Conscious issues on sedation

18 October, 2011 / editorial

It is now ten years since the practice of general anaesthesia was stopped in dental practice. I recall at that time I, along with all the other dentists who offered general anaesthesia, wondered how we would cope with the patients who fell into the high anxiety category.

Reflecting back on those days it felt as if it would become very difficult to manage these patients, but we have – well almost.

For dentists practicing sedation, you will no doubt find that midazolam will not work on all patients. The patients that will be problematic are still those in the high anxiety category. It can be extremely stressful for the operator trying to undertake treatment on a patient who is moving about, moaning that they are not sleeping, weeping, and trying to push you away. This is a scenario that all dentists regularly practising sedation will have experienced.

Despite this, the vast majority of these patients will report that, after treatment, they do not remember any part of their treatment. The dose titrated to the patients will typically indicate readings of oxygen saturation levels in the range between 93 and 96, with a pulse rate ranging between 110 and 140 beats per minute. Clearly any attempt to increase the dosage would be fraught with problems.

The patient may still be unmanageable, with an increased risk of suppressing their respiration. Under these circumstances it is unwise to proceed and this is where one has to draw the line. Furthermore, patients requiring larger doses tend to have prolonged recovery periods, which is not desirable in a short-term out-patient setting.

When faced with this situation, the operator has to decide: either abandon the case, or carry on regardless. Proceeding with treatment will result with the practitioner enduring a stressful episode, with the possibility of being unable to complete treatment successfully. This will inevitably result in a prolonged recovery period and trying to pacify a distressed patient. Furthermore, the practitioner is then faced with the prospect of having to explain the patient’s behaviour to their partner or escort, who may be concerned. It is not uncommon for female patients to be weepy following treatment with mascara lines running down their face. This further adds to the escort’s anxiety. All of these factors will further add stress to the clinician.

The above mentioned scenario is based on a patient attending for conservation treatment. The picture is made considerably worse when the patient requires traumatic dental treatment. As you will be aware these patients are phobics and, as such, will inevitably require difficult extractions. Fear has kept this category of patients away from the dental surgery, and their dentition is ruined with widespread rampant caries as a result of very poor oral hygiene, a poor diet and a failure to attend for regular treatment.

I am sure that dentists, who have attempted midazolam sedation on these patients, will be aware that treatment is impossible, when you add this to the list of the stressful behavioural patterns previously mentioned.

In my experience, it is this latter group of patients where midazolam sedation has not been effective in rendering the patient manageable for treatment. Often the treatment may involve multiple difficult extractions, some of which may be very traumatic for the patient. General anaesthesia was a very valuable method of patient management for this category of patient.

Of course, there was always the obvious category of patients where general anaesthesia was the method of choice:

  • IV drug users
  • patients on prolonged medication such as oral benzodiazepines or methadone
  • patients who abuse alcohol
  • patients who smoke drugs
  • medical conditions which may preclude IV sedation in the dental practice. Attempting to sedate these patients with midazolam is futile.

Fortunately, since 2001, a safe alternative method has been found to treat these categories of difficult patients. Propofol was a drug primarily used in hospitals as an intravenous induction agent in general anaesthesia.

However, it was later discovered that by administering this drug in lower doses by an intermittent infusion technique, it had extremely good sedative properties. It is now used worldwide in intensive care units to keep patients sedated for prolonged periods of time. This method of sedation was achieved by the use of computerised delivery apparatus otherwise known as TCI (target controlled infusion).

This method slowly titrates a varying dose of propofol intravenously to the patient as set by the operating clinician. This system has now been translated into the dental practice and carefully maintains the level of sedation, allowing the dentist to undertake traumatic dental procedures safely on a relaxed patient.

Other major benefits of the use of propofol include reliable amnesia and an extremely rapid recovery period.

Propofol also has very good antiemetic properties, therefore reducing any likelihood of nausea or vomiting. The only disadvantage of this system for optimum results is that it requires a specialist anaesthetist to perform this technique.

There are two reasons for this requirement:

  1. The delivery of the propofol has to be monitored constantly, ensuring that the patient is kept at a constantly appropriate level of sedation during treatment.
  2. The TCI pump has to be calibrated to different settings for each patient individually.

Propofol is, to date, a widely accepted drug for use in sedation in dentistry. It has been endorsed by the The Royal College of Anaesthetists in England, by the Scottish Dental Clinical Effectiveness Programme, by recent publications in Sedation in Dentistry, and recognised in Post Graduate Training in Dentistry.

About the author

Aldo Ceresa is the clinical lead at Cadden Dental Clinic in Glasgow. He has over 34 years’ of experience in treating patients successfully under sedation having been instrumental in setting up the NHS sedation service at Glasgow Dental Hospital.

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