adc. princip: MAC (monitored anesthesia care) Flashcards
- what is MAC (monitored anesthesia care)?
2. How often is anesthesia used in these cases (%)
- anesthesia given during a planned procedure such as endoscopy, MRI, neuro radiology (specials), oncology, cath lab etc.
- 6-12 percent of cases
what is the objective of MAC
- providde comfort and safety to the patient under local anesthesia
- monitor VS and provide anxiolysis, analgesia, amesia and sedation without compromising cardiorespiratory function or delaying recovery
- consciuos sedation using sedatives, tranquilizers, anagesia, and subanesthetic conc. of inhaled agents alone or incombination to support local or regional anesthesia
- sedation to facilitate local or regional anesthesia by blunting sensations such as pressure, movement, traction, position change or awareness of noise and activity.
what are JCAHOs 4 levels of sedation? (and give details differentiating each one).
- minimal sedation (anxiolysis) with sedatives
- moderate sedation/ analgesia (consciuos sedation): patient breathes on own, follows commands
- deep sedation/analgesia: airwy support or oral airway
- anesthesia: patient does not breathe on his/her own
what procedures are frequently done under sedation or local/sedation?
- arthroscopy 9. cystoscopy
- invitro fertilization 10. gastro-intestin endoscopy
- blepharoplasty 11.d&c
- cataract extraction 12. rhinoplasty
- dental extractions 13. breast and other biopsies
- upper extremity surgery 14. bronchoscopy
- rhytidectomy 15. insertion of lines and shunts
- superficial skin proc.
benzodiazepines facts:
- ues/ desired effect
- titration
- considerations (patient info)
- used in conjunction with what type adjuncts
- respiratory side effects
- antagonist (and dose)
benzos:
1. uses: anxiolysis, amnesia, sedation
2. dose: careful titration (0.5-2 mg iv)
3. considerations: age and medical hx (prolonged in elderly, renal
4. usually given with narcotic for comfort
6. resp s/e: resp drpression, hypoxemia, hypercarbia
7. antagonized by romazicon (flumazenil) 0.5 mg IV
8. use cautiously in outpatients
there is more chance for respiratory issues with sedation cases, what should you use to avert as many issues as possible?
precordial stethoscope
why doesnt local sedation work well in infected tissue?
because the LAs become ionized and cannot enter the nerve membrane (only the non ionized portion can cross).
what is one issue with the elderly and sedation medication you have to be aware of (as far as dose and onset)?
older persons have slower medication onset d/t decreased cardiac output, so it is easy to overdose them while trying to reach the desired effect.
ketamine facts:
- respiratory
- desired effects, uses?
- pre-treat for what?
- works well on ____ population:
- maintains respiratory effeciency even if used with Benzos
- dose=.25-.5 mg/kg for sedation, amnesia and analgesia during local anesthetic injection
- pre treat with glucopyrolate (d/t increased secretions from keta.)
- works well on elderly population
N2O facts:
- what is the max dose of nitrous, why?
- what are some of the pros of N2O
- what can you use nitrous to supplement
- what age and type patient should nitrous be avoided in?
- what should be available if using nitrous
- dose of N2O is 30-50% (d/t fact it is a mix with oxygen and you can go no less than 30% o2).
- good for avoiding deep sedation and its potential of excitement, resp depression and aspiration
- good supplement to versed or propofol
- avoid in elderly or debilitated patients
- only use if scavenging available
IV sedative/hypnotics:
- # 1 drug used for this? why?
- what “type” doses would be used?
- doses, and how administered?
- use caution in what patient populations (including ASA status)
- propofol is the most widely used d/t short duration (faster recovery than with versed), rapid onset and minmal side effects.
- sub hypnotic doses
- bolus doses of 200-500mcg/kg (on pump) followed by continuous infusion
- use cautionsly with elderly, debilitated and greater than ASA 3
dexmedetomidine facts:
- class of drug
- attributes of drug effects
- chemical action of drug:
- loading dose; infusion dose
dexmedetomidine: precedex
1. class: sedative and anxiolytic
2. parallels REM sleep, has no resp depression, easily arousable
3. stimulates post symaptic alpha adrenergic receptors (inhibits adenylate cyclase which reduces nor epi in the CNS)
4. 3 mcg/kg loading dose over 10 min; 2 mcg/kg/hr infusion
what drug is good adjunct with spinal (sub arachnoid anesthesia)
propofol
what are 2 biggest adverse side effects of propofol?
- apnea
2. hypotension
- what is the cause of a large percentage of anesthesia accidents?
- what % were preventable
- brain injury or death d/t inadequate ventilation
2. 69% were preventable with better monitoring
what is global monitoring?
global monitoring is verbal comunication with patient,
tactile stimulation,
squeezing hand,
feeling air exchange,
watching chest rise
respiratory monitoring:
- what should you always have during a sedation case (on the patient and at your reach)
- what are the 4 respiratory monitoring system/ methods that must be utilized (2 manual and 2 computerized)
- always use supplemental o2 & always have ambu, airway equipment, suction available
- clinical observation, precordial stethoscope, pulse oximetry, ETco2
- name most basic but crucial respiratory monitor during sedation cases:
- what should you observe?
- what signs are late (almost too late)?
- what human error causes alot of problems with sedation cases
- clinical observation (eyes, ears, hands)
- respiratory rate, pattern, tidal volume
hypoventilation, obstruction, regurgitation, feel air exchange with your hand, visualize chest movement, listen to breath sounds,
observe color, - vital sign changes are late
- poor observation (d/t chatting, texting etc.).
- what is one of the best manual monitors of airway in sedation cases?
- pros
- cons
- precordial- (monitor of choice)-ALWAYS use with sedation cases!!
- pros_ can detect subtle signs (ie laryngo spasm, airway obstruction) (place on sternal notch to listen)
- cons_cannot detect adequate tidal volumes
- what is a mandatory and reliable (electronic) monitor in sedation cases?
- why use it?
- should be used on everyone, but who is at high risk?
- what is the correlation between sao2 and pao2? what is optimal pao2?
- pulse oximetry
- warns of desaturation with visual and audible tone
- persons at risk of hypoxemia in obese, old and young, lithotimy positoin, decubitus position
- sao2 of 90%= pao2 of 60 mmHg. optimal pao2 is 105 mmHg
- What is computer gas monitoring that should always be used (if possible)?
- what does it do?
- what are normal values?
- if you dont have a canula that connects what can you do?
- ETCO2 has become a standard in monitoring since 2011
- monitors exhaled co2 (and inhaled as well), shows capnographic wave form and numerical
- normal values=35-45 in normal, inhaled should be zero.
- put it near their mouth or connect it into the canula with a needle
- what othe monitoring should be done in sedation cases besides respiratory monitoring?
- what does that entail (3 electronic and 1 manual)? give examples.
- circulatory monitoring
- it involves:
a) visual/tactile; (observe skin color, temp and cap refill)
b) BP ; (manual or NIBP)
c) ECG; (to detect rate, rhythm and changes)
d) pulse ox (plethesmography gives heart rate audibly)
alterations in circulation in sedation patient:
1- causes of CV stimulation
2- causes of CV depression
- stimulation: d/t patient anxiety, inadequate analgesia, medications (ketamine, epinephrine, cocaine)
- depression: d/t direct myocardial depression, periphrial vasodilation, hypoxia
- What do you need for MAC outside the OR?
2. what are some of the issues with mac outside the OR?
- mac outside the OR needs: pulse ox, nibp, ecg, stethoscope, full oxygen tank, ambu bag, suction, airway equipment (oral airway, laryngoscope, blade, tubes & LMA). Ideally you want anesthesia gas machine & iv sedation pumps available as well.
- outside the OR you may not have qualified personell to help and may not have an anesthesia gas machine
- Type of anesthesia in CT
2. potential issues
- you may do sedation or general aesthesia in CT:
- problems:
a) poor access to patient
b) poor patient visability
c) ionizing radiation exposure
d) contrast allergies (have anaphylaxis med ready (benadryl 1 mg/kg & epi 1cc of 1:1000)
- MRI anesthesia type?
- MRI issues?
- commonly used meds
- MRI=usually sedation, sometimes general in pediatrics, LMA good choice
- patient must be motionless, no metal tanks, poor access to patient, hypothermia, dim lighting, loud noise (100dB), no metal PERIOD!
- Propofol, brevital, ketamine, TIVA
- cardiac cath lap anesthesia; type & meds:
- procedures done in cath lab:
- cath lab issues:
- cath lab anesthesia meds: sedation: fentanyl, versed, propofol
- procedures in cath lab:
a) cardioversion
b) AICD insertion
c) cardiac ablation
d) NIPS
e) neuro coiling
f) tips - cath lab issues: cramped quarters
Endoscopy:
procedures and medications used (and medications to avoid)
endo: mostly propofol iv bolus of 40-100 mg slow ivpush
1. panendo: avoid versed, give antisialogogue
2. colonoscopy: avoid versed
3. ERCP: best done under GA with (OET tube-secured)
Pschiatric procedures: types:
1. meds used:
2. respiratory??:
3, 4. adjunct meds and why:
ECT-induce seizure, tx schizo
- medications- propofol and succ (very, very short procedure)
- hyperventilation is key ??
- antihypertensives: labetolol (bp may go up post shock)
- anticholinergics (for succ etc)
regional anesthetics: Subarachnoid Block (SAB)
- what is it?
- what meds are commonly (and least commonly) used
SAB: local anesthetic is injected into subarachnoid space causing sensory block at spinal nerve roots. Meds: 1. lidocaine (xylocaine)(rarely used) 2. tetracaine (ponticaine) 3. bupivicaine (marcaine)
xylocaine: trade name?
pharmacodynamics:
-lidocaine
dose: 50-75 mg
onset: 5 minutes
duration: 1-1.5 hours
(used for up to 1 hour cases)
tetracaine: trade name?
pharmacodynamics:
- pontacaine
dose: 10-14 mg
onset: 5-10 min
duration: 1+hrs. 3 hrs if epinephrine added
bupivicaine: trade name?
pharmacodynamics:
- marcaine
dose: 7.5-10 mg
onset: 5 min
duration: 90 min-2.5 hours
Cardiovascular effects (pt. 1):
- a)what is the first effect? Cause? what is change in PVR?
- a)what is next effect? cause?
- a)hypotension d/t sympathetic blockade(dependent on height of block).
b) d/t vasodilation of venous (more than)arterial (arterial has more vasoconstriction than veins and therefore compensates), decreased PVR by 15-18% in NORMOvolemic (>in hypovolemic) - a)bradycardia
b) d/t blockage of cardiac accelerators located at T1-T4
Cardiovascular effects (part 2)
- what is a sympathectomy and where is this located?
- where does sympathetic block extend in regards to sensory bolck? motor?
- sympathectomy is blockage of sympathetic ganglionic trunk stimulus (HR, BP controls). any neuraxial anesthesia in T1 -L7 range will cause this-T1 caused complete sympathectomy.
- Sympathetic block is approx 2 vertebral levels above sensory block;
motor block is approx 2 vertebra levels below sensory block.
physiological effects of SAB and epidural:(what systems are affected)?
cardiovascular, respiratory, gastrointestinal, renal
Neuraxial anesthesia: cardiovascular effects (part 3)
- pre treatment for CV effects?
- bradycardic hypotension tx?
- non bradycardic/ or patient with CAD tx?
- when dont you treat (what is the % of baseline cutoff)?
- Preload with crstaloids prior to block (based on hydration status, age and cardiac hx)(1/2 liter old/cardiac; 1 liter young)
- treat bradycardic hypotension with ephedra in 5-10 mg increments (improving HR should improve BP)
- treat non bradycardic or CAD patient hypotension with direct acting Alpha (Phenylephrine 0.1-0.2 mg iv)
- if blood pressure within 20% of baseline, do not treat; monitor.
landmarks and positioning for SAB?
- easiest with patient seated and curled over tray table, side lying is second best.
- line between iliac crests represents L4-L5 (must be below conus medularis which ends at L2(start of cauda equina)).
- how does ephedra work?
2. how can tachyphylaxis occur?
- it is an indirect beta adrenergic agonist, which stimulates the release of norepi in synapse
- cause of tachyphylaxis is the fact that it is indirect and NT availability may decrease in synapses causing decreased efficacy
You need to give Phenylephrine 100-200 mcg (0.1-0.2 mg), how would you mix it and how much would you give?
- Phenylephrine is available in 20 mg/2 ml. in a TB syringe withdraw .3 cc (3 mg/ 3000 mcg)or .5 cc (5 mg/5000 mcg) and inject it into a 30 or 50 cc vial of saline (respectively). this will give a concentration of 100 mcg/ ml.
3000/30=100 mcg/ml or 5000/50=100mcg/ml
give 1-2 cc.
just for being stupid!!!
what are equivilencies of mg to mcg?
(always remember where your decimal point is)
(1. o mg =1000 mcg)
(0. 1 mg =100 mcg)-one decimal to left = 100
(0. 01 mg =1 mcg)-two decimals to left = 1
- why should you adjust your spinal dose (in mL) in obese?
2. by how much should you reduce?
- Obese have more narrow subarachnoid space (d/t pressure and fat in epidural space), this causes the mL amount of anesthetic to travel higher (fluid goes higher in skinnier cylinder)
- decrease mL amount by 20-25%
respiratory effects of SAB
- what are volumetric effects? What effect on phrenic nerve and diaphragm?
- what muscles are affected most? what is effect?
- respiratory effect on brain?
- decreased VC (vital capacity) due to a decrease in ERV (expiratory reserve volume) related to paralysos of abdominal muscles necessary for forced exhalation (NOT due to effect in phrenic nerve (C3,4,5) which controls diaphragm).
- expiratory muscles (abd and internal and innermost intercostals) affected most- therefore coughing/ clearing of secretions is diminished
- hypoperfusion/hypo-oxygenation of resp centers of brain (d/t decreased resp effort) leads to respiratory arrest
what spinal ligaments will one go through when doing a sub arachnoid block (in order)?
- supraspinous ligament
- interspinos ligament
- ligamentum flavum (will be the “pop” before entering the subarachnoid space).
For an epidural, what ligaments will one pass thru?
- suparspinous ligament
- interspinos ligament
- epidural space
- what size needle do you use for a spinal?
- what else do you use?
- what do you do when you see csf?
- what is the last step?
- needle is 27g
- introducer (that needle goes through)
- you will see csf then take stylette out
- aspirate and flush LA
how long does it take for an epidural to kick in (before knife hits skin, you must wait this long)!
10-15 minutes
what is the cause of N/V with spinal anesthesia?
- # 1 most likely cause and its treatment
- possible (#2) cause
- what is the third cause (#3) what medicine can treat the nausea and the bradycardia?
- what surgical stimulation causes, how do you prevent it?
- most likely d/t hypotension, (if patient c/o nausea, check BP, (treat with w/ ephedra 10-15 mg and open fluids)
- (possible) unopposed hyperperistalsis d/t unopposed parasympathetic activity (vagal) (since the sympathetic is knocked out with spinal-sympathomectomy)
- a high spinal can cause N/V associated with cerebral ischemia- -atropine (anticholinergic- increases HR and blocks nausea)
- tugging/ traction on bowel can cause nausea- tx is T4 (high spinal)
what if your surgery runs long and your block starts to wear off
give fentanyl into epidural
renal issues with neuraxial anesthesia:
- what does spinal do to affect micturation
- what problems might that cause
- what about fluids in the OR?
- urinary retention d/t motor blockade of sympathetic to bladder
- may delay discharge or necessitate catheterization
- be judicious with fluids if no foley, high volume can worsen retention
what is the order of blockade with spinal?
2. what is the mnemonic
- autonomic- loss of vasomotor tone leads to hypotension
- sensory-anesthesia and analgesia
- motor-paralysis
- proprioception- cannot distinguish body/ limb position
(All-Students-Must-Pass)
when giving spinal anesthesia, how often do you check BP?
q 1 min x 5 min
what factors determine height of spinal?
- dosage and volume of drug
- spec grav (baricity)
- speed of injection
- vasoconstrictors (epi)
- height of patient (taller people get more)
- position of patient (sittiing up-drug sinks)
- spinal curvature
dermatome levels:
1. C3,C4,C5=?
1.diaphragm
C5,C6,C7=?
-hands and fingers
T2=?
-clavicle
T4=?
nipple line
T5=?
-xiphoid process
T8=?
-upper abdomen
T10=?
-umbilicus
T12=?
-groin
- what entails a high spinal (as in too high)
2. what does this cause?
- T3 or higher
- causes excessive sensory and motor block (breathing difficulties/ apnea, arterial hypoxemia and hypercapnea (hypercarbia)
s/s of high spinal:
- hypotension (with accompanying N/V).
- bradycardia/ arrhythmias
- respiratory depression (may begin as whispering or hoarse voice)
- hypoxia (s/s restless, agitation, hypoventilation)
- upper extremity sensory blockade (numb or tingling fingers)
treatment for high spinal?
- bradycardia/ hypotension
- hypoventilation/ resp depression
- weak respirations
- n/v
- arrhythmias
- bradycardia with escape beats/ junctional etc.
- fix hypotension and bradycardia with ephedrine, phenylephrine or atropine
- fix hypoventilation (unstable) by sedation and intubation
- fix weak respirations by assist bag or intubate
- fix NV with atropine (if bradycardic)
- lidocaine for ventricular arrhythmias if from hypoxia/ ischemia (if from spinal, DON’T use lidocaine (dont treat spinal arrhythimas with spinal medicine!!!)
- atropine for brady arrhythmias.
why should you not use robinol for bradycardia?
not enough cardiac action, use atropine
what is a total spinal?
complete blockade of sympathetic nervous system and severe hypotension with decreased cardiac output (profound CV collapse) this causes medullary ischemia leading to apnea
what is the treatment for a total spinal
treat symptomatically:
A-B-C’s etc.
implications for spinal:
- pre spinal
- positioning
- documentation
- vital signs
- oxygen
- sedation
- pre spinal- pre hydrate 500-700ml, monitors
- positioning- position for block then return to supine once block administered
- documentation- check spinal sensory level
- vital signs-pre and q1min (x5) post block
- oxygen-always administer o2
- sedation-as necessary
epidural anesthesia:
indications-
- surgical anesthesia
- analgesia during first stage of labor
- use for prolonged post op pain
Epidural:
- pros (2)
- cons (1)
epidural
- pros
- can block a small portion of nerves anywhere along the spine (spinals can only go below L2)
- can be used repeteadly for bolus doses or on a PCA pump - cons-takes 10-15 minutes to take effect
what is the test dose for an epidural
- 3-5 cc lidocaine with epi 1:200,000
2. 1-2 ml anesthetic per segment needing to be anesthetized
