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ABSTRACT

Patient safety for office-based surgery is multifactorial issue, and many of the variables have been widely discussed in the literature. However, the ideal anesthetic management of patients in the office setting remains an evolving debate. It is the author’s contention that many office-based anesthetic techniques and concepts are a vestige of days when only minor procedures were performed in the office. However, with the growth of office-based anesthesiology as a specialty and the expanding repatoire of involved surgical cases, the office-based surgical suite must have the same, or higher, standards of care as an accredited multispecialty Ambulatory Surgery Center (ASC) or hospital. To that end, the author introduces the concept of a Single Specialty Surgicenter (SSS) and discussed specific anesthetic techniques consistent with the safety guidelines of the American Society of Anesthesiology, which also optimize OR efficiency and the patient’s peri-operative experience.

The safety of office-based surgery has been an ongoing matter of speculation. Even the term, office-based surgery, seems to imply some rudimentary procedure done in the back room by the kitchen! Each time there is a high profile fatality in the office setting, this impression is further imprinted in the minds of the general public. However, when cosmetic surgery is performed by a board certified plastic surgeon, within an accredited facility, with an appropriately trained OR staff, then the term Single Specialty Surgicenter (SSS) more accurately reflects the focused patient care that this environment is uniquely capable of delivering.

The first step in patient safety is to educate our patients such that they can make an appropriately informed decision about the surgeon and facility where they have chosen to have their surgery. There are four cornerstones to the definition of an SSS which correlate with the following four questions, which we encourage our patients to ask each surgeon with whom they consult:
  1. Is your surgeon certified by a board that is recognized by the American Board of Medical Specialties (AMBS)? i.e. not just a “cosmetic surgeon”.
  2. Does your surgeon have privileges to perform the proposed surgery at a nearby hospital? Thereby subject to pier review.
  3. Is the facility accredited by a national agency? Such as AAAASF, AAAHC, or JCAHO.
  4. Are the appropriate personnel available to rescue a patient from the potential complications of General Anesthesia? As the American Society of Anesthesiology state: “anesthesiologist participation in all office-based surgery is optimally desirable”.1

Villa reported that Florida’s office-based surgery centers had a twelve fold increase in mortality compared with freestanding multispecialty ambulatory surgery centers (ASC) in Florida.2 Since then, Clayman presented more detail on the Florida data, spanning six years, and indeed noted a 1:13,000 mortality rate, although only 11 of the 47 fatalities were in the hands of a board certified plastic surgeon.3 In comparison, Morello’s benchmark for office-based mortality in accredited facilities is 1:57,000.4

Evidently, not everybody is practicing up to the same standard of care. Clayman eloquently stated that “(We must) continuously improve this culture…specifically related to esthetic procedures administered in nonclinical settings my amateur, or unqualified practitioners, with a misrepresentation of their credentials and training.”5 To that end, the Society of Ambulatory Anesthesia (SAMBA) recently launched its SCOR system, the Samba Clinical Outcomes Registry, at their October 2009 Conference in New Orleans. The registry is a voluntary process whereby multispecialty ASCs and Single Specialty Surgicenters/office-based surgery centers can report any untoward events, hospital admissions and mortalities. This national database will then serve as a specialty specific benchmark for comparison.6 Only by establishing the safety record of reputable practices can we highlight the charlatans and bring them to the attention of unsuspecting patients and their respective state medical boards. A practice that’s performing according to the characteristics of an SSS should embrace the SCOR system when it eventually becomes mandatory.

Ultimately an SSS should have the same standard of care as an ASC and the same level of accountability. Future studies should be able to demonstrate that optimizing patient safety directly correlates with improved OR efficiency, improved patient perioperative experience, and an improved professional satisfaction for everybody within that OR. Indeed, task-specific ICUs such as renal units and burn units have already been demonstrated to have increased safety and efficiency.7 Similarly, a SSS may even have an improved safety record for ASA 1-2 patients over a typical hospital! Further studies are warranted. The author would hypothesize that just as the last twenty years saw the exitus of patients from tertiary care hospitals to ASCs; the next twenty years will see an exponential growth in specialty-specific surgicenters which, through improved efficiency and outcomes, will contribute significantly to a competitive reformation of our national health care system.

In 1999, the Institute of Medicine published their infamous report: To err is Human, in which they suggested that between 48-98,000 deaths occurred nationally as a consequence of medical errors.8 However, within that report the specialty of anesthesiology was given accolades for its progress in patient safety. In the 1980’s mortality rates were quoted in the range of 1:10-20,000, and two decades later perioperative mortality for ASA 1-2 ambulatory patients is in the range of 1:200-250,000. Many anecdotal reports have established the safety of office-based surgery. Hoefflin published a series of 23,000 patients done with a traditional general endotracheal anesthesia technique with an excellent safety profile (zero fatalities and no “significant complications”), however, they experienced a 5% post-op nausea/vomiting (PONV) incidence, which although much better than the 20-30% hospital rate of PONV, is unacceptably high for today’s aesthetic plastic surgery suite.9 Bitar’s group in Charlotte published a series of 3515 patients done with “MAC” anesthesia, again with no fatalities, and a PONV rate of 0.2%.10 That same year, Byrd in Texas published a series of 4316 patients with a similar safety and nausea profile, but the anesthetic was tailored to the surgeon’s needs and the patient’s risk factors, therefore either utilizing general anesthesia or MAC.11 The most recent anesthesia related article in the American plastic surgery journals is Blake’s report of 4800 “MAC” cases which will be alluded to later in this paper.12

The choice of MAC versus general anesthesia is a pivotal point in regards to patient safety. Common consensus would say that MAC is much safer that general, which breeds a bias toward informing patients that they will only receive “IV sedation” or “twilight anesthesia.” An “old school” mentality would say that “it’s not general unless it’s general endotracheal anesthesia.” And there is some historical precedent to that notion. A traditional hospital based anesthetic would involve an induction, paralization, intubation, mechanical ventilation and an analgesic guestimation. Patients would be given a relatively small dose of opioid so that they would wake up soon after the muscle relaxant was reversed. They might get to the recovery room on a timely basis (after a physiologic jump start), but they would soon be in pain. The recovery room nurse then loads the patient with morphine which leads to re-somnolence, nausea, and a prolonged PACU stay.

In contrast, a modern ambulatory general anesthesia technique puts a strong emphasis on pre-emptive analgesia, a balanced intravenous pharmacological regimen, maybe a brief time of assisted ventilation but soon converting to spontaneous ventilation with careful narcotic titration. Ideally, the patient is never stimulated, which means they wake up smoother, more clear-headed, and with less nausea.

Total Intravenous Anesthesia (TIVA) has been around for 20 years, but recently the term is being discussed among plastic surgery circles. The word “total” seems to have two meanings: certainly it implies that the entire anesthetic is delivered via the IV rather than inhalational agents; however, among anesthesia circles the word “total” implies that the patient is receiving a total balanced anesthetic, i.e. Total Intra Venous General Anesthesia. This latter definition would also be consistent with the American Society of Anesthesia’s (ASA) current definition of general anesthesia which states that a general anesthetic occurs when a patient in “unaware of, and unresponsive to a painful stimulus” irrespective of what agent was used to achieve that state, and irrespective of what airway support, if any, is being used.13 The author would therefore caution surgeons that they may not be providing appropriate informed consent when using phrases such as “twilight anesthesia” or “room air general,” which are not only inaccurate, but neither are terms recognized by the ASA.

MAC has similarly gone through an evolution of definition. It used to merely stand for Monitored Anesthesia Care… i.e. someone was sitting on a stool, watching the monitors. It did not imply the use of sedatives, although this was often inferred by both surgeons and anesthesiologists. Over time MAC evolved to imply “local anesthesia with monitored care and sedation” or “local Mac” for short. The ASA House of Delegates recently redefined MAC to correlate with modern clinical circumstances. They state that MAC requires the clinical judgment of a physician (anesthesiologist or supervising surgeon) to adjust the level of sedation according to the clinical needs of the surgeon, balanced with the co-morbid risk factors of the patient. They state that “while MAC may include the administration of sedatives and/or analgesics often used in moderate sedation, the provider must be prepared and qualified to convert to General Anesthesia when necessary.”(author’s italization)14 So, MAC could indeed be similar to moderate sedation with local, but at other times it may become a Total Intravenous General Anesthetic!

Of course, the only way to know where the patient lies on this continuum of sedation is to monitor the target organ, the CNS. There are several brands of neurophysiologic monitors on the market, but the most data is available for the BIS monitor (Aspect Medical Systems, Inc.). These monitors not only measure the level of sedation throughout the MAC continuum, but they also allow the anesthesia provider to use a lighter plane of anesthesia (historically we would overdose a patient rather than risk recall,) there is a cost savings because less pharmaceutical agent is used, and the patient has a smoother emergence having received “just enough” anesthetic. And there may be less recall, but ironically this is the one factor that has yet to be definitively proven even though it was the initial proposed incentive for the use of these devises.

Briefly, the BIS monitor measures a patient’s EEG and a smart computer translates those waveforms into a single palatable number on a scale of 0 to 100, 100 being a perfectly awake patient. A range of 70 – 100 is conscious sedation (moderate sedation, or “twilight anesthesia”). Between 60 and 70 is deep sedation (if the patient arouses with a painful stimulus), and between 40 and 60 is well accepted as the general anesthesia range. There is no reason to have a patient with a BIS less than 40 unless we are doing a deep circulatory arrest … hopefully not in the office setting!

A simple study demonstrating the use of a BIS monitor involved 595 patients who were scheduled to have conscious sedation for colonoscopy. The average BIS value for these patients was 49 (well within the accepted general anesthesia range), and 78% of the patients had a BIS < 60 for more than 5 minutes. Of these, 6% had an adverse event, most commonly oxygen desaturation. The authors concluded that “deep sedation correlating with BIS values associated with GA may lead to adverse events.”15 This objective data proves the clinical suspicion of many anesthesiologists that many of our MAC cases are indeed general anesthesia with an unprotected airway.

But is this just semantics, or is there a real patient safety issue here? An effective answer requires an historical perspective:

An ether anesthetic was, by all accounts, a universally nauseating experience for patients, and carried significantly more danger by today’s standards. It required dripping the agent onto a mask covered with gauze, and the patient would slowly become anesthetized. The problem was that patients would linger in stage 2 of induction (stage 4 being a surgical plane of anesthesia.) Stage 2 is the “excitation phase” when a patient is most prone to changes in heart rate, blood pressure, arrhythmias, breath holding, salivation, laryngospasm, bronchospasm, regurgitation, and potential aspiration. The introduction of Pentathal (sodium thiopental) revolutionized the safety of anesthesia, because now a patient could go through stage 2 of induction in a matter of seconds rather than minutes. Propofol has a similar onset as an induction agent, but with a much better anti-nausea profile.

Now imagine that you have a patient who is undergoing a rhytidectomy. The patient is breathing spontaneously via a nasal cannula, possibly with an oral or nasal airway, and appears to be doing well, unresponsive to the surgery, with an oxygen saturation of 91%. We have already established from the BIS data that there is a high likelihood that this patient is venturing into the realm of general anesthesia. And since this patient is receiving a continuous infusion of propofol rather than an induction dose, they are yet again lingering in stage 2 of anesthesia. As such, patients are being exposed to similar risks of an ether anesthetic!

Every time the patient requires a chin lift, they have already experienced partial airway obstruction. There is still a powerful and primitive instinct for the diaphragm to keep contracting, but the contractions can not always overcome the upper airway obstruction, leading to “rocking respirations” and a potentially false sense of assurance. Each diaphragmatic contraction results in negative intrathoracic pressure and predisposes the patient to negative pressure pulmonary edema. All the while, oxygen is still being delivered, but not introduced into the pulmonary system. It has no where to go except to spill into the surgical field where it is potentially ignited by the Bovie and then acts as the calalyst for the surrounding drapes which become the fuel for the subsequent fire.

Figure 1 depicts the hemoglobin-oxygen desaturation curve. If this same patient were to receive 100% FiO2 via an LMA or ETT then the partial pressure of arterial oxygen (PaO2) would be as high as 600 mmHg. However, our patient with the nasal cannula has an oxygen saturation of 91% which correlates with a PaO2 of around 60, or only 10% of the potential arterial oxygen carrying capacity, which correlates directly with the tissue oxygenation. Belda demonstrated that supplemental perioperative oxygenation clearly leads to a decrease in surgical site infections.16 Many of these patients are also cold, and shivering increases oxygen consumption up to 600%. Finally, consider that most of these patients are receiving three synergistic respiratory depressants: an opioid, a benzodiazepine, and propofol. Most of these patients have an EtCO2 of 50-60 mmHg, but it would not be unusual to have that number to climb to 70 or 80 if it were not being monitored – twice the normal value. Now we have the perfect trifector of a cold patient, who is relatively hypoxic, and significantly acidotic, which could certainly predispose the patient to delayed wound healing.

For those who still consider these arguments to be hypothetical physiology, consider Bhanaker’s paper published in Anesthesiology. He looked at the ASA’s Closed Claim data, which is collected from 35 national medical liability companies, and represents all the cases involving an anesthesiologist that have gone through the litigation system. This is very unique and powerful risk stratification data. The first number of interest is that 50% of these litigation cases involved head/neck surgery, presumably associated with the shared airway. He noted that among the cases involving general anesthesia, 40% resulted in death or permanent brain injury. He then noted that among the cases involving MAC, 40% resulted in death or permanent brain injury. The exact same risk!17 Furthermore, 41% of these cases were deemed to be clearly preventable if there had been better monitoring, improved vigilance, or even if the audible alarms were turned on.

Bhanaker’s paper warranted an editorial comment in that month’s journal which Hug entitled, “MAC should stand for Maximum Anesthesia Caution, not Minimal Anesthesiology Care.” He concluded that “MAC is no less risky than general anesthesia in terms of the occurrences of permanent brain injury and death.”18 This became a loud siren throughout the anesthesia community.

Karen Domino took this same data and specifically looked at office-based surgery patients. She identified 14 patients, which granted is a small numerator, partially because of the 5-7 year delay in the litigation system. But, of those patients, 61% resulted in death versus only 21% from cases done at an Ambulatory Surgical Center.19 The aurthor would suggest that this vast discrepancy is clearly a reflection of the tendency to do office-based cases under “MAC sedation” rather than with some form of airway protection device, under the false pretext that they are providing a safer anesthetic.

Other complications identified in Domino’s study included 25% drug related mortality (wrong drug given, or the right drug, such as Dantrolene, not available), and 17% burns which was alluded to earlier.

There appears to be a distinct need for safe office-based anesthesia techniques which provide a still environment for the surgeon, fast emergence for optimum OR utilization, and are well tolerated by patients. Friedberg is credited with producing the first comprehensive textbook on Anesthesia in Cosmetic Surgery.20 He describes a propofol-ketamine technique which essentially involves a small dose of midazolam followed by a propofol infusion which is titrated using a BIS monitor to a level between 60 and 70, by definition deep sedation, not general anesthesia.21 The patient then gets a bolus of ketamine (a dissociative anesthetic with good analgesic properties) prior to local infiltration by the surgeon. With this technique the patient will inevitably move on occasion, and the knee jerk reaction would be to “push more propofol,” but Friedberg would argue that the patient is already at their target depth of anesthesia (BIS 60-70), and instead they need more analgesia. This can be given in two forms: either opioid (fentanyl) by the anesthesiologist at the risk of excessive sedation, nausea and delayed discharge; or, local anesthesia infiltration by the surgeon. If the BIS is higher than 70, then more anesthethic (propofol) is required. Therefore, the BIS monitor becomes the mediator between the anesthesiologist and the surgeon. If the surgical team uses this technique they will get excellent results in the form of patient satisfaction, assuming it is consistent with the surgeons “style” of operating, given that it is a high maintenance technique.

Barinholtz is not as much of a ‘purist’ as Friedberg in that he does not mind using modest doses of opioid in conjunction with an aggressive anti-emetic regiment, and pre-emptive analgesia in the form of local anesthesia by the surgeon. When he describes a SAFE anesthetic technique, he invokes the acronym “Short Acting Fast Emerging” anesthesia.22 As with Friedburg, he also emphasizes the use of a neurophysiologic monitoring to titrate the propofol infusion. A majority of his patients are managed with a Laryngeal Mask Airway (LMA), with spontaneous ventilation. This approach avoids the use of muscle relaxants (paralyzing agents), but it allows periodic assisted ventilation during stimulating periods of surgery, and has the significantly improved safety of a secure airway and delivery of a higher FiO2.

Our practice has independently incorporated techniques similar to Barinhotz. In our experience, as the surgeon is closing, the patient is still numb from the local anesthesia, the sedation can be titrated down (guided by the BIS monitor) and the LMA can often be removed deeply with the anesthetic essentially becoming a true moderate sedation before the dressings go on. Furthermore, opioids can be titrated to the patient’s respiratory rate prior to emergence. This is a very efficient technique in terms of OR utilization since the patient’s wake up time is a non-factor in terms of turnover time; and since the patients are never stimulated, we enjoy a 99% patient satisfaction score.23

Even though these patients are rarely intubated, have no doubt that they are under general anesthesia given that they do not respond to a painful stimulus. As such, capnography is essential. A caprograph is the gold standard for assessing ventilation. i.e. the exchange of oxygen and carbon dioxide. Even if a surgeon has limited understanding of capnography, with a glance toward the monitors they can see the waveform and be reasonably assured that their patient is breathing appropriately. If they don’t see the waveform, then they need a more vigilant anesthesia provider! The main benefit of capnography is that it provides real time identification of airway obstruction, rather than waiting for the PaO2 to fall over a period of minutes before it is recognized by the pulse oxymeter in the form of a drop in SaO2 (see figure 1). Furthermore, capnography is not just a guideline for monitoring, but an absolute standard of care, according to the ASA, for both deep sedation and general anesthesia.24 The ASA, of course, recognizes that most deep sedation cases have significant potential to become general anesthesia.

As alluded to earlier, Blake published a report entitled Office-Based Anesthesia: Dispelling Common Myths.25 By his own description, he uses “deep sedation with a propofol ketamine infusion combined with local anesthetic (plus) intercostal nerve blocks.” The use of nerve blocks is beyond the scope of this article, but instead the reader should focus on the definition of “deep sedation.” Without the use of neurophysiologic monitoring it is difficult to objectively define the level of sedation; however, he uses four synergistic sedatives (propofol, ketamine, midazolam and fentanyl,) requiring the use of an oral airway which is only tolerated by a patient with a diminished gag reflex – suggestive of general anesthesia. His safety profile is reflective of vigilant care (“the best monitor in the OR is a vigilant anesthesiologist”26) but it does not obviate the use of capnography for both deep sedation and TIVA. Blake’s results are therefore not necessarily reproducible.

Patient safety is being compromised because many office-based surgical suites are under the false impression that it is safer to push the limits of IV sedation rather than accepting and recognizing that these patients are indeed generally anesthetized and mandate the appropriate precautions. If the problem is a perceived concern as to whether a patient will accept having a general anesthetic in the office, the author suggests using an airplane analogy:

“When I fly, the plane cruises at 30,000 feet, which seems like an awfully long way up. But, at 20,000 feet it’s among the clouds and turbulence. Similarly, general anesthesia may seem too deep, but if you’re responding to the surgery, then you’re among the turbulence in regards to your hear rate, blood pressure and breathing. It’s actually safer to go deeper.” Assuming, of course, that your facility is set up as a Single Specialty Surgicenter as previously defined.

Therefore, always prepare for general anesthesia, no matter what you call it! Preferably call it what it is: if the patient is not responding to a painful stimulus then its general anesthesia irrespective of the pharmaceuticals used or the airway management technique. Use capnography, especially for your TIVA patients, knowing that this is a labor intensive technique that requires the most vigilance from your anesthesia provider. The surgical suites that are getting the highest patient satisfaction reports are the ones that have figured out the symbiotic relationship between anesthesia and surgery, with the BIS monitor acting as the mediator. And embrace mandatory reporting when it comes, because it will be the most effective way of weeding out those surgeons who are not practicing up to the standards of a Single Specialty Surgicenter.

DISCLOSURES

The author has no disclosures with respect to this commentary.

REFERENCES

  1. Office-Based Anesthesia. Considerations for Anesthesiologists in Setting Up and Maintaining a Safe Office Anesthesia Environment. 2nd Edition. American Society of Anesthesiologists. 2008. p52
  2. Vila H, Soto R, Cantor B, et al. Comparative outcomes analysis of procedures performed in physician offices and ASC. Arch Surg. 2003;138:991
  3. Clayman M, Seagle B. Office Surgery Safety: The myths and truths behind the Florida moratoria – six years of Florida data. Plast Reconstr Surg. 2006 Sep;118(3): 777-785
  4. Morello D, et al. Patient safety in accredited office surgical facilities. Plast Reconst Surg. 1997 May; 99(6): 1496-1500
  5. Clayman M, Clayman S, Steele M, Seagle M. Promoting a culture of patient safety: A review of the Florida data: What have we learned in 6 years and the need for continued patient education. Ann Plast Surg. 2007 Mar; 58(3): 288-91
  6. http://www.sambahq.org/page/clinical-outcomes-registry-scor-2
  7. Carlisle A. How will we pay for trauma and critical care? Audio-Digest Anesthesiology. 2009 Nov; Vol 51, Issue 22
  8. Kutchta K. Anesthesia patient safety: It is not what you think it is. Audio-Digest Anesthesiology. 2009 May; Vol 51, Issue 10
  9. Hoefflin S, Bornstein J, Gordon M. General anesthesia in an office-based plastic surgical facility: a report on more than 23,000 consecutive office-based procedures under general anesthesia with no significant anesthesia complications. Plast Reconst Surg. 2001 Jan; 107(1): 243-51
  10. Bitar G, Mullis W, Jacobs W, Matthews D, Beasley M, Smith K, Watterson P, Getz S, Capizzi P, Eaves F 3ed. Safety and efficacy of office-based surgery with monitored anesthesia care/sedation in 4778 consecutive plastic surgery procedures. Plast Reconstr Surg. 2003 Jan; 111(1): 150-6
  11. Byrd H, Barton F, Orenstein H, Rohrich R, Burns A, Hobar P, Haydon M. Safety and efficacy in an accredited outpatient plastic surgery facility: a review of 5316 consecutive cases. Plast Reconst Surg. 2003 Aug; 112(2): 636-41
  12. Blake D. Office-Based Anesthesia: Dispelling Common Myths. Aesthetic Surgery Journal. 2008 Sept/Oct; 28(5) 564-572
  13. American Society of Anesthesiologists: Standards, Guidelines and Statements; Practice parameters. Continuum of Depth of Sedation: Definition of General Anesthesia and Levels of Sedation/Analgisia. Committee of Origin: Quality Management and Departmental Administration.(Approved by the ASA House of Delegates on October 27, 2004, and amended on Oct 21, 2009
  14. American Society of Anesthesiologists: Standards, Guidelines and Statements; Practice parameters Position on Monitored Anesthesia Care. Committee of Origin: Economics. (Approved by the House of Delegates on October 21, 1986, amended on October 25, 2005 and last updated on September 2, 2008)
  15. Abstracts probe deep sedation and deep hypnotic time. Journal of the Anesthesia Patient Safety Foundation Newsletter. Vol 23(4); p64 referencing Abstract A192.
  16. Belda. Supplemental perioperative oxygen and the risk of wound infection. JAMA  2006; 294: 2035
  17. Bhananker S, Posner K, Cheney F, Caplan R, Lee L, Domino K,. Injury and liability associated with monitored anesthesia care: a closed claim analysis. Anesthesiology. 2006 Feb; 104(2): 228-34
  18. Hug C, Jr. MAC should stand for Maximum Anesthesia Caution, not Minimal Anesthesia Care. Anesthesiology. 2006; 104: 221-3
  19. Domino K. Office-Based Anesthesia: Lessons learned from the Closed Claim Project. American Society of Anesthesiology Newsletter. 2001June; Vol 65(6): 9-11 and 15
  20. Friedberg B. Anesthesia in Cosmetic Surgery. Cambridge University Press. 2007
  21. Friedberg B. Propofol-Ketamine Technique: Dissociative Anesthesia for Office Surgery (a 5-year review of 1264 cases.) Aesthetic Plastic Surgery. 1999; 23:70-75
  22. Barinholtz D. Personal correspondence. SAMBA  mid year meeting. October 21 2005
  23. http://www.RestAssuredMD.com/endorse.htm
  24. American Society of Anesthesiologists: Standards, Guidelines and Statements; Practice parameters Basic Anesthetic Monitoring Standards. (Approved by the House of Delegates on October 21, 1986, amended on October 25, 2005)
  25. Blake D. Office-Based Anesthesia: Dispelling Common Myths. Aesthetic Surgery Journal. 2008 Sept/Oct; 28(5) 564-572
  26. Barash P. Personal Correspondence. Residency training: Yale-New Haven Hospital. 1996.

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