ECP 3 Flashcards
Define shock and the steps of shock
- Severe haemodynamic and metabolic derangements that lead to an imbalance of oxygen delivery and oxygen consumption, leading to decreased cellular energy production
Progressive cellular dysfunction
-> Progressive organ dysfunction (SIRS and MODS)
-> Failure of compensatory mechanisms
-> Irreversible organ damage
-> Death
What are the 4 types of circulatory shock and the 2 types of non-circulatory shock
Circulatory shock
1. Cardiogenic -> heart isn’t working
2. Hypovolaemia -> not enough volume - MOST COMMON
3. Distributive -> vessels are overly constricted or dilated
4. Obstructive -> something preventing movement
Non-circulatory shock
1. Hypoxic - low haematocrit
2. Metabolic - hypoglycaemia etc.
Hypovolaemic shock what is it, 2 main causes and the 4 main areas that the body responds to this shock
Decreased circulating blood volume Causes - Blood and fluid loss - Decreased intake 1) Sympathetic nervous system 2) renal blood flow 3) Angiotensin II 4) Pituitary gland
Clinical assessment of shock what are the clinical signs for milk, moderate and severe and which shock doesn’t go through this pathway
Mild -> increase pulse and heart rate due to sympathetic drive body responding
Moderate -> heart rate increased, starting to get pale, femoral pulse reduced, metatarsal bearable
Severe -> grey/white, dull, severely decreased pulses
- All go through this pathway except for distributive
Distributive shock what is the definition and list some causes
- DEFINTION: maldistribution of blood flow, inappropriate vasomotor tone (altered SVR) ○ Vasodilation - usually ○ (Vasoconstriction) Causes - Septic shock, SIRS** (systemic inflammatory response syndrome) - Anaphylaxis - Severe acidosis - Adverse drug reaction or drug overdose - Electrolyte derangements - (Pharmacologic vasoconstriction)
Distributive shock what are the main clinical signs in dogs and cats
- Hyperdynamic (early)
○ Hyperaemic mucous membranes
○ Fast CRT
○ Tachycardia, tachypnea (bounding pulses)
○ Normotension or hypertension
○ Tall narrow pulses
Cats are different! - always pale, smaller increases in heart rate
Obstructive shock define and causes
- DEFINITION: obstruction to blood flow CAUSES - GDV - Cardiac tamponade - pericardial effusion - Pulmonary thromboembolism - Aortic thromboembolism - Pulmonary hypertension - Pneumothorax - Neoplasia
Obstructive shock clinical signs
depend on underlying cause
- Distended abdomen (GDV)
- Muffled heart sounds (pericardial eff)
- Dull lung sounds (pneumothorax)
Cardiogenic shock define and what can it be associated with, do you use fluids
- DEFINTITION: decreased FORWARD flow (pump failure)
○ Decrease contractility - systolic or diastolic failure
○ Inappropriate heart rate, arthmia - Can be associated with backward failure (congestive heart failure) -> hypoxia
○ Mitral valve disease may not have forward failure but can have backward failure -> NO CARDIOGENIC - Fluids are generally contraindicated
Cardiogenic shock what are the 3 main causes and causes within
- Systolic failure ○ DCM, Myocardial dysfunction in sepsis, Drug overdose - Diastolic failure ○ Hypertrophic cardiomyopathy - Arrhythmias ○ Tachy-or bradyarrhythmias
Cardiogenic shock what are the 3 main clinical signs groups and signs within
- Similar to hypovolaemicshock AND…
- Signs of cardiac disease and R/L forward failure
○ Murmur / gallop
○ Pulse deficits
○ Poor pulses
○ Tachy-or bradyarrhythmia
○ Distended jugulars
○ Ascites - +/-Respiratory distress - if backward failure is also present
○ Tachypnea
○ Dyspnea
○ Pulmonary crackles
○ Decreased lung sounds
Metabolic shock define and clinical signs
- DEFINITION: deranged cellular metabolic machinery
CLINICAL SIGNS - Dependent upon underlying disease
- Mental depression universal
Metabolic shock causes
- Mitochondrial dysfunction ○ Severe pH derangements ○ Sepsis - in addition to distributive shock and hypovolaemia ○ Cyanide toxicity ○ Bromethalinpoisoning - Hypoadrenocorticism - Hypoglycaemia - Hyperkalaemia - Hypocalcaemia
Hypoxic shock define and causes
- DEFINITION: decreased blood oxygen content
- Mostly related to Haemoglobin levels - haematocrit
○ Haemoglobin concentration times 3 = PCV (haematocrit)
CAUSES - Anemia
- Severe pulmonary parenchymal disease
- Hypoventilation
- Dyshaemoglobinaemias
- Carbon monoxide
Hypoxic shock clinical signs
CLINICAL SIGNS - Dyspnea - Crackles - Increased BV sounds - Mucous membranes ○ Pale, cyanotic, brown
What are the 6 questions in terms of treating shock
Approach to treating shock
- Is it shock?
- If so, what type?
- Is it a type that requires fluid therapy?
- Is there any reason to be especially cautious?
- Is fluid therapy contraindicated?
- Either way, what other therapies will you administer?
How to answer the question is it shock?
Clinical signs - “Flat” might mean shock - Circulatory forms of shock can all look similar - Distributive (septic) looks different - Cats look different - Non-circulatory… depends on underlying cause Other ‘objective’ information - Haemodynamic - Heart rate - MAP < 80 mmHg Tissue perfusion parameters - Lactate > 2.5 mmol/L
How to answer the questions if so what type of shock
- Hypovolaemic –imaging, history, UOP, CVP
- Distributive –CBC, cultures, imaging
- Cardiogenic –ECG, echo
- Obstructive –AXR, CXR imaging, echo
- Metabolic –glucose, calcium, etc
- Hypoxic –SpO2, arterial blood gas (ABG), CXR
How to answer the question is it a type that rewquires fluid therapy
Circulatory - Hypovolaemic–yes! - Distributive –yes! - Obstructive –yes! - Cardiogenic –no! Non-circulatory - Metabolic (often) -> may need to give to rebalance the electrolytes (sodium derangements) - Hypoxic (sometimes)
How to answer the question if shock is there any reason to be cautious
- Heart disease - MAIN - more likely to get fluid overload
Pulmonary disease - MAIN - may make respiratory distress worse
How to answer the questions if shock what other therapies will you administer
- Hypovolaemic ○ Special fluids, blood products - Cardiogenic ○ Inotropes, anti-arrhythmics, diuretics - Distributive ○ Vasopressors, antibiotics - Metabolic ○ Glucocorticoids, dextrose, calcium - Hypoxic ○ Oxygen, ventilation
Acute resuscitative fluid therapy what is important in terms of administration and the types of catheters
- QUICK EXPANSION OF VASCULAR VOLUME
- No subcutaneous administration - NOT FAST ENOUGH
1. Peripheral venous catheter
2. Central venous catheter
3. Intraosseous catheter
Acute resuscitative fluid therapy peripheral venous catheter characteristics
- Most commonly used
- Cephalic or lateral saphenous
- Short and large: less resistance
- Percutaneous vs cut-down
Acute resuscitative fluid therapy central venous catheter characteristics
- External jugular vein
- May be more time consuming
- Long term placement or
- Severely compromised patients
- Cardiopulmonary arrest
- Regular over-the-needle catheter
Acute resuscitative fluid therapy intraoesseous catheter when used
- Routinely in very small patients (kittens and puppies)
- In adult patients where IV access fails
- Cardiopulmonary arrest
List the 4 main resuscitation fluids
- Isotonic crystalloid fluids
- Synthetic colloids
- Hypertonic saline
- Blood products:
○ Whole blood
○ Packed red blood cells
○ Fresh frozen plasma
Hypertonic saline tonicity, 3 indications and what to combine with
- Tonicity»_space; ECF -> fluid from interstitial space to intravascular space
- Indications:
○ Rapid volume expansions
○ Large dogs - GDV
○ Head trauma (may decrease ICP) - Combination with colloids -> water clings to colloid so contain water within vascular - provides prolonged affect
Hypertonic saline what are the effects and contraindications
- Other effects: ○ Decrease intracranial pressure ○ Reduce endothelial swelling ○ Decrease leucocyte adhesion ○ Increase cardiac contractility ○ Milkd peripheral vasodilation - Contraindications ○ Dehydration ○ Normovolaemia/hypercolaemia ○ Hypernatraemia -> adding to the imbalance of sodium ○ Inability to handle sodium load (renal disease)
Synthetic colloids what is the maximum can give for cat and dog, what volume want to give and adverse effects
- Dog: Up to 20ml/kg total/day
- Cat: Up to 10ml/kg total/day
- Small volume resuscitation -> if give large volumes and increase vascular permeability movement of colloid into interstitium and moves water into interstitium resulting in loss of water instead of gain in intravascular system
- Adverse effects
○ Coagulation impairment -> covers platelets so platelet activation is impaired
○ Renal failure in people, in dogs?
Packed red blood cells/whole blood what does it do, when used and how to increase
- Increase PCV and O2 transport capacity
- For acute haemorrhage
○ Replace what is lost (estimate)
○ Target PCV > 20% - To increase PCV by 1%
○ Packed red blood cells: 1ml/kg
○ Whole blood: 2ml/kg - Cats: always blood type
Rates and volumes of resuscitation fluids what are the 5 things it depends on
- Species
- Severity of hypoperfusion
- Presence of risk factors
- Type of fluid used
- Response of patient
What is the blood volume of dogs and cats
- Dogs: -90ml/kg
- Cats: -50-60ml/kg
Assessment of shock how occurs
- Resuscitation endpoints -> what is your endpoint, what is your heart rate target, mentation etc. (measured)
- You may also stop if you hit a safety endpoints (measured) -> crackles in lungs etc
Assessment of sock -> fluid aliquot -> assessment of shock -> fluid aliquot (adjust if needed) -> assessment of shock etc until NO SHOCK
What occurs with body weight and fluid therapy equations
- Higher body weight more variance in fluid therapy totals depending on formula -> need to be careful with horses
How is Poiseuilles law important with needles and flow
- According to Poiseuille’s law an increase in the radius by 2times will increase the flow rate by 16 times
○ In larger animals need to use a larger radius for more flow
What is a balacned fluid therapy, what are the 2 main types of fluids and are they balanced
- Balanced fluid therapy: isotonic to plasma and electrolytes similar
○ Lactated ringers solution - balanced
○ Normal saline - not-balanced
What is the maximum osmolality of fluids safety administered into peripheral vessels and why
600mOsm/L
○ Due to damage to vessels leading to phlebitis
○ If need to give more administer via central veins
What is the difference between PCV and Haematocrit
PCV = manual measurement
Haematocrit HCT = RBC count x RBC volume
RBC indices define MCV, MCH, MCHC, RDW and NRBC
MCV - mean corpuscular volume = average size
MCH - mean corpuscular haemoglobin = total Hb per cell
- less accurate
MCHC - mean corpuscular haemoglobin concentration = concentration of Hb in each cell
- more accurate
RDW - red cell distribution width (measure of anisocytosis/size variation)
- If large size variation and low MCV generally due to lower average size RBCs etc.
○ Best way to check is via the smear
NRBC - nucleated red blood cells
What are the 3 main questions in assessing anaemia and differentiation
- Regenerative or non-regenerative anaemia
○ Loss (haemorrhage, haemolysis) - regenerative -> reticulocytes or polychromatophils present
○ Decreased production - non-regenerative - Is the protein level low, normal or high
○ If haemorrhaging red cells and plasma lost -> losing protein so low protein
○ Haemolysis -> only destroying RBCS -> normal protein
○ Internal haemorrhage -> protein level can be close to normal as reabsorbed - Are there clues on the blood film
○ Oxidative damage, sheer injury -> haemolysis
○ Haemangiosarcoma
What are the 3 types of anaemia
- Regenerative = elevated reticulocyte count
○ Increased RBC loss - haemorrhage or haemolysis - Non-regenerative = normal or low reticulocyte count
○ Reduced rbc production - chronic disease/inflammation, marrow disease, iron deficiency - Pre-regenerative = too soon since RBC loss for an apparent marrow response to be evident in the blood
leukogram what are the 3 main types and characteristics
- Is there evidence of an inflammatory response?
○ Neutrophilia and/or monocytosis
○ Left shift (bands) or toxic change -> ALWAYS INFLAMMATORY - Is there evidence of stress response?
○ Lymphopenia (most consistent finding)
○ +/- mature neutrophilia
○ +/- monocytosis (dogs) - Is there a physiologic leucocytosis?
○ Mature neutrophilia and lymphocytosis in young animal
