Intro to Anesthesia Flashcards
Types of anesthesia
General anesthesia
Monitored anesthesia Care “MAC”
Regional anesthesia
Local anesthesia
Ideal anesthetic Techniques
oOptimal patient safety
oPatient satisfaction
oExcellent operating condition for surgeon
oAllows rapid recovery
oAvoid postoperative side effects
oLow cost
oEarly transfer or discharge from PACU (cost)
Considerations that influence the choice of anesthetic/technique
oPatient safety oPatient comfort oPreference oCoexisting disease oSurgical site oPositioning oElective vs emergency airway oDuration of surgery oPatient age oRecovery time oPost anesthesia care unit discharge criteria
drug-induced depression of the CNS resulting in the loss of response to and perception of all external stimuli
SA continuum of sedation: a drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation
General anesthesia
Components of anesthetic
oUnconsciousness oAmnesia oAnalgesia oImmobility oAttenuation of autonomic response to noxious stimuli
Phases of General Anesthesia
Induction
Maintenance
Emergent
Candidate for total IV anesthetics
patient with severe refractory postop nasuea
Induction sequence
Room set up "SAM TIDE" - suction, airway, machine, tape, IV, drugs, equipment Apply monitors Position patient Baseline vitals Preoxygenate Administer induction agents (eyelid reflex) Mask ventilation \+/- NM blocking agent Airway instrumentation
ASA standard 5 minimum monitors include…
Pulse ox continuously - audible pulse and tone threshold along with clinical observaition and ABG analysis if needed
Ventilation - verification of trachea placement of artifical airway through auscultation, chest excursion, and confirmation of expired CO2 (3 breaths), capnography
EKG continuously, HR and BP at least every 5 minutes
Thermoregulation
NM (if NM blockade adminstered assess depth of blockade and degree of recovery)
Positioning
Pre-induction preoxygenation is doen in order to …
Denitrogenate patient’s FRC in order to increase safety margin for periods of apnea giving the provider more time before they desaturate
Methods for pre-induction pre-oxygenation
Breath 100% O2 via face mask with normal tidal volume for 3-5 min OR
Eight vital capacity breaths with 100% O2
oAdministering anesthetic drugs (inhaled or IV) to induce a state of anesthesia
oInducing a state of unconsciousness
Induction
Desirable properties for induction agents
Rapid and smooth onset of recovery
Analgesia
Minimal cardiac and respiratory depression
Antiemetic actions
Lack of toxicity or histamine release
Advantages pharmacokinets and pharmaceutics
Intravenous injection of an anesthetic to produce unconsciousness followed immediately by a neuromuscular blocking drug that produces a rapid onset of skeletal muscle paralysis
Rapid sequence induction
Situations that warrant a rapid sequence induction
Full stomach or risk of aspiration such as trauma patients, those with comorbidities such as DM and gastroparesis or achalasia
Main difference between standard induction and RSI
NO VENTILATION
Perform induction and ventilation, use standard induction without paralytics with this type of airway
Laryngeal mask airway (LMA)
Where does LMA sit
posterior pharynx and larynx and creates a seal around laryngeal opening, DOES NOT go past vocal cords
Most common method for inducing children in North America, scheduled for elective case
Inhalation induction
Agents used in inhalation induction
+/- 70% nitrous and 30% oxygen
Can have oxygen + nitrous +sevo
OR can have just sevo + oxygen
Steps for inhalation induction
Prime circuit Monitors (primarily pulse ox) Mask application Loss of consciousness Ventilation PIV placement Airway instrumentation (LMA/ETT) Verify placement
Maintenance goals
Maintain surgical anesthesia
Maintain physiological homeostasis
Monitoring is needed to ensure these goals are met
Maintenance phase provides
Unconsciousness, amnesia, analgesia, immobility, muscle relaxation, and control of system response to noxious stimuli
During maintenance phase the BP must be maintained
within 20% of baseline
Most sensitive indicator in anesthetic depth in inhalation anesthesia is…
pattern of respirations
Begins with administration of induction agents and ends with loss of consciousness
Pain response is altered but patient has same perception of pain
Stage I : analgesia
Begins with loss of consciousness and is a period of excitation and involuntary movements
Stage II: delirium
S/S of stage II : delirium
IRREGULAR respirations
Dilated pupils and divergent gaze
Tachycardia
Hypertension
What stages are seen for IV induction
Go from stage I straight to stage III skippping stage II
Begins with onset of regular breathing pattern and ends with loss of spontaneous respirations (for inhaltion induction)
Nonreactive to painful stimuli, deep sleep not subject to rousing
Stage III : Surgical anesthesia
Loss of lid reflex
Respirations regular and deeper than normal
Pupils react to light
Swallowing, retching, and vomiting reflexes disappear and reappear in that order
Respiratory response to skin incision decreased
Plane I of stage III
Starts when eyeballs become concentrically fixed
Regular respirations with decreased tidal volume
Respiratory response to skin incision disappears
Moderate loss of muscle tone
Reflex closure of vocal cords begins to disappear
Pupils unreliable
Plane 2 of stage III
Begins with decrease in intercostal muscle activity
Ends with intercostal activity absent and respirations is completely diaphragmatic
Diaphragmatic breathing > jerking movement
Pupils continue to dilate
Plane 3 of stage III
Begins with complete loss of intercostal activity
Ends with loss of spontaneous respiration
Pupils completely dilated
Nonresponsive to light
All muscle tone lost
Plane 4 of stage III
What planes are usually desired to keep the patient in
Plane 1 or plane 2 of stage 3
Respiratory paralysis - TOO DEEP
Cessation of respiration due to concentration of anesthetic agent
Ends with circulatory collapse and anesthesia should be lightened immediately
Stave IV : Overdosage
A transition process where a patient goes from general anesthesia to awake and spontaneously breathing
Emergence
Critical period of recovery from general anesthesia with the return of:
Consciousness
Neuromuscular conduction
Airway protective reflexes
A good indicator for adequate analgesia is
RR and opioid administration can de titrated according to rR
In emergence how should O2 be administered and why
100% oxygen for 5-10 minutes to prevent diffusion hypoxia from N2O
Deep extubation is performed while patient is in which stage and who is a good candidate
Stage III when under deep surgical anesthetic depth
Patient MUST be spontaneously breathing
Good for plastic surgery patients, hernia patients anyoen they do not want coughing or bucking the vent
Emergence phases
Stage III (deep anesthesia) to Stage II (excitation) then to stage I (awake)
What phase should NOT be extubated in
Stage II (excitement) WILL causes laryngospasm
How to assess what stage the patient is in in order to determine extubation
Assess respiratory pattern and look at pupils, if irregular they are in stage 2 and CANNOT be extubated
Suction patients mouth, if they hold their breath they are in stage 2
Patient purposefully follows commands and is extubated
Stage I - awake extubation
Awake extubation
Trachea is extubated only when the patient responds to simple commands and is breathing spontaneously
Awake extubation criteria
Patient conscious and responding to simple commands “open your eyes” “squeeze my hand”
If full stomach or high risk for aspiration, or if difficult intubation, extubate only when patient fully awake
Patient hemodynamically stable, normothermic, not having received massive amounts of fluid
Adequate spontaneous ventilation with TV > 6-8 mL/kg, rate >8
Adequate reversal of paralytics
Chosen when the presence of the ETT is to be avoided during emergence to prevent “bucking” and “straining”
Deep extuabtion
Examples: hernia repair, carotid endardectomy, tummy tuck, plastic surgeries
Indications for deep extubation
Avoid bucking, coughing, straining response to ETT
Avoid bronchospasm in a patient with a low risk for aspiration of gastric contents
Avoid CV response to ETT
Contraindications to deep extubation
Full stomach - severe GERD
Difficult intubation
Risk of regurgitation and/pr aspiration of gastric contents is a concern
Obesity
Does not describe the continuum of depth of sedation, rather it describes “a specific anesthesia service in which an anesthesiologist has been requested to participate in the car of a patient undergoing a diagnostic or therapeutic procedure”
Monitored Anesthesia Care
What do you need to know about a local anesthetic
Which drug Recommended dose Characteristic/knowledge Max dose Concentration With/without preservatives
Who is not a good candidate for local anethetic
Children Confused Uncooperative Unable to follow commands Patient with tremor/RLS Patients unable to lie down flat
A drug-induced state during which patients respond normally to verbal commands
Although cognitive function and physical coordination may be impaired, airway reflexes, and ventilator and CV functions are unaffected
Minimal sedation (anxiolysis)
A drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation.
No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained.
Reflex withdrawal from a painful stimulus is NOT considered a purposeful response.
Moderate Sedation/analgesia (“conscious sedation”)
A drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation.
The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.
Deep sedation/analgesia
Unarousable even with painful stimulus
Airway intervention often required
Spontaneous ventilation is frequently inadequate
CV function may be impaired
General anesthesia
