Complications---Anesthesia

Question 1

What are some common complications we face during anesthesia?

Answer 1

• Hypoventilation and apnoea **
• Hyperventilation
• Bradycardia **
• Tachycardia **
• Hypotension **
• Hypertension

Question 2

Is every complication an emergency?

Answer 2

NO

Question 3

If there’s an emergency, say ongoing tachycardia, are you going to stand there with the clipboard and anesthesia record like a klutz and write it down or are you going to move your behind and take care of the emergency and THEN document it when things are stable?

Answer 3

The latter.

Don’t be a klutz.

Question 4

Will you always see low RR when patient is hypoventilating?

Answer 4

NO so be careful.
Could be low end tidal. Also, check blood gas.
PaCO2 will be 45 mmHg

Question 5

If respiration rate is zero, is this still hypoventilation?

Answer 5

Nope—APNEA.

Question 6

IF NOTICE hypoventilation, what’s the first thing you do?

Answer 6

Check plane of anesthesia. check jaw tone, reflexes.

Question 7

What is the eye position in decent plane of anesthesia in small animals?

Answer 7

Ventromedial, if plane is too deep, eyes go central.

Question 8

If you have hypotension and the eyes are positioned centrally, what does this mean?

Answer 8

Means your plane of anesthesia is too deep.

Question 9

If all the parameters are normal like jaw tone etc for anesthesia but there’s still hypotension and hypoventilation, what does this tell you about your plane of anesthesia?

Answer 9

Too deep.

Question 10

The most common cause of hypoventilation while under anesthesia…

Answer 10

Drug induced respiratory depression (e.g. propofol, etomidate, ketamine, …)

Question 11

Remember the normal range of CO2…

Answer 11

35-45 mmHg

Question 12

Do you treat hypoventilation?

Answer 12

1) try to reduce plane of anesthesia
2) intubate patient just in case
3) give them O2 with a face mask
4) Mechanical ventilation if CO2 gets too high
5) Warm up patient if they become hypothermic (bc that contributes to hypoventilation)

Question 13

The term to describe regular mechanical ventilation:

Answer 13

IPPV – intermi\ent posi,ve pressure ventilaton

Question 14

What does the pressure gauge look like during spontaneous breathing vs mechanical breathing??

Answer 14

Spontaneous:
When patient inhales, pressure goes negative then back to 0. THere’s no positive pressure in the thorax in spontaneous breathing.

Mechanical:
The opposite occurs. The pressure gauge goes positive and then back to 0.

Question 15

What happens if we’re trying to mechanically ventilate that has collapsed alveoli?

Answer 15

Use PEEP-positive end-expiratory
pressure. It leaves some positive pressure behind and never quite reaches 0 so the alveoli don’t completely collapse that way you don’t have to force them open again with every breath.

Question 16

What is PIP – peak inspiratory pressure?

Answer 16

The highest pressure you go up to. for normal healthy patient, don’t go over 10-15 but 20 can be MAX.
Look at capnograph and all we want for them is to be in the normal range for normal CO2.

Question 17

For the IPPV machine, what should the Inspiratory:Expiratory ration be?

Answer 17

–I: E ratio: 1:2

Question 18

Perks of using IPPV:

Answer 18

– Improved oxygenation (nice SpO2, PaO20 values)
– Reduction of hypercapnia (improved ventilation)
– “free hands

Question 19

Downsides of using IPPV:

Answer 19

• Decreases you CO. remember, you no longer have the negative pressure in the thorax so the positive pressure puts pressure on the big vessels which dec venous return, dec cardiac output, dec BP as well. So, lower CO and lower BP.
• potential barotrauma. It’s important to stick to the max pressures otherwise you can rupture lungs.

Question 20

What happens if you have apnea right after you induce anesthesia?

Answer 20

Don’t panic. It’s normal but don’t wait to ventilate them like 2-4 times a minute then they’ll do it on their own.

Question 21

What happens if you have apnea DURING anesthesia?

Answer 21

Panic. This is an emergency. some causes to consider:

• Anesthetic plane to deep
• Equipment failure (pop-off valve closed so don’t forget to keep it open!!, ventilator stopped)
• Hypothermia-must be really severe to induce apnea
• Reflex apnea secondary to visceral traction–quite common. Can even see this in eye procedures due to an ocular reflex as well.

Question 22

Some less common causes of APNEA:

Answer 22

• Extreme hypercarbia/hypoxemia
• CNS disease (brain edema)
• Metabolic alkalosis
• Open thorax—let’s just say there’s a hernia that you missed
• NMBA

Question 23

You have a reading of PaCO2< 35mmHg

what does this tell you?

Answer 23

Patient is hyperventilating

Question 24

If BP and HR and RR going up, stiff jaw tone, what does this tell you about your plane of anesthesia?

Answer 24

Too low.

Question 25

What if you’re on low flow, and you go from 1.5% ISO to 2% to increase the plane of anesthesia? what do you to do Fresh gas flow?

Answer 25

Increase it as well!

Question 26

What if your soda lime is exhausted?

Answer 26

It will cause hypoventilation bec of high CO2.

Question 27

Small dogs have a tendency to hyperventilate or hypoventilate?

Answer 27

HYPERventilate

Question 28

Some reasons for hypoventilation:

Answer 28

Severe hypothermia
Drug induced like propofol, etomidate, ketamine, etc.
Positioning
Deep plane of anesthesia 
NMBA (musculoskeletal paralysis)