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