Premedication: targeting pain components
For adequate patient protection prior to the procedure, the main components of the pain response must be suppressed:
- Sensory component: eliminated by nonsteroidal anti-inflammatory drugs and non-opioid analgesics. Potent opioid drugs are generally not advisable in routine practice.
- Autonomic component: requires stabilization depending on the patient's status. In sympathoadrenal reactions (fear causing tachycardia and hypertension), vasodilators or antihypertensive agents are prescribed. In case of increased vagal tone, which threatens bradycardia and fainting, anticholinergics (atropine) are used.
- Motor component: muscle relaxation is achieved indirectly, mainly by benzodiazepine tranquilizers, which relieve psycho-emotional tension.
General anesthesia and its types
General anesthesia (narcosis) is a state of reversible loss of consciousness with complete amnesia, analgesia, and muscle relaxation. In maxillofacial surgery, the following are used:
- Endotracheal anesthesia: restricted to the hospital setting for extensive surgeries, high risk of airway obstruction, or aspiration.
- Inhalation anesthesia: gases or vapors diffuse from the alveoli into the blood (e.g., nitrous oxide, halothane, sevoflurane).
- Non-inhalation anesthesia: drugs are administered intravenously (propofol, ketamine), less frequently intramuscularly or via other routes.
Combined protection methods
The modern approach is based on multicomponent techniques, combining different agents for maximum effect and reduced side effects.
- Neuroleptanalgesia (NLA): a combination of a potent analgesic (fentanyl) and a neuroleptic (droperidol). Consciousness is preserved, but the patient is calm, indifferent, and feels no pain.
- Ataralgesia: a variant of NLA where a tranquilizer (e.g., seduxen) is used instead of a neuroleptic. Often supplemented with nitrous oxide to induce loss of consciousness.
- Central analgesia: administration of high doses of opioid analgesics that block pain impulses without inducing full general anesthesia.
Specifics in outpatient dentistry
Performing general anesthesia in an outpatient clinic is associated with risks, primarily due to intraoral manipulations (danger of saliva or blood aspiration). In emergency patients, the factor of incomplete examination is added. Therefore, there are strict absolute indications for general anesthesia:
- Central nervous system diseases with intellectual impairment, making communication with the patient impossible.
- Polyvalent drug allergy that precludes the use of local anesthesia.
Briefly: answers to topical questions
What drugs are used for non-inhalation anesthesia in dentistry?
Several groups of drugs are used for non-inhalation (intravenous) anesthesia in dentistry.
- Ketamine (ketalar, calypsol, ketajest) is used for intravenous and intramuscular anesthesia, successfully utilized in facial and oral cavity surgeries.
- Propofol (diprivan, recofol) is available as an emulsion for intravenous administration.
- Propanidid (sombrevin, epontol) is an ultra-short-acting anesthetic.
- Sodium oxybutyrate (Sodium oxybate, GHB) exerts sedative and narcotic effects, increasing the body's resistance to hypoxia.
- Barbiturates (hexenal, thiopental sodium) retain their value as agents for induction anesthesia.
What are the contraindications to general anesthesia in outpatient dentistry?
Contraindications to anesthesia in outpatient settings include the following conditions and diseases.
- Acute diseases — parenchymal organ pathologies, upper respiratory tract inflammatory diseases, and pneumonia.
- Cardiovascular pathologies — decompensated heart failure, myocardial infarction, and the post-infarction period up to 6 months.
- Endocrine disorders — uncompensated diabetes mellitus, severe thyrotoxicosis, adrenal diseases.
- Other conditions — severe bronchial asthma, pronounced anemia, frequent epileptic seizures, full stomach, prolonged glucocorticoid therapy, as well as acute alcohol or drug intoxication.
What stages are distinguished in the clinical course of classical ether anesthesia?
Four consecutive stages are distinguished in the clinical course of classical ether anesthesia according to Guedel.
- Stage I (Analgesia) — the patient's consciousness is preserved, eyelids are closed.
- Stage II (Excitement) — eyelids are tightly closed, skin color becomes bright red.
- Stage III (Surgical) — the tolerant stage, divided into 4 planes (III-1, III-2, III-3, III-4), characterized by gradual opening of the eyelids and paleness of the skin.
- Stage IV (Awakening) — eyelids are alternately half-open or closed.
Additionally, overdose is distinguished, characterized by widely open eyelids and a pale cyanotic skin shade.
What complications can occur during neuroleptanalgesia?
Sources do not provide a direct list of complications for the neuroleptanalgesia technique itself, but side effects of the drugs used for it (fentanyl and droperidol) are described, which can lead to complications.
- Respiratory depression — caused by both fentanyl and droperidol.
- Cardiovascular disturbances — droperidol lowers blood pressure, weakens myocardial contractility, and may cause tachycardia or bradycardia.
- Suppression of the cough reflex — a side effect of fentanyl.
To memorize types of combined pain relief without loss of consciousness: NLA = Neuroleptic + Analgesic (N+A). Ataralgesia = Tranquilizer + Analgesic (T+A).
Class and exam questions
Why is atropine included in premedication?
Atropine (an anticholinergic) is needed to relieve vagal reactions, prevent bradycardia, and fainting triggered by fear and pain.
What is the essence of neuroleptanalgesia?
Achieving deep pain relief and psychological indifference to the procedure while preserving consciousness. A potent analgesic and neuroleptic are used.
Can endotracheal anesthesia be performed in an outpatient clinic?
No, it is performed strictly in a hospital setting due to the complexity of the procedure and the need for continuous monitoring.
What else to study on this topic
- Mechanism of action and pharmacokinetics of local anesthetics (esters and amides)
- The role of vasoconstrictors in prolonging the action of anesthetics
- Specific complications of local anesthetics
- Features of periodontal local anesthesia techniques
- Instrumentation for intraligamentary and intraseptal anesthesia
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Other topics in "Chapter 4. Anesthesia in Oral Surgery (S.A. Rabinovich, S.T. Sokhov)"
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