Random Stuff Flashcards
What are the potential complications of various TURP irrigation fluids?
Glycine - transient blindness, hyperammonemia
Distilled water - highest risk for intravascular hemolysis, hypervolemia, and dilutional hyponatremia
Normal saline - causes electrical current dispersion but has lowest risk of TURP syndrome
Sorbitol/Mannitol - hypoglycemia, intravascular fluid expansion, and osmotic diuresis
What about Epinephrine makes it the ideal drug for anaphylaxis?
In addition to its hemodynamic support, it’s B-2 activation results in bronchodilation and inhibits the release of histamine from mast cells
What is the difference between an anaphylactic and an anaphylactoid reaction?
Clinically indistinguishable
Anaphylactic reactions are mediated by antibodies
- Require previous exposure
- IgE antibodies form antibody-antigen complex, which bind to mast cells and cause histamine release
Anaphylactoid reactions are independent of antibody binding
- Can occur on first exposure
- Antigens directly cause histamine release
What is the major toxicity of Vancomycin?
Red Man Syndrome
- Caused by rapid infusion with subsequent histamine release, resulting in flushing and hypotension
- Recommended infusion is over 60 minutes
Local phlebitis can also occur
What drugs are used for aspiration prophylaxis?
Metoclopramide - dopamine antagonist that speeds gastric emptying and increases LES pressure (does not later gastric pH)
Cimetidine/Ranitidine/Famotidine - competitive inhibitors of H2 receptors which block the histamine induced secretion of H+ by gastric parietal cells
Sodium citrate - neutralizes gastric acid and increases pH
Ondansetron - a 5HT3 (serotonin) antagonist that blocks both central and peripheral receptors involved in the vomiting reflex
Omeprazole - proton pump inhibitor that inhibits the secretion of acid
What volume is required to result in gastric aspiration? What pH?
Classically occurs with at least 0.4 ml/kg (~25 cc) of gastric contents with pH 2.5
List the ASA NPO Guidelines
2 hours: clear liquids
4 hours: breast milk
6 hours: infant formula, full liquids, light non-fatty meals
8 hours: heavy meals
Describe some factors that predispose to aspiration
Delayed gastric emptying (diabetics, obstruction, opioid use)
Increased gastric volume (obesity and pregnancy)
Disorders of the GE sphincter (hiatal hernia, achalasia, esophageal tumors)
Describe the cardiovascular effects of hyperthyroidism and hypothyroidism
Hyperthyroidism: Decreased SVR Increased HR, contractility, and lusitropy All results in increased CO Atrial fibrillation is also very common
Hypothyroidism:
Increased SVR
Decreased HR, contractility, and lusitropy
All results in decreased CO
How can you test for susceptibility to malignant hyperthermia?
The caffeine halothane contracture test is the gold standard, but requires muscle biopsy and a specialized testing center
Molecular genetic testing using a blood sample for ryanodine-receptor mutations can be diagnostic, but a negative test does not exclude susceptibilty
What drugs can be given via the endotracheal tube?
N - naloxone A - atropine V - vasopressin E - epinephrine L - lidocaine
Describe the types of familial periodic paralysis
Familial periodic paralysis is a hereditary channelopathy that leads to painless weakness during certain conditions
Hyperkalemic FPP
- frequent episodes caused by hyperkalemia
- associated with stress, hypothermia, and low blood sugar
- treated with acetazolamide, beta-agonists, and diuretics
Hypokalemic FPP
- rare episodes caused by hypokalemia
- associated with stress, hypothermia, exercise, and carbohydrate loads
- treated with azetazolamide and spironolactone (potassium-sparing diuretic)
List the ASA classifications
1 - completely healthy
2 - mild systemic disease with no functional limitations
3 - severe systemic disease with functional limitation
4 - severe disease which is constant threat to life
5 - moribund pt not expected to survive 24 hours with or without surgery
6 - brain dead pt whose organs are being harvested
What can Methylene Blue be used for? Are there any contraindications?
Methylene blue can be used for:
- treatment of refractory hypotension
- treatment of methemoglobinemia
- treatment of Alzheimer’s disease
Contraindicated in patients taking SSRIs since it inhibitis MAO, potentially causing serotonin syndrome
What are the signs/symptoms of malignant hyperthermia? What are the known triggers? What is the treatment?
Clinical signs include increased EtCO2, tachycardia, muscle rigidity, hyperthermia, and hyperkalemia
Known triggers are volatile anesthetics and succinylcholine
- For pt’s with history of MH, vaporizers should be removed from the room, CO2 absorbent should be changed, and circuit should be flushed for several minutes with O2 > 10L/minute
Treatment involves:
- Hyperventilation with 100% O2
- Dantrolene 2.5 mg/kg IV infusion
- Bicarb to treat metabolic acidosis
- Cool the patient
- Treatment of dysrhythmias (DO NOT use Ca-channel blockers)
- Treatment of hyperkalemia
Describe the renin-angiotensin-aldosterone system
Decrease renal perfusion pressure and/or decreased delivery of sodium to the distal convoluted tubule results in the release of renin from the juxtaglomerular apparatus
Renin acts on an alpha-globulin in the plasma to form angiotensin I
Angiotensin I goes to the lungs and is converted to angiotensin II by ACE
Angiotensin II goes to the zona glomerulosa of the adrenal cortex and causes secretion of aldosterone, which increases the absorption of water and sodium
- hypertension
- hypokalemia
- metabolic alkalosis
List the side effects of common chemo drugs
Cyclosporine - renal dysfunction
Cisplatin, Carboplatin - acoustic nerve damage, nephrotoxicity
Bleomycin - pulmonary fibrosis
Vincristine - peripheral neuropathy
Cyclophosphamide - hemorrhagic cystitis
What are the negative effects of perioperative hypothermia?
Increased incidence of periop MI
Dysrhythmias
Wound infection
Increased blood loss
Which NSAID or COX-2 inhibitor has been associated with the lowest cardiovascular risk?
Naproxen
What is the exact relationship between radiation exposure and distance?
Radiation exposure is inversely proportional to the square of the distance
= 1/(radius)^2
List the classic PACU discharge criteria
Respiration
O2 Saturation
Consciousness
Circulation (BP)
Activity
What are the advantages of fast-track recovery?
Faster discharge
More comfortable patients
Cost savings
Less unplanned admissions
Where are the most accurate locations to measure core temperature?
Nasopharynx
Distal esophagus
Pulmonary artery
Tympanic membrane
What are the maximum doses of Lidocaine and Epinephrine for tumescent liposuction? When would side effects appear?
Maximum dose of lidocaine = 35 - 55 mg/kg
Maximum dose of epinephrine = 0.055 mg/kg
Signs and symptoms of local anesthetic toxicity would appear 14-16 hours after liposuction as that is when peak plasma concentrations occur
What causes Fat Embolism Syndrome? What is the classic triad? How is it treated?
FES is caused by fat globules gaining access to venous blood from the marrow of disrupted long bones - occurs in patients with closed long bone fractures or during intramedullary instrumentation
Classic triad consists of petechiae, hypoxemia, and altered mental status
Treatment is supportive therapy - prompt recognition, respiratory support, fluid resuscitation, and stabilization of long bone fractures
What are the potential complications after parathyroid/thyroid surgery?
Injury to recurrent laryngeal nerve - immediate hoarsness and stridor if bilateral due to vocal cords assuming a midline position
Hematomas - occur in the immediate post-operative period and cause respiratory distress by compressing the airway
Laryngeal edema - an early complication often seen in PACU that resolves with time
Hypocalcemia - often occurs about 24 hours post-op and is associated with muscle spasms and late-onset stridor
Injury to the superior laryngeal nerve - voice becomes slightly weak or hoarse and voice tires easily
How do you calculate sodium deficit?
Sodium deficit = (140 - serum sodium) x (body weight x 0.6)
What is the most common cause of fires in the OR?
Electrocautery
What is myotonic dystrophy? What are its triggers? How is it treated?
Myotonic dystrophy is a group of diseases resulting in persistent contracture of skeletal muscle following voluntary movement or external stimulation
Triggers include shivering due to hypothermia, neostigmine, succinylcholine, and direct surgical stimulation of muscle
Treatment is with phenytoin, quinine, and procainamide
- neuromuscular blocking drugs DO NOT treat myotonic episodes
What metabolic changes are frequently seen in patients on TPN?
Most commonly associated with hypercapnia, hyperglycemia, and hypophosphatemia
- can also cause hepatic steatosis, hypokalemia, and hypomagnesemia
- acute liver injury can also cause elevated PT
What are the benefits of smoking cessation? What is the ideal time frame?
Smoking cessation leads to:
- decreased cyanide levels, resulting in improved oxygen utilization
- decreased carbon monoxide levels, resulting in improved oxygen delivery
- decreased nicotine levels, resulting in vasodilation
Optimal time frame is at least 1 month prior to surgery
- pt’s actually produce more sputum within 1 week of smoking cessation, so may be at increased risk for pulmonary complications
Which cardiovascular drugs can be given IM?
Atropine Glycopyrrolate Ephedrine Phenylephrine Epinephrine Hydralazine
Norepinephrine CANNOT be given IM and will cause localized ischemia and tissue necrosis
What is Achondroplasia? What anesthetic concerns are there?
Achondroplasia is the most common form of dwarfism
- normal sized head, thorax, and abdomen, but shortened extremities
Often associated with:
- atlantoaxial instability
- sleep apnea
- significant lumbar lordosis
Which drugs can precipitate a flare of Acute Intermittent Porphyria?
Barbituates Benzos Nifedepine Glucocorticoids Alcohol
What are the normal values of serum and urine sodium and osmolality? How are these values affected in SIADH?
Serum Na = 135-145
Serum Osm ~ 300
Urine Na = 20
Urine Osm ~ 100
In SIADH:
- Decreased serum Na
- Decreased serum Osm
- Increased urine Na
- Increased urine Osm
What conditions are associated with Malignant Hyperthermia?
Central core disease
Multiminicore disease
King Denborough syndrome
Hyper-/Hypo-kalemic periodic paralysis
What transient changes are seen after release of an extremity tourniquet?
Metabolic acidosis
Increase in serum K+
Increased in EtCO2
Decreased systemic BP
Decreased core temperature
What variables go into the MELD score? What about the Child-Pugh score?
MELD: “I Crush Beer Daily”
- INR
- Creatinine
- Bilirubin
- Dialysis
Child-Pugh: “Pour Another Beer At Eleven”
- PT
- Ascites
- Bilirubin
- Albumin
- Encephalopathy
What is the ideal tourniquet pressure for upper and lower extremity cases?
Upper extremity tourniquet should be at least 50 mmHg above the systolic BP
Lower extremity tourniquet should be at least 100 mmHg above the systolic BP
What is the maximum dose of lidocaine that can be given during local infiltration? How about with epi?
Max dose of lidocaine alone: 4.5 mg/kg
Max dose of lidocaine with Epi (1:200,000): 7 mg/kg
During ACLS, how can correct placement of the ETT be confirmed?
Ideally, continuous waveform capnography should be used
- if unavailable, colorimetric or non-waveform CO2 detection should be used
- if no forms of CO2 detection are available, an esophageal detector device can be used
Describe how the body adapts to hypoxemia at high altitudes
Short-term (first few hours):
- increased minute ventilation and CO
Intermediate (hours to days):
- leftward shift of O2-HgB dissociation curve
- CSF bicarbonate loss
- enhanced renal bicarbonate excretion
Long-term (weeks)
- increased hemoglobin
- as hemoglobin increases, CO returns to normal
All results in normal pH, decreased PaCO2, decreased bicarbonate, increased O2 delivery
Define SIRS, Sepsis, Severe sepsis, and Septic shock
SIRS:
- Temperature over 38 or under 36
- HR > 90
- RR > 20
- WBC over 12000 or under 4000
Sepsis is SIRS with a presumed source
Severe sepsis occurs with hypotension, hypoperfusion, or organ dysfunction
Septic shock is sepsis refractory to fluid resuscitation
How does thyroid storm present? How is it treated?
Thyroid storm presents with fever, tachycardia, arrhythmia, vomiting, dehydration, and potentially coma
Treatment includes B-blockers to initially treat symptoms, followed by thyrostatic medications (carbimazole, methimazole, propylthiouracil)
- ultimately surgery or radioactive iodine may be necessary if resistant to medical management
Where are the 4 anatomical sites recommended for IO access? How does its compare to central access? What is the complication rate?
Anatomical sites recommended for IO access include the sternum, proximal tibia, distal tibia, and proximal humerus
- infusion rates: sternum > humerus > tibia
Compared to central access:
- IO first attempt success rate is much higher
- IO access is 4-5 times faster
- Lower infection rate
Major complications occur in less than 1% of insertions
Intra-operatively, how can you differentiate between light anesthesia, thyroid storm, pheochromocytoma, and malignant hyperthermia?
Light anesthesia presents with tachycardia and hypertension
Thyroid storm presents with tachycardia, hypertension, and hyperthermia
- sometimes associated with increased ETCO2
Pheochromocytoma presents with tachycardia, hyperthermia, and severe hypertension
Malignant hyperthermia presents with tachycardia, hypertension, hyperthermia, metabolic acidosis, and increased ETCO2
What is the treatment algorithm for DKA?
1) Vigorous IV hydration
2) Inuslin
- correction of hyperglycemia should not occur faster than 100 mg/dL/hour
3) potassium correction
What is the treatment of intra-op hypotension due to ACE inhibitors?
1) IV hydration
2) Phenylephrine +/- Ephedrine +/- Glyco
3) Norepinephrine
- Norepi is preferred over vaso as vaso does not improve CO and may reduce GI blood flow
