Monitoring Respiratory System

Question 1

What can we monitor for the respiratory system?

Answer 1

1. Respiratory rate and rhythm
   No info on quality of ventilation or oxygenation
2. Respiratory effort
   With equipment you can also:
   
   4. Assess adequacy of respiration
      Look at EtCO2
   5. Check or estimate blood gases

Question 2

How do we monitor respiratory system?

Answer 2

Look at chest of patient or reservoir bag
Listen to lung sounds
Capnography

Question 3

How can we monitor respiratory rate/rhythm

Answer 3

Look at chest of patient or reservoir bag
Listen to lung sounds
This won’t tell you efficiency of breathing - could be shallow breaths
Weight or positioning of patient can effect respiratory effort

Question 4

Why is listening to lung sounds important?

Answer 4

Useful to identify breath sounds
Provides information on quality of ventilation
Compare both sides of chest
Compare ventral and dorsal
Listen to inspiratory and expiratory sounds

Question 5

What is capnography?

Answer 5

Non-invasive continuous measurement of the partial pressure of carbon dioxide (CO2) in exhaled breath expressed as the CO2 concentration over time
VERY USEFUL
EtCO2
Dogs - 35-45 mmHg
Cats - 28-45 mmHg
ALWAYS USE WITH PULSE OXIMETRY

Question 6

Difference between capnograph and capnometry

Answer 6

Capnograph - Distinct waveform for each respiratory cycle (should look square)
Capnometry - Numerical value EtCO2

Question 7

What does Capnography tell us?

Answer 7

Tissue metabolism
○ CO2 metabolism
Perfusion
○ Blood flow carrying CO2 from tissue via the heart to the pulmonary capillaries
Ventilation
○ Carrying CO2 from alveoli in exhaled breath

Question 8

What are the three levels of information provided by capnography?

Answer 8

○ Level 1
Is patient breathing or not?
Respiration rate
○ Level 2
Expired and inspired CO2 levels
Need to know if sufficient amount of CO2 is being expired and not rebreathed
○ Level 3
Waveform
Is there an obstruction?
Allergic reaction?
Hyper/hypocapnia?
ET cuff inflation?

Question 9

Why do we need to look at CO2?

Answer 9

Exhaled CO2 levels give an easy way of assessing the state of the respiratory and cardiovascular system
Gives a reading that is close to that obtained by blood gas analysis (PaCO2)
Capnography gives virtually no false errors - highly reliable

Question 10

Hypercapnia

Answer 10

High CO2 in blood
>45mmHg
Normally caused by hypoventilation - not exhaling properly

Question 11

Hypocapnia

Answer 11

Low CO2 in blood
<35mmHg in dogs
<28mmHg in cats
Low if not breathing?

Question 12

Side stream system

Answer 12

Attach capnograph line to a connector between breathing system and ET tube
This thin capnograph line takes continuous sample of patients exhaled gas
Tells us:
○ Fraction of CO2 inspired
○ Respiratory rate
○ End tidal CO2 number (capnometry)
○ Wave form (capnograph)

Question 13

What does Blood Gas Analysis tell you?

Answer 13

• Evaluates CO2 and O2 levels in blood
  ○ Therefore shows efficiency of lungs moving O2 into blood and CO2 out
• Can measure:
  ○ PaCO2 - partial pressure of CO2 in blood
  ○ PaO2 - partial pressure of O2 in blood
  ○ Blood pH
  ○ Electrolytes
  ○ Lactate
  Arterial Blood analysis more useful for lung function
  Venous Blood analysis more useful for metabolic function
  Usually used to measure pH of blood to track progress of treatment of a patient