Ch.22 Complications of Inhalation Anesthesia and their Management

Question 1

How does hypothermia affect oxygenation

Answer 1

Shifts the oxygen haemoglobin dissociation curve to the left reducing the oxygen available to the tissues

Question 2

How does hypothermia affect drug dosage and clearance

Answer 2

MAC reduced 5-8% per 1*C drop in temp

Lower rate of clearance

Question 3

At what HR is action taken when horse under GA

Answer 3

18-20

Question 4

When is anticholinergic use advised

Answer 4

If bradycardia is accompanied by hypotension despite inotropic and fluid support
or
the arrhythmia is significant enough to cause fear of asystole

Question 5

Anticholenergics used to correct bradycardia

Answer 5

Atropine - slows GI most - Colic complication

Hyoscine-n-butylbromide

Glycopyrolate - used with xylazine - least effect on GI

Question 6

What must be discontinued before using anticholinergics

Answer 6

Sympathomimentic drugs like dobutamine, ephedrine, dopamine as can cause serious dysrhythmia

Question 7

What other drugs can be used to address bradycardia

Answer 7

Sympathomimmetics but will need a larger dose than for hypotension

Question 8

Addressing bradyarrythmia caused by hyperkalemia such as bladder rupture, UT obstruction, HYPP

Answer 8

IV Calcium, Sodium bicarbonate,
additional use of glucose, insulin, furosemide if not correcting

Question 9

What horses experience tacchyarrythmia under GA

Answer 9

Compromised horses who have not been stabilised with fluids prior to SX

Question 10

What dose of lidocaine can be used to address ventricular tachycardia

Answer 10

0.5-1mg/kg

Question 11

How do inhalant anaesthetics affect myocardial contractility

Answer 11

Dose dependent reduction
Vasodilation in compromised horses

Question 12

What is the target mean arterial blood pressure

Answer 12

70-90mmHg

Question 13

What does Dobutamine act on and what dose should it be administered

Answer 13

0.5 - 2ug/kg/min

Inotropic drug - mostly Beta 1 receptors
Beta 1 adrenergic agonist

Question 14

What should be used if hypotension is being caused by vasodilation such as in endotoxemia

Answer 14

Drugs with mixed alpha and beta effects eg ephedrine 0.05 - 0.1 mg/kg/iv
or
alpha only eg phenylephrine 1 - 2 ug/kg/iv

Question 15

Mean arterial pressure for foals

Answer 15

50-65mmHg

Question 16

How is adequacy of oxygenation measured

Answer 16

Arterial saturation SaO2
or
Arterial partial pressure of oxygen PaO2

Question 17

What can be used to calculate the oxygen content in clinical situations

Answer 17

SaO2 PaO2 and hemoglobin

(SaO2% x Haem (g/100ml) x 1.34) + (PaO2(mmHg) x 0.003)

Question 18

What should the Pa02 be

Answer 18

5 - 5 times the FiO2 in %
FiO2 - >90%
PaO2 400-500mmHg

Question 19

Positive end expiratory pressure bronchodilators

Answer 19

Beta 2 agonists albuterol, salbutamol

Question 20

An increase in of CO2 by 20mmHg will cause what change to pH

Answer 20

Reduce it by 0.1 unit

Question 21

Arterial cabin dioxide values of unseated horse

Answer 21

45 - 50 mmHg

Question 22

Ventilation parameters

Answer 22

1-15ml/kg per breath
4-8 breaths per minute
Peak inspiratory pressure of 20 - 30cm H20
Inspiratory time of 2 seconds

Question 23

Derangements in which electrolytes may contribute to hypotension

Answer 23

Sodium
Potassium
Calcium
Magnesium

Question 24

Conservative dosing for Calcium gluconate for hypotension

Answer 24

30mg/kg

Question 24

Conservative dosing for Calcium gluconate for hypotension

Answer 24

30mg/kg

Question 25

Dosing for Calcium chloride for hypotension

Answer 25

10mg/kg over 20mins

Question 26

Dose fro treating hypokalaemia

Answer 26

0.5mEq/kg/hr

Question 27

Normal urine output

Answer 27

0.5 ml/kg/hr