Facts of Sedation & GA for Dental Treatment
Dental treatment is been related to phobia, anxiety and fear of complications in the minds of patients. No doubt there are real clinical situations requiring modality more than use of local anesthesia to relieve pain while dental treatment. But, in the recent past nitrous oxide-oxygen sedation and other form of sedation for dental treatment has become more of marketing gimmick than actual need.
- A fearful, anxious, or obstreperous patient
- Patients with special health care needs
- Patients with uncontrolled gag reflex
- Patients in whom local anesthesia cannot be used
- Chronic obstructive pulmonary diseases
- Severe emotional disturbances or drug-related dependencies
- First trimester of pregnancy
- Treatment with bleomycin sulfate
- Methylenetetrahydrofolate reductase deficiency
Nitrous oxide-oxygen sedation through nasal attachment.
The machine delivers nitrous oxide-oxygen in the ratio 70:30. Many safety features are included in the apparatus like minimum 30% of oxygen is ensured, if the oxygen is supply is reduced the nitrous oxide supply is cut off.
Are we prepared?
Are we prepared to use or suggest in the clinic for actual situations requiring sedation? We need to understand thoroughly the anatomy, physiology, pharmacology and therapeutics of the modality to render the treatment.
- Most situations requiring sedation in dentistry are kids
- Our work area is mouth
- We are sharing the area with airway for sedation or oxygenation
- The airway becomes more important when the patient is sedated, semi-conscious or in GA
Stages of Anesthesia:
Stage I (analgesia) represents a patient in a relaxed and comfortable state. Pain is diminished to varying extents; fear/anxiety is reduced.
Stage II (excitement) occurs as CNS depression deepens. The excitement /delirium stage often presents with the patient becoming combative and over-reactive.
Stage III (anesthesia) occurs if CNS depression continues the stage used for major surgical procedures.
Stage IV (depression) involves deeper depression, resulting in medullary paralysis/death.
We must understand the stages of anesthesia depend upon the concentration of the drug delivered. So, if we are using sedation with these drugs, we must also be prepared for general anesthesia. This part of the preparation may be overlooked while taking up procedure on OPD basis and in dental clinical set up.
Anesthetic risk may be defined as the chance or probability of untoward consequence in the perioperative period as a result of anesthetic.
Factors for untoward consequence depend upon
- Condition of the patient
- Operation and
- The Anesthesia.
So, we must keep in mind that we are adding one more risk factor for the procedure, which is anesthesia.
Complications of anesthesia:
- Respiratory depression
- Cardiac arrhythmias
- Sore throat
- Hoarseness of voice
- Nerve palsies
- Prolonged anesthesia
Process of Anesthesia:
Following steps involves the process of anesthesia which are carried out by the anesthesiologist. So, the systematic evaluation of the patient needs to be completed well before the procedure.
- Preanaesthetic evaluation
We must also understand the anatomy of the airway as the inhalation sedation is delivered through naso-pharyngeal airway. There are certain differences in the airway when child patient is being treated.
In sedation or semi-conscious patient airway may be obstructed at oro-pharyngeal region.
Positioning the patient with head tilt, chin lift and jaw thrust manure can open the airway at the pharyngeal region.
Mallapati classification of Airway:
Assessment is carried out by the competent anesthetist as a part of pre-anesthetic evaluation. Brief description is as follows.
Class I: 1. Soft palate, fauces, uvula
2. laryngoscopic view: entire glottis
Class II: 1. Soft palate, fauces, uvula
2. Posterior commissure
Class III: 1. Soft palate, uvula base
2. Tip of epiglottis
Class IV: 1. Hard palate only
2. No glottal structure
Adult Vs Child Airway:
- After about 8 years of age airway difference between adults and children mainly reflect size differences.
- Large head
- Disproportionately large tongue as compared to adult
- Larynx is more cephalid infants as the cricoid cartilage is opposite the fourth cervical vertebra
- Epiglottis is longer and stiffer and lies more horizontal
- Cricoid cartilage is the narrowest point of airway until about 8 years, shorter trachea, the angles of male bronchi make equal deviation.
- For difficult airway variety of laryngoscopes and special blades, stylets, light wands, LMA, flexible fiber optic bronchoscope would require.
- Special situation in Cleft lip, alveolus and palate &
The patency of airway becomes added risk with enlarged adenoids and tonsils especially in children.
If we are inclined to carry out sedation for dental treatment in the dental clinic, following facilities need to be made available.
- Pre-operative & Recovery area
- Oxygen source
- Anesthesia machine
- Airway gadgets
- IV Line
- Trained nurses and assistants
Advantages Vs risk:
The area of operation becomes same for both the anesthetist and the dental surgeon as the sedation drugs and oxygen are delivered through nose. In sedation breathing is maintained by the patient, and it is spontaneous like when you are in sleep. So the oral reflexes may be diminished and anything falling in the throat can be easily aspirated.
Note that the anesthetist and the dental surgeon are working in the same area
Expertise & Equipments:
- We must understand the pharmacology & stages for sedation, analgesia & anesthesia.
- As a dentist are we trained to do it ourselves? The answer would be no. The procedure must be carried out by the anesthetist while we carry out the dental treatments.
- Can we do it OPD basis? Yes, but all the pre-operative pre-medications & protocols must be followed both by the dental surgeon and the patient.
- Pre-operative room, operative area & recovery room and facilities are required at dental clinic.
- Expert anesthesiologist & nurse who are well versed with dental procedures should be taken as team.
- Prepare to manage untoward incidences
General Anesthesia (GA) Vs Sedation:
- Patient is in complete anesthesia, so there is complete control and accessibility for the procedure.
- Naso-endotracheal tube will be in position, so oxygenation and drug delivery will be smooth.
- The Naso-endotracheal tube can be positioned according to the convenience on the head end or on the lateral side.
- Throat pack around the endotracheal tube ensures aspiration any foreign body.
- Muscle relaxant drugs are used which can help in adequate mouth opening.
- Skilled anesthetist & assistants make sure we concentrate on dental procedure.
- Thus, we can minimize the risk of the procedure by preparing the patient for GA and ensuring smooth recovery.
Dental Treatment in OT (operation theatre) at Hospital:
Thus, it is recommended to carry out dental treatments in patients requiring sedation or GA at hospital operation theatre rather than in the dental clinical set up.
With the availability of advanced dental equipment like, portable dental turbine for airotor and three way syringe, hand held intra-oral x-ray, RVG, endomotors, apex locaters and any other dental cements and materials, we can arrange and carry out all the required dental treatment in OT.
Well versed anesthetist can take care of the sedation or GA and recovery while dental surgeons can concentrate on the dental treatment.
- Patient needs to be hospitalized one day prior to the procedure
- Pre-anesthetic evaluation and pre-anesthetic protocols and pre-medications to be followed as per the anesthetist
- Plan for comprehensive dental treatment
- Plan and complete all treatment in one go
- Use of quality & durable materials
- Required equipment should be arranged in the OT
- We have situations & need for sedation/GA for dental treatment
- Discuss to the patient & make them understand
- Include trained anesthetist for our requirement for the procedure
- Arrange equipment in the hospital OT
- Prepare to avoid complications &
- Manage efficiently & uphold the dental profession in medical field