Volume 4, Issue 4 S A M B A T A L K S - PAGE 1 September, 2004

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Do you have a problem case or situation in ambulatory anesthesia about which you would like some advice? Would you like to reply to questions others have raised about ambulatory anesthesia issues? Do you have any comments or opinions regarding any topic related to ambulatory anesthesia which you would like to share with other professionals? If you answered "yes" to any of the above, then "Join the Discussion" here.

To enter the Discussion with a question, reply, or other comment, please contact us. Your question/reply/comment will be published in this section of the next available issue of SAMBA TALKS. Include your name (or initials), 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 the questions can be published.

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

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

QUESTION 1:

I am the medical director of Canyon Surgery Center in Phoenix, AZ.  During a recent State inspection we were told that a death had occurred in a patient with a stent in a local outpatient facility. They felt that we needed to formulate a policy for when patients post insertion of a coronary stent are candidates for outpatient surgery.  I have been searching the cardiology literature only to find that the cardiologist do not agree with any specific time recommendation.  Their literature says anything from ok to do in first 2 weeks after insertion of stent, but not ok after 8 weeks, to should wait 4-6 weeks for anticoagulant therapy, and one paper noted a 30% restenosis rate within the first 6 months. 

I have asked several other medical directors in my area and we have all come up against the same problem of no real answer in the literature. I even contacted the American College of Cardiology who referred me to an article which didn't give a concrete answer either.  In that article they basically took the position that cardiac clearance consists of "optimizing the patient", but didn't give any real guidelines either.  I also contacted the ASA and was given the following response from Karen Williams, M.D., Chair of the Committee on Surgical Anesthesia:

"Your question regarding the timing of performing elective surgery following the recent placement of coronary stents was referred to me as Chair of ASA's Committee on Surgical Anesthesia.  Your question was circulated to committee members who all agree with your research on the matter.  The current literature is controversial regarding the timing of elective surgery after stenting.  There are no prospective, definitive studies.  Empirically, some institutions wait until the antiplatelet therapy is maximized, others wait for 4 weeks up to 12 months for some types of stents if there is a high restenosis rate within the first few months.  It seems that your policy would be based on the multidisciplinary input with your cardiologists, based on your best judgment."

So, I am very interested to see if some sort of consensus can be reached and a standardized time agreed upon.   

-- From Rebecca Dalmeida, M.D., Phoenix, AZ.

REPLY:

Cardiologists have added coronary stents to balloon angioplasty because they prolong patency. However, the downside is an early (~1 st three months) increase in stent thrombosis compared to angioplasty alone. For this reason, cardiologists employ aggressive antiplatelet therapy in the short-term (weeks to months) after stent placement.

Obviously, we would prefer not to anesthetize a patient in the midst of stent thrombosis, or just before, especially since hypercoagulability often follows surgery. On the other hand, surgery performed on a patient receiving aggressive antiplatelet therapy may increase bleeding. In the 2002 revision of AHA/ACC Guidelines for Perioperative Cardiovascular Evaluation For Noncardiac Surgery (Eagle KA et al. Circulation. 2002;105:1257-67), the following was recommended:

“There is uncertainty regarding how much time should pass between PCI (percutaneous coronary intervention) and noncardiac procedures. Delaying surgery for at least 1 week after balloon angioplasty to allow for healing of the vessel injury has theoretical benefits. If a coronary stent is used, a delay of at least 2 weeks and ideally 4 to 6 weeks should occur before noncardiac surgery to allow 4 full weeks of dual antiplatelet therapy and re-endothelialization of the stent to be completed, or nearly so.”

While several studies suggest that most patients who have had a stent do well, others suggest that surgery in the 6 weeks after stent placement may be associated with catastrophic events (Kaluza GL et al. J Am Coll Cardiol. 2000;35:1288-94). These include stent thrombosis if the antiplatelet therapy is stopped, and hemorrhagic complications if therapy is continued. However, this cohort of patients underwent major vascular surgery; the relevance to smaller out-patient procedures in unclear.

My recommendation, acknowledging a rapidly changing field and the absence of clear guidelines, is that elective surgery be postponed until at least 4 weeks of antiplatelet therapy are completed, followed by 1 week off of antiplatelet therapy. In some cases (especially carotid endarterectomy, cerebrovascular disease) cardiologists and/or surgeons may wish to continue therapy until the time of surgery, with the attendant bleeding risks. For patients who have an “old” stent (placed more than 2-3 years in the past), preoperative stress testing and/or cardiology consultation may be warranted if there are significant risk factors, symptoms, or exercise limitation because stents (and certainly angioplasty) are less durable revascularization than CABG.

-- From John E. Ellis, M.D., Chicago, IL

QUESTION 2:

I work in an outpatient unit that is connected by a bridge to a hospital that has no pediatrics or pediatricians.  The local pediatric surgeon has just adopted us to do all of his elective surgical cases.  What is the youngest appropriate age to care for non-premature infants for ambulatory procedures in this setting in order to minimize the risk of peri-anesthetic complications (apnea)?

-- Anonymous

REPLY:

Apnea risk is one of the concerns in ambulatory care of infants, but there is little evidence regarding the risk in healthy term infants.  Selection of the procedure is also important; if pain can be managed with local/regional or non-opioid analgesia postoperatively then there can be greater comfort with doing the procedure on an outpatient basis.  Many facilities will do healthy term infants for relatively minor procedures (hernia repair, circumcision, etc) on an outpatient basis but as a first morning case and with a somewhat longer period of observation in the facility - 4 hours being an arbitrary number often chosen (Everett LL. How young is the youngest infant for outpatient surgery? in Fleisher, L, ed: Evidence-Based Practice of Anesthesiology; Saunders, Philadelphia, 2004; pp. 419-23.)  This also generally does not apply to higher risk populations such as infants with pyloric stenosis.

As the question notes, risk is higher in former premature infants, and has been stratified by Cote (Cote CJ, et al Anesthesiology 1995;82:809-21). Many facilities choose cutoff between 46 and 60 weeks postconceptual ages, or, to simplify, use 6 months post-delivery at any postconceptual age.  Anemia or ongoing apnea may extend the risk.

Other concerns include experience of the anesthesia provider, age-specific competency of the nursing and other support staff, and the availability of appropriate equipment.  Staff should be PALS-trained and there must be a transfer agreement in place with a facility which could accept pediatric patients.  Several studies suggest some increased anesthetic risk in patients under 1 year of age (Morray JP et al. Anesthesiology 2000;93:6-14).  The American Academy of Pediatrics Section on Anesthesiology has developed guidelines for the pediatric perioperative anesthesia environment ( Pediatrics 1999;103:512-5) which have been echoed by the ASA (http://www.asahq.org/clinical/PediatricAnesthesia.pdf) and Society for Pediatric Anesthesia (http://www.pedsanesthesia.org/policyprovision.html).  A basic component of these is the suggestion that each facility delineate what patient ages, populations, and procedures they will undertake.  It also recommends that the facility define patients they consider at increased risk, and that those patients be cared for by a pediatric anesthesiologist. 

-- From Lucy Everett, M.D., Seattle, WA

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

QUESTION 1:

I work at a free-standing surgery center across from a medical center. Recently, a surgeon wanted to schedule an I & D of a breast abscess on a pregnant patient scheduled for an elective c-section in a few days. I was hesitant because of the risk of inducing labor, but more importantly, fetal distress.  Is it wise to do this at a free-standing ASC?  Should continuous fetal monitoring be utilized in this situation? If monitoring is used, is it incumbent to have the availability for an immediate c-section should problems arise?  Are there any limitations on what procedures and when they can be performed as an out-patient on the pregnant patient?

-- From Steven Spiro, M.D., Mission Hills, CA

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