From the Guidelines
A 70 kg patient can safely receive up to 56 mL of 0.25% bupivacaine. This calculation is based on the maximum recommended dose of bupivacaine, which is 2 mg/kg 1. For a 70 kg patient, this equals 140 mg of bupivacaine (70 kg × 2 mg/kg). Since 0.25% bupivacaine contains 2.5 mg of bupivacaine per mL, dividing the maximum dose by the concentration gives us 140 mg ÷ 2.5 mg/mL = 56 mL.
Key considerations for the administration of bupivacaine include:
- Monitoring for signs of local anesthetic toxicity, including perioral numbness, metallic taste, tinnitus, seizures, and cardiovascular depression.
- The actual volume used clinically is often less than the maximum and depends on the specific procedure and anatomical location.
- The use of bupivacaine should be guided by the principles of minimizing risk while maximizing pain control, as outlined in guidelines for the management of pleural infection 1.
It is essential to note that the maximum safe dose of bupivacaine can vary depending on factors such as the presence of epinephrine in the solution and the patient's overall health status. However, based on the provided evidence 1, the recommended maximum dose of 2 mg/kg is the most relevant guideline for this scenario.
From the FDA Drug Label
The duration of anesthesia with Bupivacaine Hydrochloride is such that for most indications, a single dose is sufficient Maximum dosage limit must be individualized in each case after evaluating the size and physical status of the patient, as well as the usual rate of systemic absorption from a particular injection site Most experience to date is with single doses of Bupivacaine Hydrochloride up to 225 mg with epinephrine 1:200,000 and 175 mg without epinephrine; more or less drug may be used depending on individualization of each case.
The maximum dose of bupivacaine is 225 mg with epinephrine and 175 mg without epinephrine. To calculate the volume of 0.25% bupivacaine that can be administered, we need to consider the maximum dose.
- 0.25% bupivacaine is equivalent to 2.5 mg/mL.
- The maximum dose without epinephrine is 175 mg.
- The volume of 0.25% bupivacaine that can be administered is 175 mg / 2.5 mg/mL = 70 mL. However, this calculation does not take into account the patient's weight. Since the label does not provide a clear dosage based on weight, a conservative approach would be to consider the maximum dose as a guideline. For a 70 kg patient, the dose should be individualized, but the label does not provide a specific formula for weight-based dosing. Therefore, the maximum volume of 0.25% bupivacaine that can be administered to a 70 kg patient cannot be determined with certainty based on the provided information 2.
From the Research
Maximum Recommended Dose of Bupivacaine
The maximum recommended dose of bupivacaine is dependent on various factors, including the technique of administration and the patient's body weight.
- For a 70 kg patient, the maximum recommended dose of bupivacaine is 150 mg for subcutaneous injection, injection in regions of high absorption, and single injection (perineural, e.g. plexus) 3.
- The dose can be higher for techniques of protracted injection, with a maximum recommended dose of 200 mg 3.
- It is also important to note that the maximum recommended dose should be adjusted based on the patient's individual characteristics, such as body weight and condition 3, 4.
Calculation of Maximum Volume of 0.25% Bupivacaine
To calculate the maximum volume of 0.25% bupivacaine that a 70 kg patient can receive, we need to divide the maximum recommended dose by the concentration of the solution.
- The concentration of 0.25% bupivacaine is 2.5 mg/mL.
- Assuming a maximum recommended dose of 150 mg, the maximum volume of 0.25% bupivacaine would be 150 mg / 2.5 mg/mL = 60 mL 3.
- However, it is essential to consider the specific technique of administration and the patient's individual characteristics when determining the maximum safe dose 3, 4.