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UTHSCSA Pediatric Resident Curriculum for the PICU SHOCK IN CHILDREN.

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Presentation on theme: "UTHSCSA Pediatric Resident Curriculum for the PICU SHOCK IN CHILDREN."— Presentation transcript:

1 UTHSCSA Pediatric Resident Curriculum for the PICU SHOCK IN CHILDREN

2 UTHSCSA Pediatric Resident Curriculum for the PICU Definition Circulatory system failure to supply oxygen and nutrients to meet cellular metabolic demands

3 UTHSCSA Pediatric Resident Curriculum for the PICU Other Definitions Blood Pressure Blood Pressure BP = CO x SVR Cardiac Output Cardiac Output CO = SV X HR Vascular Tone (SVR) Vascular Tone (SVR) – Regulated by several mechanisms

4 UTHSCSA Pediatric Resident Curriculum for the PICU Oxygen Delivery DO 2 = CO x CaO 2 x 10 DO 2 = CO x CaO 2 x 10 – Remember: CO depends on HR, preload, afterload, and contractility CaO 2 = Hgb x 1.34 x SaO 2 + (PaO 2 x 0.003) CaO 2 = Hgb x 1.34 x SaO 2 + (PaO 2 x 0.003) – Remember: hemoglobin carries more than 99% of oxygen in the blood under standard conditions

5 UTHSCSA Pediatric Resident Curriculum for the PICU Hemodynamics Textbook of Pediatric Advanced Life Support, 1988

6 UTHSCSA Pediatric Resident Curriculum for the PICU Defending the blood pressure Neural Sympathetic Neural Sympathetic – Baroreceptors Carotid Body Carotid Body Aortic Arch Aortic Arch – Volume receptors Right Atrium Right Atrium Pulmonary vascular Pulmonary vascular – Chemoreceptors Aortic and carotid Aortic and carotid Medullary Medullary – Cerebral ischemic response Humoral – Adrenal medulla Catecholamines – Hypothalamopituitary response Adrenocorticotropic hormone Vasopressin – Renin-angiotensin- aldosterone system

7 UTHSCSA Pediatric Resident Curriculum for the PICU Cardiovascular function Cardiac Output Cardiac Output  Clinical Assessment peripheral perfusion, temperature, capillary refill, urine output, mentation, acid-base status peripheral perfusion, temperature, capillary refill, urine output, mentation, acid-base status  CO = HR x SV HR responds the quickest HR responds the quickest SV is a function of three variables SV is a function of three variables – preload, afterload, and myocardial contractility A noncompliant heart cannot increase SV A noncompliant heart cannot increase SV

8 UTHSCSA Pediatric Resident Curriculum for the PICU Stroke Volume Preload (LVEDV) Preload (LVEDV) – Reflects patient’s volume status – CVP or PCWP – Starling curve Afterload Afterload – The resistance to ventricular ejection – Two variables: vascular tone and transmural pressure vascular tone and transmural pressure Myocardial Contractility (“squeeze”) Myocardial Contractility (“squeeze”) – Many factors including coronary perfusion, baseline myocardial function, use of cardiotonic medications

9 UTHSCSA Pediatric Resident Curriculum for the PICU Classification of Shock COMPENSATED COMPENSATED – blood flow is normal or increased and may be maldistributed; vital organ function is maintained UNCOMPENSATED UNCOMPENSATED – microvascular perfusion is compromised; significant reductions in effective circulating volume IRREVERSIBLE IRREVERSIBLE – inadequate perfusion of vital organs; irreparable damage; death cannot be prevented

10 UTHSCSA Pediatric Resident Curriculum for the PICU Other Classifications Hypovolemic or Hemorrhagic Hypovolemic or Hemorrhagic Cardiogenic Cardiogenic Obstructive Obstructive Distributive Distributive

11 UTHSCSA Pediatric Resident Curriculum for the PICU Cardiovascular Changes in Shock Type Preload Afterload Contractility Cardiogenic    Hypovolemic   No change Distributive    Septic early    late   

12 UTHSCSA Pediatric Resident Curriculum for the PICU Evaluation Regardless of the cause: ABC’s Regardless of the cause: ABC’s – First assess airway patency, ventilation, then circulatory system Respiratory Performance Respiratory Performance – Respiratory rate and pattern, work of breathing, oxygenation (color), level of alertness Circulation Circulation – Heart rate, BP, perfusion, and pulses, liver size – CVP monitoring may be helpful

13 UTHSCSA Pediatric Resident Curriculum for the PICU Evaluation Early Signs of Shock Early Signs of Shock – sinus tachycardia – delayed capillary refill – fussy, irritable Late Signs of Shock Late Signs of Shock – bradycardia – altered mental status (lethargy, coma) – hypotonia, decreased DTR’s – Cheyne-Stokes breathing – hypotension is a very late sign – Lower limit of SBP = 70 + (2 x age in years)

14 UTHSCSA Pediatric Resident Curriculum for the PICU Cardiovascular Assessment Heart Rate Heart Rate – Too high: 180 bpm for infants, 160 bpm for children >1year old Blood Pressure Blood Pressure – Lower limit of SBP = 70 + (2 x age in years) Peripheral Pulses Peripheral Pulses – Present/Absent – Strength (diminished, normal, bounding) Skin Perfusion – Capillary refill time – Temperature – Color – Mottling CNS Perfusion – Recognition of parents – Reaction to pain – Muscle tone – Pupil size Renal Perfusion – UOP >1cc/kg/hr

15 UTHSCSA Pediatric Resident Curriculum for the PICU Treatment Airway management – Always provide supplemental oxygen – Endotracheal intubation and controlled ventilation is suggested if respiratory failure or airway compromise is likely elective is safer and less difficult elective is safer and less difficult decrease negative intrathoracic pressure decrease negative intrathoracic pressure improved oxygenation and O 2 delivery and decreased O 2 consumption improved oxygenation and O 2 delivery and decreased O 2 consumption can hyperventilate if necessary can hyperventilate if necessary

16 UTHSCSA Pediatric Resident Curriculum for the PICU Treatment Circulation – Based on presumed etiology – Rapid restoration of intravascular volume PIV-if unstable you have seconds PIV-if unstable you have seconds I.O. if less than 4-6 years old I.O. if less than 4-6 years old Central venous catheter Central venous catheter Use isotonic fluid: NS, LR, or 5% albumin Use isotonic fluid: NS, LR, or 5% albumin PRBC’s to replace blood loss or if still unstable after 60cc/kg of crystalloid PRBC’s to replace blood loss or if still unstable after 60cc/kg of crystalloid – anemia is poorly tolerated in the stressed, hypoxic, hemodynamically unstable patient

17 UTHSCSA Pediatric Resident Curriculum for the PICU Vasoactive/Cardiotonic Agents Dopamine Dopamine – 1-5 mcg/kg/min: dopaminergic – 5-15 mcg/kg/min: more beta-1 – mcg/kg/min: more alpha-1 – may be useful in distributive shock Dobutamine Dobutamine – mcg/kg/min: mostly beta-1, some beta-2 – may be useful in cardiogenic shock Epinephrine Epinephrine – mcg/kg/min: mostly beta-1, some beta-2 – > 0.1 to 0.2 mcg/kg/min: alpha-1

18 UTHSCSA Pediatric Resident Curriculum for the PICU Vasoactive/Cardiotonic Agents Norepinephrine Norepinephrine – mcg/kg/min: only alpha and beta-1 – Use up to 1mcg/kg/min Milrinone Milrinone – 50mcg/kg load then mcg/kg/min: phosphodiesterase inhibitor; results in increased inotropy and peripheral vasodilation (greater effect on pulmonary vasculature) Phenylephrine Phenylephrine – mcg/kg/min: pure alpha

19 UTHSCSA Pediatric Resident Curriculum for the PICU Hypovolemic # 1 cause of death in children worldwide # 1 cause of death in children worldwide Causes Causes Water Loss (diarrhea, vomiting with poor PO intake, diabetes, major burns) Water Loss (diarrhea, vomiting with poor PO intake, diabetes, major burns) Blood Loss (obvious trauma; occult bleeding from pelvic fractures, blunt abdominal trauma, “shaken baby”) Blood Loss (obvious trauma; occult bleeding from pelvic fractures, blunt abdominal trauma, “shaken baby”) Low preload leads to decreased SV and decreased CO. Low preload leads to decreased SV and decreased CO. Compensation occurs with increased HR and SVR Compensation occurs with increased HR and SVR

20 UTHSCSA Pediatric Resident Curriculum for the PICU Hypovolemic Shock Mainstay of therapy is fluid Mainstay of therapy is fluid Goals Goals – Restore intravascular volume – Correct metabolic acidosis – Treat the cause Degree of dehydration often underestimated Degree of dehydration often underestimated – Reassess perfusion, urine output, vital signs... Isotonic crystalloid is always a good choice Isotonic crystalloid is always a good choice – 20 to 50 cc/kg rapidly if cardiac function is normal – NS can cause a hyperchloremic acidosis

21 UTHSCSA Pediatric Resident Curriculum for the PICU Treatment Solution Na+ Cl- K+ Ca++ Mg++ Buffer NS None LR Lactate Plasmalyte Acetate & Gluconate  Inotropic and vasoactive drugs are not a substitute for fluid, however... – Can have various combinations of hypovolemic and septic and cardiogenic shock – May need to treat poor vascular tone and/or poor cardiac function

22 UTHSCSA Pediatric Resident Curriculum for the PICU Hemorrhagic Shock Treatment is PRBCs or whole blood Treatment is PRBCs or whole blood – Treat the cause if able (stop the bleeding) – Transfuse if significant blood loss is known or if patient unstable after 60cc/kg crystalloid In an emergency can give group O PRBCs before cross matching is complete or type specific non-cross-matched blood products In an emergency can give group O PRBCs before cross matching is complete or type specific non-cross-matched blood products

23 UTHSCSA Pediatric Resident Curriculum for the PICU Cardiogenic Low CO and high systemic vascular resistance Low CO and high systemic vascular resistance Result of primary cardiac dysfunction: Result of primary cardiac dysfunction:  A compensatory increase in SVR occurs to maintain vital organ function  Subsequent increase in LV afterload, LV work, and cardiac oxygen consumption  CO decreases and ultimately results in volume retention, pulmonary edema, and RV failure

24 UTHSCSA Pediatric Resident Curriculum for the PICU Cardiogenic Shock Etiologies Congenital heart disease Congenital heart disease Arrhythmias Arrhythmias Ischemic heart disease Ischemic heart disease Myocarditis Myocarditis Myocardial injury Myocardial injury Acute and chronic drug toxicity Acute and chronic drug toxicity Late septic shock Infiltrative diseases – mucopolysaccharidoses – glycogen storage diseases Thyrotoxicosis Pheochromocytoma

25 UTHSCSA Pediatric Resident Curriculum for the PICU Cardiogenic Shock Initial clinical presentation can be identical to hypovolemic shock Initial clinical presentation can be identical to hypovolemic shock Initial therapy is a fluid challenge Initial therapy is a fluid challenge If no improvement or if worsens after giving volume, suspect cardiogenic shock If no improvement or if worsens after giving volume, suspect cardiogenic shock Usually need invasive monitoring, further evaluation, pharmacologic therapy Usually need invasive monitoring, further evaluation, pharmacologic therapy Balancing fluid therapy and inotropic support can be very difficult. Balancing fluid therapy and inotropic support can be very difficult. – Call an intensivist and/or a cardiologist

26 UTHSCSA Pediatric Resident Curriculum for the PICU Obstructive Shock Low CO secondary to a physical obstruction to flow Low CO secondary to a physical obstruction to flow Compensatory increased SVR Compensatory increased SVR Causes: Causes: – Pericardial tamponade – Tension pneumothorax – Critical coarctation of the aorta – Aortic stenosis – Hypoplastic left heart syndrome

27 UTHSCSA Pediatric Resident Curriculum for the PICU Obstructive Shock Initial clinical presentation can be identical to hypovolemic shock Initial clinical presentation can be identical to hypovolemic shock Initial therapy is a fluid challenge Initial therapy is a fluid challenge Treat the cause Treat the cause – pericardial drain, chest tube, surgical intervention – if the patient is a neonate with a ductal dependent lesion then give PGE Further evaluation, invasive monitoring, pharmacologic therapy, appropriate consults Further evaluation, invasive monitoring, pharmacologic therapy, appropriate consults

28 UTHSCSA Pediatric Resident Curriculum for the PICU Distributive Shock High CO and low SVR (opposite of hypovolemic, cardiogenic, and obstructive) High CO and low SVR (opposite of hypovolemic, cardiogenic, and obstructive) Maldistribution of blood flow causing inadequate tissue perfusion Maldistribution of blood flow causing inadequate tissue perfusion Due to release of endotoxin, vasoactive substances, complement cascade activation, and microcirculation thrombosis Due to release of endotoxin, vasoactive substances, complement cascade activation, and microcirculation thrombosis Early septic shock is the most common form Early septic shock is the most common form

29 UTHSCSA Pediatric Resident Curriculum for the PICU Distributive Shock Goal is to maintain intravascular volume and minimize increases in interstitial fluid (the primary problem is a decrease in SVR) Goal is to maintain intravascular volume and minimize increases in interstitial fluid (the primary problem is a decrease in SVR) – Use crystalloid initially – Additional fluid therapy should be based on lab studies – Can give up to 40cc/kg without monitoring CVP – Vasoactive/Cardiotonic agents often necessary – Treat the cause (i.e.. antimicrobial therapy)

30 UTHSCSA Pediatric Resident Curriculum for the PICU Distributive Shock Etiologies Anaphylaxis Anaphylaxis Anaphylactoid reactions Anaphylactoid reactions Spinal cord injury/spinal shock Spinal cord injury/spinal shock Head injury Head injury Early sepsis Early sepsis Drug intoxication Drug intoxication – Barbiturates, Phenothiazines, Antihypertensives

31 UTHSCSA Pediatric Resident Curriculum for the PICU Metabolic Issues Acid-Base Metabolic acidosis develops secondary to tissue hypoperfusion Metabolic acidosis develops secondary to tissue hypoperfusion Profound acidosis depresses myocardial contractility and impairs the effectiveness of catecholamines Profound acidosis depresses myocardial contractility and impairs the effectiveness of catecholamines Tx: fluid administration and controlled ventilation Tx: fluid administration and controlled ventilation Buffer administration Buffer administration – Sodium Bicarbonate 1-2meq/kg or can calculate a 1/2 correction = 0.3 x weight (kg) x base deficit – hyperosmolarity, hypocalcemia, hypernatremia, left-ward shift of the oxyhemoglobin dissociation curve

32 UTHSCSA Pediatric Resident Curriculum for the PICU Metabolic Issues Electrolytes Electrolytes Electrolytes – Calcium is important for cardiac function and for the pressor effect of catecholamines – Hypoglycemia can lead to CNS damage and is needed for proper cardiovascular function – Check the BUN and creatinine to evaluate renal function – Hyperkalemia can occur from renal dysfunction and/or acidosis

33 UTHSCSA Pediatric Resident Curriculum for the PICU Metabolic Issues Special Topics Congenital adrenal hyperplasia Infant presents in shock, usually in the second week of life, typically a boy, with metabolic acidosis, hyponatremia, hypoglycemia, and hyperkalemia Infant presents in shock, usually in the second week of life, typically a boy, with metabolic acidosis, hyponatremia, hypoglycemia, and hyperkalemiaHyperammonemia mild elevations are common with shock mild elevations are common with shock levels > 1000 are consistent with inborn errors of metabolism levels > 1000 are consistent with inborn errors of metabolism consider Reye Syndrome, toxins, hepatic failure consider Reye Syndrome, toxins, hepatic failure

34 UTHSCSA Pediatric Resident Curriculum for the PICU Other Studies Look for etiology of shock Look for etiology of shock Evaluate hemoglobin, hematocrit, and platelet count Evaluate hemoglobin, hematocrit, and platelet count – Should be followed as these values may drop after fluid resuscitation Shock from any etiology can lead to DIC and end organ damage Shock from any etiology can lead to DIC and end organ damage – CBC, PT, INR, PTT, Fibrinogen, Factor V, Factor VIII, D-dimer, and/or FDPs – Check LFT’s, follow CNS and pulmonary status

35 UTHSCSA Pediatric Resident Curriculum for the PICU Other Studies II Think about inborn errors of metabolism Think about inborn errors of metabolism – Lactate and pyruvate – Ammonium, LFTs – Plasma amino acids, urine organic acids – Urinalysis with reducing substances – Urine tox screen

36 UTHSCSA Pediatric Resident Curriculum for the PICU Conclusion Goal of therapy is identification, evaluation, and treatment of shock in its earliest stage Goal of therapy is identification, evaluation, and treatment of shock in its earliest stage Initial priorities are for the ABC’s Initial priorities are for the ABC’s Fluid resuscitation begins with 20cc/kg of crystalloid or 10cc/kg of colloid Fluid resuscitation begins with 20cc/kg of crystalloid or 10cc/kg of colloid Subsequent treatment depends on the etiology of shock and the patient’s hemodynamic condition Subsequent treatment depends on the etiology of shock and the patient’s hemodynamic condition Successful resuscitation depends on early and judicious intervention Successful resuscitation depends on early and judicious intervention


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