Study points to a practical way to reduce venipuncture in dogs: full analysis

Version 2 — Full analysis

Hospitalized dogs often need repeat bloodwork, and that usually means repeat venipuncture. New research published in JAVMA points to a practical alternative: a push-pull sampling protocol using a peripheral IV catheter that appears to deliver clinically usable CBC and biochemistry results while reducing the need for additional needle sticks. In a prospective study of 70 dogs, investigators found that samples collected through the catheter tracked closely with venipuncture samples, both at placement and after at least 24 hours of hospitalization with IV fluids and medications. (researchgate.net)

The idea itself isn’t entirely new. Earlier work from Penn Vet, published in 2017, found that push-pull catheter sampling in dogs produced no clinically relevant differences for blood gases, electrolytes, and related measures compared with venipuncture, while also avoiding the need to discard a presample. Researchers and clinicians framed that as a way to reduce both blood loss and repeated needle trauma, particularly in patients under anesthesia or requiring frequent monitoring. (eurekalert.org)

What makes the newer study more relevant to day-to-day inpatient care is the setting. According to the study abstract and dissertation summary from the University of Prince Edward Island, the dogs were actual hospitalized patients receiving IV fluid therapy, not just perioperative cases at the time of catheter placement. Investigators enrolled dogs weighing at least 10 kg, excluded those with suspected coagulopathy, clinically relevant anemia, or thrombocytopenia, and compared paired venipuncture and peripheral IV catheter samples at admission and again after a minimum of 24 hours. The researchers reported that although some differences reached statistical significance, they were not clinically relevant for decision-making, with leukogram indices more likely to show discordance than other measures. (researchgate.net)

That distinction is important because catheter-based sampling has long raised concerns about dilution, contamination, hemolysis, and analyte distortion after fluids or drugs run through the line. Clinician’s Brief has previously noted that if a catheter is used for repeated blood sampling, it should ideally be dedicated to that purpose, since shared use with IV fluids and medications can skew some results, particularly glucose, potassium, and venous blood gas values. The same review also highlights the tradeoffs of repeated venipuncture in critically ill patients, including hematoma development, iatrogenic anemia, infection, and discomfort. (cliniciansbrief.com)

The broader expert perspective is that this is less about replacing venipuncture in every circumstance and more about adding another validated option. The Penn Vet team’s earlier comments emphasized convenience, patient comfort, and preservation of a closed system, while the newer study extends that logic into the hospitalized-dog population. Taken together, the evidence suggests the push-pull method may be most useful when teams need serial monitoring and already have a functioning peripheral catheter in place. (eurekalert.org)

Why it matters: For veterinary professionals, this is a workflow story as much as a clinical one. A reliable catheter-based sampling method could reduce restraint events, lower stress for canine patients and staff, preserve veins in dogs with difficult access, and limit cumulative blood loss over multi-day stays. It may also help practices standardize inpatient monitoring protocols, especially in emergency and critical care settings. At the same time, the study’s exclusions matter: these findings shouldn’t be overgeneralized to smaller dogs, patients with coagulopathy, marked anemia, thrombocytopenia, or every analyte under every catheter-use condition. (researchgate.net)

There are still practical questions for hospitals to work through, including staff training, line-handling protocols, and which tests should still default to fresh venipuncture. Leukogram indices may warrant extra caution, based on the reported discordance, and practices will likely want clear SOPs around flush volumes, timing relative to drug administration, and sample rejection criteria. Those operational details will determine whether the method improves care in the real world, not just on paper. This is an inference based on the study findings and existing catheter-management guidance. (researchgate.net)

What to watch: The next step is likely broader validation, including smaller dogs, longer catheter dwell times, and clearer guidance on which analytes are most dependable when samples are pulled from shared peripheral lines rather than dedicated sampling catheters. (researchgate.net)