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Correspondence  |   November 2003
The Rapid Infusion System: Error of the Infused Volume Readout Caused by the Kinking of a Tube
Author Affiliations & Notes
  • Matthias Hartmann, M.D.
    *
  • *Hein-rich Heine University, Düsseldorf, Germany.
Article Information
Correspondence
Correspondence   |   November 2003
The Rapid Infusion System: Error of the Infused Volume Readout Caused by the Kinking of a Tube
Anesthesiology 11 2003, Vol.99, 1246. doi:
Anesthesiology 11 2003, Vol.99, 1246. doi:
To the Editor:—
The Rapid Infusion System (RIS) (Hemonetics, Braintree, Massachusetts) is a device designed to deliver blood products and other fluids at precise flow rates up to 1.5 l/min. An important feature of the RIS is the readout of the total infused volume. We present a case in which kinking of a RIS-tube resulted in the inability to infuse fluids and led to erroneously high infusion volume readout without alarms.
A 64-yr-old man presented for thoracoabdominal aortic aneurysm repair. The initial course of surgery was uneventful, and blood loss of 16 l (as judged from cell saver reading) was substituted via  the RIS. Later in the procedure, however, the patient developed marked hypovolemia, although the infusion rate setting (1.5 l/min) and corresponding infused volume readout of the RIS by far exceeded the actual rate of blood loss (about 200 ml/min). Inspection of the RIS revealed that the reservoir level did not decrease according to the infusion rate and that infusion pressure was far below the expected value. Finally, we noticed a kinking of the tube located between the heat exchanger and roller pump, which prevented fluid inflow into the roller pump (fig. 1). After removing the kink, infusion pressure correlated with infusion rate, reservoir level decreased appropriately, and hypovolemia resolved.
Fig. 1. Schema of the Rapid Infusion System (RIS) and photography showing the kinking of the tube. Inflow of fluids from the reservoir to the roller pump was interrupted; thus, no fluid was infused. The total infusion volume readout, however, steadily increased according to the chosen infusion rate because this value is obtained from the rotation of the roller pump. Although the RIS is featured with various safety devices, an occlusion of the tube proximal to the roller pump does not result in an alarm.
Fig. 1. Schema of the Rapid Infusion System (RIS) and photography showing the kinking of the tube. Inflow of fluids from the reservoir to the roller pump was interrupted; thus, no fluid was infused. The total infusion volume readout, however, steadily increased according to the chosen infusion rate because this value is obtained from the rotation of the roller pump. Although the RIS is featured with various safety devices, an occlusion of the tube proximal to the roller pump does not result in an alarm.
Fig. 1. Schema of the Rapid Infusion System (RIS) and photography showing the kinking of the tube. Inflow of fluids from the reservoir to the roller pump was interrupted; thus, no fluid was infused. The total infusion volume readout, however, steadily increased according to the chosen infusion rate because this value is obtained from the rotation of the roller pump. Although the RIS is featured with various safety devices, an occlusion of the tube proximal to the roller pump does not result in an alarm.
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The case demonstrates that the infusion volume readout displays erroneous high values if an obstruction of the roller pump inflow occurs. The false measure is due to the infused volume readout being obtained by the rotation of the roller pump rather than by direct flow or volume determination. The malfunction occurred after an uneventful initial surgical phase. Most likely, warming of the tube had resulted in kinking. Two additional cases associated with the use of the RIS have been described in the literature: the connection of one of the infusion lines to the reservoir, and the incorrect positioning of the recirculation line in the respective clamp. 1,2 Similar to the present case, the real infusion rate was much lower than that displayed by the infused volume readout.
The RIS is a valuable tool for the management of massive blood loss. It is, however, important to realize that the infused volume readout is a measure of roller pump rotation, which might not always be identical to the fluid volume applied to the patient. Careful observation of the infused volume readout, infusion pressure, volume added to the reservoir, and assembly of the apparatus, as well as the hemodynamic effects of infusion, is mandatory for the early detection of malfunctions.
References
Kempen PM, Hudson ME, Planinsic RM: The Rapid Infusion System: User error in tubing connection mimicking severe hemorrhage. A nesthesiology 2000; 93: 278–9Kempen, PM Hudson, ME Planinsic, RM
Lustik SJ, Chhibber AK: Unintentional recirculation with the rapid infusion system [letter]. Anesth Analg 1999; 89: 1069Lustik, SJ Chhibber, AK
Fig. 1. Schema of the Rapid Infusion System (RIS) and photography showing the kinking of the tube. Inflow of fluids from the reservoir to the roller pump was interrupted; thus, no fluid was infused. The total infusion volume readout, however, steadily increased according to the chosen infusion rate because this value is obtained from the rotation of the roller pump. Although the RIS is featured with various safety devices, an occlusion of the tube proximal to the roller pump does not result in an alarm.
Fig. 1. Schema of the Rapid Infusion System (RIS) and photography showing the kinking of the tube. Inflow of fluids from the reservoir to the roller pump was interrupted; thus, no fluid was infused. The total infusion volume readout, however, steadily increased according to the chosen infusion rate because this value is obtained from the rotation of the roller pump. Although the RIS is featured with various safety devices, an occlusion of the tube proximal to the roller pump does not result in an alarm.
Fig. 1. Schema of the Rapid Infusion System (RIS) and photography showing the kinking of the tube. Inflow of fluids from the reservoir to the roller pump was interrupted; thus, no fluid was infused. The total infusion volume readout, however, steadily increased according to the chosen infusion rate because this value is obtained from the rotation of the roller pump. Although the RIS is featured with various safety devices, an occlusion of the tube proximal to the roller pump does not result in an alarm.
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