Use Of Extension Sets With Smiths Medical Infusion Pumps

Thursday April 09 2020

In line with recent FDA thinking regarding COVID-19, Smiths Medical is providing the following information about adding extension sets to infusion pump tubing to create length allowing the pumps to be placed outside patients’ rooms. This is a clinical decision that should consider the practice implications described by the Infusion Nurses Society (INS), Institute for Safe Medication Practices (ISMP) and Emergency Care Research Institute (ECRI) in the links below.

• Infusion Nurses Society (INS) – FAQ on this practice
• Institute for Safe Medication Practices (ISMP) – p. 3-4 sidebar on this topic
• ECRI- Considerations When Used with Long Extension Sets Outside Patient Rooms to Help Reduce Staff PPE Use

Additionally, Smiths Medical has published the “Factors to Consider When Selecting Infusion Disposables..” In general, there are many parameters that affect the accuracy of delivery of an infusion pump. This would include the viscosity of the drug, the height of the pump compared to the patient, the gauge and length of the vascular access device, the drug reservoir (syringe size and brand, bag, etc.), and the characteristics of the tubing between the pump and patient including, but not limited to, tubing bore, length, filters, and backcheck valves. These factors may also impact the functionality of the pump’s internal time to occlusion alarm performance. This information should be considered along with the attached information to consider when deciding to add length to pump tubing.

Mathematical modeling data demonstrating the use of micro- and small-bore extensions sets with our delivery sets has been conducted for the Medfusion^® 3500 and 4000 pumps with minimal degradation on accuracy, performance, and minimal nuisance alarms. Refer to the “Medfusion^® Back Pressure Calculation Table” provided with this letter for further details. These statements have not been evaluated by the FDA.

CADD^® pumps are designed to be used with a single extension set or a single administration set. There are several CADD^® administration sets that are over 10 feet long that may be suitable for locating the pump outside the room. Use with longer length extension sets such as MX20194 (20' x .046" ID) will increase back pressure by 50 mmHg at 150 mL/hr flowrate, which may impact delivery accuracy. When connecting multiple pumps to the same patient line, back pressure will increase further. Carefully monitor delivery under these circumstances and consider raising the pump or increasing flow rate to compensate.

Please contact your local Smiths Medical account manager or customer service representative with any additional questions. You may also visit Customer Services to leave a question and one of our customer service representatives will respond to you directly.

Medfusion^® Back Pressure Calculation Table

The Medfusion^® pump has a published accuracy of +/- 2% (not including syringe variation) at infusion back pressures of -100 mmHg to +300 mmHg. Per the predicted downstream back pressure calculations, the pump will maintain +/-2% accuracy with extended sets when placed at or above the infusion site based on the modeled data.

All calculations are done on a Medfusion^® pump with Saline in a 60 mL syringe delivered intravenously through a Jelco® 20G peripheral intravenous catheter (PIVC).
The following Smiths Medical extension sets are referenced in the table below:

• MX20194 – Small Bore Extension with Pinch Clamp, Male Leur Lock - 240" (609 cm) APV 6.5 mL
• MX448 – Small Bore Extension with Removable Slide Clamp, Male Luer Lock
• 536040 – Micro Bore Extension with Male Luer Lock, APV 0.3 mL, 61" (155 cm)

*Note predicted back pressure will differ based on combination of components including: Flow rate, vascular access device gauge, infusion extension set bore and length, and position of pump in relation to patient. Micro Bore tubing creates high back pressure than small or standard bore tubing.

Medfusion Model 4000 pump

Operation Model