1. Epidurals
The term epidural is often short for epidural anesthesia, a form of regional anesthesia involving injection of drugs through a catheter placed into the epidural space. The injection can cause both a loss of sensation (anaesthesia) and a loss of pain (analgesia), by blocking the transmission of signals through nerves in or near the spinal cord.
Injecting medication into the epidural space is primarily performed for analgesia. When a catheter is placed into the epidural space a continuous infusion can be maintained for several days, if needed. Epidural analgesia may be used:
The term epidural is often short for epidural anesthesia, a form of regional anesthesia involving injection of drugs through a catheter placed into the epidural space. The injection can cause both a loss of sensation (anaesthesia) and a loss of pain (analgesia), by blocking the transmission of signals through nerves in or near the spinal cord.
Injecting medication into the epidural space is primarily performed for analgesia. When a catheter is placed into the epidural space a continuous infusion can be maintained for several days, if needed. Epidural analgesia may be used:
·
For analgesia alone,
where surgery is not contemplated. An epidural for pain relief (e.g. in
childbirth) is unlikely to cause loss of muscle power, but is not usually
sufficient for surgery.
·
As an adjunct to
general anaesthesia. The anaesthetist may use epidural analgesia in
addition to general anaesthesia. This may reduce the patient's requirement for
opioid analgesics.
·
As a sole technique
for surgical anaesthesia. Some operations, most frequently Caesarean
section, may be performed using an epidural anaesthetic as the sole technique.
Typically the patient would remain awake during the operation. The dose
required for anaesthesia is much higher than that required for analgesia.
The
epidural space is more difficult and risky to access as one ascends the spine,
so epidural techniques are most suitable for analgesia for the chest, abdomen,
pelvis or legs. They are much less suitable for analgesia for the neck, or arms
and are not possible for the head (since sensory innervation for the head arises
directly from the brain via cranial nerves rather than from the spinal cord via
the epidural space.)
Side effects
In addition to blocking the nerves which carry
pain, local anaesthetic drugs in the epidural space will block other types of
nerves as well, in a dose-dependent manner. Depending on the drug and dose
used, the effects may last only a few minutes or up to several hours. This
results in three main effects:
·
Loss of other
modalities of sensation (including touch, and proprioception)
·
Loss of muscle power
(hence, a risk of falling)
·
Loss of function of
the sympathetic nervous system, which controls blood pressure
Pain nerves are most sensitive to the effects
of the epidural. This means that a good epidural can provide analgesia without
affecting muscle power or other types of sensation. The larger the dose used,
the more likely it is that the side-effects will be problematic.
For example, a laboring woman may have a
continuous epidural during labor that provides good analgesia without impairing
her ability to move around in bed. She requires a Caesarean section, and is
given a large dose of epidural bupivacaine. After a few minutes, she can no
longer move her legs, or feel her abdomen. Her blood pressure is noted to be
lower and she is given an intravenous bolus of ephedrine or phenylephrine
infusion to compensate. During the operation, she feels no pain.
Very large doses of epidural anaesthetic can
cause paralysis of the intercostal muscles and diaphragm (which are responsible
for breathing), and loss of sympathetic function to the heart itself, causing a
profound drop in heart rate and blood pressure. This requires emergency
treatment, and in severe cases may require airway support. This happens because
the epidural is blocking the heart's sympathetic nerves, as well as the phrenic
nerves, which supply the diaphragm.
The sensation of needing to urinate is
diminished, which often requires the placement of a urinary catheter for the
duration of the epidural.
Opioid drugs in very large doses may cause
troublesome itch, and rarely, delayed respiratory depression.
A
patient receiving an epidural for pain relief typically receives a combination
of local anesthetics and opioids. This combination works better than either type
of drug used alone. Common local anesthetics include lidocaine, bupivacaine,
ropivacaine, and chloroprocaine. Common opioids include morphine, fentanyl,
sufentanil, and pethidine (known as meperidine in the U.S.). These are injected
in relatively small doses.
Occasionally
other agents may be used, such as clonidine or ketamine.
3. Spinal analgesia
Commonly called spinal anesthesia or sub-arachnoid block (S.A.B.) is a form of regional anaesthesia involving injection of a local anaesthetic into the cerebrospinal fluid (CSF), generally through a fine needle. The desired effect is to block the transmission of nerve signals to and from the affected area. Sensory signals from the site are blocked, thereby eliminating pain, and motor signals to the area eliminate movement. In effect, the result is total numbness of the area and paralysis. This allows surgical procedures to be performed with little or no sensation whatsoever to the person undergoing the procedure, and provides a still patient or area for the surgeon to work on.
Some
sedation is sometimes provided to help the patient relax and pass the time
during the procedure, but with a successful spinal anaesthetic the surgery can
be performed with the patient wide awake. Spinal anaesthetics are limited to
procedures involving most structures below the upper abdomen.
Complications
·
Spinal shock
·
Cauda equina injury
·
Cardiac arrest
·
Hypothermia
·
Broken needle
·
Bleeding resulting in
hematoma, with or without subsequent neurological sequelae due to compression
of the spinal nerves
·
Infection: immediate
within six hours of the spinl anaesthetic manifesting as meningism or
meningitis or late, at the site of injection, in the form of pus discharge, due
to improper sterilization of the LP set.
Many people hear the word "hypnosis" and think of people acting foolish on stage or on television shows. Hypnosis for childbirth is not like this at all; it is more like a type of meditation. It puts the woman in a very relaxed state, but she is still herself and still very aware of everything that is happening around her and within her body. She is able to take herself out of the relaxed state, or out of hypnosis, any time she wishes, and will never do anything that she doesn't want to do while in a state of hypnosis.
Sweet Pea in the Pod
www.sweetpeainthepod.com
(928)963-1808
Sedona, Arizona
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