Categories & Complications

Transcription

1 Shock, Fluid & Therapy Arthur Jones, EdD, RRT Learning Objectives: Explain the etiologies, manifestations and management of shock. Describe specific agents used to maintain blood pressure, fluid balance and ph, along with their actions, effects and complications. Categories & Complications Shock Definition- inadequate perfusion of tissues to meet metabolic requirements. anaerobic metabolism- lactate release of intracellular substances to system accumulation of metabolic wastes Categories Hypovolemic Distributive Cardiogenic Blood volume loss Hemorrhage Burns Dehydration ƒheat exhaustion ƒdiarrhea, vomiting ƒinadequate intake Copyright 2008 AP Jones 1

2 blood pressure loss due to fluid distribution outside intravascular space or vasodilation. third spacing- water in intersitial space ƒinfusion with crystalloids ƒplasma protein deficit third spacing vasoactive drugs or toxins ==> systemic vasodilation anaphylaxis- allergic response neurogenic vasodilation- loss of sympathetic tone sepsis FYI - Link to article on shock Cardiogenic shock Ineffective cardiac pump myocardial infarction- loss of contractile tissue cardiomyopathy- ventricular dilation, loss of contractility mechanical abnormalities ƒvalvular disease ƒseptal defects- high output failure ƒobstructive defects Complications Acute respiratory distress syndrome (ARDS) Multiple organ system failure cardiac hepatic renal gastrointestinal Complications Hypoxic-ishchemic encephalopathy (HIE) increased intracranial pressure (ICP) when ICP equals mean arterial pressure, cerebral perfusion pressure equals zero. Manifestations FYI - Link to information on HIE Copyright 2008 AP Jones 2

3 General Manifestations Hypotension- PSYS < 90 mm Hg Tachycardia Slow capillary refill CNS signs- vertigo, syncope, coma Pallor Oliguria, anuria Decreased transcutaneous PO2 Specific Manifestations Hemorrhagic low Hb, Hct decreased CVP Dehydration elevated Hb, Hct decreased CVP FYI - Link to article on transcutaneous PO2 and shock Specific Manifestations Anaphylactic history of bite, ingestion pruritus (itching) urticaria (hives) laryngospasm bronchospasm FYI - Link to information on anaphylaxis Specific Manifestations urticaria (hives) Link to picture of hives Link to another picture of hives Specific Manifestations Septic signs of infection- fever, etc. increased cardiac output (QT) decreased C(a-v)DO2 Shock- Specific Manifestations Cardiogenic signs of MI pulmonary edema elevated PCWP (>25 mm Hg) FYI - Link to article on cardiogenic shock Copyright 2008 AP Jones 3

4 Management of Shock Vasopressors contraindicated for hypovolemia because of physiologic vasoconstriction Replacement of the specific fluids lost to circulation is necessary Blood products- hemorrhage whole blood plasma packed red blood cells Colloids- remain in intravascular space temporary for hemorrhage manage third spacing by drawing fluid from interstitium FYI - Link to article on colloids vs. crystalloids in shock Hypovolemic Shock Colloids- remain in intravascular space common fluids ƒhuman albumin- research questions its use ƒdextran large carbohydrate molecule ƒhetastarch (Hespan) Hypovolemic- Fluid Replacement Crystalloids- much loss to interstial (third) space) Primary for dehydration, burns Common fluids ƒnacl- 0.9%, 0.45% ƒdextrose- in water or saline ƒringer's solution ƒringer's lactate- solution of choice for resuscitation Copyright 2008 AP Jones 4

5 Crystalloid solutions Ringer's solution ƒnacl ƒmgcl2 ƒna2hpo4 ƒnahco3 Dehydration, burns Ringer's lactate ƒnacl ƒna lactate ƒkcl ƒcacl Monitoring fluid volume mucosa- wet or dry skin turgor (except for elderly patients) capillary refill Monitoring fluid volume blood pressure CVP PAOP (PCWP) urine output weight Complications of Fluids Blood products Immune reactions; e.g. anaphylaxis Non-immune reactions; e.g.,fluid overload Infections; e.g., HIV FYI - Link to article on transfusion risks Complications of Fluids Blood products Immune reactions; e.g. anaphylaxis Non-immune reactions; e.g.,fluid overload Infections; e.g., HIV Leftward shift in HbO2 curvestored blood transfusion related acute lung FYI - Link injury to article (TRALI) on TRALI Copyright 2008 AP Jones 5

6 Complications of Fluids Crystalloids reduced colloid osmitic pressure (COP) ==> 3rd spacing electrolyte, ph imbalance Dextrose (glucose) hypercapnia, acidemia hyperglycemia Anaphylactic shock Epinephrine vasoconstriction ƒincrease blood pressure ƒreverse mucosal edema bronchodilation Anaphylactic shock Epinephrine Diphenhydramine (Benadryl)- inhibit action of histamine Steroids, e.g., hydrocortisonehelps body cope with stress Beta-agonist; e.g., albuterolbronchospasm Crystalloids Vasopressors epinephrine norepinephrine dopamine vasopressin neosynephrine septic (distributive) shock antibiotics vasopressin (Pitressin) cause by toxins, drugs vasopressors removal of toxin, drug ƒdiuresis ƒdialysis ƒantidotes ƒantitoxins FYI - Link to article on vasopressin in septic shock Copyright 2008 AP Jones 6

7 Cardiogenic shock vasopressors nitrates surgery, angioplasty intra-aortic counterpulsation inotropic agents ƒdobutamine ƒdopamine ƒmilrinone (Primacor) Complications of vasopressors peripheral tissue necrosis renal failure hypertension increased myocardial work Therapy Therapy Purpose- to reverse acid-base imbalance, usually acidemia NaHCO3- action- provides HCO3- ==> [H+l + [HCO3-] ==> H20 + C02 ==> depends on ventilation to excrete C02 Therapy NaHCO3- complications Respiratory acidemia if C02 not excreted Metabolic alkalemia (overdose) Hypernatremia Cerebral edema Therapy NaHCO3- contraindications- ph >7.20 severe hypernatremia, often associated with renal failure Copyright 2008 AP Jones 7

8 Therapy NaHCO3- administration titrated with blood ph HCO3 (meq) = kg * (15 - observed HCO3-) * 0.5 Tris-hydroxymethyl aminomethane- THAM (Tromethamine)- reverses acidemia without excretion of C02 Action- organic proton acceptor THAM Indications ƒmetabolic acidemia with hypernatremia ƒacidemia in conjunction with limitations in ventilationpermissive hypercapnia FYI - Link to article on THAM and permissive hypercapnea THAM Complications ƒapnea ƒhypoglycemia ƒhypokalemia ƒalkalosis ƒtissue necrosis from infiltration THAM Dosage- ml s of THAM of 0.3M solution = body wt in kg X base deficit in MEq/l Tribonat Currently used in Europe Ingredients ƒnahco3 ƒtham ƒacetate ƒpo4 Copyright 2008 AP Jones 8

9 Tribonat- advantages minimal effect on PCO2 minimal overcorrection risk less Na than NaHCO3 no tissue irritability Summary & Review Shock categories hypovolemic distributive cardiogenic Shock- manifestations general category- specific Summary & Review Shock management fluid replacement vasopressors cardiotonics s NaHCO3 THAM Tribonat References Alderson P, et al. Human albumin solution for resuscitation and volume expansion in critically ill patients. Cochrane Database of Systematic Reviews Update Software. Bjerneroth G. Tribonat--a comprehensive summary of its properties. Critical Care Medicine. 27(5): , Kallet RH, et al. The treatment of acidosis in acute lung injury with Tris-hydroxymethyl aminomethane (THAM). Am J Respir Crit Care Med 2000;161: Nau R. Desel H. Lassek C. Kolenda H. Prange H. Entry of tromethamine into the cerebrospinal fluid of humans after cerebrovascular events. Clinical Pharmacology & Therapeutics. 66(1):25-32, END Copyright 2008 AP Jones 9