TIVA Flashcards
What is a TIVA?
Total intravenous anesthetic - an anesthetic including intravenous agents only; CAN be combined with nitrous oxide and regional.
Advantages of TIVA (8)
Smooth induction with minimal coughing/hiccups
Easier control of anesthetic depth
Rapid, predictable emergence with minimal hangover
Decreased incidence of emergence delirium (disputed)
Lower incidence of PONV
Non-triggering for MH
Improved mucociliary transport
Improved V/Q matching
For what kind of surgery is TIVA particularly advantageous?
Neurosurgery; reduced CBF and CMRO2; allows intraop neuro monitoring; also, autoregulation of CBF is better maintained as volatile agents can cause a dose-dependent decrease in autoregulation
For which organ does TIVA present an advantage over volatile?
Kidneys
What makes TIVA preferable for a rigid bronchoscopy?
Prevents atmospheric pollution in the OR with the lack of a closed system present with rigid bronch
For what kind of non-surgical procedure is TIVA used? Why?
ECT; very brief GA needed; patients can wake up quickly from propofol
Propofol is an anticonvulsant that could potentially decrease the effectiveness so ECT, however, ketamine decreases seizure threshold, so the two can be used together to balance each other’s effects
What is an advantage of TIVA noted in ENT surgery?
Decreased bleeding in surgical field
Disadvantages of TIVA (4)
Increased post-op analgesic demands and cost
Decrease in forced vital capacity after operation greater than BAL with sevo
Greater cost
No effect on emergence delirium in peds
Indications for TIVA (7)
MH-susceptible patients
CF patients
AW endoscopies, laryngeal and tracheal surgery
Remote cases and during transport
ECT
Intracranial hypertension
Emergence delirium prevention (with Precedex but not Ketamine)
What are the advantages of continuous infusion TIVA over intermittent bolus TIVA? (6)
Minimize swings in drug levels Reduce total drug requirements by 25-30% Fewer side effects Shorter recovery time/awakening Decreased drug costs Stable depth of anesthesia
How does a bolus dose induction vs a continuous dose induction compare in TIVA?
Bolus caused rapid onset of unconsciousness but decreased BP and apnea as well as requiring more drug.
Continuous infusion cause slower loss of consciousness but lower dose of drug required and side effects minimized.
____ is similar between TIVA without __-______ and volatile with __-______.
PONV; anti-emetic; anti-emetic
What is the only IV anesthetic that can be used as a sole anesthetic agent in TIVA?
Ketamine
Ketamine is particularly good for what kind of patients?
Trauma, hypovolemia
Ketamine could have an adverse effect on patients with what diagnoses?
CAD, pulmonary htn, increased ICP
What effect does ketamine have on ED in patients with PTSD?
Decrease
What are the benefits of using ketamine with propofol?
Offsetting hemodynamic and respiratory effects
Propofol offsets PONV and hallucinations
What are the advantages of remifentanil use in TIVA?
Rapid onset, highly potent
CSHT does not increase regardless of length of infusion (plasma esterases)
Easily titratable
Quick emergence, less PONV
Disadvantage of remifentanil
Hyperalgesia, shivering; requires initiation of post-op analgesia before discontinuing remi
What are indications for dexmedetomidine?
Sedation, anxiolysis/ED, analgesia; can’t induce unconsciousness alone
How does recovery of TIVA doses of dexmedetomidine compare with propofol?
Recovery is longer with dexmedetomidine at doses required for anesthesia
What is the advantage of combining Precedex with propofol?
Deep sedation with cardiovascular stability and fewer adverse effect than either drug alone; reduced need for opioids and decreased PONV
What is the most reliable sign of inadequate anesthesia?
MOVEMENT
Since movement is the best indicator for TIVA titration, what factors should the CRNA consider in monitoring the patient?
Maintain 1-2 TOF twitches to allow movement
Use BIS monitor
Define half-time
Time required for concentration in the central compartment to decrease by 50%
What does context-sensitive half-time take into consideration?
Duration of infusion
Guides d/c of infusions for emergence
Propofol maintenance infusion rate
50-150 mcg/kg/min
What equipment is indicated for TIVA?
Large syringes, low volume tubing, single stopcock, multiple stopcock, labels, infusion pump (set for drug, kg, rate, concentration, bolus), t-piece for IV
Troubleshooting during a TIVA, the CRNA may discover that the infusion is not reaching the patient because…(4)
Tubing is disconnected
Infusion pump is incorrectly programmed
Plunger is not in clamp
Stopcock is closed
In cases of what length TIVA and BAL have equal hemodynamic stability and similar recovery?
Up to 1 hour
Why do some CRNAs dislike TIVA?
Set-up takes longer
What is a TCI? By what variable do they titrate?
Target-controlled infusion systems are pumps that the CRNA may program with the patient’s, weight, height, and age, and will administer medication based on a pharmacokinetic model of elimination and redistribution.
Predicted blood concentrations of drug
Since most pharmacokinetic models are developed in ____, _______, and _________ _________ - use caution with patients with ____________, ________, _______, _________ ______ ________, and ________.
young; healthy; non-obese volunteers; co-morbidities; elderly; obese; critical care infusions; pediatric
Use BIS and titrate to clinical effect!
Ketamine may cause a paradoxical increase in…
pEEG
