Stents are the ingenious hi-tech devices implanted in blocked coronary arteries by cardiologists, our high priests of interventional medicine. In the last 3-5 years we’ve learned unfortunately that coronary stents are not the panacea once hoped for. A major problem with stents is that they tend to become blocked off themselves unless anti-platelet medication, such as Plavix, is taken, for months or even years.

One of the main purposes of pre-surgery evaluation is to find out whether a patient has coronary artery disease and is therefore at risk for having a heart attack or other heart complication during or after surgery. We used to assume that  offering these patients stents (‘re-vascularisation’) would protect them from these kinds of heart problems.

In fact, studies have shown that patients who’ve been very recently ’stented’ often have worse outcomes. For major surgery, anti-platelet drugs are usually stopped, in order to prevent bleeding. Unfortunately stopping these medications, combined with the complex effects of surgery on blood clotting, leads to a much greater chance that the stent, and therefore the artery, will block off, thereby causing the cardiac complication we were trying at all costs to avoid.

Guidelines from the American College of Cardiology, the American Heart Association, and the American Society of Anesthesiologists, now recommend postponing major elective surgery in which there is significant risk of bleeding, in patients with new coronary stents.

If you have a bare-metal stent the minimum recommended wait is 4-6 weeks. If you have a drug-eluting stent the wait is 12 months after implantation.

Decision-making (e.g. when to have the surgery, when to stop or continue medications) can be quite complex in this situation. Very often, surgery cannot be postponed, and the risks have to be carefully weighed to make a good choice.

What You Should Do

Make sure your anesthesiologist and your surgeon know that you have a coronary stent, when it was put in, what type it is, and what medications you are taking.

Assessing risks and benefits, to guide decision-making about going forward (or postponing) surgery, and about stopping or continuing anti-platelet drugs will involve a discussion between your surgeon, your anesthesiologist, and your cardiologist. With your input of course.

Reference

Practice Alert for the Perioperative Management of Patients with Coronary Artery Stents: A Report by the American Society of Anesthesiologists Committee on Standards and Practice Parameters. Anesthesiology: January 2009 – Volume 110 – Issue 1 – pp 22-23. Link.

The New England Journal of Medicine published a special study reporting the success of the World Health Organization’s Surgical Safety Checklist in reducing lives and preventing major complications after non-heart surgery. Eight hospitals in developed (US, Canada, New Zealand) and developing (India, Jordan, Kenya, Phillipines, Tanzania) countries were involved, and the positive results were seen in both settings.

The checklist involves steps at “sign-in” (e.g. verifying the patient’s identity, and the site of operation), immediately before cutting the skin (e.g. antibiotics given, X-rays are in the room), and just before the patients leaves the operating room (e.g. needle, sponge and instrument counts are complete).

The overall death rate decreased from 1.5 to 0.8%, and complications went down from 11 to 7%. This is really remarkable. If these results were achieved by a drug or a new surgical technique you can bet it would be patented immediately and be worth billions.

The explanation for such amazing results?  Use of a checklist initiates a change in mindset, culture, call it what you will, that facilitates open communication. The checklist also says that the surgeon is fallible, the anesthesiologist is fallible, the nurse is fallible, but that collectively we can help each other avoid mistakes by routinely and systematically discussing what needs to be done, and using a written list to help us all remember some key steps. Studies of human performance show that we make mistakes on routine tasks at least once or twice in every 100 times. That simply isn’t good enough in healthcare, as in other high risk human endeavors.

The fact that such checklists aren’t routinely used in the majority of the world’s hospitals is fairly shocking to many. And despite this result, it’ll no doubt take some time before such basic safety measures are embraced by ALL hospitals. Why?

As Rene Amalberti, a safety and performance expert has found, in studies across industries, there is always a tension between reliability/safety one the one hand, and productivity on the other. In healthcare we routinely stray into territory that increases risks to patients (and ourselves), not because we are cowboys, or cavalier, but because there are very real constraints on resources. We probably could do a perfect job, within the limits of medical science, if we all did one operation a day, but it would be very expensive, and all our other patients would miss out on their needed care.

It’s hard to argue against the checklist however because it’s simple to do, doesn’t cost money, and can be complete in one or two minutes.

My Advice

If you’re a patient, look for evidence that your chosen hospital is implementing checklists, across the board. Or choose another hospital.

Colonoscopy, repeated at 5-10 year intervals, is recommended to detect colon cancer after age 50. As the American (and global) population ages, more colonoscopies will be performed, and more colonoscopists are needed.

One controversy is – who is qualified to perform a colonoscopy? Family physicians with special training argue that they are, and this would certainly ease the pressure on gastroenterologists (or offer a competitive threat?).

Another contentious area is – who is qualified to provide the sedation that most patients expect? Some gastroenterologists say that sedation is so safe that they can provide, or at least supervise it, while they do the colonoscopy. Anesthesiologists would argue the contrary. (Disclaimer: I am one – an anesthesiologist).

Outside the United States, colonoscopy is often done without sedation. This may even be the norm, as discussed in an American Medical News article which reports on a center in California which has been doing these on a routine basis, in volunteers, with some success (78% completed the study without drugs).

It’s clear from this article that colonoscopy without sedation is possible in America. But that is hardly a surprise. What’s missing in this analysis, and all the controversy, is outcomes. Not the number of colonoscopies completed, which is what is reported in these studies, but how many lesions were picked up (or missed) during the colonoscopy. That’s a much more difficult study to do, but isn’t finding (or ruling out) cancer the reason for undergoing this rather unpleasant test?

Intuitively, an endoscopist who does not have the additional responsibility of sedation, or the time pressure of completing the study as quickly as possible in an unsedated patient, has better conditions to fulfill his primary role – to find cancerous or pre-cancerous lesions in the colon and rectum. But that’s just my suspicion – let’s hope the outcome studies get done.

In a study presented at the 2008 annual conference of the American Society of Anesthesiologists, investigators applied “hemispheric-synchronised” sounds (Hemi-Sync) to 60 patients undergoing outpatient surgery. Sounds are played through headphones and, according to the product website, ensure the “left and right hemispheres are working together in a state of coherence”. Patients used the Hemi-Sync before and during surgery, while control patients listened to music or a blank cassette.

A similar study (76 patients) was done in 1999, but in the current investigation the level of anesthesia was controlled using a brainwave monitor called the Bispectral Index.

Hemi-Sync is one of several gizmos marketed to harness human brain waves. Purported benefits include financial success, improved sleep, weight loss, spiritual growth and more.

Do they help with anesthesia and recovery from surgery?

Results

Hemi-Sync patients required less fentanyl (a strong analgesic) during the surgical procedure. The other outcomes, overall, were pretty similar in all the study groups, including analgesic needs after surgery, recovery time, nausea, awareness, etc.

Results from the 1999 study were rather similar.

Does it Matter?

This result suggests that Hemi-Sync is doing something useful in the brain. The study findings imply that hearing pathways in the brain are preserved to some extent during general anesthesia, and that given certain stimuli these pathways can somehow modulate pain signals coming to or processed in the brain.

The earlier study did not exactly revolutionise the practice of anesthesia. Small reductions in the need for certain inexpensive drugs are not going to change the way we do things.

A reduction in the amount of morphine or fentanyl needed during anesthesia can lead to lower rates of postoperative nausea, which would be a benefit, as nausea continues to be one of the most troublesome problems during recovery from anesthesia, especially for outpatient surgery. However this study did not find such a benefit. It probably did not have sufficient numbers to detect a statistically significant difference in the study groups.

On the other hand, there don’t seem to be drawbacks to the use of this sort of technology, other than their purchase expense. So it’s unlikly that your anesthesiologist will object if you bring your Hemi-Sync tape or MP3 to the outpatient surgery center, or anything else you choose to soothe your brain and calm its waves.

Have Jehovah’s witnesses been right all along? About blood transfusion, that is.

There is increasing evidence that a “liberal” approach to the transfusion of blood is the wrong approach. For instance, transfusion seems to increase the risk of infection. But it’s not the kind of infection that most people worry about, dread viruses like hepatitis or HIV. Rather, transfusion inhibits the immune system and leads to higher rates of so-called nosocomial, or hospital-acquired, bacterial infection (bloodstream infections, pneumonia, urinary infection).

There’s even a seldom appreciated increased risk of acquiring cancer over subsequent years.

A new retrospective study has shown that banked blood stored for more than 4 weeks is associated with more infection in the patients who receive it. Blood is scarce and expensive, and most blood banks store it for up to 42 days before administration.

What’s the right perspective? Except for certain religious groups blood transfusion isn’t evil and, as always, an appreciation of risks and benefits is necessary. Blood can be life-saving. And patients with severe heart or lung disease, for example, do poorly without transfusion in circumstances that healthier people easily tolerate.

What you can do

1. If you are in a position to do so – e.g. before elective joint surgery – it’s wise to ask a few questions of your doctor about blood transfusion. The right questions, plus a lot useful information, is contained in a nice booklet (PDF) put out by the Society for Advancement of Blood Management.
2. If you are about to undergo surgery in which significant blood loss is expected, your hemoglobin level should be checked ahead of time. A low level (anemia) detected only in hospital could lead to an unnecessary blood transfusion, avoidable through the administration of iron, by mouth, or an injection of erythropoietin, a drug that stimulates the body to produce red blood cells.

Devotees of oriental medicine will not be surprised by the finding, in the British Journal of Anaesthesia, that acupuncture reduces pain after surgery. More unexpected is that chili powder applied to the skin below the knee can produce the same effect!

In this meta-analysis fifteen studies were analysed – over 1100 patients. In each study, acupuncture was compared with control “sham” acupuncture (acupuncture applied to non-acupuncture points).

• Acupuncture patients needed less opioid (morphine-like) pain treatment at 8, 24 and 72 hours after surgery
• Postoperative pain was also significantly less in the acupuncture group at 8 and 72 h compared with the control group.
• The acupuncture treatment group had a lower incidence of opioid-related side-effects such as nausea, dizziness, sedation, pruritus (itching), and urinary retention (inability to urinate).

The authors conclude that “perioperative acupuncture may be a useful adjunct for acute postoperative pain management”. I was intrigued, and decided to explore the methods used in one of the 15 studies in a bit more detail (Kim KS, Nam YM. The analgesic effects of capsicum plaster at the Zusanli point after abdominal hysterectomy. Anesth Analg 2006; 103: 709–13).

In this study, needles were not used. This should make the technique a bit more acceptable to needle-averse patients i.e. most Westerners and all children. (The study however included no children and, as it was performed in Korea, probably no Westerners).

Capsaicin is the compound in chili peppers that makes them taste hot. Capsicum plaster (PAS) is a capsaicin mixture of powdered capsicum  and capsicum tincture on a sheet. After application the sheet is covered with an adhesive plaster. This method apparently is widely used in Korea.

The Zusanli acupuncture point (Chinese: 足三里, ST36) is four finger breadths below the lower margin of the patella and one finger breadth lateral from the anterior crest of the tibia. The Zusanli acupoint lies on the stomach meridian and is used in the treatment of lower abdominal pain. In the study, the treatments (capsaicin, control or sham) were applied 30 minutes before anesthesia and were maintained for 8 hours per day for 3 days.

PAS is “noninvasive, simple, painless, and easy to apply”. The size (5 × 5 mm²) of the patch is convenient, and capsicum gets from the patch and into the skin surface within 8–12 hours. PAS is also inexpensive ($1 per 5 sheets), especially when compared to anti-nausea drugs or to transcutaneous electrical acupuncture devices like the ReliefBand.

The Zusanli acupoint was first confirmed by the acupuncturist using an acupuncture needle. It’s not clear from the study description whether this is a prerequisite for correct application or whether you can simply apply the patch to the appropriate area  below the knee. (De-Qi is a sensation typically associated with proper acupuncture needle positioning and many practitioners say this sensation is crucial in achieving the effect of acupuncture. However, when PAS is applied on an acupoint, De-Qi is unlikely to be elicited).

The results of this pchili powder study were in keeping with the results of the meta-analysis i.e. pain levels were reduced and less analgesic medication was needed.

So, with the above caveat about plaster application in mind, I conclude that PAS may be a useful addition to standard pain treatment in patients having abdominal surgery. It may be especially helpful for those in whom usual analgesic medications have been less successful, or have lead to side-effects, and for individuals who simply prefer non-drug treatments. I can’t wait to offer it to my next hysterectomy patient, if I can just get my hands on some PAS plasters!

Whether anesthesia, or surgery, or some combination of the two, have long-lasting effects on the brain of children is an important question which researchers are trying very hard to answer. Three new studies provide some cause for concern.

In a non-clinical, (epidemiologic), study from Columbia University the authors used databases to review cases in which children had hernia surgery in the first four years of life. They found that these children, compared with a control group, had almost twice as much risk of subsequently developing behavioral or developmental disorders.

In a second study, from the Mayo Clinic, the risk of learning disabilities in children after a single anesthetic was not different from a control group but the risk did increase after two or three anesthetics and in the cases where the duration of the anesthetic was longer than 2 hours.

Finally, a Dutch study of children who had urologic surgery. “Neurocognitive” development was evaluated by means of a questionnaire completed by parents. Children who had their procedures before the age of two years had lower scores but the study wasn’t large enough to say with any certainty that this age cut-off is important.

These studies will be presented at the annual meeting of the American Society of Anesthesiologists in October 2008, so the details aren’t available and the studies haven’t been extensively peer-reviewed.

Why did these studies get done?

Previous animal research has shown that anesthesia may harm the developing rat brain. It is not yet known whether this is true for humans. One of the problems in this area of research is that it’s hard to separate the effects of anesthesia from the effects of surgery. Surgery is trauma. Trauma triggers inflammation and other body responses that affect the brain, and other organs. And obviously we cannot do human studies in which surgery is done without anesthesia.

These findings suggest an urgent need to do further research. We need bigger, prospective (forward looking) studies in which children who have surgery and a control group are followed up, and standard methods for assessing neurologic, cognitive and behavioral development are used, rather than administrative databases or questionnaires alone.

What you can do

James Cottrell, at SUNY in Brookly, New York, a well known neuroanesthesiologist recommends that “until and unless we establish that human fetuses and newborns do not suffer anesthetic neurotoxicity” (my emphasis) we should:

• Minimize or avoid anesthesia in the third trimester (last 3 months) of pregnancy
• Delay surgery in preterm and early postnatal infants
• Avoid specific anesthetic agents that seem the most problematic in animal studies (ketamine, nitrous oxide)
• Limit surgical time whenever possible

This advice is easier to issue than to follow. Surgery in the last part of pregnancy or in newborn children is never lightly undertaken. However there are sometimes occasions in which the choice to delay surgery until later in childhood is an option, and these studies should give more weight to a decision to delay when possible.

Deep vein thrombosis (DVT) and pulmonary embolism (PE) – “blood clots” – kill about 100,000 Americans each year. Many blood clots occur after routine elective surgery – especially spine surgery and major surgery on the hip or knee.

An excellent consumer guide to the risks, prevention and treatment of blood clots can be found here.

The Office of the Surgeon General in the US recently called for action to address this major public health problem. The Surgeon General’s Call to Action to Prevent Deep Vein Thrombosis and Pulmonary Embolism documents the problems DVT and PE pose, as well as strategies to reduce the risk of developing the conditions. Clearly we need to improve public knowledge about risk factors, triggering events, and symptoms of the disease, which is often silent.

Before any surgical procedure, particularly those requiring more than a day or so in hospital, you should be evaluated for any risk factors for a blood clot. People at risk need preventive measures, which can include anticoagulants, like heparin, special stockings, or the use of automated calf compression devices.

Rapid mobilisation – i.e. getting out of bed – is one of the best ways to avoid blood clots and is one of the reasons why patients having outpatient or day surgery very seldom need specific preventive treatments.

Blood Clots and Surgery

Any injury to the body, whether due to surgery or trauma, increases the risk of a blood clot, because the injury stimulates the body’s clotting processes. Most of these blood clots occur within 2 weeks of the event, but some happen within a few hours or even during the operation. DVT/PE also can occur up to several months after surgery or major trauma.

Certain types of surgery and certain types of trauma are especially likely to lead to blood clots, including:

• Pelvic (gynecological and urological) surgery
• Orthopedic surgery (including hip replacement or fracture repair)
• Spinal cord paralysis
• Multiple limb fractures
• Pelvis/hip socket injury.

Signs and Symptoms of Blood Clots

Unfortunately the symptoms are sometimes mild, and easily confused with other conditions. If you have a blood clot in your leg (DVT) you may notice:

• New swelling in your arm or leg.
• Skin redness.
• Soreness or pain in your arm or leg.
• A warm spot on your leg.

If a blood clot travels to your lungs (PE) may have:

• A hard time breathing.
• Chest pain.
• A fast heartbeat.
• Fainting spells.
• A mild fever.
• A cough, with or without blood.

What You Can Do

1. Get checked. All hospitalized patients should be evaluated upon admission to assess their risk for DVT/PE. Many different sets of guidelines have been published but every hospital is supposed to have one that they adhere to. Not everyone needs prophylaxis (preventive treatment) but make sure you have been assessed and a decision made by your doctor(s) on whether you need anticoagulants or other preventive measures.
2. Get checked again. If you stay in hospital you should also be assessed regularly thereafter, both for the need for prevention, and for the development of blood clots.
3. Familiarise yourself with the symptoms of blood clots and don’t hesitate to seek help if you are worried.

Reference

Your Guide to Preventing and Treating Blood Clots. AHRQ Publication No. 08-0058-A. Agency for Healthcare Research and Quality, Rockville, MD. August 2008. http://www.ahrq.gov/consumer/bloodclots.htm

Ten Eight Rules for Safe Drug Use

Before surgery the medications you take should be listed accurately and in detail – their names, doses, and the times at which you take them. Medications that you purchase without a prescription may be as important as those prescribed by your doctor.

Why is a medication history important before surgery? Your anesthesia provider needs to know what you’re taking. Your surgeon and the hospital nursing staff too. Drugs that you take may interact with anesthesia drugs, or with drugs prescribed specifically for your recovery – e.g. antibiotics or anticoagulants (“blood thinners”). Drugs you take on a regular basis are usually taken for a good reason so should be continued during a hospital admission, and afterward. Some drugs however, such as anticoagulants, may need to be stopped, or surgery cannot go ahead.

“Adverse drug events” (ADE) are surprisingly common, both in and outside hospitals, especially among the elderly, so there may even be unrecognized problems with the combination of drugs you take, though these are best managed by your primary care doctor.

How do you avoid such problems? Here are a few rules that can help keep you out of trouble:

Rule 1: Have regular “brown bag sessions” with your primary doctor to review all your drugs, their doses and the reason you are taking them.

Rule 2: Find out if you are having any adverse drug reactions.

Rule 3: Assume that any new symptom you develop after starting a new drug could be caused by the drug.

Rule 4: Before leaving your doctor’s office or pharmacy, make sure the instructions for taking your medicine are clear to you and a family member or friend.

If you’re in the hospital things get a bit more tricky, because there are more people involved in the prescription, transcription, distribution and administration of drugs. And, more drugs. Also, you may not always be in a state where you are able to pay attention to what is being done for you, or told to you, by doctors, nurses, and hospital staff.

Rule 1: Take a friend or family member with you who can ask questions about your drug treatment when you are not fully able to play your part in the conversation.

Rule 2: Make sure you understand the instructions for taking any new drugs before you leave the hospital, including the dose, the timing, and any side effects to look out for.

Rule 3: Ask what any new drug is for.

Rule 4: Make sure the new drug is not the same as, or similar to, something you have previously had a reaction to. In other words, dont’ be embarasses to remind your doctors or nurses about any allergies or adverse reactions to medication that you have had.

A study in the Canadian Medical Journal, accompanied by a commentary, looks at statins and postoperative delirium.

This condition (“an acute change in mental status that is worrisome to patients and families”) is a big concern for many elderly patients (and their families) having major surgery. Unfortunately we don’t yet know enough about the predisposing factors and direct causes to do very much about preventing postoperative delirium, apart from avoiding some things which are obviously bad for all patients (e.g. low blood pressure, inadequate oxygen, etc). Delirium increases the average length of a hospital stay by about a week, is associated with a variety of complications and increased costs, and may even be linked to permanent brain deficits.

This study suggests that statin drugs predispose to postoperative delirium. Is the conclusion correct? Should it change medical practice, which currently strongly favors the continuation of statins after surgery because of their protective effect on the heart?

The Canadian study uses epidemiologic methods to look back at a large number (over 500,00) of hospitalised patients, and, using sophisticated analytical and statistical tools, concludes that statins taken before surgery increase delirium by about 30%. The authors suggest that one of the effects of statins, which influence the control of very small blood vessels and their supply of blood to brain tissue, may lead to ischemia (inadequate oxygen) for parts of the brain, and hence delirium.

In my view, and the view of the commentator, the findings are worrisome, but the study design isn’t strong enough to influence medical practice just yet. For example, the number of patients the study found with delirium is less than a tenth of the likely true number and these patient may differ in some systematic way from the norm.

The findings are strong enough that it is now important for us to study this issue in a better way. That means a randomised, controlled clinical trial in which statins are stopped in some patients, continued in other (control) patients, and delirium is diagnosed in a through way.

What you can do

Stay on your statins if you are to have surgery.

Always check with your doctors on what medications you need to continue, or stop, before anesthesia and surgery.

References

For a list of risk factors for postoperative delirium, see this table within the Canadian Medical Assocation Journal article referred to above.

An excellent summary of postoperative delirium (for a medical reader) is found on the ASA website here.