Lag times to steady state drug delivery by continuous intravenous infusion: direct comparison of peristaltic and syringe pump performance identifies contributions from infusion system dead volume and pump startup characteristics.

Time lags between the initiation of a continuous drug infusion and achievement of a steady state delivery rate present an important safety concern. At least 3 factors contribute to these time lags: (1) dead volume size, (2) the ratio between total system flow and dead volume, and (3) startup delay. While clinicians employ both peristaltic pumps and syringe pumps to propel infusions, there has been no head-to-head comparison of drug delivery between commercially available infusion pumps with these distinct propulsion mechanisms. We quantified the delivery of a model drug by peristaltic and syringe pumps at clinically relevant flow rates using spectrophotometric absorbance. Delivery curves were modeled and compared, and the time required to reach 5% (T5), 50% (T50), and 95% (T95) of the intended delivery rate was reported. The ability to overcome the combined effects of startup delay and dead volume differed between syringe and peristaltic pumps. T5, T50, and T95 were shorter for the peristaltic pump at higher flow rates. T50 and T95 were shorter for the syringe pump at lower flow rates. The ability to overcome the effects of dead volume was overall similar between the syringe and peristaltic pumps, as was the response to consecutive changes in drug infusion rates. Startup delay and dead volume in carrier-based infusion systems cause substantial time lags to reaching intended delivery rates. Peristaltic and syringe pumps are similarly susceptible to dead volume effects. Startup performance differed between peristaltic and syringe pumps; their relative performance may be dependent on flow rate.