Several forces are combining to push more and more procedures to the
office setting, from relatively simple "lump and bump" removal to arthroscopy,
liposuction, abdominoplasty, laparoscopic procedures, and many others.
A key aspect of keeping these procedures safe is administering anesthesia
that provides adequate sedation, pre-empts post-op pain, and causes minimal
postoperative nausea and vomiting (PONV). In this article, we'll present
advice from two experts in office-based anesthesia on what you need to
know to provide safe, effective anesthesia in this special venue.
1. Examine Qualifications
It's crucial to make sure that the professionals who provide your
anesthesia are qualified, familiar with office-based procedures, and able
to handle any emergency, says Marc E. Koch, MD, a New York anesthesiologist
who is co-founder and President of Resource Anesthesiology Associates,
P.C., the largest and one of the first accredited office-based anesthesia
practices.
He feels strongly that an anesthesiologist should administer the anesthesia.
"In a hospital, there are many professionals and resources to assist if
there's a crisis. In an office-based setting, the anesthesia provider
may have to play the role of ad hoc cardiologist, pulmonologist, or internist-this
takes skills that only a doctor is likely to have," he notes.
Dr. Koch suggests enlisting the help of an accredited anesthesiology
group to handle all your anesthesia needs. "The Accreditation Association
for Ambulatory Health Care (AAAHC) has recently started accrediting itinerant
anesthesiologists. The accreditation process includes validating physician
credentials, examining practice administration documentation, evaluating
drug procurement processes, and much more. By choosing a group with AAAHC
accreditation, you can be sure that you're getting the best for your facility
and your patients," he says. "If you can't find an accredited group, make
sure you do thorough due diligence and assess whether the group or individual
meets accreditation standards."
Barry L. Friedberg, MD, a Clinical Instructor in Anesthesia at the University
of Southern California who has provided office-based anesthesia for more
than 2,000 patients since 1992, believes that anesthesia providers who
are sensitive to the unique needs of office-based anesthesia are best.
He recommends making sure that the person administering anesthesia in
your office is licensed to do so by a state organization and possesses
the following four things:
– recent experience administering anesthesia in office cases;
– current ACLS certification;
– current malpractice insur- ance; and
– a current Drug Enforcement Administration certificate.
2. Have Backup Equipment and Drugs Available
If you will be using an itinerant anesthesiologist or anesthetist,
it's crucial to communicate your expectations in terms of equipment and
supplies and determine what he or she will bring and what you will provide.
Even if your anesthesiologist agrees to bring everything, it doesn't hurt
to keep critical equipment and medications on hand.
Ask the anesthesia professional whether he believes an anesthesia machine
is necessary. If your cases do not require nitrous oxide or volatile agents,
the most seasoned office-based anesthesiologists will feel comfortable
with a modest-sized oxygen source and an Ambu-bag, even if the case requires
very deep or unconscious sedation. If the case requires prolonged intubation
with muscle relaxation, you may need some sort of mechanical ventilation,
as well.
3. Use Infusion, not Bolus Induction
Some surgeons believe it's best to put the patient to sleep with a bolus
induction because it's more time efficient. They should understand that
it's safer to "drip the patient to sleep" with an infusion induction,
says Dr. Friedberg. "In office cases, there's no rush to put the patient
to sleep-these aren't cases involving life-threatening emergencies," he
notes. Accor-ding to Dr. Friedberg, a bolus dose is more likely to produce
hypotension and transient apnea. Patients who have had both types of inductions
prefer infusion because of its gentle quality. "They wake up and say,
‘I didn't even recall being put out, and I liked it much better'," he
says. Dr. Friedberg usually administers clonidine (0.2 mg po 30-60 minutes
pre-op) first to decrease anxiety (he says it also mitigates changes in
heart rate and blood pressure, decreases the amount of propofol required,
and cuts down on post-op pain and shivering). He also administers glycopyrrolate
(0.2 mg) in the IV to counteract the tendency of ketamine (one of the
main agents in his technique) to increase oral secretions. He then starts
a propofol infusion (5 mg/ml) at 60-80 gtts/min and preps the patient
with body temperature Betadine (room temp may wake up patients).
4. Consider a BIS Monitor
Both of our experts have tried using a bispectral index (BIS) monitor
in the office based setting. "The BIS is very useful because it allows
you to carefully titrate anesthetics more precisely," says Dr. Koch. Dr.
Friedberg agrees, adding that "the BIS empowers the patient to control
their own anesthetic even though they are not awake to do so verbally."
He also claims that by using the device and clonidine premedication, he's
reduced propofol usage by 30 percent.
"Another big advantage of the BIS is that it helps me calm the surgeon,"
he says. "If the patient moves intraoperatively, I can allay the surgeon's
fears and prove that the patient is truly unconscious and not likely to
have awareness or recall by showing him that the BIS is between 60 and
70."
| Think POSEMD
Dr Koch developed the "POSEMD" mnemonic to provide a checklist for office anesthesia:
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P: |
Positive pressure. This could be anything from an Ambu-bag to a full-fledged anesthesia machine.
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O: |
Oxygen Source. Cylinders come in several sizes, and usually
an "E" tank or smaller or more than adequate. Remember that depending on the procedure, it may not be safe to have oxygen in the room.
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S: |
Suction. Dr. Koch recommends purchasing a motorized device rather than a hand-held one.
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E: |
Emergency Equipment: Always have the equivalent
of a crash cart and resuscitative equipment immediately available.
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M: |
Monitors. Monitoring will depend on the type of anesthesia
you're providing; typical requirements are a non-invasive blood pressure device, pulse oximeter, defibrillator, and EKG
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D:
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Drugs: These may include routine anesthetic medications
such as fentanyl and midazolam and hypnotics such as propofol or methohexital, as well as antibiotics.
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5. Cut Back on Fluids
Hospital-based anesthesia providers routinely administer 500 to 1000 ccs
of IV fluid with their anesthesia to prevent dehydration, especially if
patients are NPO after midnight. This isn't necessary in the office, says
Dr. Friedberg. Office patients are not debilitated, and they tend to be
euvolemic even after fasting. Volume loading just means that the patient
will probably wake up with a full bladder, which may result in a hurried
trip to the bathroom or a wet recovery room bed. Dr. Friedberg typically
administers no more than 200 ccs of fluid (usually Lactated Ringers solution,
which serves as the diluent for the propofol).
6. Evaluate Opioid Use
Both Dr. Friedberg and Dr. Koch recommend using opioids (morphine,
meperidine, hydromorphone, fentanyl, alfentanil, sufentanil, or remifentanil)
sparingly. These drugs may depress ventilatory drive, obligating the anesthesia
provider to administer oxygen (which could be a fire hazard, especially
in the presence of lasers), and also depress laryngeal reflexes, increasing
the risk of aspiration. They also increase the risk of PONV.
Both doctors use different methods to treat PONV. Dr. Koch often relies
on regional blocks to numb the surgical site and cut down on the amount
of IV anesthetic required. He uses narcotics sparingly after pre-treatment
with anti-emetics. He warns that "even with aggressive treatment, the
location of the surgery on the body could instigate PONV." For instance,
surgery performed on or near abdominopelvic organs, or on the eyes, ears,
or nose often instigate nausea, especially in women of childbearing age.
Dr. Friedberg relies primarily on pre-emptive nonopioid analgesia with
tumescent anesthesia, peripheral nerve and/or field blocks given with
propofol and ketamine, room air, and spontaneous ventilation.
Ketamine can't be used alone-in fact, it gained a bad reputation when
it was first introduced because it may cause hallucinations when used
by itself.
"The key is to provide a hypnotic level of propofol before administering
the ketamine to block ketamine-induced hallucinations," says Dr. Friedberg.
His preferred technique is to administer a propofol infusion first, and
when hypnosis is achieved (indicated by a BIS level of 75), he injects
a bolus dose of 50 mg ketamine, which produces a 10 to 20-minute window
of intense analgesia. After two minutes, the surgeon starts the procedure
by injecting local anesthetic (usually lidocaine); if the patient makes
purposeful movements or winces, he administers a second dose of ketamine
(25 to 50 mg; 200 mg is the maximum aggregate dose). He then maintains
the patient on propofol until the procedure ends.
Dr. Friedberg recently published a five-year review of the effects of
this technique on 1,200 patients. Only seven vomited post-op (0.6 percent
PONV). "This is a 15 times better PONV rate than the best published reports
using opioids and two antiemetics," he notes. In his eight years using
this method, he says he has had no hospital admissions for either PONV
or pain.
Propofol may be a more expensive drug, but Dr. Friedberg believes that
the benefits ($12/ampule, generic) are well worth the cost. "This is one
of the best drugs we have in our armamentarium, and there is no excuse
for not using it. No other drug will give you universally happy patients,"
he opines. Also, Dr. Friedberg says that since neither propofol nor ketamine
are triggering agents for malignant hyperthermia, using this method exclusively
can save on the added expense of stocking dantrolene.
If your patients are routinely nauseous after procedures and you suspect
that the anesthesia method is to blame, there is a tactic you can take
to motivate the anesthesiologist to rethink his or her methods, says Dr.
Friedberg. Insist that the anesthesiologist not leave your facility until
the patient is medically cleared for leaving. "This rule provides them
with an added incentive to make sure patients recover quickly," says Dr.
Friedberg. Patients are ready to go home when they are alert, oriented
to people, place, and time, have no severe pain or PONV, and are hemodynamically
stable. Depending on the procedure, acetaminophen, Darvocet, Ultram, or
maybe a final re-injection of local anesthesia will help with pain control.
As technology progresses, surgical techniques become less invasive, and
cost pressures increase, office-based facilities will likely do more and
more outpatient surgery. By making sure your anesthesia providers are
qualified and have the support they need, you'll go a long way toward
ensuring safe, happy patients, efficient surgeons, and a smoothly-running
facility.
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