Anesthesia Support Part 1 Flashcards
(48 cards)
what are the benefits of endotracheal tubes?
- administration of O2 and inhaled anesthetics
- allows assisted ventilation (efficiently)
- prevents aspiration pneumonia
how do you make sure your ET tube is adequate size?
- check length before intubating
- use second tube to measure after intubation
- palpate trachea at thoracic inlet and feel tip of tube
what problems can occur if the ET tube is too long?
have a chance that it will go into the mainstem bronchi. if there is dead space, there is no gas exchange; so the patient could start rebreathing CO2 and inhaled anesthetic
warnings with intubation
- cuff over-inflation can cause tracheal leasions, stenosis or even rupture
- birds have complete tracheal rings
- laryngospasm is a problem in some species (cats, small ruminants, primates)
- caution with brachycephalic patients
- any upper airway pathology
birds have _______ tracheal rings
complete tracheal rings: a lot of times, vets won’t even inflate the cuff, or some people will use tubes that are uncuffed. can cause damage because the complete rings are present
what species have very sensitive larynx? what does this mean in terms of intubation technique?
cats, small ruminants, primates have very sensitive larynxes and will spasm as soon as you put the tube in.
- use local anesthetic! lidocaine will numb larynx to minimize the automatic closing that some species have
why do you need to be careful when intubating brachycephalic patients?
have an elongated soft palate and small tracheal size, need to be prepared to lift the soft palate and hold it up to see the airways to intubate.
- also have everted laryngeal saccules and narrowed nostrils
how do you inflate the cuff appropriately?
inflate cuff only until you don’t hear a leak up to 10-15cm H2O (SA) or 20-30 (LA). this is because if you have to do manual ventilation, that is the pressure you are going to start with
when you pressurize the machine to 20cm of H2O, do you want to hear a leak? why or why not?
yes, want to hear a leak- should cause a gas leak around ET tube to minimize damage to tracheal mucosa and wall. this means the cuff is creating mild gentle pressure into the tracheal mucosa.
if the cuff puts on too much pressure, the mucosa will not receive blood flow and will start dying and tear/rupture
what species get manual/digital intubation?
cattle, camels, elephants, walrus
what are consequences of over-inflating the cuff?
- can occlude the endotracheal tube itself
- distend tracheal wall and cause ischemia in the mucosa, tear may occur
- in tubes that are reused, get more pliant and the cuff might start moving around and actually occlude the tube
methods for intubation
- visual: using a laryngoscope
- blind intubation: rabbits, horses, mules, donkeys
- manual or digital intubation: put your hands in the mouth, feel the larynx and guide the endotracheal tube
- nasotracheal intubation
what types of stylets are there?
- soft stylet: feed stylet and then put tube thru it
- hard stylet: gives form to tube and then bypasses obstruction
what species get blind intubation?
rabbits, horses, mules, donkeys
how do you use a laryngoscope?
put laryngoscope at base of tongue; try not to touch the epiglottis! if you touch it back there, can cause trauma or inflammation
- sometimes soft palate needs to be lifted
- used for small ruminants, swine, dogs, cats, birds, reptiles
why can intubating cats be difficult?
their arytenoids are more vertical and completely close, so you have to wait for the cat to take a breath for them to open
- **why you should use lidocaine for all cats that you are going to intubate!
when do you manually ventilate your patient?
- hypoventilation
- hypoxemia (either high Co2 or low O2)
- to increase depth of inhaled anesthesia
- logistical reasons: not medical; may just be walking back and forth between 2 patients and want to ensure that they keep breathing
what are advantages of positive pressure ventilation?
- treat hypoventilation
- helps hypoxemia
- helps control anesthetic depth
- may free your hands for other tasks
what are disadvantages of positive pressure ventilation?
- complicated
- another thing to monitor
- equipment failure
- decreases CO and DO2: because putting positive pressure into chest. venous return relies on pressure in venous system to come back to heart and the + pressure prevents/decreases venous return
- decreases sympathetic tone: resp neurons in brain are in contact with ANS neurons in brainstem. when you start a ventilator, decreasing CO2 below threshold and the neurons switch off
- increase anesthetic depth
- transition at end of surgery
- potential airway damage
what are the functions of the rebreathing bag?
rebreathing bag is a ventilator
1. to breathe for your patient!! no patients should every die because of respiratory arrest because you have the means to breathe for them
what are 2 forms of assisted ventilation?
- manual (rebreathing bag)
- demand valve (O2 tank)
what is the demand valve?
horses/large animals: way to give breath for a horse in recovery stall: has a valve that pushes oxygen and then gives a breath of pure O2 thru the tube
what are the 2 forms of mechanical ventilation?
- pressure support: tell ventilator what pressure to reach
- volume support: tell ventilator what volume you want it to reach
both large and small animals have these
how do you set up the ventilator for pressure support?
- start ventilator until you see chest excursions
- set peak inspiratory pressure (PIP) to approx 10 cmH2O (SA) and 20-30 cmH2O (LA)
- adjust the inspiratory time as desired
- adjust the respiratory rate as desired
- watch for side effects
