In this 176th episode I welcome Dr. Gillian Isaac back to the show to discuss another 2 ABA key words. This time we discuss Barbiturates and Bier Blocks. I also take a moment up front to share some thoughts on the horrible tragedy of George Floyd’s death at the hands of the police and the importance of acknowledging white privilege and fighting for the fact that Black Lives Matter.
Reference: Clinical Anesthesia. Publication Year: 2017. Edition: 8th Ed. Authors/Editor: Barash, Paul G.; Cullen, Bruce F.; Stoelting, Robert K.; Cahalan, Michael K.; et al.
Outline by Brian Park, MD
Awakening after a single dose of thiopental is caused by redistribution from the brain primarily to which of the following sites?
Which of the following is associated with ↑ duration of clinical narcosis following infusion of total dose 10mg /kg thiopental over 3 hrs?
(A) alcoholism in remission
(E) use of appetite suppressants
Compared with thiopental, methohexital is characterized by:
(A) better absorption after rectal administration
(B) greater protein binding
(C) greater hepatic clearance
(D) larger volume of distribution
(E) more complete biotransformation
The duration of action of an induction dose of thiopental is determined primarily by its
(A) rate of elimination
(B) rate of metabolism
(C) redistribution from brain to fat
(D) redistribution from brain to muscle
(E) hepatic extraction
Each of the following affects the induction dose of thiopental EXCEPT
(A) acute ethanol intoxication
(B) chronic use of barbiturates
(C) intravascular volume
(D) rate of hepatic extraction of thiopental
(E) serum albumin concentration
Which of the following statements about thiopental is true?
(A) Rapid uptake into maternal tissues limits its transfer to the fetus
(B) Its short duration of action is due to its extensive binding to plasma proteins
(C) Accumulation in fat leads to acute tolerance
(D) Alkalinity of solution causes respiratory depression
(E) Uptake into brain is slowed by respiratory acidosis
A healthy, but obese, 110-kg woman is scheduled for gastric stapling. Compared with that required at her ideal weight, the dose of thiopental required for anesthetic induction would likely be increased because of changes in?
(A) blood volume
(B) muscle mass
(C) circulation time
(D) body fat
(E) metabolic rate
Pain after 8ml inject of thiopental 2.5% through right radial catheter. Hand remains pink. Most appropriate next step?
(A) Inject lidocaine into catheter
(B) Inject nitroglycerin into catheter
(C) Inject papaverine into catheter
(D) R stellate ganglion block
(E) No intervention
Which of following barb-protection from cerebral ischemia is true?
(A) May be achieved w/ dose low enough to avoid cardiovascular effects
(B) Linear dose related
(C) Improve neuro outcome following card arrest
(D) Most useful for patients with focal ischemia
(E) Unrelated to EEG activity
Most likely to increase duration of seizure following ECT using barb and sux for GA?
a) admin atropine
b) change to benzodiazepine for induction
c) change to etomidate
d) add phenytoin to preop med (anti-seizure medication)
e) decrease barb used
Middle aged 70kg for elective craniotomy for brain tumor. Preop: alert, papilledema present. Induced w/ thiopental 300mg, sux 100mg → intubate → immediate bucking occurs. Best immediate mgt?
a) Admin sux 100mg iv
b) Fentanyl500mcg iv
c) Hyperventilate with isoflurane 2%
d) Admin thiopental 400mg IV
e) Hyperventilate + admin lido 1mg/kg
50M for emergent crani for evacuation of epidural hematoma. GCS 6. HR 54, BP 190/110. Most appropriate initial management?
70kg 46M undergo clipping of cerebral aneurysm w/ N2O , opioid relaxant anesthesia. as surgeon about to enter dura, it’s noted to be tense and bulging. HR 100, MAP 90. PaO2 120, PaCO2 23, pH 7.5. What should be done immediately?
a) hyperventilate to PaCO2 15-20
b) admin furosemide 20mg IV
c) adim mannitol 0.5mg/kg
d) admin thiopental 250 increments
e) add halothane to deepen
During crani for supratentorial tumor, 28M receives N2O, O2, isoflurane. Vent controlled to maintain PACO2 25. Nasopharyngeal temperature 35.8. On opening dura, surgeon notes dura bulging . Most appropriate management ?
a) ↓ iso conc.
b) hyperventilate further
c) stop N2O
e) muscle relaxant
Depression of cerebral O2 requirement below level required to create isoelectric EEG can be achieved by:
a) admin isoflurane
b) admin nimodipine
Surgery cancelled after 10 min of IVRA with 50ml 0.5% lido. To terminate anesthesia safely, what is most appropriate timing for deflating tourniquet?
a) immediate after benzo admin
b) immediate after ephedrine
c) immediately, followed by inflation/deflation
d) in no less than 20 min after initial injection
e) in no less than 45 min after initial injection
Primary determinant of duration of IVRA?
a) tourniquet duration
b) capacitance of venous system of extremities
c) local anesthetic agent injected
d) volume of solution
e) method of exsanguinating
Which of following is true about bier block?
a) useful for postop pain
b) can be used for extremity surgery 2-3hr
c) bupivacaine is an alternative choice
d) lido most commonly used
All acceptable agents to use of bier block, except
a) 0.5% lido
b) 0.5% bupi
c) 0.25% bupi
d) 0.5% prilocaine
55kg man scheduled for hand surgery with IVRA w/ 0.5% lido 15 ml. Which of following is true?
a) contraindicated in sickle cell disease
b) mottling of skin after injection didcates abandonment of technique
c) tourniquet discomfort is indication to inject more local
d) bupivacaine0.5% can be substituted to prolong anesthesia
e) epi 1:400,000 should be added to prolong
Tourniquet with dual bladder used for IVRA for UE. At what point should distal tourniquet be inflated?
a) during injection of local anesthetic
b) after patient complains of tourniquet pain
c) co-inflation with proximal tourniquet
d) after proximal tourniquet deflated
e) prior to exsanguination
Which of following s/sx of lidocaine toxicity from high levels following IVRA?
c) lightheadedness, dizziness
d) tonic-clonic seizures