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.