Post Your Cases > LAST following femoral nerve block in a patient with severe hypoalbuminemia
An 85-year-old patient showed LAST following an ultrasound-guided, neuro-stimulated femoral nerve block with a solution of ropivacaine + lidocaine. Her lab tests showed albuminemia of 1.6 g/dl as positive data. Intravascular injection was avoided by administering the lowest effective dose, aspirating with the syringe prior to each injection and incrementally injecting 3 to 5 ml, every 15 seconds while observing through ultrasound both the needle and local anesthetic dispersion. After blocking, vital-sign monitoring system evidenced a 70% O2 desaturation and bradycardia. She was disoriented and presented severe signs of respiratory difficulty. Hemodynamic support and orotracheal intubation were performed. LAST was identified. Two boluses of 1.5 ml/kg of 20% intravenous lipid emulsion were given. There were not signs of sensorium recovery but there was not cardiovascular collapse either. She remained intubated in the ICU and then extubated with sensorium restitution. We interpreted LAST as secondary to the hypoproteinemia presented by the patient and assumed that the low levels of albumin had led to an increase in the free fraction of local anesthetics and thus to their deleterious effects. Neurotoxicity observed was not the standard that LAST can produce (there were no convulsions). Intoxication stemmed from the patient’s hypoproteinemia, which is not a common cause. It is important to check proteinogram to detect hypoalbuminemia prior to performing a peripheral nerve block.
Thank you for your response. The patient weighed 70 kilograms. Her only comorbidity was hypertension. We administered a solution of 0.525% ropivacaine + 0.6% lidocaine, total volume 15 ml.
Intravascular injection was avoided by administering the lowest effective dose, aspirating with the syringe prior to each injection and incrementally injecting 3 to 5 ml, every 15 seconds while observing through ultrasound both the needle and local anesthetic dispersion.
After blocking, vital-sign monitoring system evidenced a 70% O2 desaturation and bradycardia. She was disoriented and presented severe signs of respiratory difficulty.
Hemodynamic support and orotracheal intubation were performed. LAST was identified. Two boluses of 1.5 ml/kg of 20% intravenous lipid emulsion were given. There were not signs of sensorium recovery but there was not cardiovascular collapse either. She remained intubated in the ICU and then extubated with sensorium restitution.
We interpreted LAST as secondary to the hypoproteinemia presented by the patient and assumed that the low levels of albumin had led to an increase in the free fraction of local anesthetics and thus to their deleterious effects.
Neurotoxicity observed was not the standard that LAST can produce (there were no convulsions). Intoxication stemmed from the patient’s hypoproteinemia, which is not a common cause.
It is important to check proteinogram to detect hypoalbuminemia prior to performing a peripheral nerve block.