Shock Overview and Hypovolemic Shock

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Questions and Answers

What is the primary cause of hypovolemic shock?

Heart failure

Severe allergic reaction

Inadequate blood volume (correct)

Infection leading to sepsis

What is the first step in stopping external bleeding according to the 3 Ps?

Packing of the wound

Resuscitation techniques

Position the bleeding limb elevated (correct)

Pressure applied by bandage

Which metabolic response occurs as a result of hypovolemic shock?

Increased protein synthesis

Decreased glucose metabolism

Enhanced mitochondrial ATP production

Catabolism of proteins (correct)

What is a major disadvantage of using blood for restoration of blood volume?

It requires time for grouping Signup and view all the answers

How does the body respond to low arterial blood pressure (ABP) during hypovolemic shock?

Stimulates the sympathetic nervous system leading to vasoconstriction Signup and view all the answers

Which fluid is primarily used for sodium loss replacement?

Isotonic saline Signup and view all the answers

Which hormone is primarily responsible for vasodilation in response to hypovolemic shock?

Adrenaline Signup and view all the answers

What is a significant risk associated with the use of Vasoactive drugs, specifically vasoconstrictors?

Impairment of tissue perfusion Signup and view all the answers

Which of the following describes a cellular response in hypovolemic shock?

Na+ outflow and K+ inflow Signup and view all the answers

What is the result of renal ischemia during hypovolemic shock?

Stimulation of the renin-angiotensin system Signup and view all the answers

What is the ideal medication to relieve pain and anxiety in emergencies?

Morphine Signup and view all the answers

Which of the following factors does NOT contribute to the physiological response during hypovolemic shock?

Decreased heart rate due to increased parasympathetic activity Signup and view all the answers

What is the main contraindication for using Morphine in treatment?

Head trauma Signup and view all the answers

What type of acidosis is commonly associated with hypovolemic shock?

Lactic acidosis Signup and view all the answers

Which of the following medications is used to improve myocardial contractility?

Dopamine Signup and view all the answers

What is a common effect of Corticosteroids used in emergencies?

Na and water retention Signup and view all the answers

What is the primary cause of septic shock?

Gram-negative septicemia Signup and view all the answers

Which method is a recommended positioning technique to improve blood flow during septic shock?

Elevating the lower limbs about 30 degrees Signup and view all the answers

What is a potential complication of septic shock that can affect the lungs?

Acute respiratory distress syndrome (ARDS) Signup and view all the answers

Which of the following substances is released by macrophages and contributes to the pathology of septic shock?

Cytokines Signup and view all the answers

What is the systolic blood pressure threshold that defines hypotension in septic shock?

Below 90 mmHg Signup and view all the answers

Which factor does NOT predispose a person to septic shock?

Regular exercise Signup and view all the answers

What effect does endotoxin have on the microcirculation during septic shock?

Pooling of blood and capillary paralysis Signup and view all the answers

Which of the following is a surgical cause of septic shock?

Post-operative sepsis in the genitourinary tract Signup and view all the answers

Which treatment is appropriate for a patient with disseminated intravascular coagulation (DIC)?

Vitamin K by slow IV infusion Signup and view all the answers

What common condition may lead to disseminated intravascular coagulation (DIC)?

Septicemia Signup and view all the answers

Which laboratory finding is indicative of thrombocytopenia?

Low platelet count Signup and view all the answers

What is a potential complication of anti-coagulant therapy if not properly adjusted?

Severe bleeding events Signup and view all the answers

What is one of the symptoms that may lead to a suspicion of disseminated intravascular coagulation (DIC)?

Diffuse bleeding from multiple sites Signup and view all the answers

Which medication is known to interfere with platelet function?

Ibuprofen Signup and view all the answers

What parameter is assessed to evaluate hemostasis during a pre-operative evaluation?

History of abnormal bleeding Signup and view all the answers

Which condition is NOT typically associated with thrombocytopenic purpura?

Malignant hyperthermia Signup and view all the answers

What is the normal range for a platelet count?

150,000 - 400,000/ul Signup and view all the answers

Which test is specifically prolonged with platelet and vascular defects?

Bleeding Time Signup and view all the answers

What does a normal Prothrombin Time (PT) typically range from?

11 to 13.5 seconds Signup and view all the answers

Which condition affects both males and females and is usually milder than hemophilia?

Von Willebrand disease Signup and view all the answers

Which abnormality can occur with a platelet count less than 20,000/ul?

Spontaneous bleeding Signup and view all the answers

Which test measures the time of clotting through the intrinsic and common pathways?

Activated Partial Thromboplastin Time Signup and view all the answers

Which of the following conditions requires both parents to pass a mutated gene for its most severe form?

Von Willebrand disease Signup and view all the answers

What is the role of von Willebrand factor (vWF) in hemostasis?

Attaches platelets to blood vessel walls Signup and view all the answers

Study Notes

Shock Overview

Defined as inadequate tissue perfusion leading to impaired cellular metabolism and accumulation of waste products.
Classified into hypovolemic, septic, cardiogenic, neurogenic, anaphylactic, and endocrinal shock.

Hypovolemic Shock

Results from decreased blood volume, which can be due to:
- Blood loss (e.g., hemorrhage).
- Plasma loss (e.g., burns, acute pancreatitis).
- Fluid loss (e.g., severe vomiting and diarrhea).
Neural factors include decreased arterial blood pressure (ABP) and central venous pressure (CVP), leading to sympathetic nervous system activation.
Endocrinal responses involve adrenaline and noradrenaline secretion, which increases heart rate and blood pressure, and promote fluid retention via vasopressin.
Metabolic response includes:
- Protein catabolism and glycogenolysis in the liver.
- Lactic acid production from anaerobic metabolism, causing metabolic acidosis.
Cellular response involves sodium influx and potassium efflux, mitochondrial damage, and lysosomal rupture.

First Aid Measures for Hypovolemic Shock

Stop external bleeding using the three Ps: position, packing, pressure.
Immediate resuscitation approach focusing on Airway, Breathing, Circulation, Disability, and Exposure.

Blood Volume Restoration

Restoration methods include:
- Blood replacement for blood loss.
- Plasma for plasma loss.
- Fluid for dehydration.
Blood is highly effective for blood loss but has risks, such as compatibility testing time and potential complications.
Plasma supplies coagulation factors but is expensive and carries disease transmission risks.
Plasma substitutes like Dextran and Gelatin have limitations including hemodilution and adverse effects.

Crystalloid Solutions

Common formulations include:
- Dextrose 5% (water replacement).
- Isotonic saline (sodium loss replacement).
- Ringer lactate (intestines fluid loss replacement).
Advantages: availability and cost-effectiveness. However, they are quickly lost from the circulation.

Medications for Shock

Sedatives like morphine relieve pain and anxiety but are contraindicated in certain head trauma cases.
Corticosteroids combat stress responses and promote sodium and water retention.
Vasoactive drugs:
- Vasoconstrictors (e.g., adrenaline) can impair tissue perfusion and increase myocardial workload.
- Vasodilators (e.g., di-phenoxy-benzamine) require prior fluid stabilization to improve tissue perfusion.
Inotropic drugs like dopamine and dobutamine strengthen myocardial contractility and enhance renal perfusion.
Antibiotics are crucial to prevent septic complications; intravenous administration is preferred.

Positioning and Temperature Control

Elevate lower limbs to enhance venous return and perfusion to vital organs.
Use blankets for warmth, avoiding artificial heaters to prevent increased oxygen demand.

Septic Shock

Characterized by sepsis plus hypotension (systolic <90 mmHg).
Predisposing factors: extremes of age, diabetes mellitus, malnutrition, malignancy, uremia, and immunosuppressive therapy.
Primarily caused by septicemia, especially from Gram-negative bacteria releasing endotoxins.
Surgical causes include infections post-operation on genitourinary and gastrointestinal tracts, major trauma, and septic peritonitis.

Pathophysiology of Septic Shock

Endotoxins trigger cytokine release, damaging microcirculation and leading to:
- Capillary sphincter paralysis.
- Disseminated intravascular coagulation (DIC).
Affects multiple organ systems, potentially causing ARDS, renal and hepatic failure, and gastrointestinal complications.

Treatment of Septic Shock

Vitamin K administration and factor concentrates in emergencies.
Fresh frozen plasma may be necessary to manage coagulopathy.

Disseminated Intravascular Coagulation (DIC)

Triggered by severe trauma, sepsis, and other medical conditions.
Symptoms include diffuse bleeding, bruising, and purpura.
Diagnosis involves thrombocytopenia, elevated fibrin degradation products, and prolonged clotting times (PT, PTT).

Treatment for DIC

Address underlying conditions and provide supplemental coagulation factors.
Fresh frozen plasma and platelet transfusions are critical for restoring blood volume and oxygen capacity.

Platelet Disorders

Thrombocytopenia can be primary (essential thrombocytopenic purpura) or secondary (due to medications or other conditions).
Platelet function impairment can be induced by drugs, uremia, or hypothermia.

Pre-operative Evaluation of Hemostasis

Essential to gather a thorough history, including:
- Personal, present, past, and family histories of bleeding disorders.
Physical examination identifies signs of liver disease and bleeding tendencies.

Tests of Hemostasis

Primary Hemostasis tests include platelet count, bleeding time, and platelet function assessments.
Secondary Hemostasis tests like PT/INR and aPTT measure clotting pathways and factor deficiencies.

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Description

This quiz covers the key concepts of shock, including its definitions, classifications, and the specifics of hypovolemic shock. It delves into the causes, neural, endocrine, metabolic, and cellular responses involved in this critical condition. Test your understanding of these vital medical concepts.