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Flashcards in TIVA Deck (21)
1

what is a TIVA?

anesthesia including IV agents only (pure TIVA)
*may be combined with N2O and regional

2

what is the ideal TIVA drug?

ketamine, covers everything (dissociative, analgesic)
*ketamine and propofol combined are good since they offset the cons of each other

3

what are advantages of TIVA?

-smooth induction with minimal coughing, hiccoughing
-easier control of anesthetic depth
-rapid, predictable emergence with minimal hangover
-decreased incidence of emergence delirium (sevo/iso very insoluble, wake up FAST)
-lower incidence of PONV
-non triggering for malignant hyperthermia (Succs and volatile agents biggest triggers)
-ideal for neurosurgery
-absence of organ toxicity
-absence of atmospheric pollution
-avoids side effects of N2O
-autoregulation of cerebral blood flow maintained
-decreased bleeding in surgical field
-improved mucociliary transport

4

what are disadvantages of TIVA?

*increased post op analgesic demands and cost
-decrease in FVC after operation greater than BAL with sevo
-cost
*no effect on emergence delirium, but less analgesics required and decreased PONV

5

what are indications for TIVA?

-malignant hyperthermia susceptible (hx or family hx)
-cystic fibrosis (mucus makes induction and emergence long for volatiles)
-airway endoscopies, laryngeal and tracheal surgery (rigid airways cause to pollute room)
-remote locations, during transportation
-intracranial HTN (IV anes. agents cerebral vasoconstrictors; decrease CBF, ICP, and CMRO2 opposed to volatiles that cerebral vasodilate)
-craniotomy (rapid awakening for neuro checks)

6

compare continuous infusion technique vs. intermittent bolus for TIVA

continuous infusions
-minimize swings in levels of drugs seen with bolus
-can reduce total drug requirement by 25-30%
-fewer side effects
-shorter recovery times
-decreased drug costs
-provide stable depth of anesthesia

bolus
-injected quickly
-rapid onset of unconsciousness
-side effects of decreased BP and apnea

7

describe propofol

-rapid onset
-pain on injection (use lidocaine)
-myocardial effect (don't use with hypovolemia)
-apnea (25-30%; even higher with opioids)
-induction dose reduced with versed, opioids
-no accumulation (unlike Thiopental) and early restoration of cognitive and psychomotor function
*reduction in PONV

8

describe ketamine

*only IV anesthetic that can be used as the sole agent for TIVA
-hypnosis, analgesia, amnesia
-sympathetic stimulation (good for trauma and hypovolemia UNLESS catecholamines diminished then returns to baseline depressant)
-HTN, tachycardia, increased ICP, psychologic reactions (no CAD, pulm HTN, neuro; pre treat with versed)
-good for pulmonary disorders (asthma) and congenital heart babies
-discontinue 30 min prior to emergence (allow dissociative effect to wear off)
-increase PONV (unless with propofol)
-unpleasant hallucinations (pre treat with versed; combine with propofol)
-salivation (pre treat with glycopyrrolate)

9

describe ketamine and propofol combined

-offsets hemodynamic effects
-offsets respiratory effects to maintain spontaneous vent
-propofol offsets PONV and hallucinations

10

how should dosing be mixed with propofol and ketamine?

-mix ketamine with 2mg/ml of propofol
-induce with 1-2 mg/kg of propofol in mixture
-give an additional 0.5-1 mg/kg of ketamine after LOC
-infuse 140-200 mcg/kg/min first 10 mins
-100-140 mcg/kg/min for next 2 hours
-80-120 mcg/kg/min after 2 hours
*rate based on propofol

11

describe remifentanil

-rapid onset, potency 5x fentanyl
-allows high dose opioids w/o delayed recovery, no matter length of infusion time
-titrates easily
-increased shivering and post op pain (give analgesic before stopping)
-less time to emergence and less PONV
*good for craniotomies for rapid awakening (post op pain, give analgesic in time before stopping) and carotid endarterectomy (no post op pain; rapid awakening)

12

describe maintenance of remifentanil infusion

-turn on a 1 mcg/kg/min
*never bolus (stiff chest; metabolized too quickly)
-maintain at 0.1-0.4 mcg/kg/min
-metabolized rapidly by plasma esterases
-turn off 5-7 min before extubation
*start post op analgesia prior to discontinuing remifentanil (recovery 3-5 min SV)

13

describe dexmedetomidine

-used in sedation (not general)
-anxiolysis and analgesia (no loss of consciousness)
-prolonged recovery r/t higher doses required for anesthesia (compared to propofol) *good if planned to be post of ventilated
-reduced need for opioids
-decreased PONV

14

what is the most reliable sign of inadequate anesthesia?

movement

15

describe titration goals

-maintain 1-2 twitches of ToF to allow movement (weak but to see awareness)
-bispectral index (frontal EEG)
-anticipate increased requirement during intubation and skin incision
-anticipate decreased requirement during prep and drape

16

describe method of titration

-if no response for 10-15 min, the infusion rate may be reduced about 20%
-watch for movement, changes in hemodynamics to determine need to titrate
-if pt. responds, administer bolus, and increase rate to a point b/w first and second rate
*except for remifentanil, don't titrate opioids
-titrate down to allow SV at the end of surgery (slowly since surgeon still working)

17

what is the context sensitive half time of propofol?

-up to 3 hours: 10 min
-after 3 hours: 25 min
-after 8 hours: 40 min

18

what is the context sensitive half time of ketamine?

after 8 hours: 50 min

19

what is the CSHT of remifentanil?

4 min after any duration

20

what is the CSHT of sufentanil?

after 4 hours: 30 min

21

describe target controlled infusion systems

-programs pts. weight, height, age
-based on a pharmacokinetic model which describes the elimination and redistribution of the drug
-can titrate predicted blood concentration of the drug as simply as volatile agents for varying levels of surgical stimulation and individual pt. requirements