Purchase this article with an account.
M. Timmermann, H. Gerding; How Precise Is the Dose When We Are Injecting Ranibizumab?. Invest. Ophthalmol. Vis. Sci. 2009;50(13):1895.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To analyze the amount of actually injected intravitreal ranibizumab (Lucentis®) in patients enrolled in a clinical routine treatment with a target dosage of 0.5 mg.
The amount of injected ranibizumab was evaluated by weighting the application syringes immediately before and after intravitreal injection under sterile conditions with a modified high resolution weight scale. The measurement procedure was evaluated and standardized previously. Measured weight data was divided by the density factor of ranibizumab solution (D = 1.04). Results of two surgeons (S1 and S2) were analyzed each using two different syringes (standard Lucentis® 1.0 ml syringe (Sy1.0) and 0.5 ml syringes (Sy0.5)) in a randomized order.
The mean dose of all injections was 0.497 +/- 0.099 mg (median: 0.48 mg, range: 0.23-0.90 mg) of ranibizumab (n = 484). In 150 of 484 (31 %) injections the difference between intended and measured dose was ≥20 %. Significant differences of the average dose were neither found comparing the two syringes (Sy1.0: mean 0.498 +/- 0.102 mg, median 0.480 mg, n=335; Sy0.5: mean 0.496 +/- 0.092 mg, median 0.480 mg, n=149) nor comparing the results of both surgeons (S1: mean 0.497 +/- 0.100 mg, median 0.480; S2: mean 0.497 +/- 0.095, median 0.480). In 31.6 % of injections with Sy1.0 (229 of 335) and 29.5 % with Sy0.5 (105 of 149) the injection result differed by ≥ 20 % from the target dosage. The use of Sy0.5 did not decrease the proportion of injections ≥20 % from the target of S1 whereas S2 yielded a significant improvement (p<0.05).
The results of this study demonstrate that the use of standard syringes for the injection of ranibizumab is leading to a relatively high proportion of outliers (≥ 20 %) from the target dosage. For future studies and clinical use it seems to be recommendable to perform injections with more precise syringes.
This PDF is available to Subscribers Only