Characteristics of Common Induction Drugs (Exam 2) Flashcards
Propofol: E 1/2 Time (Hours)
0.5-1.5 Hours
Propofol: Vd (L/kg)
3.5 - 4.5
Propofol: Clearance (mL/kg/min)
30 - 60
Propofol: Effects on BP & HR (increase/Decrease)
BP: Decreased
HR: Decreased
Etomidate: E 1/2 Time
2 - 5 Hours
Etomidate: Vd (L/kg)
2.2 - 4.5
Etomidate: Clearance (mL/kg/min)
10 - 20
Etomidate: Effects on BP & HR (increase/Decrease)
BP: No change - Decreased
HR: No Change
Ketamine: E 1/2 Time
2 - 3 Hours
Ketamine: Vd (L/kg)
2.5 - 3.5
Ketamine: Clearance (mL/kg/min)
16 - 18
Ketamine: Effects on BP & HR (increase/Decrease)
BP: Increased
HR: Increased
Where do all these drugs work?
They all work on GABA!!
Ketamine works at a lot of places
-NMDA as Non-comp. antagonist
-Opioid receptors (mu/kappa/delta)
-GABA A (weak)
Ketamine side effects
-Drooling
-Delirium
-Dissociation
Ketamine: How to treat Drooling and Delirium?
-Glycopyrorolate (0.2mg)
-Versed (admin 5 min. prior to ketamine dose)
Ketamine: Induction Dose
INDUCTION:
-0.5 -1.5 mg/ kg IV
-4-8 mg/kg IM
Ketamine: Maintenance & Sub anesthetic dose
0.2-0.5 mg/kg IV
Ketamine: Post-Op Sedation & Analgesic Dose
1-2 mg/kg/hr
Ketamine: Neuroaxial Analgesia
-Epidural: 30 mg
-Intrathecal/spinal/ subarachnoid: 5-50 mg
Ketamine: Onset & Duration
Onset:
-IV: 1 min
-IM: 5 min
Duration : 10-20 min
Ketamine: Metabolism
-Hepatic, CYP 450
-ACTIVE METABOLITE: Norketamine (1/3 potency of parent, causes prolonged analgesia)
Ketamine: Drug interactions and Effects
-Volatile anesthetic: Hypotension
-NDNMB drugs: Enhanced
-Succinylcholine: Prolonged
Ketamine: CV Effects
-THINK SNS EFFECTS!
- Can cause sudden ↓BP d/t depletion of catecholamine stores.
-Direct myocardial suppressant - Ephedrine won’t work bcuz indirect action
- so give a direct acting vasopressure like phenelyphrine
Ketamine: Pulmonary Effects (There’s a bit here)
-↑ Pulm artery pressure up to 44 mmHG
- No depression of ventilation
- PaCO2 ventilation response maintained
‣ Upper airway relflexes and tone maitained = ↑ of laryngospasms
‣ ↑ Salivation and tracheobrochial mucous secretions
‣ ↑ Bronchodilation (no histamine release)
Ketamine: Other Side Effects
-Benefits: AMNESTIC and ANALGESIC
-BUUUUT…
-Dissociative anesthesia ‣** Nystagmus** ‣ Non- communitave wakefullness ‣ Hypertonic skeletal movements
Ketamine: Contraindication
- Systemic /pulm HTN
- Increased ICP
Etomidate: Metabolism
- Hydrolysis hepatic microsomal enzymes
- Plamsa esterases
Etomidate: Excretion / Clearance
- 85% in urine
‣ 10-13% in bile
-Clearance 5x faster than thiopenthal
***wake up fast
Etomidate: CNS Effects
- ↑ incidence of myoclonus (50-80%) Greater than all others
- Give Benzo or Opiod to inhibit
myclonus (FENT 1-2 mcg/kg
IV)
‣ USE CAUTION WITH SEIZURE
PT!!!
Etomidate: CV Effects
CARDIOPROTECTIVE AGENT
‣ Good for patients with low EF
‣Minimal changes in HR, SV, CO, Contractility
‣ SUDDEN HYPOTENSION w/ HYPOVOLEMIA w/ high 0.45 mg/kg IV induction dose
Etomidate: Resp.
-Ventilation depression < barbs
-Stimulates CO2 medullary centers
Etomidate: Special Considerations
-No analgesia, so you will need multimodal anesthesia
-Adrenocorotical Suppression: Dose depenedent, inhibits the conversion of cholesterol to cortisol
‣↓ STRESS RESPONSE
‣↓ BP
‣↑Mechanical ventilation
time
‣ USE CAUTION w/ Sepsis
and hemorrhage
Etomidate: Adverse Effects
-Adrenocorotical Suppression: -Dose depenedent,
-Inhibits the conversion of cholesterol to cortisol,
‣↓ STRESS RESPONSE
‣↓ BP
‣↑Mechanical ventilation
time
‣ USE CAUTION w/ Sepsis
and hemorrhage
Propofol: Metabolism
-Hepatic: CYP 450
-Metabolites: Water soluble sulfate and glucoronic acid excreted by kidney
Propofol: Context Sensitive Half Time
40 minutes (on 8hr infusions)
Shorter than all barbs, not as lipid soluble
Propofol: Clearance (not just a number!!)
30-60 mL/kg/min
-Plasma (lungs) > Hepatic flow
-Tissue uptake > CYP 450
Propofol: CV
-↓ BP (more than thiopental)
- ↓BP exaggerated in hypovolemia, elderly, LV compromise
Propofol: Resp.
**-Dose Dependent apnea
-Synergistic with opioids!! = ↑ resp. depression
-Bronchodilator effects = GOOD
Propofol: Adverse Effects
Prolonged Gtt’s can cause:
‣Hepatocellular injury
‣ PROPOFOL INFUSION SYNDROME
PRIS: What is it
PROPOFOL SYNDROME:
‣ Gtt’s > 75 mcg/mg/min for > 24 hrs
‣ S/sx: Lactic acidoses, Brady-dysrhthmias, Rhabdo.
‣ SEVERE refractory brady in PEDS
‣ DX: ABG and serum lactate
‣ Reversible in early stages
‣ Cardiogenic shock → ECMO
