Download Lecture 4: Electrophysiology Lab

Anesthesia in
Electrophysiology
Copyright © 2015 Mark S Weiss
All Rights Reserved
The role of anesthesia in the EP lab
• EP labs were originally developed for diagnostic procedures
• EP lab are now used primarily for therapeutic procedures – treatment of
tachyarrhythmias and device implantation
• Procedures becoming more complex with a sicker & less stable population
• Anesthesiologists used to cover ~20% of cases, but now staff 98%
• Like it or not NORA is the wave of the future-> it is the fastest growing
segment of anesthesia care
Copyright © 2015 Mark S Weiss
All Rights Reserved
EP Lab – Lay of the Land
• Anesthesia personnel provide care in both the recovery room and EP Labs
• Unfamiliar territory -> arrive early to ensure time for fundamental safety checks
• Cases may not be as “complex” in terms of fluid shifts or blood loss, but emphasis
must be paid to ensure identical standards to OR CARE
• As in all NORA cases:
• Equipment check (MSMAIDS)
• Machine, Suction, Monitors, Airway, IV meds,
“Special” (jet ventilator, cerebral oximetry)
• Ensure availability and delivery of supplemental O2
Copyright © 2015 Mark S Weiss
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EP Lab – Location Challenges
• Unlike any other anesthetizing location in the hospital, due to
the impressive but intrusive amount of equipment
• Space is designed for the often complex work of the
cardiologists with anesthesia as an afterthought – lab space
often retrofitted with anesthesia equipment
• Moving anesthesia equipment during different parts of a case is
often necessary to accommodate the procedure
• Intubation is performed straddling the lower arm of the x-ray
equipment, ducking under the upper arm, and squeezed by the
two side arms
Copyright © 2015 Mark S Weiss
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EP Lab - Layout
• Typically each EP procedure room has a “control room” where an
electrophysiologist can monitor advanced imaging, mapping and ablation
activities without having to be “hands on”
• During a case, personnel should only enter through the control room
• Headphone walkie talkies can be used to optimize team communication due
to increased noise level, obstructed vision between team members and dim
lighting
Copyright © 2015 Mark S Weiss
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EP Anesthetic Expectations
• VT and AF ablation are typically performed with general anesthesia for
patient comfort
• Anesthetic method best studied in the AF population
• 257 AF pts for RFA: GA higher success rate, reduced PV reconnection, shorter
fluoroscopy time - Di Biase, et al. Heart Rhythm. 2011; 8: 368.
• Most other procedures can be done with minimal to moderate sedation
• Generally, prefer minimal sedation when trying to induce SVT or for PVC
mapping
Copyright © 2015 Mark S Weiss
All Rights Reserved
Pre-Op Evaluation Focus Points
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Airway - identify challenges which may be amplified in NORA environment
Previous anesthetics - review management with focus on sensitivity to sedatives
Allergies - focus on shellfish (contrast dye), fish (protamine), antibiotics
Cardiac Hx - note EF, CHF (ability to tolerate supine position), arrhythmia classification,
pulmonary HTN (avoid hypercapnia/hypoxemia)
• OSA/morbid obesity - important if sedation planned
• Positioning - peripheral neuropathy, back pain- peripheral extremity position/padding
• GERD - important if sedation planned
Copyright © 2015 Mark S Weiss
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EP Cases and Locations
• EP Cases outside the EP lab
• Cardioversions
• TEE
• Non-Invasive Programmed
Stimulation (NIPS)
• Defribillator Threshold
Testing (DFT)
Copyright © 2015 Mark S Weiss
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• EP Cases in EP lab
• Arrhythmia device
placement
• Radiofrequency Ablation (RFA)
• Lead extraction cases (if placed
<1 year)
Anesthetic approach for cases
outside the EP lab
• Cardioversions (~ 15 minutes)
• Short period of deep sedation/general anesthesia, usually using bolus dose of
propofol/etomidate depending on ejection fraction
• A soft bite block should be placed
• Transesophageal Echocardiograms (~ 60 minutes)
• More prolonged sedation may be required in some TEE patients who are unable to tolerate
the procedure with the usual non-anesthesiology provider
• Blunt gag reflex (can topicalize with Cetacaine spray)
• Keep airway open (chin lift/jaw thrust, soft suction if necessary)
Copyright © 2015 Mark S Weiss
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Anesthetic approach for cases
outside the EP lab (cont’d)
• Non-Invasive Programmed Stimulations (NIPS) (~20 minutes)
• Programmed pacing stimulation is in an attempt to elicit ventricular arrhythmias. This usually occurs 1-2
days post VT ablation. If the ICD functions properly, it will anti-tachycardia pace or shock the patient
out of the arrhythmia. If not, external defibrillation/cardioversion with high joule shocks may be
needed. In either case appropriate sedation/general anesthesia will be required.
• Again, use of a soft bite block can prevent tongue and cheek lacerations
• Defibrillator Threshold Testing (DFT)
• Often, but not always performed at the time of ICD placement within the EPS lab. The
anesthetic approach is similar to that described for NIPS above.
Copyright © 2015 Mark S Weiss
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Anesthetic approach for cases
in the EP lab (cont’d)
• Arrhythmia device placement
• 3 types of device functions: Permanent Pacemaker (PPM) [for symptomatic bradycardia],
Implantable Cardioverter-Defibrillator (ICD) [for tachyarrythmias] and devices capable of
cardiac resynchronization therapy (CRT)
• Types of procedures: placement, generator/battery changes, lead placements, defibrillator
testing (DFT), 1 loop placement in superficial abdominal area, subcutaneous (along the
sternum) placement of AICD with abdominal wall generator placement
• Most cases are performed via a transvenous approach with the generator implanted in
pectoral region
• Cases infrequently performed via an epicardial approach (5%)
Copyright © 2015 Mark S Weiss
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Anesthetic approach for cases
in the EP lab (cont’d)
• Anesthetic approach to arrhythmia device placement (2 to 4 hours)
• Typically MAC cases requiring mild to moderate sedation: fentanyl/midazolam with local or
infusions of propofol/remifentanil
• BiV ICD placements may require GA under certain circumstances (ex. OSA, intolerance of
supine position)
• Antibiotic prophylaxis per guidelines
• Occasionally patient’s require a conversion to GA EMERGENTLY (prepare ahead of time)
• Perforation of heart with tamponade is an infrequent but known risk, so be prepared for
volume expansion and vasoactive medication resuscitation
Copyright © 2015 Mark S Weiss
All Rights Reserved
Anesthetic approach for cases
in the EP lab (cont’d)
• Radio Frequency Ablation
• Can identify mechanisms of tachyarrythmias and map out arryhthmogenic foci (anatomically and in
relationship to EKG) with subsequent catheter-directed ablation via radiofrequency energy
• 3 Broad Procedural Categories
• Supraventricular Tachycardia (SVT), Atrial Flutter,
WPW
• Atrial Fibrillation
• Ventricular Tachycardia (Vtach), Premature
Ventricular Contraction (PVC), ventricular nodal
re-entrant tachycardia
• Cases may have epicardial approach
Copyright © 2015 Mark S Weiss
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Scar-related, reentrant
monomorphic ventricular tachycardia
Healthy
Myocardium
QRS
Myocardial
Scar from
Infarction
Copyright © 2015 Mark S Weiss
All Rights Reserved
Photo courtesy of Dr. William Stevenson
Anesthetic approach for cases
in the EP lab (cont’d)
• Anesthetic approach to RFA procedures
• Wide variety in length, complexity and critical nature of arrhythmia-> must discuss with
proceduralist
• Surface defibrillator/pacing pace should be applied in all cases with functioning debrillator
BE PREPARED TO CONVERT TO
GENERAL
ANESTEHSIA
EMERGENTLY
• Some arrhythmias
are frequently
medication/sedation-sensitive
and the proceduralist may wish
available
to give NO sedation at the beginning or throughout the case
• Use solely remifentanil infusion in these cases
• LV assist devices (ex. Impela) may be placed during the procedure for patients with low EF or
severe VT
• If used, cerebral oximetry should be employed
Copyright © 2015 Mark S Weiss
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Common anesthetic approaches to
specific RFA procedures
• Supraventricular Tachycardia (SVT), Atrial Flutter, WPW (2-4 hours)
•
MAC- mild- moderate sedation, need sedation bolus for local femoral access and if Foley catheter placed
• Atrial Fibrillation (6-10 hours)
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General Anesthesia with an ETT and jet ventilation, radial arterial line
• Vtach, PVC (6-10 hours)
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Most complex- start with MAC (mild-mod sedation) during the mapping phase . Assess mental status during Vtach to
determine need to cardiovert/treat hypotension
• Patient factors may preclude MAC (anxiety, obesity). Use cerebral oximetry to determine need to treat hypotension
Copyright © 2015 Mark S Weiss
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•
Femoral arterial access (may not need radial Aline), if patient unstable at end of case, may need rad Aline for post-op care
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GA with ETT during RFA ablation or epicardial approach
RFA complications
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Vascular (hematoma, bleeding, vascular injury) - most common
Cardiac tamponade, perforation
Complete heart block
Line insertion related (air embolism, pneumothorax)
Airway trauma/ hematoma
• Traumatic intubation followed by heparinzation
• Nerve palsy as a result of improper positioning
Copyright © 2015 Mark S Weiss
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RFA complications (cont’d)
• Esophageal Stricture/Perforation
• Risk reduction: Esophageal temperature probe is positioned directly behind the
atrium with fluoroscopic guidance and temperature closely monitored particularly
during ablation
• Phrenic Nerve Injury
• The electrophysiologist can avoid harming the phrenic nerve by identifying its location
with pacing and observing where the pacing causes the diaphragm to move  avoid
muscle relaxants
Copyright © 2015 Mark S Weiss
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Common anesthetic approaches to
specific RFA procedures
• Lead Extraction +/- laser (3-6 hours)
• Usually performed due to system infection, lead malfunction (fracture/failure/erosion)
• Leads older than 1 year may lead to adhesions and removal risks cardiac or vascular avulsion
or other injuries. This is typically performed in main ORs
• ALL require GA with ETT using intravenous or Inhalational agents.
• Blood should be IMMEDIATELY available and cardiac surgical back-up should have
been arranged by the EPS staff.
• Rapid Infuser available
Copyright © 2015 Mark S Weiss
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Airway Management
• Intubations performed with glidescope to decrease
change of airway trauma
• Heparinzation during the procedure may lead to airway
bleeding -> impacts extubation
• MAC cases: must be prepared for EMERGENT
intubation (with glidescope)
• Have nasal airways easily accessible
• Induction technique: if EF <40% consider using
etomidate (or etomidate + propofol)
Copyright © 2015 Mark S Weiss
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High Frequency Jet Ventilation
• Used to minimize respiratory movement during AF ablation
• Decreases atrial motion, promotes intra-cardiac instrument stability
• Should be a joint decision with
proceduralist in advance
• Requires GA with ETT and TIVA
Copyright © 2015 Mark S Weiss
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Anesthetic Drug Choices
• The electrophysiologist may have preferences in regard to avoiding certain
anesthetics, as some agents may suppress an arrhythmia. It is important to discuss
with proceduralist at the start of each case.
• Very light anesthetic is desirable when trying to elicit a premature ventricular
contraction or ventricular tachycardia in order to determine the focus from which
the arrhythmia is arising.
• Consider using only remifentanil and no midazolam
• In most general anesthesia cases, inhalational agents should be avoided because of
anti-arrhythmic effects
• AVOID long-acting muscle relaxation to help monitor phrenic nerve activity
Copyright © 2015 Mark S Weiss
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Patient Positioning
• An arterial line should be placed on the opposite side from which the
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electrophysiologists operate in case adjustment is needed
A soft bite block should be placed for possible
cardioversions/defibrillations
Double check proper position of extremities as arms are typically tucked at
sides
• See positioning figure: pillow under knees, roll under neck
Patients are not paralyzed. With cardioversion/defibrillation, there can be
significant muscular contracture  wrists must be restrained and
extremities padded
Access to the stopcocks, IV lines and monitors will be limited once the
patient is draped
Copyright © 2015 Mark S Weiss
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Shared Drug Administration
• Oftentimes, Cardiology nurses may be assigned to administer various
medications
• Heparin, vasoactive inotropes
• Cardiologists may administer drugs directly into cardiac catheters
• Nitrogylcerine, Calcium Channel Blockers
• Hemodynamically acting meds and anesthetics may interact with procedure
• COMMUNICATON IS PARAMOUNT
Copyright © 2015 Mark S Weiss
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ISUPREL Challenge
• One of the most difficult times in managing hemodynamics is when the electrophysiologist
wishes to evaluate the induction of an arrhythmia using increasing doses of Isuprel.
• Normally Isuprel is started at 3 mcg/min by the EPS lab nurses and titrated to 6, 12, 20, 30 mcg/min,
although the dosing is variable.
• This typically produces a significant loss of peripheral resistance and drop in blood pressure
• The anesthesiologist will likely need to start phenylephrine to support a SBP 130-140
• Along with the drop in blood pressure, the heart rate will increase to uncomfortably high levels
and occasionally ventricular tachycardia or fibrillation will ensue.
• The electrophysiologists are able to treat arrhythmias
• Preventing the severe rebound hypertension that occurs once the Isuprel is discontinued is a
challenge. Phenylephrine should be turned off immediately when the Isuprel is discontinued
Copyright © 2015 Mark S Weiss
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Hemodynamic Management
• Patients may become part extremely labile hemodynamically.
• Reactions to these drastic changes at times needs to be tempered (look for underlying cause of vital sign
instability) as well as determine when rapid intervention is needed
• Electrophysiologists are very involved in the patient’s hemodynamic management
• When needed, theu can control the heart rate with pacing or cardioversion
• Communication is critical, particularly when making significant changes to the level of anesthesia
• Hypotension may be caused by tamponade or retroperitoneal bleeding and masking these
changes with medication can delay a timely diagnosis.
• In the routine case, the patient will receive a large amount of volume by the electrophysiologist
during the ablation process, so fluid management by anesthesia should be conservative
Copyright © 2015 Mark S Weiss
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Post- Op Management
• Pain generators
• Back pain/Extremity pain for laying supine for prolonged period
• Foley catheter
• Intravascular Catheters in groin, need to hold pressure
• Typical Pain medications:
• KETOROLAC typically given (avoid in renal impairment)
• Morphine/Dilaudid to be considered
• Ondansetron for PONV
Copyright © 2015 Mark S Weiss
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TIPS for Success
• Communication
• Understanding procedures and their effects on hemodynamics as much as
possible
• Preparation and ensuring proper positioning, line set up
• Comfort in a NORA setting
Copyright © 2015 Mark S Weiss
All Rights Reserved