troubleshooting and emergency events

what are common anesthesia problems and and emergencies

1. animals that wont stay anesthetized

2. animals too deeply anesthetized

3. pale MM and porlonged CRT

4. hypotension

5. dyspnea and/or cyanosis

6. tachypnea

7. cardiac rate and rhythm abnormalities

8. cardiac arrhythmias

3 things why would a patient not stay anesthetized

• Inadequate vaporizer setting

• Blocked, misplaced, or disconnected ET tube

• Inadequate O2 flow

what is the minimum flow rate for most circuits

500 ml/min

sings of an animal too deeply anesthetized

• RR of <6 rpm, shallow respirations, or exaggerated effort

• Pale or cyanotic MM, CRT <2 sec

• Bradycardia, weak pulses

• SBP <80 mmHg

• Cardiac arrhythmias

• Cold extremities, hypothermic

• Absent reflexes, flaccid muscle tone, dilated pupils

• Absent PLR

how to respond if patient too deep

• Inform the vet, immediately decrease vaporizer setting

• Ventilate animal with 100% O2

• Check vitals and discuss if IVF bolus is required

• Add external heat sources

• Consider reversal agents

how to give IPPV

1. Close the APL valve, make sure reservoir bag is filled

2. Gently squeeze bag until animals chest rises slightly

3. Open APL valve immediately after giving a breath

4. Repeat every 5 seconds until animal recovers → increased HR, stronger pulses, MM pink

when should you give IPPV

if patient cant/is not breathing on their own, if not deep enough, if hypoxic,

which agents will cause vasodilation and hypotension

inhalant agents or IV induction

which agents will cause vasoconstriction and hypertension

alpha-2 agonists and catecholamines

how to treat pale MM and prolonged CRT

• check depth

• use warming devices

• check BP/volume

• rule out other possibilities

administration rate of crystalloid fluids if hypotensive

5-10 ml/kg over 15 min

what drug category can help treat hypotension

sympathomimetics

why does cyanosis occur

tissue oxygenation is inadequate

how to treat dyspnea and cyanosis

• Ensure O2 is being delivered

  • Ventilate with 100% O2 until MM color improves or pulse ox reading rises to 95%

• Administer IV fluids or emergency drugs (doxapram)

• Observe during resuscitative efforts for signs of cardiac arrest

• Supplemental O2 continued into recovery period

  • Keep on O2 until extubated, may need a mask

what can tachypnea be caused by

 Hypoxemia, hypercarbia, and inadequate depth

what are common abnormalities in cardiac rate and rhythm

• bradycardia

• tachycardia

• arrhythmias

what effect does vagus nerve stimulation have

bradycardia

how to treat vagus nerve stimulation

anticholinergic (atropine or glycopyrrolate)

what drugs can cause bradycardia

alpha-2’s or opioids

what other vital sign should you consider when bradycardia is present

blood pressure

bradycardic range for dogs and cats (anesthetised)

• Dogs: <60-70 bpm

• Cats: <120 bpm

which drugs cause tachycardia

• Anticholinergics (atropine)

• dissociatives (ketamine)

• catecholamines (epinephrine)

stage 3 anesthesia tachycardia rates

• Large dog: >140 bpm

• Small dog: >160 bpm

• Cats: >200 bpm

what can cardiac arrhythmias be cause by

Anoxia, hypercarbia, poor tissue perfusion, drug administration, inhalant anesthesia, acid/base imbalances, myocardial damage, concurrent pulmonary disease

what are cardiac arrhythmias

Several ECG abnormalities

• Dropped beats, VPCs, sustained episodes of tachycardia

when are cardiac arrhythmias common

light sedation

how to treat arrhythmias

• Rule out inadequate O2 flow or CO2 accumulation

• Increased periodic intermittent manual ventilation bagging

• Anti-arrhythmic drugs

• +/- electrical defibriliation

hypotensive vital signs

• SAP = <80 mmHg

• MAP = <60 mmHg

• DAP = <40 mmHg

if hypotensive and HR is also low how can you treat

with an anticholinergic (CO= HR x SV)

• Glycopyrrolate: 0.005-0.01 mg/kg IV

• Atropine: 0.02 mg/kg IV

how does HR indirectly affect BP

because BP = CO x SV and CO = HR x SV

what other drug can you use if hypotension persists after giving an anticholinergic

sympathomimetic (Dopamine CRI) or injection of Epinephrine

what bolus rates can you give for hypotension

crystalloid fluid bolus

• 5-10 ml/kg over 15 min in large, healthy animals

• 2-5 ml/kg over 20 min for geriatric or cardiac patients

If persists, a colloid fluid can be considered (2-5 ml/kg over 10-15 min)

abnormal hypertensive vitals

• SAP = >160 mmHg

• MAP = >120 mmHg

• DAP = >100 mmHg

what could hypertension be due to

• drugs

• patient is too light

  • Turn up inhalant to achieve surgical plane

  • If waking up, give top-up dose (1/4) of induction agent

abnormal bradycardia vitals

• Large dogs = <60 bpm

• Medium dog = <90 bpm

• cat/small dogs = <120 bpm

which drug is it okay to tolerate a lower HR, if BP is also normal

dexmedetomidine

drugs that can decrease HR

opioids

what drugs can treat bradycardia

anticholinergic or an antagonist

abnormal tachycardia vitals

• Large dog = >150 bpm

• cat/small dog = >180 bpm

what could be reasons for tachycardia

• drugs

• hypovolemia

• hypercarbia

• hypoxic

• hyperthermic

• electrolyte imbalances

abnormal SPO2 vitals

Mild: SPO2 = <95%

Moderate: SPO2 = 80-90%

Severe: SPO2 = <80%

what is hypoxemia usually secondary to

increased RR, HR, SV, and SVR

what can occur if hypoxemia is untreated

agonal breathing, vasodilation, decreased HR + BP, cardiac arrest

what equipment do you check if hypoxic

Pulse Oximeter

abnormal ETCO2 vital

>60 mmHg

what equipment do you check if hyper/hypocarbic

capnograph

why could a patient be hypercarbic

• decreased RR → increased CO2

• too deep

• drugs to cause respiratory depression

abnormal hypocarbia vital

<35 mmHg

what might you see if hypocarbic

vasoconstriction and compensatory hypoventilation