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Chapter 11
Safety in the Periprocedural Period
Stan Zipser
The possibility of adverse outcomes during or following embolization procedures
is an unfortunate reality of the type of work that is performed in interventional
radiology suites. Certain criteria may be followed, however, to help reduce the likelihood of such adverse outcomes. Some detrimental outcomes are due to technical
factors, such as non-target embolization or ischemia caused by embolization procedures. Other harmful outcomes occur as a result of the medications and contrast
agents used routinely during embolization procedures. This chapter focuses on the
safe administration of medications routinely used for sedation and analgesia, as well
as the intravascular administration of contrast media.
Introduction
• Many procedures can be performed without analgesia or sedation. The risks associated with such medication administrations must be taken into account with the
benefits derived by their use.
• Adequate sedation and analgesia are typically necessary for patient satisfaction
in anxious patients, and during any painful embolization procedure.
• Optimal patient care requires the following:
◦ Anticipation that a procedure may require analgesia and sedation.
◦ Awareness of factors that increase procedural risk.
◦ Familiarity with analgesic and sedative drugs, and agents used for their
reversal.
◦ Organization of appropriate regimens for sedation and analgesia before,
during, and after the procedure.
◦ Appropriate patient monitoring during and after the procedure.
◦ Alertness to and knowledge of potential complications.
• It is a devastating outcome to perform a “successful procedure” technically
only to have the patient suffer consequences from unsafe practices regarding the
administration of sedation, analgesia, or contrast media!
Transcatheter Embolization and Therapy,
Techniques in Interventional Radiology, DOI 10.1007/978-1-84800-897-7_11,
C
Springer-Verlag London Limited 2010
111
112 S. Zipser
Pre-procedural, Procedural, and Post-procedural
Considerations
First and foremost, know your patient.
• The patient’s history should be taken evaluating key factors (Table 11.1).
• A physical examination should also be performed, focusing on cardiopulmonary
and airway status.
Table 11.1 Key factors in pre-sedation patient assessment
• Abnormalities of major organ systems
• Previous adverse experience with sedation and analgesia and general anesthesia
• Drug allergies
• Current medications
• Potential drug interactions
• Time and type of last oral intake
• History of tobacco, alcohol, or substance use
The American Society of Anesthesiologists Task Force on Sedation and
Analgesia by Non-anesthesiologists has made recommendations that include the
following:
Pre-procedure
• A patient’s informed consent to administer sedation/analgesia should be obtained.
• Patients should be fasted before a procedure. Guidelines suggest clear liquids no
later than 2 h and a light meal no later than 6 h before the procedure. In case of
an emergency procedure, consider altering the target level of sedation/analgesia
or consider pre-procedural endotracheal intubation to protect the airway against
aspiration.
Procedural
• The practitioners responsible for the patient receiving sedation should understand
the pharmacology of any drugs they use, their risks, and the role of reversal
agents.
• A designated individual, other than the person performing the procedure, should
monitor the patient at all times.
• At least one person capable of establishing a patent airway and positive pressure
ventilation should be present.
• An ACLS-certified person should be readily available.
• Emergency equipment should be available.
11 Safety in the Periprocedural Period 113
• Patient’s response to verbal commands and tactile stimulation should be
monitored.
• The patient’s oxygen saturation and blood pressure should be monitored in all
patients, and oxygen administered if the pulse oximeter oxygen saturation falls
below 96% (indicating arterial hypoxia).
• The blood pressure should be obtained before, during (at 5 min intervals), and
after the procedure.
• Electrocardiographic activity should be monitored for patients in deep sedation.
• Medications should be given incrementally with sufficient time between doses to
assess effects.
Post-procedural
• Patients should not be allowed to drive until the effects of sedatives have worn off.
• Patients should not be discharged from the post-procedure area until baseline
vital signs are achieved.
Safe Sedation and Analgesia During the Procedure
• The guidelines given above should be adhered to as closely as possible.
• Most embolization procedures are performed under moderate (conscious) seda-
tion with intravenous medication, with a nurse monitoring the patient.
• Moderate (conscious) sedation/analgesia is defined by the American Society
of Anesthesiologists as “...a drug induced depression of consciousness during
which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a
patent airway, and spontaneous ventilation is adequate. Cardiovascular function
is usually maintained.”
• If a procedure requires deeper sedation than this, then anesthetist assistance
should be requested. This is the case with very painful procedures, confused or
agitated patients, and patients those who cannot keep still.
• In patients presenting with hemodynamic instability, it is wise to caution on the
side of undersedation rather than oversedation. Although the procedure may be
uncomfortable, the risk of administering medications with severe side effects may
outweigh the benefits of temporary discomfort during the procedure.
• Certain patient populations (e.g., hemodynamically unstable, the very young or
the very old) require increased attention during and following the procedure.
Staff
• Local protocols should be in place.
• According to the American Society of Anesthesiologists, as well as the Joint
Commission for the Accreditation of Hospital Organizations, a person other than
114 S. Zipser
the operator must be responsible for the administration of the sedation and analgesia medications, as well as for monitoring the patient following administration
of the medications.
• At least one individual should be capable of establishing an airway.
• At least one individual should be advanced cardiac life support (ACLS) trained.
• If pediatric patients are being sedated, it is strongly encouraged to have at least
one pediatric advanced life support (PALS) certified individual in the procedure
room.
• Nurses should be appropriately trained in mixing and administering medications
used in sedation and analgesia, as well as medications used in the treatment of
complications such as hypotension, hypoxia, and dysrhythmias.
Equipment
It is vital to have all appropriately sized equipment readily available. This includes
the following:
Routine Care Equipment
• Hemodynamic monitoring equipment
• Equipment for monitoring ventilation
◦ Pulse oximetry and/or
◦ Carbon dioxide monitor
• Oxygen supply, masks, and nasal cannulae
Emergency Equipment
◦ Make sure you and your staff know where everything is and how to use it!
◦ IV fluids
• Standard and pediatric size intubation trays
• External defibrillators
• Temporary pacemakers
• External pacing/defibrillation pads
• Pacing wires/catheters
Medications
• The ideal medications have a rapid onset of action, short half life, are reversible,
and are effective in achieving their purpose.
• Since most medications used during embolization procedures have short half
lives, they can be easily titrated to effect.
11 Safety in the Periprocedural Period 115
• If sedation and analgesia are being provided, then reversal agents should be
readily available.
• Supportive medications, such as medications to treat hypertensive episodes (beta
blockers, alpha blockers, calcium channel blockers) and hypotensive episodes
(levophed, dopamine) should be readily available.
• Commonly used medications in moderate sedation and analgesia are presented in
Table 11.2.
Table 11.2 Commonly used medications for sedation and analgesia
Drug Dose (IV) Onset Duration Comments
Hypnotics
Midazolam (versed) 0.5–1 mg 1–3 min 45–60 min Can cause respiratory
Lorazepam (ativan) 1 mg 5–10 min
Diphenhydramine
(benadryl)
Analgesics
Morphine sulphate 2–5 mg 5–10 min 4–6 h
Fentanyl (sublimaze) 25–50 μg 2–5 min 45–90 min Respiratory depression
Toradol 15–30 mg 5–10 min 6–8 h Parenteral NSAID often
Reversal agents
Naloxone (narcan) 0.1–0.3 mg
Flumazenil (romazicon) 0.2 mg
Anti-nausea
Odansetron (zofran) 4 mg 30 min 4–6 h 32 mg daily dose limit;
25–50 mg 10–20 min 4–6 h Also has anti-nausea
2 min 30–45 min Opioid reversal agent
q30–60 s
1–2 min 10–30 min Benzodiazepine reversal
q1–2 min
depression especially
in COPD patients
effects
occurs at 5–15 min
used in UFE
agent; 3 mg total dose
8 mg in patients with
severe hepatic
cirrhosis
Complications
• Commonly encountered situations (e.g., hypotension) should be anticipated and
algorithms created for sufficient treatment (Fig. 11.1).
• A spectrum of antibiotics, particularly those that treat gram-negative organisms
(due to the potential for severe and rapid sepsis), should be available. These
agents include third-generation cephalosporins, gentamycin, and levoquin.
• It may be helpful to have such algorithms for common problems posted in the
procedure rooms.
116 S. Zipser
Fig. 11.1 Evaluation and treatment of hypotension
Anesthesiology Assistance During Sedation and the Use of General Anesthesia
Do Not Hesitate to Ask for Anesthesia Assistance!
Common indications for consultation with an anesthetist for monitored anesthesia
care or general anesthesia during embolization procedures include the following:
• Hemodynamic instability, often due to trauma or from gastrointestinal or other
bleeding source.
11 Safety in the Periprocedural Period 117
• Airway protection (intubation) during bronchial artery embolizations or any other
procedure where there is potential respiratory compromise.
• Patient comorbidity causing possible loss of airway patency.
• Confused, agitated, or demented patient.
• Low pain threshold or inability to remain still, particularly in patients who are
unable to be adequately controlled with moderate sedation.
• Neurointerventional procedures, such as AVM embolization.
• Embolization procedures in pediatric patients.
• Peripheral AVM embolization.
Safe Sedation and Analgesia Following the Procedure
• Post-procedural pain control is vital for both patient’s safety and satisfaction.
• Post-procedural sedation is not typically needed unless pain management cannot
be accomplished using standard analgesia regimens.
• If sedation and analgesia are used in combination in the post-procedural period,
then it is vital to be aware of the increased likelihood of hemodynamic or
ventilatory compromise.
• Analgesia is typically administered through the use of opiods.
◦ Different opiods have different strengths, onsets of action, and duration of
action. Depending on these variables, medications can be tailored to fit the
patient needs.
◦ It is important to evaluate the availability of nursing staff and/or medications
if analgesia is ordered on an as-needed basis. If nurses will not be readily
available, routine dosing of medications (e.g., morphine sulfate, 4 mg IV every
4 h) may result in a more predictable dose to the patient.
• Patient-controlled analgesia (PCA) pumps are frequently very helpful in the
embolization patient population. Orders for these units are typically tailored for
each patient. If opiods are used for a PCA pump, it is recommended to also write
for as-needed orders for nausea that may result from the opiod administration.
Typical PCA orders include a loading dose (a one-time dose the patient is given at
the start of the PCA pump administration), basal rate (aliquot of medication given
automatically, with the patient requesting it), a demand dose (the dose given each
time the patient requests a dose), and a lockout period (the minimum amount of
time between demand doses). Table 11.3 gives examples of typical PCA pump
orders given following embolization procedures.
Table 11.3 Examples of patient-controlled analgesia orders administered in the post-procedural
period
Medication Loading dose Basal rate Demand dose Lockout period
Fentanyl 10–50 μg 0–10 μg 5–20 μg 6–10 min
Hydrocodone 0.2–1.0 mg 0.2–0.4 mg 02.–0.4 mg 6–10 min
Morphine 0.2–1.0 mg 02.–0.4 mg 0.2–0.4 mg 6–10 min
118 S. Zipser
Safe Administration of Contrast Media
Contrast-Induced Nephropathy
• Contrast-induced nephropathy (CIN) is often defined as an increase in serum
creatinine by greater than 25%, or an absolute increase of >0.5 mg/dl, within
3 days of contrast administration.
• Most frequently, CIN is characterized by serum creatinine levels beginning to
rise within 24 h, peaking within 96 h, and returning to normal within 7–10 days.
However, temporary or permanent dialysis-dependent renal failure can result.
• There is a very low to no risk of CIN in patients with normal renal function.
Risk increases as baseline renal function decreases—the worse the function, the
greater the risk.
• The nephrotoxic effect of contrast is dose dependent: the higher the administered
dose of contrast, the higher the risk of CIN.
• Risk factors for the development of CIN include the following:
◦ Diabetes Mellituas
◦ Dehydration
◦ Concurrent use of furosemide with the contrast administration
◦ Patients with multiple myeloma
◦ Hypertension
◦ Age > 70 years
◦ Congestive heart failure
◦ Hyperuricemia
◦ Patients taking nephrotoxic medications (including NSAIDS)
Prevention of CIN
• Non-ionic agents have been shown to be less toxic than ionic agents, and
therefore are generally favored over ionic agents.
• The use of low and iso-osmolar agents has been shown to decrease contrast-
induced nephropathy and adverse contrast reactions.
• An IV fluid regimen of 0.9% saline (100 cc/h for 12 h before and after an
angiographic procedure) has been shown to reduce the risk of CIN.
• The benefit of using pre- and periprocedural sodium bicarbonate IV drips and
oral N-acetylcysteine is debatable. Due to the low likelihood of adverse reactions
to both agents, many operators will use these agents even in the absence of firm
data suggesting benefit.
• Patients with known renal dysfunction, or those who are at risk for CIN or who
have significant comorbidities, should suspend metformin use for 48 h after the
administration of iodinated contrast.
• Carbon dioxide gas is a non-toxic, low viscosity, highly soluble gas that acts as
a negative contrast agent. It may be used in embolization procedures for patients
with a contrast allergy or renal insufficiency.
11 Safety in the Periprocedural Period 119
Keypoints
Patient Safety and Comfort Are Paramount
• Published guidelines from the ASA and JCAHO regarding sedation and
analgesia are readily available and should be followed.
• Sedation and analgesia may be necessary in the pre-, peri-, and postprocedural periods. The patient should have the opportunity to be treated
for their pain/anxiety before and after the procedure, not just during the
procedure.
• It is vital to remember what each drug class is used for! Most sedatives
offer little or no analgesic effect. If the procedure is going to hurt, soli-
tary use of sedation will not be adequate! In addition, there is a synergistic
effect between benzodiazipenes and opiods, with each drug class accentuating the effect of the other. In the vast majority of instances, therefore, it
is advantageous to use both medication classes together.
• Certain risk factors place patients at high risk for contrast-induced nephrotoxicity (CIN). Aggressive use of IV fluids is the only proven method to
protect the kidneys from CIN. Certain risk factors are known, but the risk
of NOT performing an embolization procedure should be weighed against
the risk of administering contrast media.
Suggested Readings
1. Kelly AM, Dwamena B, Cronin P, Bernstein SJ, Carlos RC. Meta-analysis: effectiveness of
drugs for preventing contrast-induced nephropathy. Annals of Int Med (2008):148(4):284–294
2. Morcos SK. Prevention of contrast media-induced nephrotoxicity after angiographic procedures. J Vasc Interv Radiol (2005);16:13–23
3. Rao QA, Newhouse JH. Risk of nephropathy after intravenous administration of contrast
material: a critical literature analysis. Radiology (2006); 239:392–7
4. Shabanie A. Conscious sedation for interventional procedures: a practical guide. Tech Vasc
Interv Rad (2006);9:84–8
5. Practice Guidelines for Sedation and Analgesia by Non-Anesthesiologists, Anesthesiology
(2002);96:1004–17
6. Lee, SH, Hahn, ST, Park, SH. Intraarterial lidocaine administration for relief of pain resulting from transarterial chemoembolization of hepatocellular carcinoma: Its effectiveness and
optimal timing of administration, Cardiovasc Intervent Radiol (2001);24:368–371
7. Keyoung, JA, Levy, EB, Roth, ER, et al. Intraarterial lidocaine for pain control after uterine
artery embolization for leiomyomata, J Vasc Interv Radiol. 2001;12:1065–1073
8. Lang EV, Berbaum KS, Pauker SG, et al. Beneficial effects of hypnosis and adverse effects
of empathic attention during percutaneous tumor treatment: when being nice does not suffice.
J Vasc Interv Radiol (2008); 19:897–905
Chapter 12
Complications of Embolotherapy
Lakshmi Ratnam and Robert Morgan
Complications directly attributable to embolization essentially comprise the
following:
• Consequences of non-target embolization
• Sepsis
• Infarction and/or necrosis of embolized tissue
• Extravasation of liquid agents
• Misplaced embolization coils
General complications of angiography related to access s ite and contrast nephro-
toxicity will not be addressed in this chapter.
Prevention, Detection, and Recognition
Prevention: not all complications can be prevented but many can be anticipated and
therefore avoided.
Pre-procedure
• Planning: review the diagnosis, options, and vascular approaches carefully.
• Consent: discuss the procedure and inform the patient of recognized risks.
• Antibiotic prophylaxis: this may be appropriate in solid organ embolization,
especially if a large area of infarction is expected.
• Anatomy: thorough knowledge is the key to success and failure! Presence of
anatomical variants may result in non-target embolization, if the operator is
unaware of the pitfalls.
Transcatheter Embolization and Therapy,
Techniques in Interventional Radiology, DOI 10.1007/978-1-84800-897-7_12,
C
Springer-Verlag London Limited 2010
121