|LETTER TO EDITOR
|Year : 2014 | Volume
| Issue : 6 | Page : 780-781
A technique to prevent overfilling of viewing chamber of intravenous infusion kit
Lovelesh Kakani, Surinder M Sharma, Rashmi C Mehta, Gurpreet Singh
Department of Anaesthesia, Medanta the Medicity, Gurgaon, Haryana, India
|Date of Web Publication||17-Dec-2014|
Dr. Gurpreet Singh
G330 A, 1st Floor, Sector 57, Sushant Lok 2, Gurgaon - 122 009, Haryana
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Kakani L, Sharma SM, Mehta RC, Singh G. A technique to prevent overfilling of viewing chamber of intravenous infusion kit. Indian J Anaesth 2014;58:780-1
|How to cite this URL:|
Kakani L, Sharma SM, Mehta RC, Singh G. A technique to prevent overfilling of viewing chamber of intravenous infusion kit. Indian J Anaesth [serial online] 2014 [cited 2020 Jan 26];58:780-1. Available from: http://www.ijaweb.org/text.asp?2014/58/6/780/147185
In certain patients, peripheral venous access is possible only in one limb, and the blood pressure (BP) cuff can only be placed on this limb because the other limbs are being operated upon or are splinted. Inflation of the BP cuff on this limb leads to back flow of fluid/blood through the transfusion tubing leading to complete filling of the viewing chamber of the infusion kit, thereby limiting its utility. One method to prevent this is applying a pressure bag on the intravenous fluid bag. Another method is to pass part of the infusion set tubing under the BP cuff.  Lundberg et al. placed a modified squeeze-clamp onto a portion of the intravenous tubing and passed this between the Velcro layers of the BP cuff.  Inflation of the cuff caused occlusion of the tubing between the clamp and the Velcro layers. In a modification of the above method, a stylet is given the shape of a coil by passing it around the handle of a laryngoscope and the intravenous tubing is passed between the turns of this coil. This coil is then passed between the Velcro of the BP cuff.  Kondo et al. inserted the intravenous tubing between the halves of a spectacle case which was wrapped in a smaller pressure cuff that was connected to the patient's pressure cuff by a T connector. 
We describe a technique that prevents overfilling of the viewing chamber. It requires an air free collapsible fluid bag and will not work with bottles. After filling the viewing chamber with sufficient fluid, the fluid bag is hung on the stand in an upside down manner using towel clip [Figure 1]. The viewing chamber is pasted onto the side of the fluid bag using micropore tape (3M TM ). Upon starting the infusion, when the BP cuff inflates, fluid in the infusion tubing moves up the tube to fill the viewing chamber. Air in the viewing chamber gets pushed to the top of the inverted fluid bag. With cuff deflation, the infusion starts again. The air that was pushed into the bag moves back into the viewing chamber. The air-fluid interface in the viewing chamber and its visual utility is maintained. The entire fluid can be transfused without obscuring the vision in the viewing chamber due to fluid filling caused by repetitive inflation of the BP cuff. The viewing chamber need not be emptied repetitively to maintain vision. Dextrose containing fluids should be avoided with this technique. Mixing of blood with dextrose causes clumping and possible clot formation every time blood ascends up the tubing.
|Figure 1: Arrows showing method of hanging collapsible fluid bag and fluid being transfused|
Click here to view
The phenomenon is explained by Bernoulli's principle.  For an inviscid (fluid that has no viscosity) flow, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or the fluid's potential energy. This is comparable to a siphon that works because gravity pulling down on the taller column of liquid causes reduced pressure at the top of a siphon. Application of a simple principle of physics helps in maintaining the utility of the viewing chamber of the infusion kit.
| References|| |
Brin EN, Lewis TC, Brin JA. A simple method for reducing backup of blood into intravenous lines caused by inflation of a blood pressure cuff. Anesth Analg 1990;71:569.
Lundberg J, Lee J, Toung TJ. Blood pressure measurements and intravenous infusions: A simple clamp to prevent retrograde blood flow. Anesthesiology 1996;85:943.
Maekawa N, Mikawa K, Nishina K, Kiyonari Y, Obara H. A simple device for preventing retrograde flow of blood into intravenous lines caused by blood pressure measurements. Anesth Analg 1996;83:665.
Kondo M, Nomura R, Enoki T. A simple device to prevent back flow of blood into the intravenous line. Anesthesiology 1998;88:1693.
Batchelor GK. An Introduction to Fluid Dynamics. Cambridge: Cambridge University Press; 1967. p. 156-64.