Week 2 Pre-op Assessment And Airway Mgmt Flashcards
(46 cards)
What is anesthesia?
Reversible, drug, induced depression of the central nervous system resulting in loss of response and perception of all external stimuli
What types of anesthesia are there?
- General
- Regional
- MAC
*multiple different methods to accomplish similar goals
What are the components of the anesthetic state
- unconsciousness
- amnesia
- analgesia
- immobility
*regional anesthesia breaks this definition slightly, but most components still apply
What are the common inhaled anesthetics?
- Isoflurane
- sevoflurane
- desflurane
- nitrous
How is inhaled anesthesia measured?
MAC: MInimun Alveolar Concentration
- stands for alveolar parietal pressures of a gas in 50% of humans do not respond to surgical stimulus
- dosing for inhaled anesthesia
- typically want at least 1 full MAC prior to incision
- measured at end-tidal concentration
What affects MAC values?
- will change depending on the pt
- infants will have the highest MAC requirement (even more than neonates)
- as people get older, MAC values decreases
- hair color is a factor (females with red hair have a higher MAC value)
what part of the nervous system do inhaled anesthestics work?
CNS
- spinal cord
- brain stem
- reticular activating system
- cerebral cortex
- GABA receptors subtype - A
What is the Meyer-Everton Rule?
-because inhalation agents act through the lipid-rich CNS cells, anesthetic potency increases with lipid solubility
Higher lipid content for inhaled anesthetic = higher potency
What are the MAC values of main inhaled anesthetics
Isoflurane: 1.2% is about 1 MAC
Sevoflurane: 2.0% is about 1 MAC
Desflurane: 6.6% is about 1 MAC
Nitrous: can’t get to 104%, can’t actually get to a full MAC
What is the purpose of the pre-op evaluation?
- Standard 1 from AANA
- CRNA is obligated to complete evaluation
- you are looking for pt factors that could alter your anesthetic plan and management
What is the purpose of the PAC clinic?
- Preanesthetic Assessment Clinic
- obtain medical history and physical exam
- promote patient teaching
- organize and coordinate meeting with other physician appointments relevant to surgery
- complete any other pre-op diagnostics
What are some key items to be looked at during chart review pre-op?
- med/surgical history
- social history
- anesthesia history (pt and family)
- MH, PONV
- medications/herbals
- labs
- tests
- stress test, echos
What is acceptable H & H in healthy pt without systemic disease?
- HGB: 7g/dL
- HCT: 25-30%
- evaluate and treat each pt individually for the etiology and duration of their anemia
When are some examples that a coagulation screen is indicated?
-pt on anticoagulation, signs of bleeding, esp with doing a spinal or epidural*
What are key points in patient interview?
- Name, bday, procedure, allergies, airway, NPO time
- quick head to toe run through of medical problems
- establish CRNA-patient relationship
What is the purpose of the pre-op assessment?
- establish trusting relationship
- modify parts of your plan to account for the pt risks associated with their co-morbidities
When does an airway assessment need to be done?
It needs to be done on every patient, for every procedure, regardless of the anesthetic plan
Why do we assess the airway?
-want to identify patients we may have trouble securing the airway ahead of time
What are you looking for during an upper airway assessment?
- Mallampati
- size of mouth opening/able to under bite
- condition of teeth and surrounding tissue
- size of mandible and neck
- thyromental distance
What is Cormack view?
Grading system commonly used to describe laryngeal view during direct laryngoscopy.
-most glottic opening can be see with grade 1
What are oral indicators that a pt may be a difficult airway?
- length of upper incisors: 2 front teeth long with be more difficult
- relation of maxillary and mandibular incisors during normal jaw closure: over bite/underbite
- relation of maxillary and mandibular incisors during voluntary protrusion of mandible: can’t do, limited mobility
- interincisor distance: less than 4cm or 2 finger widths will be more difficult
- visibility of uvula: difficult if not visible while pt sitting
- shape of palate: high, narrow=less room. Want to see flat and open
- compliance of mandibular space
What are neck indicators that a pt may be a difficult airway?
- thyromental distance: less than 3 fingerbreadths = difficult
- length/thickness of neck: short and thick will be difficult
- ROM of head and neck: pt cannot touch tip of chin to chest or unable to extend neck
What is Three Axis Theory/2 Curve Theory?
*need to look up
What is the ASA definition of “difficult to ventilate”?
When signs of inadequate ventilation can not be reversed by mask ventilation or the patient oxygen saturation can not be maintained about 90% with mask ventilation.