what are complications related to HR, pressure and volume?
Heart rate
o Bradyardia
o Tachycardia
o Arrhythmias
Pressure
o Hypotension
o Hypertension
Volume
o Hypovolemia
o Hypervolemia
what considerations do we have to think about when it comes to heart rate?
-age; neonatal animals will have higher HR than adults
-size/breed; especially for dogs
-resting heart rate; know what their normal is because it could be different from what you would expect
what does a high ETCO2 indicate
good cardiac output
what happens when there is bradycardia
what is the most important parameter for HR
cardiac output
causes of increased parasympathetic activity in bradycardia cases and examples
Vagal tone
▪ Oculocardiac reflex (trigeminovagal)
▪ Increase pressure in GI
▪ During expiration
Drug induced
▪ Alpha 2-agonists (xylazine, romifidine, detomidine, dexmedetomidine)
▪ Opioids (morphine, butorphanol, hydromorphone, fentanyl)
Reflex mechanism due to hypertension
▪ Baroreflex response (Alpha 2 agonists, Cushing reflex, primary
hypertension…)
what is the most common change we see with anesthesia
Hypotension
when there is bradycardia there is an ______ in parasympathetic activity
increase
what can cause bradycardia? (4)
▪ Cardiac disease; Sick sinus syndrome
▪ Increased intracranial pressure; Cushing’s response
▪ Electrolyte abnormalities; Hyperkalemia
▪ Hypothermia (less than 35 °C)
when do we want to treat bradycardia
▪ Treat if marked bradycardia
▪ For example: Dog with a HR of 38 versus 58
▪ Treat if hypotension or low cardiac output is associated. Is your BP high or low?
▪ Treat if rhythm is markedly irregular and/or dysrhytmias are also present
how to treat bradycardia if the cause is due to vagal tone
anticholinergics
how to treat bradycardia if the cause is drug induced
-reversal, lidocaine
-anticholinergics
how to treat bradycardia if the cause is due cardiac disease
-anticholinergics
-isoproterenol
-pacemaker
how to treat bradycardia if the cause is due to hypertension
control hypertension
how to treat bradycardia if the cause is due to increased intracranial pressure
-control ICP
how to treat bradycardia if the cause is due to hypothermia
warm up
how to treat bradycardia if the cause is due to electrolyte abnormalities
-decrease K+
-calcium gluconate
what happens to CO/BP and filling of chambers when there is tachycardia
treatment of tachycardia if the cause is due to superficial plane and/or pain
check depth/analgesia
what can cause tachycardia as a result of increased sympathetic activity (6)
▪ Superficial anesthetic plane and/or pain
▪ Hypotension/hypovolemia
▪ Hypercapnia/Hyperthermia
▪ Drug induced
-Ketamine
-Sympathomimetics
-Anticholinergics
▪ Specific diseases: Phaeochromocytoma, Hyperthyroidism, Heart disease
▪ Hypoxia/Shock
tachycardia is from ______ sympathetic activity
increased
treatment of tachycardia if the cause is due to hypotension/hypovolemia
correct fluids/sympathomimetic
treatment of tachycardia if the cause is due to hypercapnia/hyperthermia
adjust ventilation/cool down
treatment of tachycardia if the cause is drug induced
stop administration