 groups Simulation Break at half time then swap Outcomes Acute care Workshop Describe the pathophysiology of hypoxia and hypotension Identify when a patient is acutely unwell Demonstrate ability to assess an acutely unwell patient using ABCDE Initiate appropriate management Demonstrate awareness of specific treatment regimens Hypoxia Oxygen cascade • Series of steps: atmospheric air • pO2 at any stage mitochondria in subsequent steps 25 Dry atmospheric gas, (~21) 20 15 pO2 (kPa) Humidified tracheal gas, (~19.8) Alveolar gas, (~14) Arterial blood, (~13.3) 10 Capillary blood, (~7) 5 Mitochondria, (~4) 0 Remember Context is really important…. A patient with ‘normal values’ when breathing at a rate of 40 bpm, is not as well as someone breathing at a rate of 12bpm A patient with Sats of 96% on 60% O2 is not as well as someone breathing air with the same O2 sats! A patient with PaO2 of 9kPa is getting better if it was 8 before and he is on the same concentration of O2,but getting worse if it was previously 10kPa! Blood pressure Related to Arterial & venous system with organ autoregulation Blood Pressure Cardiac Output (CO) X Systemic vascular resistance (SVR) Heart Rate X Stroke Volume Blood pressure Related to Arterial & venous system with organ autoregulation Blood Pressure Myocardial contractility ↓↓ CARDIOGENIC SHOCK Afterload ↓↓ SEPSIS/ ANAPHYLAXIS/ NEUROGENIC Cardiac Output (CO) X Systemic vascular resistance (SVR) Heart Rate X Stroke Volume Preload ↓↓HYPOVOLAEMIA/ HAEMORRHAGE Blood pressure THEREFORE Blood Pressure depends on Circulating blood volume ↓ in hypovalaemia/ haemorrhage Pump function ↓ in cardiogenic shock Systemic vascular resistance ↓ in sepsis ↓ in anaphylaxis Response to shock Tachycardia, Tachypnoea Progressive peripheral vasoconstriction (if possible) Shift to anaerobic metabolism for hypoxic cells, then lose the ability to generate ATP, loss of electrical gradient and cell death Causes of Shock Haemorrhagic (70Kg man) Class I Class II Class III Class IV Blood loss (ml) Up to 750 750-1500 1500-2000 >2000 Blood loss (% volume) Up to 15% 15-30% 30-40% >40% Pulse rate <100 >100 >120 >140 Blood pressure Normal Normal Decreased Decreased Pulse pressure Normal or increased Decreased Decreased Decreased Respiratory Rate 14-20 20-30 30-40 >35 Urine Output ml/hr >30 20-30 5-15 Negligible CNS/Mental status Slightly anxious Mildly anxious Anxious, confused Confused, lethargic Signs of shock Tachycardia, tachypnoea and vasoconstriction => Diagnosis of shock until proven otherwise (relying on BP drop delays diagnosis) Urine output – indicator of renal blood flow Relative to normal (kids, young adults, elderly) Varying ability to mount response (B blocker, Ca channel blocker, paced, etc) Should be >0.5ml/Kg/hour Acid Base Abnormality Respiratory alkalosis initially> Metabolic Acidosis Assessment of shock Airway Breathing – give O2, RR, SpO2, Breath Sounds Circulation – stem bleeding/obtain adequate iv access/assess tissue perfusion (P,BP,CRT) ?Fluids required (likely to be) Disability – AVPU, BM, Pupils Exposure – Complete examination re possible cause, temp, TPAR ?Catheterisation Fluid Homeostasis Normal 70 Kg male = 42litre (60%) Water Extracellular Intracellular Fluid (ICF) 28 litres Fluid (ECF) 9.4 litres 4.6 litres Interstitial Plasma Normal Physiology Compartment volume maintained by Oncotic pressure (retains fluid) Hydrostatic pressure (forces fluid out of vessel) Osmotic gradients Electrolyte pumps Types of fluid replacement Crystalloids Colloids Blood Crystalloids Eg. Dextrose, Saline, Hartmans True solutions - substances which will diffuse through a semi-permeable membrane Pros/Cons: Easily available Cheap Variable volume of distribution (can end up in undesirable spaces!) Colloids Eg. Gelofusine, “glue” – Greek Substance which does not diffuse through a semipermeable membrane. Large particles (protein or carbohydrate) that are suspended in water Pros/Cons : Stays in intravascular space Relatively expensive Risk of anaphylaxis No proven benefit over saline in hypovolaemia Blood Pros/Cons : Well recognised Replaces ‘like with like’ Carries oxygen well! Expensive Risk of transfusion reactions Infection risk etc Distribution of Fluids 5%Dextrose (essentially WATER) Circulation Interstitial Fluid ICF ECF 0.9% Saline Blood Colloid (expands plasma volume due to oncotic pressure) Main points Recognise patient is unwell Treat early (ideally before hypoxic, hypotensive) Optimise what you can (ABCDE) *Remember Oxygen* General measures to improve blood pressure *Fluids* ( in almost all cases) Inotropes Specific measures to treat cause Monitor response Urine output, ABGs Blood pressure/ cardiac monitor Central lines etc Etc Any Questions? Outcomes Acute care Workshop Describe the pathophysiology of hypoxia and hypotension Identify when a patient is acutely unwell Demonstrate ability to assess an acutely unwell patient using ABCDE Initiate appropriate management Demonstrate awareness of specific treatment regimens