Nagelhout Ch. 29, 30

Question 1

Which of the following is a likely potential complication of mediastinoscopy?

Answer 1

Damage to the recurrent laryngeal nerve

Mediastinoscopy can result in a wide range of complications such as tearing of great vessels, pneumothorax, chylothorax, bronchospasm from airway manipulation, air embolism, arrhythmias, recurrent laryngeal nerve palsy, esophageal laceration, and obstruction of blood flow through the innominate artery.

Question 2

Scoliosis caused by cerebral palsy or syringomyelia is categorized as

Answer 2

neuropathic scoliosis

The five categories of scoliosis are based on their etiology. They are: idiopathic, congenital, neuropathic, myopathic, and traumatic. Neuropathic scoliosis is caused by diseases such as polio, cerebral palsy, and syringomyelia. Myopathic scoliosis is caused by conditions such as muscular dystrophy and amyotonia. Idiopathic scoliosis is the most prevalent form.

Question 3

Which of the following would be an appropriate preoperative dose of cimetidine? (select two)

Answer 3

The appropriate preoperative dose of cimetidine is 150 mg- 300 mg oral or IV.

Question 4

Chronic bronchitis differs from emphysema in that patients with bronchitis

Answer 4

have an elevated hematocrit

Patients with chronic bronchitis typically exhibit frequent cough, copious sputum, an elevated hematocrit, increased markings (not hyperinflation) on chest x-ray, elevated PaCO2, normal elastic recoil, and increased airway resistance. In contrast, patients with emphysema have minimal sputum production with a less frequent cough, a normal hematocrit and a PaCO2, decreased elastic recoil, hyperinflation on chest x-ray and a normal to slightly increased airway resistance.

Question 5

Which of the following cartilages of the larynx does not exist as a pair of cartilages?

Answer 5

Epiglottis

The individual cartilages of the larynx are the thyroid, epiglottis, and cricoid. The paired cartilages are the arytenoid, corniculate, and cuneiform.

Question 6

What condition would produce the flow-volume loop shaded in pink? ( shifted Left)

Answer 6

Chronic obstructive pulmonary disease

In obstructive diseases such as COPD, the flow volume loop will appear smaller in size than a normal loop. The peak expiratory flow rate is lower, and the expiratory limb is often sloped downward. This sloping occurs as the smaller airways collapse during expiration.

Question 7

A patient is undergoing general anesthesia for the resection of emphysematous bullae. Which of the following should you avoid?

Answer 7

Nitrous oxide

Nitrous oxide should be avoided in these patients due to the potential of expanding emphysematous bullae, leading to rupture.

Question 8

What is the most potent stimulus for pulmonary vasoconstriction?

Answer 8

Hypoxia

Generalized alveolar hypoxia is the most potent stimulus for pulmonary vasoconstriction. When it occurs locally, it serves to shunt blood to areas that are better oxygenated. Systemic acidosis also promotes pulmonary vasoconstriction but is not as strong a stimulus as hypoxia.

Question 9

Which of the following statements regarding emphysema and bronchitis is not true?

Answer 9

Emphysema is associated with an elevated hematocrit

Chronic bronchitis is actually one of the two forms of COPD. Emphysema is the other form. Patients with chronic bronchitis typically exhibit frequent cough, copious sputum, an elevated hematocrit, increased markings (not hyperinflation) on chest x-ray, elevated PaCO2, normal elastic recoil, and increased airway resistance. In contrast, patients with emphysema have minimal sputum production with a less frequent cough, a normal hematocrit and PaCO2, decreased elastic recoil, hyperinflation on chest x-ray, and a normal to slightly increased airway resistance.

Question 10

The most common cause of respiratory distress syndrome in the premature infant is

Answer 10

insufficient surfactant production

Respiratory distress syndrome in premature infants is most commonly caused by a lack of surfactant production. Surfactant is not produced until about 28 weeks of gestation and doesn’t reach normal production until 35 weeks of gestation.

Question 11

You are preparing to induce a patient with a large anterior mediastinal mass for general anesthesia. Which device should you have at your immediate disposal?

Answer 11

Rigid bronchoscope

Patients with large anterior mediastinal masses are at risk for total airway obstruction even if spontaneous respirations are maintained. A rigid bronchoscope should be readily available in anticipation of this event. The anesthesia provider should also be prepared to turn the patient lateral or prone should airway collapse occur.

Question 12

What condition would produce the flow-volume loop shaded in pink? (top part is pushed down)

Answer 12

Tracheomalacia

A good example of a variable intrathoracic obstruction is tracheomalacia. It is referred to as variable because the lesion changes shape depending on whether the patient is in the inspiratory phase or the expiratory phase. Imagine there is a weakness in the tracheal wall inside the thorax. As the patient inhales, the weakness bulges out in the same direction that the lungs and chest wall expand. As the patient exhales, though, the pressure on the outside of the weakened area causes it to collapse and produce an obstruction. On the flow-volume loop, the inspiratory phase appears normal, but the expiratory phase exhibits an obstructive pattern.

Question 13

What condition would produce the flow-volume loop shaded in pink? ( bottom part pushed up)

Answer 13

Unilateral vocal cord paralysis

The flow-volume loop depicts a variable extrathoracic obstruction. A possible cause of a variable extrathoracic obstruction is unilateral vocal cord paralysis. It acts in the opposite manner of a variable intrathoracic obstruction like tracheomalacia. In this lesion, as the patient exhales, the cords passively open, allowing for the free flow of air. When the patient inhales, however, the paralyzed vocal cord is drawn downward and produces a decrease in the inspiratory flow. On the flow volume loop, this appears as a normal expiratory pattern with an inspiratory pattern that is chopped off.

Question 14

What would be the most appropriate initial intervention for intraoperative bronchospasm in a patient with a history of asthma?

Answer 14

propofol

Bronchospasm can occur intraoperatively due to a variety of reasons such as airway manipulation, pneumothorax, endobronchial intubation, aspiration, and anaphylaxis. If these factors can be eliminated, then the bronchospasm should be addressed first by deepening the anesthetic using propofol, ketamine, lidocaine, or increasing the inspired anesthetic. You should then increase the FiO2 to 100%, administer a beta-agonist, administer epinephrine (if severe), administer corticosteroids, and consider intravenous aminophylline.

Question 15

Manifestations of cor pulmonale include

Answer 15

Elevated pulmonary artery pressures

Cor pulmonale is a sequence of symptoms that originate with hypoxia due to pulmonary pathology, often COPD. The hypoxia results in hypoxic pulmonary vasoconstriction and elevated pulmonary artery pressures. In the face of pulmonary hypertension, the right ventricle can begin to fail resulting in prominent A waves on the central venous pressure, jugular venous distention, hepatosplenomegaly, peripheral edema and often a diastolic murmur due to incompetence of the pulmonary valve.

Question 16

The pulmonary circulation is considered to be what type of system?

Answer 16

low pressure, high volume

The pulmonary circulation is considered to be a low pressure, high volume system that can accommodate high blood flow and has a pressure about one-fifth that of the systemic circulation.

Question 17

Which condition would produce a flow-volume loop consistent with variable extrathoracic obstruction?

Answer 17

Unilateral vocal cord paralysis

With unilateral vocal cord paralysis, exhalation is normal. However, during inspiration, the paralyzed cord draws downward, obstructing inspiration. This produces a flow-volume loop with a normal expiratory component and an inspiratory component that appears truncated. This is consistent with variable extrathoracic obstruction.

Question 18

Which of the following statements about thoracoscopy is not correct?

Answer 18

It typically requires one small incision in the lateral chest

The patient is typically placed in the supine position. The video thoracoscope is inserted into a small incision so that the pleural cavity can be assessed. Several other small incisions are then made for the insertion of instruments. The instruments and the thoracoscope can be interchanged based upon the location of the problem. A double-lumen tube must be used so that the ipsilateral lung is collapsed and proper visualization of the pleural cavity is achieved. Hemorrhage, air embolism, air leak from lung, and damage to intrathoracic structures are potential complications.

Question 19

Which Reynolds number below would be most likely to represent predominantly turbulent flow?

Answer 19

4100

A Reynolds number greater than 4000 is indicative of predominantly turbulent flow. A value less than 2000 indicates predominantly laminar flow.

Question 20

Select two signs and symptoms of a gas embolism.

Answer 20

Two signs and symptoms of a gas embolism are: hypoxia and increased pulmonary artery pressures. Others include: pulmonary edema, cyanosis, tachycardia, hypotension, right ventricular strain pattern on the ECG, decreased end-tidal pressure of carbon dioxide, and increased end-tidal nitrogen.

Question 21

Which Reynold’s number is indicative of predominantly laminar flow?

Answer 21

1000.
A Reynolds number from 2000-4000 is considered a mix of turbulent and laminar flow and above 4000 is severely turbulent. A value less than 2000 indicates predominantly laminar flow.

Question 22

A surgeon has ordered cefazolin for preoperative antibiotic prophylaxis. However, the patient is allergic to cefazolin. Which antibiotics would be the most appropriate alternatives? (select two)

Answer 22

Clinda & Vanco
Both clindamycin and vancomycin can be administered safely. Cefazolin is a cephalosporin antibiotic; cefuroxime is in this same drug classification and would not be appropriate for this patient. Ketoconazole is an antifungal agent, not an antibiotic.

Question 23

Chronic or recurrent excessive mucus secretion for at least three months a year for two consecutive years is the defining characteristic of

Answer 23

chronic bronchitis
Chronic or recurrent excessive mucus secretion for at least three months a year for two consecutive years is the defining characteristic of chronic bronchitis.

Question 24

Which of the following conditions is consistent with a diagnosis of adult respiratory distress syndrome?

Answer 24

Pulmonary artery wedge pressure less than 18 mmHg
For a patient to meet the diagnosis of Adult Respiratory Distress Syndrome (also known as Acute Respiratory Distress Syndrome), four criteria must be met: acute onset, PAO2 to FiO2 ratio <200 regardless of the level of PEEP applied, bilateral infiltrates on chest x-ray, and a PA wedge pressure less than or equal to 18 mmHg.

Question 25

The normal V:Q ratio for the entire lung is about

Answer 25

0.8
The V:Q ratio is the volume of ventilation divided by the volume of pulmonary blood flow. For example, the normal pulmonary ventilation is about 4 liters per minute. The normal pulmonary blood flow is about 5 liters per minute. That means that the normal V:Q ratio for the entire lung is 0.8.

Question 26

Which benzodiazepine is most associated with pain on injection?

Answer 26

Diazepam
Diazepam is most associated with pain on injection. Zolpidem (Ambien) is a nonbenzodiazepine GABA-A receptor modulator. Always read the question carefully and determine if any descriptors such as classification or category exclude a distractor.

Question 27

Which is an excessive posterior curvature of the spine that usually occurs in the thoracic region?

Answer 27

Kyphosis

Kyphosis is an excessive posterior curvature (or hump) usually of the thoracic spine.

Question 28

Gas exchange occurs in the airways across which type of cells?

Answer 28

Squamous epithelium
The mucosa in the airway gradually transitions from ciliated columnar epithelium to cuboidal epithelium and finally to thin, squamous epithelium where gas exchange occurs.

Question 29

Most of the carbon dioxide carried in the blood is in the form of

Answer 29

bicarbonate ions
About 5 percent of the carbon dioxide transported in the blood is in physical solution in the blood. Another 5 percent is carried by hemoglobin. The remaining approximately 90 percent is in the form of bicarbonate ions.

Question 30

The physiologic characteristics of hypoxic pulmonary vasoconstriction include:

Answer 30

It may be inhibited by verapamil
Hypoxic pulmonary vasoconstriction is a localized reaction that occurs and resolves quickly in response to episodes of hypoxia within the lungs. It occurs due to alveolar hypoxia, not arterial hypoxemia. It may be inhibited by calcium channel blockers, nitrates, and inhalational anesthetics.

Question 31

What nerve provides motor innervation to the cricothyroid muscle?

Answer 31

external branch of the superior laryngeal nerve
The superior laryngeal nerve is divided into two branches: the internal branch and the external branch. The internal branch provides sensory innervation to the posterior epiglottitis, the arytenoids, and the vocal cords. The external branch provides motor innervation to the cricothyroid muscle.

Question 32

A patient has forcefully expired all the air in their lungs. The amount of air above the residual volume that is left in the lungs at the moment the small airways begin to collapse is referred to as the

Answer 32

closing volume

Closing volume is the volume of air above the residual volume that is left in the lungs at the moment the small airways begin to close or collapse.

Question 33

The recurrent laryngeal nerves are branches of the

Answer 33

vagus nerve

The pair of recurrent laryngeal nerves (also known as the inferior laryngeal nerves) originate from the vagus nerve. The left recurrent laryngeal nerve passes under the aortic arch and travels back up alongside the trachea. The right recurrent laryngeal nerve passes under the right subclavian artery before returning back up towards the larynx.

Question 34

Which of the following cartilages of the larynx occurs as a pair?

Answer 34

Arytenoid
The individual cartilages of the larynx are the thyroid, epiglottis, and cricoid. The paired cartilages are the arytenoid, corniculate, and cuneiform.

Question 35

Factors known to inhibit hypoxic pulmonary vasoconstriction include: (select four)

Answer 35

inhalation anesthetics
very low pulmonary artery pressures
very high mixed venous PO2
nitroprusside infusion

Factors that inhibit hypoxic pulmonary vasoconstriction include: inhalation anesthetics, very high or very low pulmonary artery pressures, hypocapnia, beta-adrenergic agonists, vasodilators such as nitroglycerin and nitroprusside, pulmonary infection, high or very low mixed venous PO2, and calcium channel blockers.

Question 36

A trauma patient exhibits tracheal deviation, significant hypotension, hypoxia, tachycardia, and diminished breath sounds on one side of the chest. You suspect a tension pneumothorax. The most appropriate intervention is

Answer 36

perform a needle decompression

A tension pneumothorax is a potentially lethal situation and should be addressed immediately. The chest can be decompressed by inserting a 14-gauge angiocath into the 2nd or 3rd anterior interspace over the affected side or through the 4th or 5th interspace if approached laterally. A rush of air will be noticed when the needle enters the thorax.

Question 37

Approximately what percentage of pulmonary blood flow goes to the dependent lung in a healthy, mechanically-ventilated patient in the lateral decubitus position?

Answer 37

60%

During two-lung ventilation, about 60% of the pulmonary blood flow goes to the dependent lung.

Question 38

A patient is in postanesthesia recovery following a thoracotomy. Which of the following would necessitate returning to the operating room for surgical exploration?

Answer 38

Chest tube drainage greater than 200 cc/hour

Chest tube drainage more than 200 cc/hour warrants returning to the operating room. Typically, blood draining into chest tubes from the pleural space is less than 500 cc/day.

Question 39

You administer scopolamine preoperatively to an elderly patient. The patient becomes agitated, confused, and severely obtunded. Which drug would be the most appropriate agent to alleviate these symptoms?

Answer 39

physostigmine

The patient is exhibiting signs of central nervous system toxicity (central anticholinergic syndrome). Atropine and scopolamine can both cause this syndrome. Physostigmine 1-2 mg IV would be the appropriate drug to treat this.

Question 40

What is the most common cardiac abnormality associated with severe scoliosis?

Answer 40

Mitral valve prolapse

Mitral valve prolapse is the most common cardiac abnormality associated with scoliosis.

Question 41

A patients arterial blood gas results reveal the following data: pH 7.51, PCO2 38, HCO3 30, PO2 92. How would you interpret this information?

Answer 41

Metabolic alkalosis

The pH is above 7.4 which indicates that this is an alkalosis. The bicarbonate level is elevated indicating that the disturbance is metabolic in origin.

Question 42

What condition would produce the flow-volume loop shaded in pink? (click the Exhibit button to view the image) (fixed)

Answer 42

Tracheal stenosis

A fixed airway obstruction can be caused by a foreign body in the airway, a lesion like tracheal stenosis, or anatomical compression by a tumor or goiter. In a fixed obstruction, the flow-volume loop exhibits decreased flow during both inspiration and expiration. It looks as if the top and bottom of the loop are chopped off.

Question 43

You are preparing to perform anesthesia for a patient undergoing a thoracoscopic sympathectomy for hyperhidrosis. You anticipate this patient will be positioned

Answer 43

Supine

Thoracoscopic sympathectomy for hyperhydrosis is performed in the supine position. It is an outpatient procedure and involves no chest tubes.

Question 44

What are the elements of Virchow’s triad? (select three)

Answer 44

hypercoagulability
venous stasis
vessel wall abnormalities

Virchow’s triad is a set of three factors that predict a high risk for pulmonary embolism. Virchow’s triad includes hypercoagulability, venous stasis, and vessel wall abnormalities.

Question 45

What nerve provides sensory innervation to the posterior epiglottitis, the arytenoids, and the vocal cords?

Answer 45

The internal branch of the superior laryngeal nerve

The superior laryngeal nerve is divided into two branches: the internal branch and the external branch. The internal branch provides sensory innervation to the posterior epiglottitis, the arytenoids, and the vocal cords. The external branch provides motor innervation to the cricothyroid muscle.

Question 46

Which condition will exhibit a decreased peak expiratory flow rate in a flow-volume loop?

Answer 46

COPD

COPD will produce a flow-volume loop that is shorter (reduced peak flow rate) and smaller. The peak flow in restrictive conditions such as sarcoidosis or pulmonary fibrosis will appear normal or even heightened. Unilateral vocal cord paralysis exhibits a normal peak expiratory flow rate and a truncated inspiratory flow.

Question 47

What are the most common double-lumen tube sizes used for male patients?

Answer 47

39.0-41.0

The most common double-lumen tube sizes used in male patients are 39-41 French.

Question 48

Factors that are associated with an increased risk for the development of deep vein thrombosis and pulmonary embolism include: (select four)

Answer 48

Obesity
Estrogen therapy
Prolonged immobilization
Pregnancy

Factors associated with an increased risk for the development of DVT and PE include obesity, advanced age, major surgical procedures lasting longer than 30 minutes, hereditary thrombophilias, spinal cord injury, malignancy, previous thromboembolism, estrogen therapy, pregnancy, and prolonged immobilization.