DAANCE Anesthesia Techniques 2 — Questions and Answers
Question 1: Which technique is used to prevent unintentional intravascular injection of local anesthetic?
- Using a larger gauge needle to feel resistance changes in tissue
- Aspirating before injection to check for blood return (Correct answer)
- Injecting rapidly to minimize patient discomfort
- Using the highest concentration available for maximum effect
Correct answer: Aspirating before injection to check for blood return
Aspiration before injection checks for blood in the syringe, indicating intravascular needle placement. Negative aspiration reduces (but does not eliminate) intravascular injection risk.
Aspiration is a mandatory technique before every local anesthetic injection. A positive aspirate (blood in syringe) indicates intravascular placement; the needle must be repositioned. Aspiration is not 100 percent reliable in small veins or with ultra-fine needles, but remains the standard safety check. Slow injection further reduces toxicity risk.
Question 2: Inhalation sedation with nitrous oxide/oxygen (N2O/O2) is MOST appropriate for which patient?
- A patient with severe obstructive pulmonary disease dependent on hypoxic drive
- A mildly anxious, cooperative adult for a routine restoration (Correct answer)
- A patient with a blocked nasal airway due to chronic sinusitis
- A patient in the first trimester of pregnancy
Correct answer: A mildly anxious, cooperative adult for a routine restoration
A mildly anxious, cooperative adult with no contraindications is the ideal candidate for nitrous oxide/oxygen sedation.
Contraindications to N2O include: severe COPD with CO2 retention (hypoxic drive concern), blocked nasal passages (delivery requires nasal breathing), first trimester pregnancy, active pulmonary infections, and claustrophobia with the nasal mask. N2O is ideal for mild anxiety in ASA I to II patients.
Question 3: The technique of titration in IV sedation means:
- Administering the entire calculated dose as a single bolus for consistency
- Incrementally administering small doses and assessing response before giving more (Correct answer)
- Using the highest safe dose from the start to ensure adequate sedation
- Mixing all planned drugs in a single syringe to simplify administration
Correct answer: Incrementally administering small doses and assessing response before giving more
Titration involves giving small incremental doses, pausing to assess clinical effect, and proceeding only if more sedation is needed - preventing inadvertent oversedation.
The pharmacokinetic variability between patients makes single-dose bolus sedation dangerous. Titration accounts for age, weight, medical status, drug interactions, and individual sensitivity. Standard titration technique: give initial dose, wait one circulation time (60 to 120 sec), assess sedation level, titrate additional small increments until target achieved.
Question 4: Which statement about the IV induction drug propofol is CORRECT?
- It has analgesic properties equivalent to opioids at sedation doses
- It is suitable for use in a syringe shared between multiple patients due to its antimicrobial preservatives
- It requires a separate analgesic agent because it provides no analgesia (Correct answer)
- It causes bronchodilation and is the preferred sedative in severe asthma
Correct answer: It requires a separate analgesic agent because it provides no analgesia
Propofol provides sedation, hypnosis, and amnesia but NO analgesia. An opioid or local anesthetic must be used concurrently for painful procedures.
Propofol mechanism (GABA-A potentiation) produces CNS depression without activating opioid receptors. Procedures involving pain require separate analgesia (opioid, local anesthetic, or NSAID). Propofol strict single-patient preparation requirements exist because its lipid emulsion is a bacterial growth medium - multi-patient use is absolutely contraindicated.
Question 5: The concept of rescue in monitored anesthesia care (MAC) sedation means the provider must be capable of:
- Prescribing post-procedure pain medications
- Rescuing a patient who moves to a deeper level of sedation than intended (Correct answer)
- Providing emotional support for an anxious patient
- Ensuring the patient does not feel any pain during the procedure
Correct answer: Rescuing a patient who moves to a deeper level of sedation than intended
Rescue capability requires that the provider can recognize and manage inadvertent deep sedation or loss of airway, including bag-valve-mask ventilation and reversal drug administration.
The ASA/ADSA principle of rescue states: anyone providing a level of sedation must be capable of rescuing a patient who inadvertently progresses to the next deeper level. For moderate sedation, the provider must manage deep sedation (airway support, reversal agents). This requirement drives airway training and emergency drug availability standards.
Question 6: Topical anesthesia applied before IV catheter insertion in pediatric patients primarily reduces:
- Systemic drug requirements for subsequent sedation by 50 percent
- Pain and anxiety associated with venipuncture, improving the induction experience (Correct answer)
- The risk of phlebitis from IV catheter materials
- The depth of sedation produced by induction agents
Correct answer: Pain and anxiety associated with venipuncture, improving the induction experience
EMLA cream or LMX4 applied 45 to 60 minutes before venipuncture significantly reduces the pain of needle insertion, decreasing procedural anxiety in children.
EMLA (eutectic mixture of lidocaine 2.5 percent plus prilocaine 2.5 percent) and LMX4 (liposomal lidocaine 4 percent) are the most commonly used topical anesthetics for venipuncture preparation. They must be applied under occlusive dressing for 45 to 60 minutes. Reducing IV insertion pain is a major component of pediatric procedure anxiety management.
DAANCE Anesthesia Techniques 2
Which technique is used to prevent unintentional intravascular injection of local anesthetic?