General Anesthesia Indications
Communication difficulties due to patient's age
Extensive surgical procedures, especially those requiring respiratory control
Presence of mental disorder
Inadequate regional anesthesia method in terms of effect and duration
In case of reaction to local anesthetics, general anesthesia is applied.
Although general anesthesia can be administered in different ways, it is most commonly given intravenously and by inhalation.
General anesthesia created with volatile anesthetics, especially diethyl ether, consists of the following stages according to the
Guedel classification:
1. Analgesia phase: It is the period from the induction of anesthesia to the loss of consciousness.
Analgesia occurs first, then amnesia.
2. Excitation phase: It is the phase that lasts from loss of consciousness to regular respiration, and vomiting, breath holding, hiccups, tachycardia and arrhythmias can be seen.
Amnesia and loss of consciousness occur. Respiration is irregular. Inhibitory Golgi 2 neurons in the cerebellum are inhibited.
3. Surgical anesthesia phase: This period from the onset of regular breathing to the cessation of breathing consists of 4 parts.
o From onset of regular breathing to loss of eyeball movement
o From loss of eyeball movements to the onset of intercostal paralysis
o intercostal paralysis from onset to completion
o It is the time from completion of intercostal paralysis to diaphragmatic paralysis.
Anesthesia was fully achieved and superficial reflexes disappeared.
Deep reflexes related to vital functions remain active.
Breathing is automatic and rhythmic.
Blood pressure and heart rate return to normal.
4. Medullary Depression Stage: It lasts from diaphragmatic paralysis to cardiac arrest. Pupils are fully dilated. The vasomotor center and respiratory center are depressed.
The most sensitive area to general anesthetics is the cerebral cortex layer and the dorsal horn of the spinal cord (substantia gelatinosa) analgesia circuit.
Respiratory and vasomotor centers in the medulla oblongata are relatively resistant to general anesthetics; however, they are inhibited at high doses.
General Anesthesia Stages in Terms of Application
Induction
It is the stage of introduction to anesthesia.
Induction can be administered intravenously, by inhalation or intramuscularly.
maintenance
It is the period when anesthesia deepens and stabilizes after induction.
During this period, surgical procedures are performed.
The depth of anesthesia is maintained in accordance with the surgical procedure.
Waking up
It is a critical period in which there is a change of consciousness as in the induction of anesthesia.
Towards the end of the surgical procedure, the dose of anesthetics given is gradually reduced.
The most important problems during awakening are related to breathing.
recovery
Awakening from anesthesia may be delayed due to anesthesia drugs and applications, patient and surgery:
- Residual drug effect (overdose, drug metabolism delay, etc.),
- Anesthesia duration and type
- Prolongation of neuromuscular block (liver and kidney failure, plasma cholinesterase insufficiency, etc.)
- Metabolic-endocrine disorders (hypothyroidism, hypo-hyperglycemia)
- Acid-base and electrolyte balance disorders (hyperphosphatemia, hyponatremia)
- Hypothermia
- Hypo-hypercarbia
Neurological complications (central anticholinergic syndrome, cerebral hypoxia, intracranial hemorrhage, embolism) are the causes that can delay awakening.