PATIENT SEDATION AND PAIN MANAGEMENT
28
Charles T. Lau, MD, and
S. William Stavropoulos, MD
1. What is the purpose of sedation and pain management during an interventional
radiology procedure?
The purpose is to enable a patient to tolerate a potentially painful procedure yet still maintain satisfactory
cardiopulmonary function and the ability to cooperate with verbal commands and tactile stimuli.
2. What is the difference between analgesia and anesthesia?
Analgesia is the relief of pain without alteration of a patient s state of awareness. Anesthesia is the state
of unconsciousness.
3. What is the difference between anxiolysis and amnesia?
Anxiolysis is the relief of fear or anxiety without alteration of awareness. Amnesia is the loss of memory.
4. What capabilities should the patient maintain during conscious sedation?
The patient should:
" Remain responsive and cooperative.
" Maintain spontaneous ventilation.
" Be able to protect the airway.
" Maintain protective reflexes.
5. Describe the levels of patient sedation.
The levels of patient sedation exist along a continuum: light sedation, moderate sedation, deep sedation, and general
anesthesia. A patient under light sedation can respond to stimuli and maintains intact airway reflexes. A patient under
moderate sedation should maintain spontaneous ventilation and be able to protect the airway. A patient under deep
sedation can respond to vigorous stimuli, but may lack airway reflexes. A patient under general anesthesia has no
response to stimuli and lacks all protective reflexes.
6. List the details that should be included in the presedation evaluation of a patient.
" Patient medical history
" Previous adverse experience to sedation or anesthesia
" Current medication use and drug allergies
" Time and nature of last oral intake
" History of alcohol or substance abuse
" Focused physical examination including heart, lungs, and airway
" Pertinent clinical laboratory findings
7. How long should a patient typically fast before undergoing conscious sedation?
A patient should not have solid foods for 6 to 8 hours and clear liquids for 2 to 3 hours before undergoing
sedation.
8. The physical status of a patient is often quantitated on a 5-point scale, known
as the American Society of Anesthesiologists Physical Assessment Status.
Describe this scale.
" Class I: Healthy patient
" Class II: Mild to moderate systemic disturbance, well controlled
" Class III: Severe systemic disturbance that limits normal activities
" Class IV: Severe life-threatening illness
" Class V: Moribund, poor chance for survival
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9. Commonly, conscious sedation is administered by the provider (e.g., interventional
radiologist) with patient monitoring provided by a qualified nurse. What patient
factors should influence a provider to consider consulting an anesthesiologist to
administer conscious sedation?
Patient factor should include:
" ASA classification of III, IV, or V.
" Obesity.
" Pregnancy.
" Mental incapacity.
" Extremes of age.
10. What patient factors must be monitored during conscious sedation?
Level of consciousness, ventilation, oxygenation, and blood pressure should be monitored, along with continuous cardiac
monitoring.
11. What equipment must be present when administering conscious sedation to
a patient?
A patient undergoing conscious sedation should be under direct observation until recovery is complete. Equipment
needed to monitor oxygenation; blood pressure; and heart rate, rhythm, and waveform should be present.
Pharmacologic antagonists and commonly used agents, supplemental oxygen, a defibrillator, and appropriate equipment
to establish airway and provide positive-pressure ventilation need to be at hand.
12. What pharmacologic agents are commonly used for patients undergoing conscious
sedation? What is their reversal agent?
Benzodiazepines are typically used to provide conscious sedation. Common benzodiazepines include midazolam,
lorazepam, and diazepam. Flumazenil is used as a reversal agent for benzodiazepines. The effect of flumazenil is usually
visible in 2 minutes, with peak effects at 10 minutes. In adults, an initial dose of 1 mg may be needed.
13. What are the usual effects of benzodiazepines?
Benzodiazepines produce sedation and amnesia, but do not provide analgesia. Significant adverse effects of
benzodiazepines include respiratory and cardiovascular depression. Paradoxic reactions can occur with benzodiazepines
and are more common in the elderly.
14. What pharmacologic agents are commonly used for pain control? What is their
reversal agent?
Opiates are commonly used to provide pain control. Commonly used opiates include fentanyl, morphine, and meperidine.
Naloxone is used as a reversal agent for opiates and is typically administered as 0.4-mg intravenous doses (in adults)
to a total of 2 mg. The effect of naloxone is usually visible in 2 to 3 minutes; however, its duration of action may be
substantially shorter than many long-acting opiates, and repeated dosing may be necessary.
15. What are the typical effects of opiates?
Opiates provide systemic analgesia, mild anxiolysis, and mild sedation. Opiates do not induce amnesia.
16. What pharmacologic agent used for pain control is contraindicated in patients taking
a monoamine oxidase (MAO) inhibitor?
Meperidine administered to patients taking MAO inhibitors can cause various undesirable and potentially lethal side
effects and is contraindicated. Side effects include agitation; fever; and seizures progressing in some instances to coma,
apnea, and death. The narcotic analgesic of choice for patients taking MAO inhibitors is morphine.
17. What are the strategies for dealing with a patient who has a known hypersensitivity
to iodinated contrast agents?
Adverse reactions to iodinated contrast agents range from nuisance side effects, such as hives and emesis, to
potentially lethal reactions, such as anaphylaxis and laryngeal edema. Patients with a history of even a minor
hypersensitivity reaction to contrast agent may be at increased risk for a severe reaction, and special precautions
should be exercised when administering contrast agent to these patients. Premedicating the patient with oral steroids
and the use of low-osmolar contrast agents may reduce the risk of minor reactions, but there is no proof that this
strategy prevents or reduces the risk of lethal contrast agent reactions. Alternative contrast agents, such as gadolinium
or CO2 or both, may be used in patients with a history of severe contrast agent reactions. If an iodinated contrast agent
must be used in a patient with a history of bronchospasm, laryngeal edema, or anaphylaxis, it may be wise to have an
anesthesiologist standing by.
INTERVENTIONAL RADIOLOGY 215
18. List possible options for the management of an acute vasovagal reaction.
A rapid infusion of normal saline or atropine (0.6 to 1 mg) may be given intravenously.
19. What are the ABCs of patient resuscitation?
Advanced Cardiac Life Support (ACLS) guidelines provide a series of algorithms regarding distressed patients in various
clinical settings. The ABCs of resuscitation is a part of these algorithms. Intervention in a patient with an unstable
condition should always begin with the establishment of an Airway, followed by assessment of Breathing (ventilation)
and Circulation (heart rate and blood pressure).
20. Describe the management of acute hypotension.
Remember your ABCs! During conscious sedation, an overdose of either a benzodiazepine or an opiate may cause
respiratory depression that manifests as acute hypotension. Vigorous stimulation (sternal rub) may remedy the situation.
If not, pharmacologic reversal may be needed. If hypoxia is not the etiology of the hypotension, evaluation of a patient s
heart rate provides a simple algorithm for treating acute hypotension. A vasovagal reaction should be suspected if the
patient is bradycardic, and treatment should proceed accordingly. If the patient is tachycardic, one should immediately
evaluate for a source of blood loss. A fluid challenge with normal saline may help determine whether a patient has
intravascular volume depletion. Pharmacologic intervention with epinephrine, phenylephrine, or dopamine may be
indicated if the patient fails to respond to the fluid challenge. A complete algorithm for treating hypotension can be
found in the ACLS guidelines.
21. List possible options for the management of an acute hypertensive crisis.
During a procedure, pain and anxiety may precipitate hypertension. A benzodiazepine, such as midazolam (Versed),
mixed with an opiate, such as fentanyl, is likely to decrease the blood pressure of an uncomfortable or anxious patient.
To treat a patient in true hypertensive crisis further pharmacologic intervention may be needed. Intravenous labetalol,
given as a bolus or a constant infusion, often normalizes blood pressure. Hydralazine and nitroprusside are other
intravenous agents that may also be useful in this setting.
Key Points: Patient Sedation and Pain Management
1. A patient under moderate sedation should maintain spontaneous ventilation and be able to protect the airway.
2. The following equipment should be present when administering conscious sedation: pharmacologic
antagonists, appropriate equipment to establish airway and provide positive-pressure ventilation, supplemental
oxygen, and a defibrillator.
3. The medications used to treat an anaphylactic reaction include diphenhydramine, methylprednisolone, and
epinephrine.
4. Naloxone is used as a reversal agent for opiates.
5. Flumazenil is used as a reversal agent for benzodiazepines.
6. ACLS guidelines provide complete recommendations for the distressed patient.
7. Evaluation of a patient with an unstable condition should always begin with the ABCs.
22. How can acute pulmonary edema be managed?
Pulmonary edema interferes with the ability to oxygenate blood. Therapy consists of securing an airway, providing
supplemental oxygen, and administering intravenous furosemide or other agents to induce diuresis.
23. Describe the immediate options for management of an anaphylactic reaction.
An anaphylactic reaction can be rapidly fatal. An airway should be secured immediately, and oxygen should be
administered. The mainstay of therapy consists of epinephrine (1:1000), 0.1 to 0.3 mL given subcutaneously every
15 minutes up to 1 mL total. Additional therapy includes saline for pressure support, diphenhydramine (50 mg
intravenously), methylprednisolone (50 mg intravenously), and dopamine (5 to 10 źg/kg/min intravenously).
Cardiopulmonary resuscitation may be required.
24. Describe the immediate options for management of acute laryngeal edema.
Laryngeal edema may lead to airway obstruction and death. An airway should be established, and oxygen should be
administered. Epinephrine (1:1000), 0.1 to 0.3 mL given subcutaneously every 15 minutes up to 1 mL total, should be
administered immediately. Additional agents include diphenhydramine (50 mg intravenously) and cimetidine (300 mg
by mouth).
25. Describe the immediate options for management of bronchospasm.
The patient should be monitored closely, and oxygen should be administered by nasal cannula or facemask. In severe
cases, intubation may be required. Pharmacologic treatment includes epinephrine (1:1000), 0.1 to 0.3 mL given
216 PATIENT SEDATION AND PAIN MANAGEMENT
subcutaneously every 15 minutes up to 1 mL total, and aminophylline (4 to 6 mg/kg intravenous loading dose, then
25 mg/min continuous infusion). These agents may be supplemented with inhaled albuterol or metaproterenol.
26. What are possible options for the management of generalized urticaria?
A patient with generalized urticaria can be treated with either diphenhydramine (50 mg intravenously) or cimetidine
(300 mg by mouth). Vital signs should be obtained, and the patient should be observed to ensure that a more severe
reaction is not evolving. The reaction should be documented in the patient s medical record.
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BIBLIOGRAPHY
[1] Ray CE, Turner JH, Cothren CG, Moore EE, Smith W, Scatorchia G, et al., Do CT emergency CT scans add value in hemodynamically
unstable patients undergoing pelvic embolization?, 2004 Society of Interventional Radiology, 29th Annual Scientific Meeting, Phoenix
Arizona.
[2] M. Wojtowycz, Handbook of Interventional Radiology and Angiography, second ed., St. Louis, Mosby, 1995.