Truelearn

Question 1

What causes overdamping of pressure waveform?

Answer 1

factors that increase the compliance of or resistance within the circuit—such as the addition of stopcocks, air bubbles, or distensible tubing
(MAP) is generally preserved

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Question 2

What are the indication for hyperbaric oxygen therapy?

Answer 2

Gas-bubble disease (air embolism and decompression sickness)
Carbon monoxide poisoning
Infections (clostridial myonecrosis, other soft tissue necrotizing infections, refractory chronic osteomyelitis, intracranial abscess)
Acute tissue ischemia (crush injury, compromised skin flaps, central retinal artery or vein occlusion)
Chronic ischemia (radiation necrosis, ischemic ulcers)
Acute hypoxia (exceptional blood loss anemia when transfusion is unable to be given)
Acute thermal burn injury
Idiopathic sudden sensorineural hearing loss

Question 3

Does adding Epi to buvipicaine prolong it’s effect? explain?

Answer 3

No. It improves quality of the analgesia. Epi decreases overall blood loss at site of admin, reducing systemic absorption by decreasing blood flow. This effect is more pronounced with short or intermediate acting local anesthetics.which tend to be more hydrophilic and less preferentially bound to tissue proteins.

By contrast, longer-acting local anesthetics such as bupivacaine exhibit durations of effect that are less responsive to vasoconstrictive additives such as epinephrine.

Question 4

Indications for prophylactic antibiotics

Answer 4

Only patients who are undergoing dental procedures that “involve the manipulation of gingival tissue…periapical region of teeth, or perforation of the oral mucosa” are to be considered for prophylactic antibiotics

Only patients who are undergoing dental procedures that “involve the manipulation of gingival tissue…periapical region of teeth, or perforation of the oral mucosa” are to be considered for prophylactic antibiotics

Prosthetic cardiac valves, including transcatheter-implanted prosthetic valves
Patients with implanted prosthetic material, such as annuloplasty rings and artificial chordae tendineae
Patients with a history of infectious endocarditis
Patients with a history of unrepaired cyanotic congenital heart disease, including patients with a repair, but with a residual shunt or valvular regurgitation near an implanted patch or device
Patients with a history of cardiac transplantation who have a regurgitant valvular lesion due to a structurally abnormal valve

Question 5

Most effective anesthetic technique for FIRST stage of labor

Answer 5

lumbar sympathetic block
- L2 and L3. A lumbar sympathetic block interrupts the transmission of pain impulses from the cervix and lower uterine segment to the spinal cord

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First stage - regular contractions with dilation of cervix <10cm

Second stage - cervix fully dilated >10cm. ends with birth of baby

third stage- placenta

Question 6

Phosgene toxicity effects

Answer 6

colorless gas, smells like grass. causes significant pulmonary damage. Supportive care is tx. minimize inflammation

Question 7

Bronchial cuff is clamped on double lumen tube. which lung is down?

Answer 7

Left lung

Bronchial cuff is suppose to be in left main bronchus. Tracheal cuff will close air to right lung

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Question 8

What effect describes the hemoglobin oxygen dissociation curve caused by changes in carbon dioxide and pH?

Answer 8

Bohr effect

Chronic acid-base changes over 24-48 hours will alter levels of 2,3-DPG leading to a return to baseline of a shifted oxygen dissociation curve.

Question 9

What is the Haldane effect?

Answer 9

Describes how oxygen concentrations determine hemoglobin’s affinity for carbon dioxide.

Ex: high oxygen concentrations enhance the unloading of carbon dioxide.

Question 10

What principle described oxygen consumption relation to cardiac output?

Answer 10

Fick’s principle.relates oxygen consumption to cardiac output and the oxygen content difference between arterial and venous blood.

Question 11

Ficks principle equation

Answer 11

VO2 (oxygen consumption) = Q (cardiac output) x (arterial -venous)O2

Q = HR \* SV 
SV = EDV - ESV 

a = arterial O2 (left heart)
v = venous O2
difference in these is the oxygen delivered to tissues (which is used in the ETC)

Question 12

What is the chloride effect?

Answer 12

chloride shift refers to the reaction in which bicarbonate is exchanged for a chloride ion across the red blood cell membrane. Bicarbonate is formed by the reaction of carbon dioxide and water via carbonic anhydrase (carbonic acid is initially formed but readily dissociates into bicarbonate and hydrogen ions).

Question 13

how is CO2 transported in blood?

Answer 13

Dissolved CO2 in blood 7%
Binds to Hb 23%
covered to Bicarbonate in RBC (via carbonic anhydrase in RBC)

CO2 + H2O – HCO3 + H+

Question 14

What chemical controls autoregulation of hepatic blood flow?

Answer 14

Adenosine.

Question 15

Liver blood supply? Most oxygen content?

Answer 15

Hepatic artery 25% of blood flow, 50% oxygen supply

Splanchnic organs (intestines, stomach, pancreas, and spleen) 75% blood flow, 50% oxygen supply

Question 16

Respritory changes in pregnancy

Answer 16

Decreased

• Residual volume
• Expritory reserve volume
• (FRC = ERV + RV) also decreased

Increased

• Inspritory reserve volume
• Tidal volume

Closing capacity unchanged

Vital capacity = ERV+ IRV + TV unchanged

Question 17

What causes rightward shift in hemoglobin curve?

Question 18

What causes leftward shift in hemoglobin curve?

Answer 18

A leftward shift increases hemoglobin’s affinity for oxygen and reduces tissue delivery.

The following factors cause a leftward shift of the P50 of hemoglobin:
• Hypothermia
• Carbon monoxide
• Fetal hemoglobin (Hgb F)
• Methemoglobin
• Hypophosphatemia (seen in the critically ill)

Question 19

Late decelerations in pregnancy signify

Answer 19

Question 20

Management of late decelerations in pregnancy, first step and later

Answer 20

Reposition pt in lateral position

IV fluids if hypotensive, leg raise

Discontinue uterotonic drugs

Administer tocolytic if sustained uterine contractions

Question 21

Pt on low dose SQ Heparin (5000units BID or TID), how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?

Answer 21

4-6 hours

restart immediatly after

hold 4-6 hours before removing catheter

Question 22

Pt on HIGH dose SQ Heparin (7500-10,000units BID), how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?

Answer 22

Hold 12 hours AND normal coagulation status

Avoid restarting if catheter in place

Restart immediatly after catheter removal

Question 23

Pt on Theraputic dose SQ Heparin (>20,000units), how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?

Answer 23

Hold for 24 hours AND normal coagulation status

Avoid restarting is catheter in place

Restart immediatly after removal

Question 24

Pt on IV Heparin, how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?

Answer 24

Hold 4-6 hours AND normal coagulation status

Restart 1 hour after procedure

hold 4-6 hours prior to removal of catheter

restart 1 hour after removal

Question 25

Pt on prophylactic LMWH (daily), how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?

Answer 25

Hold for 12 hours prior to procedure restart after 12 hours if catheter in place Hold 12 hours before removing catheter restart after 4 hours AND no earlier than 12 hours after catheter placement

Question 26

Pt on Therapeutic LMWH, how long to hold prior to neuroaxial procedure; when to restart after procedure, when to hold before removing neuroaxial catherter removal?

Answer 26

Hold for 24 hours prior to procedure Avoid restarting if catheter in place Restart 4 hours AND no earlier than 24 hours after catheter placement

Question 27

What is Heliox used for? What is the mechanism?

Answer 27

Used to treat patients with airway obstruction such as that produced by postoperative stridor. ## Footnote Mixture’s lower density compared to oxygen alone, which increases the flow of gas across obstructed airways.

Question 28

How to treat stridor

Answer 28

* supplemental or humidified oxygen therapy * inspired racemic epinephrine * steroids * noninvasive positive-pressure ventilation modalities * helium-oxygen combinations * Intubation (last resort)

Question 29

What is Renauds number proportional to?

Answer 29

Re is directly proportional to gas density (ρ), gas velocity (v), and diameter (D) indirectly proportional to gas viscosity (μ).

Question 30

Most common cardiac manifestation of Rheumatoid artheritis

Answer 30

Mitral regurgitation is the most common Aortic valve disease, especially aortic regurgitation, is also often seen. Stenotic valve lesions are not typically associated with RA.

Question 31

Electrolyte abnormality associated with hyperventilation (respiratory alkalosis)?

Answer 31

Hypocalcemia. In response to alkalosis, hydrogen ions bound to negatively charged plasma proteins, such as albumin, are released. Calcium, being positively charged, can then bind to albumin and other proteins, thereby decreasing the serum calcium concentration (particularly the free/ionized, active fraction). This is the mechanism behind paresthesias that occur with hyperventilation. Hypokalemia. Hydrogen-potassium transporters pump hydrogen ions out of cells in the setting of alkalosis to restore physiologic pH. Simultaneously, potassium is pumped intracellularly to ensure electroneutrality. Alkalosis can cause hypophosphatemia. A rising cellular pH stimulates the glycolytic pathway, enhancing sugar-phosphate production. This triggers increased cellular uptake of phosphorus, thus decreasing serum phosphorus concentration.

Question 32

Management of Von Willebrand disease in pregnant women undergoing c-section. Which clotting factor is deficient? Indication for treatment?

Answer 32

von Willebrand factor serves as a carrier protein for factor VIII von Willebrand disease (vWD) who have a factor VIII level \>50% do not require treatment during labor or cesarean delivery. During pregnancy, there is an increase in the levels of factor VIII and von Willebrand factor (vWF) that normally corrects the deficiency seen in type 1. Desmopressin when factor VIII levels are \< 50% If pt doesnt respond, Humate-P or Alphanate can be used, which is a concentrate of factor VIII and vWF. If actor VIII is \< 50%, desmopressin should be administered for type 1, and factor VIII and vWF concentrates should be administered for types 2 and 3.

Question 33

IgA deficiency requiring transfusion, which type of transfusion is appropriate to minimize risk of anaphylaxis

Answer 33

Washed. preparation involves washing the RBCs to remove donor plasma until IgA levels are reduced \< 0.05 mg/dL

Question 34

Mechanism of hypoxic pulmonary vasoconstriction (HPV) during OLV

Question 35

Affect of NO and volatile anesthetics on hypoxic pulmonary vasoconstriction during OLV

Answer 35

Inhibits HPV

Question 36

Presentation of congenital diaphragmatic hernia, initial management

Answer 36

In addition to nonspecific features of neonatal **respiratory failure** including retractions, grunting, nasal flaring, and tachypnea, CDH may present with a barrel-shaped chest, a **scaphoid or sunken abdomen**, unilateral breath sounds, and **displacement of the heartbeat** due to visceral displacement and mediastinal shift. ETT, deliver low tidal volumes, low peak inspiratory pressures, permissive hypercapnia, and minimal supplemental oxygen to avoid further injury to the hypoplastic lung. (PPV with mask/t piece is contraindicated due to risk of risk of forcing air into the stomach or loops of herniated bowel within the thorax.

Question 37

unlateral cleft lip nerve block

Answer 37

Infraorbital nerve

Question 38

How do inhaled anesthetics prolong muscle relaxant effects (3 ways)

Answer 38

1. augmentation of the antagonist's affinity at the receptor site 2. central effects on alpha motor neurons and interneuronal synapses, 3. nhibition of postsynaptic nicotinic acetylcholine receptors.

Question 39

Which drug used to treat hypotension in critical aortic stenosis?

Answer 39

Phenylephrine In severe aortic stenosis, cardiac output is relatively fixed. The heart cant compensate for any vasodialation (decreased SVR). Coronary perfusion suffers bc decreased diastolic pressure. Goal is to maintain normal to slower HR Hypertrophic heart is at risk for ischemic changes even if no CAD (increased oxygen demand due to hypertrophied left ventricle). Atrial kick also contributes a lot to maintain the end diastolic volume.

Question 40

Normal AV area

Question 41

Severe aortic stenosis is defined as

Answer 41

Transvalvular pressure gradients higher than 40 mm Hg and a valve area less than 1 cm2 are characteristic of severe aortic stenosis.

Question 42

What is Dalton's law

Question 43

Boyle's law

Answer 43

the pressure of a gas is inversely proportional to its volume at a constant temperature P1V2 = P2V2 P

Question 44

Placenta delivery time in absence of hemorrhage (In presence of hemorrhage?)

Answer 44

60 minutes Postpartum hemorrhage usually results from: uterine atony, retained placenta, genital tract trauma, or coagulation disorders. Retained placenta is the second most common cause of PPH placenta that has not been expelled within 30 minutes after delivery of a baby. The guidelines recommend, in the absence of hemorrhage, waiting an additional 30 minutes after diagnosis to allow for spontaneous expulsion. If this does not occur, controlled cord traction may be the first step in helping to expel the placenta. The addition of oxytocin may be beneficial, especially if the uterus is atonic, because uterine atony may result in failed separation/expulsion. Ergot alkaloids (e.g., methylergonovine) are not recommended, as they may cause tetanic uterine contractions, which can delay placental expulsion and make manual extraction more difficult. Additionally, prostaglandin E2 is not recommended, because it is associated with an increase in cardiac events.

Question 45

which pediatric neurologic disorders would volatile anesthetics produce an increased pharmacodynamic effect?

Answer 45

Cerebral Palsy (CP) -- more sensitive to the effects of volatile anesthetics, and a lower minimum alveolar concentration (MAC) may be required to achieve surgical anesthesia

Question 47

Mechanism behind tachycardia and palpitations in untreated Graves' disease

Answer 47

Hyperthyroidism is associated with **upregulated expression of beta1-adrenergic receptors on cardiomyocytes**, which increases cardiac sympathetic sensitivity with an increase in heart rate. upregulation of sodium-potassium pump expression associated with hyperthyroidism drives a significant increase in the basal metabolic rate, producing classic clinical symptoms such as unintended weight loss and heat intolerance.

Question 48

Test commonly used for high dose heparin administration and evaluates the intrinsic and final common pathways of the coagulation system?

Answer 48

activated clotting time (ACT) is commonly used to evaluate the anticoagulant effect of high dose heparin administration Whole blood is added to a tube that contains an activator substance (celite or kaoline) and time to clot formation is measured. normal ACT is around 107 seconds. A value between 400-480 seconds is typically required to initiate cardiopulmonary bypass. Hypothermia, hemodilution, thrombocytopenia (\< 30-50,000/uL), and platelet inhibitors also prolong the ACT.

Question 49

Decreased maximum amplitude (MA) primarily provides evidence of

Answer 49

thrombocytopenia and/or platelet dysfunction

Question 50

Which are the most resistant evoked potentials to the effects of volatile anesthetics?

Answer 50

Brainstem auditory evoked potentials (BAEPs) hearing sounds, such as talking, music, or conversations, is one of the most commonly reported experiences for patients with intraoperative awareness.

Question 51

Nerve that supplies sensory innervation to the laryngeal mucosa ABOVE the vocal cords?

Answer 51

Internal branch of the superior laryngeal nerve provides sensory innervation to the laryngeal mucosa superior to the vocal cords.

Question 52

What does the External branch of the superior laryngeal nerve innervates? Internal branch?

Answer 52

External branch of the superior laryngeal nerve provides MOTOR innervation to the cricothyroid muscle. Internal - sensory above the vocal cords

Question 53

recurrent laryngeal nerve provides ?

Answer 53

recurrent laryngeal nerve provides sensory innervation to laryngeal tissue below the vocal cords.

Question 54

Activated clotting time (ACT) is used to monitor

Answer 54

Activated clotting time (ACT) is used to monitor the effect of high-dose UFH therapy in situations where aPTT is not clinically useful or takes too long (e.g. cardiopulmonary bypass).

Question 55

molecular mechanism by which inhaled beta-agonist agents lead to bronchodilation? cAMP vs cGMP

Answer 55

cAMP Beta-2-adrenergic receptor activation causes bronchodilation mediated by the intracellular second messenger cyclic adenosine monophosphate (cAMP).

Question 56

MOA of Atropine

Answer 56

anticholinergic that indirectly increases the heart rate by blocking parasympathetic innervation to the heart.

Question 57

anti-hypertensive medication that can cause direct cerebral vasodilation

Answer 57

Nicardipine. cerebral autoregulation occur at MAP values of approximately 60 and 160 mmHg Calcium channel blockers, nitroglycerin, hydralazine, nitroprusside, and adenosine also cause direct cerebral vasodilation and may decrease cerebral vascular resistance to a greater extent, increasing CBF higher than what would be expected by the autoregulation mechanism alone.

Question 58

Propofol infusion syndrome (PRIS) signs and symptoms... treatment?

Answer 58

Propofol infusion syndrome is a rare complication of prolonged, high-dose propofol administration. Signs may include metabolic lactic acidosis, cardiac failure, renal failure, rhabdomyolysis, hyperkalemia, hypertriglyceridemia, hepatomegaly, and pancreatitis. Stop prop and supportive tx.

Question 59

bicuspid aortic valve, patent ductus arteriosus, and epistaxis associated with

Answer 59

Coarctation of the aorta

Question 60

nitric oxide causes smooth muscle relaxation via which pathway (cAMP vs cGMP)?

Answer 60

cGMP intracellular cyclic GMP has been associated with inhibited leukocyte adhesion, platelet activation, as well as leukocyte proliferation.

Question 61

Pt with COPD may develop acutely worsened hypercapnia with the administration of supplemental oxygen because of

Answer 61

increase in ventilation/perfusion (V/Q) mismatch (not because of central respiratory drive) Hypoxic pulmonary vasoconstriction (HPV) redistributes pulmonary blood flow to areas of the lung with higher alveolar oxygenation content. O2 inhibits HPV, allowing blood (perfusion) to those alveoli with retained CO2... this high concentration of CO2 in alveoli prevents CO2 in blood to be exchanged.

Question 62

Meperidine works on the _____ opiod receptor when do we use meperidine?

Answer 62

Kappa Used as antishivering causes accumilation of proconvulsant metabolites in renal falure patients

Question 63

U1 receptor produces

Answer 63

analgesic and physical dependence properties of most opioids

Question 64

U2 receptors results in

Answer 64

respiratory depression, miosis, euphoria, decreased gastrointestinal motility, and physical dependence.

Question 65

What symptoms are most characteristic of myofascial pain syndrome?

Answer 65

Palpable taut bands with radiating pain arising from a trigger point, the trigger point is felt as a palpable taut band.

Question 66

management of myofascial pain syndrome?

Answer 66

repeated applications of a cold spray over the trigger point in line with the involved muscle fibers, followed by a gentle massage of the trigger point and stretching of the affected muscle. Another treatment is local anesthetic injection or dry needling of the trigger point.

Question 67

Ketamine EEG patern

Answer 67

Active EEG patern: fast oscillations in the high beta range to low gamma range.

Question 68

Ketamine affect on cerebral metabolic rate of oxygen and cerebral blood flow.

Answer 68

increased CMRO and CBF

Question 69

Dexmedetomidine MOA

Answer 69

presynaptic α2 adrenergic receptors, hyperpolarizing neurons located in the locus coeruleus, and decreasing norepinephrine release from neurons projecting from the locus coeruleus to the preoptic area of the hypothalamus

Question 70

Dexmedetomidine MOA similar to what type of sleep patten, why?

Answer 70

nonrapid eye movement (NREM) sleep EEG pattern observed during stage II nonrapid eye movement sleep

Question 71

formula for standard error

Answer 71

SE = Standard deviation / sqrt (sample size) SE = SD / sqrt (n)

Question 72

Vasopressin MOA WHich patients to avoid in ...

Answer 72

V1 receptor = increase SVR V2 = increase water reuptake via aquaporin channels = increase bllood volume **Avoid in coronary artery disease**, administration of vasopressin can cause myocardial ischemia due to the vasoconstriction of stenotic areas thus caution must be taken in this patient population. vasopressin safe in renal dysfunction and liver failure. Vasopressin increased ciculating vWf andf FVIII DDAVP - doesnt cause systemic htn

Question 73

coronary artery MOST LIKELY to be implicated in acute onset bradycardia

Answer 73

Right Coronary Artery can affect the conduction system, which can lead to significant hemodynamic alterations and bradyarrhythmias.

Question 74

Cause for unilateral block after epidural

Answer 74

epidural catheter that is located laterally in the epidural space, inadequate local anesthetic the presence of the plica mediana dorsalis (midline fold on the dura mater that extends to the ligamentum flavum)

Question 75

at what point in cerebral blood flow does irreversible brain damage begin to occur

Answer 75

Irreversible brain damage is seen at flow of 6-12 mL/100 g/min. Ischemia begins at 20 mL/100 g/min. Average CBF in the normal brain is 50 mL/100 g/min

Question 76

Donepezil causes \_\_\_\_\_\_\_\_relaxation after succinylcholine and show ___________ resistance to nondepolarizing muscle relaxants. Mechanism?

Answer 76

Donepezil is a reversible, non-competitive inhibitor of acetylcholinesterase which can cause increased availability of acetylcholine at neuromuscular junctions. increased presence of acetylcholine, patients on donepezil will have **prolonged relaxation after succinylcholine** and show **increased resistance to nondepolarizing muscle relaxants.** Some sources recommend that donepezil be held 2-3 weeks prior to surgery.

Question 77

congenital diaphragmatic hernia vent manamgement

Answer 77

Gentle ventilation" with _permissive hypercapnia_ using a low tidal volume strategy, PIP \< 25 cm H20, and FiO2 + PEEP adjustment to maintain preductal SpO2 of **90-95%**

Question 78

spine block with highest chance for intravascular injection

Answer 78

Cervical spine facet injections carry a higher risk of intravascular complications. This is due to the vertebral artery lying just lateral to the cervical facet joint.

Question 79

Anesthetic considerations for cushings syndrome patients

Answer 79

blood pressure regulation (these patients are typically hypertensive) glucose control, balancing electrolytes (often hypokalemia), and positioning (due to osteopenia).

Question 80

Indications for Retrograde cardioplegia over Anterograde cardioplegia

Answer 80

``` diffuse obstructive coronary artery disease (CAD) aortic insufficiency (AI), surgeries involving significant manipulation of the aortic root or coronary ostia. ```

Question 81

How is antegrade cardioplagia administered?

Answer 81

via a small-bore catheter or needle in an antegrade fashion at the aortic root or directly into the coronary arteries.

Question 82

Why is duplicated or persistant left-sided SVC contraindicated for retrograde cardioplagia?

Answer 82

duplicated SVC, which is thought to arise from a failure of the left anterior cardinal vein to involute during embryologic development, typically serves the same function as the left brachiocephalic vein but empties into an enlarged coronary sinus rather than the right atrium. Retrograde infusion into the coronary sinus in a patient with a duplicated SVC would potentially result in **systemic** (rather than solely myocardial) distribution of cardioplegia solution.

Question 83

Treatment for vasospastic angina (transient episodes, nausea, occur at rest)

Answer 83

Calcium Channel Blockers (nicardipine) (nitrates are second line - produce tolerance with repated use)

Question 84

How to prevent febrile blood transfusion reaction

Answer 84

Leukoreduction involves the reduction of white blood cells (WBC) from the red blood cells (RBC) to be transfused. Leukoreduction reduces risk of HLA alloimmunization, febrile reaction, and CMV transmission. IL-1 released during storage stimulates prostaglandin E2 causing fever.

Question 85

Blood Irradiation with 2.500 cGY pevent what reaction?

Answer 85

Irradiation with 2,500 cGY damages the WBC DNA which prevents a proliferative response to the recipient's tissues. It is used to **prevent graft versus host disease** especially in those who are immunosuppressed.

Question 86

What type of blood is used for IgA deficiency?

Answer 86

Washed Washing with saline is performed for blood to be used in patients with a history of allergic transfusion reactions such as IgA deficiency.

Question 87

Noonan syndrome

Answer 87

Question 88

Causes of citrate toxicity

Answer 88

Metabolic alkalosis Hypocalcemia Hyperventilation (alkalosis)

Question 89

Function of citrate

Answer 89

Citrate used as an anticoagulant becuase it chelates ionized calcum Calcium initiated clotting (thus inhibition of calcium in stored blood products through citrate chelation helps prevent clotting of the stored cells.)