By Dr. Ishara Maduka M.B.B.S.(Colombo) Shock Differential Diagnosis and Hemodynamic Monitoring By Dr. Ishara Maduka M.B.B.S.(Colombo)

Shock Shock is a Cardiovascular Derangement. 1. Deliver Oxygen and Metabolic Substrates 2. Remove Products of Cellular Metabolism 3. Thermoregulation Definition: A physiological state characterized by a significant, systemic reduction in tissue perfusion, resulting in decreased tissue oxygen delivery and insufficient removal of cellular metabolic products, resulting in tissue injury.

Classification of Shock Hypovolemic Septic/Inflammatory Cardiogenic (Intrinsic, compressive & Obstructive) Neurogenic Anaphylactic

Clinical Markers of Shock Brachial systolic blood pressure: <110mmHg Sinus tachycardia: >90 beats/min Respiratory rate: <7 or >29 breaths/min Urine Output: <0.5cc/kg/hr Metabolic acidemia: [HCO3]<31mEq/L or base deficit>3mEq/L Hypoxemia: 0-50yr: <90mmHg; 51-70yr: <80mmHg; >71yo<70mmHg; Cutaneous vasoconstriction vs. vasodilation. Mental Changes: anxiousness, agitation, indifference, lethargy, obtundation

Hypovolemic Shock Decreased preload->small ventricular end-diastolic volumes -> inadequate cardiac generation of pressure and flow Causes: -- bleeding: trauma, GI bleeding, ruptured aneurysms, hemorrhagic pancreatitis -- protracted vomiting or diarrhea -- adrenal insufficiency; diabetes insipidus -- dehydration

Hypovolemic Shock Signs & Symptoms: Hypotension, Tachycardia, Oliguria, Low volume Pulses. Markers: monitor UOP,CVP, BP, HR, Hct,CO, lactic acid and PCWP Treatment: ABCs, IVF (crystalloid), Transfusion Stem ongoing Blood Loss Patients on β-blockers, w/ spinal shock & athletes may not be tachycardic

Septic/Inflammatory Shock Mechanism: release of inflammatory mediators leading to Disruption of the microvascular endothelium Cutaneous arteriolar dilation and increased capillary permeability Causes: Anaphylaxis, drug, toxin reactions Trauma: crush injuries, major fractures, major burns. infection/sepsis: G(-/+ ) speticemia, pneumonia, peritonitis, meningitis, cholangitis, pyelonephritis, necrotic tissue, pancreatitis, wet gangrene, toxic shock syndrome, etc.

Septic/Inflammatory Shock Signs: Early– warm peripheries with vasodilatation, often adequate urine output, febrile, tachypnoeic. Late-- vasoconstriction, hypotension, oliguria, altered mental status.

Cardiogenic Shock Mechanism: Intrinsic abnormality of heart -> inability to deliver blood into the vasculature with adequate power Causes: Cardiomyopathies: myocardial ischemia, myocardial infarction, cardiomyopathy, myocardiditis, myocardial contusion Mechanical: cardiac valvular insufficiency, papillary muscle rupture, septal defects, aortic stenosis Arrythmias: bradyarrythmias (heart block), tachyarrythmias (atrial fibrillation, atrial flutter, ventricular fibrillation) Obstructive disorders: PE, tension peneumothorax, pericardial tamponade, constrictive pericaditis, severe pulmonary hypertension

Cardiogenic Shock Characterized by high preload (CVP) with low CO Signs: Dyspnea, rales, loud P2 gallop, low BP, oliguria

Neurogenic Shock Mechanism: Loss of autonomic innervation of the cardiovascular system (arterioles, venules, small veins, including the heart) Causes: Spinal cord injury Regional anesthesia Drugs Neurological disorders

Neurogenic Shock Characterized by loss of vascular tone & reflexes. Signs: Hypotension, Bradycardia, Accompanying Neurological deficits.

Monitoring Adjuncts in Shock Sphyngmomanometry Pulse Oximeter Arterial Line Central Venous Line (Triple Lumen, Pulmonary Artery Catheter)

Questions List the types of shock. List the clinical features of shock. Briefly explain the pathophysiology of each type of shock.

Thank You!