AP 2 Test 3 Flashcards
Glomerular filtration pressure is about __% of mean arterial pressure
60
What is the major function of the proximal tubule?
Sodium reabsorption
What part of the nephron is the site of aldosterone mediated Na+ reabsorption?
Distal tubule
How does aldosterone affect Na/K ATPase in the collecting duct?
It enhances the activity which increases the number of open K+ and Na+ channels to favor reabsorption into the plasma
What part of the nephron is the principle site of antidiuretic hormone?
Medullary portion of collecting tubule
What physiologic changes causes the kidneys to release renin?
1) Sympathetic stimulation
2) Hypotension
3) Decreased sodium delivery
Renal failure symptoms aren’t detected until less than __% of functioning nephrons remain
40
What is creatinine?
A byproduct of muscle metabolism that is fairly constant and a good indicator of renal health
What are normal creatinine levels in men?
0.8-1.3
What are normal creatinine levels in women?
0.6-1
How do you calculate creatinine clearance?
[(140-age) x lean body weight] / (72 x plasma creatinine)
What is normal creatinine clearance values?
100-200
Creatinine clearance below __ indicats renal failure
25
Creatinine clearance below __ indicates end stage renal failure
10
How are creatinine levels related to glomerular filtration rate?
Inversely proportional
What physiologic state can affect BUN levels?
Hypovolemia
What is the normal range for BUN?
10-20
BUN:Creatinine ratios greater than ____ are seen in volume depletion and edematous disorders
15:1
Urine pH above 7 in the presence of systemic acidosis indicates what?
Renal tubular acidosis
Protein excretion greater than ___ is significant when screening for proteinurea
150
What causes acute glomerular nephritis?
An antibody-antigen reaction
Acute glomerular nephritis usually occurs after infection from which bacteria?
Beta streptococci
What is Polycystic Kidney Disease?
An autosomal genetic disease that causes cysts on the kidneys
What conditions are associated with Polycystic Kidney Disease?
Aortic aneurysms, brain aneurysms, HTN, chronic renal disease
How does renal artery stenosis lead to hypertension?
The afferent arterioles read a decreased blood pressure due to the stenotic renal artery and release renin which increases BP
What causes diabetic renal neuropathy?
Glucose increases past the kidneys capacity to reabsorb. This causes more water to be excreted and the sodium in the urine becomes diluted which triggers macula densa cells to secrete renin and decrease blood flow to the kidney.
What is hepatorenal syndrome?
Rapid deterioration in renal function secondary to liver failure
Which surgeries have the highest incidence of patients with acute kidney injury?
Cardiac
What is azotemia?
The rapid deterioration in renal function that results in retention of nitrogenous waste products in the blood
What causes pre-renal azotemia?
Decrease in renal perfusion due to hypotension or hypovolemia
How can you treat pre and post renal failure to avoid renal azotemia?
Preoperative volume loading
How does most perioperative AKI occur?
Renal ischemia due to hypotension or hypovolemia
How does volume loading avoid AKI?
It suppresses renin and increases ANP release
Optimizing what 3 physiologic parameters reduces AKI and mortality by over 50%?
1) MAP
2) Preload
3) Cardiac output
MAP below __ mmHg is associated with AKI
60
There is a graded increase in AKI for pre-op Hbg less than __
12
Oliguria is defined as having a urine output less than ___ cc/day
400
What are the treatments available for improving renal perfusion?
- Treat hypovolemia
- Treat/raise MAP
- Pressors
- Dopaminergic dilators such as dopamine or fenoldapam
What fluid doubles the incidence of AKI when compared to LR?
Normal saline
How do most diuretics increase urinary output?
By decreasing reabsorption of Na/K and water
How do osmotic diuretics increase urine output?
Their presence in the proximal tubule limits passive water reabsorption
What is the dose for Mannitol (osmotic diuretic)?
0.25-1g/kg
How should you administer Mannitol? Why?
Give over 20 minutes b/c if its given too quickly it can increase blood osmolarity and draw fluid into the bloodstream, causing increase in intravascular volume and possibly initiating cardiac failure in susceptible patients
How do carbonic anhydrase inhibitors increase urine output?
They interfere with Na+ reabsorption and H+ secretion in the proximal tubules
What is the dose of Diamox (CA inhibitor) to increase urine output?
250-500mg
How do loop diuretics work to increase urine output?
Inhibit Na+ and K+ reabsorption in the thick ascending loop of henle
What is the dose of Lasix?
10-100mg
What is the dose of Bumetetanide/Bumex?
0.5-1mg
What can be caused by chronic usage of loop diuretics?
Hearing loss
How do diuretics work at the distal tubule?
Inhibit sodium reabsorption by competing for the Cl- site on the Na/Cl carrier protein
What is the dose of Diuril (distal tubule diuretic)?
500mg
How do aldosterone antagonists work?
Cause the excretion of Na+ and H2O follows, and keeps K+
What aldosterone antagonist is used to prevent oliguria?
Spironolactone
How do non-competitive K+ sparing diuretics work?
Inhibit Na+ reabsorption and K+ secretion by decreasing number of open Na+ channels
What is an example of a K+ sparing diuretic used to prevent oliguria?
Triamterene
What are the metabolic manifestations of renal failure?
- High K+, Mg2+, uric acid
- Low phosphate, Ca2+, albumin
What are the hematological manifestations of renal failure?
- Anemia
- Decrease white cell and platelet function
Why is there an increased cardiac output in chronic renal failure patients?
It increases to offset decrease in O2 carrying capacity and the increase in preload
What are the results of increased angiotensin levels in chronic renal failure patients?
Arterial hypertension –> increased SVR –> left ventricular hypertrophy –> congestive heart failure
What are the pulmonary manifestations of renal failure?
- Increased minute ventilation due to metabolic acidosis
- Pulmonary edema
What are the endocrine manifestations of renal failure?
Abnormal glucose tolerance secondary to peripheral resistance to insulin
What are the GI manifestations of renal failure?
- Anorexia
- N/V
- Delayed gastric emptying
- Hepatitis
What is the mainstay of treatment for chronic renal failure?
Dialysis or transplant
What is dialysis?
The process of removing solute such as toxins, electrolytes, and water from the body
What drugs are considered nephrotoxins and should be avoided when renal function is compromised?
- Antibiotics
- Anesthetic agents (methoxyflurane and enflurane)
- NSAIDs
- Contrast media
- Immunosuppressive agents
What is myoglobinuria?
Severe muscle breakdown that causes myoglobin to be filtered by the kidneys which clogs the system
What causes myoglobinuria?
- Severe muscle wasting
- Malignant hyperthermia
- Transfusion rxn
- Anaphylactic rxn
What treatments are available for myoglobinuria?
- Keep urine flowing
- Fluids
- Diuretics (mannitol)
- Alkanalize urine with sodium bicarb
What is the concern if renal patients were just dialyzed before surgery?
Anticoagulants might still be on board
What lab values should be assessed preoperatively for patients with compromised renal function?
- Recent electrolytes especially K+
- Recent CBC
- Blood glucose level
We should not use succinylcholine in renal patients unless the pre-op K+ level is less than __
5.0
What are the EKG manifestations of hyperkalemia?
- Peaked T waves
- Very flat ST segment
- Long QRS
What are the quick treatments for hyperkalemia?
- Calcium chloride
- Sodium bicarb
- Glucose and insulin
- Hyperventilation
When managing renal patients, we should exercise judicious use of what drug classes?
- Narcotics
- Benzos
- Relaxants
How should fluids be managed for renal patients?
- Very judicious use
- Use phenylephrine for low BP instead of fluid loading
- Fluids with no potassium such as normal saline
- Glucose free fluids
Rapid respirations might not always mean pain in renal patients - what else could be causing it?
Metabolic acidosis compensation or pulmonary edema
What basic parameters should be assessed postoperatively in patients with renal failure?
- Oxygen saturation
- Electrolytes and hb/hct
- Fluid balance
- Blood sugar
On average, assume __ ml/min of irrigation fluid is absorbed during TURP and TURB procedures
20
What are the deleterious affects of dilution with irrigation during TURP/TURB procedures?
CV collapse, heart failure, hypotension, pulmonary edema, hyponatremia, cerebral edema, anemia, hyperglycemia, hyperammonemia
Clinical symptoms of deleterious effects of irrigant absorption from TURB/TURPs is classified as….
TURP syndrome
What are the early signs of TURP syndrome in awake patients?
Restlessness, headache, N/V, confusion/slurred speech, tachypnea
What are the later signs of TURP syndrome?
Seizure, tachycardia and HTN followed by bradycardia and hypotension followed by CV collapse
What lab value confirms TURP syndrome?
STAT serum Na+ less than 120
What are the treatments available for TURP syndrome?
- Loop diuretics
- Restrict fluids
- Hypertonic saline for the low Na+
- Benzos for seizures
What are other issues (aside from TURP syndrome) associated with TURP/TURB procedures?
- Hypothermia
- Bladder perforation
- Coagulopathy
- Septicemia
What is a good choice of anesthesia for TURP/TURB procedures?
Spinal/epidural for good pain relief and allows you to monitor mentation
What can ECG changes can be seen during lithotripsy procedures due to shock waves?
Dysrhythmias on R waves
What type of anesthesia is usually necessary for percutaneous nephrolithotomy tube placement?
General
What are the anesthetic considerations for prostatectomies and cystectomies?
- Significant blood loss
- A line
- Good IV access
- May need indigo carmen or methylene blue
What is the more popular anesthetic method for prostatectomies/cystectomies?
General anesthesia
What are anesthetic considerations for nephrectomies?
- Potential for extensive blood loss
- Reflex renal vasoconstriction can occur at non-effected kidney and can cause post op renal failure, consider mannitol
What drugs should be considered prior to clamping the iliac vessels during renal transplants?
- Heparin
- Calcium channel blocker into graft to prevent reperfusion injury
- Mannitol
How does the autonomic nervous system correct hypertensive states?
- Decrease HR
- Vasodilation
- Increase vagal tone
- Decrease sympathetic tone
How does the autonomic nervous system correct hypotensive states?
- Increase HR
- Vasoconstriction
- Increase contractility
- Decrease vagal tone
- Increase sympathetic tone
What activates the RAA system?
Hypotension and decreased sympathetic tone
What is the ultimate result of RAA system activation?
- Increased vasopressin levels
- Increased angiotensin II
What occurs during the initiation of the RAA system?
Macula densa cells sense low fluid or low sodium concentration and prompt the juxtaglomerular cells to secrete renin into the blood
What happens after renin from the kidney and angiotensinogen from the liver is released into the blood?
Renin converts angiotensinogen to angiotensin I
What happens once angiotensinogen is converted to angiotensin I?
ACE from the pulmonary blood converts angiotensin I to angiotensin II
What happens once angiotensin I is converted to angiotensin II?
Angiotensin II stimulates vasoconstriction and aldosterone secretion from the adrenal cortex
How does aldosterone affect blood volume?
Aldosterone stimulates Na+ uptake and water reabsorption, thus increasing blood volume and arterial blood pressure
What are common causes of secondary hypertension?
- Renal disease
- Endocrine disorders
- Renal artery stenosis
- Medications
- Neurologic disorders
What is the neurologic manifestation of unmanaged hypertension?
Ischemic stroke
What are the cardiovascular manifestations of unmanaged hypertension?
Aneurysms, LVH, angina, heart failure, arrhythmias
What are the renal manifestations of unmanaged hypertension?
- Sodium retention
- Hyperuricemia
- Diminished GFR
What is a hypertensive emergency?
Severe HTN with evidence of acute end organ damage i.e. stroke, encephalopathy, LV failure, MI, renal failure
What is hypertensive urgency?
High blood pressure without signs of acute end organ damage
What is the likely etiology of a hypertensive emergency?
A very acute increase in SVR leading to acute increase in BP
Blood pressure should be lowered by about __% in the first few hours following an acute hypertensive emergency
20
What factors do the JNC-8 guidelines for hypertension depend on?
The patient’s age and co-morbid conditions
Hypertensive patients with chronic kidney disease can be managed with what drug classes?
- ACE inhibitors
- ARBs
African American hypertensive patients without chronic kidney disease can be treated with what drug classes?
- Thiazide diuretics
- Calcium channel blockers
Non-african american hypertensive patients without chronic kidney disease can be treated with what drug classes?
- Thiazide diuretics
- Calcium channel blockers
- Ace inhibitors
- ARBs
What lifestyle modifications can be made to treat hypertension?
- Weight loss
- Reduce salt intake
- Alcohol/tobacco cessation
How do thiazide diuretics (hydrochlorothiazide) work to treat HTN?
Reduces sodium reabsorption in DCT which causes water loss and decreased BP
How do loop diuretics such as Furosemide and Torsemide work to treat HTN?
- Inhibits sodium and chloride reabsorption in loop of henle to cause water loss
- Increase prostaglandin levels
How do ACE inhibitors such as Lisinopril work to treat HTN?
Blocks the conversion of angiotensin I to angiotensin II to cause vasodilation, smooth muscle relaxation, natriuresis, and decreased vasopressin release
How do angiotensin receptor blockers such as Losartan and Valsaratan work to treat HTN?
Blocks the activation of the angiotensin II receptor which causes vasodilation, smooth muscle relaxation, natriuresis, and decreased vasopressin release
How do calcium channel blockers such as Amlodipine and Nicardipine work to treat BP?
Block calcium channels thus decreasing Ca2+ levels and causing vasodilation, negative inotropy, negative chronotropy, and reduced aldosterone production
You should avoid using calcium channel blockers in patients with what co-morbid condition?
Heart failure
When are calcium channel blockers commonly used to treat HTN?
For otherwise fairly normal functioning patients who don’t respond to diuretics or ACE inhibitors
Where are B1 receptors primarily located?
Heart and kidneys
Where are B2 receptors primarily located?
Muscle
Where are B3 receptors primarily located?
Adipose tissues
How do beta blockers such as metoprolol and carvedilol work to treat HTN?
Negative chronotropy, negative inotropy, anti-arrhythmic effect, reduced aldosterone, smooth muscle relaxation
What is a true aneurysm?
Aneurysm encompassing all 3 layers of the aorta
What is a pseudo-aneurysm?
Aneurysm of just the bottom layer of the aorta
What are common etiologies of aortic aneurysms?
HTN, artherosclerosis, collagen vascular disease, bicuspid aortic valve, syphilis, hyperlipidemia, mycotic, inflammatory
What is an aortic dissection?
An intimal tear creating a false lumen for blood to enter
What is a Type A aortic dissection?
Dissection involving either the ascending aorta or both ascending and descending
What is a Type B aortic dissection?
Dissection involving just descending aorta
What are common etiologies of aortic dissections?
HTN, collagen vascular disease, biscuspid valve, inflammatory, trauma, heart surgery complication
What is carotid artery stenosis?
Narrowing of the carotid arteries primarily due to atherosclerotic disease
Which carotids are primarily affected by carotid artery stenosis?
Internals
Carotid artery stenosis greater than __% indicates intervention
70
What are common risk factors for carotid artery stenosis?
HTN, hyperlipidemia, DM, PAD, tobacco
What is Raynaud’s phenomenon? In what gender is it most common?
Vasoconstriction in extremities during periods of cold or stress. Most common in females.
What is a venous thromboembolism?
A deep vein thrombosis plus pulmonary embolism that primarily occurs in lower extremities
Total hepatic blood flow accounts for __% of cardiac output
25
Hepatic blood flow has ___ (high/low) flow, ____ (high/low) resistance
High flow, low resistance
Most patients with liver disease have ___ SVR (hi/lo), ____ cardiac output (hi/lo), and ___ arterial pressure (hi/lo).
low SVR, high cardiac output, low arterial pressure
Splanchnic volume has a major role in the body’s response to what perioperative condition?
Hypovolemia
What nerves have neural control of liver blood flow?
Vagus and splanchic
Sympathetic stimulation _______ (increase/decreases) blood flow
Decreases
How does epinephrine affect liver blood flow?
Initial vasoconstriction via alpha receptors, then dilation via beta receptors
How does glucagon affect liver blood flow?
Long lasting arterial vasodilation
How does angiotensin II affect liver blood flow?
Profound vasoconstriction
How does vasopressin affect liver blood flow?
Marked splanchnic vasoconstriction
What components of anesthesia will decrease total hepatic blood flow?
- All anesthetics that decrease cardiac output
- Controlled ventilation
- Regional anesthesia
- Controlled hypotension with sodium nitroprusside
What type of surgery decreases hepatic blood flow up to 60%?
Upper abdominal surgeries
What key protein that maintains intravascular oncotic pressure is produced by the liver?
Albumin
What is the normal range of albumin levels?
3.5-6
All coagulation factors except which 3 are produced by the liver?
3, 4, and 8
A deficiency in which coagulation factors is a good indication of hepatic dysfunction?
Vitamin K dependent factors
Which clotting test is a good indicator of acute hepatic dysfunction?
PT
Removal of what toxic metabolite is impaired in both acute and chronic liver disease?
Ammonia
How are glucose levels affect in patients with impaired liver function?
Blood glucose can rise several fold
The majority of cholesterol synthesized by the liver is converted to what?
Bile salts
What is jaundice?
The yellow-green tint of body tissue due to bilirubin accumulation in extracellular fluids
Skin discoloration is usually visible when plasma bilirubin reaches __ times normal values
3
Why does bilirubin accumulation occur
- Increased breakdown of hemoglobin (indirect bilirubin)
- Obstruction of bile duct (direct bilirubin)
Which form of bilirubin (conjugated or unconjugated) travels to the liver bound to albumin?
Unconjugated
What is the normal daily production of bilirubin?
300mg
How do narcotics affect common bile duct pressure?
Increase common bile duct pressure
Which narcotic increases common bile duct pressure the most? The least?
Fentanyl - the most
Morphine - middle
Demerol - the least
What drugs can attenuate the increase in common bile duct pressure caused by narcotics?
NTG, naloxone, atropin, glucagon
What occurs during phase I of drug biotransformation in the liver?
Oxidation w/ cytochrome P-450
What occurs during phase II of drug biotransformation in the liver?
Conjugation to water soluble for excretion
What factors affect drug metabolism in the liver?
- Blood flow, protein binding, intrinsic hepatic clearance
- Enzyme inducing compounds
- Self-induced drugs like ketamine and diazepam
What lab value is increased when bile ducts are blocked?
Alkaline phosphatase (ALP)
What lab test is the best for detecting hepatitis?
Alanine transaminase (ALT)
What lab test is a more sensitive marker for cholestatic damage?
Gamma-glutamyl transpeptidase (GGTP)
What enzyme level used to evaluate liver function is found in the liver, heart, and muscle?
Aspartate transaminase (AST)
What is the normal range for ALT levels?
5-40
What is the normal range for ALP levels?
13-39
What other tests are useful in assessing liver function?
- PT
- Total proteins
- Albumin
- Bilirubin
- Platelets
- Ammonia
How are serum albumin levels changed in patients with chronic liver disease such as cirrhosis?
Decreased
What is bilirubin?
The breakdown product of heme that is cleared from the blood by the liver
If direct bilirubin levels are normal, what are the etiologies of impaired liver function?
- Hemolysis
- Hepatitis
- Cirrhosis
If direct bilirubin levels are elevated, what is the issue? What should be suspected?
The liver is unable to secrete the bilirubin.
- Gallstones
- Cancer
What is the normal range for total bilirubin?
0.2-1.5
What is the normal range for direct/conjugated bilirubin?
0-0.3
What is the normal range for indirect/unconjugated bilirubin?
0.2-0.8
How is Hep A transmitted?
Fecal/oral route. Contaminated shell fish common
How does Hep A manifest?
Fever, jaundice, painfully enlarged liver
How is Hep B transmitted?
Blood transfusion, needle stick, sexual contact, across the placenta
How is Hep C transmitted?
Blood transfusion, needle stick, sexual contact, across the placenta
What is Hep D?
A co-infection acquired with hep B
How is Hep E transmitted?
Fecal/oral route due to contaminated water or poor hygiene
What are the top causes of acute liver failure?
- Viral hepatitis
- Drugs (acetaminophen, amiodarone, volatile anesthetics)
- Toxins
- Vascular events (ischemia)
Which hepatitis is an occupational risk for anesthesia care providers?
Hep B
What should be assessed during preop of a patient with hepatitis?
- Assess coagulation and treat with fresh frozen plasma if needed
- Glucose levels
What respiratory state should be avoided in patients with hepatitis?
Hypercarbia
Which drug classes have a prolonged affect in patients with hepatic dysfunction?
- Benzodiazepines
- Opioids
- Non-depolarizing muscle relaxants
Which opioids have prolonged effects in patients with hepatic dysfunction?
Morphine and alfentanil
Which muscle relaxants are a better choice for patients with hepatic dysfunction?
Cis and atracurium
What is cirrhosis?
Chronic disease of the liver characterized by distortion of the normal hepatic structure or scaring caused by cellular destruction
In what patients is cirrhosis most commonly seen?
- Patients with chronic viral hepatitis
- Alcholics
What is cholelithiasis?
Formation of stones in the gallbladder caused by cholesterol crystal precipitation
What is cholecystitis?
Inflammation of the gallbladder caused by a gallstone in the cystic duct
What may be considered for induction with patients presenting for cholecystectomy?
RSI b/c they may present with a recent history of N/V
The use of which drug class may prevent flow of contrast dye during a cholangiogram?
Opioids
An elevation in unconjugated bilirubin can lead to what condition?
Kernicterus, characterized by seizures and brain damage
1 unit of PRBCs contains approximately how much bilirubin?
250mg
What IV access/monitoring should be considered for a hepatic resection?
- Large bore IV
- A line
- CVC
How should post op pain be managed for a hepatic resection?
Epidural
How should you manage the patients fluid status during the hepatic resection phase?
Keep them relatively hypovolemic to minimize EBL
How many units of T&C blood should be available during a hepatic resection?
6
What is the normal range for portal vein pressures?
6-12cmH2O
What is portal hypertension?
Sustained elevation of portal vein pressure causing an increased resistance to blood flow in the liver
What are collateral channels (varices)?
Channels caused by the overload of the portal circuit in an attempt to flow around the hepatic obstruction
What causes prehepatic portal htn?
Thrombosis
What causes intrahepatic portal htn?
Cirrhosis
What causes posthepatic portal htn?
Budd-chiari syndrome, right heart failure, pericarditis
What is the clinical manifestation of severe portal hypertension?
Bleeding of varicies, particularly from the esophagus
What is ascites?
Accumulation of serous fluid in the peritoneal cavity
Ascites can be a manifestation of what other conditions?
- Cirrhosis
- Portal htn
- Increased lymph, Na+ retention
- Impaired h2o excretion
- Hypoalbuminemia
- Decreased colloid osmotic pressure
Patients with ascites often present with what condition?
Arterial hypoxemia
What are the common PaO2 values in patients with ascites?
60-70mmHg
What is the most likely cause of the arterial hypoxemia seen in patients with ascites?
Right to left intrapulmonary shunting as a result of pulmonary htn, cigarettes, or COPD
What is the common medical management of ascites?
Aldosterone antagonists such as Spironolactone
How should fluids be managed during ascites fluid removal?
Administer IV fluids, usually colloids, to prevent hypotension. No more than 1 L drained per day.
What is the mainstay treatment of coagulopathy in patients with advanced hepatic failure?
FFP
What is the greatest fear of massive blood loss in the coagulopathic liver patients?
Fibrinolysis
How does hepatic encephalopathy (hepatic coma) manifest?
- Mental confusion
- Asterixis (flapping motion of hands)
- Fetor hepaticus (fruity breath)
What are the anesthetic questions we should ask when presented with patients with advanced liver diseases?
1 - Stage of disease? 2 - Coagulopathy? 3 - Ascites? 4 - Renal compromise? 5 - Anesthetic drug issues with hepatic dysfunction? 6 - Anticipated blood loss?
The posterior pituitary secretes
A. TSH
B. Prolactin
C. Vasopressin
D. Growth hormone
C. Vasopressin
Which lobe of the pituitary gland produces hormones? Which hormones does it produce?
Anterior - ACTH, TSH, GH, FSH, LH
Which hormones are secreted by the posterior pituitary?
ADH and oxytocin
What are the principle hormones secreted by the thyroid?
Thyroxine (T4)
Triiodothyronine (T3)
Which hormone secreted by the thyroid is more potent and less protein bound?
T3
Graves Disease is an autoimmune disease causing
A) Hypothyroidism
B) Hyperthyroidism
B. Hyperthyroidism
What is the pathophysiology of hyperthyroidism?
Hyperfunction of the thyroid gland with excessive secretion of T3 or T4
What are common causes of hyperthyroidism?
- Graves disease
- TSH secreting tumors
- Iatrogenic
- Thyroiditis
What are the symptoms of hyperthyroidism?
- Weight loss
- Fatigue
- Arrhythmias (a fib, SVTs, widened pulse P)
- Anxiety
- Exopthalmos
What are the common treatments for hyperthyroidism?
- Antithyroids
- Beta blockers
- Thyroidecetomy
What can be administered to patients with hyperthyroidism pre-op to decrease hormone release?
Steroids
What beta blocker is good intra-op for patients with hyperthyroidism?
Esmolol
What intra-op drugs should be avoided in patients with hyperthyroidism?
Drugs that cause SNS stimulation
- Ketamine
- Pancuronium
- Meperidine
- Atropine
What exaggerated response can occur during induction of patients with hyperthyroidism?
Exaggerated hypotensive response
What are the major post op concerns in patients with hyperthyroidism?
- Unilateral RLN injury (manifests as hoarseness)
- Bilateral RLN injury (stridor)
- Hypocalcemia 1-3 days after surgery (parathyroid removal)
How does hyperthyroidism change MAC requirements?
No change
What is a thyrotoxic crisis (thyroid storm)?
A life threatening exacerbation of hyperthyroidism that can be caused by trauma, infection, surgery, or illness
When do thyroid storms most often appear?
6-18 hours after operation
What are the symptoms of thyroid storm?
Abrupt anxiety, fever, tachycardia, CV instability
What is the treatment of a thyroid storm?
- Cooled crystalloids
- Esmolol infusion (50-300mcg/kg/min)
- Dexamethasone (2mg every 6 hours)
- Cortisol (100-200mg)
What other condition does a thyroid storm mimic?
Malignant hyperthermia
How can you decipher a thyroid storm from MH?
A thyroid storm doesn’t cause muscle rigidity, elevated creatinine kinase, or acidosis
What drug can be given PO to inhibit conversion of T4 to T3 during a thyroid storm?
Propylthiouracil
What is the pathophysiology of primary hypothyroidism?
Dysfunction or destruction of thyroid tissue
What is the most common kind of hypothyroidism?
Hashimoto’s thyroiditis
Patients with primary hypothyroidism have __ (hi/lo) TSH levels but ___ (hi/lo) T3 and T4 levels
High TSH, low T3/T4
What causes secondary hypothyroidism?
HPA axis dysfunction iatrogenically (thyroidectomy, antithyroid meds, radioactive iodine) or due to myxedema coma
What is myxedema coma? In which patients is it most common?
Loss of deep tendon reflexes with severe hypothermia, hypoventilation, hyponatremia, hypoxia, hypotension, delirium. Most common in elderly women with long history of hypothyroidism.
What are the symptoms of hypothyroidism?
- Lethargy
- Weight gain
- Cold intolerance
- Hypoactive reflexes
What is the treatment for hypothyroidism?
PO T4 (L-thyroxine aka Synthroid)
What are intra-op considerations for patients with hypothyroidism?
- Can have severe hypotension and increased sensitivity to agents
- Diminished cardiac output
- Blunted baroreceptor reflexes
- Impaired pulmonary function
What anesthetic approach is best in patients with hypothyroidism?
Regional
If you must do a general anesthetic in patients with hypothyroidism, what induction med should be used?
Ketamine
What are post-op concerns for patients with hypothyroidism?
- Resedation
- Hypothermia
- Hypoventilation
Parathyroid hormone increases the levels of serum:
A. albumin
B. calcium
C. potassum
D. sodium
B. calcium
What serum electrolyte is decreased by parathyroid hormone?
Phosphate
What percentage of calcium in the blood is protein bound?
40%
How many parathyroid glands are there?
4
What are the common causes of primary hyperparathyroidism?
- Adenoma
- Carcinoma
- Hyperplasia
What are the common causes of secondary hyperparathyroidism?
Compensatory increase in PTH secretion due to hypocalcemia caused by renal disease or GI malabsorption
What are the symptoms of hyperparathyroidism?
- Renal stones
- HTN
- Constipation
- Fatigue
What are the medical treatments for hyperparathyroidism?
- Saline
- Loop diuretics
What are the periop anesthetic considerations for patients with hyperparathyroidism?
- Adequate hydration
- Maintenance of urine output
- Possible hypotension during induction
- Altered response to muscle relaxants
What are the EKG manifestations of hypercalcemia due to hyperparathyroidism?
- Prolonged PR interval
- Short QT interval
What is hypoparathyroidism?
Decreased PTH or resistance to PTH that causes decreased calcium - almost always iatrogenic
What is pseudohypoparathyroidism?
A congenital condition where the patient has normal PTH but kidneys don’t response
What are the symptoms of acute hypoparathyroidism after surgery?
- Paresthesias
- Neuromuscular irritability
- Restlessness
What are the symptoms of chronic hypoparathyroidism?
EKG changes, lethargy, cataracts
What is a positive Chvostek sign when screening for hypoparathyroidism?
Facial muscle twitching with manual tapping at angle of mandible
What is a positive Trousseau sign when screening for hypoparathyroidism?
Carpopedal spasm after 3 minutes of tourniquet ischemia
What is the treatment for hypoparathyroidism?
- Calcium infusion
- PO calcium
- Vitamin D
How should respiration be managed perioperatively in patients with hypoparathyroidism?
Don’t hyperventilate so you can avoid alkalosis
The Thymus is a specialized gland of the _________ system:
A) cardiovascular
B) Neurological
C) renal
D) Immune
D. immune
What does the thymus do?
Differentiates developing lymphocytes into mature T cells of the adaptive immune system
What is the pathophysiology of DiGeorge Syndrome (congenital thymic hypoplasia)?
Hypoplasia or aplasia of the parathyroid and thymus
What are the symptoms caused by DiGeorge Syndrome?
- Hypocalcemia
- Increased infections
- Congenital cardiac defects
What symptom of DiGeorge Syndrome indicates a difficult DL?
Micrognathia
What are periop considerations for patients with DiGeorge Syndrome?
- Avoid hyperventilation bc it could exacerbate hypocalcemia
- Unpredictable NMB
Cushing’s Disease is an excess of which hormone?
A) ACTH
B) Cortisol
C) Aldosterone
D) GH
B. Cortisol
What is released from the adrenal cortex?
- Glucocorticoids (cortisol)
- Anti insulin
- Minerocorticoids (aldosterone)
- Androgens
What is the net effect of aldosterone?
Increased extracellular fluid volume caused by fluid retention, decreased plasma potassium, metabolic alkalosis
What imbalance can occur with high circulating levels of anti-insulin?
Hyperglycemia
What endocrine disorder is assessed with the Chvostek and Trousseau tests?
Hypoparathyroidism
What is the only important disease process associated with the adrenal medulla?
Pheochromocytoma
What neurotransmitters are released from the adrenal medulla?
Catecholamines (NE, E, DA)
What is Cushing’s Syndrome?
ACTH stimulates excessive cortisol secretions from the adrenal cortex
What are the symptoms of Cushing’s syndrome?
Obesity, HTN, glucose intolerance, osteoporosis, muscle weakness
What are the treatments for Cushing’s syndrome?
- Radiotherapy
- Transsphenoidal resection if microadenoma is the cause
What are the preop considerations of a patient with Cushing’s syndrome?
- Consider BP
- Check for electrolyte imbalances
- Check blood sugar
- May be hypervolemia
- May be hypokalemic
- Muscle weakness may indicate sensitivity to NMB
What are the intraop considerations for a patient with Cushing’s syndrome?
- Careful positioning due to osteoporosis
- Obesity
What are the physiologic effects of excess cortisol that must be considered while managing a patient with Cushing’s syndrome?
- Systemic HTN
- Muscle weakness
- Osteoporosis
- Obesity
- Poor wound healing
- Susceptible to infections
What post op considerations are important for a patient with Cushing’s syndrome?
- Poor wound healing
- Infection prone
If Conn Syndrome involves oversecretion of Aldosterone, you would expect a patient with it to have:
A) Hypokalemic Metabolic Acidosis
B) Hyperkalemic Metabolic Alkalosis
C) Hypokalemic Metabolic Alkalosis
D) Hyperkalemic Metabolic Acidosis
C) Hypokalemic Metabolic Alkalosis
What is the cause of primary hyperaldosteronism (Conn syndrome)?
Excess secretion of aldosterone usually from a tumor, hyperplasia, or adrenal carcinoma
What are the symptoms of Conn syndrome?
Often asymptomatic but may see
- headache
- muscle cramps
- metabolic alkalosis
- hypokalemia
What are the treatments for Conn syndrome?
- Supplemental potassium
- Competitive aldosterone antagonist (Spironolactone)
What are periop considerations of a patient with Conn syndrome?
- Correction of hypokalemia
- Treatment of systemic HTN
- Don’t hyperventilate
What is the cause of primary adrenocorticoid deficiency (Addison’s disease)?
An autoimmune disease that causes
- Decreased release of glucocorticoids and mineralocorticoids
- Absence of cortisol and aldosterone
What causes secondary adrenocorticoid deficiency?
Can be caused from iatrogenic use of synthetic steriods. Causes…
- decreased ACTH from pituitary
- No cortisol
- Normal aldosterone
What symptoms of adrenocorticoid deficiency are caused by the absence of cortisol?
- Weakness
- Fatigue
- Hypoglycemia
- Hypotension
- Weight loss
What symptoms of adrenocorticoid deficiency are caused by the absence of aldosterone?
- Hyponatremia
- Hypovolemia
- Hyperkalemia
- Metabolic acidosis
- Hyperpigmentation of skin
What is Addisonian crisis? How is it triggered
Severe hypotension leading to a coma that can be triggered in steroid-dependent patients who do not receive increased doses during periods of stress
What are the treatments for adrenocorticoid defiency?
Replace steroids with hydrocortisone
What are the periop considerations for patients with adrenocorticoid deficiency?
- Be aware of addisonian crisis
- Beware of steroid withdrawal and redose steriods
- Infection prone
- Assess if pressors and fluids are working to treat hypotension
What induction drug should be avoided in patients with adrenocorticoid deficiency?
Etomidate
What are the causes of hypoaldosteronism?
- Congenital deficiency of aldosterone synthase
- Hyporeninemia
- unilateral adrenalectomy
When is hypoaldosteronism suspected?
-When the patient has hyperkalemia but no renal insufficiency
What metabolic condition could be due to hypoaldosteronism?
Hyperchloremic metabolic acidosis
What is the treatment for hypoaldosteronism?
Fludrocortisone
What are the periop considerations for patients with hypoaldosteronism?
- Patients may have heart block due to hyperkalemia and orthostatic hypotension
- Consider volume status
What is the pathophysiology of pheochromocytoma?
Tumor of the adrenal medulla causes an oversecretion of epi, norepi, and dopamine
What are the symptoms of pheochromocytoma?
Sudden onset of malignant hypertension, tachycardia, arrhythmias, headache, perspiration
Acromegaly is associated with an oversecretion of which hormone? A) ACTH B) TSH C) GH D) ADH
C) Growth Hormone
What is the most common cause of acromegaly?
Adenoma in the pituitary gland
What symptoms of acromegaly can make airway management difficult?
- Enlarged tongue and epiglottis
- Elongated mandible
- Narrowed glottic opening
What sized OETT may be best for an acromegalic patient?
A smaller OETT because of the increased incidence of subglottic stenosis
What test should be performed before placing an a-line on an acromegalic patient?
Allen’s test
What is the pathophysiology of diabetes insipidus?
Deficiency or resistance to vasopressin causing poor reabsorption of water by the kidneys
What are the symptoms of diabetes insipidus?
- Extreme thirst (polydypsia)
- Dilute urine
What are the periop considerations for patients with diabetes insipidus?
Watch for electrolyte imbalances like high Na+ and low K+/Mg2+
What is diabetes mellitus?
Chronic disease caused by abnormal glucose metabolism that results in long-term morbidity
What organ is the primary source of endogenous glucose?
Liver
What is a normal Hemoglobin A1C?
A) Less than 6%
B) Less than 8 %
C) Less than 10%
D) Less than 15%
A. Less than 6%
What is the function of beta cells in the pancreas?
Secrete insulin when blood glucose levels are high
What is the function of alpha cells in the pancreas?
Secrete glucagon when blood glucose levels are low
What is the function of delta cells in the pancreas?
Secrete somatostatin upon food ingestion and inhibits insulin, glucagon, growth hormone, etc to extend the time over which food nutrients are put into the blood
What is the sympathetic innervation supplying the pancreas?
T5-T10, causes insulin inhibition and glucagon stimulation
What is the parasympathetic innervation supplying the pancreas?
Innervation via the vagus to cause insulin release
What is the function of insulin?
- Triggers glucose transport into the cells for usage by the cells
- Stimulates protein and lipid synthesis
Is insulin required for brain utilization of glucose?
No
What is the function of glucagon?
- Increases glucose output from the liver
- Stimulates glycogenolysis
- Stimulates gluconeogenesis
- Inhibits glycolysis
What causes diabetes mellitus?
Decreased secretion of insulin from beta cells or increased resistance of receptors to insulin caused by either heredity or obesity
What is Type I DM?
- Immune related destruction of beta cells
- Insulin dependent
What is Type II DM?
Insulin resistance, have normal to high plasma insulin levels but inappropriate for level of glucose
What is gestational diabetes?
Glucose intolerance that first develops during pregnancy
What is the classic triad of symptoms of diabetes melitus?
1) Polyurea
2) Polydypsia
3) Polyphagia (constant appetite)
What are the acute complications associated with diabetes mellitus?
- Diabetic ketoacidosis
- Hyperosmolar coma
- Hypoglycemia
What are the long term complications associated with diabetes mellitus?
- HTN
- CAD
- MI
- CHF
- Vascular disease
- Neuropathy
Patients with DM have a __ times greater risk of an MI perioperatively
20
What preop testing should be done to avoid a periop MI in patients with DM?
EKG
What symptoms of DM could indicate a difficult DL?
Stiff joint syndrome causes atlanto-occipital joint stiffness and possible TMJ stiffness
Diabetic Ketoacidosis (DKA) is more common in patients with Type 2 Diabetes.
A) True
B) False
B) False
What is the cause of diabetic ketoacidosis?
Decreased insulin activity causes the metabolism of free fatty acids and the accumulation of organic acid by products
What is often the first manifestation of type I DM in adolescents?
Infection
What are the clinical signs of diabetic ketoacidosis?
- Kussmal breathing
- Dehydration
- N/V
- BS 320-330
- Polyuria
- Ketones in urine
- Fatigue
- Altered mental status
What is the treatment of diabetic ketoacidosis?
- Correct hypovolemia with normal saline
- Correct hyperglycemia with insulin
- Correct electrolyte deficiencies
What is a hyperosmolar nonketotic coma?
When hyperglycemia diuresis results in dehydrations and hyperosmolality
What are the symptoms of hyperosmolar nonketotic coma?
- Glucose over 600
- No acidosis or ketones
- Thirst
- Confusion
What is the treatment for hyperosmolar nonketotic coma?
- Hypotonic saline
- Low dose insulin
What causes hypoglycemia?
Excessive insulin relative to carbohydrate intake
Which type of diabetes does hypoglycemia most often occur?
Type I
Hypoglycemia is defined as a blood glucose less than __ mg/dL
50
What are the symptoms of hypoglycemia?
- Catecholamine discharge causing agitation, diaphoresis, tachycardia
- Mental status changes
Which type of diabetes is managed with regular insulin therapy?
Type I
What is the only insulin that can be given IV?
Regular insulin
How soon before surgery should metformin be discontinued?
24 hours
Which insulin drug has a rapid onset?
Novalin
Which insulin drug is intermediate?
Humalin
Which drugs given to diabetics stimulates insulin secretion?
Sulfonylureas like tolazamide and tolbutamide
Which drugs given to diabetics inhibit gluconeogenesis?
Biguanidines
What biguanide is considered first line therapy in obese type II patients who dont respond to diet and exercise?
Metformin (glucophage)
What are the four major classes of oral hypoglycemic agents? What are their MOAs?
1) Secretagogues (sulfonylureas) - increase insulin availability
2) Biguanides (Metformin) - suppress glucose release
3) Glitazones - improve insulin sensitivity
4) Alpha glucosidase inhibitors (Acarbose) - delay GI glucose absorption
Hemoglobin 1Ac levels greater than __% indicate poor glycemic control
10
Patients with hypoglycemia may have drug interactions with which classes?
- Steroids
- Catecholamines
- Beta blockers
What are the risks during induction of hypoglycemic patients?
- Dramatic drop in BP
- Gastric aspiration risk
How can you assess for autonomic neuropathy of the parasympathetic nervous system in hypoglycemic patients?
Valsalva maneuver or watch for sinus arrhythmia
What is normal heart rate variability during voluntary deep breathing?
Greater than 10 beats per minute
When should you treat high glucose levels intraoperatively?
Greater than 150
How do you calculate the number of insulin units to give patients with high glucose intraop?
(Blood sugar-100)/40
Insulin administration will decrease what serum electrolyte?
K+
How often should you check blood glucose when administering insulin intraop?
Every hour
What is the starting infusion rate for insulin?
0.1 units/kg/hour
How much does 1 unit of insulin lower blood sugar?
25-30 mg/dL
Carcinoid syndrome is caused by tumors in the GI tract that release massive amounts of what substances?
- Serotonin
- Histamine
What are the symptoms of carcinoid syndrome?
- Flushing
- Diarrhea
- Hypotension
What are the anesthetic considerations for patients with carcinoid syndrome?
- A line
- Zofran
- Octreotide
What drugs commonly given by anesthetists can cause a carcinoid crisis?
- Succinylcholine
- Atracurium
- Epi
- Norepi
What are the 6 significant risk factors for a postoperative cardiac event?
1) High risk surgery
2) Ischemic heart disease
3) Creatinine over 2.0
4) History of TIA or CVA
5) Type I Diabetes
6) History of CHF
Patients having __ or more risk factors are considered at an elevated risk for a postop cardiac event
2
What are the indications for a pre-op 12 lead ECG?
- CAD
- PAD
- Arrhythmias
- Cerebrovascular disease
What pre-op test gives us a good assessment of left ventricular function?
Echo
A pre-op echo is reasonable for patients with what symptoms and medical histories?
- Dyspnea of unknown origin
- CHF with worsening dyspnea
- Previous LV dysfunction
ECG exercise testing requires the ability to exercise enough to get the heart rate up to __% of age predicted maximum
75%
What is the dipyridamole-thallium stress test?
Assess for at risk areas by redistributing myocardial perfusion
What is the range of positive predictive values for ischemic events with the dipyridamole-thallium stress test?
4-20%
What is the dobutamine stress echo?
Assess for new regional wall motion abnormalities with increased heart rate
What 3 components make up the preoperative cardiac assessment according to ACC/AHA guidelines?
1) Clinical predictors
2) Functional capacity
3) Surgical risk
What are considered “active cardiac conditions” according to ACC/AHA guidelines?
1) Recent MI
2) Decompensated heart failure
3) Significant arrhythmias
4) Severe valvular disease
What are considered high risk surgeries according to ACC/AHA guidelines?
1) Emergencies
2) Aortic and major vascular surgeries
3) Prolonged surgeries with large fluid shifts/loss
What are considered intermediate risk surgeries according to ACC/AHA guidelines?
1) Carotid endarterectomy
2) Head/neck surgeries
3) Intraperitoneal/intrathoracic
4) Orthopedic
5) Prostate
What are considered low risk surgeries according to ACC/AHA guidelines?
1) Endoscopic procedures
2) Superficial procedures
3) Cataracts
4) Breast
5) Ambulatory
What activities are considered 1 MET?
- Eat, dress, walk around house
- Walk 1 or 2 blocks on ground level
What activities are considered 4 MET?
- Climb 1 flight of stairs
- Walk on level ground at 4mph
- Heavy house work
- Golf
- Dance
What activities are considered 10 MET?
- Swim
- Run
- Aerobic exercise
When is CABG indicated according to ACC/AHA guidelines?
- Stable angina and L main stenosis
- Stable angina and 3-vessel CAD
- Stable angina and 2-vessel CAD with LAD stenosis and EF less than 50%
Use of beta blockers in patients with CAD has shown an increased risk of what periop events?
Bradycardia and stroke
Which beta blocker has been associated with an increased risk of stroke?
Metoprolol
Patients with __ or more RCRI risk factors may need to begin beta blockers before surgery
3
Why are ACE inhibitors usually held on the morning of surgery?
To prevent intraop hypotension
What AAR monitoring is necessary for all aortic cases?
- ASA standard monitoring
- Large IV access
- A line
What AAR monitoring is necessary for patients with good LV function?
Central venous line
What AAR monitoring is necessary for patients with poor LV function?
- PA catheter
- TEE
What are the renal affects caused by infrarenal aortic cross clamping?
- Reduction in renal blood flow
- Reduced GFR
What should be monitored during and after clamping of infrarenal aorta to assess renal function?
Urine output
What diuretics should be considered during an infrarenal aortic cross-clamping?
Mannitol and furosemide
What are the hemodynamic changes during clamping of the aorta?
Increase in catecholamines leading to venoconstriction which causes increased preload, afterload, and contractility
What are the hemodynamic changes after the unclamping of the aorta?
- Decrease myocardial contractility
- Central hypovolemia
- Decrease venous return
- Decrease cardiac output
- Hypotension
Neuraxial anesthesia with abdominal aortic surgeries for post op pain relief has been found to decrease what postop incidence?
MI
What IV access should be obtained for an infrarenal aortic endostent graft surgery?
- Large IV access
- A-line
What anesthetic techniques can be used for an infrarenal aortic endostent graft surgery?
- Local
- Regional
- General
What are the symptoms of anterior cord ischemia?
Loss of motor function, pain, and temperature sensation
What are the symptoms of posterior cord ischemia?
Loss of proprioception and fine touch
What are the hemodynamic changes associated with clamping of the thoracic aorta?
- Shift of blood volume to the brain
- Increased ICP
- Decrease spinal cord perfusion
What airway device should be used for an open thoracic aneurysm repair?
Double lumen ETT
A spinal drain is used during an open thoracic aneurysm repair to keep CSF pressure less than __ mmHg
10
What drugs should be administered during an open thoracic aneurysm repair for spinal cord protection?
Steroids
Carotid endarterectomies are more prevalent for patients with which risk factors?
- Angina
- HTN 180/110
- CHF
- A fib
- Over 75 y/o
- Diabetes
- Renal insufficiency
What are the standard monitoring used in carotid endarterectomies?
- Standard ASA
- 5 lead ECG
- A line
Patients that had an rSO2 decrease by more than __% presented with neurological symptoms
30
What are the advantages of regional anesthesia for a carotid endarterectomy?
- Can keep patient awake to monitor cerebral function
- Less hemodynamic variation
- No postop sedation to confuse evaluation
What are the advantages of general anesthesia for a carotid endarterectomy?
- No patient movement
- Control of airway
- Can control CO2
- Can provide HTN during clamping
What physiologic states can increase cerebral protection during carotid endarterectomies?
1) HTN
2) Hemodilution
3) Hypothermia
4) Normoglycemia
5) Normocarbia
What anesthetic drugs can increase cerebral protection during carotid endarterectomies?
1) Barbituates
2) Volatile agents
3) Propofol
What are the symptoms of hyperperfusion syndrome?
- Ipsilateral headache
- Seizures
- Focal neurologic signs
What factors increase the risk of hyperperfusion syndrome?
- Severe ICA stenosis
- HTN
- Contralateral ICA stenosis
How should perfusion pressure be maintained before and during aortic crossclamping?
Maintain high pressures
After aortic surgeries there should be close monitoring post-op for what issues?
1) Hypotension
2) Neck hematoma
3) Hyperperfusion syndrome