Why does the total lidocaine dose matter more than the concentration printed on a bronchoscopy syringe?

Several administrations contributed to one total

Madan and colleagues ran a randomized pilot comparing 1% with 2% spray-as-you-go lignocaine, also called lidocaine, during endobronchial ultrasound-guided needle aspiration. Both groups also received pharyngeal spray and nebulized lignocaine, and additional topical dosing was permitted. Midazolam and fentanyl were used as part of the common sedation regimen.

Concentration describes strength per unit of volume

The mean cumulative lignocaine dose was 178.5 mg in the 1% group and 248.6 mg in the 2% group. The study did not find statistically significant differences in operator-rated cough or satisfaction. Those outcomes help describe the pilot, but they do not establish equal efficacy or equal safety across all bronchoscopies.

What a record review should reconstruct

Match each administration time to the formulation, volume and concentration. Include the initial spray, nebulized solution and subsequent doses in the same calculation where the record supports it. Compare that chronology with the symptoms or monitoring record. A single syringe label gives one input to that analysis and leaves the total exposure unresolved.

Source paper

Read the study at PubMed Central (PMC6219128).