General Topics Flashcards
A 4-year-old male with a history of upper respiratory tract infection 2 weeks prior is undergoing emergent exploratory laparotomy for bowel obstruction. The case goes well and you decide to extubate the patient. Upon extubation you note sternal retractions, faint stridor, and paroxysmal breathing. SpO2 is 95%, HR is 100 beats per minute, and blood pressure is 100/60 mm Hg. No ETCO2 tracing is seen. Which of the following is the LEAST appropriate in this situation?
Laryngospasm management involves: 100% oxygen with positive pressure < 20 cm H2O, Larson maneuver, optional IV anesthetic, and last resort IV succinylcholine.
Assist-control ventilation
Pressure vs. time tracings of AC ventilation can be recognized by the lack of spontaneous breathing independent of the ventilator. All breaths involve full ventilator support and are synchronized with patient effort, when present.
Which of the following is NOT true regarding intravenous fentanyl abuse by anesthesiologists?
Fentanyl is the most commonly abused opioid and others often detect the abuse within 6-12 months. Only 34% of anesthesiology residents who abuse fentanyl have been shown to successfully re-enter anesthesiology training programs, and 16% of parenteral opioid abusers show death as the first relapse symptom.
A patient is undergoing a laparoscopic cholecystectomy utilizing carbon dioxide insufflation. Which of the following is MOST true regarding the use of nitrous oxide as part of a balanced anesthetic?
Nitrous oxide can affect surgical visualization and the patient’s risk for PONV, particularly with prolonged surgery. No clinically significant effect of nitrous oxide on the risk of PONV exists under an hour of exposure.
Which of the following will MOST LIKELY increase the risk for intraoperative awareness?
Intraoperative awareness is a feared complication of anesthesia such that the patient has consciousness and memory of surgical events. Patient-related factors increasing the risk of intraoperative awareness include difficult intubation, obesity, chronic alcohol, benzodiazepine, and opioid use. Surgeries with a higher risk of intraoperative awareness include cesarean section, cardiac surgery with cardiopulmonary bypass, and trauma surgeries.
Which of the following patients requires antibiotic prophylaxis for a dental procedure involving gingival tissue manipulation?
The list of patients who should receive prophylaxis is below:
- Patients with a prosthetic cardiac valve
- Patients who have previously had IE
- Patients with unrepaired cyanotic congenital heart disease (including palliative shunts/conduits)
- Patients with congenital heart defects which were repaired with prosthetic material within 6 months of the procedure
- Patients with repaired congenital heart disease with residual defects at the site, or adjacent to the site, of a prosthetic patch or device
- Cardiac transplantation recipients who develop cardiac valvulopathy (substantial leaflet pathology and regurgitation)
Of note, prophylaxis only applies to certain surgical procedures:
- Dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa
- Invasive respiratory tract procedures that involve incision or biopsy of the respiratory mucosa (e.g. tonsillectomy, adenoidectomy)
- Infected skin, skin structure, or musculoskeletal tissue
Which of the following statements regarding P50 of the oxyhemoglobin dissociation curve is TRUE?
oxygen affinity is highest (P50 is lowest) as a newborn due to hemoglobin F. Over the next 2-3 months, levels of hemoglobin F decrease and 2,3-DPG increase, resulting in rightward shift of the oxyhemoglobin curve. Oxygen affinity reaches its lowest (P50 is highest) around 12 months of age. P50 will reach normal adult level after about age 10.
P50 is lowest in newborns (18 mm Hg) and is highest in children over 12 months of age (30 mm Hg). After 10 years of age, P50 decreases to adult level (27 mm Hg).
TrueLearn Insight : P50 increases due to: acidosis, hypercarbia, hyperthermia, increased 2,3-DPG. Shift “RIGHT”: Rise In 2,3-DPG, H+, and Temp. P50 decreases due to: alkalosis, hypocarbia, hypothermia, decreased 2,3-DPG.
modified Cormack-Lehane system
Grade I Visualization of the entire laryngeal aperture
Grade II Posterior third of glottis visible
Grade IIa Arytenoids and posterior cords visible
Grade IIb Only epiglottic edge and arytenoids visible
Grade III No cords visible, only epiglottis visible
Grade IIIa Only epiglottic edge visible (epiglottis raised)
Grade IIIb Downfolded or floppy epiglottis visible
Grade IV No view of any airway structure (including epiglottis)
Which of the following configurations of the pulse oximeter results in the highest risk of injury from burn when the patient is having magnetic resonance imaging (MRI) of his or her brain?
The risk of thermal injury to patients during MRI can be decreased by using proper precautions: ensuring compatible equipment, checking the equipment to ensure proper integrity before use, positioning cables and wires to exit down the center of the MRI system (not along the side of the system or close to the coils) and placing pulse oximeters on the furthest point possible from the body part being scanned. Coiling cables significantly increases the risk of burns.
Accidental endobronchial intubation would MOST significantly slow the relative rate of induction of which of the following volatile anesthetics?
Pulmonary venous admixture from a non-ventilated lung will reduce the Pa of an inhalational anesthetic, thereby increasing the time it will take for the agent to reach equilibrium. This effect is augmented for less soluble volatile agents because their low blood:gas coefficients lead to a relatively greater dilutional effect from the non-ventilated lung.
Which of the following helps decrease the amount of heat lost due to redistribution from the core to periphery during the first thirty minutes of general anesthesia?
Forced air warming devices are the most effective way to decrease temperature loss during general anesthesia. If possible, even a small area of forced air warming applied to the patient in the preoperative period can help decrease the core to peripheral heat loss that occurs in the first hour of general anesthesia.
TrueLearn Insight : Heat transfer from the patient to the environment in the operative period occurs through four mechanisms (radiation and convection are the two biggest contributors):
Radiation: Patient will radiate heat to surrounding environment. Heat is transferred from the core to the subcutaneous vessels, then lost to the environment via infrared rays. This is likely the major type of loss.
Convection: The thin layer of air adjacent to the skin acts as an insulator and when air currents disrupt this layer the insulating properties are lost. Since the room air in the operating room typically is exchanged every 15 minutes, this can result in serious loss of the insulator.
Conduction: Transmission of body heat through conducting medium without perceptible motion of the medium. In general, this is small because the patient is only in contact with the foam mattress of the operating room table (which is often insulated).
Evaporation: When liquid is changed into a vapor, a lowering of the kinetic energy results in a decreased temperature. In the operating room, this typically occurs when sterile preparation solutions are applied or through surgical wound evaporation.
A patient is undergoing carpal tunnel release surgery. The anesthesiologist plans to use intravenous regional anesthesia (IVRA) for pain control during the procedure. What is the primary mechanism of IVRA?
The mechanism of IVRA is blockade of nerves by local anesthetic through the vascular bed, reaching both peripheral nerves and nerve trunks (vasa nervorum), as well as nerve endings (valveless venules). Additional contributing components may include diffusion of local anesthetic into the surrounding tissues, ischemia/compression of the peripheral nerves at the level of the inflated cuff, tissue asphyxia, tissue hypothermia, and tissue acidosis.
Which of the following statements regarding carbon dioxide absorbents is TRUE?
Carbon dioxide absorbents containing barium hydroxide produce the most compound A and have the highest risk for fire production during sevoflurane administration. Soda lime, due to higher water content, has a reduced incidence of compound A and fire production. Calcium hydroxide absorbents, due to lower reactivity, have the lowest incidence of compound A and fire production. Desiccated absorbents absorb less CO2, produce more heat and carbon monoxide, and have an increased risk of compound A and fire production.
Compared with adult patients who fast from clear liquids for > 4 hours, those who fast between 2-4 hours have:
Ingestion of water 2 hours prior to a procedure results in smaller gastric volumes and higher gastric pH when compared with those who ingested > 4 hours prior.
Radiation exposure changes by which of the following when the distance from a source of ionizing radiation is doubled?
I ∝ 1 / r^2 Where: I = intensity, S = source strength, r = radius (distance from source) Radiation intensity (exposure) with respect to distance decreases according to the inverse square law: I ∝ 1 / r^2. Accordingly, doubling the distance from a radiation source decreases exposure by a factor of 4.
Which of the following BEST describes how to administer neostigmine for treatment of succinylcholine apnea in a patient with atypical plasma cholinesterase?
Succinylcholine apnea in a patient with abnormal pseudocholinesterase can potentially be reversed with low dose neostigmine (< 0.03 mg/kg) after a phase II block occurs. However, the safest course of action is generally continuation of mechanical ventilation until adequate muscle tone returns. Further, giving neostigmine in this scenario could potentially prolong the blockade.
A femoral and sciatic nerve block are to be placed in a 44-year-old woman in a preoperative block area prior to ankle surgery. If no sedation will be given during block placement, which of the following is required to be monitored during the blocks?
Continuous ECG should be used for all anesthetics regardless of whether sedation is used or not.
You are working in a large academic center with 30 colleagues. You have noted that one of your colleagues is showing signs of substance abuse. What is the best way to approach your colleague about getting help?
If you suspect a colleague of having a substance abuse problem, you should consult your state physicians health program before intervention or confrontation.
Which of the following physical exam findings predicts difficulty with mask ventilation in an obese patient?
Neck circumference > 60cm is associated with difficult mask ventilation.
TrueLearn Insight : It is important to stress that the predictors for difficult mask ventilation and difficult intubation are not exactly the same. The risk factors for difficult intubation are decreased mouth opening, reduced thyromental distance, Mallampati class III or IV, decreased neck mobility, inability to prognath, obesity, and a history of difficult intubation.
A 36 year-old patient with a history of severe asthma and GERD is undergoing ORIF of the distal humerus. He has sinus tachycardia at 138 bpm and a blood pressure of 115/66 mm Hg. Which of the following would NOT be an appropriate treatment option?
In a patient with asthma, nonspecific (beta1 and beta2) beta-blockade can exacerbate bronchospasm thus it should only be given after all other causes of sinus tachycardia have been ruled out.
Mean alveolar concentration requirements for anesthesia are the LOWEST in which of the following patients?
MAC rises at one month of age, peaks at approximately 6 months of age, and regress back to normal at 1 year of age. Excluding patients less than one year of age and pubertal patients, the minimum alveolar concentration (MAC) of inhaled anesthetics decreases with age.
A 67-year-old female presents to the anesthesia pre-evaluation clinic prior to undergoing total hip arthroplasty. Her past medical history includes hypertension, hyperlipidemia, atrial fibrillation (on apixaban), asthma, GERD, and type 2 diabetes (on metformin). Which of the following tests should be ordered prior to surgery?
Traditional coagulation studies (PT/INR, PTT, thrombin time) in a patient taking apixaban and scheduled for total hip arthroplasty are not required pre-operatively.
The following arterial blood gas measurements are obtained after uneventful topicalized flexible bronchoscopic intubation with confirmed endotracheal tube placement:
pH: 7.23 pCO2: 39 mm Hg PaO2: 216 mm Hg HCO3: 15 mEq/L BE: -11 SaO2: 86%
Which of the following is the first BEST treatment option?
Prilocaine and benzocaine are local anesthetics known to induce methemoglobinemia. These agents are commonly used for upper airway topicalization prior to awake flexible bronchoscopy and intubation. Standard pulse oximetry SpO2 readings of 85-88% are commonly noted in the setting of methemoglobinemia. Methylene blue (1-2 mg/kg) is the primary pharmacologic treatment of methemoglobinemia.
TrueLearn Insight : Methylene blue is a monoamine oxidase inhibitor. Doses > 5mg/kg in the setting of selective serotonin reuptake inhibitor use may precipitate serotonin crisis. For this reason, indigo carmine may be preferred for use in detecting ureteral injury.
Which of the following is an adaptation to high altitude?
Short-term adaptations (first several hours) to hypoxemia at altitude include increased minute ventilation and cardiac output. Intermediate adaptations (hours to days) include a rightward then leftward shift of the oxygen-hemoglobin dissociation curve, CSF bicarbonate loss, and enhanced renal bicarbonate excretion. A long-term adaptation (weeks) is increased hemoglobin concentration from increased erythropoietin secretion. These adaptations ultimately result in a normal blood pH, decreased PaCO2, decreased blood bicarbonate concentration, and increased oxygen delivery to tissues despite a decreased PaO2.
Which of the following statement is TRUE regarding respiratory physiology in the morbidly obese?
Respiratory changes associated with obesity include increased work of breathing, oxygen consumption, and DLCO. Expiratory reserve volume, functional residual capacity, and tidal volume are decreased. Mechanical ventilation decreases oxygen consumption dedicated to respiratory work in obese by 16%.
Which of the following characteristics are shared by both conscious sedation, administered by a non-anesthesia provider, and monitored anesthesia care?
Both moderate sedation and MAC are recognized as physician-delivered services in the CPT coding system. Monitored anesthesia care requires post-procedural transfer to a post-anesthesia recovery area as well as a provider trained in the ability to convert to GA and intervene during airway compromise.
According to the American Society of Anesthesiologists, which of the following differentiates the requirements between care administered during monitored anesthesia care (MAC) and that of sedation in a non-anesthesia setting?
The distinction between sedation provided outside of an anesthesia setting and that provided under MAC can be confusing as there is overlap in responsibilities. The important distinction between the two is that, in MAC, the provider must be able to anticipate adverse events and intervene when necessary to secure the patient’s airway or convert to general anesthesia. Additionally, the anesthesiologist performing MAC must be separate from the person performing the procedure for which the sedation is required.
TrueLearn Insight : One of the most important tasks anesthesiologists do is monitor the depth of sedation given to a patient and anticipate the airway and cardiovascular derangements that can occur with deeper levels of sedation. The different levels of sedation, according to the American Society of Anesthesiologists, are as follows:
Minimal Sedation: normal response to verbal stimulation, the airway remains unaffected, spontaneous ventilation maintained, and cardiovascular function unaffected.
Moderate Sedation: purposeful response to verbal or tactile stimulation, no intervention required to maintain a patent airway, adequate spontaneous ventilation, and cardiovascular function usually maintained.
Deep Sedation: purposeful response following repeated or painful stimulation, airway intervention may be required, spontaneous ventilation may be inadequate, and cardiovascular function usually maintained.
General Anesthesia: unarousable even with painful stimulation, intervention on the airway often required, spontaneous ventilation is inadequate, and cardiovascular function may be impaired.
Placing foam padding under a patient’s sacrum during prolonged surgical cases in the supine position will MOST likely prevent which of the following complications?
Bony prominences, such as the elbows, heels, and the sacrum are at risk for skin ischemia and necrosis during anesthesia if not properly padded due to the compression of capillaries and small blood vessels. Padding may be used to prevent skin injury, particularly during prolonged surgical procedures, which may also decrease the risk of perioperative peripheral neuropathies.
TrueLearn Insight : Postoperative visual loss may occur due to intraoperative ocular compression while the patient is in the prone position. Circumferential padding of the forehead and zygoma helps sustain the head while avoiding direct ocular compression.
Which of the following is a risk factor for the development of postoperative cognitive dysfunction in a patient having surgery?
Risk factors for POCD are advancing age, lower educational level, and a history of previous cerebral vascular accident with no residual impairment.
Following an uneventful two-level lumbar laminectomy, a 56-year-old male complains of ocular pain in the PACU. Which of the following is the LEAST likely diagnosis?
Complications of nonocular surgery that can lead to postoperative ocular pain include corneal abrasions (most common), foreign body introduction, chemical injury, and rarely, acute glaucoma. Ischemic optic neuropathy leads to painless vision loss.
Which of the following is LEAST likely to be associated with a latex allergy?
Healthcare workers, children with spina bifida and urogenital syndromes, and those with allergies to banana, avocado, kiwi, pineapple, mango, and other tropical fruits have an increased risk for development of a latex allergy. Frequent cosmetic use may be related to antibodies against aminosteroid neuromuscular blocking drugs (pancuronium, pipercurium, rocuronium, and vecuronium), but there is no increased association with a latex allergy.
Which of the following properties does preparation of the nasal mucosa with a vasoconstrictor attempt to provide during nasal fiberoptic intubation?
Although nasotracheal intubation is generally considered more difficult, it is better tolerated than oral intubation. General indications for nasotracheal intubation include surgical procedures that require the oropharynx to be free, and in some specific surgeries where securing the endotracheal tube would be difficult. Contraindications include severe coagulopathy, high-dose systemic anticoagulation, known nasal or paranasal pathologies, infection of the paranasal sinuses, basilar skull fracture, and traumatic brain injury with liquor leakage (cerebrospinal fluid [CSF] leakage). Complications of nasal intubation include bleeding, necrosis of the tip of the nose, and complications induced by the impaired drainage of paranasal sinus secretions.
TrueLearn Insight : Common airway blocks are outlined below.
Glossopharyngeal nerve:
Displace tongue medially, forming the glossogingival groove (the formed gutter by displacing the tongue) –> use a 25-gauge spinal needle inserted at the base of the tonsillar pillar (just lateral to the base of the tongue) to a depth of 0.5 cm –> aspirate to ensure venous/arterial puncture or tracheal infiltration has not occurred –> inject 2 mL of 2% lidocaine –> repeat on other side.
Superior laryngeal nerve:
Three landmarks may be used: (1) superior cornu of the hyoid and (2) superior cornu of the thyroid cartilage –> 25-gauge spinal needle is walked off the cornu anteriorly toward the thyrohyoid ligament until resistance is felt as the needle goes through the ligament –> after negative aspiration –> inject 2 mL of 2% lidocaine; (3) 2 cm lateral to the superior notch of the thyroid –> insert needle and direct in a posterior/cephalad direction to 1.5 cm –> 2 mL of 2% lidocaine injected; this method is useful in obese patients, where palpation of the hyoid or superior cornu of the thyroid may be difficult.
Recurrent laryngeal nerve = translaryngeal (or transtracheal):
Makes examination after intubation more tolerated and helps with comfort while placing the endotracheal tube: find the cricothyroid membrane –> use a 20 to 22-gauge needle attached to 5 mL syringe (use of an IV catheter will allow the needle to be removed and the catheter to remain) –> direct posteriorly and slightly caudally until air is aspirated –> inject 4 mL of 2% or 4% lidocaine. If the needle is kept in place, there may be damage to the posterior tracheal wall or structures posterior to the trachea with patient coughing.
You suspect a colleague of diverting and abusing fentanyl. Which of the following is TRUE?
Substance abuse disorders occur in anesthesia providers and can have deadly results if not treated. It is important to report a suspected colleague. Most states have physician health programs that can be consulted for intervention help along with getting the affected individual into an appropriate treatment program.
Which of the following statements concerning anesthetic agents in the setting of renal dysfunction is TRUE?
The active metabolite in meperidine, normeperidine, causes seizure activity. Morphine’s primary active metabolite, M6G, has a 100-fold greater potency, but exhibits an equal or decreased affinity for μ-receptors compared to morphine. Accumulation of M6G can result in respiratory depression. Morphine’s inactive metabolite, M3G, may cause myoclonus and allodynia. As morphine and meperidine metabolites are typically excreted via the kidneys, their side effects are prolonged in the setting of renal failure. Barbiturates have decreased protein binding in renal failure which leads to higher concentrations of free active molecules.
TrueLearn Insight : The meperidine molecule resembles atropine. Increased heart rate may occur as a side effect of meperidine administration.
Which of the following is the expected oxygen saturation reading using a standard pulse oximeter in the setting of methemoglobinemia in a patient with a normal partial pressure of oxygen (PaO2)?
Conventional pulse oximetry can neither detect MetHgb nor accurately measure SpO2 in the presence of elevated MetHgb levels, because MetHgb absorbs light at both 660 nm and 930 nm equally. Standard 2-wavelength pulse oximeters generally give measurements approaching 85% in the presence of high methemoglobin levels. In the setting of suspected methemoglobinemia, multi-wavelength co-oximetry should be used.
A 43-year-old male with compensated liver cirrhosis is scheduled for minor surgery under general anesthesia. Lab results reveal a platelet count of 62 and an international normalized ratio of 2.1.
Which of the following is MOST likely to be increased in this patient?
Liver disease reduces factors II, VII, IX, and X, as well as V, XI, and thrombin. Protein C is also reduced. Factor VIII and vWF are increased in patients with liver disease, as they are produced extra-hepatically.
A 43-year-old man with compensated liver cirrhosis is scheduled for minor surgery under general anesthesia. Laboratory results reveal a platelet count of 62 and an international normalized ratio of 2.1. Which of the following describes the MOST appropriate management for this patient?
Coagulation management in liver disease patients:
Maintain platelet count at 50-60; in high-risk surgery, maintain count at >100.
Keep fibrinogen >100.
Transfuse to maintain Hgb >7.
Do not give fresh frozen plasma (FFP) prophylactically or chase INR levels:
Increased INR in these patients does not necessarily reflect the risk of bleeding
If FFP is to be given, the dose is 20-40 mL/kg
