MM Lightning Bolts Flashcards
Describe the murmurs heard, and specify the stethoscope location where they are best heard, if the patient has AS?
Systolic murmur at the 2nd right intercostal space with transmission to the neck often mimicking a carotid bruit
Name the organs in the VRG. What percent of CO goes to each of these organs?
VRG: Brain, Kidneys, Liver, Heart, Digestive Tract, and Endocrine tissue.
25% of CO to Liver; 5% Heart; 15% Brain; 20% Kidneys; 100% Lungs
What nerves carry afferent and efferent signals of the Bainbridge reflex?
Stretch (in RA) receptors send afferent signals to the medulla via the vagus
Efferent signals travel form the medulla via sympathetic nerves
What does the Bainbridge reflex help prevent?
Helps prevent damming up of blood in veins, atria, and Pulmonary Circulation.
What happens with the Bainbridge reflex?
Increases HR up to 75% and Increases contractility
The lungs have a dual blood supply, bronchial arteries and pulmonary arteries.
Where do the bronchial arteries arise and which lung tissues are supplied by bronchial arteries?
The bronchial arteries arise from the descending thoracic aorta and supply the bronchi and bronchioles.
Also supply supporting tissue such as nerves, pulmonary vessels, and visceral pleura. (High Pressure, Low Flow)
The lungs have a dual blood supply, bronchial arteries and pulmonary arteries.
Where do pulmonary arteries arise and what lung tissues are supplied by pulmonary arteries?
Arise from the RV and branch into R and L.
Supply venous blood to structures distal to the terminal bronchioles.
Low Pressure, High Flow
Describe the venous drainage of the lungs
Drainage occurs via bronchial, azygous, hemiazygos, and intercostal veins-> then drain into brachiocephalic veins of the neck -> finally the SVC
Where do preganglionic parasympathetic nerves originate?
From Nuclei of CN III, VII, IX, and X in the brainstem (3, 7, 9, 10)
Also from S2-S4. (AKA Craniosacral Division)
How much cerebrospinal fluid is produced per day?
500-750 mL/day (15-30mL/hr)
Myasthenia Gravis is characterized by what symptoms?
Characterized by weakness and fatigue of skeletal muscle. Can be asymmetric, confined to one group of muscles, or generalized.
What is the cause of Myasthenia graves symptoms?
Caused by autoimmune destruction of the nicotinic AcH receptors at the neuromuscular junction
Identify the biochemical triad that defines diabetic keto acidosis
Ketonemia,
Hyperglycemia,
Acidemia
What are the diagnostic criteria for diabetic ketoacidosis?
Diagnostic criteria include
- Ketonemia or ketonuria;
- BG > 250 mg/dL or known DM;
- Serum BiCarb < 18mmol/L or arterial pH < 7.3
It is generally recommended to cancel non urgent or elective surgery in the patient with DM if the serum glucose rises above what value?
If there is an acute rise above 400 mg/dL
Describe an individuals fluid and electrolyte status during diabetic keto acidosis?
Dehydration and hypovolemic shock from hyperglycemic osmotic diuresis
Compensatory hyperventilation (kuss maul)
Life threatening electrolyte depletion (hypokalemia & hypophosphatemia)
Anion gap > 10
An important early step in hemostasis is vasoconstriction of damaged vessels.
Platelets play a key role in this initial vasoconstriction by release of what substances?
Vascular contraction is a result of autonomic reflexes and the release of thromboxane A2 and ADP from platelets.
The endothelium releases many procoagulant factors following vascular injury: Name two key procoagulants released by the endothelium
Procoagulant factors release by the endothelium include Tissue factor (Factor III), and Factor VIII:vWF (von Willibrands Factor)
In addition to its role in early vasoconstriction, thromboxane A2 plays a key role in activation and aggregation of platelets. Describe the action of TxA2 in activation and adhesion of platelets
Platelets are activate by ADP and TxA2. They are ligand for GPCR’s that trigger signal transduction pathways leading to expression of GPIIb/IIIA receptors (Fibrinogen receptors) on platelet surface. TxA2 amplifies platelet agonist such as thombin (IIa) and ADP.
If their immune system overreacts to an allergen, a hypersensitivity reaction occurs.
Immune-mediated hypersensitivity reactions are classified into four groups by mechanism of act: list each type of allergic reaction and give a one sentence description of the reaction
Type I: Anaphylactic or immediate-type hypersensitivity reactions
Type II: Cytotoxic reactions (antibody-dependent cell-mediated cytotoxicity)
Type III: Immune complex reactions that produce tissue damage by deposition of immune complexes
Type IV: Delayed type hypersensitivity reactions resulting from the interaction of sensitized lymphocytes with specific antigens
Describe Type I allergic reactions: include participating cells and antibody and list common examples
An allergen interacts with IgE antibodies on mast cells or circulating basophils to trigger mediator release.
The key mediator is histamine.
Example of Type I reactions include allergic rhinitis, extrinsic asthma, and anaphylaxis
Describe Type II hypersensitive reactions: include participating cells and antibodies and list common examples
IgM and IgG mediated against antigens on the surface of foreign cells or extracellular tissue components.
Cell damage is produced by (1) direct cell lysis after complete complement cascade activation, (2) increased phagocytosis by macrophages, or (3) Killer T-Cell lymphocytes producing antibody dependent cell mediated cytotoxic effects.
Examples: ABO-Incompatability, Drug-induced immune hemolytic anemia, HIT, Myasthenia Gravis, and Goodpasture’s syndrome
Describe Type III allergic reactions, participating cells and antibodies and common examples
Result from circulating soluble antigens and antibodies that bind to form insoluble complexes which then deposit in the micro-vasculature.
Mechanism of tissue injury involves activation of complement and recruitment of phagocytes.
Examples: SLE, RA, glomerulonephritis and classic serum sickness
Describe Type IV allergic reactions, participating cells and antibodies and common examples
Result from sensitized lymphocytes with specific antigens.
Cytotoxic T-Cells are produced specifically to kill target cells that bear antigens identical with those that trigger the reactions.
Examples include tissue rejection, graft-vs-host, contact dermatitis, tuberculin immunity, and Johnson-Stevens syndrome. Another form is granulomatous hypersensitivity such as TB, Sarcoidosis, and Crohn’s disease.
What is anaphylaxis?
A severe, generalized, life-threatening immediate hypersensitivity reaction marked by interstitial edema -particularly laryngeal edema- bronchospasm, and CV collapse.
How does non-immune mediated anaphylaxis compare with anaphylaxis?
(aka anaphylactoid reaction) The triggering antigen directly stimulates mast cell and basophils; NO IgE mediated trigger. Symptoms are less severe.
Where is the J-Point in the ECG waveform?
The point where the QRS complex ends and the ST segment begins
How is the J-Point used in ECG interpretation?
ST segment changes are measured lead voltage at 60 to 80 milliseconds after the J-Point to the isoelectic value
What features uniquely identify LBBB?
(1) Broad, notched R wave in left side leads
(2) Deep S waves in the right precordial leads
(3) absent septal Q waves
What features uniquely identify RBBB?
(1) Prominent notched R-wave with “M” pattern and rsr’, rsR’ or rSR’ on the right side leads (V1)
(2) wide S on left side leads (V6)
Which is more prevalent, RBBB or LBBB? Which is more ominous?
RBBB is more prevalent. LBBB is more ominous and is associated with ischemic heart Dz, HTN, and valvular Dz.
What is one concern with PA catheter placement in a patient with LBBB?
May precipitate a RBBB which would lead to complete heart block (3rd degree heart block)
Which volatile agents most depress the baroreceptor reflex and which least depress it?
Most depressed by Halothane and Sevo.
Least depressed by Iso and Des.
What are the minimum alveolar concentration (MAC) requirements for a full-term infant, compared to the adult?
MAC for a full term infant is the same as for an adult
At what age is the MAC highest? Which agent is the exception to this rule?
At 6 months, MAC is 50% greater that adult (1.5x). The exception to this rule is sevoflurane which has a MAC value that is greatest in the neonate (3.3%).
Which IV sedative hypnotic inhibits platelet aggregation?
Propofol inhibits platelet aggregation that is induced by TxA2 and platelet activation factor.
List the local anesthetics that are amides?
(two "i") Lidocaine, Prilocaine, Mepivacaine, Bupivacaine, Levobupivacaine, Ropivacaine
The alpha-2 adrenergic receptor agonist, clonidine, acts where centrally to produce what therapeutic effect?
Stimulation of Alpha-2 receptors in the Vasomotor center of the medulla to inhibit SNS outflow. (Decreases BP)
Alpha-2 adrenergic receptor agonists antagonize the SNS peripherally. How?
Alpha-2 receptors are found on the surface membrane of NE containing presynaptic nerve terminals of sympathetic postganglionic neurons
Patient is on continuous sodium nitroprusside drip with the following ABG: pH= 7.21, PaCO2= 32mmHg, PaO2= 104mmHg, Base Excess= -10mEq/L. What is your next action?
Turn off Drip. ABG suggest cyanide toxicity. BE suggest metabolic acidosis, Low PaCO2 demonstrates partial respect compensation.
Define autacoid and list examples
They are biological factors that act like hormones (they have paracrine effect).
Produced in minute quantities and have only brief local effects.
Examples: eicosanoids, angiotensin, NO, kinins, histamine, serotonin, and endothelins.
What are eicosanoids?
Signaling molecules derived from omega-3 and omega-6 fatty acids including arachidonic acid.
Examples: prostaglandins, thromboxane, leukotrienes, and lipoxins.
They are not stores but are stored on demand.
How are prostanoids related to eicosanoids?
Prostanoids are metabolic derivatives of arachidonic acid (a category of eicosanoids). Examples: prostaglandins, prostacyclin, & thomboxanes.
Arachidonic acid, an omega-6 fatty acid, is liberated from membrane phospholipids by the action of what enzyme?
Phospholipase A2 (PLA2), a calcium-dependent enzyme, acts upon membrane phospholipids to release arachidonic acid. This is the rate limiting step in eicosanoid synthesis.
Which prostanoid is implicated in the rebound prothrombotic state often seen following discontinuation of anti platelet therapy?
An increase in TxA2 activity is seen during rebound period.
Name two prostanoids that are potent inhibitors of platelet aggregation and thus promote and maintain an anti thrombotic state in vessels?
Prostacyclin (PGI2) and PGD2 along with NO are released by vascular endothelium.
Which prostanoid produces vascular smooth muscle contraction and is thus a potent vasoconstrictor?
TxA2
List two prostanoids that cause bronchodilation and three that cause bronchoconstriction.
- Bronchodilation: PGE2 & Prostacyclin (PGI2)
- Bronchoconstriction: PGF2a, PGD2, & TxA2
How are leukotrienes related to eicosanoids?
Leukotrienes are metabolic derivatives of arachidonic acid (produced by LOX)
What action do leukotrienes (LK) have on the lungs? What cells synthesize and release LTs?
Activated mast cells and basophils synthesize/release LK.
LK evoke inflammatory response in the lungs including intense bronchoconstriction and increase pulmonary vascular permeability.
They also promote eosinophil degranulation and attract neutrophils.
What is another name for the mixture of leukotrienes C4, D4, and E4?
The classic slow reacting substance of anaphylaxis (SRS-A)
Which herbal supplement is a potent inhibitor of Thromboxane synthetase and thus has synergistic effects with other anti platelet agents?
Ginger: increases bleeding time and morbidity
Which dopamine antagonist is the only FDA-approves agent for treatment of diabetic gastroparesis?
Metoclopramide -> Cholinergic stimulation
List seven common adverse effects of metoclopramide?
(1) Treatable hypotension and tachycardia (most common)
(2) Sedation
(3) Restlessness
(4) Extrapyramidal symptoms
(5) ABD cramping after rapid injection
(6) Inhibition of plasma cholinesterase
(7) Galactorrhea
State four contraindications to administration of metoclopramide?
(1) Parkinsons Dz
(2) Restless Leg
(3) Movement disorders related to dopamine inhibition or depletion
(4) Intestinal obstruction
For what conditions are Alpha-Glucosidase inhibitors administered?
Insulin resistance and hyperglycemia in metabolic syndrome, DM-II, & obesity
How do Alpha-Glucosidase inhibitors work?
Decrease postprandial carb digestion and absorption
List the most common side effects of Alpha-glucosidase inhibitors?
Flatulance, ABD cramping, and diarrhea
Bleomycin is toxic to what body organ?
Pulmonary system
Why does bleomycin accumulate in the lungs?
The enzyme that inactivates bleomycin, hydrolase, is relatively deficient in lung tissue.
Antiemetic agents typically block which receptors?
(1) Dopamine receptors (D2)
(2) Histamine receptors (H1)
(3) Muscarinic AcH receptors
(4) Serotonin receptors (5-HT3)
(5) GABA(A) receptors
(6) Neurokinin-1 Receptors (NK1)
Correlate the clinically used antimemetics with their primary receptor
D2: Metoclopramide, droperidol, haloperidol, alizapride, perphenazine, prochlorperazine
H1: Dimenhydrinate, diphenhydramine, cyclizing, Promethazine
Muscarinic: Hyoscine
Serotonin receptors (setron): Odansetron, Dolasetron, granisetron…..
GABA(A): Midazolam, Diazepam, Lorazepam
NK1: Aprepitant
What effect does hypothermia have on gas solubility?
Causes an increase in gas solubility
Define the inverse square law
The strength of emanating energy is inversely proportional to the square of its distance from the source (Isaac Newton)
Occupational exposure to radiation comes primarily from X-Rays scattered by the patient and the surrounding equipment, rather than directly from the X-Ray generator itself.
State 4 methods to minimize exposure to scattered radiation
(1) Limit Duration
(2) Increase Distance
(3) Deflect: i.e. Protective shielding
(4) Dosimeter to monitor exposure
What is the minimum safe distance from the X-Ray source
6 feet (and behind or to the side)
What is the annual dose limit for occupational exposure to radiation? The lifetime dose limit?
50 mSv/yr (5 rem) or 10 mSv (1 rem) x age in years
What is daltons law?
Law of partial Pressure: Total Press = P1 + P2 + P3……
If atmospheric pressure is 710mmHg and the O2:N2O delivery is 2L:4L, what PP of O2 and what PP of N2O are delivered to the patient? Whose law permits these calculations?
1/3 x 710 mmHg = O2
2/3 x 710 mmHg = N2O
Daltons Law
In which publication is the purity of medical gases specified and who enforces purity of gases?
US Pharmacopoeia and the FDA
Which US government agency regulates matters affecting the safety and health of employees in all industries?
Department of Labor (DOL)
Which two executive-branch agencies were created to carry out the provisions of OSHA?
(1) NIOSH (part of CDC)
2) OSHA (part of DOL
What volume of anesthetic vapor is produced by 1 mL of volatile anesthetic liquid?
1mL of liquid = ~200mL of anesthetic vapor at 20 C and 1 atm
Describe SIMV
Intermittent mandatory breaths are given in synchrony with and triggered by the patients spont. efforts
Is SIMV pressure or volume mode? What aspect of ventilation is detected to trigger synchronization with the patient ventilatory effort?
either pressure or volume cycled. Trigger window controls amount of time vent is sensitive to spont. breaths. Senses neg pressure of spont breath.
Compare and contrast the Effects of IV vs IHA on sensory evoked potentials
(1) IHA’s Generally have more depressant effect that IV agents
(2) Combinations of drugs produce additive effects
(3) Prop and thiopental attenuate the amplitude of all evoked potentials but do not obliterate them
(4) Opioids and Benzos have negligible effects
(5) Ketamine and Etomidate enhance the quality of signals in patients with weak baseline SSEP signals
Rank the three major sensory evoked responses- SSEP, VEP, and BAPE - based upon sensitivity to anesthetic agents
BAEP (Barely)
Somatosensory (Somewhat)
Visual (Very)
Describe the placement of the 5 lead ECG cables?
Limb electrodes on corresponding limb (LA, RA, LL, RL) with a 5th chest electrode placed in any of the standard precordial (V1-V6) locations
Describe the proper placement of RA, LA, LL, and RL electrodes according to the Mason-Likar lead position scheme
RA: Over the outer RT clavicle
LA: over the outer LT clavicle
LL: Placed near the left iliac crest or midway b/w the costal margin and LT iliac crest alone the anterior racial line
RL: Placed at an convenient location on the body
Which unipolar lead in the 5-Lead monitoring system is preferred when arrhythmias are anticipated? Which unipolar leads are preferred for monitoring ischemia?
V1 for arrhythmia.
V3-V5 for ischemia
What advantage does CO2 monitoring have over pulse oximetry or VS monitoring?
Detects acute, complete airway obstruction and extubation more rapidly
What issues may increase the Beta angle of the CO2 waveform? Decrease the Beta angle?
Increase: rebreathing (CO2 absorbent issue, malfunctioning unidirectional valve)
Decrease: if the slope of phase III is decreased
Why might low or poor perfusion states interfere with accurate pulse oximeter readings?
They require adequate pulsation to distinguish light absorbed from arterial blood from venous blood and tissue light (plethysmographic analysis)
List two factors that lead to falsely HIGH pulse oximeter readings
Carboxyhemoglobin and methemoglobin ( when true SaO2 < 85%)
Explain how the presence of methemoglobin can lead to both falsely high and falsely low pulse oximeter readings
Absorbs both 660 and 940 nm so the pulse ox detect equal amounts of oxygen and deoxy-hemoglobin (readings of 80-85%)
List 5 factors that generally have no significant effect on pulse oximeter readings
(1) Polycythemia
(2) Skin Pigmentation
(3) Alternate hemoglobins
(4) Red henna dye
(5) Jaundice
Define MET
Metabolic Equivalent is defined as the amount of oxygen consumed while sitting at rest. They are used to evaluate functional capacity and reserve.
Correlate equivalent level of activity with MET 1-4
(1) eating, working at a computer, or dressing
(2) Walking down stairs, walking in your house, or cooking
(3) Walking one or two blocks on level ground
(4) Raking leaves, gardening
Correlate equivalent level of activity with MET 5-8
(5) climing one flight of stairs, bicycling, or dancing
(6) playing golf, or carrying golf clubs
(7) playing singles tennis
(8) rapidly climbing stairs or jogging
Correlate equivalent level of activity with MET 9-12
(9) Jumping rope slowly or moderate cycling
(10) swimming quickly, running, or jogging briskly
(11) cross country skiing or playing full court basketball
(12) running rapidly for moderate to long distances
Define the physical status index “ASA PS class 6.”
A declared brain dead patient whose organs are being removed for donor purposes
How much dextrose is in a 1 L bag of D5W? What is the dextrose concentration (mg/mL)?
50 grams of dextrose/L
or
50mg/mL
In addition to sodium and potassium, what three electrolytes does Normosol-R contain?
Na 140 mEq/L K 5 mEq/L Mg 3 mEq/L Acetate 27 mEq/L Gluconate 23 mEq/L
List 4 reasons why dextran are of limited use nowadays?
(1) Antithrombotic effects, particularly inhibition of platelet aggregation
(2) interference with blood cross matching- dextran coat RBC membranes
(3) Anaphylactic and anaphylactoid reactions
(4) Renal Dysfunction resulting from osmotic nephrosis
Which blood components are found in pRBC’s?
Contains RBCs in anti coagulated plasma. contains citrated phosphate dextrose adenine-1 (CPDA-1)
The addition of adenine to pRBC’s stored in CPD extend extend the storage time from ____ days to _____ days
From 21 to 35 days
Name three preservatives that extend the storage time of pRBC’s form 35 to 42 days
As-1 (adsol)
AS-3 (Nutricel)
AS-5 (Optisol)
Describe the biochemical alterations of stored blood
Acidic,
Hyponatremic,
Hyperkalemic,
Hypoglycemic plasma (inc lactate) with increased free HgB
Decreased 2-3 DPG
Which blood components are present in FFP?
ALL clotting factors, naturally occurring inhibitors of coagulation, and antithrombin
Which blood components are present in Cryoprecipitate?
Contains concentrated factors I, VIII, vWF, XIII, Fibronectin
Which blood product contains the greatest concentration of fibrinogen (Factor I)?
Cryo 15g/L > FFP 2.5g/L
State the threshold for fibrinogen replacement?
Less than 80-100 mg/dL
How many bags of cryo constitute a single dose? What is the expected fibrinogen increase after a single dose?
A single dose = 5 bags of cryo
Raises fibrinogen by 50 mg/dL
According to the ASA’s 2006 updated practice guidelines, at what hemoglobin level is RBC transfusion rarely indicated? At what level is it always indicated?
Rarely >10 g/dL
Always <6 g/dL
According to the ASA’s 2006 updated practice guidelines, what factor justifies RBC transfusion when HgB levels are intermediate (6-10 mg/dL)?
Should be based on patients risk of complications of inadequate oxygenation
List four (4) variations of head-elevated surgical positions
(1) sitting, including lounge chair and beach chair variations
(2) supine- tilted head up
(3) lateral- tilted head up (aka park bench)
(4) Prone- tilted head up
VAE is the most feared complication of head up surgical positions. Edema of the face, neck, and tongue in the head up positions may compromise the airway. What is the cause of edema in these areas in a head up position?
Edema is due to obstruction of venous and lymphatic system cause by prolonged marked neck flexion
What precautions should be taken to minimize the occurrence of face, neck, and tongue edema in the head up positions?
Avoid placing the patients chin against the chest and use and oral airway to protect the endotracheal tube
What nerve injury may occur from a sternal notch retractor?
Brachial Plexus (pinching): most often manifest as sensory deficit in the distribution of the ulnar nerve
Describe the method and rationale for denitrogenation (pre-oxygenation) of the airway
tight mask seal, 100% O2 at high flow rate (10-12 L/min),
How is an oropharyngeal airway sized? What problems may be seen with their usage?
From the corner of the mouth to the angle of the jaw or earlobe. Poorly sized can cause worse obstruction, lingual nerve palsy, and damage to teeth