Introduction
Anesthesia is used to block the pain sensation going to the brain through nerve conduction. It is used in many surgeries to control pain during and after surgery and is delivered in various modes. Anesthesia comprises four types: general, local, regional anesthesia, and sedation.
What Is Anesthesia?
Anesthesia is a medicine used to control the patient's pain before undergoing a surgery. It is delivered so that the patient's body becomes numb and no sensation is felt, hence no nerve signals pass to the brain, and the patient does not feel any pain during surgery. It is delivered by various modes like injection or inhaling the gasses through masks or by topically applying anesthesia like a gel or spray.
What Are the Different Types of Anesthesia?
Anesthesia is of four different types. They are:
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General Anesthesia - Anesthesia in which a complete loss of consciousness causes the patient to go to sleep. It is used for head, chest, and abdomen surgeries.
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Regional Anesthesia - Anesthesia that leads the patient to be conscious with loss of sensation in the larger body part requiring surgery, like lower limbs. They are used in cesarean surgeries, to numb the legs, or for knee or hip surgeries.
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Local Anesthesia - Local anesthesia is a method of anesthesia used to numb a small area of the body. It is mainly used in dental procedures, biopsies (samples of tissue used to diagnose a pathology), or eye surgeries. It is the most commonly used anesthesia technique for minor procedures. And it keeps the patient awake numbing the specific site alone.
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Sedation - Sedation delivers anesthetic effects as it causes incomplete loss of consciousness during the surgical procedure and calms down the patient or makes the patient sleep. It is similar to general anesthesia but provides the patient with natural sleep. It can vary from mild to moderate sedation depending on the surgery.
What Is Anesthesia Awareness?
Anesthesia awareness is being conscious during surgery, which occurs in procedures involving general anesthesia administration. General anesthesia is administered to make the patient unconscious during surgery, but, unfortunately, in rare circumstances, it does not work effectively, and the patient, in a deep sleep state, becomes a little aware and can remember the surgical events.
What Happens in Anesthesia Awareness?
When the patient is in anesthesia awareness, the patient can hear the staff's voices, which means the patient's hearing ability is still active despite the administration of the anesthetic agent. Sometimes, the patient can even respond to the pain or other pressure movements felt during the ongoing process. Although the patient cannot respond well enough to the conversations, it can be considered that the patient is not completely asleep after the exception of being in a deep sleep state during the surgery.
What Are the Symptoms of Anesthesia Awareness?
Symptoms of anesthesia awareness are:
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The patient can hear noises.
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The patient can remember the events of the surgery.
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The patient can sense mild pain.
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The patient can feel weakness and muscle paralysis.
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The patient can feel anxiety or helplessness.
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The doctor can observe high blood pressure and heart rate.
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The patient can move.
When Does Anesthesia Awareness Occur?
Anesthesia awareness occurs when -
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Paralytic and Muscle Relaxants Are Used - If the patient is under the influence of a paralytic medicine or muscle relaxant then the chances of developing anesthesia awareness are more. As the anesthesia is making these patients unable to move, speak, blink, or respond to pain. But whether the anesthesia has worked or not is detected after administering anesthesia.
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Light Anesthesia - In some patients, the doctor uses less anesthesia medicine due to their medical conditions, like cardiac disease. The light anesthesia administered can cause consciousness in the patient but benefits with less risk after surgery.
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Doctor Errors - An anesthesiologist is a doctor who specializes in anesthesia; if they use short-acting anesthesia medicine for a lengthy surgical procedure that can wear off soon, the patient can become conscious before the surgery is over. Or due to some other errors like the failure of vaporizers.
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Equipment Failures - If the equipment used to deliver the anesthesia is malfunctioning, it can also mislead the amount of anesthesia used for the surgical procedure on a patient. For example, equipment for the volatile gasses inhalation system is used or for nitrous oxide, if this equipment malfunctions then it can affect the amount of nitrous oxide used in the patient.
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Patient Variations - The patient, can also be one such reason for anesthesia awareness. If the patient is drug tolerant to anesthesia medicine, the doctor needs more than the required dose to make the patient unconscious. Patients with increased tolerance include younger age groups, people who are obese, or tobacco-smoking patients.
What Are the Types of Anesthesia Awareness?
Anesthesia awareness can be -
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When Anesthesia Does Not Work - In this condition, the patient has no anesthesia effect, and the patient has a normal sensation and is wide awake. But the paralyzing effect of the medicine will make the patient unable to alert the doctor about awareness as the patient cannot move and speak. Thus, the patient can hear and can remember the events going on during surgery.
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When Paralytic and Anesthesia Medicine Does Not Work - The paralytic and anesthesia medicines are ineffective in some cases, and the patient is conscious and can move and speak. In these cases, the doctor gets to know that the medicine is ineffective.
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When the Paralytic Medicine Does Not Work - When paralytic medicine stops working, the patient starts moving. Still, the patient is under the effect of anesthesia, so the patient is unaware of the movements they make. But the doctor figures that the patient’s paralytic effect has worn off, and the doctor will inject the anesthetic agent again.
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When the Patient’s Condition Demands Light Anesthesia - When the patient's condition is not suitable for moderate anesthetic doses, the doctor uses less anesthesia to prevent additional risks and complications. The use of less anesthesia causes consciousness and anesthesia awareness.
Who Is at High Risk of Having Anesthesia Awareness?
Anesthesia awareness can occur in any patient. But a few patients encounter the immediate effects of anesthesia awareness. They are:
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Patients with low blood pressure.
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Patients with severe trauma and blood loss.
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Cardiac surgery patients.
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Women who have undergone cesarean sections.
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Patients with lung diseases.
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Alcohol or drug abuse patients.
Is Anesthesia Awareness Common or Rare?
Anesthesia awareness is a rare symptom. It occurs in one or two patients in 1,000, as all the patients do not feel anesthesia awareness during surgery.
Is Conscious Sedation And Anesthesia Awareness Similar?
No, conscious sedation is not anesthesia awareness. As conscious sedation is sedative or anesthesia delivered to induce sleep in a patient, the patient can respond to verbal commands and maintain their airway. In contrast, anesthesia awareness occurs when the patient is delivered with general anesthesia and paralytic drugs, facing drug ineffectiveness, and the patient starts feeling pain and gains consciousness.
Conclusion:
Anesthesia awareness occurs when the patient is awake after the surgical procedure. It can occur for many reasons like a mild dose of anesthesia, doctor or equipment errors, and paralytic drugs used in surgery. It is most prevalent in cardiac surgery, cesarean sections, and drug or alcohol abuse. Aand, anesthesia awareness is not similar to conscious sedation. The doctor (anesthesiologist) has to be very careful while administering the anesthesia and all the aspects have to be watched and then a careful step of anesthesia administration should be performed. And by doing this unwanted complications can be prevented, improving the patient's condition.
