ABSTRACT
OBJECTIVE: To compare mock drug deliveries to the proximal aorta during CPR after peripheral vs central i.v. administration when the mock drug is followed by different postinfusion flush volumes. METHODS: Delivery of indocyanine green (ICG) dye to the proximal aorta of an instrumented 20-kg canine cardiac arrest model was examined. The ICG administration (2.5 mg) preceded either a 2-mL or a 10-mL saline flush, for either a central or a peripheral i.v. route of dye administration. Five dogs each underwent three sets of the four possible route/flush-volume combinations in a stratified randomized order. Real-time dye-absorbance-vs-time curves, as sampled from the proximal aorta, modeled central-circulation drug delivery. Systolic and diastolic blood pressures (BPs) were monitored, and the absorbance-vs-time curve upstroke phases were used to estimate cardiac output during arrest. RESULTS: Times (mean +/- SD) to onset of dye appearance did not differ significantly between peripheral/10 mL (126 +/- 35 sec) and central/10 mL (108 +/- 35 sec), or between central/2 mL (123 +/- 31 sec) and central/10 mL. Times to onset of dye appearance did differ between peripheral/2 mL (161 +/- 70 sec) and central/10 mL [analysis of variance (ANOVA) p = 0.032]. Times to peak dye concentration did not differ significantly between peripheral/10 mL (230 +/- 88 sec) and either central/10 mL (202 +/- 88 sec) or central/2 mL (215 +/- 83 sec), but differed between peripheral/2 mL (326 +/- 134 sec) and every other route/flush-volume combination (ANOVA p = 0.009). Peak dye concentrations and systolic/diastolic BPs (averaging 23/10 for all route/flush-volume combinations) did not differ significantly between any route/flush-volume combinations. CONCLUSION: An adequately sized postinfusion crystalloid flush (0.5 mL/kg) permits peripherally administered model drug to reach the central circulation as quickly and in equivalent concentration as centrally administered drug during CPR in a canine cardiac arrest model.
