General Topics 2 Flashcards
A 20-year-old 80 kg male is scheduled to undergo laparoscopic cholecystectomy. You have an unanticipated difficult airway with a grade 3 view during laryngoscopy and difficulty with mask ventilation. You insert a laryngeal mask airway (LMA), size #4 Unique, and are able to ventilate. You are contemplating your next step and decide to intubate through the LMA. What is the LARGEST size endotracheal tube that can fit through this #4 Unique LMA? (I.D. = internal diameter)
A Unique LMA #4 will fit up to a 6.0 mm I.D. endotracheal tube.
I gel - 4 size 7.0
Ambu aura - 4 size 7.5
Which of the following is the MOST correct with regard to proper use and administration of propofol for induction or maintenance of general anesthesia?
Due to reports of bacterial contamination and patient reactions, strict aseptic technique should be used when handling propofol, it should be used within 12 hours of opening the vial, all vials should be used for only 1 patient, and it should not be given through the same line as blood or plasma products.
Which of the following is NOT a predictor of a difficult intubation?
The 11 non-reassuring findings are:
1) Relatively long incisors
2) Prominent “overbite”
3) Patient cannot bring mandibular incisors anterior to maxillary incisors
4) Less than 3 cm interincisor distance
5) Uvula is not visible when tongue is protruded with patient in sitting position
6) Highly arched or very narrow palate
7) Mandibular space that is stiff, indurated or occupied by a mass
8) Less than three ordinary finger breadth thyromental distance
9) Short neck length
10) Thick neck circumference
11) Decreased extension or flexion of the neck
Which of the following is NOT a suggested guideline by the Institute of Medicine regarding conflict of interest in research, education, and clinical practice?
Personal relationships, paid expert testimonial, travel grants, and relationships with outside organizations are not part of the standard conflict of interest disclosure requirements suggested by the Institute of Medicine. The ASA definition of conflict of interest is somewhat broader than that of the Institute of Medicine and calls for all speakers at ASA meetings to disclose “arrangements which could be viewed as affecting the objectivity of the lecturer’s presentation.
What would be the MOST efficient way to decrease operating costs in the operating room?
Labor costs are mostly related to the efficient utilization of staff and scheduling of cases. To change these costs, it is best to match staffing to operating room scheduling and to decrease the number of per diem anesthesiologists.
A 45-year-old female is undergoing laparoscopic cholecystectomy. The surgeon inadvertently injures a vessel, requiring administration of 4 units of PRBCs and 2 units of FFP. Anesthesia is maintained at 1 MAC. After 15 minutes, the surgeon requests steep Trendelenburg position to better visualize the bleed. Shortly after, the SpO2 alarms for a value of 88% (alarm cutoff of 90%). Blood pressure has increased slightly to 134/85 mmHg. You note that the peak airway pressures are up to 40 cmH2O from 22 cmH2O. Of the following options, which is the MOST APPROPRIATE?
Endobronchial intubation is a common cause of hypoxemia in the operating room with symptoms of asymmetric breath sounds and chest expansion, increased peak airway pressures, and decreasing SpO2. It most commonly occurs at intubation or with positioning changes.
A 26-year-old female has significant postoperative nausea and vomiting in the PACU after laparoscopic cholecystectomy. Her symptoms improve after receiving ondansetron, metoclopramide, and prochlorperazine. Shortly thereafter, she develops facial and neck muscle spasms. Which of the following is the BEST treatment?
Medications that disturb the dopaminergic-cholinergic balance in the basal ganglia (e.g., neuroleptics and dopamine receptor antagonists) can cause acute dystonic reactions. Treatment usually includes anticholinergic medications or benzodiazepines.
Which of the following is a component of the Model for End-stage Liver Disease (MELD) score?
The Model for End-stage Liver Disease (MELD) score replaced the modified Child-Pugh score for prioritization of patients for liver transplantation. The MELD score includes a patient’s serum creatinine, bilirubin, international normalized ratio, and sodium.
TrueLearn Insight : Mnemonics to help differentiate MELD from modified Child-Pugh:
MELD: “I Crush Several Beers Daily” for international normalized ratio, creatinine, sodium, bilirubin, dialysis
Childs-Pugh: “Pour Another Beer At Eleven” for prothrombin time, ascites, bilirubin, albumin, encephalopathy
Which of the following tests is the MOST sensitive for identifying malignant hyperthermia?
The halothane-caffeine contracture test has highest sensitivity and is considered the current gold standard for diagnosis of malignant hyperthermia. While genetic testing for mutations of the ryanodine receptor has become increasingly common, not all genetic defects representing malignant hyperthermia have been identified.
Which of the following statements regarding perioperative ulnar neuropathy is TRUE?
Postoperative ulnar nerve injury is the most common form of perioperative peripheral neuropathy. It occurs more commonly in males and very thin or obese patients. Ulnar neuropathy is typically transient but can persist and cause morbidity and disability. Nerve conduction studies are beneficial in evaluating both motor and sensory deficits. Electromyography can help determine the timing of the nerve injury.
Which of the following is TRUE regarding negative pressure pulmonary edema?
Negative pressure pulmonary edema has an incidence of 0.05-0.1% in all general anesthetics. Risk increases to 4% if airway obstruction occurs in a spontaneously breathing patient. Other risks include young age, male gender, physical fitness, and HEENT surgery.
Left ventricular afterload is increased when obstruction occurs, with the development of a significantly negative intrathoracic pressure. Additionally, the negative intrathoracic pressure causes an increase in preload
According to the Society for Ambulatory Anesthesia consensus guidelines, which of the following is LEAST likely to reduce the risk of a patient developing postoperative nausea and vomiting?
A number of different strategies exist that can decrease a patient’s baseline risk for PONV. The six identified by the Society for Ambulatory Anesthesia include:
1) Avoid general anesthesia by utilizing regional anesthesia
2) Use propofol for induction and maintenance of anesthesia
3) Avoid nitrous oxide
4) Avoid volatile anesthetics
5) Minimize intra- and post-operative opioids
6) Adequately hydrate the patient
Which of the following scenarios carries the LOWEST risk for the development of postoperative hepatic dysfunction?
The type of surgery is most likely the biggest risk factor in determining whether postoperative hepatic dysfunction will occur. Following that is the presence of acute or chronic hepatitis and cirrhosis. Elevation in AST < 2 times normal, especially if asymptomatic, are unlikely to result in the development of postoperative hepatic dysfunction.
Which of the figures is MOST consistent with a patient being mechanically ventilated using synchronous intermittent mandatory ventilation with pressure support?
Synchronized intermittent mandatory ventilation is often used in the operating room to transition a patient from controlled to spontaneous breathing. Tidal volume and a minimum respiratory rate for the mandatory breaths are set, yielding the minimum minute ventilation. It is time or pressure initiated, volume limited, and cycled by time or volume. The SIMV mode attempts to synchronize the mandatory breaths with a patient’s spontaneous inspiratory effort. Accordingly, the interval between mandatory breaths may be irregular.
A 70-year-old nonsmoking 70 kg male is admitted to the ICU after an exploratory laparotomy for bowel perforation secondary to bowel obstruction. He is POD 1 and the bowel is left in discontinuity. He has a nasogastric tube in place that has been draining approximately one liter of fluid daily. He has received 3 liters of normal saline for resuscitation, is on no vasopressors, and blood pressure is 110/60 mm Hg. He is currently intubated and you are attempting to wean him from the ventilator but are having trouble while on pressure support mode. He has a fentanyl infusion going at 25 mcg/hour, pupils are not pinpoint, and the patient does not appear sedated or uncomfortable. Which of the following is MOST likely cause of his failed ventilator weaning?
Metabolic alkalosis results from excessive hydrogen ion loss or excessive bicarbonate production (or impaired loss) resulting in compensatory hypoventilation to raise PaCO2 in attempts to bring the pH back towards normal. A general rule of thumb is that the PaCO2 will increase by 0.5 mm Hg for every 1 mEq/L increase in bicarbonate.
A 46-year-old female suffered a 40% total body surface area burn one week ago, primarily consisting of 2nd degree burns. Her renal function and electrolytes are normal other than hypoalbuminemia. Relative to a healthy patient, lower doses of which of the following medications should be administered?
Severe burns lead to hypoalbuminemia which increases the free fraction of many anesthetic drugs including benzodiazepines and opioids. Lower doses of benzodiazepines should be considered, while higher doses of opioids are usually required due to the rapid development of tolerance. Insulin resistance is seen due to increased catecholamine and corticosteroid levels. Proliferation of extrajunctional acetylcholine receptors leads to exaggerated hyperkalemia with succinylcholine use and resistance to nondepolarizing neuromuscular blockers.
You are seeing a 70-year-old male in the preoperative clinic for total hip arthroplasty. The patient has a history of aortic stenosis (AS), hypertension, and diabetes. His last echocardiogram was six months ago which revealed stable severe AS. The patient states he is doing well, his heart rate is 60 bpm, and blood pressure is 120/80. He does not have any new symptoms but has new crackles on pulmonary exam. Which of the following should be performed prior to his surgery?
Patients with aortic valve disease have potentially increased risk of perioperative morbidity and mortality. An echocardiogram should be obtained in patients with moderate, severe, or critical stenosis or regurgitation if it has not been performed in the past year or there is a change in their symptoms or physical exam.
Aortic stenosis:
- Severe aortic stenosis is defined as a valve area less than 0.8 cm2 and a transvalvular pressure gradient higher than 50 mmHg.
- The “triad” of symptoms include: angina, syncope, and shortness of breath (dyspnea). The degree of symptoms does not correlate with the degree of stenosis.
- HR: normal sinus rhythm should be maintained since loss of the left atrial contraction will result in a dramatic decrease in stroke volume and blood pressure. A normal to slower heart rate is beneficial to allow as much time for ventricular filling as possible. Furthermore, elevations in heart rate can lead to ischemia due to decreased diastolic time.
- Contractility: want to maintain, avoid depression of contractility which can lower stroke volume.
- Preload: want to have adequate volume.
- Afterload: must be maintained distal to the stenotic lesion to ensure coronary perfusion. A decrease in blood pressure can lead to myocardial ischemia which will further worsen contractility.
- Cardiac resuscitation is not typically effective in patients with AS; code situations must be avoided as it is generally not possible to created adequate stroke volume with chest compression in these patients.
Aortic regurgitation:
- The magnitude of regurgitant volume depends on the diastolic time and the pressure gradient across the aortic valve (dependent on systemic vascular resistance).
- HR: must be kept above 80 bpm to prevent increases in the time for regurgitation. Decreased heart rates, which will increase diastolic time, will allow more regurgitation.
- Contractility: want to maintain.
- Preload: need adequate volume loading to ensure enough volume can move forward. Want to avoid overloading patient because this will increase regurgitant volume.
- Afterload: want to lower systemic vascular resistance which will attempt to prevent more regurgitation.
Which of the following descriptions most correctly correlates with an ASA physical status 4 classification?
The ASA physical status classification is not intended for use as a measure to predict operative risk but to assess the degree of patients’ comorbidities and overall physical state prior to surgery. ASA physical status 4 indicates patients with severe systemic disease that is a constant threat to life such as a hypertensive patient with chest pain at rest (unstable angina).
TrueLearn Insight : The updated ASA Physical Status no longer includes “not expected to survive 24 hours without an operation”; the 24 hours part was removed.
Which of the following statements is INCORRECT regarding the use of sevoflurane for mask induction of anesthesia in adult patients?
Inhalational anesthetic induction in adult patients typically preserves spontaneous ventilation and does not cause salivation. Stage II (excitation) is typically not seen. Pretreatment with benzodiazepines helps to improve the technique while pretreatment with opioids worsens the technique by potentially causing apnea.
A 33-year-old male with cerebral palsy is scheduled for elective contracture release surgery. His mother says that over the past several weeks, the patient has become increasingly tired and his appetite has been unusually poor. Medications include diazepam 5 mg as needed for anxiety and muscle spasticity and dantrolene 50 mg four times daily for spasticity. Which of the following preoperative tests is MOST likely indicated prior to surgery?
Chronic use of dantrolene is associated with hepatotoxicity and, in severe cases, may lead to liver failure and death if unrecognized. Patients on chronic dantrolene therapy should routinely have LFTs monitored.
