Introduction:
Anesthesia suppresses pain and other senses during surgery or other medical interventions by administering anesthetics. Anesthetics are either injected into the patient or made to inhale through masks. The patient cannot be aroused to command, touch, and have painful sensations. Because of upper airway blockage, some sort of intervention, generally the insertion of a laryngeal mask airway or an endotracheal tube, is usually required to preserve respiratory function. Spontaneous ventilation is typically insufficient, requiring partial or complete mechanical assistance using positive pressure ventilation. The cardiovascular function could be compromised, resulting in hypotension and dysrhythmias.
When the physical examination was the only way to determine a patient's level of anesthesia, an overdose of the anesthetic by an untrained anesthetist was common. The anesthetic community formulated a proper systematic strategy for monitoring the overdose of anesthetic agents in the twentieth century. Finally, in the twentieth century, Dr. Arthur Guedel developed one of the initial safety protocols in anesthesiology in 1937, with a chart explaining the anesthesia stages in increasing depth from stage one to stage four. Even though improved anesthetic medicines and delivery mechanisms have resulted in rapid onset and recovery from general anesthesia (in some circumstances, altogether avoiding some stages), Guedel's categorization is still utilized nowadays.
What Is the Primary Goal of Anesthesia?
The primary goal is to produce unconsciousness, forgetfulness, insensibility to pain, skeletal muscle relaxation of the skeletal muscle, and the loss of autonomic system responses. Many drugs may be administered intravenously or inhaled.
What Are the Stages of Anesthesia?
1. Stage 1 (Analgesia or Disorientation): This stage can commence in a preoperative anesthesiology waiting room when the patient is administered drugs and may feel its effects while still conscious. Patients are sedated and conversant during this period, sometimes called the ‘induction stage.’ Breathing is slow and consistent. The patient advances from losing the ability to feel pain (analgesia without memory loss) to analgesia with concurrent amnesia. This stage concludes with a loss of consciousness.
2. Stage 2 (Excitement or Delirium): This stage is characterized by disinhibition, delirium (loss of memory), unrestrained movements, lack of eyelash response, high blood pressure, and increased heart rate. During this period, airway reflexes remain constant and frequently respond to stimuli. Airway manipulation, including the insertion and removal of endotracheal tubes and deep suctioning techniques, should be prevented during this period of anesthesia. At this point, there is a greater risk of laryngospasm (involuntary tonic closure of the vocal cords), which any airway intervention can exacerbate. As a result, spastic movements, gag reflexes, and quick, irregular respiratory rate might endanger the patient's airway. Fast-acting medications assist the time spend in stage two as much as possible and ease entrance into stage three.
3. Stage 3 (Surgical Anesthesia): This is the anesthetic level employed for general anesthesia operations. Sluggish eye movements and respiratory distress distinguish this stage. This stage is divided into four ‘planes.’
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Plane 1: Has continuous respiration, constricted pupils, and center gaze. Furthermore, eyelid, conjunctival, and swallow reflexes frequently vanish at this level. During
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Plane 2: Periodic breathing cessations and loss of corneal and laryngeal reflexes. It may restrict eye movement, and lacrimation may increase.
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Plane 3: Is distinguished by total relaxation of the abdominal and intercostal muscles and the absence of the pupillary light reflexes. Since it is excellent for most procedures, this plane is called ‘real surgical anesthesia.’
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Plane 4: Is distinguished by irregular breathing, paradoxical rib cage movement, and paralysis of the complete diaphragm, which results in apnea (temporary stoppage in breathing).
4. Stage 4 (Overdose): This stage begins when anesthetic medications are administered over the amount of surgical stimulation, resulting in a deterioration of a previously severe brain or medullary depression. This phase commences with respiratory failure and concludes with death. At this stage, skeletal muscles are weak and soft, and pupils are fixed and dilated. In addition, blood pressure is frequently much lower than usual, with weak and thready pulses due to cardiac pump suppression and vasodilation in the peripheral circulation. This stage is fatal without circulatory and respiratory assistance. As a result, the anesthetist's objective is to move the patient to stage three anesthesia as quickly as possible and maintain patients in stage three throughout the procedure.
What Are the Problems to Be Addressed?
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When emergency conditions are not effectively treated, general anesthesia generates physiological reactions that can result in morbidity and death.
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As a result, it is considered a high-risk activity during which the advantages of surgery must surpass the risks.
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Although death from anesthetic treatment is uncommon, it can occur due to pulmonary aspiration of stomach contents, suffocation, or allergy.
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These adverse outcomes might occur due to anesthesia-related device failure or, more frequently, human mistakes.
What Is the Clinical Significance?
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Guedel's classifications for the phases of general anesthesia were developed to deliver diethyl ether, the only volatile anesthetic available at that period. Gaudel premedicated the patients with sedatives like Morphine, Atropine, and Ether for induction.
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Since it provides the loss of pain and memory and muscular relaxation, by the 1980s, Ether had been phased out and replaced with modern fluorinated hydrocarbon anesthetics.
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Currently, the ‘balanced anesthesia’ technique employs a variety of medicines for induction (including injectable anesthetic drugs, analgesics, neuromuscular blockers, and benzodiazepines), which can camouflage the clinical indicators associated with each specified anesthesia stage. These agents are also less dangerous than diethyl ether.
Conclusion:
To ensure patient safety, anesthesia is best conducted through a multidisciplinary strategy involving anesthesiologists and certified registered anesthetist nurses, other operating room staff, recovery room staff, and anesthesia technicians. Because there is no drug capable of rapidly reversing the effects of inhaled anesthetics, the patient must be closely monitored during anesthesia. During the induction and maintenance phases, a qualified anesthesiologist or nurse should closely examine vital signs to ensure that the patient is suitably sedated and shows no symptoms of instability. Every hospital operating room, outpatient surgery or treatment facility, and office-based environment must follow standard norms and procedures for monitoring the patient under anesthesia.
