Ch. 21 Sedative Induction Agents Flashcards
What side effect is important to remember for all sedative/induction agents?
All cause some degree of myocardial depression and can lead to decreased BP
In hemodynamically unstable patients, how should analgesia be managed?
Remember that complete pain control may decrease catecholamine surge and lead to decreased BP and decreased organ perfusion
What are the preferred sedative/induction agents in order?
Etomidate
Ketamine
Propofol
Midazolam (very distant last resort option)
How does morbid obesity complicate dosing for sedative/induction agents and what should be done?
Increased fat => increased volume of distribution => increased dose required to work
However, sudden push of a large dose will have a larger myocardial depression effect leading to decreased BP
Use lean body weight for obesity
LBW=IBW + 0.3(TBW–IBW)
Except for propofol where IBW is better
Why is dosing different for elderly and what dosing should be used?
Elderly have decreased body water and increased fat as well as increased sensitivity to hemodynamic changes
Should use 1/2 or 2/3 of usual dose
What is the first choice of sedative/induction agent?
Etomidate
What is the dosing, onset, and duration for etomidate?
0.3mg/kg
Onset ~30sec
Lasts 5–10 minutes
What effects/properties does etomidate have? (sedation, analgesia, amnesia, etc.)
Primarily just hypnotic
No analgesia
What effects does etomidate have on hemodynamics?
Relatively none
Very stable hemodynamically
How does etomidate affect ICP and CPP?
Lowers ICP by decreased cerebral blood flow and is neuroprotective through decreased cerebral metabolic rate
Etomidate is an excellent choice for ICP patients
Maintains CPP through stable hemodynamics
Can etomidate be used for reactive airway patients?
Yes, as it doesn’t release histamine, but ketamine or propofol may be better as they have direct bronchodilatory properties
Can etomidate be used in pregnancy or with kids?
Pregnancy category C
Not FDA approved in kids, but may be ok
What is a side effect of etomidate that is not significant?
Myoclonic movements can occur and are common, but are taken care of with NMBA
What is the big side effect of etomidate to always remember?
Adrenal suppression
Lasts up to 72 hours
Decreases cortisol and aldosterone
May be significant particularly in sepsis
When should dose adjustments be made for etomidate?
Decrease dose to 0.2mg.kg in hemodynamically unstable patients
Use LBW in obese pts
What is the usual dose for ketamine for induction?
Onset time?
Duration?
1.5mg/kg
Onset 45–60 seconds (less than a minute)
Lasts 10–20 minutes
What effects/properties does ketamine have?
Analgesia, amnesia, anesthesia
What is a benefit to ketamine in terms of respiratory effects?
Preserves respiratory drive
Has bronchodilatory effects
How does ketamine affect hemodynamics?
Leads to catecholamine release => increased HR and BP as well as bronchodilation
What is the agent of choice for induction in asthma?
Ketamine
What conditions are good to use ketamine for induction?
Reactive airway disease
Hypovolemia or hypotensive
Sepsis
When can ketamine be a poor choice for induction?
Ischemic heart disease as catecholamine release can lead to increased myocardial O2 demand and worsening ischemia
What makes ketamine good for awake laryngoscopy?
Preserves airway reflexes
How does Ketamine affect ICP?
Increases ICP from catecholamine surge, but also increases MAP => increased CPP
Growing evidence towards ketamine being safe in ICP pts
Ketamine is contraindicated in what patients?
Pregnant women
When can ketamine lead to myocardial depression?
In pts who are catecholamine depleted
What are two negative side effects of Ketamine on the airway that can make intubation difficult?
Increased secretions (can pre-treat with atropine or glycopyrrolate) Laryngospasm
Who is more likely to have an emergence reaction with ketamine? How is it treated?
Adults are more likely than kids
Treat with Benzos
What is the dose for propofol?
Onset?
Duration?
1.5mg/kg
Onset ~30sec
lasts 5–10 minutes
What is the effect of propofol on ICP?
Decreases ICP and decreases cerebral metabolism
But also decreases CPP
How does propofol affect hemodynamics?
decreased BP from vasodilation and myocardial depression
Who requires particular caution when using propofol for induction?
Anyone sensitive to hemodynamic changes: Elderly, debilitated, ASA class III/IV, or already with hemodynamic instability
What patients are best for use of propofol induciton?
Stable patients
It is the drug of choice in pregnancy
Also good for reactive airway disease behind ketamine
How and when should propofol dosing be modified?
Decrease by 1/2 or 1/3 if hemodynamic instability or elderly
What are benzos the best drugs for?
Amnesia and sedation
Why are benzos not a good option for induction?
Slow onset
What dosing of versed is used for induction?
0.2–0.3mg/kg
Onset 60–90 sec
Lasts 15–30 minutes
Benzos are contraindicated in which patients?
Pregnancy
Benzos are not great for induction, but are great for what?
Procedural sedation
What are the major downsides to each induction agent?
Etomidate: adrenal suppression
Ketamine: catecholamine surge, bronchial secretions, laryngospasm, emergence
Propofol: hypotension
Versed: slow onset
Which induction agent is best for sepsis?
Ketamine first, then etomidate
Which induction agent is best for pregnancy?
Propofol
Which induction agents are contraindicated in pregnancy?
Ketamine and Versed
Which induction agents are best for reactive airway disease?
Ketamine and propofol
Which induction agent has the least effects on hemodynamics?
Etomidate
Which induction agent is best for hemodynamic compromise?
Ketamine
Which agent is best for ICP?
Etomidate
How is laryngospasm managed?
1) Jaw thrust at laryngospasm notch and BVM with PEEP valve and 100% O2
2) Deepen sedation with propofol 0.5mg/kg if you have time
3) Succinylcholine and intubation
