|
| Sedative induction agents used in RSI |
| Agent |
IV Dose |
Onset |
Duration |
| Thiopental |
3 - 5 mg/kg |
10 - 40 secs |
10 - 20 mins |
| Methohexital |
1.5 mg/kg |
30 - 60 secs |
5 - 10 mins |
| Etomidate |
0.3 mg/kg |
30 - 45 secs |
10 - 20 mins |
| Propofol |
1 - 2 mg/kg |
10 - 30 secs |
8 - 10 mins |
| Ketamine |
1 - 2 mg/kg |
30 - 60 secs |
5 - 20 mins |
| Midazolam |
0.1 - 0.3 mg/kg |
2 - 3 mins |
20 - 30 mins |
| Sedative induction agents used in RSI - advantages, disadvantages and contra-indications |
| Agent |
Advantages |
Disadvantages |
Contra-indications |
| Thiopental |
- rapid onset
- brief duration
- decreases ICP
- anticonvulsant
|
- decreases blood pressure
- myocardial depression
- respiratory depression
- histamine release
- no analgesic effect
|
- hypotensive patient
- asthmatic patient
- porphyria
|
| Methohexital |
- very rapid onset
- very short duration
- decreases ICP
|
- decreases blood pressure
- respiratory depression
- seizures (rare)
- hypertonus/hiccuping
- laryngospasm
- no analgesic effect
|
- hypotensive patient
- ? seizure disorder
- porphyria
|
| Etomidate |
- no deleterious effect on blood pressure
- minimal depression of respiration
- decreases ICP and IOP
|
- myoclonic movements
- seizures
- hiccups
- nausea/vomiting
- decreases steroid synthesis
- minor pain on injection
- no analgesic effect
|
- ? focal seizure disorder
- adrenal insufficiency
- should not be used as a continuous IV sedating agent, because it depresses steroid synthesis
|
| Propofol |
- decreases ICP
- titratable - useful for maintenance sedation
- anti-emetic
- anti-convulsant
|
- decreases blood pressure
- myocardial depression
- respiratory depression
- myoclonic movements
- minor pain on injection
- rare bronchospasm
- no analgesic effect
|
- hypotensive patient
- ? asthmatic patient
|
| Ketamine |
- "dissociative" anesthesia without impairing airway reflexes
- analgesia ++
- amnesia
- bronchodilator
- no decrease in blood pressure - useful in hypotensive patients
- no significant respiratory depression
|
- increases ICP
- ? minimally increases IOP
- increases airway secretions
- laryngospasm
- increases blood pressure
- increases heart rate
- increases muscle tone
- nausea/vomiting
- emergence reactions
|
- uncontrolled hypertension
- increased ICP
- penetrating eye injury
- glaucoma
- acute URI
- ? CAD/CHF
- history of psychosis
- thyroid storm
|
| Midazolam |
- amnesia ++
- anti-convulsant
|
- delayed onset
- inconsistent effect
- respiratory depression
- hypotension - variable and dose-dependent
|
|
| Sedative induction agents suitable for different clinical scenarios |
| Clinical scenario |
Suitable options (in order of preference) |
| Normotensive/euvolemic |
Etomidate, thiopental, propofol, midazolam |
| Mild hypotension + head injury |
Etomidate, thiopental, propofol, midazolam |
| Mild hypotension + no head injury |
Etomidate, ketamine, low dose midazolam |
| Severe hypotension |
Ketamine, half-dose etomidate (0.15mg/kg), very low dose midazolam (0.05 - 0.1mg/kg) |
| Status asthmaticus |
Ketamine, etomidate, propofol |
| Status epilepticus |
Thiopental, propofol, midazolam |
| Isolated head injury |
Etomidate, thiopental, propofol |
| Cardiogenic pulmonary edema |
Etomidate, low dose midazolam |
| Muscle relaxants used in RSI |
| Agent |
IV Drug dose |
Time to intubation |
Duration |
| Succinylcholine |
1.5 mg/kg
(peds - 2 mg/kg) |
45 - 60 secs |
6 - 12 mins |
| Rocuronium |
1.0 mg/kg |
45 - 75 secs |
30 - 60 mins |
| Rapacuronium |
1.5 mg/kg
(peds - 2 mg/kg if < 12 years) |
45 - 75 secs |
20 - 30 mins
(8 - 10 mins if reversed with 0.05mg/kg of neostigmine) |
| Muscle relaxants used in RSI - advantages, disadvantages and contra-indications |
| Agent |
Advantages |
Disadvantages |
Contra-indications |
| Succinylcholine |
- rapid onset
- short duration
- reliable
|
- bradyarrhythmias
- increases serum potassium
- increases intragastric pressure (mild)
- increases IOP (minimal)
- increases ICP (? significance)
- masseter spasm (rare)
- malignant hyperthermia (rare)
- fasciculation-induced muscle pain
- prolonged effect in plasma pseudocholinesterase deficiency states
- hyperkalemia-induced cardiac arrest in children with undiagnosed myopathy (very rare)
|
- difficult airway and insecurity about the ability to sucessfully BVM the patient
- family or personal history of malignant hyperthermia
- known hyperkalemia
- certain chronic muscle dystrophies, prior spinal cord injury, prior strokes, any demyelinating diseases
- pre-existing tissue injury > 3 days prior to RSI
- burns > 24 hours prior to RSI
- increased ICP
- ? head injury (relative)
- ? open globe injury (relative)
- renal failure with hyperkalemia (absolute)
- renal failure without hyperkalemia (relative)
|
| Rocuronium |
- no effect on serum potassium
- no bradycardia
- no fasciculation
|
- slightly delayed onset
- long duration
- tachycardia - mild vagolytic effect
|
- difficult airway and insecurity about the ability to sucessfully BVM the patient
|
| Rapacuronium |
- no effect on serum potassium
- no bradycardia
- no fasciculation
|
- longer duration (duration can be decreased ~ 50% with neostigmine - 0.05 mg/kg)
- releases histamine
- new drug - experience is still limited
|
- difficult airway and insecurity about the ability to sucessfully BVM the patient
- ? asthma
|
| Post-intubation maintenance sedation |
| Sedative |
Intermittent bolus (mg/kg) |
Infusion (mcg/kg/hour) |
| Diazepam |
0.1 - 0.15 |
|
| Lorazepam |
0.05 - 0.1 |
|
| Midazolam |
0.05 - 0.1 |
|
| Propofol |
1 - 1.5 |
10 - 30 |
|
