Shock Dr. Faiez Alhmoud Department of Surgery Albashir Hospital Objectives To develop an understanding of the definition and pathophysiology of shock To develop an understanding and overview of the different types of shock To develop a systematic approach to the detection and management of shock To develop a deeper understanding of sepsis and septic shock To know how to decrease mortality in shock Definition of Shock What is shock? Inadequate tissue perfusion Why should you care? High mortality - 20-90% Early on the effects of O2 deprivation on the cell are REVERSIBLE Early intervention reduces mortality Understanding Shock Shock results from an inadequate perfusion of the body’s cells with oxygenated blood. Which means : Systemic imbalance between O2 supply & demand Which leads to: Cellular dysfunction and damage Organ dysfunction and damage Understanding Shock Tissue perfusion is driven by blood pressure! So……………… In other words, when the blood flow (pressure) and O2 delivery to the cell are too low, there will be shock! Understanding Shock -BP BP = CO x SVR BP = blood pressure CO = cardiac output SVR = systemic (peripheral) vascular resistance If the blood pressure is low, then either the: CO is low or the SVR is low Understanding Shock -VR SVR regulated by blood vessel tone. Dilatation opens blood vessels & increases volume to area but decreases return to heart Constriction decreases volume to area but increases return to heart Understanding Shock Stroke Volume Volume of blood pumped by the heart in one cycle What affect stroke volume ? Blood volume Rhythm problems Heart muscle problem Mechanical obstruction 1234- Understanding Shock Blood Volume What makes up the blood volume? 1234- Plasma RBCes Platelets WBCes What alters blood volume ? 1- Hemorrage 2- Plasma loss 3- Redistribution of extracellular volume Stages of shock Initial :The cells become leaky and switch to anaerobic metabolism. Non-progressive:(compensated stage) Attempt to correct the metabolic upset of shock Progressive: Eventually the compinsation will begin to fail Refractory : Organs fail and the shock can no longer be reversed. Early Stage of Shock Compensation (Maintain & Restore) 1- Tissue perfusion 2- Oxygenetion Symptoms - Almost asymptomatic •Pulse may be slightly elevated •Anxiety /Nervousness •Dizziness •Weakness •Faintness •Nausea & Vomiting •Thirst •Confusion •Decreased UO •Hx of Trauma / other illness •Vomiting & Diarrhoea •Chest Pain •Fevers / Rigors •SOB Non-Progressive shock : (Compensated) MAP Drops by 10-15mm Hg Kidneys Release Renin Hormonal changes:ADH, Aldosterone, epinephrine, norephinephrine Vasoconstriction:Vessels are clamping down Intermediate or Progressive Shock (Decompensated) The mechanisms compensate for worsening shock will begin to fail. Cellular dysfunction begins to spiral out of control, metabolic acidosis worsens MAP drops more than 15mmHg Hypoxia Anoxia Ischemia Refractory; Irreversible Shock Lack of O2 < 70 Increase in toxins Difficult to recover from Enzyme activity increases Disintegrating any remaining organelles Tissue anoxia Generalized cellular death At this stage organs fail and the shock can no longer be reversed. Death occurs rapidly. Types of Shock Hypovolemic Blood VOLUME problem Cardiogenic Blood PUMP problem Distributive Blood VESSEL problem Obstructive Extracardiac pump FAILURE problem What Type of Shock is This? • 68 yo M with hx of HTN and DU presents to the ER with epigastric abdominal pain with radiation to his back and diziness. The pt is hypotensive, tachycardic, afebrile, and with cool skin. Hypovolemic Shock Hypo-volemic Shock• Non-hemorrhagic • • • • • Vomiting Diarrhea Bowel obstruction, pancreatitis Burns Neglect, environmental (dehydration) • Hemorrhagic • Trauma • GI bleed • Ectopic pregnancy, post-partum bleeding • Massive hemoptysis • AAA rupture Blood loss - Plasma Loss - ECF Loss causes ATLS classification of hemorrhagic shock Class Pulse BP CNS Status Urine Output Blood Loss I <100 Normal Slightly anxious >30ml/h <15% 750cc II >100 Normal Mildly anxious 15 -20 15%-30% 750-1500cc III >120 Decreased Confused 5 -15 30%-40% 1500-2500cc IV >140 Decreased Lethargic Nil >40% >2500cc In a normal adult, a tachycardia after blood loss indicates at least a 15% loss of blood volume (>750 mls) Evaluation of Hypovolemic Shock • • • • • • • As indicated CBC • CXR ABG/lactate • Pelvic x-ray Electrolytes • Abd. US (FAST) BUN, Creatinine • Abd/pelvis CT Coagulation studies • Chest CT Type and cross-match • GI endoscopy • Bronchoscopy • Vascular radiology Hypovolemic Shock- management • ABCs (Control any bleeding) • Establish 2 large bore IVs or a central line • Crystalloids • Normal Saline or Lactate Ringers • Up to 3 liters • PRBCs • O negative or cross matched • Arrange definitive treatment What Type of Shock is This? • An 81 yo F presents to the ED with chest infection and altered mental status. She is febrile to 39.4, hypotensive with a widened pulse pressure, tachycardic and with warm extremities Septic Sepsis • Two or more of SIRS criteria • • • • Temp > 38 or < 36 C HR > 90 RR > 20 WBC > 12,000 or < 4,000 • Plus the presumed existence of infection • Blood pressure can be normal! Sepsis,Severe Sepsis and Septic Shock Sepsis: Severe Sepsis: Septic Shock: Systemic host response to infection with SIRS Sepsis plus end-organ dysfunction or hypo perfusion Sepsis with hypotension, despite fluid resuscitation; evidence of inadequate tissue perfusion Septic Shock • Sepsis (remember definition?) • Plus refractory hypotension • After bolus of 20-40 mL/Kg patient still has one of the following: • SBP < 90 mm Hg • MAP < 65 mm Hg • Decrease of 40 mm Hg from baseline Septic Shock • Clinical signs: • Hyperthermia or hypothermia (Hot – early or cold - late phase) • Tachycardia • Wide pulse pressure • Low blood pressure (SBP<90) • Mental status changes • Beware of compensated shock! • Blood pressure may be “normal” Pathogenesis of Sepsis Nguyen H et al. Severe Sepsis and Septic-Shock: Review of the Literature and Emergency Department Management Guidelines. Ann Emerg Med. 2006;42:28-54. Ancillary Studies • • • • • • Cardiac monitoring Pulse oximetry CBC, coags, LFTs, lipase, KFT & UA ABG with lactate Blood culture x 2, urine culture CXR Treatment of Septic Shock • 2 large bore IVs • NS IVF bolus- 1-2 L wide open (if no contraindications) • Supplemental oxygen • Empiric antibiotics, based on suspected source, as soon as possible • Foley catheter (why do you need this?) Treatment of Sepsis • Antibiotics- Survival correlates with how quickly the correct drug was given • Cover gram positive and gram negative bacteria • Add additional coverage as indicated • Pseudomonas- Gentamicin or Cefepime • MRSA- Vancomycin • Intra-abdominal or head/neck anaerobic infectionsClindamycin or Metronidazole • Asplenic- Ceftriaxone for N. meningitidis, H. infuenzae • Neutropenic – Cefepime or Imipenem Persistent Hypotension • If no response after 2-3 L IVF, start a vasopressor (norepinephrine, dopamine, etc) and titrate to effect • Goal: MAP > 60 • Consider adrenal insufficiency: hydrocortisone 100 mg IV What Type of Shock is This? • A 34 yo F presents to the ER after dining at a restaurant where shortly after eating the first few bites of her meal, became anxious, diaphoretic, began wheezing, noted diffuse pruritic rash, nausea, and a sensation of her “throat closing off”. She is currently hypotensive, tachycardic and ill appearing with dyspnea. Anaphylactic Shock Anaphylactic Shock • What are some symptoms of anaphylaxis? • First- Pruritus, flushing, urticaria appear •Next- Throat fullness, anxiety, chest tightness, shortness of breath and lightheadedness •Finally- Altered mental status, respiratory distress and circulatory collapse Anaphylactic Shock - Common Features Angio-edema Broncho-constriction Vasodilatation Hypotension Urticareal rash Anaphylactic Shock… Diagnosis • Clinical diagnosis • Defined by airway compromise, hypotension, or involvement of cutaneous, respiratory, or GI systems • Look for exposure to drug, food, or insect bite • Labs have no role Anaphylactic Shock…. Treatment • ABC’s • Angioedema and respiratory compromise require immediate intubation or surgical airway • • • • IV line, cardiac monitor, pulse oximetry IVFs, oxygen Epinephrine**** Second line • Corticosteriods • H1 and H2 blockers Anaphylactic Shock…. Treatment • Epinephrine • 0.3 mg IM of 1:1000 (epi-pen) • Repeat every 5-10 min as needed • Caution with patients taking beta blockers- can cause severe hypertension due to unopposed alpha stimulation • Corticosteroids • Methylprednisolone 125 mg IV • Prednisone 60 mg PO • Antihistamines • H1 blocker- Diphenhydramine 25-50 mg IV • H2 blocker- Ranitidine 50 mg IV • Bronchodilators • Albuterol nebulizer • Atrovent nebulizer • Magnesium sulfate 2 g IV over 20 minutes Anaphylactic Shock…. Management • All patients who receive epinephrine should be observed for 4-6 hours • If symptom free, discharge home • If on beta blockers or h/o severe reaction in past, consider admission What Type of Shock is This? • A 41 yo M presents to the ER after a car accident complaining of decreased sensation below his waist and is now hypotensive, bradycardic, with warm extremities Neurogenic Neurogenic Shock • Neurogenic shock is caused by the loss of sympathetic control (tone) of resistance vessels, which leads to decreased tissue perfusion and initiation of the shock response. • Results in hypotension and bradycardia • Neurogenic shock can be caused by spinal cord injury (above T1), CNS injury, general or spinal anesthesia, pain, and anxiety. • Onset is within minutes and may last weeks . • Skin is warm and dry Neurogenic Shock…..Treatment • A,B,Cs • Remember c-spine precautions • Fluid resuscitation • Keep MAP at 85-90 mm Hg for first 7 days • Thought to minimize secondary cord injury • If crystalloid is insufficient use vasopressors • Search for other causes of hypotension • Methylprednisolone is controversial & given early and in high doses • For bradycardia • Atropine • Pacemaker What Type of Shock is This? • A 55 yo M with hx of HTN, DM presents with “crushing” substernal pain, diaphoresis, hypotension, tachycardia and cool, clammy extremities Cardiogenic Shock • Defined as: shock resulting from inadequate cardiac function • Signs: • • • • • Cool, mottled skin Tachypnea, tachycardia Hypotension Altered mental status Narrowed pulse pressure (WEAK) • Rales, murmur Cardiogenic Shock - Etiology WHAT CAUSES PUMP FAILURE ? Intrinsic Causes - Myocardial injury - Tachycardia - Valvular defect Extrinsic (Obstructive Shock) - Pericardial tamponade - Tension pneumothorax - Large pulmonary emblous Pathophysiology of Cardiogenic Shock • Often after ischemia, loss of LV function (Loss of 40% of LV function clinical shock ensues) • CO reduction = lactic acidosis, hypoxia • Stroke volume is reduced • Tachycardia develops as compensation • Ischemia and infarction worsens Ancillary Tests • EKG • CXR • CBC, cardiac enzymes, coagulation studies • Echocardiogram What Type of Shock is This? • A 24 yo M presents to the ED after an MVC c/o chest pain and difficulty breathing. On PE, you note the pt to be tachycardic, hypotensive, hypoxic, and with decreased breath sounds on left Obstructive Obstructive Shock Obstructive Shock • Tension pneumothorax • Air trapped in pleural space with 1 way valve, air/pressure builds up • Mediastinum shifted impeding venous return • Chest pain, SOB, decreased breath sounds • No tests needed! • Rx: Needle decompression, chest tube Obstructive Shock • Cardiac tamponade • Blood in pericardial sac prevents venous return to and contraction of heart • Related to trauma, pericarditis, MI • Beck’s triad: hypotension, muffled heart sounds, JVD • Diagnosis: large heart CXR, echo • Rx: Pericardiocentisis Obstructive Shock • Pulmonary embolism • Virscow triad: hypercoaguable, venous injury, venostasis • Signs: Tachypnea, tachycardia, hypoxia • Low risk: D-dimer, CT chest or VQ scan • Rx: Heparin, consider thrombolytics Obstructive Shock • Aortic stenosis • Resistance to systolic ejection causes decreased cardiac function • Chest pain with syncope • Systolic ejection murmur • Diagnosed with echo • Vasodilators (NTG) will drop pressure! • Rx: Valve surgery TO BE CONTINUED Clinical Assessment Is this shock ? Head & Neck = Pale ? Cyanosis? Dyspnea? LOC?, RR?, Peripheral pulses? Vital Signs Initially: HR inc; RR inc; diastolic BP inc slightly P02 > 95% Skin Color; Cap refill; Warm? Cool? Petech. Pt c/o being thirsty or dry mucous membr. Renal Drop in output (0.5ml/Kg/h) In infants :poor tone, weak cry, lethargy/ coma sunken or bulging fontanella) Shock •Do you remember how to quickly estimate blood pressure by pulse? • If you palpate a pulse, you know SBP is at least this number 60 70 80 90 Empiric Criteria for Shock 4 out of 6 criteria have to be met Ill appearance or altered mental status Heart rate >100 Respiratory rate > 22 (or PaCO2 < 32 mmHg) Urine output < 0.5 ml/kg/hr Arterial hypotension > 20 minutes duration Lactate > 4 LAB VALUES IN SHOCK H&H = decreased in hemorrhage WBC = increase in Septic & Anaphylactic shock Neutrophils = Acute infection Monocytes = Bacterial infection Eosinophils = Allergic response Kidney function Decreased perfusion = BUN & Creatinine, specific gravity & osmolality increase Cardiac enzymes (cardiogenic shock) LDH, CPK, SGOT increase Lactate Beta HCG +/- Cross Match Other investigations ECG Urinalysis CXR +/- Echo +/- FAST Treatment of Shock Start treatment immediately ABC’s “5 to 15” Airway Breathing Circulation Put the patient on a monitor if available Treat underlying cause Modified Trendelenberg ? Medications (BP medications Bronchodilators Steroids) LOOK, FEEL, LISTEN, REPORT Airway & Breathing • Give Oxygen Consider Intubation Is the cause quickly reversible? Generally no need for intubation 3 reasons to intubate in the setting of shock Inability to oxygenate Inability to maintain airway Work of breathing • Remember: intubation can worsen hypotension • Sedatives can lower blood pressure • Positive pressure ventilation decreases preload • May need volume resuscitation prior to intubation to avoid hemodynamic collapse Optimizing Circulation • DO NOT WAIT for hypotension and treat for the early signs of shock • Isotonic crystalloids • Titrated to: • CVP 8-12 mm Hg • Urine output 0.5 ml/kg/hr (30 ml/hr) • Improving heart rate • May require 4-6 L of fluids • No outcome benefit from colloids End Points of Resuscitation • Goal of resuscitation is to maximize survival and minimize morbidity • Use objective hemodynamic and physiologic values to guide therapy • Goal directed approach • • • • Urine output > 0.5 mL/kg/hr CVP 8-12 mmHg MAP 65 to 90 mmHg Central venous oxygen concentration > 70% Persistent Hypotension • • • • • • Inadequate volume resuscitation Pneumothorax Cardiac tamponade Hidden bleeding Adrenal insufficiency Medication allergy Practically Speaking…. Know how to distinguish different types of shock and treat accordingly Look for early signs of shock Monitor the patient using the HR, MAP, mental status, urine output SHOCK is not equal to hypotension Start antibiotics within an hour! Do not wait for cultures or blood work The End Any Question? Infusion Rates Access 18 g peripheral IV 16 g peripheral IV 14 g peripheral IV 8.5 Fr CV cordis Gravity 50 mL/min 100 mL/min 150 mL/min 200 mL/min Pressure 150 225 275 450 mL/min mL/min mL/min mL/min