Venous blood gas parameters, electrolytes, glucose and lactate concentration in sick neonatal foals: Direct venipuncture versus push-pull technique.

Abstract

Blood collection by indwelling intravenous catheter (IVC) avoids repeated venipuncture, which could cause thrombophlebitis risk, anxiety and pain in patients. To compare blood gas parameters, electrolytes, glucose, lactate and haematocrit concentration obtained from venous blood samples collected via a jugular IVC by push-pull (PP) technique to those obtained by venipuncture in hospitalised foals, at the time of catheter placement (T0) and 24hours after the beginning of intravenous therapy (T24). Prospective observational study. Paired blood samples were drawn from hospitalised foals at T0 and T24. In each foal, one venous blood sample was collected via IVC by the following PP technique: 2.4mL of blood was aspirated and immediately reinfused through the catheter three times consecutively, then 1mL of blood was collected using a 1mL heparinised syringe. Thereafter, another sample was collected by direct venipuncture of the contralateral jugular vein, with an identical 1mL heparinised syringe, with a 1-inch, 20-G needle. All samples were analysed with an automated blood gas analyser within 10minutes of collection. The agreement between the two techniques was assessed by Bland-Altman analysis and intraclass correlation coefficient (ICC). The level of agreement of blood gas values obtained by the two different techniques was high with very small bias and clinically acceptable ICC (>0.907 at T0; >0.794 at T24) for all variables, except for haematocrit (bias -3.52 at T0; -2.44 at T24) and PvO2 at T0 and T24 (ICC 0.669 and 0.733, respectively). Potential sub-clinical catheter-related complications were not investigated by ultrasound or bacterial culture of the catheter; short duration of the study. PP technique appears to be acceptable for collection of blood samples for venous blood gas parameters, as well as electrolytes, glucose and lactate in sick neonatal foals.