BIS monitoring: "busted"

A few years ago, a new anesthesia gadget called the BIS monitor, short for bi-spectral index, made the headlines. The claim was that this new monitor would ensure that the patient was truly "asleep" and unaware of the surgery...but not getting too much medication either. It works by calculating a score from EEG (brain-wave) patterns. The BIS monitor divided anesthesiologists - some felt it was the latest and greatest thing, others felt it was not particularly accurate.

This week, in the New England Journal of Medicine, a randomized study compared awareness after anesthesia in patients treated with standard monitoring versus the BIS monitor.

More than 6,000 patients were randomized to receive intra-operative monitoring by either BIS or End-Tidal Anesthesia Concentrations (the standard). Forty-nine patients reported intra-operative memories. Expert review determined that 9 of these patients (0.15%) had truly experienced definite awareness.

The group with standard (End-Tidal monitoring) had a lower incidence of awareness: compared to 7 out of 2,861 patients in the BIS group, only 2 out of 2,852 patients in the standard group experienced definite awareness (p=0.98).

There was no statistically significant difference in the rate of intra-operative awareness between the two monitoring systems.

Editor's note: This is a good study that gives clinically helpful information. The BIS monitor isn't magic - there's still a lot about the state of consciousness (or lack thereof) that we don't fully understand. So, it's not surprising to me that the BIS monitoring system isn't foolproof.

Problem or panacea: "awake" cosmetic surgery

More and more, I see ads by non-plastic surgeons touting the alleged advantages of having major elective procedures, such as a tummy tuck or a breast augmentation, done "awake" - under local anesthesia. Invariably, these ads tout "avoid risky general anesthesia", or "quick recovery".

While liposuction under tumescent (local) anesthesia is an accepted and validated technique, performing breast augmentation or tummy tucks while awake is very controversial, to say the least. The New York Times recently did an investigation on this issue - their article is here (link)

Typically, these procedures are heavily advertised by cosmetic surgeons who are not board-certified in plastic surgery, and who do not have hospital privileges to work in the operating room. Their offices are usually not accredited, inspected surgical facilities. And they don't typically have an anesthesiologist monitoring the patient.

Really, I feel that the "local anesthesia" angle is a bit of a dodge. It's a clever bit of marketing spin. The reason most of these "wanna-be's" promote this is because it's their only option for anesthesia....they usually can't get the hospital privileges or work in accredited surgery centers, due to lack of credentials.

There are also real disadvantages to the "local only" technique:
- It can be hard to numb large areas completely, even with the tumescent technique. Remember, just like when you visit the dentist, it can take a few painful shots before the injected area is numb.
- If the local isn't working 100%, the patients may be fully aware and in pain, as the procedure goes on. I wouldn't wish that on my worst enemy, thank you.
- You can't get satisfactory muscle relaxation with just local anesthesia, either - which is important for procedures like tummy tucks, or sub-pectoral breast augmentation.
- it isn't good for patients who are nervous, or who are resistant to lidocaine.
- lidocaine, the most commonly used numbing agent, isn't risk free. Toxic doses can occur, resulting in seizures and cardiac arrhythmias.

If you want a rapid recovery from anesthesia, use an expert anesthesiologist, who can monitor the patient, and give them exactly the right doses of medication, keeping them comfortable, but not over-sedated.

Modern anesthesia, administered by an anesthesiologist in an accredited facility, is actually very safe. The risk of something bad happening under anesthesia is less than 1 in 57,000, according to recent studies. Essentially, you are far safer under anesthesia than you are driving your car to work every day.

As for the claims of "quicker recovery", the recovery from the surgery depends more on the nature of the surgery, on delicate handling of the tissues by the surgeon, good hemostasis, and avoidance of tension on the tissues, all of which are skills that are stressed in Plastic Surgery school.

If I were to have a surgery done, I don't want to feel it, see it, or smell it, thank you very much. Wake me up when it's all over. Most of my patients feel the very same way.

Redheads & Surgery

Back when I was a general surgery resident, one of the sayings passed down from our surgery professors was that "redheads were trouble", because they seemed to bleed a bit more than the average patient during a typical procedure. It was like a surgical superstition, a part of surgical lore that hadn't been proven scientifically, and yet was well known by all wise surgeons.

In the last few years, some researchers have started to look at the connection between natural redheads and surgery, and it actually turns out that there ARE some interesting findings - if you are a true redhead, and not just a shade of auburn.

For those that like the technical details, red hair color results from one of several mutations in a hormone receptor known as the melanocortin-1 receptor (MC1-R). The MC1-R plays a key role in determining the type of melanin (eumelanin vs pheomelanin) that is produced within melanocytes (pigment containing cells) - and hence plays a major role in skin and hair color. When the receptor is defective, it's postulated that melanocortin levels rise - which also seems to make the body more sensitive to pain.

Researchers at the University of Louisville have published 3 separate studies on this topic. They've found that red-headed volunteers had:

1. Higher anesthesia requirements, requiring about 20% more inhaled anesthetic agent than brunettes to eliminate responses to noxious stimuli;

2. Higher resistance to lidocaine (a common numbing agent). Subcutaneous injection of lidocaine was less effective in redheads than brunettes, and the redheads were more sensitive to painful hot and cold stimuli.

3. More self-reported bruising after surgery or injury, even though all the usual lab tests for coagulation and platelet function were within the normal range.


So, the surgical lore of our senior surgery professors was right all along - watch out for those red-heads!

Do longer surgeries have a higher complication rate?

A common question around here from patients is whether they can combine surgeries - say, a tummy tuck with liposuction and a mastopexy - as one might be wanting to do in a "mommy makeover".

To answer this, we have to look at things from 2 different angles:
1) legal - what do the Florida regulations permit, and
2) medical - what do the studies looking at surgical complications find.

First of all, the applicable Florida regulations for office-based surgery state that the "maximum combined duration of anesthesia shall not exceed 8 hours." Not much of an issue there, unless somebody is planning a surgical marathon.

From the medical literature, the answer to the question relating complication rates and duration of surgery is, surprisingly, not 100% obvious. Since there hasn't been a prospective randomized study in plastic surgery patients, we only have studies from other types of surgery, and retrospective reviews to examine. So hold on, I'm going to summarize a few studies - it'll only take a minute....

Data against long surgeries:

- increased overall complication rates with longer anesthesia / surgery times in multiple studies in the anesthesia, cardiac surgery, orthopedic surgery, and urology literature. In particular, the study from the British Journal of Urology found a fourfold increase in non-urologic complications with anesthesia durations > 6 hours.

- increased rate of DVT (deep vein thrombosis) and pulmonary embolism. For example, in one orthopedic study, these potentially life-threatening complications were 3.5 times more likely when the anesthesia duration exceeded 3.5 hours for hip or knee replacement surgery, which are infamous for high rates of DVT's. More recently, the Caprini risk factor stratification system for DVT's showed prolonged anesthesia times to be an independent risk factor for DVT and PE.

- increased pulmonary complications with anesthesia times greater than 2.5 hours, in both normal patients, and especially in those with pre-existing chronic lung conditions. There are multiple studies which have shown a correlation between pulmonary complications (such as post-op pneumonia) and duration of anesthesia, for multiple different sorts of surgeries.

- increased rate of surgical site (wound) infections with longer surgeries.

- higher incidence of unplanned hospital admissions

- higher incidence of postoperative hypothermia


Data supporting combination surgeries

- no increased risk seen when facial surgery operations were combined, in a study performed at Yale University. Anesthesia / surgery duration was not associated with increased risk in this study when surgeries under 4 hours and over 4 hours were compared.

- no increase in the complication rate when aesthetic tummy and breast operations were combined in a study from a private clinic in California. However, in this single-surgeon study, all surgeries were less than 6 hours in length.

The bottom line: Combination surgeries can be performed safely, in selected patients. Despite our best efforts at prevention & prophylaxis, DVT, pulmonary embolism and pulmonary complications of anesthesia are lingering issues related to longer surgeries with general anesthesia. And when these problems occur, they can be devastating, requiring hospitalization or even ICU admission.

So, there is an upper limit, and each surgeon has to make up their own mind about what that is, until the day comes when we have really solid scientific evidence to guide our decision-making. For my own point of view, I do not typically recommend combinations of surgery exceeding 6-7 hours of planned surgery time, even for healthy patients, especially when one of the procedures is an abdominoplasty.

I really feel it is safer to divide up the surgery into two stages, if the length of surgery exceeds this 6-7 hour number. I realize that it's a major inconvenience for patients to have two separate recovery stages, so I don't make this recommendation lightly...I make it solely for reasons of patient safety. (It's certainly not for my convenience.) I know that I have lost business because of it, and that patients sometimes go to someone else who promises to do it all in one day.

I certainly don't want to gamble with your health - nor do you want me to rush through your procedures!! I much prefer to be a meticulous craftsman than a speed demon, when it comes to cosmetic plastic surgery!

So, going back to the original question: I commonly combine a breast augmentation (approx. 1 hour procedure) or a smaller mastopexy with a complete tummy tuck (3-4 hours). But I will not generally combine a major breast reduction or complex mastopexy (3-4 hours) with a full tummy tuck (another 3-4 hours), as I feel the lengthy 7-8 hour anesthesia / surgery time is too worrisome, even for healthy people.


As always - safety first.