Chapter 1
Conscious IV Sedation Utilizing Midazolam

Jess Liu

INTRODUCTION

Dental fear and anxiety are the common reasons why patients avoid seeking proper dental care. A survey conducted in the US has reported up to 30.5% of both US adults and adolescents experience a moderate to high dental fear (Gatchel 1989). Therefore, it is important for dentists to understand the management of dental fear and anxiety as an integral component of the overall treatment.

As defined by the American Society of Anesthesiologists (see Table 1.1), the continuums of depth of sedation are:

• Minimal Sedation: Normal response to verbal stimulation.
• Moderate Sedation: Purposeful response to verbal or tactile stimulation.
• Deep Sedation: Purposeful response following repeated or painful stimulation.
• General Anesthesia: Unarousable even with painful stimulus.

According to the American Society of Anesthesiologists moderate sedation is also known as "Conscious Sedation," and by definition, conscious sedation is "a drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained."

Conscious sedation can be achieved by different routes of administration such as enteral or parenteral administration. For the purpose of this chapter, parenteral administration of conscious sedation limited to intravenous administration of Midazolam (Versed) will be reviewed.

Training in Intravenous Conscious Sedation

While IV conscious sedation is relatively safe to practice, only a qualified and well-trained healthcare provider who is able to manage emergency complications should perform the practice. Dentists who practice IV conscious sedation are mandated by all states to be certified by an approved continuing education program. Furthermore, each state is governed by its own rules and regulations for the administration of conscious sedation, therefore it is important to verify with the individual state dental board for the proper requirements to obtain a permit to practice IV conscious sedation.

MIDAZOLAM (VERSED)

Midazolam is a water soluble, short acting benzodiazepine central nervous system (CNS) depressant. Pharmacologically, it produces anxiolytic, hypnotic, anterograde amnestic, muscle relaxation, and anticonvulsant effects (Reves et al. 1985). Metabolized in the liver by cytochrome P450 enzymes, its mechanism of action is through binding of the GABAA receptors, (causing an influx of chloride ion which causes hyperpolarization of the neuron's membrane potential) creating a neural inhibition effect.

The onset of intravenous administration of midazolam is relatively fast with a short acting duration. Intravenous administration of 5 mg of midazolam in healthy adults has shown to take effect one to two minutes after administration and has a half-life of approximately one to three hours (Smith et al. 1981).

It is important to understand that the use of midazolam is to produce conscious sedative effects and does not replace the need for proper local anesthesia. Therefore proper anesthetic should be administered prior to the starting of the dental procedure.

Table 1.1 Continuum of sedation: definition and levels (2004).

a Reflex withdrawal from a painful stimulus is NOT considered a purposeful response.

ARMAMENTARIUM

• Monitoring equipment for:
  • Non-invasive Blood Pressure (NIBP)
  • Electrocardiogram (EKG)
  • Pulse Oximetry
  • Capnography
• IV Supplies:
  • 0.9% Sodium Chloride Injection 250 ml bag
  • Primary IV set (100")
  • 22 Gauge × 1" Introcan Safety® IV Catheter
  • 24 Gauge × ¾" Introcan Safety IV Catheter
• Basic Supplies:
  • 1 ml Insulin Syringe
  • Blunt Plastic Cannula
  • Nasal Cannula
  • Supplemental Oxygen
  • 1" Latex free Tourniquet
  • 3M Tegaderm Film Transparent Film Dressing
  • 3M Transpore Tape
  • Gauze
  • Band-Aids
  • Alcohol Wipes
• Basic Medications:
  • Midazolam 5 mg/1 cc
  • Flumazenil 5 cc
  • ACLS Emergency Medical Kit (HealthFirst)

Please see Figure 1.1.

STEPS IN IV SEDATION

Patient pre-op evaluation: As with all dental procedures, a thorough review of the patient's medical history is essential to ensure safe and successful treatment. Review of the patient's medical history with complete review of the system, current medications, as well as drug allergies will provide you the necessary information to assess the patient utilizing the ASA Physical Status Classification System (see Table 1.2). The authors recommend limiting the administration of conscious sedation with patients with ASA Physical status of 2 or less to reduce the chance of medical emergencies.

• Contraindication:
  • Hypersensitivity
  • Acute narrow-angle glaucoma
  • Hypotension
  • Pregnancy
  • Renal disease
  • Critically ill patients
• Pre-op instructions
  • No food or drinks eight hours prior to procedure.
  • Please wear comfortable loose-fitting clothing with short sleeves to allow for monitoring of your blood pressure.
  • Must be accompanied by a person of legal age to escort you home.
  • No sedatives for 24 hours before appointment.
• Day of Procedure:
  • Seat the patient
  • Review medical history. If patient has medical history of asthma instruct patient to take two puffs of asthma inhaler prior to starting of procedure.

    Figure 1.1 Armamentarium needed to provide sedation: monitor, drug, IV sedation set.

    Table 1.2 ASA physical status classification (American Society of Anesthesiologists 2015).

    ASA physical status classification system ASA Physical Status 1 A normal healthy patient ASA Physical Status 2 A patient with mild systemic disease ASA Physical Status 3 A patient with severe systemic disease ASA Physical Status 4 A patient with severe systemic disease that is a constant threat to life ASA Physical Status 5 A moribund patient who is not expected to survive without the operation ASA Physical Status 6 A declared brain-dead patient whose organs are being removed for donor purposes

    Figure 1.2 Pulse oximetry, oxygen cannula, blood pressure cuff.

  • Attach patient monitors (See Figure 1.2) for:
    • Blood pressure
    • Electrocardiography (EKG)
    • Pulse oximetry (Oxygen saturation)
    • Capnography (CO2 partial pressure) Give earliest warning of respiratory distress
  • Record pre-operatory vital signs: Blood pressure, pulse, respiratory rate, oxygen saturation, end tidal CO2 level. If vital signs not within normal range re-evaluate patient for the procedure.

Pre-operative vital signs chart