Introduction and Medical Math

Question 1

What is anesthesia?

Answer 1

lack of sensation or feeling, or an unconscious state with amnesia, analgesia, and suppressed reflexes

Question 2

What is analgesia?

Answer 2

absences of pain in response to an otherwise painful stimulus

Question 3

What is nociception? Does it require consciousness?

Answer 3

neural process that underlies the conscious perception of pain

no - can occur with general anesthesia

Question 4

What is the difference between local, regional, and general anesthesia?

Answer 4

LOCAL - loss of pain sensation in a circumscribed body area

REGIONAL - loss of pain sensation in a body area that is defined by a pattern of effected nerves (femoral-sciatic nerve block used for TLPOs)

GENERAL - drug-induced unconscious state gained by reversible and controlled depression of the CNS and perception

Question 5

What are 2 requirements for general anesthesia?

Answer 5

1. inhibition of transduction, transmission, and modulation of nociceptive stimuli (patient will not be aroused by painful/noxious stimuli, like towel clamps)
2. depressed/attenuated sensory, motor, and autonomic reflexes

Question 5

What is the difference between tranquilization and sedation?

Answer 5

T = behavioral change with relief of anxiety, but continued awareness of surroundings (anxiolytics)

S = central depression with drowsiness and relaxation; patient is unaware, but arousable to noxious stimuli

Question 6

What is the difference between narcosis and hypnosis?

Answer 6

N = deep sleep state with difficult arousal

H = trance, sleep state with easy arousal

Question 7

What are the 4 requirements for surgical general anesthesia?

Answer 7

1. unconsciousness
2. amnesia
3. muscle relaxation
4. hypoalgesia

Question 8

What is balanced anesthesia? What are 4 requirements?

Answer 8

anesthesia achieved with multiple drugs and techniques used simultaneously

1. amnesia
2. antinociception
3. muscle relaxation
4. suppressed autonomic reflexes

Question 9

How do dogs and cats compare with sedation and anesthesia risk?

Answer 9

DOGS = 1.7 in 1000 have anesthesia-related mortality

CATS = 2.4 in 1000 have anesthesia-related mortality

(EQUINE = 0.08-1.8% mortality)

Question 10

What are the most common causes of anesthesia-related mortalities in dogs and cats?

Answer 10

DOGS = emergencies, no physical exam, underweight, anemia

CATS = emergencies, smaller size, intubation, IV fluid overload

Question 11

What are 3 signs of CNS depression gained by anesthesia?

Answer 11

1. loss of consciousness
2. dampening of reflexes - hypotension, hypoventilation, hypothermia
3. modulation of nociception - analgesia, antinociception

Question 12

What are 4 sigsn of cardiovascular depression gained by anesthesia?

Answer 12

1. reflex suppression (baroreceptor)
2. changes in autonomic balance
3. changes in vasomotor tone
4. myocardial depression (direct = drugs; indirect = hypoxemia, hypercapnia, acidosis)

Question 13

What are 5 signs of respiratory depression caused by anesthesia?

Answer 13

1. reflex suppression - decreased ventilatory response to increased PCO2 and decreased pH and PO2
2. reduced respiratory muscle activity
3. alveolar collapse/small airway closure (atelectasis)
4. reduced functional residual capacity
5. increased ventilation/perfusion mismatch

Question 14

1 g = ______ mg
1 mg = _____ ug
1 ug = ______ mg

Answer 14

1000 mg

1000 ug

0.001 mg

Question 15

How may mg/mL is 2% Lidocaine?

Answer 15

2% = 2g/100mL
= 2000mg/100mL = 20mg/mL

Question 16

How many mg is 25 ug?

Answer 16

25/1000 = 0.025 mg

(25 ug x 0.001mg/1ug)

Question 17

How many mg/mL is a 50% solution of dextrose?

Answer 17

50% = 50g/100mL
= 50000mg/100mL = 500mg/ml

Question 18

Our maximum dose of bupivacaine is 0.4 mL/kg of 0.5% bupivacine. How many mg/kg is the max dose?

Answer 18

0.5% = 0.5g/100mL
= 500mg/100 mL = 5mg/mL

(5mg/mL) x (0.4mL/kg) = 2 mg/kg

Question 19

What is the most common dilution?

Answer 19

1:10 —> 1 part drug, 9 parts diluent (saline) = 10 mg/mL

1:100 —> 0.1 part drug, 9.9 parts diluent = 1 mg/mL

Question 20

How can 40 mg/mL of dopamine be diluted to 4 mg/mL?

Answer 20

add 1 mL of dopamine (40mg) plus 9 mL saline given 40 mg in 10 ml = 4 mg/mL

Question 21

How can 40 mg/mL of dopamine be diluted to 5 mL of 10 mg/mL?

Answer 21

5 mL x 10 mg/mL = 50 mg
50mg/(40 mg/mL) = 1.25 ml of stock dopamine
5-1.25 = 3.75 ml saline

Question 22

If a 20 kg dog is receiving Fentanyl at 5 ug/kg/hr and fluids are at 5 mL/kg/hr, what is the CRI?

Answer 22

20kg x (5ug/kg/hr) = 100 ug/hr
(100ug/hr)/(50ug/mL) = 3 mL/hr

Question 23

How can a 5ug/mL solution of 50ug/mL stock Fentanyl be made in a buretrol? What is the drip rate (1 mL = 60 drops)? Total anesthetic maintenance fluids?

Answer 23

40 mL of 5 ug/mL = 200 ug of Fentanyl
4 mL of 50ug/mL stock = 4 mL, add 36 mL saline

(100 ug/hr)/(5ug/mL) = 20 mL/hr
((20 mL/hr) x (60 drops/min)/60 min/hr = 20 drops/min
in a 60 drop/mL drip, mL/hr = drops/min

total anesthesia fluids = 100 mL/hr
100-20 = 80 mL

Question 24

A 20 kg dog is receiving 5 ug/kg/min of dopamine delivered at 2 mL/hr. What is the CRI? If dopamine stock is 40 mg/mL how should it be diluted?

Answer 24

20 kg x (5 ug/kg/min) = 100 ug/min
100 ug/min x 60 min = 6000 ug/hr

6000ug/2ml = 3000 ug/mL

make 20 mL = 60000 ug
60000ug/(1000ug/mg) = 60 mg

60mg/(40mg/mL) = 1.5 mL dopamine
1.5 mL dopamine + 18.5 saline = 20 mL of 3 mg/mL

Question 25

Dopamine stock is 40 mg/mL. How would you make a syringe of 10 mL dopamine that is 5 mg/mL? A 5 mL syringe that is 20 mg/mL?

Answer 25

10 mL x (5 mg/mL) = 50 mg
50 mg / (40 mg/mL) = 1.25 mL of stock
1.25 mL dopamine stock + 8.75 mL of saline = 10 mL

5 mL x (20 mg/mL) = 100 mg
100 mg / (40 mg/mL) = 2.5 mL of stock
2.5 mL dopamine stock + 2.5 mL saline = 5 mL