Drip Alert



The Drip Alert™ device is intended to be used as supplementary intravenous drip monitoring system for monitoring the drip rate of fluids being administered, using an intravenous administration set. If the drip rate of fluid passing through a drip-chamber falls outside the acceptable rate of variation, an audible alarm will sound. The device is for use in either hospital or home healthcare settings. Drip Alert™ is a passive device that does not control the drip rate of fluids passing through a drip chamber; rather it acts solely as a monitoring tool. The device uses a microprocessor, a standard infrared drop sensor unit, and a power source in the housing that is capable of being attached to the drip-chamber of an intravenous administration set. The drop-sensing unit has one infrared emitter and two infrared receivers. The infrared emitter faces a low voltage operation amplifier. Drops falling from the top of the drip-chamber pass between the infrared emitter and the infrared receivers. The unit senses the drips and sends signals to a microprocessor that is powered by a battery power source. The drop sensing unit, the operation amplifier, the power source and the microprocessor are encased in the housing. The housing is made of flexible plastic and has a U shaped arm capable of attaching to both macro and micro drip-chambers of intravenous administration sets and has a smaller arm for attaching to the IV tubing so that the device is securely attached to the administration set. Two (2) AAA alkaline batteries power the device. The device has an on/off switch. When the switch is in the “on” position, battery power is provided to the microprocessor. The microprocessor contains a 32768Hz crystal clock that achieves a very high precision clock ratio. All electronic components within the device are low voltage. The drop sensing unit detects and amplifies a drop of fluid falling through a drop-chamber of the intravenous administration set and creates a pulse which is amplified and communicated to the microprocessor when a drip is detected. The microprocessor monitors the amplified pulses sent from the drip-sensing unit and performs a drip rate calculation (further defined below). Using an algorithm, (which determines a drip rate variation range and represents a tolerance ratio for the drip rate), a drip rate calculation is created. The device includes an audible signal used to indicate four (4) separate functionalities: When the device is initially turned on, when the device is calculating the initial drip rate, when deviation from an acceptable drip rate occurs and when the battery power is low. Different signals represent each of the different conditions so that the user readily recognizes them. The device has an additional switch between two different, pre-set drip variation ranges. The intended drip variation ranges are plus or minus 12.5% and plus or minus 18.75%. However, the microprocessor can be programmed to calculate any drip rate variation range. The microprocessor periodically turns the sensor unit off and on for a fixed period of time to minimize power consumption while maintaining accuracy of drip rate. Because discrete binary number does all calculation, the truncate/overflow error is minimized. The device is used by fitting the housing around the drip-chamber of a administration set such that the infrared emitter and two infrared receivers of the drop sensing unit face each other and inserting the administration set tubing just below the drip chamber into the tube holding member. When the device switch is in the “on” position, power is provided to the microprocessor and the drop sensing unit is capable of detecting drops falling from the top of the drip-chamber into the lower part of the drip-chamber. When the device is calibrated (during set up), the device sounds two audible signals. The drop-sensing unit counts nine individual drops producing a single audible signal after each drop one through eight and two audible signals after drop nine. The drop-sensing unit sends the amplified pulse information to the microprocessor, which calculates the actual flow rate as an average interval of eight drops. The eight-drop average interval equals (t). The microprocessor monitors drip rates that fall between .5 seconds and 12 seconds. The microprocessor determines whether (t) is between .5 seconds and 12 seconds by performing the calculation (.5 seconds<t<12 seconds). If (t) falls outside the drip rate range, the microprocessor will recalculate (t) until the drip rate falls within the drop rate range. If the microprocessor recalculates more than 3 times, a constant audible signal will sound and the IV administrator will need to reset the drip rate and the process will start over. If (t) is calculated to be within the acceptable drop rate range within one to three calculations during calibration, four (4) consecutive audible signals will sound, signaling that the drip rate falls within the acceptable drip rate range. If the drip rate falls within the acceptable drip rate range, the drop-sensing unit will continue to monitor the average drop interval (t). If no drop is counted for a 5 (t) intervals, the microprocessor will sound a constant audible signal, alerting the IV administrator to reset the drip rate and begin the monitoring process once again. When the drip rate continues to fall within the acceptable drip rate range, the microprocessor will determine whether the drip rate falls within an acceptable variation range by performing the calculation (t (1-x%)< t < t (1+x%)) with the integer x representing the percentage of acceptable variation in the rate. For example, if the acceptable percentage of variation is 12%, the formula will be (t(1-12%)< t < t (1+12%)). The microprocessor will continue to monitor the average drip interval (t). When the average drip interval (t) falls outside the acceptable variation range, the microprocessor will recalculate the drip count until either the drip rate falls within the tolerance range, or if more than three recalculations occur. If the microprocessor recalculates the drip rate three or less times and it falls within the acceptable variation rate, the drip-sensing unit will count eight drops and recalculate the average drip rate of the eight drops. The microprocessor also monitors the battery power source and will produce a constant audible sound if the battery power source is low. Download a PDF Drip Alert instruction manual here

The Drip Alert™ device is intended to be used as supplementary intravenous drip monitoring system for monitoring the drip rate of fluids being administered, using an intravenous administration set. If the drip rate of fluid passing through a drip-chamber falls outside the acceptable rate of variation, an audible alarm will sound. The device is for use in either hospital or home healthcare settings. Drip Alert™ is a passive device that does not control the drip rate of fluids passing through a drip chamber; rather it acts solely as a monitoring tool. The device uses a microprocessor, a standard infrared drop sensor unit, and a power source in the housing that is capable of being attached to the drip-chamber of an intravenous administration set. The drop-sensing unit has one infrared emitter and two infrared receivers. The infrared emitter faces a low voltage operation amplifier. Drops falling from the top of the drip-chamber pass between the infrared emitter and the infrared receivers. The unit senses the drips and sends signals to a microprocessor that is powered by a battery power source. The drop sensing unit, the operation amplifier, the power source and the microprocessor are encased in the housing.

The housing is made of flexible plastic and has a U shaped arm capable of attaching to both macro and micro drip-chambers of intravenous administration sets and has a smaller arm for attaching to the IV tubing so that the device is securely attached to the administration set. Two (2) AAA alkaline batteries power the device. The device has an on/off switch. When the switch is in the “on” position, battery power is provided to the microprocessor. The microprocessor contains a 32768Hz crystal clock that achieves a very high precision clock ratio. All electronic components within the device are low voltage. The drop sensing unit detects and amplifies a drop of fluid falling through a drop-chamber of the intravenous administration set and creates a pulse which is amplified and communicated to the microprocessor when a drip is detected. The microprocessor monitors the amplified pulses sent from the drip-sensing unit and performs a drip rate calculation (further defined below).

Using an algorithm, (which determines a drip rate variation range and represents a tolerance ratio for the drip rate), a drip rate calculation is created.

The device includes an audible signal used to indicate four (4) separate functionalities: When the device is initially turned on, when the device is calculating the initial drip rate, when deviation from an acceptable drip rate occurs and when the battery power is low. Different signals represent each of the different conditions so that the user readily recognizes them. The device has an additional switch between two different, pre-set drip variation ranges. The intended drip variation ranges are plus or minus 12.5% and plus or minus 18.75%. However, the microprocessor can be programmed to calculate any drip rate variation range. The microprocessor periodically turns the sensor unit off and on for a fixed period of time to minimize power consumption while maintaining accuracy of drip rate. Because discrete binary number does all calculation, the truncate/overflow error is minimized.

The device is used by fitting the housing around the drip-chamber of a administration set such that the infrared emitter and two infrared receivers of the drop sensing unit face each other and inserting the administration set tubing just below the drip chamber into the tube holding member. When the device switch is in the “on” position, power is provided to the microprocessor and the drop sensing unit is capable of detecting drops falling from the top of the drip-chamber into the lower part of the drip-chamber.

When the device is calibrated (during set up), the device sounds two audible signals. The drop-sensing unit counts nine individual drops producing a single audible signal after each drop one through eight and two audible signals after drop nine. The drop-sensing unit sends the amplified pulse information to the microprocessor, which calculates the actual flow rate as an average interval of eight drops. The eight-drop average interval equals (t). The microprocessor monitors drip rates that fall between .5 seconds and 12 seconds. The microprocessor determines whether (t) is between .5 seconds and 12 seconds by performing the calculation (.5 seconds<t<12 seconds). If (t) falls outside the drip rate range, the microprocessor will recalculate (t) until the drip rate falls within the drop rate range. If the microprocessor recalculates more than 3 times, a constant audible signal will sound and the IV administrator will need to reset the drip rate and the process will start over. If (t) is calculated to be within the acceptable drop rate range within one to three calculations during calibration, four (4) consecutive audible signals will sound, signaling that the drip rate falls within the acceptable drip rate range. If the drip rate falls within the acceptable drip rate range, the drop-sensing unit will continue to monitor the average drop interval (t). If no drop is counted for a 5 (t) intervals, the microprocessor will sound a constant audible signal, alerting the IV administrator to reset the drip rate and begin the monitoring process once again. When the drip rate continues to fall within the acceptable drip rate range, the microprocessor will determine whether the drip rate falls within an acceptable variation range by performing the calculation (t (1-x%)< t < t (1+x%)) with the integer x representing the percentage of acceptable variation in the rate. For example, if the acceptable percentage of variation is 12%, the formula will be (t(1-12%)< t < t (1+12%)). The microprocessor will continue to monitor the average drip interval (t). When the average drip interval (t) falls outside the acceptable variation range, the microprocessor will recalculate the drip count until either the drip rate falls within the tolerance range, or if more than three recalculations occur. If the microprocessor recalculates the drip rate three or less times and it falls within the acceptable variation rate, the drip-sensing unit will count eight drops and recalculate the average drip rate of the eight drops. The microprocessor also monitors the battery power source and will produce a constant audible sound if the battery power source is low.

Download a PDF Drip Alert instruction manual here