Truelearn Flashcards
perioperative conditions leading to sickling:
SIX H’s cause SICKling (HbS)
- Hypothermia
- Hyperthermia
- Hypoxemia
- Hypotension
- Hypovolemia
- H+ ions (acidosis)
Lumbar plexus block, what is blocked and what spared?
Aka psoas compartment block: Blocked: - femoral - obturator - iliohypogastric - genitofemoral - lat fem cut
Spared:
- sciatic nerve
Law of laplace
T(wall tension)=(P*r)/(2h)
h= wall thickness P= pressure in ventricle.
Meld vs child Pugh
Meld:
I Crush Several Beers Daily
(INR, creatinine, sodium, bilirubin, dialysis)
Child-Pugh:
Pour Another Beer At Eleven
(PT, ascites, bilirubin, albumin, is encephalopathy)
Factors increasing MAC:
Drug
- amphetamine
- cocaine
- ephedrine
- Chronic Etoh
- highest street 6 months
Electrolyte:
- hypernatremia
Hyperthermia
Red hair
Factors decreasing MAC:
Drugs:
- alpha 2 antagonists(clonidine, precidex)
- acute Etoh
- local anesthetic
- lithium
- verapamil
- chronic amphetamine use
Electrolyte:
Hyponatremia
Elderly Anemia Hypothermia Hypoxia Pregnancy
Gabapentin receptor for action
Calcium channnel A2-delta
Chemotherapeutic toxicity’s:
- Cisplatin/carboplatin: acoustic nerve, nephrotoxicity
- vincristine: peripheral neuropathy
- bleomycin/busulfan: pulm fibrosis
- Trastuzumab: cardiotoxicity
- Doxorubicin: cardiotoxicity
- 5-FU, 6-MP, methotrexate: myelosuppression
Papillary muscle blood supply
Posterior-medial: RCA
Antero-lateral: Lcx and LAD
Major source of heat production in neonates and infants?
Nonshivering thermogenesis, triggered by:
- Norepinephrine
- glucocorticoids
- thyroxine
Inhibited by:
- volatile anesthetic
- B blockers
Drugs that typically follow zero-order kinetics are:
THE PAW: theophylline, heparin, ethanol, phenytoin, aspirin, warfarin.
Agents with low blood:gas partition coefficients
sevoflurane, desflurane
I.e. faster onset (more in the alveoli and so more in the brain)
Alpha stat pH correction for hypothermia vs pH stat
pH: temp corrected system. Aims at constant pH and adds CO2.
- Allow faster cerebral cooling and better O2 delivery.
- Concern for loss of auto-regulation and increases microemboli
Alpha: primary buffers Hco2 and phosphate decreased efficacy and so AMINO ACIDS = most important buffers.
- Maintains uncorrected CO2, pH at nml levels (more physiologic)
Alveolar Gas Equation
PAO2 = FiO2 * (Pb - PH2O) - PaCO2 / R
Amount of fibrinogen In cryo?
200mg
Amount of liquid volatile anesthetic
3 x fresh gas flow(L/min) x volume % = liquid of volatile anesthetic per hour
Anaphylactic vs anaphylactoid
Same clinical picture but anaphylactic are IgE mediated.
antinausea, antiemetic medications target what receptors?
chemoreceptor trigger zone (CTZ) of the brainstem. also known as the area postrema and, along with the nearby nucleus tractus solitarius, is felt to contain dense quantities of emetogenic chemoreceptors.
Receptors include dopamine, serotonin, acetylcholine, histamine, and NK1 types.
Aortic regurgitation
Heart rate goal?
regurgitant volume depends on the diastolic time and the pressure gradient across the aortic valve
kept above 80 bpm to prevent increases in the time for regurgitation
Aortic stenosis
valve area less than 0.8 cm2
mean pressure gradient > 40 mmHg,
AV node blood supply
PDA branch of RCA in 75% of people.
In other 25% PDA comes from circumflex
B-blocker overdose treatment
Glucagon
Blood gas interpretation: Acute and chronic changes expected.
- pH will decrease by 0.05 for every acute 10 mmHg increase in PaCO2.
- Bicarbonate increases 2.0 mEq/L per 10 mmHg acute increase in PaCO2.
- increase 4 mEq/L per chronic 10 mmHg increase in PaCO2, and pH will return toward normal if hypercarbia persists long enough (i.e. 1-2 days).
Volatile anesthetics currently in use. Physiological changes
decrease arterial blood pressure, SVR, and myocardial function comparably and in a dose-dependent manner
Halothane decreases CO
Volatile anesthetic with highest vapor pressure? Lowest?
- Desflurane (highest) in gas form at room temp. Vaporizer helps to not evaporate away.
- Sevoflurane (lowest)
Volatile anesthetic that augments neuromuscular blockade
Desflurane
Vasopressin-2 receptors
responsible for increased water reabsorption in states of hyperosmolarity or hypovolemia via increased translocation of aquaporin 2 channels in the distal convoluted tubule and collecting ducts
vasopressin-1 (V1) receptors
Causes vasoconstriction
unpaired t-test
comparison of two populations with respect to a single variable with numerical data
Triad of aortic stenosis
angina, syncope, and shortness of breath (dyspnea).
The degree of symptoms does not correlate with the degree of stenosis
treatment of choice for methemoglobinemia in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency.
Ascorbic acid
Treatment for anticholinergic overdose or prophylaxis against organophosphate poisoning
Physostigmine—only cholinesterase inhibitor that crosses the blood brain barrier
Timeframe for smoking cessation benefits.
Immediately less Carbonmonoxide.
48-72 hours: increased secretions and a more reactive airway
• 2-4 weeks: decreased secretions and less reactive airway
• 4-6 weeks: immune system and metabolism normalize
• 8-12 weeks: improved mucociliary transport and small airway function
Thromboelastography (TEG)
MA value decreased -> platelets.
K value prolonged -> cryoprecipitate.
R value prolonged -> FFP.
Teardrop configuration -> antifibrinolytics.
Thoractomy predictive cutoff for FEV1?
VO2 max?
40 if less than 40 then bad outcome likely.
VO2 max
< 10 ml/kg/min high risk
SVR calculation
SVR = [80 * (MAP - RAP)] ÷ CO]
Sucralfate
no effect on gastric volume and only a local effect on gastric pH
stellate ganglion blockade.
- diagnose and treat complex regional pain syndrome (CRPS) of the upper extremity
- transverse process of C6. Chassaignac tubercle (or carotid tubercle).
Ipsilateral temperature changes is the most reliable for block success.
Also should get Horner syndrome
Static respiratory system compliance equation:
CS = VT ÷ (PPL - PEEP).
CS: static compliance
VT: tidal volume
PPL: plateau pressure
spironolactone
Blocks the Na+/K+/Cl- channels in the distal convoluted tubule
Spinal anesthesia hypotension
- arterial dilation (decreased afterload),
- venodilation (decreased preload)
- bradycardia (parasympathetic dominance and/or the Bezold-Jarisch reflex)
SLN branches
“SIME” for sensory = internal,
motor = external
Shunts affects soluble or insoluble agents more? IR mainstem
insoluble (desflurane)
Severehypocalcemia findings
Hypotension, narrow pulse pressure, prolonged QT interval, widening of the QRS complexes, flattened T waves
sensory innervation below the vocal cords and motor innervation to all of the intrinsic and extrinsic muscles of the larynx
recurrent laryngeal nerve
Left side loops under aortic arch
Selective B1 blockers and unique metabolism
BEAM
- Bisopropolol
- Esmolol (RBC esterases)
- Atenolol (only one cleared by kidneys)
- Metoprolol
Reversal agent proper pairing.
Atropine—edrophonium
glycopyrrolate—neostigmine, pyridostigmine.
Residual neuromuscular blockade is defined as?
train-of-four (TOF) ratio < 0.9 measured at the adductor pollicis muscle
recurarization
remain paralyzed or weak, or to develop weakness later in the recovery room from neuro muscular blockade
Benzodiazepines
Effect on Cerebral blood flow and metabolic rate.
reduce cerebral blood flow and cerebral metabolic rate.
Body fluid composition percentages.
ECV contains one-third of TBW, represents 20% of total body weight and is composed of plasma volume (20-25%) and interstitial fluid volume (75-80%).
Boyle Law
constant temperature the volume and pressure of a gas are inversely proportional
BP reading change with transducer height change.
7.5 mm Hg per 10 cm height change
Buprenorphine
partial mu opioid agonist with possible (controversial) kappa activity
Calculate time in oxygen tank
Divide the new pressure by 3 then divide by flow rate.
(1500/3)/4 = 125 minutes.”
Carotid baroreceptors send afferent signals to circulatory brainstem centers via
Hering’s nerve (a branch of the glossopharyngeal).
Caudal epidural. Last structure to transverse before epidural space.
sacrococcygeal ligament
causes of low FRC
PANGOS: Pregnancy, Ascites, Neonatal, General anesthesia, Obesity, Supine position.
Cerebral blood flow per CO2 change.
CBF changes 1-2 mL/100 g/min per every 1 mmHg change in PaCO2.
Charles Law
volume and temperature of a gas will be directly proportional when the pressure of the system is held constant
(e.g. if the temperature is increased the gas will expand)
cholinergic symptoms, such as those seen with acetylcholinesterase inhibitors, organophosphate poisoning, and nerve agents.
SLUDGE-Mi
Salivation, Lacrimation, Urination, Defecation, Gastrointestinal upset, Emesis, Miosis. Saying the mnemonic as “Sludge Me”
cimetidine and famotidine
decrease gastric volume and increase gastric pH
Ranitidine only affects pH.
Conn syndrome
Excess aldosterone
Sodium retention (HTN), hypokalemia Metabolic alkalosis
Contraindications for closed circuit
Alcohol intoxication Sevofloruane Malnutrition Cirrhosis Ketoacidosis
Coronary artery vein pairings.
- anterior cardiac vein: RCA
- great cardiac vein: LAD
- middle cardiac vein: PDA
Corynebacterium diphtheriae, facultative anaerobe which causes diphtheria. Mechanism of effect
Inhibition of elongation factor 2 of transcription
CPP coronary perfusion pressure
CPP = (Aortic DBP – LVEDP)
cricothyroid muscles
external branch of the superior laryngeal nerve)
NOT vocal cords. So no horseness
Cushing’s triad
hypertension
bradycardia
respiratory changes
Cytochrome p450
Oxidizes
Dabigatran
oral direct thrombin inhibitor
Dalton Law
the total pressure of gas in the system is equal to the sum of the partial pressures of each component gas
Dantrolene toxicity and lab monitoring
Hepatotoxicity. LFTs.
Dead space
Lung that is ventilated but NOT perfused
Dynamic effective compliance vs static effective compliance
DEC = (Ppeak - PEEP)/delivered tidal volume
SEC= (Pplat - PEEP)/delivered tidal volume
Dynamic is affected by resistance, static is not.
ECG leads best for monitoring:
-2
2: atrial dysrhythmias
Echothiophate
inhibits pseudocholinesterase,
- potentiating succinylcholine.
Equation for standard error
SE = SD / square root (N)
estimated vaporizer output.
PP is partial pressure or saturated vapor pressure, ATM is atmospheric pressure.
Sevoflurane- 160mmhg; PP:21%; PP/atm:~1/4
Isoflurane-238mmhg; 32%; ~1/2
Extravasation of vasopressors
- limb elevation
- warm compresses
- irrigating with saline (Gault technique)
- injection of phentolamine
- consider stellate ganglion block (for upper limbs)
fenoldopam
selective dopamine-1 (D1) receptor agonist.
natriuretic and diuretic
No alpha 1 activity. Small amount of alpha 2.
Fick equation reveals SvO2. Nml value?
SvO2 = SaO2 - [VO2 ÷ (CO * Hgb * 1.36)]
Nml = 75%
- lower then more being extracted than delivered. Low CO?
- High then can’t use as well…sepsis etc
SvO2 = mixed venous oxygen saturation SaO2 = arterial oxygen saturation VO2 = total body oxygen consumption CO = cardiac output Hgb = hemoglobin concentration
first-line vasopressor for neurogenic diabetes insipidus following TBI.
Vasopressin
GABAA from GABAB
Baclofen for GABAB
Anesthetics for GABAA. (Propofol)
gadolinium-induced contrast nephropathy in patients undergoing MRIs.
Nephrogenic systemic fibrosis (NSF)
Risk factors for NSF include severe renal insufficiency (chronic kidney disease, Stage 4 or 5), hepatorenal syndrome, perioperative liver transplantation, or an acute inflammatory condition (e.g., sepsis).
Gay-Lussac Law
when the volume of a gas is held constant, the temperature and pressure of a gas are proportional
Glucagon
G-protein coupled receptors, stimulates adenyl cyclase production leading to increased cAMP
leads to increased glycogenolysis and gluconeogenesis while inhibiting glycogen synthesis in the liver.
The major counterregulatory hormone to insulin.
increases cardiac index, mean arterial pressure, and ventricular contractility
GLUT transporters
GLUT1: Erythrocytes- insulin independent
GLUT2: Hepatocytes- bi-directional insulin-independent glucose transporters
GLUT3: Brain neurons insulin-independent
GLUT4: most cell types (ie muscles)
Haldane effect
the relationship between the content of carbon dioxide in the blood and the concentration of oxyhemoglobin
Hemophilia A factor deficiency.
Factor VIII
higher blood:gas partition coefficient agents
isoflurane, enflurane, halothane
Solvable agents. More dissolved and longer on and offset.
Highest concentration of fluoride ions upon metabolism.
Sevoflurane
Hydrochlorothiazide
Blocks the Na/Cl co-transporter in the distal convoluted tubule
directly inhibit calcium excretion leading to hypercalcemia.
Hypermagnesemia EKG
PR interval prolongation and a widening QRS complex.
Can be seen by lithium use.
Subarachnoid hemorrhage: timeframe for rebleeding risk? Timeframe for vasospasm? Treatment?
- 24-48 hours
- 2-10 days
- triple H. Hypertension, hypervolemia, hemodilution
Iliac crest corresponds to what vertebral level?
L4.
Initial recovery from an induction dose of thiopental
redistribution to peripheral tissues
Liver produced factors.
II, VII, IX, X, as well as V, XI, and thrombin. Protein C.
Lorazepam metabolism
glucuronidation
major CVP abnormalities
Disorder CVP waveform changes
- Atrial fibrillation: Loss of a wave
- AV dissociation: Cannon a wave
- Tricuspid regurgitation: Tall c & v waves
Loss of x descent
- Tricuspid stenosis: Tall a & v waves Minimal y descent
- RV ischemia: Tall a & v waves Steep x & y descent M or W configuration
- Pericardial constriction: Tall a & v waves
Steep x & y descent M or W configuration
- Cardiac tamponade: Dominant x descent
Minimal y descent
Major mechanism of heat loss in operating room.
Radiation after redistribution.
MAP calculation:
MAP = [2*DP + SP]\3
Mapelson circuits: Ambu bag vs Jackson reese
Ambu: Unidirectional valve system. Not dependent on gas flows cause could use room air if needed.
JR: Mapleson F. Dependent on gas flows.
Mapleson A: most efficient for CO2 elimination and least amount of FGF.
Maximal inspiration pressure:
Used to determine ability to extubate
- nml = -90
More negative = better… ie -20 = unlikely to succeed extubation.
mechanism of pertussis toxin.
Ribosylation of the Gi protein inhibits the inhibitor of cyclic AMP, causing an increase in cAMP in the cell
medial tuberal hypothalamus
contains neurons that extend into the posterior pituitary and secrete vasopressin and oxytocin
Metformin
decreases hepatic gluconeogenesis and increases insulin sensitivity.
Metoclopramide
increases lower esophageal sphincter tone
enhances gastric emptying
Midazolam and diazepam metabolism
Oxidation
Morphine metabolites and effects of:
morphine-3-glucuronide (M3G) (55%)- inactive but can be neuro toxic in renal failure.
morphine-6-glucuronide (M6G) (10%)- active, respiratory depression.
Most likely volatile to cause carbon manoxide with strong base absorbants.
Desflurane.
Others don’t cause it.
Most potent volatile anesthetic
Halothane
most representative of abdominal muscle paralysis.
corrugator supercilii, eyebrow
most useful circuits for controlled ventilation:
Dead Bodies Can’t Argue (controlled): D > B > C > A
most useful circuits for spontaneous ventilation:
All Dogs Can Bite (spontaneously): A > D > C > B
Nalbuphine
mu opioid receptor antagonist and a kappa receptor agonist
Natural licorice inhibits what and what electrolyte abormality is seen?
11-beta-hydroxysteroid dehydrogenase
Hypokalemia.
Neuromuscular blocker most eliminated by kidneys.
Pancuronium
Neostigmine mechanism dose and max dose
acetylcholinesterase inhibitor.
Max dose 0.7mg/kg or prolonged weakness
newly diagnosed hyperthyroidism
Elevated thyroid hormone binding ratio is most consistent.
also confirmed by elevated T3, T4 (free and total), and a low or normal TSH.
Nitroprusside toxicity mechanism
1) Cyanide ions bind to cytochrome c oxidase and inhibit cellular aerobic respiration.
2) Formation of cyanmethemoglobin which is unable to carry oxygen.
3) Thiocyanate production which causes CNS-related effects.
Nitrous oxide receptors
- α-adrenergic receptors (analgesia and sympathomimetic effects),
- NMDA (analgesia and CNS depression)
- dopamine (analgesia via downstream induction of opioid release).
Non-depolarizing neuromuscular blockers mechanism
Post synaptic nicotinic receptor competitive antagonists.
Number needed to treat
1/ARR
Oxygen consumption in an adult
3-4 mL/kg/min
FRC = 30/kg
FRC divides by consumption times the %O2 = time of hypoxia.
oxygen content of blood equation
CaO2 = (0.003 x PaO2) + (Hgb x 1.34 x SaO2) CaO2 = arterial oxygen content (mL/dL), Hgb = hemoglobin (g/dL), SaO2 = oxygen saturation, PaO2 = arterial partial pressure of oxygen (mm Hg)
OXYGEN DELIVERY:
DO2 = CaO2 x CO x 10
paired t-test
one population with respect to two variables with numerical data
Phase 1 metabolism.
oxidation, reduction, or hydrolysis.
Phase 2 metabolism
conjugation
Physiologic dead space calculation
(PaCO2-PETCO2)/PaCO2
Physostigmine
anticholinesterase. used as a treatment for central anticholinergic syndrome.
Crosses blood brain barrier
Point at which laminar flow becomes turbulent. And equation.
Reynolds number (Re) Re=pvd/n
p=density of fluid
v=flow velocity
d=orifice diameter
n= viscosity
<2000 is laminar flow
>4000 turbulent dlow
possible causes of sub-ambient alarm include:
- Patient inhalation against an increased resistance in the circuit
- Patient inhalation against a collapsed reservoir bag
- A malfunctioning active closed scavenging system (excessive vacuum or valve dysfunction)
- A blocked inspiratory limb during exhalation
Post op outcome for thoractomy PPO
PPO = Pre (remaining segments/42)
potential allergen in local anesthetics
methylparaben
But main allergy is paba in aminoesters
Pouiseullie equation
Q=(delta)Ppier to the fourth/8nl
Only valid for laminar flow
precurarization dosage for any nondepolarizing agent prior to succinylcholine
10% of the ED95 dose
preoptic anterior hypothalamus
temperature homeostasis and thermoregulation
Prerenal AKI
(UOSM : POSM) >1.5
BUN:Cr >20:1
FeNa <1%
- FENa: [(PCr x UNa ) / (PNa x UCr)] x 100.
Propofol infusion syndrome
- Rhabdomyolysis
- metabolic ACIDOSIS
- hepatomegaly,
- hemodynamic instability,
- multi organ failure.
pulmonary vascular resistance (PVR) calculation:
PVR = [80 * (MPAP - PAOP)] ÷ CO
- MPAP = mean pulmonary arterial pressure (mm Hg)
- PAOP = pulmonary artery occlusion pressure or pulmonary capillary wedge pressure (mm Hg)
Pulse oximetry waves elevations/lower:
- red 660
- near Infared. 940
Falsely Elevated:
Methemoglobinemia, carboxyhemoglobinemka
Lower:
Blue green or black nail polish decreases reading.
Pyridostigmine
Used for prophylactic treatment.
range for differences between alfentanil and fentanyl.
Alfentanil has about 4 times faster onset.
Alfentanil lasts about 1/4 the duration.
Alfentanil is about 1/4 the potency (4x the dose of fentanyl).
Ranitidine
Increase gastric pH. No affect on volume.
Specificity vs sensitivity
Specificity TN= TN/(TN + FP) - rules in disease.
Sensitivity TP= TP/(TP + FP)- rules out
SpIn and snOut
