ENT Flashcards

Question

25. Fifteen minutes after the start of surgery, while the surgeon is retracting the medial rectus muscle, the patient becomes hypotensive and bradycardic. The first-line therapy to address this cardiovascular derangement is A. Atropine 1 mg IV B. Phenylephrine 100 μg IV C. Ask the surgeon to stop D. Glycopyrrolate 1 mg IV

Answer 1

C.The oculocardiac reflex best explains this cardiovascular presentation during ophthalmologic surgeries. First-line therapy is always to remove the stimulus, which is mediated via trigeminal afferents.

Answer 2

26. B.Hypertensive episodes during anesthesia should be tackled logically. Common causes are light anesthesia, hypoxia, and hypercarbia. In this case, excessive systemic uptake of the phenylephrine precipitated severe hypertension. Elevated diastolic pressures with ECG pathology necessitate immediate action to prevent further cardiovascular decline. Administration of sodium nitroprusside is beneficial to quickly reduce the blood pressure and decrease cardiac afterload.

Answer 3

27. D.Corneal abrasions produce a foreign body sensation with associated tearing, conjunctivitis, and photophobia. This pain is made worse by blinking. Protection against this occurrence includes application of nonionic petroleum-based ophthalmic ointment to the eye, securely taping the eyelids shut during anesthesia, and discouraging patients from rubbing their eye on emergence. Abrasions can be diagnosed by fluorescein staining, and treatment options include saline flushes, antibiotic ointment, and patching the eye.

Answer 4

28. A.Laryngospasm can complicate any routine airway management and is especially prevalent around the time of extubation. It often occurs during stage 2—“excitement stage”—of general anesthesia in combination with an airway irritant such as blood, mucus, laryngoscope blade, suction catheter, surgical debris, or other foreign objects. This protective reflex is mediated by the superior laryngeal nerve and manifested as sustained closure of the glottis. Laryngospasm with complete airway obstruction can be associated with negative pressure pulmonary edema, as patients can create a significant amount of negative intrathoracic pressure during attempts to breathe against an obstructed upper airway. The management consists of positive pressure ventilation, increasing the depth of anesthesia, and occasionally a small dose of a muscle relaxant with or without reintubation.

Answer 5

29. A.Tracheal intubation to facilitate mechanical ventilation is common in ICU patients to appropriately manage failure of adequate spontaneous ventilation and/or oxygenation. Both nasal and oral tracheal tubes are relatively safe, for at least several weeks, while patients convalesce. When compared with prolonged oral intubation, nasotracheal intubation may be more comfortable for the patient, more secure (fewer occurrences of accidental self-extubations), and less likely to cause laryngeal damage. Nasal intubation, however, has its own significant adverse events, including significant nasal bleeding, transient bacteremia, sinusitis, and otitis media (from obstruction of the auditory tubes).

Answer 6

30. C.Recognizing the anatomical differences between an adult and a pediatric airway is important. One of the most obvious differences is the tongue itself. The pediatric tongue is larger, in relation to the amount of free space in the oropharynx, when compared to the adult tongue. With regards to the pediatric epiglottis, it tends to be large and floppy with a more oblong configuration, making epiglottis control with a laryngoscope blade more challenging. Additionally, the position of the adult larynx is at about the level C5–C6; the pediatric larynx is more cephalad, at about the level of the C3–C4. This is an important anatomical airway consideration, since the higher larynx tends to be more anterior as well (Fig 16-2).

Answer 7

31. A.Laryngospasm associated with airway manipulation is more likely to occur in the presence of a URI such that surgery is typically postponed until resolution of symptoms, typically 1 to 2 weeks. Young children, however, have frequent URIs such that risk:benefit ratio should be considered when determining appropriateness of proceeding versus further postponement.

Answer 8

32. D.Hemorrhage from a bleeding tonsillar bed in the postoperative period is a hazardous complication. Her vitals reveal hypovolemia and as such, initial management should be to resuscitate the patient prior to returning to the operating room to minimize morbidity associated with anemia and hypovolemia in the setting of repeat general anesthesia.

Answer 9

33. C.Anesthesia during laser surgery may be administered with or without an endotracheal tube. If intubation is needed, appropriate laser-resistant endotracheal tubes should be utilized. In this regard, remember that all PVC tubes are flammable and can ignite when contacted by the laser beam. Using the laser intermittently, ventilating the patient with a low concentration of combustible gases, along with protecting adjacent tissues with saline-soaked sponges are all appropriate approaches to minimize the fire hazards.

Answer 10

34. D.Airway fires are an inherent risk with laser surgery, such that a plan of action should be considered before the case begins. The cuff of the endotracheal tube may be filled with saline, as opposed to air, to minimize flammability should the laser beam rupture the cuff. Inspired oxygen concentration is minimized as tolerated (usually Fio 2 of <0.50), as oxygen readily supports combustion. In the event of an airway fire, the anesthesia circuit should be immediately disconnected to interrupt further delivery of oxygen, followed by removal of the tube from the patient’s airway. If the flame persists, the field should next be flooded with normal saline.

Answer 11

35. B.Post airway fires, it is most appropriate to leave the patient intubated for continued observation as the presence of laryngeal and pharyngeal edema can result in failed extubation. Therefore, this patient should be reintubated with a regular endotracheal tube and monitored for the next 24 hours. Corticosteroids can be considered for severe edema with absent cuff leak, but generally is not given prophylactically.

Answer 12

36. B.The mixture of gases delivered into the endotracheal tube may affect the risk of combustion during general anesthesia and laser surgery of the airway. N 2 O is highly combustible and should be strictly avoided. Fio 2 should be reduced to as low as possible with an air–oxygen mixture. Helium, if available, is ideal as it is inert and noncombustible. Though N 2 is also considered safe, the mean time to ignition with nitrogen has been found to be significantly shorter when compared to the same concentration of helium.

Answer 13

37. C.In 1960s, Sanders described ventilation technique using a 16-gauge jet placed down the side arm of a rigid bronchoscope, relying on air entrapment to continue oxygenation with an open bronchoscope. An intermittent jet of oxygen administered from a high-pressure source (50 psi) entrains room air to maintain supranormal oxygen concentrations in the upper airways, which creates a diffusion gradient to the alveolar spaces. This gradient is maintained as alveolar oxygen is constantly consumed.

Answer 14

38. C.Apneic oxygenation relies on mass movement oxygenation. With the onset of apnea, a low pressure develops in the airspace of the lungs, as more oxygen is absorbed (230 mL/min) than CO 2 is released (200 mL/min). If the airways are open, 100% oxygen supplied to the upper airways will follow the pressure gradient and flow into the lungs, replacing the oxygen consumed. The uptake of oxygen into the blood will then remain at relatively normal levels, recognizing that the lack of ventilation will eventually cause marked hypercapnia and acidosis.

Answer 15

D.The configuration of the flow–volume curve during spirometry testing can be used to demonstrate abnormalities of the larger central airways (larynx, trachea, and main stem bronchi). The FEV 1 /FVC ratio can provide diagnostic value, as disproportionate reduction in the FEV 1 as compared to the FVC is the hallmark of obstructive lung diseases. Concern should be made regarding airway collapse following sedation or induction of anesthesia when extrathoracic lesions are present. If long-standing, tracheomalacia may leave the trachea weak and collapsible postoperatively (Fig 16-3).

Answer 16

40. A.Anesthesia of the nasal mucosa and nasopharynx is achieved via blockade of trigeminal branches, particularly the sphenopalatine ganglion and ethmoid nerves. Blockade of the glossopharyngeal and superior laryngeal nerves provide anesthesia to the mouth, oropharynx, and base of the tongue. The hypopharynx, larynx, and trachea are innervated via a branch of the vagus nerve (CN X), specifically the recurrent laryngeal nerve, which can be blocked via a transtracheal approach. On the other hand, blockade of the hypoglossal nerve (CN XII) will only serve to paralyze the intrinsic muscles of the tongue without adding to anesthesia of the airway (Fig 16-4).

Answer 17

41. A.Inspection of the neck is generally considered the first step, asit may reveal a life-threatening and reversible cause of airway obstruction such as a compressing hematoma. Direct visualization of vocal cords may point toward recurrent laryngeal nerve damage contributing to dyspnea. Though hypocalcemia due to removal of the parathyroid glands can occur, signs and symptoms will usually present much later in the perioperative course (24–96 hours), and unlikely to be contributing to dyspnea in the PACU. Inhaled racemic epinephrine is commonly used when stridor is present after extubation.

Answer 18

42. B.The recurrent laryngeal nerves provide motor innervation to all the intrinsic muscles of the larynx, except the cricothyroid muscle, which is innervated by the superior laryngeal nerve. Damage to bilateral recurrent laryngeal nerves will affect abduction and adduction of the cords, resulting in both vocal cords adopting an intermediate, or paramedian, position. Patient would also have associated aphonia with risk of airway obstruction with inspiration as the cords flap together. Unilateral damage will present with hoarseness.

Answer 19

43. B.In the case of lesions to the SLNs, adduction and abduction of the vocal cords remain intact. SLN lesions instead lead to weak tensor strength (cricothyroid muscle), leaving the voice hoarse, weak, breathy, and with the inability to scream or shout. Other associated findings would be loss of sensation above the cords, leaving patient vulnerable to inhalation of any material present in the pharynx.

Answer 20

44. A.Blunt-neck trauma is most commonly a result of a motor vehicle collision associated with rapid acceleration or deceleration injuries, which may include crushing injuries of the trachea, esophagus, vascular structures, and cervical spine. A laryngeal fracture can lead to life-threatening airway obstruction and as such should be treated in an emergent manner. Signs and symptoms of dyspnea, emphysema, and inability to lie flat reflect a fragile airway. Definitive airway management following airway trauma is a surgical airway, most commonly a tracheostomy. Cricothyroidotomy is not recommended following laryngotracheal injuries, as the landmarks are usually difficult to assess, since the cricoid is often the level of the injury.

Answer 21

45. B.The neck is divided into three zones: zone I, including the thoracic inlet, up to the level of the cricothyroid membrane, is treated as an upper thoracic injury. Zone III, above the angle of the mandible, is treated as a head injury. In this case, fracture of the thyroid cartilage represents an injury of the neck in zone II. For ease of memory, consider that the cricoid cartilage demarcates the border between zones I and II and the angle of the mandible separates zone II from zone III (Fig 16-5).

Answer 22

46. D.Increasing EtCO 2 andtemperature may reveal possible malignant hyperthermia. With onset of cardiac arrhythmias, and the increasing likelihood of the development of malignant hyperthermia with rapidly climbing EtCO 2 and hyperthermia, treatment with dantrolene should be considered and pursued. Other signs that can strengthen the diagnosis are muscle rigidity and myoglobinuria.

Answer 23

47. A.More than 30 different mutations are linked to malignant hyperthermia susceptibility. Genetic testing is available to establish a diagnosis, but the CHCT remains the criterion standard.

ENT Flashcards

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