Peri-anesthesia Monitoring and Complications II

The most ideal heart rate is a ____?

Resting heart rate

Large dogs have what resting HR?

35-100 Bpm

Medium dogs have what resting HR?

50-120bpm

Small dogs have what resting HR?

80-150bpm

Cats have what Resting HR?

90-160bpm

Horses have what resting HR?

25-45

If a patient has an arrhythmia or severe bradycardia how to should you measure HR?

Count over 20-30 and multiply by 3 or 2

What will an ECG tell you?

Only electrical signal

Should you place ECG first?

No - always place capnograph and pulseox first

Small animals will use what leads?

Lead 2

Horses and cattle will use what kind of leads?

Base-apex lead (Lead 1)

Where is the proper placement of the lead on large animals?

White -on neck

Red - FR

Black - FL

What is the purpose of ECG?

Find obvious arrhythmias and major changes

You can use the ___ if forelimbs aren't accessible?

Ears

Is this a a normal ECG?

Yes for large animals and birds

What breed naturally gets sinus bradycardia under anesthesia?

Miniature dachshunds

What will sinus bradicardia going to look like on ECG?

Longer R-R

What is going to cause vagal sinus bradycardia?

-Anesthesia

-Opioids

-Sedatives

-Hypothermia

-Neck/abdomen/ manipulation

What is going to cause non-vagal sinus bradycardia?

Cardiac dz

Endocrine dz

Electrolyte abnormality

Beta blockers

Ca2+ channel blockers

When do we tx sinus bradycardia?

Hypotension

What animals is sinus bradycardia dangerous?

Young - neonates esp if hypotensive

-fixed sv so HR dependent CO

How can tx vagal bradycardia?

Anticolenergis

- Atropine (less potent, most efficacious 60min)

- Glycopyrrolate (Less efficacious but more potent 90min)

Which drug used to tx sinus bradycardia will be more likely to cause tachycardia and should be used in emergency situations?

Atropine,

(glycopyrrolate might not work and need multi-doses)

What interactions will anticholinergics have w/ A2 agonists?

Increased work load due to A2 causing vasoconstriction and Anticolinergic causing increased HR

You should avoid using an anticholinergic for ____ after use of dexmedetomine?

60mins

What is paradoxical bradycardia caused by anticholinergics?

A decrease in HR or AV block that will resolve w/ time

How do you tx non-vagal bradycardia?

Stop the cause

Isoproterenol - Nonselective B agonist

Pacemaker

What will we see on the ECG if we have sinus Tachycardia?

RR interval will be shorter

What will happen physiologically w/ sinus tachycardia?

Shorter diastolic period - less filling time

Less coronary perfusion

Decrease CO b/c smaller SV

What are causes of sinus tachycardia?

High Sympathetic tone - less depth, pain

Compensatory response (baro/ hypovolemia/ hypotension)

High sympathetic tone will have __ in BP and HR, Compensatory response will have ____ in BP and HR?

Increased

Separation

How do you tx High sympathetic tone sinus tachycardia?

More analgesics

Increase vaporizer

How do you tx compensatory response sinus tachycardia? ?

Decrease vaporizer

Volume replacement (5ml/kg fluid bolus)

Colloid

Tx hypotension

If the tachycardia is persistent in Hight SNS tone sinus tachycardia what drugs can we use to tx?

Esmolol -Beta antagonist (give loading dose and CRI)

Diltiazem - ca2+ channel blocker (refrigerated)

What is a respiratory sinus arrhythmia?

Benign arrhythmia due to decrease in pleural pressure during inspiration - increase in venous return, volume in R atria and stimulating stretch receptor while increasing HR. Will stop w/ cessation

How do you tx respiratory sinus arrhythmia?

No tx necessary

What an AV block 1ST degree?

Delay in transmission, PR interval is prolonged but every P wave has a QRS complex

What causes AV block 1ST degree?

Vagal tone

Drugs - beta blockers, Ca2+ channel blockers

Electrolyte abnormalities

Heart dz

Should you tx AV block 1ST degree?

No tx needed - very minor

What is a AV 2nd degree block?

Intermediate failure of AV conduction - not all P waves have a QRS complex - occasional drops

What is mobitz type 1 AV 2nd degree block?

Vagal - prolonged P-R intervals before beat drops

What is Morbitz type 2 AV 2nd degree block?

A pathological condition in which there is no prolongation of P-R interval before dropped beat - sudden drops

When do you tx AV 2nd degree block?

If hypotensive or progressing severely w/ time

Type 1 AV 2nd degree block is treated w/ _____ and type 2 is treated w/ ___?

Anticholinergics - type 1

Pacemaker - type 2

What is a 3rd degree AV block?

Complete AV dissociation - no relation between P and QRS complex - PP and RR are constant

What are most common cause of 3rd degree AV block?

Pathological

-heart dz

-hyperkalemia

-digoxin tox

What is the severity of a 3rd degree AV block dependent on?

Ectopic pacemaker location (junctional better. ventricle can have problems)

What animals will have asymptomatic 3rd degree AV block?

Cats - adequate ectopic pacemaker rates

What is tx of 3rd degree AV block?

Pacemaker

Stop procedure if possible

What is a ventricular premature complex (VPC)?

Depolarization of ectopic area in ventricle that is more rapid and premature than signal at SA node

-missing P wave,

-shorter RR interval,

-wide bizarre QRS complex

What are common causes of ventricular premature complex (VPC)?

Reentery - (something wrong with the heart)

High SNS tone - GDV, pain, high stress

How can you tell if ventricular premature complex (VPC) is clinical needing tx?

Pay attention to pulseox wave and if AUC of each triangle is large enough you still have an adequate stroke volume

When do you have V-tach?

4 or more VPC in succession at more than 160 BPM

What do you do if the pet is in V-tach?

Check for pulse

-no pulse - CPR - Cardiac arrest

-Pulse - correct hypotension

What is tx for VPC/ V-tach?

Lidocaine -Na+ channel blocker B1 antiarrythmics

Procainamide - class A1

What is an accelerated idioventricular rhythm

slow V-tach - alternating between 2 sites - no tx nessasary

When are accelerated idioventricular rhythm most common?

GDV,

splenic dz

What is an escape beat?

Normal spontaneous depolarization of junctional or ventricular pacemakers - safety system in cases of conduction failure

Escape beats will alway follow a ___ and should ___ be treated?

Pause

Not be treated as VPC (can use anticholinergics