
An acceleromyograph is a
piezoelectric
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word ' ...
myograph, used to measure the force produced by a
muscle
Skeletal muscles (commonly referred to as muscles) are Organ (biology), organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other ...
after it has undergone nerve stimulation. Acceleromyographs may be used, during anaesthesia when muscle relaxants are administered, to measure the depth of neuromuscular blockade and to assess adequacy of recovery from these agents at the end of surgery. Acceleromyography is classified as quantitative
neuromuscular monitoring In anesthesia, neuromuscular blocking agents may be required to facilitate endotracheal intubation and provide optimal surgical conditions. When neuromuscular blocking agents are administered, neuromuscular function of the patient must be monitored ...
.
Rationale
Patients who undergo anesthesia may receive a drug that
paralyzes muscles, facilitating endotracheal intubation and improving operating conditions for the surgeon. Longer-acting drugs have higher prevalence of residual blockade in the
PACU
Pacu () is a common name used to refer to several species of omnivorous South American freshwater serrasalmid fish that are related to the piranha. Pacu and piranha do not have similar teeth, the main difference being jaw alignment; piranha ha ...
or
ICU
ICU commonly refers to:
* Intensive care unit, a special department of a hospital
ICU may also refer to:
Organisations Universities
* Information and Communications University, South Korea
*Istanbul Commerce University, Istanbul, Turkey
* Intern ...
than shorter acting drugs. Different clinical tests to measure or exclude evidence of residual
muscle weakness
Muscle weakness is a lack of muscle strength. Its causes are many and can be divided into conditions that have either true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, includi ...
have been described but cannot exclude
postoperative residual curarization
Postoperative residual curarization (PORC) or residual neuromuscular blockade (RNMB) is a residual paresis after emergence from general anesthesia that may occur with the use of neuromuscular-blocking drugs. Today residual neuromuscular blockad ...
.
Small degrees of muscle blockade can only accurately be measured by the use of quantitative neuromuscular monitoring. Specifically, the observer cannot reliably measure muscular fade when
train-of-four ratios are between 0.4 and 0.9.
Acceleromyograph design
Acceleromyographs measure muscle activity using a miniature
piezoelectric transducer
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word ''p ...
that is attached to the stimulated muscle. A voltage is created when the muscle accelerates and that acceleration is proportion to force of contraction. The mass of the piezoelectric transducer is known and the acceleration is measured therefore the force can be calculated, (
Force
In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a ...
=
mass
Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different element ...
×
acceleration
In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by ...
). Acceleromyographs are more costly than the more common twitch monitors, but have been shown to better alleviate residual blockade and associated symptoms of muscle weakness, and to improve overall quality of recovery.
See also
*
Muscle relaxant
A muscle relaxant is a drug that affects skeletal muscle function and decreases the muscle tone. It may be used to alleviate symptoms such as muscle spasms, pain, and hyperreflexia. The term "muscle relaxant" is used to refer to two major therape ...
*
Myograph
*
Neuromuscular-blocking drug
Neuromuscular-blocking drugs block neuromuscular transmission at the neuromuscular junction, causing paralysis of the affected skeletal muscles. This is accomplished via their action on the post-synaptic acetylcholine (Nm) receptors.
In cli ...
*
Neuromuscular monitoring In anesthesia, neuromuscular blocking agents may be required to facilitate endotracheal intubation and provide optimal surgical conditions. When neuromuscular blocking agents are administered, neuromuscular function of the patient must be monitored ...
References
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External links
Comparison of mechanomyography and acceleromyography in myotonic dystrophy type 1at Respond2Articles.com
Anesthesia
Muscular system
Medical devices