Final: Chemical Restraint and sedation for minor procedures, Anesthetic considerations for trauma patients and C-sections, Common misconceptions in anesthesia

Question 1

Chemical restraint and sedation for minor procedures

Which drug has a dose dependent length of action that provides good analgesia and sedation in dogs and cats but is short in horses?

Answer 1

Dexmedetomidine

Question 2

Chemical restraint and sedation for minor procedures

Which drug becomes valuable in fractious or angry patients?

Answer 2

Ketamine

it can be asborbed transmucosally.

Thay also respond well to alfaxalone

Question 3

Chemical restraint and sedation for minor procedures

What drugs do you use for sick patients? what drugs do you only want to use in healthy patients?

Answer 3

Benzos, alpha 2s

Question 4

Chemical restraint and sedation for minor procedures

Which drug is discouraged in small animals? What is a go to sedation combination in our small and large animal species?

Answer 4

avoid xylazine

SA: alfaxalone and dexmedetomidine
LA: telazol, ketamine, dexmedetomidine or BAM (butorphanol, azeperone, medetomidine)

Question 5

Anesthetic considerations for trauma patients

What abnormalities are associated with lung contustions?

Answer 5

Affect oxygenation and ventilation: Prone to atelectasis, Hypoxemia/hypoventilation, Depending on severity

May require IPPV, BUT….
Risk for barotrauma/pneumothorax
Low peak insp. pressures (↑ RR)
PEEP (positive end-expiratory pressure)

Question 6

Anesthetic considerations for trauma patients

What abnormalities are associated with (TENSION) pneumothorax?

What happens to circulation?

Answer 6

atelectasis, hypoxemia

decreased lung compliance, sudden drop in BP (decreased venous return), CV collapse

TENSION pneumothorax: entrapment of air compressing on things in thorax

Question 7

Anesthetic considerations for trauma patients

What abnormalities are associated with diaphragmatic hernia?

Answer 7

Decreased FRC (functional residual capacity), atelectasis, hypoxemia

Question 8

Anesthetic considerations for trauma patients

What abnormalities are associated with myocardial contusions?

What drugs do you want to avoid?

Answer 8

Arrhythmias
VPC, may be worse with anesthesia, treat if it is compromising circulation (O2, fluids, analgesia, lidocaine)
Preop ECG
Avoid arrhythmogenic drugs (alpha 2 agonist, thiopental, halothane)

Question 9

Anesthetic considerations for trauma patients

What abnormalities are associate with hemorrhage?

How will it effect drug uptake? why?

Answer 9

Hypovolemia, hypotension
Anemia, hypoproteinemia (decreased oxygen delivery, reduced drug binding)

Question 10

Anesthetic considerations for trauma patients

What abnormalities are seen with a ruptured bladder?

a COMMON occurence*

Answer 10

Uroabdomen, azotemia, decreased Na and Cl, increased K

Hyperkalemia is the most severe, raises resting membrane potential, life-threatening arrhythmias.
Prolonged PR, tented T waves, loss of P waves, widening of QRS, v-fib/asystole

Anesthesia can worsen arrhythmias, have a continuous ECG, normalize K before anesthesia, catheterization (drain urine), supplement with Ca++, sodium bicarb, insulin/dextrose

Question 11

Anesthetic considerations for trauma patients

What abnormalities are seen with head trauma?

What drugs do you want to avoid?

Answer 11

Increase in intracranial pressure, mentation/ pupil size, cushing’s reflex (hypertension and bradycardia), changes in breathing pattern

Anesthesia can alter blood flow to brain: intubation can spike ICP (lidocaine lowers ICP), IA affects cerebral autoregulation, PaCO2 needs to be maintained WNL (PPV), avoid drugs that increase ICP

Ketamine increases ICP
Propofol and alfaxalone comes with hypotension and apnea but decreases ICP

Question 12

Anesthetic considerations for trauma patients

What are some neuroleptoanalgesics we use in our veterinary species?

CV sparing drugs…

Answer 12

Opioids and sedative/tranquilizer

Fentanyl and midazolam/diazepam

CV sparring (etomidate?): Etomidate and midazolam/diazepam is the most CV and respiratory sparing. Good in cats (HCM), short immunosuppression, remember to dilute etomidate due to hemolysis.

Use Anticholinergic if there is bradycardia (atropine, glycopyrrolate)

Question 13

Anesthetic considerations for trauma patients

What do consider for maintenance and continuous infusions?

Answer 13

balanced anesthesia, easily titratable, reduce MAC

Continuous infusions with: opioids, low dose ketamine, low dose lidocaine (not for cats, increased sensitivity and negative cardiovascular effects), regional anesthesia

Question 14

Anesthetic considerations for c-section and neonates

What are some physiologic changes and perioperative concerns during pregnancy?

cardio changes, respiratory changes, amount of anesthesia, GI

Answer 14

increased blood volume, plasma greater than RBC, can be seen as “anemic”

a pregnant uterus displaces the abdomen, O2 consumption increases by 20% (ventilation, TV, RR). increased progesterone increases sensitivity to PaCO2 (Preoxygenate!!)

anesthetic requirements decrease 25-40%, there is a high risk of overdose

GI changes, emptying, regurge

Question 15

Anesthetic considerations for c-section and neonates

What are the basic anesthetic protocols to maintain?

Answer 15

Maintain BP, avoid rapid desaturation (hypoxemia), correct electrolytes (Ca++), minimize doses

Question 16

Anesthetic considerations for c-section and neonates

(LA and SA) What kind of drugs do you want to use?

premed, induction, maintenance and post op

Answer 16

Reversible or short acting, minimize CV effects, pros and cons to premeds, local anesthesia, titrate drugs carefully.

Premeds
SA: opioids and anticholinergics.
LA: alpha 2 agonists
Ruminants: benzos or no premedication

Induction IV only (mask induction too long and stressful)
Propofol or alfaxlaone preferred in small animal. Etomidate or fentanyl in special cases.
Ketamine and propofol (benzo) in LA
Give time (about 15 minutes) for drug induction

Maintenance IA, avoid nitrous oxide, low dose, with local anesthetic

Post op: incision block, morphine epidural, systemic opioids, NSAIDs

Question 17

Anesthetic considerations for c-section and neonates

What is the care involved for a neonate post c-section?

Answer 17

Should have one person for every neonate.
Resuscitation: Clear oropharynx of secretions. Antagonize drugs. Rub chest vigorously to stimulate respiration. Intubate if not breathing. Acupuncture at GV26 (at the nose to stimulate breathing)

Doxapram is controversial, increases O2 consumption but not if the patient is already hypoxemic.

Question 18

Anesthetic considerations for c-section and neonates

What are some anesthetic concernc for the neonate post c-section?

Answer 18

Decreased ability to metabolize drugs (low liver enzymes), hypoglycemia (again with the liver, low glycogen stores, want to maintain glucose >70 mg/dl), hypothermia (greater surface area to body weight), bradycardia (immature sympathetic nervous system. Avoid bradycardia, anticholinergics if necessary), hypotension (want MAP>50 mmHG), this is less than an adult, ephedrine if it gets too low), hypoventilation (they have increased thoracic compliance and weak muscles) > which makes them susceptible to atelectasis.

if drugs cross BBB, they cross the placenta

Question 19

Common misconceptions in anesthesia

What are some anesthetic considerations for our greyhound breeds?

Answer 19

With Thiobarbiturates, they have a delayed recovery (3-4x) longer and because of their lower liver enzymes, they do not metabolize the drugs as rapidly.

Hyperkalemia: etiology is unknown and is often subclinical but it can be life-threatening.

Their mutant DEPOH gene makes them prone to bleeding disorders and post-operative hemorrhage. There is hyperfibrinolysis; antifibrinolytic drugs help.

Question 20

Common misconceptions in anesthesia

What are some anesthetic considerations for our collie breeds?

what about in cats?

Answer 20

The MDR1 genes in collies (first identified with ivermectin) (shelties, Aussie shepherds, and whippets) predisposes them to prolonged sedation as this is the gene that provides a functional p-glycoprotein which is needed for the BBB. So, may want to avoid acepromazine and butorphanol.

Also, have a MDR1 mutation. Experience neurotxicity with eprinomectin. Seen in NON-PURE bred Maine coons.

Question 21

Common misconceptions in anesthesia

T/F you should not use acepromazine in Boxers ever

Answer 21

Acepromazine increases vagal response and can lead to collapse. But have been used without issues, use with caution.

Question 22

Common misconceptions in anesthesia

Myth: a strong pulse indicates good blood pressure and tissue perfusion

What is the truth?

Answer 22

A strong palpable pulse just means the difference between systolic and diastolic pressures, it does not rule out hypotension. Not only old and sick patients get hypotensive during anesthesia, many young and healthy, too. Decrease anesthetic depth, give a bolus of IV fluids and inotropes. Can only tell a patient is hypotensive if you measure it*