Ultrasound capsules
Local anesthetics
Local anesthetics
Lidocaine without epinephrine
max 4mg/kg ad total max of 300mg
1% = 0.4mL/kg ad max of 30mL
1% = 10mg/mL
Bupivacaine without epinephrine
max 2.5mg/kg ad total max of 150mg
0.5% = 0.5mL/kg ad max of 30mL
0.5% = 5mg/mL
Ropivacaine without epinephrine
max 3mg/kg ad total max of 150mg
0.5% = 0.6mL/kg ad max of 30mL
0.5% = 5mg/mL
Additional information:
It is important to use the minimum effective dose
It is essential to have a 20% lipid emulsion available
Personally, I never give the maximum dose calculated with the patient's weight.
I subtract:
5mL of the maximum calculated dose.
eg: 66kg --> 33 mL of ropivacaine 0.5% --> I will use 28 mL.
Even more important if it is an elderly person where my maximum dose becomes 25mL (for the local anesthetics above).
So if the patient above is actually an 88 year old patient even though my cushion brings me to 28 mL, I will use 25 mL.
5mL if pregnant (and my maximum dose becomes 25mL)
5mL if severe comorbidities (and my maximum dose becomes 25mL)
Therefore, if a polymorbid elderly person requires a block, their weight is 54 kg and I use ropivacaine 0.5%.
The maximum dose for his weight is 27mL of ropivacaine 0.5%.
I subtract 5mL due to age and 5mL due to comorbidities --> 17mL which I will dilute as needed for the needs of the operating room.
The goal is to avoid LAST by absorption at all costs.
Adjuvant - Dexamethasone
Although based on moderate evidence, the addition of dexamethasone can prolong the analgesic effect of the nerve block and reduce opioid consumption.
Dose : 4-8 mg mixed with your ropivacaine or bupivacaine syringes OR 8 mg IV (more systemic effect but less complex since no need to mix).
Formulation to use: Single-dose formulations are preferred. These do not contain preservatives, unlike multi-dose formulations, which can be toxic to nerves.