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ANESTHESIA - کاربرد بلوک عصبی در جراحی
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کاربرد بلوک عصبی در جراحی

1388/12/2 02:33 ب.ظ

نویسنده : محمد
ارسال شده در: همه چیز در مورد بیهوشی ... ،

چکیده مطلب

Central neuraxial techniques should be the simplest and most effective
applications of regional anesthesia (RA) in the outpatient setting. Both spinal
and epidural anesthesia are 1) more familiar to practitioners than are
peripheral nerve blocks, 2) generally simpler to perform because they do not
require nerve localization techniques, and 3) performed rapidly and without
assistance. Neuraxial techniques are effective for lower abdominal, perineal,
and lower extremity surgery, and are among the best choices for practitioners
who are just starting to incorporate regional techniques in an outpatient
practice. They also provide optimal outcomes in most of the important aspects of
outpatient anesthesia. Patients with neuraxial blocks have lower pain scores on
admission to the postanesthesia care unit (PACU) compared with patients
receiving general anesthesia (GA).1-5 Their frequency of postoperative nausea
and vomiting (PONV) appears to be one third of that after GA.6 Most important,
the frequency of fast-track eligibility is high,1,6,7 and discharge times may be
competitive with even the fastest of general anesthetic techniques if
appropriate drugs and dosages are chosen. Additionally, modern equipment and
drug choices have reduced the side effects that were of previous concern. With
propofol infusions available to provide light but transient sedation, the
objection to being awake has also disappeared, leaving neuraxial techniques a
clearly superior choice.
This chapter focuses on advantages, disadvantages, and practical points of
spinal and epidural anesthesia in the outpatient setting

General considerations

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Advantages

Spinal anesthesia (SA) is one of the simplest and most reliable of RA
techniques. The anatomic landmarks are easily identified. The block can be
performed with minimal discomfort, the end point is unmistakable, and the onset
of anesthesia is more rapid than with any other RA technique. Because of the
rapidity of onset, the block can be performed in the operating room without the
requirement for additional personnel or a block room. The efficient performance
of the block does not add substantially to operating room time any more than the
induction of GA. The onset of the local anesthetic is sufficiently rapid to
attain surgical anesthesia by the time the positioning and preparation of the
patient are completed. A variety of local anesthetic agents are available that
can provide a wide range of duration of surgical anesthesia. The risk of nausea
can be reduced if systemic opioids are avoided. Likewise, nausea/vomiting2,8,9
and residual somnolence associated with general anesthetics or heavy
premedication can be avoided, allowing a rapid return to full alertness in the
discharge area. SA is also a technique with a high degree of patient familiarity
because of its use in obstetrics and thus is more likely to be accepted by many
patient populations. In addition, it generally uses the lowest milligram dose of
local anesthetic and has the least potential for systemic toxicity.
Epidural anesthesia (EA) shares many of the advantages of SA, particularly the
familiarity to the clinician, the simplicity of landmarks, and ease of
performance of the block. It has the additional advantage of allowing a
continuous catheter to be placed in the epidural space, which creates the
potential for tailoring both the height and duration of the block. Although it
is a more flexible technique, this advantage is attained at the price of a
slower onset of surgical anesthesia.
The combination of spinal and epidural (CSE) anesthesia is also a useful
technique in the outpatient setting. The procedure is technically more
challenging; once the epidural space is identified, the spinal needle must be
introduced through the epidural needle and advanced further into the
subarachnoid space. After the spinal anesthetic is injected, the spinal needle
is withdrawn and the epidural catheter is inserted and taped in place. This
technique requires more time and technical skill, but CSE provides the
advantages of the rapid onset and dense block of SA with the flexibility of an
indwelling catheter to allow incremental and repeated injections to achieve the
desired height and duration of surgical anesthesia. This technique has been used
effectively for extracorporeal shockwave lithotripsy procedures, in which the
duration of treatment may be unpredictable. It has also been used for knee
arthroscopies when low doses of SA are used to provide the shorter duration, but
may not always provide reliable height or duration of blockade.10 Although the
technique combines some of the disadvantages of both neuraxial procedures, it
also maximizes the advantages and positive aspects of both SA and EA




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آخرین ویرایش: 1389/03/9 01:53 ب.ظ