Preparing Bupivacaine Solution Without Steroids for Field Block
For field block anesthesia, use bupivacaine 0.25% solution without any steroid additives, administered at a dose of 0.2-0.5 ml/kg (maximum 2.5 mg/kg), ensuring the total volume does not exceed safe systemic absorption limits. 1, 2
Solution Preparation
Standard Concentration and Formulation
- Use commercially available bupivacaine 0.25% (2.5 mg/mL) solution directly from the vial without any additives for field block procedures 1, 3
- Bupivacaine 0.5% (5 mg/mL) can be diluted with preservative-free normal saline to achieve 0.25% concentration if needed 3
- Do not add corticosteroids - the question specifically requests a steroid-free solution, and current guidelines for field blocks do not recommend steroid addition 1
Volume Calculations
- Maximum safe dose: 2.5 mg/kg of bupivacaine 0.25%, which equals 1 ml/kg of the 0.25% solution 1, 2, 4
- For a 70 kg adult: maximum 175 mg total dose = 70 mL of 0.25% solution 2
- Always calculate dose based on ideal body weight in obese patients to avoid overdosing 2
Optional Adjuvants (Non-Steroid)
Epinephrine Addition
- Epinephrine 1:200,000 (5 mcg/mL) may be added to prolong duration and reduce systemic absorption 3
- Do not autoclave solutions containing epinephrine - they must be protected from light and used fresh 3
- Mix by adding 0.1 mL of 1:1000 epinephrine to each 20 mL of bupivacaine solution to achieve 1:200,000 concentration 3
Preservative-Free Clonidine
- Clonidine 1-2 mcg/kg can be added to enhance analgesia duration without steroids 1
- This adjuvant is particularly useful for peripheral nerve blocks and field blocks requiring extended analgesia 1
Critical Safety Protocols
Solution Handling
- Solutions without epinephrine may be autoclaved at 15-pound pressure, 121°C for 15 minutes if sterilization is needed 3
- Store at 20-25°C (68-77°F); excursions permitted between 15-30°C 3
- Discard solution if color is pinkish or darker than slightly yellow, or if precipitate is present 3
Administration Precautions
- Always aspirate before injection to avoid intravascular administration 3
- Inject incrementally with frequent aspiration, especially in highly vascular areas 2, 4
- Have lipid emulsion (20% Intralipid) immediately available for treatment of local anesthetic systemic toxicity (LAST) 5
Common Pitfalls to Avoid
Concentration Errors
- Do not confuse 0.25% with 0.5% solutions - this represents a 2-fold dosing error 3
- Verify concentration on the vial label before drawing up solution 3
- Never exceed 2.5 mg/kg total dose when using 0.25% solution for infiltration 2, 4
Inappropriate Additives
- Avoid adding steroids (dexamethasone, methylprednisolone) as they are not indicated for simple field blocks and may increase infection risk 1
- Do not use solutions containing preservatives (methylparaben) for neuraxial or large-volume peripheral blocks 3
- Multi-dose vials contain methylparaben 1 mg/mL as preservative - use single-dose vials for neuraxial techniques 3
Monitoring Requirements
- Monitor for early signs of systemic toxicity: perioral numbness, metallic taste, tinnitus, dizziness 5
- Cardiovascular toxicity with bupivacaine is particularly resistant to standard resuscitation - have lipid emulsion ready 5
- Reduce dose in elderly, debilitated, or patients with significant cardiac or hepatic disease 2