Shock In Children

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Shock In Children

  1. 1. SHOCK IN CHILDREN
  2. 2. Definition <ul><li>Circulatory system failure to supply </li></ul><ul><li>oxygen and nutrients to meet cellular </li></ul><ul><li>metabolic demands </li></ul>
  3. 3. Other Definitions <ul><li>Blood Pressure </li></ul><ul><ul><li>BP = CO x SVR </li></ul></ul><ul><li>Cardiac Output </li></ul><ul><ul><li>CO = SV X HR </li></ul></ul><ul><li>Vascular Tone (SVR) </li></ul><ul><ul><li>Regulated by several mechanisms </li></ul></ul>
  4. 4. Oxygen Delivery <ul><li>DO 2 = CO x CaO 2 x 10 </li></ul><ul><ul><li>Remember: CO depends on HR, preload, afterload, and contractility </li></ul></ul><ul><li>CaO 2 = Hgb x 1.34 x SaO 2 + (PaO 2 x 0.003) </li></ul><ul><ul><li>Remember: hemoglobin carries more than 99% of oxygen in the blood under standard conditions </li></ul></ul>
  5. 5. Hemodynamics Textbook of Pediatric Advanced Life Support, 1988
  6. 6. Defending the blood pressure <ul><li>Neural Sympathetic </li></ul><ul><ul><li>Baroreceptors </li></ul></ul><ul><ul><ul><li>Carotid Body </li></ul></ul></ul><ul><ul><ul><li>Aortic Arch </li></ul></ul></ul><ul><ul><li>Volume receptors </li></ul></ul><ul><ul><ul><li>Right Atrium </li></ul></ul></ul><ul><ul><ul><li>Pulmonary vascular </li></ul></ul></ul><ul><ul><li>Chemoreceptors </li></ul></ul><ul><ul><ul><li>Aortic and carotid </li></ul></ul></ul><ul><ul><ul><li>Medullary </li></ul></ul></ul><ul><ul><li>Cerebral ischemic response </li></ul></ul><ul><li>Humoral </li></ul><ul><ul><li>Adrenal medulla </li></ul></ul><ul><ul><ul><li>Catecholamines </li></ul></ul></ul><ul><ul><li>Hypothalamopituitary response </li></ul></ul><ul><ul><ul><li>Adrenocorticotropic hormone </li></ul></ul></ul><ul><ul><ul><li>Vasopressin </li></ul></ul></ul><ul><ul><li>Renin-angiotensin-aldosterone system </li></ul></ul>
  7. 7. Cardiovascular function <ul><li>Cardiac Output </li></ul><ul><ul><li>Clinical Assessment </li></ul></ul><ul><ul><ul><li>peripheral perfusion, temperature, capillary refill, urine output, mentation, acid-base status </li></ul></ul></ul><ul><ul><li>CO = HR x SV </li></ul></ul><ul><ul><ul><li>HR responds the quickest </li></ul></ul></ul><ul><ul><ul><li>SV is a function of three variables </li></ul></ul></ul><ul><ul><ul><ul><li>preload, afterload, and myocardial contractility </li></ul></ul></ul></ul><ul><ul><ul><li>A noncompliant heart cannot increase SV </li></ul></ul></ul>
  8. 8. Stroke Volume <ul><li>Preload (LVEDV) </li></ul><ul><ul><li>Reflects patient’s volume status </li></ul></ul><ul><ul><li>CVP or PCWP </li></ul></ul><ul><ul><li>Starling curve </li></ul></ul><ul><li>Afterload </li></ul><ul><ul><li>The resistance to ventricular ejection </li></ul></ul><ul><ul><li>Two variables: </li></ul></ul><ul><ul><ul><li>vascular tone and transmural pressure </li></ul></ul></ul><ul><li>Myocardial Contractility (“squeeze”) </li></ul><ul><ul><li>Many factors including coronary perfusion, baseline myocardial function, use of cardiotonic medications </li></ul></ul>
  9. 9. Classification of Shock <ul><ul><li>COMPENSATED </li></ul></ul><ul><ul><ul><li>blood flow is normal or increased and may be maldistributed; vital organ function is maintained </li></ul></ul></ul><ul><ul><li>UNCOMPENSATED </li></ul></ul><ul><ul><ul><li>microvascular perfusion is compromised; significant reductions in effective circulating volume </li></ul></ul></ul><ul><ul><li>IRREVERSIBLE </li></ul></ul><ul><ul><ul><li>inadequate perfusion of vital organs; irreparable damage; death cannot be prevented </li></ul></ul></ul>
  10. 10. Other Classifications <ul><li>Hypovolemic or Hemorrhagic </li></ul><ul><li>Cardiogenic </li></ul><ul><li>Obstructive </li></ul><ul><li>Distributive </li></ul>
  11. 11. Cardiovascular Changes in Shock <ul><li>Type Preload Afterload Contractility </li></ul><ul><li>Cardiogenic    </li></ul><ul><li>Hypovolemic   No change </li></ul><ul><li>Distributive    </li></ul><ul><li>Septic </li></ul><ul><ul><li>early    </li></ul></ul><ul><ul><li>late    </li></ul></ul>
  12. 12. Evaluation <ul><li>Regardless of the cause: ABC’s </li></ul><ul><ul><li>First assess airway patency, ventilation, then circulatory system </li></ul></ul><ul><li>Respiratory Performance </li></ul><ul><ul><li>Respiratory rate and pattern, work of breathing, oxygenation (color), level of alertness </li></ul></ul><ul><li>Circulation </li></ul><ul><ul><li>Heart rate, BP, perfusion, and pulses, liver size </li></ul></ul><ul><ul><li>CVP monitoring may be helpful </li></ul></ul>
  13. 13. Evaluation <ul><li>Early Signs of Shock </li></ul><ul><ul><li>sinus tachycardia </li></ul></ul><ul><ul><li>delayed capillary refill </li></ul></ul><ul><ul><li>fussy, irritable </li></ul></ul><ul><li>Late Signs of Shock </li></ul><ul><ul><li>bradycardia </li></ul></ul><ul><ul><li>altered mental status (lethargy, coma) </li></ul></ul><ul><ul><li>hypotonia, decreased DTR’s </li></ul></ul><ul><ul><li>Cheyne-Stokes breathing </li></ul></ul><ul><ul><li>hypotension is a very late sign </li></ul></ul><ul><ul><li>Lower limit of SBP = 70 + (2 x age in years) </li></ul></ul>
  14. 14. Cardiovascular Assessment <ul><li>Heart Rate </li></ul><ul><ul><li>Too high: 180 bpm for infants, 160 bpm for children >1year old </li></ul></ul><ul><li>Blood Pressure </li></ul><ul><ul><li>Lower limit of SBP = 70 + (2 x age in years) </li></ul></ul><ul><li>Peripheral Pulses </li></ul><ul><ul><li>Present/Absent </li></ul></ul><ul><ul><li>Strength (diminished, normal, bounding) </li></ul></ul><ul><li>Skin Perfusion </li></ul><ul><ul><li>Capillary refill time </li></ul></ul><ul><ul><li>Temperature </li></ul></ul><ul><ul><li>Color </li></ul></ul><ul><ul><li>Mottling </li></ul></ul><ul><li>CNS Perfusion </li></ul><ul><ul><li>Recognition of parents </li></ul></ul><ul><ul><li>Reaction to pain </li></ul></ul><ul><ul><li>Muscle tone </li></ul></ul><ul><ul><li>Pupil size </li></ul></ul><ul><li>Renal Perfusion </li></ul><ul><ul><li>UOP >1cc/kg/hr </li></ul></ul>
  15. 15. Treatment <ul><li>Airway management </li></ul><ul><ul><li>Always provide supplemental oxygen </li></ul></ul><ul><ul><li>Endotracheal intubation and controlled ventilation is suggested if respiratory failure or airway compromise is likely </li></ul></ul><ul><ul><ul><li>elective is safer and less difficult </li></ul></ul></ul><ul><ul><ul><li>decrease negative intrathoracic pressure </li></ul></ul></ul><ul><ul><ul><li>improved oxygenation and O 2 delivery and decreased O 2 consumption </li></ul></ul></ul><ul><ul><ul><li>can hyperventilate if necessary </li></ul></ul></ul>
  16. 16. Treatment <ul><li>Circulation </li></ul><ul><ul><li>Based on presumed etiology </li></ul></ul><ul><ul><li>Rapid restoration of intravascular volume </li></ul></ul><ul><ul><ul><li>PIV-if unstable you have 60-90 seconds </li></ul></ul></ul><ul><ul><ul><li>I.O. if less than 4-6 years old </li></ul></ul></ul><ul><ul><ul><li>Central venous catheter </li></ul></ul></ul><ul><ul><ul><li>Use isotonic fluid: NS, LR, or 5% albumin </li></ul></ul></ul><ul><ul><ul><li>PRBC’s to replace blood loss or if still unstable after 60cc/kg of crystalloid </li></ul></ul></ul><ul><ul><ul><ul><li>anemia is poorly tolerated in the stressed, hypoxic, hemodynamically unstable patient </li></ul></ul></ul></ul>
  17. 17. Vasoactive/Cardiotonic Agents <ul><li>Dopamine </li></ul><ul><ul><li>1-5 mcg/kg/min: dopaminergic </li></ul></ul><ul><ul><li>5-15 mcg/kg/min: more beta-1 </li></ul></ul><ul><ul><li>10-20 mcg/kg/min: more alpha-1 </li></ul></ul><ul><ul><li>may be useful in distributive shock </li></ul></ul><ul><li>Dobutamine </li></ul><ul><ul><li>2.5-15 mcg/kg/min: mostly beta-1, some beta-2 </li></ul></ul><ul><ul><li>may be useful in cardiogenic shock </li></ul></ul><ul><li>Epinephrine </li></ul><ul><ul><li>0.05-0.1 mcg/kg/min: mostly beta-1, some beta-2 </li></ul></ul><ul><ul><li>> 0.1 to 0.2 mcg/kg/min: alpha-1 </li></ul></ul>
  18. 18. Vasoactive/Cardiotonic Agents <ul><li>Norepinephrine </li></ul><ul><ul><li>0.05-0.2mcg/kg/min: only alpha and beta-1 </li></ul></ul><ul><ul><li>Use up to 1mcg/kg/min </li></ul></ul><ul><li>Milrinone </li></ul><ul><ul><li>50mcg/kg load then 0.375-0.75mcg/kg/min: phosphodiesterase inhibitor; results in increased inotropy and peripheral vasodilation (greater effect on pulmonary vasculature) </li></ul></ul><ul><li>Phenylephrine </li></ul><ul><ul><li>0.1-0.5mcg/kg/min: pure alpha </li></ul></ul>
  19. 19. Hypovolemic <ul><li># 1 cause of death in children worldwide </li></ul><ul><li>Causes </li></ul><ul><ul><ul><li>Water Loss (diarrhea, vomiting with poor PO intake, diabetes, major burns) </li></ul></ul></ul><ul><ul><ul><li>Blood Loss (obvious trauma; occult bleeding from pelvic fractures, blunt abdominal trauma, “shaken baby”) </li></ul></ul></ul><ul><li>Low preload leads to decreased SV and decreased CO. </li></ul><ul><li>Compensation occurs with increased HR and SVR </li></ul>
  20. 20. Hypovolemic Shock <ul><li>Mainstay of therapy is fluid </li></ul><ul><li>Goals </li></ul><ul><ul><li>Restore intravascular volume </li></ul></ul><ul><ul><li>Correct metabolic acidosis </li></ul></ul><ul><ul><li>Treat the cause </li></ul></ul><ul><li>Degree of dehydration often underestimated </li></ul><ul><ul><li>Reassess perfusion, urine output, vital signs... </li></ul></ul><ul><li>Isotonic crystalloid is always a good choice </li></ul><ul><ul><li>20 to 50 cc/kg rapidly if cardiac function is normal </li></ul></ul><ul><ul><li>NS can cause a hyperchloremic acidosis </li></ul></ul>
  21. 21. Treatment <ul><li>Solution Na+ Cl- K+ Ca++ Mg++ Buffer </li></ul><ul><li>NS 154 154 0 0 0 None </li></ul><ul><li>LR 130 109 4 3 0 Lactate </li></ul><ul><li>Plasmalyte 140 98 5 0 3 Acetate & Gluconate </li></ul><ul><li>Inotropic and vasoactive drugs are not a substitute for fluid, however... </li></ul><ul><ul><li>Can have various combinations of hypovolemic and septic and cardiogenic shock </li></ul></ul><ul><ul><li>May need to treat poor vascular tone and/or poor cardiac function </li></ul></ul>
  22. 22. Hemorrhagic Shock <ul><li>Treatment is PRBCs or whole blood </li></ul><ul><ul><li>Treat the cause if able (stop the bleeding) </li></ul></ul><ul><ul><li>Transfuse if significant blood loss is known or if patient unstable after 60cc/kg crystalloid </li></ul></ul><ul><ul><ul><li>In an emergency can give group O PRBCs before cross matching is complete or type specific non-cross-matched blood products </li></ul></ul></ul>
  23. 23. Cardiogenic <ul><li>Low CO and high systemic vascular resistance </li></ul><ul><li>Result of primary cardiac dysfunction: </li></ul><ul><ul><ul><li>A compensatory increase in SVR occurs to maintain vital organ function </li></ul></ul></ul><ul><ul><ul><li>Subsequent increase in LV afterload, LV work, and cardiac oxygen consumption </li></ul></ul></ul><ul><ul><ul><li>CO decreases and ultimately results in volume retention, pulmonary edema, and RV failure </li></ul></ul></ul>
  24. 24. Cardiogenic Shock Etiologies <ul><li>Congenital heart disease </li></ul><ul><li>Arrhythmias </li></ul><ul><li>Ischemic heart disease </li></ul><ul><li>Myocarditis </li></ul><ul><li>Myocardial injury </li></ul><ul><li>Acute and chronic drug toxicity </li></ul><ul><li>Late septic shock </li></ul><ul><li>Infiltrative diseases </li></ul><ul><ul><li>mucopolysaccharidoses </li></ul></ul><ul><ul><li>glycogen storage diseases </li></ul></ul><ul><li>Thyrotoxicosis </li></ul><ul><li>Pheochromocytoma </li></ul>
  25. 25. Cardiogenic Shock <ul><li>Initial clinical presentation can be identical to hypovolemic shock </li></ul><ul><li>Initial therapy is a fluid challenge </li></ul><ul><li>If no improvement or if worsens after giving volume, suspect cardiogenic shock </li></ul><ul><li>Usually need invasive monitoring, further evaluation, pharmacologic therapy </li></ul><ul><li>Balancing fluid therapy and inotropic support can be very difficult. </li></ul><ul><ul><li>Call an intensivist and/or a cardiologist </li></ul></ul>
  26. 26. Obstructive Shock <ul><li>Low CO secondary to a physical obstruction to flow </li></ul><ul><li>Compensatory increased SVR </li></ul><ul><li>Causes: </li></ul><ul><ul><li>Pericardial tamponade </li></ul></ul><ul><ul><li>Tension pneumothorax </li></ul></ul><ul><ul><li>Critical coarctation of the aorta </li></ul></ul><ul><ul><li>Aortic stenosis </li></ul></ul><ul><ul><li>Hypoplastic left heart syndrome </li></ul></ul>
  27. 27. Obstructive Shock <ul><li>Initial clinical presentation can be identical to hypovolemic shock </li></ul><ul><li>Initial therapy is a fluid challenge </li></ul><ul><li>Treat the cause </li></ul><ul><ul><li>pericardial drain, chest tube, surgical intervention </li></ul></ul><ul><ul><li>if the patient is a neonate with a ductal dependent lesion then give PGE </li></ul></ul><ul><li>Further evaluation, invasive monitoring, pharmacologic therapy, appropriate consults </li></ul>
  28. 28. Distributive Shock <ul><li>High CO and low SVR (opposite of hypovolemic, cardiogenic, and obstructive) </li></ul><ul><li>Maldistribution of blood flow causing inadequate tissue perfusion </li></ul><ul><li>Due to release of endotoxin, vasoactive substances, complement cascade activation, and microcirculation thrombosis </li></ul><ul><li>Early septic shock is the most common form </li></ul>
  29. 29. Distributive Shock <ul><li>Goal is to maintain intravascular volume and minimize increases in interstitial fluid (the primary problem is a decrease in SVR) </li></ul><ul><ul><li>Use crystalloid initially </li></ul></ul><ul><ul><li>Additional fluid therapy should be based on lab studies </li></ul></ul><ul><ul><li>Can give up to 40cc/kg without monitoring CVP </li></ul></ul><ul><ul><li>Vasoactive/Cardiotonic agents often necessary </li></ul></ul><ul><ul><li>Treat the cause (i.e.. antimicrobial therapy) </li></ul></ul>
  30. 30. Distributive Shock Etiologies <ul><li>Anaphylaxis </li></ul><ul><li>Anaphylactoid reactions </li></ul><ul><li>Spinal cord injury/spinal shock </li></ul><ul><li>Head injury </li></ul><ul><li>Early sepsis </li></ul><ul><li>Drug intoxication </li></ul><ul><ul><li>Barbiturates, Phenothiazines, Antihypertensives </li></ul></ul>
  31. 31. Metabolic Issues Acid-Base <ul><li>Metabolic acidosis develops secondary to tissue hypoperfusion </li></ul><ul><li>Profound acidosis depresses myocardial contractility and impairs the effectiveness of catecholamines </li></ul><ul><li>Tx: fluid administration and controlled ventilation </li></ul><ul><li>Buffer administration </li></ul><ul><ul><li>Sodium Bicarbonate 1-2meq/kg or can calculate a 1/2 correction = 0.3 x weight (kg) x base deficit </li></ul></ul><ul><ul><li>hyperosmolarity, hypocalcemia, hypernatremia, left-ward shift of the oxyhemoglobin dissociation curve </li></ul></ul>
  32. 32. Metabolic Issues Electrolytes <ul><li>Electrolytes </li></ul><ul><ul><li>Calcium is important for cardiac function and for the pressor effect of catecholamines </li></ul></ul><ul><ul><li>Hypoglycemia can lead to CNS damage and is needed for proper cardiovascular function </li></ul></ul><ul><ul><li>Check the BUN and creatinine to evaluate renal function </li></ul></ul><ul><ul><li>Hyperkalemia can occur from renal dysfunction and/or acidosis </li></ul></ul>
  33. 33. Metabolic Issues Special Topics <ul><ul><li>Congenital adrenal hyperplasia </li></ul></ul><ul><ul><ul><li>Infant presents in shock, usually in the second week of life, typically a boy, with metabolic acidosis, hyponatremia, hypoglycemia, and hyperkalemia </li></ul></ul></ul><ul><ul><li>Hyperammonemia </li></ul></ul><ul><ul><ul><li>mild elevations are common with shock </li></ul></ul></ul><ul><ul><ul><li>levels > 1000 are consistent with inborn errors of metabolism </li></ul></ul></ul><ul><ul><ul><li>consider Reye Syndrome, toxins, hepatic failure </li></ul></ul></ul>
  34. 34. Other Studies <ul><li>Look for etiology of shock </li></ul><ul><li>Evaluate hemoglobin, hematocrit, and platelet count </li></ul><ul><ul><li>Should be followed as these values may drop after fluid resuscitation </li></ul></ul><ul><li>Shock from any etiology can lead to DIC and end organ damage </li></ul><ul><ul><li>CBC, PT, INR, PTT, Fibrinogen, Factor V, Factor VIII, D-dimer, and/or FDPs </li></ul></ul><ul><ul><li>Check LFT’s, follow CNS and pulmonary status </li></ul></ul>
  35. 35. Other Studies II <ul><li>Think about inborn errors of metabolism </li></ul><ul><ul><li>Lactate and pyruvate </li></ul></ul><ul><ul><li>Ammonium, LFTs </li></ul></ul><ul><ul><li>Plasma amino acids, urine organic acids </li></ul></ul><ul><ul><li>Urinalysis with reducing substances </li></ul></ul><ul><ul><li>Urine tox screen </li></ul></ul>
  36. 36. Conclusion <ul><li>Goal of therapy is identification, evaluation, and treatment of shock in its earliest stage </li></ul><ul><li>Initial priorities are for the ABC’s </li></ul><ul><li>Fluid resuscitation begins with 20cc/kg of crystalloid or 10cc/kg of colloid </li></ul><ul><li>Subsequent treatment depends on the etiology of shock and the patient’s hemodynamic condition </li></ul><ul><li>Successful resuscitation depends on early and judicious intervention </li></ul>

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