Are peristaltic pumps as reliable as syringe pumps for metabolic research? assessment of accuracy, precision, and metabolic kinetics

Syringe pumps are traditionally used to infuse tracers in metabolic research because they are perceived to be more accurate and precise than peristaltic pumps. This study evaluated the accuracy (actual v programmed infusion rate) and precision (reproducibility of infusion) of a peristaltic pump (Gemini PC 2; IMED, San Diego, CA) and a syringe pump (Model 22; Harvard Apparatus, Natick, MA) for metabolic research. In one protocol, saline delivery was measured in vitro in 5 trials at 4 flow rates: 3, 30, 150, and 300 mL/h. In the second protocol, basal glycerol rate of appearance (Ra) was determined in vivo in 5 women on 2 consecutive days. On day 1, [2-¹³C]glycerol was infused with 1 pump and [1,1,2,3,3-²H₅]glycerol with the other. On day 2, the opposite pattern was used. The accuracy of the 2 pumps was the same (error ∼2%). In addition, both the syringe and the peristaltic pumps were very precise, with coefficients of variation (CV) <1% at all flow rates. Glycerol Ra values were the same when tracer was infused with either a syringe or peristaltic pump on day 1 and day 2: 4.1 ± 1.7 (syringe pump) and 4.2 ± 1.9 (peristaltic pump) μmol·kg fat mass (FM) ^-1·min^-1 on day 1; 4.2 ± 1.2 (syringe pump) and 4.2 ± 1.3 (peristaltic pump) μmol·kg FM ^-1·min^-1 on day 2. These data demonstrate that both syringe and peristaltic pumps are very accurate and precise across a large range of flow rates. Moreover, the assessment of in vivo substrate kinetics in human subjects is the same when either pump is used to infuse isotope tracers.