Chapter 28 Ophthalmology and Otolaryngology
Ophthalmology
1. What is normal intraocular pressure (IOP)?
2. How is IOP created and maintained?
3. Why and to what extent does IOP increase during coughing or vomiting?
4. What factors during the course of a general anesthetic increase IOP?
5. What physiological factors (CO2, temperature) during the course of a general anesthetic decrease IOP?
6. How does ketamine affect intraocular pressure? What other attributes of ketamine make it a less than ideal choice for anesthesia in patients undergoing ophthalmologic procedures?
7. How much does IOP increase with the intravenous administration of succinylcholine? What is the duration of this effect?
8. What is the mechanism for the increase in IOP following administration of succinylcholine?
9. What maneuvers may attenuate the rise in IOP associated with succinylcholine use for laryngoscopy and intubation?
10. How do paralyzing doses of nondepolarizing neuromuscular blocking drugs affect intraocular pressure?
11. How do inhaled anesthetics affect IOP? What is the effect on IOP of most intravenous anesthetics?
12. How do changes in arterial blood pressure affect IOP?
13. What topical ophthalmic medicines may be absorbed sufficiently to exert systemic effects?
14. What systemic effects have been attributed to the use of topical ophthalmic β-adrenergic blocking medications?
15. What are the systemic effects of topical phospholine iodide (echothiophate)?
16. Why is phenylephrine administered as a topical ophthalmic medicine? What systemic effect has been attributed to the topical ophthalmic application of this drug?
17. Why are carbonic anhydrase inhibitors, such as acetazolamide, administered as topical ophthalmic medicines? What systemic effects have been attributed to the topical ophthalmic application of this drug?
18. What is the oculocardiac reflex? What is its reported incidence? When is it most likely to occur?
19. When is the oculocardiac reflex most often encountered?
20. What cardiac rhythms are likely to result from the oculocardiac reflex?
21. How does arterial hypoxemia or hypercarbia affect the oculocardiac reflex? How does the depth of general anesthesia affect the oculocardiac reflex?
22. What is the first line of treatment of the oculocardiac reflex? What measures may be taken if the reflex persists?
23. Is prophylactic use of anticholinergics fully effective in preventing the oculocardiac reflex? What problems may arise from use of an anticholinergic?
24. What are some important demographic characteristics of patients scheduled for eye surgery?
25. Should antiplatelet or anticoagulant medications be discontinued prior to surgery?
26. What is a key anesthetic consideration for the patient scheduled for ophthalmic surgery with uncontrolled cough, untreated Parkinsonian tremor, severe claustrophobia, or pathological anxiety?
27. What are the anesthetic options for patients having eye surgery?
28. What is the significance of the extraocular muscle cone for eye blocks?
29. What is the ultimate needle tip position for a retrobulbar (intraconal) block?
30. What is the rationale behind extraconal (peribulbar) anesthesia? Where is the ultimate needle tip position?
31. What are some complications of a retrobulbar block?
32. What is the differential diagnosis of altered physiological status (blood pressure, heart rate) after a needle-based ophthalmic regional eye block?
33. How does a sub-Tenon block differ from a needle-based eye block?
34. Which patients are at high risk for retinal detachment?
35. What are the anesthetic considerations for patients undergoing surgery to repair a retinal detachment?
36. When must nitrous oxide be avoided as maintenance anesthetic for patients undergoing surgery to repair a retinal detachment? What is the risk associated with this?
37. What is glaucoma? What are its variants?
38. What are the anesthetic goals in the management of glaucoma patients?
39. What are some special anesthetic considerations in children undergoing strabismus surgery?
40. What is the most common reason for an inpatient admission for children following strabismus surgery?
41. What factors must be considered in the anesthetic management of patients with traumatic eye injuries?
42. Why is “awake” endotracheal intubation hazardous for patients with open globe injuries?
43. What anesthetic maneuvers may attenuate increases in IOP in traumatic eye injury?
44. Is regional anesthesia contraindicated in traumatic eye injuries?
45. What is the most common ocular complication following general anesthesia for non-ophthalmologic surgery? What other condition can mimic it?
46. Why are patients who are undergoing a surgical procedure via general anesthesia at risk for corneal abrasion?
47. What are clinical signs of corneal abrasion?
48. What are some measures that can be taken to reduce the risk of corneal abrasion in patients under general anesthesia? What are some of the potential problems with routine use of ophthalmic ointment?
49. Which surgical procedures are associated with increased risk of postoperative visual loss?
50. What action(s) should be taken if the patient complains of postoperative visual loss?
Otolaryngology
51. What special airway considerations pertain to ENT surgery?
52. Why are posterior pharyngeal packs used during ENT surgery and what precautions are required with their use?
53. What supplemental airway devices may be needed for a difficult airway during ENT surgery?
54. What is laryngospasm? How is the reflex mediated?
55. What is the treatment for laryngospasm?
56. Why are children at particular risk for laryngospasm?
57. Should scheduled ENT surgery be postponed if the child has an upper respiratory infection (URI)? What are the risks associated with proceeding with anesthesia in a child with an active upper respiratory infection?
58. What risks are associated with general anesthesia in a patient with massive epistaxis?
59. What are some symptoms that may alert the anesthesiologist to the presence of obstructive sleep apnea (OSA)?
60. What features may be noted in the airway examination of a patient with OSA?
61. What are the anesthetic implications of OSA?
62. What elements are necessary to generate an airway fire?
63. Are airway fires possible with monitored anesthesia care (MAC)?
64. What are the main anesthetic considerations for middle ear surgery?
65. What effects may nitrous oxide (N2O) exert during ear surgery?
66. How is surgical identification of the facial nerve performed intraoperatively in patients undergoing otologic surgery? How might this affect the anesthetic management?
67. Why do otolaryngologists use epinephrine intraoperatively? What are the anesthesia implications of its use?
68. What concentration of epinephrine is considered safe in ear microsurgery?
69. During otolaryngology surgery how can bleeding in the surgical field be minimized?
70. What is an optimal anesthetic plan for emergence from general anesthesia in the patient who has undergone middle ear surgery?
71. Why are patients who have undergone middle ear surgery at risk for postoperative nausea and vomiting?
72. What anesthetic strategies minimize postoperative nausea and vomiting after ear surgery?
73. What factors contribute to airway obstruction in children undergoing tonsillectomy and adenoidectomy?
74. What is negative pressure pulmonary edema?
75. Why is blood loss often underestimated during and after tonsillectomy and adenoidectomy?
76. What are some considerations for the anesthetic management of patients who return to surgery because of significant bleeding after tonsillectomy and adenoidectomy?
77. What organism is frequently responsible for acute epiglottitis?
78. What are the clinical features of acute epiglottitis?
79. What anesthetic precautions are necessary in acute epiglottitis management?
80. What are the clinical features of foreign body aspiration into the airway?
81. What anesthesia precautions are necessary in addressing the patient with an airway foreign body?
82. What postoperative measures are necessary after the removal of a foreign body from the airway?
83. Why has cocaine been used for nasal surgery?
84. What are the disadvantages of using cocaine? Are there alternatives?
85. What considerations are important for general anesthesia emergence in nasal and sinus surgery?
86. What preoperative investigations may be useful in a patient undergoing endoscopic surgery?
87. What techniques may be used to maintain ventilation and oxygenation during airway endoscopy?
88. What risk is associated with the use of a manual high-pressure jet ventilator (Sanders’ injector apparatus)?
89. What is a laser? What advantages does it offer for surgical procedures?
90. Name some hazards that are associated with laser surgery.
91. What is the purpose of a smoke evacuator used during laser surgery?
92. What measures can be taken during laser surgery to minimize the risk of an endotracheal tube fire?
93. Why should the ETT cuff be filled with saline or an indicator dye during laser surgery?
94. What medical issues are frequently encountered in patients undergoing radical neck dissection?
95. How does a history of radiation to the larynx, pharynx, or oral cavity affect anesthetic management?
96. What arrhythmias may be precipitated during radical neck dissection, and why?
97. What known injuries may be encountered postoperatively after radical neck dissection?
98. What catastrophic postoperative event may occur after neck surgery?
99. How may hypocalcemia present after thyroid surgery?
100. The patient is unable to grimace after a parotidectomy. Why? What monitor(s) may help prevent this complication?
Answers*
Ophthalmology
1. Intraocular pressure ranges between 10 to 22 mm Hg. In the intact normal eye there is a typical diurnal variation of 2 to 5 mm Hg. Small changes can occur with each cardiac contraction and with closure of the eyes, mydriasis, and changes in posture. (487)
2. Intraocular pressure is primarily a balance between the production of aqueous humor and its drainage. Aqueous humor is actively secreted from the posterior chamber’s ciliary body and flows through the pupil into the anterior chamber where it becomes mixed with aqueous fluids, which are passively produced by blood vessels on the iris’s forward surface. (487)
3. Any obstruction of venous return from the eye to the right side of the heart can raise IOP. Coughing or straining can increase intraocular pressure by 40 mm Hg or more. (487)
4. Any maneuver that increases venous congestion will increase IOP. These include: Trendelenburg positioning, tight cervical collar, straining, retching, vomiting, and coughing. Direct laryngoscopy and intubation also increase intraocular pressure. (487)
5. During general anesthesia hyperventilation and hypothermia decrease IOP. (487)
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