Anesthesia 2nd year Flashcards
To determine the etiology of hypoxemia, calculate the?
A-a gradient to narrow thedifferential diagnosis
When other causes have been ruled out, persistent and refractory hypotension in trauma or other critically ill patients may be caused by (2)
hypocalcemia
hypomagnesemia
Speed of onset of volatile anesthetics is increased by (4)
Increasing the
- Concentration
- Fresh gas flow
- Alveolar ventilation
- Using non-lipid soluble agents
Termination of effect of intravenous anesthetics is by ________________ , not biotransformation and breakdown.
Redistribution
- Lipid solubility, pKa, and protein binding of the local anesthetics determine their _______, _________, and _____________, respectively
- Potency
- Onset
- Duration
When compressed, some gases condense into a liquid such as (2) and some do not such as (2)
- N2O and CO2
2. O2 and N2
Most commonly used anesthesia circuit?
What are its components (6)?
- Semiclosed circuit using a circle system
- inspiratory limb
- expiratory limb
- unidirectional valves
- CO2 absorber
- Gas reservoir bag
- Pop-off valve on the expiratory limb
Every patient ventilated with an ascending bellows anesthesia ventilator receives approximately ___ cm H2O of positive end-expiratory pressure (PEEP) because of the weight of the bellows.
2.5 to 3 cm H2O
The first step in the care of the hypoxic patient fighting the ventilator is to?
Ventilate the patient manually with 100% oxygen
Risk factors for auto-PEEP include (4)
- High minute ventilation
- Small endotracheal tube
- Chronic obstructive pulmonary disease
- Asthma
Below a hemoglobin saturation of ____, a small decrease in saturation corresponds to a large drop in PaO2.
90%
Except for visualization with bronchoscopy, _____ is the best method of verifying
endotracheal tube location.
CO2 detection
If a patient’s ______ is excellent, even in the presence of ischemic heart disease, the chances are good that the patient will be able to tolerate the stresses of surgery.
Exercise capacity
The necessary criteria for acute lung injury/acute respiratory distress syndrome (ALI/ARDS) include: (5)
(1) Acute onset
(2) PaO2/FiO2 ratio of 300 for ALI
(3) PaO2/FiO2 ratio of 200 for ARDS
(4) Chest radiograph with diffuse infiltrates
(5) Pulmonary capillary wedge pressure of 18 mm Hg
Mechanical ventilation settings for patients with ARDS or ALI include tidal volume of at _____ of ideal body weight while limiting plateau pressures to ______ cm H2O. FiO2 should be adjusted to maintain
oxygen saturations between __________.
6 to 8 ml/kg
<30 cm H20
88% and 92%
Measures to acutely decrease intracranial pressure (ICP) include (4)
- elevation of the head of the bed
- hyperventilation (PaCO2 25 to 30 mm Hg)
- diuresis (mannitol and/or furosemide)
- minimized intravenous fluid
Malignant hyperthermia (MH) is an inherited disorder that presents in the perioperative period after exposure to inhalational agents and/or succinylcholine. The disease may be fatal if the diagnosis is delayed and dantrolene is not administered. The sine qua non of MH is an unexplained rise in \_\_\_\_\_\_\_\_\_\_, with a simultaneous increase in \_\_\_\_\_\_\_\_\_\_\_, in the setting of an unexplained, \_\_\_\_\_\_\_\_\_\_\_.
Rise in end-tidal carbon dioxide
Increase in minute ventilation
Unexplained tachycardia
In patients with ___________ spinal anesthesia should be used with caution and only in situations in which the benefits of spinal anesthesia over general anesthesia are clear.
Multiple sclerosis
The inability to touch the palmar aspects of the index fingers when palms touch (the ____sign) can indicate a difficult oral intubation in patients with diabetes.
Prayer sign
The initial goal of burn resuscitation is to correct ________.
Hypovolemia
Abrupt oxygen desaturation while transporting an intubated pediatric patient is probably the result of ___________?
Main stem intubation
Infants may be difficult to intubate because they have a more anterior larynx, relatively large tongues, and a floppy epiglottis.
The narrowest part of the larynx is below the vocal
cords at the _______
Cricoid cartilage
Best first step in treating a pulmonary hypertensive event?
Hyperventilation with 100% oxygen
If a child with tetralogy of Fallot has a hypercyanotic spell during induction of anesthesia, _____________, can reverse the right-to-left shunt
while pharmacologic treatments are being prepared.
Gentle external compression of the abdominal aorta
Read
In preeclampsia hypertension should be treated, but blood pressure should NOT be normalized.
Spinal anesthesia may be preferable to general anesthesia when the preeclamptic patient does not have an existing epidural catheter or there is insufficient time because of nonreassuring fetal heart rate tracing.
Read
If a patient is pacemaker dependent, the interference by electrocautery may be interpreted by the device as intrinsic cardiac activity, leading to profound inhibition of pacing and possible asystole. Devices should be programmed to the asynchronous mode before
surgery.
______ blood is the universal donor for packed red blood cells; for plasma it is ______.
O-negative blood
AB positive
Always reassess optimal positioning of any lung-isolation device after repositioning the patient. A malpositioned tube is suggested by (2)
- acute increases in ventilatory pressures
2. decreases in oxygen saturation
Methods to improve oxygenation during one-lung ventilation include (5)
- increasing FiO2
- adding PEEP to the dependent lung
- adding continuous positive airway pressure to the
nondependent lung - adjusting tidal volumes
- clamping the blood supply to the nonventilated lung
If PaCO2 significantly increases after 30 minutes of pneumoperitoneum, search for another
cause of hypercapnia such as
- capnothorax
- subcutaneous PaCO2
- CO2 embolism
- endobronchial intubation
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ should be considered the drug of choice for the induction of anesthesia for electroconvulsive therapy (ECT).
Methohexital
What kind of pain is usually less responsive to opioids than pain originating from nociceptors?
Neuropathic pain
Indirect-acting sympthomimetics (e.g., ephedrine) depend on ___________release to be effective.
Norepinephrine
Preganglionic sympathetic neurons originate from the _________ of the thoracolumbar spinal cord. These myelinated fibers exit via the _______ and synapse with postganglionic fibers in ____________, ____________, or a ________. Preganglionic neurons may ascend or descend the sympathetic chain before synapsing. Preganglionic neurons stimulate nicotinic cholinergic postganglionic neurons by releasing ______. Postganglionic adrenergic neurons synapse
at targeted end-organs and release __________
Intermediolateral columns
Ventral root of the spinal nerve
Paravertebral sympathetic ganglia, unpaired
prevertebral ganglia, or a terminal ganglion.
Acetylcholine
Norepinephrine
What are the 3 postganglionic receptors of the sympathetic nervous system? (3)
What is the preganglionic receptor of the sympathetic nervous system? (1)
a1, a2, B2
a2
Dopamine receptors are post or preganglionic?
Postganglionic
Preganglionic parasympathetic neurons originate from cranial nerves (4) and sacral segments ____.
III, VII, IX, and X (1973)
2-4
Are hydroxy-substituted phenylethylamines and stimulate adrenergic nerve endings.
Catecholamines
3 naturally occurring catecholamines
Norepinephrine, epinephrine, and dopamine
2 synthetic catecholamines
Dobutamine and isoproterenol
Synthesis of dopamine, norepinephrine, and epinephrine:
The amino acid _______ is actively transported into the adrenergic presynaptic nerve terminal cytoplasm, where it is converted to _____by two enzymatic reactions: (2)
Dopamine is transported into storage vesicles, where it is hydroxylated by ___________ to norepinephrine.
Epinephrine is synthesized in the ________ from norepinephrine through methylation by _______.
Tyrosine
Dopamine
- Hydroxylation of tyrosine by tyrosine hydroxylase to dopamine
- Decarboxylation of dopamine by aromatic L-amino acid decarboxylase.
Dopamine b-hydroxylase
Adrenal medulla
Phenylethanolamine N-methyltransferase
How is norepinephrine metabolized?
Norepinephrine is removed from the synaptic junction by ______ into the presynaptic nerve terminal and __________.
Reuptake
Metabolic breakdown
The enzyme ____________ metabolizes norepinephrine within the neuronal cytoplasm.
Both ______ and _____ metabolize the neurotransmitter at extraneuronal sites.
The important metabolites are (3)
Monoamine oxidase (MAO)
MAO and catecholamine O–methyltransferase (COMT)
- 3-methoxy-4-hydroxymandelic acid
- metanephrine
- Normetanephrine.
The cholinergic neurotransmitter acetylcholine (ACh) is synthesized within presynaptic neuronal
_______by esterification of _____ and ____by the enzyme _______; it is stored in synaptic vesicles until release.
After release, ACh is principally metabolized by acetylcholinesterase, a membrane-bound enzyme located in the synaptic junction. Acetylcholinesterase is also located in other nonneuronal tissues such as _____.
Mitochondria Acetyl coenzyme A Choline Choline acetyltransferase Erythrocytes
Phenylephrine stimulates primarily ____ receptors, resulting in increased systemic vascular resistance and blood pressure.
A1
Ephedrine produces norepinephrine release, stimulating mostly ___ and ___ receptors; the effects resemble those of epinephrine although they are less intense.
A1 and B1
What beta blocker has an a-blocking property?
Labetalol
Closing capacity increases with age and is equal to FRC in the supine individual at approximately ___ years and in the upright individual at approximately ___ years.
44
66
What represents the amount of base (or acid) needed to titrate a serum pH back to normal at 37 C while the PaCO2 is held constant at 40 mm Hg.
BD (or base excess)
Compartment model (%):
Solids?
Fluids?
ICF?
ECF?
ISF (interstitial)?
BV (blood vol)?Solids 43%
Fluids: 57%
ICF: 35%
ISF: 15%
BV: 7%
What hormone body water and tonicity regulated?
Half life?
AHD
20 mins
Hypothalamic osmoreceptors have an osmotic threshold of about ____ mOsm/kg. Above this level ADH release is stimulated.
289
Hypothalamic thirst center neurons regulate conscious desire for water and are activated by an increase in plasma sodium of ___ mEq/L, an increase in plasma osmolality of ___ mOsm/L, and loss of potassium from
thirst center neurons and angiotensin II.
2
4
ADH, or vasopressin, is synthesized in the _____ and ______ nuclei of the hypothalamus.
supraoptic
paraventricular
Where is angiotensinogen produced?
liver
What is the normal range for serum osmolality?
285 and 305 mOsm/L
The most common cause of postoperative hyponatremia is (2)?
SIADH
Water retention
Generally elective surgery should be delayed if serum sodium levels exceed mEq/L?
150
Hyperkalemia >__ mEq/L should be corrected before elective procedures. Usually ____ is the treatment.
6
Dialysis
Changes in stored blood that reduce post-transfusion viability are known as?
Storage lesions
Mild hypothermia (34 to 36 C) increases blood loss by ___ % and increases the relative risk for transfusion by ____ %.
16%
22%
Erythropoietin stimulates erythrocyte production in ___ to ___ days
5 to 7
When a clot is formed, plasminogen is incorporated and then converted to plasmin by tissue plasminogen activator (tPA) and fragments of factor ____.
XII
