ITE Gen Clin Sciences Flashcards
Medically direct vs Medically supervised billing
Medically direct:
- preop exam
- induction and emergence
- monitor course
- physically present and available for immediate needs
- Doesn’t need to be the same physician
Medically supervised: lower pay
Doubling the distance from a radiation source decreases exposure to ____ of the original
1/4
Intensity = 1/(r^2)
Why does nitrous oxide accumulate in closed spaces?
It is 30x more soluble than nitrogen.
Nitrous oxide will leave the blood, entering closed space much faster than nitrogen can leave that closed space back to the blood.
What is most rapidly expanded if nitrous oxide is used,
- tension pneumothorax
- expansion of venous air emboli
- penumocephalus
- intravitreal gas bubbles
pneumothorax
- can double in 10 minutes
Why is use of nitrous oxide in pts with intestinal obstruction avoided?
risk of expansion of air in lumen and w/in bowel
- expansion of mucosa -> ischemia/infarcation
- intestinal rupture
- unable to close abdomen
What is more sensitive to detect VAE, Precordial doppler or PAC? What are its limitations?
Precordial doppler
- difficult in obese pts
_______ drugs cause extrapyramidal symptoms, especially in chronic, high doses, or simultaneous fashion. It can be treated with _______ meds.
Antidopaminergic drugs
Anticholinergic
- benztropine
- diphenhydramine
- atropine
Latex allergies results in the development of _____ antibodies against _____. People with fruit allergies often have _____.
IgE antibodies
Latex antigens
Antibodies that cross-react with latex
Carbon monoxide poisoning shifts the hgb-oxygen dissociation curve to the (right/left).
Left
- inhibits oxygen unloading from blood to tissues.
- hgb binds CO with a 200x affinity than O2
Hyperbaric oxygen therapy is reserved for pts with ___ (4)
- neuro involvement
- cardiac abnormalities
- HbCO > 25%
- Pregnancy
____ in the best indicator of liver transplant graft function
INR
- elevated = good liver func
Other nonspecific liver labs: AST: muscle injury Albumin: poor nutrition Bilirubin: GI bleeding or hemolysis GGT or Alk phos: biliary issues
Lung volume at which small airways begin to close
closing capacity
When closing capacity surpasses FRC, ____ increases and _____ decreases
shunt
oxygenation
The ____ score replaced the _____ score for prioritization of pts for liver transplant
MELD
Child-Pugh
Mneumonic for MELD scoring for liver transplant
I Crush Several Beers Daily
- INR
- Cr
- Sodium
- Bilirubin
- Dialysis
neuroleptic malignant syndrome occurs in pts taking _____.
antipsychotics
- 1st gen: haloperidol
- New atypical
Implications of decreased beta-receptor responsiveness in elderly patients
Limited compensatory response to stress
- If pt becomes hypotensive, they can no longer increase chronotropy, inotropy, and SVR
Ach release is (increased/decreased) with age in response to vagal stimulation
decreased
- decreased parasympathetic nervous system activity
Intercostobrachial nerve arises from ___ nerve root and supplies _______.
It is not blocked by any of the brachial plexus nerve blocks (supraclav, infraclav, interscalene, axillary n)
T2
Medial/posterior upper arm
_______ nerve is a branch of the musculocutaneous n, and provides innervation to the lateral half of the forearm.
Lateral antebrachial cutaneous
- C5-C6 nerve root
_______ nerve is a branch of the musculocutaneous n, and provides innervation to the medial half of the forearm.
medial antebrachial cutaneous n.
- C8-T1
_______ nerve provides innervation to the medial half of the hand
Ulnar
- C8-T1
_______ nerve provides innervation to the medial half of the hand
Median
- C5-C8
______ is the most common cause of an acute change in peak airway pressures and desaturation when a bronchial blocker is used for one-lung ventilation
Dislodgement of the bronchial blocker
When is Bronchospasm (inc peak airway P and desat) most typical?
During induction and emergence
How does a tension pneumo look in the OR?
Hypotension
Desaturation
Gradual inc in peak airway pressures
What is MH and Why are calcium channel blockers contraindicated in malignant hyperthermia when being treated by dantrolene?
MH: Ryanodine receptor defect - prolonged opening of channel - hypermetabolic state
Dantrolene has synergistic effect with CCB and decreases release of calcium from SR ->
- Arrhythmias
- Myocardial depression
- HyperK
- CV collapse
Each 20mg vial of dantrolene contains ___ g of mannitol
3g
- helps maintain u/o
Meralgia paresthetica is ____ and is d/t compression/stretch injury of the nerve as it passes around the anterior superior iliac spine through the inguinal ligament
a mononeuropathy of the lateral femoral cutaneous nerve
- pure sensory
*common in pregnancy
Brachial plexus injury can occur in open heart surgery (sternotomy) secondary to _____
sternal retractor use
Meperidine’s active metabolite is normeperidine, which is excreted by the kidneys. Accumulation of it is ______
neurotoxic and can cause seizures
*caution in pts with renal dysfunction
Morphine’s active metabolite is morphine-6-glucuronide, which is excreted by the kidneys. Accumulation of it is ___
known to cause sig respiratory depression
*caution in pts with renal dysfunction
Why does meperidine often have tachycardia as a common side effect?
molecule resembles atropine
Glycopyrrolate is an _____ drug that works mainly at ____ receptors.
Anticholinergic
- competitive antagonist of acetylcholine
- blocks parasympathetic effects of cholinergic surg
Muscarinic
What happens if you block muscarinic receptors on the heart?
Receptors loc at SA node
-> block = tachycardia
*Glycopyrrolate and atropine and Scopolamine is an anticholinergic
What happens if you block muscarinic receptors on the airway mucosa and bronchi?
Inhibits salivation and respiratory secretion
Also leads to bronchial muscle relaxation
*Glycopyrrolate and atropine is an anticholinergic
What happens if you block muscarinic receptors on the GI system?
decrease gastric motility and peristalsis -> constipation
*Glycopyrrolate and atropine is an anticholinergic
What happens if you block muscarinic receptors on the GU system?
Urinary retention
*Glycopyrrolate and atropine is an anticholinergic
What happens if you block muscarinic receptors on the Ophthalmic system?
pupillary dilation and photophobia
*Glycopyrrolate and atropine is an anticholinergic
What happens if you block muscarinic receptors on the neurologic system?
Glycopyrrolate does NOT cross BBB: no effect
Atropine and scopolamine: AMS and hallucinations
Symptoms seen with cholinergics
SLUDGE-Mi Salivation Lacrimation Urination Defecation GI upset Emesis Miosis
*Glycopyrrolate and atropine is an anticholinergic and has opposite effects
VOlume control ventilation delivers mechanical breath at a constant ____ until the set volume of air is delivered.
flow rate
FRC (increases/decreases) as you age
Increases
- however, Residual volume increases at a faster rate than ERV –>
effectively decreases oxygen reserves in presence of apnea
*note: closing capacity surpasses FRC with age
______ is responsible for increased small airway collapse in elderly population
Closing capacity
Which inhalational gas can inhibit DNA synthesis?
N2O - nitrous oxide
- inhibits tetrahydrofolate, which is req for DNA synthesis
Vomiting leads to (increase/decrease) in HCO3-
increase
- loss of HCl
- metabolic alkalosis
How does acupuncture help PONV?
stimulation of the P6 point (inner wrist)
- cochrane review
(True/False) diuretics can be used for both TACO and TRALI
False - only TACO
- circulatory overload
Higher blood:gas partition coefficients (or blood solubility) corresponds with:
(greater/lesser) degrees of volatile agent uptake, and thus, (faster/slower) onset of action.
Greater
Slower
*for example, Desflurane Blood:Gas partition coefficient is 0.42 and Isoflurane is 1.5. Des has lower solubility, and faster uptake.
Inhales agents with high Fa (alveolar concentration of an anesthetic) / FI (inspired concentration) value are associated with:
(higher/lower) blood solubility
lower
Blood:Gas partition coefficient of:
Desflurane is ____
Sevoflurane is ____
Isoflurane is ___.
- 42
- 65
- 5
- Des has lower solubility, and faster uptake.
Higher blood:gas partition coefficients (or blood solubility) is associated with (higher/lower) FA/FI?
*Fa (alveolar concentration of an anesthetic) / FI (inspired concentration)
lower
What is the most common cause of litigation during MAC?
1: Respiratory depression -> inadequate oxygenation/ventilation secondary to sedative/analgesic overdose
Why is it safer for an adult to donate a liver to a child?
Children have smaller liver
- Adults can donate L liver
- Less technical (no biliary tree or major vessels)
- Smaller liver resection
Acute processes that cause a sudden drop in ETCO2 (4)
VAE
Large PE
Low cardiac output (CV collapse)
Kinked ETT or sampling line disconnect
If pt had a massive venous air embolism in the OR what would you expect to see?
Drop in ETCO2
Increased end tidal nitrogen
The most common cause of sudden increase in physiologic dead space (impaired or absent perfusion of alveoli enhancing V:Q mismatch) is _______
sudden drop in cardiac output
Which reflex remains intact during GA?
Pupillary light response
- different from brain death
What is one anesthesia time unit for billing?
15 min
When to repeat an ECHO in a pt with mod-greater degree of valvular stenosis or regurgitation?
if no echo w/in 1 year
if significant physical exam change
Severe Aortic stenosis is defined as valve area < than ___ cm2 and a transvalvular pressure gradient > than ____ mmHg
< 0.8 cm2
50 mmHg
Goal HR for patients with aortic regurgitation?
> 80 bpm, increase diastolic time = less regurgitation time
Goal preload and afterload for patients with aortic regurgitation?
adequate preload/volume -> ensure forward flow
low SVR -> prevent regurg
2 most common reasons for discharge delay
- pain
2. PONV
Post op, if serum bilirubin is elevated and the AST/ALT are not, the differential is _____
- Preexisting abnormality of bilirubin metabolism
2. Hemoglobin breakdown from hemolysis or hematoma reabsorption
Post op, if both serum bilirubin and the AST/ALT is elevated, the differential is _____
Mild elevation:
- Intrahepatic cholestasis
- Extrahepatic biliary obstruction
Marked elevation”
- severe hypotension -> hepatic ischemia
- viral infection
- drugs
Management of:
- Intrahepatic cholestasis
- Extrahepatic biliary obstruction
- Intrahepatic cholestasis: supportive. resolves spontaneously
- Extrahepatic biliary obstruction: intervention depending if stricture or retained biliary stones
Which anesthetic gas is assoc with hepatic dysfunction?
Halothane hepatitis
Complications with brachial artery catheterization?
Thrombosis
Infection
Median n injury
The axillary sheath the ____ nerves.
Median, ulnar, radial n
*Musculocutaneous is outside the sheath
Brachial plexus root subdivisions mneumonic
Rugby Teams Drink Cold Beers
Roots (C5-T1) Trunks (Superior, middle, inferior) Divisions Cords Branches (msk, axillary, median, radial, ulnar n.)
Latex allergies have ____ mediated antibody response
IgE - Type 1
- delayed onset 30 min
Long thoracic n roots
Roots C5, C6, C7 - “wings to heaven”
TPN can result in (immediate/delayed) postop jaundice
delayed
- TPN associated cholestasis
Succinylcholine can increase intraocular pressure by ____ mmHg
10 mmHg
- in open globe injury, use roc - nondepolarizing NMB
Why shouldnt you use ketamine for ocular procedures?
nyastagmus
increase in IOP
If aspiration in the OR occurred and pt is stable, what do you do?
Suction the ET Supportive tx (abx not required - ie. bubbamoyer)
Bone cement implantation syndrome is characterized by ______ after methyl methacrylate implantation
Hypoxia
Hypotension
Cardiac dysrhythmias
Increase pulmonary vascular resistance
Brachial a. cannulation is most likely to injure which n?
Median n.
- immediately adjacent to brachial a.
Diff btwn mallampati II and III?
II: base of uvula and upper uvula, fauces
III: base of uvula only
Mediastinoscopy involves the videoscope being passed _______ and lifting the scope can cause compression and loss of a-line wave.
posterior to the Brachiocephalic artery
Treatment for extravasation of vasoconstrictor (ie: phenylephrine)
Sub Q phentolamine or hyaluronidase
Indications for hyperbaric oxygen therapy? (6)
- Gas bubble disease
- Poisoning (venom, CO, cyanide)
- Infections (necrotizing, refractory osteo, intracranial abscess, mucormycosis)
- Acute/Chronic ischemia
- ACUTE hypoxia (not chronic)
- Burn injury
_____ lab value is the best determinant of synthetic liver function
PT/INR
*PT is often elevated 1.5x normal if severe liver disease is present
*mneumonic is WEPT
Warfarin
Extrinsic
PT
The ____ supplies 20% of the blood to the liver, and the ____ supplies 80%
Hepatic artery
Portal vein
PT can be prolonged by _____
anticoagulants
Vit K deficiency
liver disease
Albumin has a half life of ___ days. Normal level is ___ g/dL
20
4g/dL
PTT measures the clotting time of the _____ and common pathway of coagulation
Intrinsic and common pathway
PT measures clotting time of the ______ and common pathways of coagulation
extrinsic (factor VII)
*mneumonic is WEPT
Warfarin
Extrinsic
PT
The ______ test is the gold std for diagnosis of malignant hyperthermia and tests for RYR1 gene mutation.
Halothane-caffeine contracture
Volume status is most accurate with measurement with ______.
_____ suggests fluid responsiveness
arterial pressure variation (PVV or SVV)
- SVV > 13% = suggests fluid responsiveness
Are status measures such as central venous pressure (CVP) and pulmonary artery occlusion pressure adequate indicators of volume status?
No
- dynamic measurements like pulse pressure variations (PVV) and stroke volume variations (SVV) are sensitive and specific indicators
Basic principle of arterial pressure variation (SVV or PPV)
stroke volume varies much more significantly with respiration in the presence of hypovolemia
If a pt meets at least 3 of the RCRI risk factors, he meets class IIb indication for ______ initiation ___ days before surgery
beta blocker
2-45 days BEFORE
*BB have cardioprotective effects, reduce HR and contractility -> lowers myocardial oxygen demand
(True/False) most HBV infections progress to chronic carrier status
False
- 90% do NOT progress to chronic HBV carrier
Primary prophylaxis against HBV following blood or bodily fluid exposure to HBV
HBV hyperimmune globuline
HBV vaccine should also be given
The efferent branch of the laryngospasm reflex is mediated by _____
recurrent laryngeal n.
- motor innervation
the ______ n is responsible for sensory innervation of the posterior 1/3 of the tongue
Glossopharyngeal n
The afferent branch of the laryngospasm reflex is mediated by _____
internal branch of the superior laryngeal n.
- sensory innervation of the trachea at and above level of vocal cords
Laryngospasm is a reflex that occurs when the _____ n. is stimulated, causing a reflex closure of the vocal cords with the motor innervation by the ______ n.
Superior laryngeal n
Recurrent laryngeal n
