3 Feb Induction Meds1 (Barbituates and Propofol) Flashcards
What is the mechanism of action of propofol?
Propofol acts as a GABA receptor agonist.
What are the cardiovascular effects of propofol?
Decreases systolic blood pressure, causes bradycardia, and inhibits vascular smooth muscle contraction.
True or False: Propofol suppresses somatosensory evoked potentials.
False.
What is propofol infusion syndrome characterized by?
Lactic acidosis, bradyarrhythmias, and rhabdomyolysis.
Fill in the blank: Propofol decreases cerebral blood flow and _______.
cerebral metabolic rate of oxygen.
What EEG changes are associated with propofol?
Delta waves during induction and recovery.
What are the effects of propofol on ventilation?
Dose-dependent depression of ventilation, leading to apnea.
What should be monitored when using propofol?
Heart rate, ventilation, and signs of propofol infusion syndrome.
What is the significance of understanding pharmacokinetics in anesthesia?
It is crucial for precise dosing and understanding drug effects on different patient populations.
What is the clinical application of propofol in procedural sedation?
Used for inducing sedation and analgesia during procedures.
What type of patients require careful monitoring when using propofol?
Elderly and pediatric patients.
What is the importance of the drug index in the pharmacology course?
It expands knowledge on drug effects, indications, and interactions.
List the types of EEG waves discussed.
- Delta (deep sleep) * Theta (light sleep) * Alpha (awake but relaxed) * Beta (concentrating) * Gamma (testing)
What is a potential risk of high-dose propofol infusions?
Propofol infusion syndrome.
Fill in the blank: Propofol can cause _______ on injection.
pain.
What are the implications of propofol on liver and renal function?
It does not affect liver transaminase enzymes or creatinine concentrations but can cause hepatocellular injuries with prolonged infusions.
What is the role of atropine when using propofol?
To mitigate bradycardia.
What is the significance of understanding the stages of general anesthesia?
To ensure patient safety during the induction and emergence phases.
True or False: Propofol has minimal impact on the hypoxic pulmonary vasoconstriction response.
True.
What is the recommended approach for managing pain on injection with propofol?
Use lidocaine and larger veins for IV access.
What are the potential effects of propofol on intraocular pressure?
Decreases intraocular pressure, beneficial for certain patient positions.
What is the importance of monitoring for signs of propofol infusion syndrome?
Early detection can prevent severe complications like cardiogenic shock.
What is the recommended follow-up for patients receiving high-dose propofol?
Monitor for lactic acidosis and bradyarrhythmias.
What is the purpose of using small doses or titrating little doses of hypnotic drugs?
To calm patients without getting them overly agitated
This is particularly relevant in pre-operative settings.
What is procedural sedation also known as?
Monitored Anesthesia Care (MAC)
This term is synonymous with conscious sedation.
What is the primary goal of procedural sedation?
To induce a depressed level of consciousness, allowing patients to tolerate unpleasant procedures
This is achieved through a combination of sedatives and analgesics.
What are the two types of effects that sedatives and analgesics can have when combined?
Cumulative and synergistic effects
Cumulative effects occur when drugs add together, while synergistic effects occur when their combination produces a greater effect than the sum of their individual effects.
What is general anesthesia?
A state of drug-induced unconsciousness
It is achieved through intravenous anesthetics targeting the brain.
What are the four stages of general anesthesia?
- Stage 1: Analgesia
- Stage 2: Delirium
- Stage 3: Surgical anesthesia
- Stage 4: Medullary paralysis
These stages describe the progression of anesthesia from light sedation to deep unconsciousness.
What are the protective airway reflexes that should be maintained during stage one of anesthesia?
- Sneezing
- Coughing
- Swallowing
- Gagging
These reflexes are important for maintaining airway safety.
What happens during stage two of general anesthesia?
Characterized by excitement and cardiovascular instability
This stage is the most dangerous and is typically passed through quickly.
What is the primary effect of propofol during induction?
It induces sympatholysis and amnesia
Propofol can also provide some analgesic effects at higher doses.
What is the consequence of not extubating patients in stage two?
Increased risk of aspiration pneumonitis
This can lead to significant complications post-operatively.
What is the significance of pharmacokinetics in anesthesia?
It describes how anesthetics are distributed through the cardiovascular system
Understanding this helps in predicting the effects of anesthetic agents on the body.
True or False: The hearing is the last sensory experience that patients lose during anesthesia.
True
This is important for clinicians to consider when communicating with patients pre-operatively.
Fill in the blank: The administration of a combination of sedatives and analgesics during anesthesia is known as _______.
procedural sedation
This technique is designed to maintain patient comfort during procedures.
What is the role of NMDA receptors in anesthesia?
They are involved in pain modulation
Certain anesthetics, like ketamine, act on these receptors.
What is the importance of the vessel rich group in anesthesia?
It receives the majority of cardiac output, crucial for anesthetic delivery
This group includes organs like the brain that are highly sensitive to anesthetic agents.
What are the potential complications associated with stage two of anesthesia?
Laryngospasm and active emesis
Monitoring is critical during this stage to manage these complications.
What happens in stage two of general anesthesia?
Patients may experience laryngospasm or active emesis due to medications.
Stage two is characterized by excitement and increased sympathetic activity.
What is the significance of stage three in general anesthesia?
Absence of response to surgical pain or laryngoscopy allows for intubation.
This stage includes hypnosis, analgesia, muscle relaxation, and amnesia. AKA the surgical plane
What are the consequences of entering stage four of anesthesia?
Cessation of spontaneous respiration, medullary cardiac reflexes, hypotension, and possibly bradycardia.
This stage can lead to death due to severe complications and not considered safe anesthesia even with an established airway.
What is the process of emergence from anesthesia?
Reverse medications, monitor airway protection, and assess tidal volume before extubation.
Emergence involves returning to stage one from stage three.
How quickly can a patient enter stage four of anesthesia?
Typically within 5 to 15 seconds.
This rapid transition highlights the importance of monitoring.
What is the effect of IV induction on the timing of anesthesia stages?
IV induction is quicker, taking seconds compared to inhalation induction, which can take minutes.
IV induction leads to faster progression through anesthesia stages.
What is a common property of barbiturates?
They are derived from barbituric acid and were once used as a gold standard for induction agents.
Barbiturates are no longer widely used due to safety concerns.
What is the mechanism of action for barbiturates?
They act as GABA agonists, promoting hypnosis and increasing cerebral blood flow. They also increase the cerebral metabolic rate of oxygen.
* coupled
What happens to cerebral blood flow and metabolic rate when using induction agents?
Cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) are coupled; both increase or decrease together (typically in IV anesthetics and uncoupled in inhaled anesthetics)
This relationship is important in avoiding complications during anesthesia.
True or False: Barbiturates provide analgesia.
False. Barbiturates do not provide analgesic effects.
Supplementation with opioids is necessary when using barbiturates.
What is the typical onset time for barbiturates?
Rapid onset within 30 seconds.
This rapid effect is due to fast redistribution to the brain.
What is the significance of redistribution in the context of barbiturates?
Redistribution from the brain to other tissues leads to rapid awakening and affects dosing.
Redistribution acts as a reservoir, impacting re-sedation and recovery time.
Fill in the blank: The most common barbiturate used for induction is ______.
Thiopental.
What are the pharmacokinetics of barbiturates in relation to prolonged infusions?
They can lead to lengthy context-sensitive half-times due to being stored in fat tissues.
This storage can cause delayed recovery.
What is a potential complication of using barbiturates in elderly patients?
Increased fat stores can act as a reservoir, affecting drug metabolism and recovery.
Elderly patients may require different dosing due to altered pharmacokinetics.
What occurs to perfusion in a patient in shock?
There would be decreased perfusion due to sluggishness, probably of the cardiac output.
In elderly patients, what is a significant consideration regarding fat and drug distribution?
Fat becomes a reservoir for fat-soluble induction agents, acting as its own IV bag.
What should dosing for induction agents be based on in elderly patients?
Dosing should be based on ideal body weight or lean body weight.
What metabolic process occurs in the liver for drug elimination?
Metabolism occurs through the liver via hepatocytes, with 99% excretion through the renal system.
How does protein binding affect the action of drugs like thiopental?
High protein binding (70-85% and predominantly albumin) allows drugs to detach from blood proteins and produce unconsciousness again.
What is the effect of high protein binding capacity on drug metabolism?
It generally results in a longer duration of action.
What is one of the uses of thiopental due to its lipid solubility?
It is used for pre-medication.
What is a common adverse effect associated with thiopental?
It can cause a hangover effect lasting a day or two.
What is the significance of thiopental’s ionized and non-ionized components?
The non-ionized component is more lipid soluble and favors acidosis, while the ionized component lingers more intravascularly.
What is the typical dose of thiopental?
The dose is usually 4 to 5 mg per kg IV.
What is the blood-fat partition coefficient for thiopental?
The blood-fat partition coefficient is 11.
What does the partition coefficient describe?
It describes the distribution of a given agent at equilibrium.
What are the dosages of methohexital?
- IV The dose is 1.5 mg per kg.
- PR 20-30 mg/kg
- IV gtt consideraation: postop seizure activity in 1 of 3 patients
What is a notable side effect of methohexital?
It lowers the seizure threshold, making patients more prone to seizures (1 out of 3 patients).
What is the common route of administration for thiopental in uncooperative pediatric patients?
Rectal administration 20-30 mg/kg.
What is the mechanism of action for propofol?
It is a gamma amino butyric acid agonist.
What is the typical dose range for propofol?
The dose range is 1.5 to 2.5 mg per kg IV.
What are the cardiovascular effects of thiopental?
It can produce a decrease in systolic blood pressure and an increase in heart rate.
What should be done if thiopental is inadvertently administered into an artery?
Immediate action is needed to prevent intense vasoconstriction and pain. Vasodilators like lidocaine need to be administered immediately to prevent necrosis.
What is the effect of volatile agents compared to IV drugs on sensory output?
Volatile agents tend to suppress sensory output.
What is an important consideration for patients on anticoagulants when using enzyme inducers?
Patients may be prone to thromboembolic events if anticoagulation is not managed properly.
What is the relationship between adipose tissue and blood volume?
Adipose tissue has decreased vascular supply, leading to less blood volume.
What type of drug is propofol?
A gamma amino butyric acid agonist
Propofol is a common anesthetic agent known for its rapid onset and recovery.
What is the typical dosage range for propofol?
1.5 to 2.5 mg per kg, IV
Dosage may vary based on the specific clinical scenario.
What is the dosage for consciousness or procedural sedation with propofol?
25 to 100 mcg per kg per minute for induction; 100 to 300 mcg per kg per minute for maintenance
These dosages are specific for monitored anesthesia care.
How quickly does propofol produce unconsciousness?
Within 30 seconds
Rapid injection (less than 15 seconds) is key for quick onset.
What are the advantages of using propofol in outpatient procedures?
Quick onset, quick offset, rapid return to consciousness, minimal CNS effects
These properties make it suitable for procedures like dental anesthesia.
What is the composition of 1% propofol?
10% soybean oil, 1.2% purified egg phosphatide, glycerol
These components aid in emulsification and stability of the solution.
What type of allergy should be considered before administering propofol?
Egg allergies
Propofol contains egg phosphatide, which can cause allergic reactions.
True or False: Propofol can support bacterial growth once punctured.
True
It is important to use propofol within six hours after puncturing to prevent contamination.
What is the elimination half-time of propofol?
0.5 to 1.5 hours
This short half-time allows for rapid recovery from anesthesia.
What is the context-sensitive half-time for propofol based on an eight-hour infusion?
40 minutes
This reflects the drug’s pharmacokinetics during prolonged use.
Fill in the blank: The mechanism of action of propofol involves increasing transmembrane _______ conductance.
chloride
This action leads to hyperpolarization of post-synaptic cell membranes.
What is the primary organ for the clearance of propofol?
Lungs
The lungs have a greater capacity for drug uptake than the liver.
What happens to propofol metabolism in patients with cirrhosis?
Similar awakening time compared to normal patients
This indicates that hepatic impairment does not significantly affect propofol’s effects.
What is a disadvantage of propofol due to its lipid content?
Increased plasma triglyceride levels
This can be a concern with prolonged intravenous infusions.
What is the effect of propofol on cardiovascular parameters?
Decreases systemic blood pressure
Propofol has bradycardic effects, which can influence heart rate.
What is the role of cytochrome P450 in propofol metabolism?
Converts propofol into water-soluble metabolites
These metabolites can be eliminated through urine.
What is the primary concern when administering propofol to OB patients?
Ion trapping in neonatal circulation
Careful dosing is necessary to avoid effects on the fetus.
True or False: Propofol is contraindicated in pediatric patients.
Trick question. FDA reccomends against it but as anesthesia providers, we administer to pedi all of the time.
Consider it’s warnings in pedi population seriously but don’t withhold it if it is the best medication for the job!
Propofol has a black box warning but can be used with clinical consideration.
What is a common practice before administering propofol to reduce pain on injection?
Administering lidocaine
This can alleviate discomfort caused by the propofol injection.
What is the black box warning associated with propofol?
Profound bradycardia and asystole with healthy adult patients.
*Also increased risk in pediatric population
Other medications with black box warnings include succinylcholine.
How is propofol used in anesthesia?
It can be used for induction, continuous IV infusion, or in combination with other anesthetic drugs
Propofol is commonly used in both outpatient and inpatient settings.
What is the recommended induction dose of propofol for adults?
10 to 15 mg IV
Doses may vary based on patient factors.
What is the typical dose range for conscious sedation using propofol?
25 to 100 ug/kg per minute
Supplementation with analgesics like fentanyl may be necessary.
What are the metabolic effects of propofol on children?
Children require higher doses due to higher metabolism, larger volume of distribution, and higher clearance rates
This is influenced by their higher heart rates.
What is the recommended adjustment for propofol dosage in elderly patients?
Lower the induction dose by approximately 25 to 50%
This is due to decreased muscle mass and altered drug distribution.
What are the effects of propofol on post-operative nausea and vomiting?
Propofol is more effective than Zofran for preventing post-operative nausea and vomiting
It has a direct depressant effect on the vomiting center in the hindbrain.
What is propofol’s role in patients with asthma?
It acts as a bronchodilator
This makes it suitable for outpatient procedures in asthmatic patients.
What is the potential risk associated with high doses of propofol?
It may decrease cerebral perfusion pressure
This necessitates monitoring and support of mean arterial pressure.
True or False: Propofol is a trigger for malignant hyperthermia.
False
Volatile agents and succinylcholine are known triggers.
What are the EEG wave patterns associated with propofol?
Propofol induces theta and delta waves depending on dose
Delta waves are associated with deep sleep, while theta waves are associated with light sleep.
What is propofol infusion syndrome?
A condition associated with prolonged infusions of propofol, potentially leading to metabolic disturbances
Symptoms may include green urine due to phenol metabolites (does not impair kidneys).
What is the effect of propofol on heart rate?
It can cause bradycardia due to its effects on the sympathetic nervous system
Monitoring is crucial, especially in pediatric patients.
Fill in the blank: Propofol has _______ effects on pain.
minimal to none
Supplementation with opioids is often required for effective pain management.
What is the impact of propofol on liver function?
Normal liver function tests are expected, but prolonged use can lead to hepatocellular injury
Monitoring liver enzymes may be necessary in certain patient populations.
What is the typical dosing strategy for propofol in mechanically ventilated patients?
It is used for sedation due to its rapid onset and offset
This helps in managing ventilatory support effectively.
What are the common side effects of propofol?
Hypotension, bradycardia, and respiratory depression
These effects warrant careful patient monitoring during anesthesia.
What is propofol infusion syndrome?
A condition that can occur with high-dose infusions of propofol, characterized by lactic acidosis, refractory bradycardia, and potentially fatal outcomes.
It can affect both children and adults, especially with doses over 75 mcg/kg/min for longer than 24 hours.
What can cause green urine when using propofol?
Interaction with phenols released by propofol, not affecting renal function.
This is a benign phenomenon observed in patients receiving propofol.
What does cloudy urine indicate in patients receiving propofol?
It may indicate dehydration or uric acid crystallization, but does not alter renal function.
Increasing crystalloids may be necessary for these patients.
How can pain on injection of propofol be mitigated?
By using lidocaine, especially in peripheral veins.
Pain is generally less in larger veins, such as the antecubital vein.
What effect does propofol have on intraocular pressure?
It can decrease intraocular pressure, beneficial for patients in a Trendelenburg position.
This is particularly important for patients with glaucoma.
True or False: Propofol inhibits platelet aggregation.
True
This can lead to clotting issues in some patients, though not significantly.
What are potential side effects of propofol mentioned?
Prolonged myoclonus, involuntary muscular movements, and allergic reactions.
These effects may cause confusion regarding the patient’s consciousness level.
What is the abuse/misuse rate of anesthetic drugs among anesthesia providers?
It has increased from 5% to 15% over the years.
High job stress and access to anesthetic drugs contribute to this issue.
What is the responsibility of registered nurses regarding drug abuse?
To report and intervene if there is suspicion of drug abuse among colleagues.
Early intervention can prevent potential overdoses.
What diagnostic methods are used for propofol infusion syndrome?
Arterial blood gas analysis and serum lactate concentrations.
These tests help determine the presence of lactic acidosis.
What can happen in the late stages of propofol infusion syndrome?
Propofol infusion syndrome (PRIS) leads to cardiogenic shock by impairing mitochondrial function within cardiac muscle cells, causing a significant decrease in energy production which ultimately results in weakened cardiac contractility and reduced cardiac output, leading to systemic circulatory collapse; this is further exacerbated by propofol’s direct negative inotropic effects on the heart, essentially making the heart unable to effectively pump blood throughout the body.
Early diagnosis and intervention are crucial to prevent severe outcomes.
Fill in the blank: Propofol infusion syndrome can result in _______ and _______.
lactic acidosis, bradyarrhythmias
Rhabdomyolysis is also a possible complication.
