Gas removal in an intravenous fluid delivery system
View Patent ↗An active gas removal system is provided to remove air or gas bubbles from an intravenous fluid prior to infusion into the patient. The system detects the level of liquid in a drip chamber and occludes a downstream valve to the patient, thereby increasing pressure in the drip chamber sufficient to open a vent valve and release gas therein.
1. A system for the removal of gas bubbles from an intravenous liquid flowing in intravenous tubing, the system comprising:
a drip chamber having an inlet connected to intravenous tubing from an intravenous source and an outlet connected to intravenous tubing to a patient, the inlet disposed at a higher level than the outlet, wherein the drip chamber retains gas at an upper portion thereof;
a liquid level sensor operative to sense the level of liquid in the drip chamber;
a vent valve at an upper portion of the drip chamber operative to open upon a predetermined increase of gas pressure within the drip chamber;
a continuously operative pump upstream of the drip chamber operative to continuously pump the intravenous liquid from the intravenous source to the patient;
an occlusion valve downstream of the drip chamber operative to stop liquid flow in the intravenous tubing from the drip chamber to the patient; and
a controller in communication with the liquid level sensor and the downstream occlusion valve and operative to close the downstream occlusion valve upon detection of a specified liquid level in the drip chamber detected by the liquid level sensor, whereby continued pumping operation of the upstream continuously operative pump while the downstream occlusion valve is closed causes an increase of pressure in the drip chamber sufficient to open the vent valve and release gas in the drip chamber.
2. The system of claim 1 , wherein the vent valve comprises a check valve.
3. The system of claim 1 , wherein the vent valve comprises an umbrella check valve.
4. The system of claim 1 , further comprising a hydrophobic filter disposed before the vent valve to prevent the intravenous fluid passing through the vent valve.
5. The system of claim 1 , wherein the controller is further operative to open the occlusion valve.
6. The system of claim 1 , wherein the liquid level sensor comprises a variable level sensor to detect a high liquid level and a low liquid level in the drip chamber and the controller is operative to provide an indication of detection of a predetermined high liquid level.
7. The system of claim 1 , further comprising a further liquid level sensor operative to detect a high liquid level in the drip chamber and the controller is operative to provide an indication of detection of a predetermined high liquid level.
8. In an intravenous system including a drip chamber having an inlet connected to intravenous tubing from an intravenous source and an outlet connected to intravenous patient tubing, wherein the drip chamber retains gas at an upper portion thereof, and a continuously operative pump upstream of the drip chamber operative to continuously pump intravenous liquid from the intravenous source to the patient, a method for removal of gas in the drip chamber, the method comprising:
providing a liquid level sensor for sensing liquid level in the drip chamber;
providing a vent valve at an upper portion of the drip chamber;
providing a valve downstream of the drip chamber;
closing the downstream valve in response to a predetermined liquid level sensed by the sensor to cause, by continued operation of the continuously operation pump, an increase in pressure in the drip chamber sufficient to open the vent valve and release gas from the drip chamber; and
after release of gas from the drip chamber, opening the downstream valve.
9. The method of claim 8 , further comprising:
sensing a low liquid level and a high liquid level in the drip chamber; and
providing an indication of detection of a predetermined high liquid level.
10. A method for removal of gas from an intravenous fluid line in an intravenous fluid infusion system, comprising:
providing an intravenous infusion system comprising an intravenous fluid line, a continuously operative pump to deliver intravenous fluid to a patient through the intravenous fluid line, and a drip chamber downstream of the continuously operative pump, a vent valve disposed at an upper portion of the drip chamber;
continuously pumping the intravenous fluid to a patient through the fluid line;
collecting intravenous fluid in a bottom portion of the drip chamber prior to infusion to the patient and retaining gas in an upper portion of the drip chamber;
sensing a liquid level in the drip chamber;
occluding the fluid line at a location downstream of the drip chamber in response to a predetermined level in the drip chamber sensed by the sensor sufficient to cause an increase in pressure in the drip chamber by continued pumping operation of the continuously operative pump to open the vent valve and release gas from the drip chamber; and
after release of gas from the drip chamber, opening the fluid line to allow fluid flow to resume through the fluid line.
11. The method of claim 10 , further comprising sensing a low liquid level and a high liquid level in the drip chamber; and
providing an indication of detection of a predetermined high liquid level.