Why do nonspecific anesthetics require a combination of effects?
Specifically, why isn't induced unconsciousness good enough? Or why not newly deadening of pain only? And why is muscle paralysis so key in general anesthesia if there is no twinge or consciousness? Thorough and professional explanations to all 3 parts of my question will get best answer.
Answers:
Traditionally, the components of anesthesia include amnesia, analgesia, and sedation. Many relatives would also include immobilization in there.
Immobilization is a practical consideration for the surgeon--you don't want the patient moving around while you are adjectives on him. This can still happen even if the person is asleep. For visceral operations, folks have intrinsic muscle tone that can make working inside of them very difficult. In these cases, a paralytic is positively essential.
The others are largely for patient comfort. Most patients won't want to remember the anxiety they felt perioperatively, or possibly the sensation/pain of someone poking around inside their belly (in case the other components of the anesthesia be inadequate). In addition, sometimes, you can't give enough anesthetics because of the patient's poor form. I recall a case when I was contained by medical school of a young woman who was have heart surgery. She went into PEA on the table while her chest was open. The anesthesiologist have to completely turn off her inhalant, then gave her deeply of benzos to make sure she didn't remember what happened.
Sedation is, again, a patient comfort point. Most patients don't want to be aware of what is going on while the surgeon has their hands inside of them.
Analgesia is important regardless of whether the lenient is asleep. Obviously, if the patient is aware, you don't want them feeling pain. But even if they are asleep, the body still registers distress and you will see effects of adrenergic stimulation such as increased heart rate and blood pressure if you do not provide adequate analgesia. In addition, the analgesia you provide during the case will enjoy a significant impact on how much pain the patient has *after* the suitcase.
grimmy's answer is good.
From a practical standpoint, there are many drugs that COULD be used solely to complete a general anesthetic, but the side effects of using only one make it naive to use it in the dose required to get the job done.
There are times when a single agent IS used - an example is sevoflurane (in oxygen and nitrous oxide) for babies getting ear tubes put surrounded by. I don't even start an IV in those kids - no need to for the 10 minutes that they are out.
To try that for a cholecystectomy would be near impossible, because the abdominal muscle tone would still be too great, and it would be for a time harder (although not impossible) to get the breathing tube in.
Every anesthetic is tailored to the individual patient, taking into rationalization that person's medical history, the procedure, the surgeon's preferences and our own personal preferences. When we mix drugs, we can get the benefits of each while minimizing the side effects. Source(s): I'm an anesthesiologist.
Good question - we don't know the details exactly.
First of adjectives, we put people to sleep (almost always, but with some exceptions) near a drug called propofol. It is a very short acting sedative/hypnotic, whose mechanism of behaviour is not completely understood. It may exert its primary effect by potentiation of the GABA-A receptor, thereby slowing the channel closing time.
Once a patient is asleep, we almost other use inhalation anesthetics to maintain anesthesia. Those include drugs such as sevoflurane, desflurane and isoflurane, which are all halogenated ethers.
Here is an explanation from an anesthesiology journal:
"Inhaled anesthetics conduct yourself in different ways at the level of the central anxious system. They may disrupt normal synaptic transmission by interfering with the release of neurotransmitters from presynaptic boldness terminal (enhance or depress excitatory or inhibitory transmission), by altering the re-uptake of neurotransmitters, by changing the binding of neurotransmitters to the post-synaptic receptor sites, or by influencing the ionic conductance change that follows activation of the post-synaptic receptor by neurotransmitters. Both, pre- and postsynaptic effects have be found.
Direct interaction with the neuronal plasma membrane is very likely, but indirect management via production of a second messenger also remains possible. The high correlation between lipid solubility and anesthetic potency suggests that inhalation anesthetics have a hydrophobic site of action. Inhalation agents may bind to both membrane lipids and proteins. It is at this time not clear which of the different theories are most plausible to be the main mechanism of action of inhalation anesthetics.
The Meyer-Overton supposition describes the correlation between lipid solubility of inhaled anesthetics and MAC and suggests that anesthesia occurs when a sufficient number of inhalation anesthetic molecules dissolve in the lipid cell membrane. The Meyer-Overton rule postulates that the number of molecules dissolved in the lipid cell membrane and not the type of inhalation agent cause anesthesia. Combinations of different inhaled anesthetics may have additive effects at the level of the cell membrane.
However, the Meyer-Overton guess does not describe why anesthesia occurs. Mullins expanded the Meyer-Overton rule by adding the so-called Critical Volume Hypothesis. He stated that the absorption of anesthetic molecules could expand the volume of a hydrophobic region inwardly the cell membrane and subsequently distort channels necessary for sodium ion flux and the development of achievement potentials necessary for synaptic transmission. The fact that anesthesia occur with significant increase in volume of hydrophobic solvents and is reversible by compressing the volume of the expanded hydrophobic region of the cell membrane supports Mullins Critical Volume Hypothesis.
The protein receptor hypothesis postulates that protein receptors in the interior nervous system are responsible for the mechanism of action of inhaled anesthetics. This view is supported by the steep dose response curve for inhaled anesthetics. However, it remains unclear if inhaled agents disrupt ion flow through membrane channels by an indirect action on the lipid membrane, via a second messenger, or by direct and specific binding to rut proteins.
Another theory describes the activation of Gamma-Aminobutyric acid (GABA) receptors by the inhalation anesthetics. Volatile agents may activate GABA channel and hyperpolarize cell membranes. In addition, they may inhibit certain calcium channels and consequently prevent release of neurotransmitters and inhibit glutamate channels. Volatile anesthetics share therefore common cellular appointments with other sedative, hypnotic or analgesic drugs.
Each of the mentioned theories describes a unitary theory of narcosis. They adjectives concentrate more or less on an unique site of action for inhaled anesthetics. The true instrument of action of volatile anesthetics may be a combination of two or more such theories described as multisite action hypothesis."
Neither of the above drugs has anything that reverses them. We dawdle for propofol to be metabolized, and we allow patients to breathe out the gases, which diffuse from brain to blood to exhaled air.
We use a bunch of other drugs in standard anesthesia, including sedatives like midazolam, opiates and non-opiate analgesics, neuromuscular blocking agents, (all of those have reversal drugs) and numerous cardiac medication and antiemetics. Source(s): Med School, anesthesia clinicals.
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Answers:
Traditionally, the components of anesthesia include amnesia, analgesia, and sedation. Many relatives would also include immobilization in there.
Immobilization is a practical consideration for the surgeon--you don't want the patient moving around while you are adjectives on him. This can still happen even if the person is asleep. For visceral operations, folks have intrinsic muscle tone that can make working inside of them very difficult. In these cases, a paralytic is positively essential.
The others are largely for patient comfort. Most patients won't want to remember the anxiety they felt perioperatively, or possibly the sensation/pain of someone poking around inside their belly (in case the other components of the anesthesia be inadequate). In addition, sometimes, you can't give enough anesthetics because of the patient's poor form. I recall a case when I was contained by medical school of a young woman who was have heart surgery. She went into PEA on the table while her chest was open. The anesthesiologist have to completely turn off her inhalant, then gave her deeply of benzos to make sure she didn't remember what happened.
Sedation is, again, a patient comfort point. Most patients don't want to be aware of what is going on while the surgeon has their hands inside of them.
Analgesia is important regardless of whether the lenient is asleep. Obviously, if the patient is aware, you don't want them feeling pain. But even if they are asleep, the body still registers distress and you will see effects of adrenergic stimulation such as increased heart rate and blood pressure if you do not provide adequate analgesia. In addition, the analgesia you provide during the case will enjoy a significant impact on how much pain the patient has *after* the suitcase.
grimmy's answer is good.
From a practical standpoint, there are many drugs that COULD be used solely to complete a general anesthetic, but the side effects of using only one make it naive to use it in the dose required to get the job done.
There are times when a single agent IS used - an example is sevoflurane (in oxygen and nitrous oxide) for babies getting ear tubes put surrounded by. I don't even start an IV in those kids - no need to for the 10 minutes that they are out.
To try that for a cholecystectomy would be near impossible, because the abdominal muscle tone would still be too great, and it would be for a time harder (although not impossible) to get the breathing tube in.
Every anesthetic is tailored to the individual patient, taking into rationalization that person's medical history, the procedure, the surgeon's preferences and our own personal preferences. When we mix drugs, we can get the benefits of each while minimizing the side effects. Source(s): I'm an anesthesiologist.
Good question - we don't know the details exactly.
First of adjectives, we put people to sleep (almost always, but with some exceptions) near a drug called propofol. It is a very short acting sedative/hypnotic, whose mechanism of behaviour is not completely understood. It may exert its primary effect by potentiation of the GABA-A receptor, thereby slowing the channel closing time.
Once a patient is asleep, we almost other use inhalation anesthetics to maintain anesthesia. Those include drugs such as sevoflurane, desflurane and isoflurane, which are all halogenated ethers.
Here is an explanation from an anesthesiology journal:
"Inhaled anesthetics conduct yourself in different ways at the level of the central anxious system. They may disrupt normal synaptic transmission by interfering with the release of neurotransmitters from presynaptic boldness terminal (enhance or depress excitatory or inhibitory transmission), by altering the re-uptake of neurotransmitters, by changing the binding of neurotransmitters to the post-synaptic receptor sites, or by influencing the ionic conductance change that follows activation of the post-synaptic receptor by neurotransmitters. Both, pre- and postsynaptic effects have be found.
Direct interaction with the neuronal plasma membrane is very likely, but indirect management via production of a second messenger also remains possible. The high correlation between lipid solubility and anesthetic potency suggests that inhalation anesthetics have a hydrophobic site of action. Inhalation agents may bind to both membrane lipids and proteins. It is at this time not clear which of the different theories are most plausible to be the main mechanism of action of inhalation anesthetics.
The Meyer-Overton supposition describes the correlation between lipid solubility of inhaled anesthetics and MAC and suggests that anesthesia occurs when a sufficient number of inhalation anesthetic molecules dissolve in the lipid cell membrane. The Meyer-Overton rule postulates that the number of molecules dissolved in the lipid cell membrane and not the type of inhalation agent cause anesthesia. Combinations of different inhaled anesthetics may have additive effects at the level of the cell membrane.
However, the Meyer-Overton guess does not describe why anesthesia occurs. Mullins expanded the Meyer-Overton rule by adding the so-called Critical Volume Hypothesis. He stated that the absorption of anesthetic molecules could expand the volume of a hydrophobic region inwardly the cell membrane and subsequently distort channels necessary for sodium ion flux and the development of achievement potentials necessary for synaptic transmission. The fact that anesthesia occur with significant increase in volume of hydrophobic solvents and is reversible by compressing the volume of the expanded hydrophobic region of the cell membrane supports Mullins Critical Volume Hypothesis.
The protein receptor hypothesis postulates that protein receptors in the interior nervous system are responsible for the mechanism of action of inhaled anesthetics. This view is supported by the steep dose response curve for inhaled anesthetics. However, it remains unclear if inhaled agents disrupt ion flow through membrane channels by an indirect action on the lipid membrane, via a second messenger, or by direct and specific binding to rut proteins.
Another theory describes the activation of Gamma-Aminobutyric acid (GABA) receptors by the inhalation anesthetics. Volatile agents may activate GABA channel and hyperpolarize cell membranes. In addition, they may inhibit certain calcium channels and consequently prevent release of neurotransmitters and inhibit glutamate channels. Volatile anesthetics share therefore common cellular appointments with other sedative, hypnotic or analgesic drugs.
Each of the mentioned theories describes a unitary theory of narcosis. They adjectives concentrate more or less on an unique site of action for inhaled anesthetics. The true instrument of action of volatile anesthetics may be a combination of two or more such theories described as multisite action hypothesis."
Neither of the above drugs has anything that reverses them. We dawdle for propofol to be metabolized, and we allow patients to breathe out the gases, which diffuse from brain to blood to exhaled air.
We use a bunch of other drugs in standard anesthesia, including sedatives like midazolam, opiates and non-opiate analgesics, neuromuscular blocking agents, (all of those have reversal drugs) and numerous cardiac medication and antiemetics. Source(s): Med School, anesthesia clinicals.
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