Effect of subcutaneous G-CSF injectate volume on drug efficacy, site complications and client comfort

Recombinant granulocyte colony-stimulating factor (G-CSF) decreases the incidence, severity and duration of chemotherapy-induced neutropenia. The recommended dose frequently exceeds 1.0 ml in volume and is commonly escalated to the next available vial volume of 1.6 ml. There are no research-based recommendations in the literature regarding the maximum volume of G-CSF injectate to be given in a single subcutaneous site. Most nursing texts limit the recommended volume of injectate for a subcutaneous injection of any medication to 1.0 ml, while a few others posit that the maximum amount that can be comfortably absorbed from one site is 2.0 ml. The purpose of this study was to determine the effect of administering 1.6 ml (480 mcgm) doses of G-CSF in one subcutaneous injection or two injections of 0.8 ml each. Women who received hemopoietic rescue following high dose chemotherapy for breast cancer were randomized into an experimental group who received one injection per 480 mcgm dose and a control group who received two injections per 480 mcgm dose. All protocol doses were administered by research associate nurses who were trained in a standardized injection technique. Subjects were observed for differences in: (1) the number of days post-transplant until the absolute neutrophil count returned to 1000/mm$\backslash sp3,$ (2) the incidence and surface area in mm$\backslash sp2$ of site complications 72 hours following the dose and (3) scores on Tursky's Quantified Pain Descriptor instrument immediately following the injection(s). Age, race, amount of subcutaneous tissue at injection sites, medical treatment, research associate administering the dose, daily platelet counts, and analgesics received within 6 hours prior to the G-CSF dose were also recorded as potential covariates. Data reduction was achieved with principal components analysis of these covariates, followed by multivariate analysis of covariance, utilizing three component scores as covariates. The covariates did not significantly correlate with the dependent variables in either the univariate or multivariate setting. No significant difference was found between the two groups in neutrophil recovery time, the frequency or size of site complications or the intensity, reaction or sensation of discomfort reported.