Test 1: 9 breathing systems Flashcards
purpose of breathing system
O2 in
deliver anesthetic gas
remove CO2
control ventilation
rebreathing system has — flow of gas through the system and does what to CO2
unidirection
absorbs
non rebreathing system have — valves and does what to CO2
No unidirectional valves
No CO2 absorbent- relys on high FGF to remove CO2
steps of rebreathing system
what controls full, partial or non rebreathing system
amount of O2 flow and the amount of gas reused
at O2= metabolic demand= full rebreathing, no waste
at O2> metabolic demand, low flow causes less waste
if very high flow rate- non rebreathing system (fan in face)
why do you use low FGF
less waste
less environmental contamination
preserves heat
cons of using low FGF
decreased anesthetic gas delivery (at same vaporizer setting)
slower changes in anesthetic concentration
fresh gas inlet in circle system leads to a one way valve that opens during —
inspiration
allows air in but during exhale is closed so no air goes backwards
what is the dead space in the breathing circuit tubing?
the area when inhale and exhale mix (Y piece or before the purple tube)
how to measure reservoir bag
1L per 10 kg
(5-10 x TV (10-20 ml/kg))
in circle system that expiratory one way valve leads to the —
reservoir bag
valve is open during exhale and closed during inhale (allows unidirectional flow only)
when to open or close the pop off valve
always open during spontaneous ventilation (if closed can lead to pneumothorax!)
close to manually breathe for patient
how to rid inhalant safely from circle system
vented outside
absorbed by F-air canister (scabvenging system)
carbon dioxide absorbers work by
change color(white to pink) and become hard → need to replace
base (absorbent) neutralizes acid (CO2) →H20 + carbonate + heat
types of CO2 absorbents
soda lime - most common
baralyme (barium lime)
amsorb (calcium hydroxide lime- nexest)
non rebreathing system rely on — to flush CO2 from circuit
↑ fresh gas flow rates (130-300 ml/kg/min)
NO one way valves
NO CO2 absorbent
when to use non-rebreathing system
small patients < 10 kg
used to decrease dead space and decrease work of breathing
how to check for leak in system
- close the pop-off valve
- occlude the end of the hose
- pressurize to 20 cm H20
- turn off O2 flow
- if holds for 10 sec good
- if leaks, quantify leak by turning ocygen flowmeter up until leak stops (< 300 ml/min ok)
- OPEN THE POP-OFF
why use supraglottic airway
- simpler and faster to place
- less sedation needed to place
- does not need laryngoscope
- does not enter the larynx or trachea
- Must be properly fitted in order to seal well
- allow to positive pressure ventilation
- V-gels are vet species specific
ET tubes are used to
- provide patent airway
- allow for positive pressure ventilation (give breaths)
- protect lungs from aspiration
- prevent contamination of the work environment
what size ET tube
biggest that will fit
length should not extend beyond the throacic inlet (ventilate both lungs)
what ET tube can not be kinked closed
guarded- metal prevents closing of tube no matter what position
how to check pilot balloon on ET tube
someone manually ventilates to 20 cmH20
while someone else smells and listens for leaking
how to intubate a horse
blind
bite block, tongue moved, slid right in
how to intubate cow
palpation
can stick your hand in and feel for larynx
— aid in visulatization of the oropharynx during intubation
laryngoscope
miller- straight
macintosh- curved
if you can’t see laynx what can be used to help intube
wire guided technique
place wire and then slide tube over wire
when to use nasotacheal intubation
need to operate in mouth
- provide supplemental O2 to awake or sedated animals
- inducing foals and calves
use lots of lubricant to prevent damage
extubate carefully: slowly and deliberately
retrograde intubation
go from trachea out to mouth, then pass ET tube over guide wire
tracheostomy
when you can’t intube any other way
when pt needs patent airway after surgery
lots of complications- infection, hemorrhage, aspiration
how to confirm placement of ET tube
- ETCO2- capnography
- listen when you give breath
- movement of reservoir bag when patient is breathing
- palpate for “one tube”
- air felt out of tube on exhalation
