Going To Sleep Is Free, But

Acoustic Respiratory Monitoring: What Is It?

• Categories: Anesthesia practice, Technology
• Printer Friendly|#| Trackback

An intriguing press release last week from Masimo (known for their motion artifact-resistant pulse oximeters) begins as follows:



The release then refers to "an adhesive bioacoustic sensor applied to the patient's neck and connected to a breathing frequency monitor prototype" which in turn accurately monitors respiratory rate.

If this device does what I think it does, it will become the standard of care for post-surgical patients very rapidly.  We've been looking for a way to reliably monitor respiratory rate on the floors, once patients are discharge from the recovery room.  For example, a patient may receive pain medications from multiple sources, with unpredictable onsets.  How do we know their maximum respiratory depression won't happen after they've been delivered to their hospital room?

A patient can receive oxycontin and celebrex orally from a surgeon before their knee replacement surgery, then more fentanyl, morphine, and versed from us (anesthesia).  The surgeon may then inject bupivicaine and morphine into the joint at the conclusion of surgery (without necessarily telling the anesthesiologist). I might also do a femoral nerve block to further reduce post-op pain.  All of us are trying to do right by the patient but, given the right set of circumstances, are setting them up for significant respiratory depression post-op.  The ability to reliably monitor respiratory rate with this new Masimo monitor would be a huge patient safety advance.

The Society for Technology in Anesthesia abstract is here.

March 30, 1842: The First Ether Anesthetic

• Categories: Anesthesia practice
• Printer Friendly|#| Trackback

Wikipedia

CRNA Independent Practice: Deciding Which Question to Answer

• Categories: Politics, Anesthesia practice
• Printer Friendly|#| Trackback

In doing some more reading on the CRNA independent practice issue, I found what I thought was a curious quote in a Centers for Medicare and Medicaid Services press release from January 17, 2001. The press release is an announcement that Medicare will leave decisions on whether physician supervision of CRNA's is necessary to the States. Here's the quote from the second to the last paragraph:

I think asserting that there is no evidence that CRNA independent practice would cause adverse outcome is the wrong question to address. I think the question should be, 'is there evidence that CRNA independent practice would be as safe for patients as the present system?' (we're a six sigma specialty, remember).

The Safe Seniors Assurance Study Act of 1999 was to address the issue but it never made it out of committee:

Sounds like a good starting point for this discussion, however...

(Another Reason Why) I Like Desflurane

• Categories: Technology, Anesthesia practice, Medical errors
• Printer Friendly|#| Trackback

I've posted before on why I think the desflurane Tec 6 vaporizer is a good design (it doesn't need to be turned off to be refilled). I'd like to add another reason to the list: it has alarms.

The Desflurane Tec 6 has a 'low agent' alarm and a 'no output' alarm, in addition to the ability to detect when it has been tipped (and therefore shouldn't be used). The other common agent, Sevoflurane, is delivered via a vaporizer that has none of these things. I am personally aware of two cases where no volatile anesthetic was delivered despite the vaporizer being 'open'. Two cases that would have been uneventful if desflurane and a Tec 6 vaporizer had been used. I'm going to ask the Society for Technology in Anesthesia listserv if there is any reason the Sevoflurane vaporizer couldn't have these features.

Keeping Patients Warm Means Generating Heat

• Categories: Medical Articles, Anesthesia practice
• Printer Friendly|#| Trackback

Once anesthetized with a general anesthetic, patients are largely defenseless. The anesthesiologist is responsible for protecting the patient from their environment--an environment that can be increasingly hostile. One key facet of that environment is temperature, but control of it has never been more contested in the operating room than it is today.

My perspective may be skewed because I do so much anesthesia for orthopedic surgery--a surgery in which the surgeon is physically working hard under an OR gown, gloves, and hot lights. Certainly in pediatric rooms no one ever complains during times when we make the room hot. That's not true, actually. They complain, but they know full well that we are all there to keep the pediatric patient safe and keeping them warm is part of that. They don't expect us to drop the room temperature until we have the child anesthetized and covered.

But why does room temperature matter? It matters because it can affect patient body temperature, and patient body temperature matters for the following reasons:

1. Mild hypothermia (1-3 deg. C) reduces resistance to surgical wound infection.
2. Mild hypothermia prolongs hospital stay.
3. Even mild hypothermia can cause shivering and be a very uncomfortable feeling after surgery.
4. Shivering increases stress on the heart. In patients with heart disease this may cause ischemia.

Under anesthesia, our normal mechanisms for keeping warm are limited. Anesthetics significantly impair our ability to control blood flow to the skin. Although there are five mechanisms of heat loss from the body in the operating room, 90 percent occurs through the skin via radiation and convection

For those wanting a detailed review article and that have a NEJM subscription, see: Mild Perioperative Hypothermia by Daniel Sessler, M.D. in the Department of Anesthesia at UCSF.

I'm sure patients would be gratified to know that it's not the person with the most knowledge and training in patient temperature management that decides in most cases, but the person that whines the most (or is the sneakiest).

For example, last year I was scheduled to provide anesthesia for a 16 year old athlete having an ACL reconstruction. This was not the first case in that room, so the room was already as cold as a meat locker--64 degrees. I reset the room thermostat to 72 degrees, and placed a sticky note saying 'Please Do Not Change,' printed my name, and went to go see the patient.

When I came back to the room several minutes later, the note was gone and thermostat reset to 64 degrees. I replaced the note and reset the thermostat two more times. Both times the note was gone and thermostat reset. The final time there was a note from the charge nurse asking me to come see her.

What did I do? I did what any self-respecting anesthesiologist would do--I told the OR nurses the case was on hold until the room temperature came up and went to get some coffee. Not long after that the charge nurse paged me to discuss the issue. (Nothing gets management's attention more than a case delay.)

Why had she reset it? Because, she claimed, biomedical engineering (some guy with a Bachelor's Degree) said that bringing surgical instruments into a 72 degree room would cause them to sweat and possibly impair sterility. I thought back to my years of doing anesthesia for burn surgery in 85 degree operating rooms and found this explanation novel and fascinating. 'So', I asked her, 'you're taking the advice of a four year college graduate over that of a board certified anesthesiologist?'

Well, you can guess how the conversation went after that. These days, if someone in the OR is feeling hot they either turn the thermostat down themselves or ask the circulating nurse to do it. If all this done without asking me when I'm in the room, I point out to them that they should have asked me before making that decision and ask instead that the room temperature be increased several degrees. If they do ask me if they can turn the room temperature down, provided the patient is reasonably warm and covered, I'll oblige and say 'Thank for asking me. The patient appreciates it. You may set the room temperature to whatever you like.'

In days past everyone acknowledged room temperature was the anesthesiologists choice. These days I have to fight to control it, as I do for every other shred of professional respect. What I'm working on is to get a ruling from the OR committee that states room temperature is my bailiwick. With impending pay for performance measures that will include patient temperature on arrival to the recovery room, this issue has been forced to a head.

Status Report on Google Modules

• Categories: Anesthesia practice, Web Sites
• Printer Friendly|#| Trackback

A while ago Seth Dillingham wrote two Google modules for me: Allowable Blood Loss and BMI Calculator. Well, I still have a hard time finding them on Googles own module site, but I can find them both on googlemodules.com--the 'Unofficial Google Modules Site'.

I wanted to pass along another use for the allowable blood loss calculator--estimating surgical blood loss. Anesthetists are asked to estimate the volume of surgical blood loss that occurs during a procedure on their anesthetic record. Surgeons will often attempt to influence that figure downward by volunteering their own estimate of blood loss (often not grounded in reality) in the hope of getting me to go along with it.

In large blood loss cases where I've been following the hematocrit I use the formula to calculate the actual blood loss. For example, if a 100 kg male started with a hematocrit of 0.40 and wound up with a hematocrit of 0.32 I calculate their blood loss as 1600 cc. No arguments.

Wet taps and the number '3'

• Categories: Anesthesia practice
• Printer Friendly|#| Trackback

Wet taps are accidental dural punctures that happen while attempting to place a needle into the epidural space. The published frequency of wet taps is about 1 in 800 epidural placements, depending on the experience of the operator. If I'm placing an epidural catheter in a pregnant woman and get a wet tap, she has a greater than 50% chance of a dural puncture headache (unless, of course, she is morbidly obese, in which her risk is almost zero).

It seems my wet taps come in three's (hence the title of this post). I remember as a third year anesthesiology resident being on call on OB for the first time after spending three months on the transplant anesthesia service and getting three consecutive wet taps that night on OB. Bam, bam, bam (or should I say 'splash, splash, splash'). I felt terrible, of course, but could not recall doing anything different that would have caused them! My grandmother used to say that accidents happen in threes. She was referring to airplane crashes, but I have to wonder, is it true of wet taps?

In the last ten years of doing anesthesia I've had no accidental dural punctures that I know of. That all changed about a month ago. I did a lumbar epidural steroid injection on a co-worker's husband and must have scored the dura. That's one. I had a wet tap during a labor epidural on a patient who, in retrospect, had a non-union of the ligamentum flavum. That's two. I'm just waiting for number three. I'm on call on OB tonight. Is number three around the corner?

[here's a nice review, btw]

Smoking Cessation Before Surgery Encouraged

• Categories: Medical Articles, Anesthesia practice
• Printer Friendly|#| Trackback

I think this is noteworthy because, in terms of complications, we used to think that one would need to quit smoking for at least six weeks before surgery for there to be any benefit. Though that may still be true, this review seems to indicate that if someone were to quit around time of surgery, their chances of success are better.

[via Newswise]

Are Lower Back Tattoos A Contraindication To Labor Epidurals?

• Categories: News, Anesthesia practice
• Printer Friendly|#| Trackback

My Google News section on 'epidurals' came up with an interesting hit: Lower-back tattoos are popular with women, but do they make having epidurals during childbirth more dangerous?. It's a very good question because, at least in my practice, lower back tattoos are extremely common in laboring women. So common, in fact, that Saturday Night Live has a commercial parody for a product called Turlington's Lower Back Tattoo Remover (quicktime | windows media).

I was taught to avoid putting an epidural needle through tattooed skin and have gone to great lengths to do so. For example, one patient had a very large tattoo of what appeared to be the face of the devil on her lower back. On closer inspection, I noticed that the devil's right nares (which was free of tattoo ink) was right over her L3-4 interspace. I wished I'd taken a picture of that epidural catheter snaking out of the devil's nose.

I can't seem to find much science on the subject save for one abstract which makes a very reasonable suggestion to avoid coring out tattooed skin by making a small incision, if necessary. This may sound like a lot of trouble, but all it takes is a 16 gauge (or similarly large) hypodermic needle inserted into the skin first, then the epidural needle through that 'incision'.

Or Their Designee...

• Categories: Anesthesia practice
• Printer Friendly|#| Trackback

If you read your consent for surgery, you'll see those words right after your surgeon's name. Maybe you've noticed them. Probably you haven't.

Ghost surgery is defined as "substitution of an authorized surgeon by an unauthorized surgeon or the allowance of unauthorized surgical trainees to operate without adequate supervision". Now, that definition is sufficiently vague to allow all manner of stuff to go on, but I would wager that if you asked the patient wether they were under the impression their surgeon would do the entire surgery, that they would say 'yes.' If I ask surgeon W to do my surgery, I'd like surgeon W to sew the skin closed, too. Residents can practice closing just fine in partial-task simulators.

Medpundit Looks At His Financials

• Categories: Health Care Finance, Anesthesia practice
• Printer Friendly|#| Trackback

Ugh: I just spent the better part of the afternoon...: