What volume of normal saline (NS) should Thiopental Sodium be diluted in?

Thiopental Sodium Dilution in Normal Saline

Thiopental Sodium (Penthomin) should be diluted in 10 mL of normal saline (NS) for intravenous administration.

Dilution Guidelines

Thiopental sodium is a barbiturate anesthetic agent that requires proper dilution before administration. Based on the available evidence, the following dilution protocol is recommended:

• Standard dilution: 10 mL of normal saline
• Concentration: This creates an appropriate concentration for IV administration
• Administration rate: Should be given slowly to avoid complications

Administration Considerations

When administering diluted thiopental:

1. Avoid rapid administration: Rapid IV administration may precipitate seizures 1
2. Monitor for adverse effects:
   • Sedation and respiratory depression
   • Hypotension
   • Paradoxical excitement or agitation

Clinical Pearls and Cautions

• Dosing: Standard IV/IO dosing is 0.2-0.4 mg/kg (maximum: 20 mg) for rapid sequence intubation (RSI) 1
• Advantages: Will lower intracranial pressure (ICP) without usually lowering blood pressure, making it a desirable agent for patients with head injury, multisystem trauma, or hypotension 1
• Onset and duration: Rapid onset with duration of approximately 10-15 minutes
• Limitations: Does not have analgesic properties

Potential Adverse Effects

• May cause brief myoclonic activity (hiccups, cough, twitching)
• May exacerbate focal seizure disorders
• Can cause transient adrenal suppression (though not clinically significant)
• May cause pain on injection (can be reduced with proper dilution)

Infection Risk Considerations

Thiopental solutions should be prepared with strict aseptic technique. Unlike propofol, thiopental has some inherent antimicrobial properties, with studies showing it can reduce bacterial colony-forming units over time 2. However, proper sterile technique remains essential.

Laboratory Interference

Be aware that thiopental treatment can result in falsely elevated serum sodium levels on certain laboratory devices, which could lead to inappropriate clinical decisions regarding fluid management 3. If sodium levels appear unusually elevated during thiopental administration, confirm with point-of-care testing.

Special Considerations

For patients requiring continuous infusion or higher doses, appropriate monitoring for respiratory depression and cardiovascular effects is essential. Always have resuscitation equipment readily available when administering thiopental.