Volume 6, Issue 11 S A M B A T A L K S - PAGE 2 April, 2007

JOIN THE DISCUSSION - TOP

Need advice about a problem case in ambulatory anesthesia? Suggestions about a difficult situation in your ambulatory surgery center? A reply to questions others have raised about ambulatory anesthesia issues?

If you answered "yes" to any of these questions, or would like to share with other professionals a comment or opinion on a topic related to ambulatory anesthesia then please "Join the Discussion".

Your question, reply or comment will be published in the next available issue of SAMBA TALKS. Include your name (or initials), email address, city, and state, if you would like these published. Please note that because of the high volume of questions we receive, there is often a delay of 1 to 2 months before publication.

SAMBA Talks will include all discussion questions we receive considered of interest to the membership at large. We will endeavor to publish a response to at least one of these questions. The response will be from experts in the field, and from those willing to express a view on a particular topic, backed by experience and/or published evidence. Where email addresses are published, those individuals have indicated their interest in discussing the published questions.

Questions and responses from previous months are now available at the eNewsletter Discussion Archive. If you have any comments regarding the previous questions, please submit them to SAMBA Discussion, and they will be published here next month.

Please note: The information presented in the replies below does not represent SAMBA policy. The replies are solely the opinions of the individuals who wrote them.

?? - LAST MONTH'S QUESTION WITH REPLIES - ?? - TOP

Question

I would like to hear opinion regarding patients with AICDs having surgery at an ambulatory surgery center.  The question pertains to cataract surgery as well as other surgical procedures performed at the center.  We have one Ophthalmologist who uses retro bulbar blocks which requires sedation levels that currently meet the general anesthesia definition.  According to current guidelines set forth by ASA and the American College of Cardiologist, all AICDs need to be interrogated following surgery prior to removing the patient from continuous cardiac monitoring.  The manufacturing representatives tell me that this is not necessary with their new devices. When I ask them to give me written documentation from their companies stating post op interrogation is not necessary their companies won't put this in writing.  When a Cardiologist writes in his note that a patient has an AICD because they are a constant threat for sudden cardiac death I find it hard to allow that patient to undergo a procedure at an ambulatory center, even if it is a cataract that requires "general anesthesia" for placement of a retro bulbar block.

-- From: Gary Thompson, MD, Beaufort, SC (anesmd@bmhsc.org)

Reply 1

The most effective treatment for sudden cardiac death caused by VF is internal defibrillation by an implanted AICD.

The potential sources for electromagnetic interference (EMI) to a cardiac rhythm management device (CRMD: which refers to any permanently implanted pacemaker or ICD) are:

1. Unipolar electrocautery
2. Radiofrequency ablation
3. Lithotripsy
4. MRI
5. Radiation therapy.

Bipolar electrocautery or ultrasonic (harmonic) scalpels are safe.

In your case, if the surgeon is not using a device that generates EMI (as listed above) then there is no need to have the ICD turned off. The depth of sedation does not matter.

However, in the ophthalmology operating rooms, we do need to be aware of the risk of eye injury from patient movement in the event an ICD discharges appropriately; we must monitor the electrocardiogram vigilantly. If a ventricular arrhythmia occurs in a patient with a functioning ICD, we would expect to have about 15 seconds from the time the arrhythmia starts until a shock is delivered to the patient. Hopefully, this would be enough time to warn the surgeon to adjust or remove the intraocular instruments and prepare for possible movement.

The statement from the ASA that “all AICDs need to be interrogated following surgery prior to removing the patient from continuous cardiac monitoring” refers to situations when the AICD is turned off.

-- From: Jia Lin, MD, Cleveland, OH

Reply 2

This appears to be a multipart question and the answer is complicated.  For the record:  I am an anesthesiologist with a special interest in pacing and defibrillation.  I have passed the North American Society of Pacing and Electrophysiology (NASPE) exam, a cognitive instrument designed to test knowledge in this field.  I run a pacemaker and ICD follow-up clinic at my hospital, and I have performed more than 2,000 pacemaker and ICD follow-up evaluations over the past 7+ years.  Please understand that this is a general discussion, not specific recommendations for any patient or situation.

First, patients get ICDs (AICD is a brand name, owned by Guidant) for:  history of sudden cardiac arrest, inducible ventricular tachycardia, or cardiomyopathy (etiology is now irrelevant) with left ventricular ejection fraction < 35%.  As a result, there are plenty of patients with an ICD that has never delivered antitachycardia therapy.

Second, only the American College of Cardiology has “guidelines.”1  These guidelines do indeed recommend a preoperative comprehensive evaluation of a cardiac generator (be it a pacemaker or a defibrillator).  The ASA has published an “advisory,” which consists of a literature review and expert opinion stating that a timely, preoperative interrogation of cardiac generators is warranted2.

Third, the manufacturer’s representatives do not make policy for the manufacturers and are basically, rendering their own opinion. Even though the manufacturer’s representatives are very helpful few are licensed medical practitioners and hence, not in a good position to render medical advice.  

Fourth, for the most part, manufacturers recommend a follow-up ICD evaluation not to exceed 4 months. This recommendation is in a state of flux due to a variety of reasons including the need to evaluate older pacemakers on a more frequent basis and the ability to evaluate abnormalities from newer devices via a phone check. Data from my institution suggests that about a third of pacemaker patients have not been evaluated with a programmer for more than a year and more than 4% arrive at their first visit with a pacemaker in need of replacement for battery depletion.

Fifth, there are ICD patients who receive antitachycardia pacing (ATP) but no shock. Since ATP is very well tolerated many patients are unaware that this is happening.  This information is important and may only be revealed with an interrogation.

Sixth, there are a number of ICDs, and pacemakers on alert for a variety of issues, some of which are premature (and undetectable) battery failure.  So if a patient has an underlying sinus rhythm with normal AV nodal conduction at 70 bpm, then the surface EKG will likely show (appropriately) no pacing. 

Seventh, there are magnet issues.  Medtronic ICDs always respond to appropriate magnet placement by turning off the tachy-therapy section, but there is no feedback.  St. Jude ICDs can be programmed to ignore a magnet, and there is no feedback.  Guidant ICDs can be programmed to ignore a magnet (in fact, there are 45,000 Guidant ICDs with a magnet switch problem wherein the “fix” is to disable magnet detection).  When magnet mode is enabled in a Guidant ICD, it will beep with each R wave (use the stethoscope bell over the hole in the magnet) indicating that tachy therapy is disabled.  However, some of these ICDs are programmed to completely turn off the tachy therapy after 30 seconds of magnet placement, so simple magnet removal will not restore tachy therapy.  In this case, the ICD will be emitting a constant tone, and re-application of the magnet for an additional 30 s should restore the R wave beep, and then removal of the magnet restores tachy detection and therapy.  So one might need to carefully re-think the decision to routinely apply a magnet to an ICD.

Finally, there is plenty of misinformation about pacemakers and ICDs, even published in journals.  Until very recently, there was no training requirement in the cardiology curriculum specifically addressing permanent pacemakers or ICDs.

So what should be done?  What is reasonable?

I believe that every facility should have a policy, and that policy should be followed.  The policy should spell out who needs a preoperative interrogation or a note from their implanting physician (everybody, I believe).  This is a very small burden on the surgeon, not different from an internal medicine evaluation for diabetes, hypertension or coronary artery disease, and it might save a life or two.  The question of magnet placement should be addressed – for example, for an eye case with no monopolar Bovie (the statement “no monopolar Bovie” means that absolutely NO current return pad gets placed on the patient at any time), I believe that the ICD need not have antitachycardia therapy disabled with programming unless a lead alert is present.  Also, consider that magnet placement on the appropriate ICD can provide an extra margin of safety for a failing ventricular lead.  I said this at the Ophthalmology Anesthesia Conference in Chicago last October.  But this subject could be addressed in the consult letter to the EP physician, which should state the proposed surgery, whether or not monopolar Bovie will be used, and the expected length of the procedure.  The consult note should ask when the last antitachycardia therapy was delivered, whether a magnet placement on the ICD will actually work, and what is the underlying rhythm of the patient.  The consult request should ask how much longer the battery will last – more than 6 months should be present for any pacing dependent patient where monopolar Bovie is likely to be used.  It should ask about the last capacitor charge time – more than 12 -15 seconds is a red flag.  The consult request should ask for guidance for the patient who will need monopolar Bovie, and the patient position, if not supine, might make a difference.  The consult request should also ask whether or not a follow-up ICD (or pacemaker) exam will be needed prior to discharge of the patient, and, if one is needed, who will be the supervising physician for the representative.  The facility policy should address whether a complicated patient is eligible for care at the facility (I believe that someone who is having regular and recurrent ventricular arrhythmias is not a candidate for an outpatient surgicenter unless an arrhythmia expert is present).  The destination / back up hospital should be a part of this as well.  After all, how can they provide backup if they have no electrophysiology service?  Generally, I would err on the side of caution. 

Finally, I would encourage SAMBA members to get involved in caring for pacemaker and ICD patients.  There are currently two US anesthesiologists with NASPExam testamur status.  It is very clear that more pacemakers and ICDs are going to be implanted (current estimates suggest that more than 550,000 new cases of cardiomyopathy occur in the US yearly), and we are going to have to take care of them.  Learning to check a pacemaker or ICD and quickly deciding who is likely to be high risk is, in my opinion, easier than learning to do echocardiography.  For the physician who wants to learn more ask one of your manufacturer’s representatives to take you along on a “follow-up day.”

1. Eagle KA, Berger PB, Caulkins H et al. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery. Published January, 2002. Available at: http://www.acc.org/qualityandscience/clinical/guidelines/perio/clean/pdf/perio_pdf.pdf Accessed January 1, 2007.
2. Practice advisory for the perioperative management of patients with cardiac rhythm management devices: pacemakers and implantable cardioverter-defibrillators: a report by the American Society of Anesthesiologists Task Force on Perioperative Management of Patients with Cardiac Rhythm Management Devices. Anesthesiology 2005; 103(1):186-98.

-- From: Marc Rozner, PhD, MD, Houston, TX

?? -- THIS MONTH'S QUESTIONS -- ?? - TOP

Question 1

I work at a freestanding multispecialty surgicenter. We do a lot of extensive liposuction procedures. Are there any guidelines about doing liposuctions at ASCs regarding the amount of fat that can be safely removed and fluid replacement?

-- From: Niraja Rajan MD FAAP, Hershey, PA   (hmcphys@HOSC.biz)

Question 2 and 3

I head a free standing surgicenter (10 OR) in Massachusetts and wanted some information on duration of physician coverage: When can the anesthesiologist leave the surgicenter? Are they required to stay until the patients are physically out of the building or can we go when they move from Phase-1 to Phase-2?
Your advice is highly appreciated.

-- From: Vijayendra Sudheendr, MD Rhode Island (vsudheendr@cox.net)

I am the Director of Nursing at a free standing ambulatory surgery center in California. I am concerned about not having a physician in our facility while patients are still there. The current anesthesia group does not see the necessity of staying. In the past an anesthesiologist was present until the last patient was discharged home, a system that my staff and I were very comfortable with. Does your organization have a position on this? Thanks

-- From: Mena Reese, RN, San Francisco,CA (mena.brady@healthsouth.com)

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