SHOCK Differential Diagnosis and Hemodynamic Monitoring By Dr

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: <110 mm. Hg • Sinus tachycardia: >90 beats/min • Respiratory rate: <7 or >29 breaths/min • Urine Output: <0. 5 cc/kg/hr • Metabolic acidemia: [HCO 3]<31 m. Eq/L or base deficit>3 m. Eq/L • Hypoxemia: 0 -50 yr: <90 mm. Hg; 51 -70 yr: <80 mm. Hg; >71 yo<70 mm. Hg; • 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 1. Disruption of the microvascular endothelium 2. Cutaneous arteriolar dilation and increased capillary permeability Causes: 1. Anaphylaxis, drug, toxin reactions 2. Trauma: crush injuries, major fractures, major burns. 3. 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: 1. Cardiomyopathies: myocardial ischemia, myocardial infarction, cardiomyopathy, myocardiditis, myocardial contusion 2. Mechanical: cardiac valvular insufficiency, papillary muscle rupture, septal defects, aortic stenosis 3. Arrythmias: bradyarrythmias (heart block), tachyarrythmias (atrial fibrillation, atrial flutter, ventricular fibrillation) 4. 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 P 2 gallop, low BP, oliguria

NEUROGENIC SHOCK Mechanism: Loss of autonomic innervation of the cardiovascular system (arterioles, venules, small veins, including the heart) Causes: 1. Spinal cord injury 2. Regional anesthesia 3. Drugs 4. 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!