Presentation on theme: "Chapter 20 Heart Failure and Circulatory Shock"— Presentation transcript:
1 Chapter 20 Heart Failure and Circulatory Shock Essentials of PathophysiologyChapter 20 Heart Failure and Circulatory Shock
2 Pre Lecture Quiz True/False Decreased cardiac output will lead to an increase in renal blood flow and glomerular filtration rate. The endothelins are potent vasodilators that are released from the endothelial cells throughout the circulation. Myocardial hypertrophy is a long-term mechanism by which the heart compensates for increased workload. Afterload represents the force that the contracting heart must generate to eject blood from the filled heart. Five major complications of severe shock are acute respiratory distress syndrome, acute renal failure, gastrointestinal ulceration, disseminated intravascular coagulation, and multiple organ dysfunction syndrome.FFTTT
3 Pre lecture quizIn __________ heart failure, blood backs up in the systemic circulation, causing peripheral edema and congestion of the abdominal organs. The most common cause of ____________ shock is myocardial infarction.Examples of conditions that cause __________ shock include loss of whole blood (e.g., hemorrhage), plasma loss (e.g., severe burns), or extracellular fluid (e.g., gastrointestinal fluids lost in vomiting or diarrhea).An increase in __________ rate is an early sign of shock.A life-threatening condition, acute __________ edema is the most dramatic symptom of left heart failure and is characterized by capillary fluid moving into the alveoli.cardiogenicheart hypovolemicpulmonaryright
4 Standard ECG waveform Ventricular Contraction initiated Ventricular RelaxationAtrial Contraction initiatedPapillary Muscle RelaxationST segment can indicate ischemia or infarction
5 ST segment elevation ST Depression With a 12 lead ECG certain leads can be connected to each other to reverse the R wave and accentuate the ST Elevation
6 CORORNARY OCCLUSIONtotal occlusion of the proximal segment of left anterior descending artery, andsevere disease involving the proximal segment of the obtuse marginal branchAngiogram
7 High-output versus low-output failure Systolic or diastolic failure Types of Heart FailureHigh-output versus low-output failureIs cardiac output high or low?Systolic or diastolic failureIs the heart failing to pump out enough blood, or failing to accept enough blood from the body and lungs?Right-sided or left-sided failureIs the right or left side of the heart failing?
8 Manifestations of Heart Failure Effects of impaired pumpingEffects of decreased renal blood flow RAA pathwayEffects of the sympathetic nervous systemAngioplasty CABG
9 Manifestations of Heart Failure Orthopnea: Straight Breathing, ie. Must be straight upright, or difficult breathing occursAuthor: Please add title.
10 Control of Heart function Author: Please add title.
11 Scenario:Mr. M has heart failure and he complains of severe shortness of breath, and has fluid in his lungs. He has tachycardia, increased diastolic blood pressure, pale moist skin, and says he feels weak, dizzy, and anxious all the time.Question:Which of these signs and symptoms are due to decreased renal blood flow?Which are due to the sympathetic nervous system?Which side of his heart do you think is failing?
12 Left-Sided Heart Failure Blood FlowbodySystolic: LV does not pump enough blood to bodyBody lacks bloodrightleftheartheartLungs fill with fluidDiastolic: LV does not accept enough blood from lungslungs
13 Right-Sided Heart Failure Blood FlowDiastolic: RV does not accept enough blood from bodybodyBody fills with bloodrightleftheartheartLungs do not oxygenate enough bloodSystolic: RV does not pump enough blood to lungslungs
14 Pulmonary Edema Capillary fluid moves into alveoli Lung becomes stifferHarder to inhaleLess gas exchange in alveoliCracklesFrothy pink sputumHemoglobin not completely oxygenated
15 QuestionTell whether the following statement is true or false: The characteristic pink sputum produced is pulmonary edema is tinged with blood.
16 AnswerTrue In pulmonary edema, the alveolar capillary membrane is damaged, and blood from the capillaries moves into the alveoli. The blood from the capillaries causes the sputum (produced from the lower respiratory tract) to appear pink or light red.
17 Heart fails to pump blood adequately Cardiogenic ShockHeart fails to pump blood adequatelyDecreased cardiac output lowers BPSympathetic system respondsVasoconstriction increases resistance to blood flowIncreased workload on heart worsens heart failure
18 Types of ShockCardiogenicHypovolemicObstructiveDistributiveSeptic
19 BP = CO x PR Blood Pressure Which of the following affect CO, and which affect PR? Why?Blood volumeHeart rateVasoconstrictionAngiotensin IIAldosteroneEpinephrineHistamine
20 Scenario: Mr. M was injured in a motorcycle accident. On his arrival at the hospital he presented with bleeding from the right leg, restlessness, pallor, sweating, elevated heart rate, weak pulse, rapid breathing, and lack of bowel sounds; his blood pressure was slightly elevatedQuestion:What has happened to this patient’s:Stroke volumeCardiac outputSympathetic nervous system
21 Scenario (cont.)Although he was given 6 units of blood, Mr. M got worseHe became lethargic and his blood pressure began to fall; he still had no bowel sounds or urine productionQuestion:The intern ordered epinephrine, and Mr. M’s blood pressure increased. Why?Later, you overhear the resident telling the intern that was not the best treatment. Why not, if it raised Mr. M’s blood pressure?
22 Scenario (cont.)Mr. M’s blood pressure went up a bitHe has been moved out of the ICUQuestion:His chart says you should do a 24-hour urine collection. Why?
23 Scenario (cont.) Mr. M appears to be improving He sleeps quite a lot, but his blood pressure has remained stable; he had a little urine production; and he did not eat his supperChecking on him in the evening, you notice that he is slightly flushed, his respiration rate is a little high, and his temperature is elevatedQuestion:What is happening to his peripheral resistance?What do you expect his heart rate to be like? Why?
24 Distributive or Vasodilatory Shock Blood vessels dilateThere is not enough blood to fill the circulatory systemBlood flow decreasesLess blood is returned to the heartLess blood is circulated to the body
25 QuestionWhich type of shock is caused by low blood volume?CardiogenicHypovolemicDistributiveSeptic
26 AnswerHypovolemicHypo (low) volemia (blood volume) occurs when a patient has lost blood due to trauma, surgery, or third space fluid loss.
27 Causes of Distributive Shock Decreased sympathetic activity: neurogenicBrain or spine injury; anesthetics; insulin shock; emotionVasodilator substances in bloodType I hypersensitivity (anaphylactic shock)Inflammatory response to infection (sepsis)Vessel damage from severe hypovolemia
28 Mechanism of Type I Hypersensitivity Mast cellAllergenMechanism of Type I HypersensitivityGranules released: Histamine, acetylcholine, kinins, leukotrienes, and prostaglandins all cause vasodilationIgE attaches to mast cellAllergenattachesto IgEMast cell degranulates
29 AnaphylaxisSystemic response to the inflammatory mediators released in type I hypersensitivityHistamine, acetylcholine, kinins, leukotrienes, and prostaglandins all cause vasodilationWhat will happen when arterioles vasodilate throughout the body?Acetylcholine, kinins, leukotrienes, and prostaglandins all can cause bronchoconstrictionWhat will happen when the bronchioles constrict?
30 Sepsis or Systemic Inflammatory Response Syndrome (SIRS) Inflammatory mediators released into the circulationTumor necrosis factorInterleukinsProstaglandinsCause systemic signs of inflammationFever and increased respiration, respiratory alkalosis, vasodilation, warm flushed skinActivate inflammatory pathwaysCoagulation, complement
31 Sepsis or Systemic Inflammatory Response Syndrome (SIRS) (cont.) Discussion:Why is septic shock called distributive?In the later phases of septic shock, blood volume decreases. What part of the inflammatory process explains this?
35 The role of the endothelium in severe sepsis and multiple organ dysfunction syndrome Septic ShockAlso called systemic inflammatory response syndrome (SIRS)Inflammatory mediators also increase the metabolic rate of tissues, so they need more oxygen
36 The role of the endothelium in severe sepsis and multiple organ dysfunction syndrome inflammatorymediatorsvascular endothelial cellsrespond and:promotecreateproduce moreclotadhesivevasodilationformationmoleculessubstances (NO)more WBCs move out intomorethe tissues and release morevasodilationinflammatory mediators(Aird, W. C. [2003.] The role of the endothelium in severe sepsis and multiple organ dysfunction syndrome. Blood 101, Retrieved February 10, 2004, from journal.org/cgi/content/full/101/10/3765.0)
37 Septic Shock (cont.)“Despite the prompt implementation of appropriate antibiotic therapy, sepsis mortality remains high, in the range of 28% to 50%.”“Second, patients with culture-positive and culture-negative sepsis or septic shock have comparable mortality rates.”(Aird, W. C. [2003.] The role of the endothelium in severe sepsis and multiple organ dysfunction syndrome. Blood 101, Retrieved February 10, 2004, from journal.org/cgi/content/full/101/10/3765.0)
38 Septic Shock (cont.)“Third, administration of anti-endotoxin antibodies in large, clinical trials did not improve survival.”(Aird, W. C. [2003.] The role of the endothelium in severe sepsis and multiple organ dysfunction syndrome. Blood 101, Retrieved February 10, 2004, from journal.org/cgi/content/full/101/10/3765.0)
39 QuestionWhich type of shock is the result of a severe allergic reaction?CardiogenicObstructiveAnaphylacticSeptic
40 AnswerAnaphylacticAnaphylactic shock is caused when inflammatory mediators are released (type I hypersensitivity reaction). The mediators include histamine, acetylcholine, kinins, leukotrienes, and prostaglandins, all of which cause vasodilation.
41 The main function of protein C is its anticoagulant property as an inhibitor of coagulation factors V and VIIIActivated Protein CDrotrecogin alpha - a recombinant form of human activated protein C that has anti-thrombotic, anti- inflammatory, and profibrinolytic properties - a treatment for severe sepsisBlocks clottingBlocks inflammationIncreases survival of the most seriously ill sepsis patientsMay cause bleeding!
42 Complications of Shock Scenario:A doctor has been called in to treat Mr. M and has started him on fluid and antibioticsYou are warned to watch him carefully for any signs of respiratory distressQuestion:Why would blood pressure imbalances cause respiratory distress?
43 Complications of Shock (cont.) Acute respiratory distress syndromeAcute renal failureGastrointestinal complicationsDisseminated intravascular coagulationMultiple organ dysfunction syndrome
44 Acute Respiratory Distress Syndrome (ARDS) Exudate enters alveoliBlocks gas exchangeMakes inhaling more difficultNeutrophils enter alveoliRelease inflammatory mediatorsRelease proteolytic enzymes
47 Multiple Organ Dysfunction Syndrome (MODS) The most frequent cause of death in the noncoronary intensive care unitMortality rates vary from 30% to 100%Mechanism not known
48 QuestionTell whether the following statement is true or false: Treatment for ARDS often includes breathing assistance using mechanical ventilation.
49 AnswerTrue Because alveoli are filled with exudate and blood that has leaked from the capillary, the surface area available for gas exchange is greatly reduced. Most patients will require ventilatory support until the process reverses. ARDS has a high mortality rate because it is difficult to ventilate these patients.