Induction Agents Flashcards
What is the standard IV induction dose of propofol for a healthy adult?
1.5–2.5 mg/kg
Standard dosing for propofol in adults.
What is the usual onset time of action for propofol IV?
10–20 or 15-30 seconds
Rapid onset characteristic of propofol.
How long does a single IV bolus of propofol usually last?
2-8 minutes
Duration of action for propofol.
What is the primary mechanism of action of propofol?
GABA-A receptor potentiation
Propofol enhances GABA-A receptor activity.
Which of the following is a known clinical effect of propofol?
Antiemesis
Propofol has antiemetic properties.
Which clinical scenario is propofol preferred over etomidate?
Sedation for short outpatient procedures with PONV risk
Propofol is often used in outpatient settings.
Which side effect of propofol is most commonly observed during induction?
Hypotension
Hypotension is a notable side effect during induction.
Which formulation property of propofol requires strict aseptic technique during handling?
Lipid emulsion base
The lipid emulsion increases the risk of contamination.
Propofol has both hypnotic and analgesic properties.
False
Propofol is primarily hypnotic, not analgesic.
Propofol can cause dose-dependent respiratory depression.
True
Respiratory depression is a risk with higher doses.
Propofol reduces intracranial pressure and cerebral metabolic rate.
True
Beneficial effects on ICP and CMRO₂.
The antiemetic effect of propofol makes it suitable for patients with high PONV risk.
True
Antiemetic properties are advantageous for PONV.
Propofol is primarily metabolized in the kidneys.
False
It is metabolized in the liver.
Propofol infusion syndrome is more common with prolonged high-dose infusions.
True
PRIS is associated with high-dose and prolonged use.
Propofol causes minimal cardiovascular depression, making it ideal in hypotensive patients.
False
Propofol can cause hypotension.
What is the typical induction dose range of propofol in mg/kg?
1.5–2.5 mg/kg IV
Standard dosing for IV induction.
Name two reasons propofol is often chosen for outpatient or ambulatory surgery.
- Rapid onset
- Recovery, antiemetic properties
Key benefits for outpatient procedures.
What syndrome is associated with prolonged, high-dose propofol infusion?
Propofol Infusion Syndrome (PRIS)
A serious complication of prolonged use.
List three key clinical effects of propofol on the CNS, respiratory system, and cardiovascular system.
- CNS: decreased ICP and CMRO₂
- Respiratory: apnea and depression
- Cardiac: hypotension and bradycardia
Diverse effects across systems.
In what type of patient should you use caution when giving propofol?
Patients who are hemodynamically unstable or hypovolemic due to its hypotensive effects
Caution due to hypotensive properties.
Why does propofol cause pain on injection, and how can this be minimized?
Due to the lipid emulsion; pain can be reduced by lidocaine pretreatment or larger vein use
Common issue with administration.
What is the typical IV induction dose of etomidate in an adult?
0.1–0.4 mg/kg
Standard dosing for etomidate.
What is the approximate onset time of etomidate when given intravenously?
15–30 or 5-15 seconds
Quick onset characteristic of etomidate.
How long does the hypnotic effect of a single etomidate dose typically last?
5–10 or 3-8 minutes
Duration of action for etomidate.
What is the main mechanism of action of etomidate?
Potentiation of GABA-A receptors and depresses RAS
Mechanism involves GABA-A receptor enhancement.
Which of the following best describes etomidate’s cardiovascular profile during induction?
Preserves hemodynamic stability
Minimal cardiovascular effects.
Etomidate is most appropriate in which clinical scenario?
A trauma patient with severe hypotension
Ideal for hemodynamically unstable patients.
Which enzyme is inhibited by etomidate, leading to adrenal suppression?
11-β-hydroxylase
Inhibition leads to decreased cortisol production.
Which of the following is a common side effect of etomidate after administration?
Myoclonus
Myoclonus can occur post-administration.
Etomidate causes minimal respiratory depression compared to propofol.
True
Etomidate is advantageous for respiratory stability.
Etomidate provides both hypnotic and analgesic effects.
False
Etomidate is primarily hypnotic.
Etomidate is useful for patients with head trauma due to its reduction in intracranial pressure.
True
Beneficial effects on ICP.
Repeated doses or continuous infusions of etomidate are commonly used in ICU sedation.
False
Not recommended due to adrenal suppression.
Pain on injection can occur with etomidate use.
True
Injection discomfort is possible.
Etomidate does not affect adrenal function with a single induction dose.
False
Even a single dose can suppress adrenal function.
What is the usual IV induction dose range of etomidate in mg/kg?
0.1–0.4 mg/kg
Standard dosing for IV induction.
Why is etomidate considered the induction agent of choice in critically ill or hemodynamically unstable patients?
It has minimal effects on blood pressure, heart rate, and cardiac output
Stability is key for critical patients.
What is the most concerning endocrine side effect of etomidate, especially with repeated use?
Adrenocortical suppression due to inhibition of 11-β-hydroxylase
Significant concern in repeated dosing.
What physical side effect can occur shortly after etomidate administration and may be mistaken for seizure activity?
Myoclonus
Myoclonus can mimic seizures.
What are the benefits and drawbacks of using etomidate in neuroanesthesia?
- Benefit: reduces ICP and cerebral metabolic rate
- Drawback: does not provide analgesia and causes adrenal suppression
Important considerations for neuroanesthesia.
How long does it take for etomidate to wear off after a single IV bolus dose?
Approximately 5–10 minutes
Quick recovery time.
What is the typical IV induction dose of ketamine in adults?
1–2.5 mg/kg
Standard dosing for ketamine.
What is the onset time of action of ketamine given IV?
10–30 or 15-30 seconds
Rapid onset characteristic of ketamine.
What is the approximate duration of a single IV bolus of ketamine?
10–20 or 5-15 minutes
Duration of action for ketamine.
Which receptor is primarily antagonized by ketamine?
NMDA receptor
Ketamine’s primary mechanism of action.
Which of the following is NOT a typical clinical effect of ketamine?
Bronchoconstriction
Ketamine typically causes bronchodilation.
Which patient population might benefit most from ketamine for induction?
Hypovolemic trauma patients
Ketamine is useful in trauma scenarios.
What is a common psychological side effect of ketamine during emergence?
Hallucinations and delirium
Psychological effects during recovery.
Which property makes ketamine useful in asthmatic patients?
Potent bronchodilation
Beneficial for patients with bronchospasm.
Ketamine causes significant respiratory depression similar to propofol.
False
Ketamine typically preserves respiratory function.
Ketamine increases heart rate and blood pressure.
True
Ketamine can stimulate cardiovascular parameters.
Ketamine can be administered via IV, IM, oral, intranasal, and rectal routes.
True
Versatile administration routes for ketamine.
Ketamine is contraindicated in patients with increased intracranial pressure.
Historically True, but now considered controversial and patient-specific
Clinical guidelines have evolved.
Ketamine is a useful drug for procedural sedation in pediatric patients.
True
Commonly used in pediatric sedation.
Ketamine causes dissociative anesthesia by blocking GABA receptors.
False
It blocks NMDA receptors, not GABA.
Ketamine maintains pharyngeal and laryngeal reflexes.
True
Preserves airway reflexes during sedation.
What is the typical IV induction dose range of ketamine in mg/kg?
1–2.5 mg/kg IV
Standard dosing for IV induction.
Name two clinical effects that make ketamine unique among anesthetic agents.
- Provides analgesia
- Preserves airway reflexes
Unique properties of ketamine.
Why is ketamine often chosen for asthmatic or bronchospastic patients?
It has bronchodilatory effects
Useful for patients with airway constriction.
What are common emergence phenomena associated with ketamine?
- Hallucinations
- Delirium
- Vivid dreams
Psychological effects on emergence.
How can the emergence reactions from ketamine be minimized?
By co-administering benzodiazepines like midazolam
Co-administration helps reduce side effects.
What is ketamine’s effect on cardiovascular parameters?
It increases heart rate, blood pressure, and cardiac output
Ketamine’s stimulatory effects on the heart.
In what clinical situations would ketamine be a poor choice for induction?
Patients with uncontrolled hypertension, ischemic heart disease, or active psychosis… or ICP
Contraindications for ketamine use.
Ketamine Fun Facts
- Dissociates from Thalamus = nystagmus gaze and prosialogogue
- Useful in various clinical scenarios
Interesting characteristics of ketamine.
Ketamine When to Use
- Chronic Pain/Opioid Use
- Burn Patients
- Uncooperative Patients IM
- Asthmatics and Bronchospasm
- Hypovolemia/Trauma
Indications for ketamine administration.
