Flow rates of large animal fluid delivery systems used for high-volume crystalloid resuscitation.

The research was about determining the maximum flow rates of Intravenous (IV) catheters, extension sets and fluid administration sets used for high-volume crystalloid resuscitation in large animals. The outcomes showed flow rates ranging from 7.4 liters per hour to 51.2 liters per hour, with in vivo delivery in an adult horse measured 21% slower than in vitro rates.

Methods

• The study was conducted at a university veterinary teaching hospital, and it followed an in vitro experimental design.
• The researchers measured the maximum flow rates using combinations of 4 IV catheters (3 14-Ga and a single 10-Ga), 2 IV catheter extension sets (small bore and large bore), and 2 types of fluid administration sets (standard 2-lead large animal coiled IV set and nonpressurized 4-lead arthroscopic irrigation set).
• The catheter, extension sets, and administration sets were configured in 16 distinct arrangements.
• Flow rates were measured in triplicate using tap water flowing into an open receptacle.

Results

• Flow rates varied with the configuration of catheter, extension set and fluid administration used. The rates ranged from as low as 7.4 L/h with an over-the-wire 14-Ga catheter, small-bore extension, and coil set, to a high of 51.2 L/h using a 10-Ga catheter, no extension, and arthroscopic irrigation set.
• Between the large- and small-bore extension sets, flow rates increased from 1.3 to 8.9%.
• In vivo crystalloid delivery to an adult horse was found to be 21% slower at 9.1 L/h as compared to the in vitro measurements at 11.5 L/h.

Conclusions

• The study concluded that extremely high flow rates can be achieved in vitro using large-bore catheters and delivery systems.
• The need for flow rates greater than 50 L/h is not yet determined in a clinical setting.
• A notable takeaway was that the use of large-bore extension sets resulted in only a minimal increase in flow rate.