1. Ventilation Parameters

Question 1

Why is respiratory ventilation in anesthesia important?

Answer 1

normal alveolar respo ventilation is done unconsciously to maintain arterial blood gas tension (particularly CO2)
Anes + drugs can interfere w/ unconscious mechanism. It is responsibility of people monitoring to recog changes and act accordingly

Question 2

What is the physiology of respiration

Answer 2

takes place in th emedulla oblongata or resp center
2 systems that control breathing are mechanical control and chemical ontrol

Question 3

What is mechanical control of the resp center?

Answer 3

nerve impulses that respond when the lungs are fully inflated and deflated
These are @ autonomic preset levels that prevent over-inflation and ensure proper amounts of exhalation
this system’s control is to maintain normal, rhythmic, resting breathing pattern

Question 4

What is chemical control of the resp center?

Answer 4

chemical receptors within blood vessels that monitor physical and chemical characteristics of the blood

Question 5

What are 3 characteristic that affect breathing processes?

Answer 5

CO2 content
blood pH
O2 content

Question 6

What happens if Co2 increases in the body?

Answer 6

Blood pH becomes more acidic -> triggers the resp center to inc rate and depths of breaths -> CO2 eliminated

Question 7

What happens if CO2 decreased in the body?

Answer 7

Blood pH becomes more basic -> triggers resp center to dec create and depth of breaths -> allows CO2 to increase
can also occur while bagging our patients under anes and can take awhile for animal to breath on its own due to low lvls of CO2

Question 8

What happens if O2 decreased in the body?

Answer 8

triggers resp center to inc rate and depth of breaths
NOTE: severe hypoxia can cause the resp center to fail due to neuron depression and may cause a dec or arrest of breathing

Question 9

What are 2 respiratory monitors for anesthesia?

Answer 9

1. capnography A) side stream sampling, B ) mainstream sampling
2. Pulse oximetry

Question 10

What is capnography?

Answer 10

the measurement of conc CO2 lvls in expired gas
the exp baseline should always be 0
upward slope indicates expiration
the highest value is the end-tidal CO2
Downward slope indicates inspiration
the results are displayed in millimetres of mercury (mmHg) or percent (%) CO2

Question 11

What are the normal values for a patient for capnography?

Answer 11

btw 35-45 mmHg
>45 mmHg = hypercapnia=hypoventilation
45-45 mmHg = eucapnia = normal
<35 mmHg=hypocapnia=hyperventilation

Question 12

What should we troubleshoot capnography when we have low ETCO2 for patient issues?

Answer 12

cardia arrest
dec in cardia output
hyperventilation
hypotension
air or pulmonary embolism
tidal volume too sm (collapsed lung/diaphragmatic hernia)

Question 13

What should we troubleshoot with capnography and low ETCO with monitoring issues?

Answer 13

sampling line disconnected or broken
endotracheal tube cuff deflated or leaking

Question 14

What do we need to troubleshoot with zero ETCO2 capnography lvls with patients and monitoring issues?

Answer 14

Patient: alive??, airway obstruction
Monitoring: endotracheal tube disconnect, esophageal intubation, obstruction in line or ET tube

Question 15

What do we need to trouble shoot with high ETCO2 capnography lvls with patient and monitoring issues?

Answer 15

Patient: hypoventilation, pneumothorax/lung Dz, hyperthermia/inc metabolism, pain, shivering
Monitor: pop-off valve closed, improper ventilation, valves sticking in rebreathe system

Question 16

What do we trouble shoot with baseline high ETCO2 capnography with patient and monitoring issues

Answer 16

Patient: rapid and shallow breaths
Monitor: large dead-space apparatus, exhausted CO2 absorbant, bain system incorrectly assembled

Question 17

What is side-stream sampling

Answer 17

extracts a sample of the resp gas btw the ET tube and the anes hose and diverts it back to a measuring chamber
PROs: small, lightweight, can be used in remote monitoring (MRI), can be used in non-anes’d patients
CONs: can prod falsely low ETCO2 in sm patients with high oxygen flow, 2-3s delay for results on monitor, sample tubes can be occluded with moisture/condensation build up
attachments can become lost or broken easily

Question 18

What is mainstream sampling and its pros/cons

Answer 18

Device that locally analyzes the respiratory gases btw the ET tube and anesthetic hoses but prods instant results
PROs: less moisture/condensation build up then side-stream. no disposable supplies to lose or break
CONs: heavy, prone to accidental disconnection, leaks, dropping damage, tendency to kink tubes

Question 19

What is pulse oximetry?

Answer 19

Measurement of haemoglobin O2 saturation
Non-invasive method of continuous measurement
abbreviated to Sp02 meaning the method of measuring saturated oxygen in bloodstream
Light-emitting diodes (LEDs) in red and infrared wavelengths penetrate the tissue and measure the light absorption spectra of the haemoglobin
will pick up HR
valuable info to detect earl dec oxygen saturation b4 resp or Cardiovasc failure occurs
greatly reduces the odds for anes related deaths

Question 20

What are Sp02 normal values

Answer 20

Normal % of Sp02 to sustain life and properly perfuse all the internal orgains is over 95%
Some will read lower around 93
Very important to detect hypoxia rather than an exact measurement reading
compare the color of mucous membranes is concerned

Question 21

Sp)2 placement cont’d

Answer 21

needs to be on an area for 30s b4 it can be assumed accurate
for quality control the HR needs to match the monitor reading
Can be placed on ear, tongue, pawpads, lip, prepuce/vulva
Readings affected by pigment of skin, amount of hair, movement of patient, peripheral vasoconstriction, thickness of tissue