GA: Induction - Exam 2 Flashcards
GA produces states of:
-hypnosis
-amnesia
-analgesia
-akinesia
-autonomic and sensory block
AGM check must happen Q _ hrs
24
Circuit on AGM must be checked Q
case
-before the case!
Circuit check steps:
1.take mask off and occlude circuit
2. press O2 flush to inflate bag
3.squeeze bag watching for increased pressure in circuit
-this helps ensure no holes/leaks if +pressure is needed
Suction should be:
-at HOB
-ON!
T/F Preox reduces alveolar N2O
false,
reduces alveolar N2
During preox should I be concerned if SpO2 isn’t at 100%?
no
-also SpO2 100% doesn’t mean their alveolar conc is >90%*
Normal CMRO2
250 mL/min
Normal FRC
2500mL
-<500mL of it is O2 when on RA, so pt desats after 1-2min
- ~2000mL+ is O2 after preox, so pt can last ~8min no desat
-N2 normally takes up ~95% of this on RA
Goal of preox:
-EtO2 of 90%+ means >2000mL is O2 in FRC
-EtN2 is ~5%
FRC formula
FRC=ERV+RV
expiratory reserve volume + residual volume
VC formula
VC=Vt + IRV + ERV
tidal vol + inspiratory reserve volume + expiratory reserve volume
Preox methods
-best is 3-5min at 5+L =PaO2~392
can also do 8 VC breaths at 10+L = PaO2~370
or 4 VC breaths at 20L gets close
Pts with reduced FRC:
obese
pregnant
infants
Most likely reason for not achieving proper PaO2 during preox?
loose mask
Ppl who are hard to get good seal for BMV:
beards
no teeth
sunken cheek
NGT
wrong size
How to tell you have good mask seal?
-good EtCO2 waveform
-reservoir bag moves
Pts who may need LESS induction med
-old
-liver/renal fail
-hypovolemic
-shock
-adjuvant drugs
DOC for induction
Prop
Propofol is a sterically _ _
hindered phenol?
-water insoluble so formulated w lipid emulsion of soybean oil, glycerOL, and egg lecithin
Prop MOA
GABA mimetic, NMDA antagonist
Pros Propofol
-fast on, fast off
-ANTIPRURETIC
-BRONCHODILATOR (reduces airway RESISTANCE)
-ANTICONVULSANT (reduces CMRO2)
-ANTIEMETIC PROPERTIES -less PONV
Cons Propofol
-greatest negative inotropic effect
-largest decrease in SVR
-burns
-give within 6hr drawing up
-generic form causes allergies from sulfites
Etomidate indications
-CV instability
-frail
-trauma
Pros Eomidate
-CV stability, slight dec in SVR
-fast on and off
-REDUCES ICP, CBF, AND CMRO2; anticonvulsant
-minimal resp depress
Cons Etomidate
-myoclonus in 50-80%(can give benzo/opioid to help but if they need etom maybe shouldn’t have those)
-burns
-INCREASES PONV
-cortical adrenal suppression (don’t redose if needing more)
Ketamine indications:
-hypotensive
-likely to be hypotensive (hypovolemic, septic, CV compromise, hemorrhage)
-severe asthmatics
MOA Ketamine
NMDA receptor antagonist
-effect on areas centrally and preipherally
Pts who should avoid Ketamine:
-HTN, angina, CHF, Pulm HTN, ICP increased, increased IOP, psych dx, PHEOCHROMOCYTOMA
Pros Ketamine
-dissociative state + nystagmus often
-no vasodilation (decreases nitric oxide)
-+inotrope
-increased <3 demand of O2
-BRONCHODILATOR
-MAINTAIN AIRWAY /RESP REFLEXES
-many routes
Cons Ketamine
-dissoaciative state-hallucinations, emerge delirium
- increases CMRO2, CBF, ICP
-increases HTN (ischemia, R sd HF -pulm HTN)
-secretions
-messes w/ BIS monitor
Versed for induction tidbits:
-BP doesnt change much
-less resp depress
-decreases CMRO2 and CBF
Versed induction dose:
-0.2-0.25mg/kg
Should I give more propofol to old pt after 1.5 min if nothing has happened?
no, their circulation time is longer usually
Prep for induction:
-monitors, precordial, PNS if necessary, NIBP auto
-equipment (LMA, mask, ETT, laryngoscope, stylet, syringe, tongue blade etc) + extra + OPA at HOB
-drugs at HOB
-SUCTION ON at HOB
-armboard -brach plexus injury poss if not
-metal circuit fingers at HOB
-table at elbow ht
-preox
-APL OPEN until pt apneic
-MASK FIT +HEADSTRAP
BMV Induction steps:
-IV open wide
- give drug over 15 sec
-recheck IV, slow fluids
-watch pt -look for long deep breaths (prop yawn)
-check LOC (are you warm/lash reflex)
-bag pt, tape eyes
-insert device if needed
-turn on agent
When bagging avoid PIP over _cmH20 for risk of insufflation
20cmH2O
When BMV and pt is breathing a little what can I do?
-let them initiate breath, then assist w bag
Can gauge level of anesthesia when masking by:
-amount of Vt pt takes on own
ETT Induction steps:
-narcotic(blunts SNS response to tube)
-prop (give lido 20-30mg 1st or mixed in)
-induction drug
-check LOC
-be able to bag pt for 12 breaths, tape eyes(feel bag move, EtCo2 wave)
-give muscle relaxant and turn on agent of choice while waiting
-check onset of relaxant with pns (pt flaccid)
-laryngoscope + tube
-laryngoscope in basin, GLOVE OFF, inflate cuff
-attach pt to circuit
-ensure ETT placement (chest rise, EtCO2, BS)
-turn on agent, adjust vent, tape ETT
Inhalation induction steps:
-often w peds
-turn up Sevo conc quickly(like 8%) or go up slowly if airway reactive
-breathe pt down
-IV in
-continue with IA or give IV induction drugs
-control breathing
-intubate
Indications for RSI due to high risk regurg:
-full stomach
-obese
-pregnant
-some DM
-bowel obstruction*
-appendectomy*
-hiatal hernia + reflux
-concurrent opioids*
-trauma
-ASA IV or V
-pain /stress
-decreased LOC
3 goals of RSI
-prevent hypoxia
-minimize time in stage 2 (risk of laryngospasm, pain, CV instability, combative, aspiration)**
-use methods to decrease risk of aspiration
Most often times for pt to aspirate
-INDUCTION
-laryngoscopy
-during/after emergence
Sellick Maneuver
-cricoid pressure against C6 area of cartilage
-20N before pt asleep
-30N after loss of consciousness
Sellick Maneuver complications:
-cartilage fx
-airway obstruction
-esoph RUPTURE (from fetching if 30N on awake pt)
-C spine/ laryngeal injury (if 40N)
-decrease LES tone
What is the primary barrier to the gastroesophageal reflex?
LES
-2-5cm long
-traverses diaphragm
If the angle of a pt’s stomach is _ they will have less reflux than if the angle was _(seen in pregnant or obese pts)
higher
smaller
Name the intrinsic reflexes the body has to protect against aspiration?
-LARYNGOSPASM
-apnea
-spasmodic panting
-cough
-expiration
LES pressure is normally _ than the gastric pressure
greater than
LES pressure - gastric pressure =
barrier pressure
GERD happens when barrier pressure _.
decreases
Reflux happens when either LES pressure _ or gastric pressure _
decreases
increases
The diaphragmic crura is a protective mechanism that _ at the lower esophagus to prevent reflux
tightens
Mendelson syndrome is a form of chemical pneumonitis that can occur after gastric contents with pH < _and volumes >_mL /kg (25mL in adults) is aspirated
pH<2.5
volumes > 0.4mL/kg (25mL)
Pt is aspirating what can be done?
-turn head to sd
-trend bed to more easily suction contents/keep away from lower airway
-O2, CPAP 12-14 mmHG or intubate + vent
-Beta 2 agonist inhaler to treat following bronchospasm
-no irrigation, steroids, or abx
Signs of significant aspiration happen w/in 2hrs and include:
-bronchospasm
-10% drop in baseline SpO2*
-A-A gradient 300mmHg on 100% O2*
-CXR shows infiltrates/atelectasis (RLL usually)
-if pt on vent >24hr after this happens likely will get ARDS
-damage to lungs can cause alveolar+interstitial edema and hyaline membrane scarring*
NGT what do we do?
-keep in and must keep hooked to suction
-suction and remove to prevent LES from being propped open
-suction and pull back to midesophageal level(30cm from nare) to allow LES tone to increase and prevent pressure during induction
Meds that can be given to prevent aspiration
-metoglopramide
-cimetidine/ranitidine
-Bicitra
-PPI
-Glycopyrolate and Atropine
Metoclopramide:
-a procainamide derivative
-takes 20-30 mins before volume is reduced*
-increases LES tone in 1-3 min via IV*
-CI in bowel obstruction/appendectomy and PD or depression (EPS)**-dopamine antagonist
-opioids blunt this bc they delay gastric emptying*
Cimetidine/Ranitidine:
-competitive H2 blocker
-lowers basal acid secretion
-takes 20-30 mins to work
Sodium Citrate/Bicitra
-nonparticulate antacid
-increases pH on contact
-good bc if aspirated won’t cause chem pneumonitis unlike particulate alkalis
-INCREASES LES tone and INCREASES barrier pressure
Preventing Regurg/Aspiration
-PPI
-block H+ and K+/ATP enzyme systems on secretory surface of parietal cells
-decreases stomach acid volume and increases pH
-takes 1 day to work, effective for 3 days
Glycoprolate + Atropine
-anticholinergics
-inhibit vagally mediated acid production, increasing pH
-Glyco decreases LES tone, atropine doesn’t
If GERD happens with sellick maneuver, regurgitation into the pharynx _ happen.
won’t
NPO supine pt maximum intragastric pressure is _mmHg
25
Gastric distention with 750mL can cause intragastric pressure to be _mmHg
35
_N of cricoid pressure can prevent regurg from _N of gastric pressure
30N
40N
20N of pressure can let regurg still happen but _ will not
rupture
Sellick maneuver cons
-makes visualizing harder by displacing larynx laterally
-can occlude airway
-can decrease LES tone
-can promote gastric reflux
T/F sellick maneuver required for RSI
true
Drugs that increase LES tone and barrier pressure
-alpha agonists, antacids, antiemetics, cholinergics, edrophonium, histamine, metoclopramide, metoprolol, neostigmine, pancurium, sux(raisesGASTRIC pressure)
Drugs that decrease LES tone and barrier pressure
-Beta agonists, dopamine, glycopyrolate, IA, NTG, opioids, nipride, thiopental
Drugs that don’t affect LES tone
cimetidine, ranitidine, propranolol, vecuronium
Which drugs has no effect on barrier pressure but lowers both esophageal and gastric pressure?
prop
If pt can’t have sux for RSI, give _ at _ its dose
rocuronium
DOUBLE
Reasons to not give sux for RSI
-burn
-crush injury
-hyperK+
T/F Pt with hx of diff airway or airway looks diff should have RSI
HELL NAW
-do an awake intubation with FIS for diff airway
-if BMV diff but intubation doesnt seem to be,go for RSI
T/F If a cuffed ETT is in place, pt is safe from aspiration
false
-microaspiration can happen
_mL is considered a severe pulmonary aspiration
50mL
_mL/kg is considered the avg lethal dose of gastric fluid
1
Pts at risk for increased gastric volume, pressure, and acidity
-<6hr NPO
-gastric insufflation (mask vented pt)
-acid hypersecretion (hypoglycemia, etoh, increased gastrin)
Pts with delayed gastric emptying
-intestinal obstruction
-drugs (opioids, anticholinergics)
-preg
-obese
-DM (gastroparesis), PUD, trauma
-SNS stim (pain, stress, anxiety)
Pts with decreased LES tone
-preg
-GERD
-hiatal hernia
-laryngoscopy
-cric pressure
Pt risk factors for decreased UES tone + loss of protective reflexes
-GA+sedation
-AMS or head trauma
-CNS depressants
-CVA/TIA
-neuro diseases (MS, GBS, cerebral palsy, PD)
-NM diseases (MD, MG)
My pt aspirated and is on a vent, now what?
-use PEEP to improve FRC and improve VQ mismatch
-low FiO2 as possible to keep PaO2>60-70
-if that isn’t good enough, treat like ARDS (low Vt -6mL/kg and permissive hypercapnia)
-ADD PEEP
-LOW FiO2 - want PaO2 ~60-70
RSI steps:
-suction ON at HOB**
-preox**
-have someone start sellick maneuver(if vomiting occurs, release to pvn rupture)
-pretreat with subclinical dose of NDMR **
-give full calc dose of prop or agent of choice**
-give full dose of sux (1.5mg/kg)**
-DO NOT VENTILATE**
-give sux 60 sec then laryngoscopy and intubate**
-inflate cuff THEN confirm placement**
-release cric pressure AFTER placement confirmed**
-secure ETT, place OGT
T/F should aim for moderate doses for RSI
HELL NAW CRANK DAT SHIT
-high end
Why pretreat RSI with NDMR?
-usually sux is given with RSI!!!
-BUUTTTTTT sux causes fasciculations that increase gastric pressure and aspiration risk, this helps prevent that
T/F For RSI give muscle relaxants then perform sellick maneuver
false, sellick 1st, MR next
T/F no oxygenation without ventilation
false,
can pass nasopharyngeal cath into airway and give O2 that way
-works bc there is a 240mL/min negative pressure gradient caused by difference in O2 diffusion in and CO2 diffusion out
RSI dose of Rocif can’t use sux
1.0-1.2mg/kg
RSI dose for Vec
0.3mg/kg
