Monitoring anesthesia

Question 1

4 areas of anesthesia monitoring:

Answer 1

¡ Neurological monitoring (reflexes)
¡ Cardiovascular monitoring
¡ Respiratory monitoring
¡ Anesthetic depth

Question 2

Methods of monitoring cardiovascular function: (6)

Answer 2

¡ visualization of the mucous membranes
¡ pulse palpation

¡ auscultation of the heart
¡ electrocardiography

¡ blood pressure assessment
¡ pulse oximetry

Question 3

what data do you seek via pulse palpation? (3)

Answer 3

¡ Pulse rate
¡ Pulse rhythm
¡ Vessel “tone”

The pulse should be full, regular and strong.

The “tone” of the artery gives an impression of degree of vasodilation.

Question 4

name the 2
commonly palpated arteries

Answer 4

The femoral or dorsal pedal arteries

Question 5

Pulse quality is an indicator of

Answer 5

stroke volume

Question 6

A pulse indicates what exactly

Answer 6

the pressure difference between systole and diastole

the smaller the difference the weaker the pulse
the bigger the difference the stronger the pulse

so a strong pulse does not automatically equal good pressure (ie. 75/25)

Question 7

pulse does not equal

Answer 7

heart rate

but these are strongly correlated

Question 8

intra arterial catheters favor what location

Answer 8

dorsal pedal artery

Question 9

large animal pulse can easily be checked

Answer 9

ie. transverse facial artery, facial artery

Question 10

sinoatrial node (sinus node) is located..?

Answer 10

in the wall of the right atrium

Question 11

the P wave signifies?

Answer 11

(both) atrial contraction

Question 12

the P-Q interval signifies…?

Answer 12

how long the electrical signal pauses in the atrioventricular node when its coming from the sinoatrial node in the right atrium on its way to the ventricles.

Question 13

what is hidden under the QRS complex

Answer 13

atrial relaxation

Question 14

the T wave signifies?

Answer 14

ventricular repolarization

there is never a situation in which one might have an ecg with qrs complex without t wave (except death).

Question 15

a narrow QRS complex signifies..?

Answer 15

the impulse is coming from the AV node alone (which takes over when the sinus node is not working)

Question 16

what happens when neither sinus nor AV nodes work?

Answer 16

purkinje fibers take over and cause ventricular contraction

Question 17

ecg monitoring, electrode placement on patient

Answer 17

Question 18

ecg measures

Answer 18

electrical activity of cardiac cells

you can have a beat on ecg but no pulse (ie. cardiac tamponade/compression) (pulseless electrical activity)!

Question 19

During anesthesia ECG is mainly used to

Answer 19

monitor the heart rate and rhythm

ECG monitors normally count the QRS complexes as a measurement of HR, but sometimes may also count some or all T waves.

The displayed HR should be double checked
regularly by comparison with auscultation and pulse palpation.

Question 20

each P wave has a QRS complex, each QRS complex has a T wave. what is this?

Answer 20

sinus rhythm

Question 21

respiratory sinus rhythm is normal for?
higher heart rate on inspiration, lower on expiration

Answer 21

dogs

but not cats

Question 22

sinus bradycardia may occur in what physiological state?

Answer 22

hypothermia

(also caused by alfa 2 agonists etc.)

Question 23

how do you know a lone P wave is a P wave?

Answer 23

there are no T waves without QRS complexes is how so in the image the lone wave must be a P wave (ecg depicts brady arrhythmia, AV block)

Question 24

blood pressure is

Answer 24

the force the blood applies against the blood vessel walls

Question 25

Arterial blood pressure Provides information regarding the adequacy of

Answer 25

blood flow to the patient’s tissue At a mean arterial blood pressure below 65 mmHg, organ and tissue perfusion is inadequate (hypotension).

Question 26

The systolic blood pressure is determined by a combination of (3)

Answer 26

peripheral vascular resistance, stroke volume, and intravascular volume diastolic blood pressure primarily arises from peripheral vascular resistance.

Question 27

diastolic blood pressure primarily arises from

Answer 27

peripheral vascular resistance

Question 28

which organs can auto regulate blood pressure in a certain range?

Answer 28

brain and kidneys

Question 29

Normal systolic blood pressure range for anesthetized dogs and cats is between

Answer 29

90 mmHg and 120 mmHg, diastolic blood pressure ranges between 55 mmHg and 90 mmHg

Question 30

Normal diastolic blood pressure range for anesthetized dogs and cats is between

Answer 30

between 55 mmHg and 90 mmHg

Question 31

Oscillometry =

Answer 31

Non-invasive method of blood pressure measurement, 1 measurement per 3 min max to allow the cuff and artery to rebound. Automatically determine arterial BP by measuring pressure oscillations in a cuff placed around an extremity ¡ Can determine all three arterial pressures

Question 32

A blood pressure cuff that is too wide will result in

Answer 32

underestimation of the pressure, while that which is too narrow will result in overestimation

Question 33

MAP minimum for adequate organ perfusion?

Answer 33

At a mean arterial blood pressure below 65 mmHg, organ and tissue perfusion is inadequate (hypotension).

Question 34

doppler technique for NIBP is still useful for what patients?

Answer 34

very small animals such as neonates

Question 35

‘gold standard’ for BP measurement

Answer 35

Invasive BP measurement A catheter is placed into an artery and then connected to a pressure transducer and monitor/recorder. Provides a continuous, beat to beat assessment of the patient’s blood pressure, is more accurate in hypotensive situations. Note: do not use too large a gauge to avoid arterial thrombosis.

Question 36

Oxygen saturation simply refers to the percentage of

Answer 36

available hemoglobin that carries oxygen.

Question 37

Describe Pulse oximeter waveform: normal low perfusion motion artifact

Answer 37

Question 38

Main 3 causes for rebreathing of CO2

Answer 38

faulty expiratory valve inadequate inspiratory flow/ too much dead space sodalime exhausted tms.

Question 39

patient related causes of elevated ETCO2

Answer 39

Question 40

patient related causes of decreased ETCO2

Answer 40

Question 41

Blood gas or acid-base analysis allows to evaluate..?

Answer 41

the partial pressure of important respiratory gases and pH of arterial blood

Question 42

Low pH with High PaCO2 =

Answer 42

Low pH: the patient is acidotic ¡ High PaCO2 - respiratory acidosis

Question 43

Low pH with Low HCO3 =

Answer 43

the patient is acidotic ¡ Low HCO3 – metabolic acidosis

Question 44

High pH with Low PaCO2 =

Answer 44

the patient is alkalotic Low PaCO2 – respiratory alkalosis

Question 45

High pH with High HCO3 =

Answer 45

the patient is alkalotic High HCO3 – metabolic alkalosis

Question 46

Corneal reflex during anesthesia

Answer 46

Corneal reflex: does not disappear until deep anesthesia. Should always be present. Not normally used.

Question 47

Nystagmus during anesthesia can indicate: (2)

Answer 47

usually indication of excitement and light anesthesia. However, dissociative anesthetics (e.g., Ketamine) cause nystagmus at moderate anesthetic depth. In horses, central stimulation induced by severe hypoxia or hypercapnia also causes this phenomenon, and should not be confused with light plane of anesthesia as animals are perishing!