Anesthesia of complicated patient

Question 1

ASA physical status
classification system: describe ASA I

Answer 1

healthy patient

Question 2

ASA physical status
classification system: describe ASA II

Answer 2

patient suffering from a mild systemic disease

ie. rhinitis

Question 3

ASA physical status
classification system: describe ASA III

Answer 3

patient suffering from a severe systemic disease

ie. chronic kidney disease

Question 4

ASA physical status
classification system: describe ASA IV

Answer 4

patient suffering from severe systemic disease that is a constant threat to life.

ie. DKA, dilated cardiomyopathy with clinical signs, neonatal intussusception

Question 5

ASA physical status classification system: describe ASA V

Answer 5

dying patient, who is not expected to survive without surgery

ie. GDV or spleenic rupture etc.

Question 6

ASA physical status classification system: describe ASA VI

Answer 6

declared brain-dead patient

this is used in human med

Question 7

kidneys constitute 0.4% of the whole body mass, but receive what % of cardiac output?

Answer 7

receive 20–25% of cardiac output (more blood per 1 g of tissue than a working muscle)

Kidney oxygen requirement is higher compared to any other tissue.

Sufficient kidney blood flow is a prerequisite of its normal functioning.

Question 8

What 3 potential consequences of anesthetics can aggravate kidney disease

Answer 8

Pain, hypoxemia, and hypotension aggravate kidney disease

In these cases try to keep МАР > 70-80 mmHg via IVFT etc.

Question 9

Basic rules for anesthetic drugs used in a chronic kidney disease patient: (3)

Answer 9

1. Preserve the function of cardiovascular system
2. Must be excreted via kidneys only in an already once metabolized form
3. Guarantee sufficient analgesia

Note: these patients tend to lose total protein

Question 10

Drugs in free form (ie. low TP patient) are more likely to cause

Answer 10

side effects

Question 11

Can you use ketamine in kidney disease cats?

Answer 11

No because In cats, ketamine is only excreted intact (non metabolized) via kidneys and thus, is contraindicated in case of
kidney disease. Ketamine metabolites are also acidifying.

Question 12

Can you use atropine in kidney disease cats?

Answer 12

try to avoid it. only use if direct indication and try to keep dose as low as possible.

30–50% of atropine passes intactly into kidneys.
This medicine is only used in case of severe
bradycardia.

Question 13

What premedications should you favor in kidney disease cats?

Answer 13

Premedication
- Methadone or butorphanol IV
- Midazolam or diazepam IV

• Acepromazine if needed (low dose! and only if the cat patient won’t tolerate an iv catheter conscious)

Question 14

What anesthetic drugs should you avoid in kidney disease cats? (3)

Answer 14

ketamine (excreted into urine)
atropine (use only low dose if needed)
alfa2-agonists (produce vasoconstriction and bradycardia which decrease kidney perfusion)

(and gabbapentin)

Question 15

3 main/broad functions of the liver:

Answer 15

gluconeogenesis
plasma protein production
coagulation factors production

Question 16

What crystalloid should you favor for chronic liver disease patients?

Answer 16

Avoid ringer’s lactate if possible, favor ringer’s acetate or sodium chloride 0.9%

Question 17

Animals suffering from liver failure are
predisposed to muscle cramps during
anesthesia. Why?

Answer 17

Liver failure patients may have higher ketones (due to liver unable to perform gluconeogenesis) which cross the brain-blood-barrier and upon accumulation can cause seizures.

Question 18

What anesthetic drugs should you avoid in chronic liver disease dogs? (3)

Answer 18

In dogs, ketamine and tiletamine are entirely metabolized by the liver and may induce muscle cramps.

Acepromazine is entirely metabolized by the liver and may induce protein level decrease.

NSAIDs are not good for the liver

Question 19

What anesthetic drugs should you favor in chronic liver disease dogs? (4)

Answer 19

Premedication
- Methadone IV (opioids are quite liver-safe)
- Midazolam IV
If necessary: (dex)medetomidine IM (low dose and def reverse it later!)

Selective alpha-2-adrenomimetics increase blood pressure, induce bradycardia, but do not decrease blood flow in the liver and can be reversed.

Propofol, clearance: liver, kidneys, lungs: 2:2:1

Question 20

Liver receives ?% of cardiac output

Answer 20

Liver receives 20% of cardiac output

Question 21

what is enalapril

Answer 21

treats high blood pressure (hypertension) and heart failure

is an angiotensin-converting enzyme inhibitor.

Question 22

what drug is used in heart disease dogs to increase cardiac contractility?

Answer 22

pimobendan (Vetmedin)

Question 23

Cardiac output =

Answer 23

the amount of blood pumped by the left ventricle into aorta per minute, which is the
result of heart rate and stroke volume
(SV)

Question 24

Stroke volume =

Answer 24

the result of preload, afterload, and myocardial contractility

Question 25

What is the most dangerous anesthetic for heart disease dogs?

Answer 25

alfa2-agonists (cause bradycardia!, afterload but also preload will increase)

Question 26

What anesthetics should you favor in cardiac patients? (5)

Answer 26

etomidate if avail, alfaxalone next, propofol ok if neither former.
benzos and opioids are safe
ketamine is positively inotropic so yes

Question 27

Why would you want to review thoracic radiographs of a cardiac patient before anesthesia?

Answer 27

not actually to assess the cardiac silhouette but to assess the distension of the pulmonary blood vessels

Question 28

IVFT rate for cardiac patients

Answer 28

Cautious fluid therapy, do not exceed (3 – 5 ml/kg)

Question 29

Intra operative drugs for cardiac patients: (4)

Answer 29

dopamine and dobutamine infusions to improve contractility
lidocaine IV to avoid or treat PVCs

avoid atropine unless definitely indicated

Question 30

Physiological hypoalbuminaemia is seen in?

Answer 30

neonatal patients

Question 31

What to note in case of neonatal patients? (10)

Answer 31

High metabolic rate
High oxygen consumption

Unformed compensatory mechanisms
Underdeveloped sympathetic nervous system
Physiological hypoalbuminemia
Increased blood-brain barrier permeability
Low adipose tissue content
Gluconeogenesis is underdeveloped, very small glucose reserves in the organism

Kidney function (glomerular filtration and
function of kidney tubules) becomes fully
developed by the age of two months.

During the first 3–4 weeks, liver metabolism is underdeveloped.

Question 32

What anesthetic drugs should you favor in a neonatal patient? (4-5)

Answer 32

opioids (butorphanol, Methadone or morphine IV)
benzos (Midazolam IV)

Propofol/ alfaxalone
ketamine

Question 33

What anesthetic drugs should you avoid in a neonatal patient? (2)

Answer 33

Alpha-2-agonists induce dangerous
cardiovascular changes.

Acepromazine induces severe hypotension and thus is not suitable for animals younger than 6–8 months.

Question 34

In neonatal patients, bradycardia is more often caused by..? (2)

Answer 34

low temperature or hypoxemia.