Lipid Metabolism & Lipid Lowering Drugs
Which of the following is FALSE:
a. lipoprotein complexes have a central core containing esters and triglycerides, and chylomicrons are the largest lipoprotein complex
b. HDL a potent anti-atherogenic lipoprotein due to its role in reverse cholesterol transport
c. The main role of the endogenous pathway of lipid metabolism is deriving lipids through emulsifying dietary fat and packaging lipids into chylomicrons
d. There are many risk factors for atherosclerosis, but high cholesterol or LDL are the most associated risk factors
C
That is the role of the exogenous pathway. The endogenous pathway derives lipids through synthesis by the liver, synthesizing VLDL, IDL and LDL
Bonus: What is the definition dyslipidemia?
Which of the following are postoperative complications of PONV? (Select all that apply)
a. Tachycardia and hypertension
b. Wound dehiscence
c. Bleeding
d. Aspiration
e. All the above
E. All the above
(HTN and tachycardia are VS changes as a result of increased pain)
These receptors are ligand gated sodium ion and potassium ion channels found throughout the central and peripheral nervous systems. When these receptors are agonized they stimulate the vagal pathway and initiate vomiting.
Serotonin aka 5-hydroxytryptamine type 3 receptors aka 5-HT3
Benzodiazepines are useful as an antiemetic as it is believed they decrease the synthesis and release of dopamine in the CTZ, but what would be a challenge of using midazolam to prevent PONV?
Using versed can be challenging because used as an antiemetic, it should be given near the end of case, but this can cause oversedation and prolong your emergence.
This risk factor for aspiration is an esophageal motility disorder characterized by degradation of nitric oxide producing inhibitory neurons?
Achalasia
•degeneration of neurons in the wall of the esophagus, especially the nitric oxide–producing inhibitory neurons that affect the relaxation of esophageal smooth muscle necessary for opening the lower esophageal sphincterà sphincter cannot relax à dysphagia, food stuck
What are the 4 major functions of apolipoproteins?
1. Structural role, help structure intimal lining of blood vessels
2. Act as ligands for lipoprotein receptors
3. Enzyme activators or inhibitors involved in the metabolism of lipoproteins
4. Guide the formation of lipoproteins
PONV is clinically important because it prolongs length of stay, delays recovery, and increases costs of care. What are 2 instrumental actions the SRNA can take to reduce PONV?
1. Preoperative assessment of PONV risk factors
2. Prophylactic treatment
Prophylaxis improves patient outcomes, satisfaction and quality of care
What is the screening tool called to assess for PONV risk?
Which of the following is not true when administering ondansetron?
a. There is a risk of ST segment depression
b. Its onset of action is 10-15 minutes
c. It interacts with cymbalta and could cause hallucinations
d. An appropriate IV dose for an adult patient would be 8mg
B. onset is 30 minutes
QT prolongation is hallmark cardiac side effect, though CV effects are rare, they also include chest pain, PVCs, and arrhythmias
Serotonin syndrome w/ SSRIS
Increased risk of irregular heart rhythm with albuterol
4 to 8mg IV over 2-5 minutes
True or false: to minimize the risk of PONV, you should consider reversing your patients neuromuscular blockade with sugammadex instead of neostigmine
False: neostigmine is associated with PONV and its use should be limited when possible
The SRNA knows that all of the following factors increase the risk of aspiration except:
a. The lower esophageal pressure decreases 7-14mmHg during general anesthesia
b. The use of opioids preoperatively
c. The use of cricoid pressure during intubation
d. Patient history of a hiatal hernia
c. cricoid pressure can decrease risk of aspiration during RSI due to esophageal compression
Opioids delay gastric emptrying through peripheral and central mu receptors
Match the drug and its possible side effect/anesthetic consideration:
Niacin It tastes bad and causes constipation
Gemfibrozil Can cause liver toxicity
Rosuvastatin Caution in patients taking Warfarin
Colesevelam Rare risk of myotoxicity
Niacin - liver dysfunction, not reccomended for use in liver diease
Fibrates (gemfibrozil) - potentiate the effects of warfarin
Statins - rare complications include myotoxicity, and rhabdo, patient who experience myotoxicity are at increased risk of MH
Bile acid resins (Colesevelam) - SE include palatability and constipation
The primary control of nausea and vomiting is located in the medulla oblongata. What are the primary afferent pathways involved in stimulating the vomiting center? (Select all that apply)
a. The chemoreceptor triggering zone
b. The vagal mucosal pathway via the GI system
c. The neuronal pathway via the vestibular system
d. Vagal parasympathetic fibers through alpha motor neurons
e. Reflex afferent pathways from the cerebral cortex
A, B, C, E
D is related to the efferent signals that create the motor response involved in vomiting
Match medication and its appropriate dose:
Droperidol 10mg IV
Metoclopramide 5mg IV
Prochlorperazine 25mg IV
Promethazine 0.625mg IV
Droperidol 0.625mg IV
Metoclopramide 10mg IV
Prochlorperazine 5-10mg IV
Promethazine 12.5-25mg IV
Match the Dopamine antagonist category and its associated characteristic:
Butyrophenones Has an FDA black box warning for prolonged QT
Phenothaizines Cannot be given to children
Benzamides Stimulate the GI tract via cholinergic mechanisms, which increases the rate of gastric emptying
Butyrophenones = Has an FDA black box warning for prolonged QT (Droperidol specefically)
Phenothaizines = Cannot be given to children
Benzamides = Stimulate the GI tract via cholinergic mechanisms, which increases the rate of gastric emptying
Oral antacids must be used with caution in patients with renal impairment. Pair the oral antacid with its possible adverse effect:
CaCO3 Can cause acid rebound
NaHCO3 Systemic absorption may cause neurologic, neuromuscular and cardiovascular impairment
MgOH Can cause acute appendicitis
NaHCO3- (sodium bicarb) can cause acid rebound, sodium overload with chronic use
MgOH (milk of magnesia) Systemic absorption of Mg may cause neurologic, neuromuscular and CV impairment in patients w/renal dysfunction.
CaCO3 (calcium carbonate) can produce metabolic alkalosis w/chronic rx. Transient increase in plasma Ca, hypophosphatemia. Acute appendicitis reported d/t impacted CaCO3 fecaliths. Symptomatic hypercalcemia for RF pt
AlOH (aluminum hydroxide): in pts w/CRF, plasma and tissue concentrations of aluminum may become excessive.
What is the main mechanism of metabolism of statins?
Most statins have a half life of 1-4 hours, which statin is the exception and what is its half life?
- Hepatic P450 enzymes
- Atorvistatin, 14 hours
Your patient is a 67 year old female with a history of diabetes, hyperthyroidism, and congestive heart failure. She is a nonsmoker and nondrinker. She is having a dental extraction performed under general anesthesia. What are her risk factors for PONV?
Your current GA plan includes induction with etomidate, maintenance with fentanyl and the use of nitrous oxide. Would you change anything about this plan?
- Female
- Diabetes
- Nonsmoker
- Nonsmoker
- Dental procedures
Induce with non-emetogenic agent such as propofol, consider a different maintenance plan such as low dose propofol and sevo, limit nitrous oxide use
Which of the following would be an appropriate use of antiemetic medications by the SRNA to prevent PONV intraoperatively?
a. Administering 30mg of IV Benadryl to a 45 year old male with no sig. PMH prior to emergence to antagonize histamine receptors
b. Administering 10mg IV of compazine to an 87 year old female undergoing unilateral masectomy after induction
c. Administering 4mg IV of decadron to 21 year old female undergoing a tonsillectomy with a history of anxiety and type 1 diabetes prior to emergence
d. Administering 25mcg/kg/min of propofol to a 34 year old male with a history of anxiety and depression undergoing a gender reassignment surgery
D - background proprol is an effective technique to prevent PONV and decrease the use of other emetogenic medications
a. Benadryl is extremely sedating and timing is important, recommended to give 12.5 mg if close to emergence
b. Phenothiazines are extremely sedating and should be avoided in the elderly, typical cut off is 65 y.o., better options
c. Decadon should be avoided in diabetics due to hyperglycemia
Which of the following is false?
a. Dexamethasone should be administered immediately prior to or during induction
b. Patients with parkinsons disease will need an increased dose of dopamine antagonists
c. Ephedrine 25mg IV can reduce PONV by maintaining blood pressure and cerebral perfusion
d. Scopolamine lasts for 72 hours
b - should be avoided in patients with parkinsons. risk for increased extrapyramidal symptoms
All of the following are true when administering Bicitra except:
a. 30ml should be administered PO 10 minutes before induction
b. Cannot be given to patients who take aluminum based antacids
c. Contraindicated in patients on a sodium restricted diet
d. Systemic absorption can lower systemic pH
D - Sodium citrate/citric acid >stomach > small intestine > blood stream > metabolized to sodium bicarbonate > quickly raises the systemic pH
You are pre-oping your patient for a radical hysterectomy. You are performing a med reconciliation and when you ask the patient about her last dose of simvastatin, the CRNA you're working with asks you "how does that medication work anyway?". How would you respond?
a. It works in the blood, so it can act on both the endogenous and exogenous pathway of making cholesterol
b. It works on the endogenous pathway, inhibiting HMG-CoA reductase, resulting in decreased cholesterol synthesis and increased LDL uptake by the liver
c. It works in the gut by blocking the absorption of dietary cholesterol
d. It works by increasing the number of LDL receptors on the liver, lowering plasma levels of LDL, and it increases plasma HDL levels
B, MOA of statins
a - this is how nicotinic acid (niacin) and fibrates (fibric acid derivatives) work
c - that is the MOA for bile acid resins and ezetimibe
d - this is estrogen
Which medication blocks all 5 categories of agonist activity in the chemoreceptor trigger zone?
a. Dexamethasone
b. Halothane
c. Ketamine
d. Emend
e. None of the above
No single drug can block serotonin, dopamine, histamine, acetylcholine, and neurokinin-1 (substance P) receptors - this is why we use multi-modal methods to control PONV
Which of the following is true regarding Scopolamine? (Select all that apply)
a. Blocks muscarinic 1 receptors and histamine 1 receptors
b. Should be used in caution in women
c. Onset is 45 minutes
d. Side effects include salivation and restlessness
e. Use should be avoided in patients with benign prostatic hypertrophy
A, E (as well as closed angle glaucoma, GI/GU obstruction, hepatic, renal, and metabolic disorders)
b. no indications related to female/male, should be used with caution in elderly patients due to sedating effects and risk for delirium
c. onset is approx 2 hours, this is why its placed preop
d. side effects include sedation, dry mouth, blurred vision, and dizziness
List the drug category each of these belong to and match the drug to its onset
Omeprazole 2.5 hours PO, 10-15 mins IV
Reglan 2-4 hours PO, 1-2 hours IV
Pantoprazole PO 1-3 hours, IV 30 mins - 1 hour
Pepcid 2.5 hours PO, 10-15 mins IV
Omeprazole (PPI) - 2-4 hours PO, 1-2 hours IV, must be given >3 hours before if being used as a pre op single dose
Reglan (dopamine antagonist) - 1-3 minutes IV,
Pantoprazole (PPI) - 2.5 hours PO, 10-15 mins IV
Pepcid (famotidine), Histamine 2 receptor antagonists, PO 1-3 hours, IV 30 mins - 1 hour
Which of the following is a correct action by the SRNA who is administering histamine 2 receptor antagonists? Select all that apply
a. Choosing to administer cimetidine instead of ranitidine for a patient because of its longer duration of action
b. Providing preoperative education to the patient that there is a possible side effect of skeletal muscle pain and headache
c. Reducing the dose administered to elderly patients
d. Using famotidine for routine aspiration prophylaxis
e. Increasing the lidocaine induction dose in patients who have received cimetidine to counteract increased clearance
B, C
A - false, cimetidine DOA 6 hours, ranitidine 10 hours
D- routine prophylaxis with this medication class is not recommended
E - cimetidine is a CYP450 inducer, can slow metabolism of lidocaine resulting in lidocaine toxicity risk