Flashcards in Cardiovascular systeem, ECG, Blood pressure, and Temp Deck (46)
Should low tech monitoring be used even if specialized equipment is being used?
ECG, BP (doppler, ocillometric, direct)
Pulse ox, Expiratory.end tidal CO2
When should animals be monitored?
Anytime heavy sedation is produced; vigilence depends on how profound the sedation is
Anytime anesthesia is produced; regardless of condition/procedure/duration
What equipment can we use to assess heart rate?
1. Auscultation- stethoscope
2. Pulse oximeter- accuracy?
What does the parasympathetic system influence in respect to HR?
1. SA and AV nodes
2. Muscarinic receptors
Increase in parasympathetic tone results in bradycardia
What does the sympathetic system influence in respect to HR?
1. SA and AV nodes,
3. Alpha-1, Beta-1/2 receptors
Increase in sympathetic tone results in tachycardia
What increases parasympathetic tone? (Bradycardia)
Pressure on eyes/viscera
Profound anestthetic depth
High serum potassium
SA node disease
What causes increases in sympathetic tone? (Tachycardia)
Very elevated CO2
Does the ECG give accurate information about the function of the heart?
No, only the electrical activity
ECG for sinus arrhythmia
R-R variation congruent with respiration
Why do we monitor ECGs?
Detection of arrhythmias even if there is no history of one as they are common under anesthesia
ECG for sinus bradycardia
Regular increased R-R interval
Should sinus bradycardia be treated?
Only if HR is low enough to adversely effect CO or BP
Is the ECG the only thing that will tell us if we have an abnormal rhythm?
Yes, all other monitoring equipment will likely be normal
What is CO a product of?
HR and SV
Is CO easily monitored?
No, it requires an invasive catheter placed into the pulmonary artery
What are normal BPs?
Which BP value best represents systemic perfusion?
MAP should be maintained greather than _____mmHg to maintain renal perfusion
What are indirect ways to monitor BP?
Doppler ultrasonic flow
What are direct ways to monitor BP?
Arterial catheter and transducer recording system
What are some advantages to Doppler?
1. Continuous evaluation of pulse rate
2. Sudden loss of sound may indicate cardiac arrrest
3. Useful in tiny or exotic patients
4. Relatively inespensive
What are some disadvantages of doppler?
1. Requires and operator for BP
2. Subjective readings
3. No MAP
4. Difficult to capture if vasoconstriction/hypothermia/poor perfusion
In oscillometeric BP measurements, which values are recorded and which ones are calculated.
Calculated: systolic and diastolic
Advantages of Oscillometric BP monitoring
1. Measure mean and calculates syst/diast
2. Can be set to monitor at certain time intervals
3. Stores values for review
Disadvantages of Oscillometric BP monitoring
1. Relatively expensive
2. May not secure pressure at extremes of heart rate in abnormal rhythm
3. May not read if hypotensive
4. No monitoring in between readings
What kind of BP is produced if cuff is too small/loose?
What kind of BP is produced if cuff is too large/tight?
What happens to BP if the cuff is below the heart?
Should the limb be straight or flexed for BP measurements?
Which BP measurement type iss most accurate?
Depends on equipment/age/patient
Which arteries are used for direct BP measurement?
Small animal: Dorsal pedal, coccygeal, or radial
Large animal: Dorsal metatarsal, facial, caudal auricular, transverse facial
Where should the transducer be positioned in direct BP measurement?
Level of the heart
If too low= increased pressure
If too high= decreased pressure
What does the shape of the pressure wave tell us?
Narrow wave- vasodilation and low diastolic pressure
Increased slope- low inotropy, SV, CO
Electronic invasive BP facts
1. More expensive
2. Provides SAP, DAP, MAP, and waveform
3. Waveforms provides quality of inotropy and venous return
Sphygomomanometer invasive BP facts
1. Inexpensive and portable
2. Only provides mean
3. No waveform
Causes of Hypotension
3. Poor cardiac function
Causes of Hypertension
1. Light anesthesi
3. Drugs (catecholamines/ketamine
4. Disease processes (+ICP, renal/adrenal dz)
Why does anesthesia cause hypothermia?
Decrease of muscular activity, metabolism, and hypothalamic activity
Evaporative heat losses and anesthesia induced vasodilation
Issues when body temp decreases to 96-97F
Minimal, some shivering may occur
Only an issue for cardiac/pulmonary paitents
Issues when body temp decreases to 92-94F
Decreases anesthetic requirement but prolongs recovery
Will not shiver in recovery
Issues when body temp decreases to 89-90F
HR/CO decreases and may not respond to tx, may interfere with healing mechanisms and slows recovery
Do all animals require heat support?
Heavy coated dogs may become hyperthermic with additional heat support
Should temp be monitored through recovery?
Yes, until the animal is normal
1. Bair huggers
2. Warm water circulating pads/blankets
3. Pads/towels between patient and open surfaces