Initiation Of Pacing

The Spirit output starts at 300. Starting with an amplitude of 300, please follow the instructions below for initiation of pacing or re-establishing thresholds.

These steps must be performed in the same order as listed:

Establishing Threshold

Regardless of patient diagnosis, determination of each hemidiaphragm threshold is required prior to the start of effective bilateral diaphragm pacing. Threshold is the lowest amplitude setting that causes muscular contraction. The procedure to determine threshold amplitudes is as follows:

  1. Insert 4 new batteries into the Spirit. Use only alkaline batteries. Do not use rechargeable batteries.
  2. Turn off both sides of the Spirit by pressing the power ON/OFF buttons on the keypad.
  3. Connect the left and right antennas carefully into the corresponding sockets marked PATIENT LEFT and PATIENT RIGHT.
  4. Turn on the left side by pressing the left power ON/OFF key.
  5. Adjust the amplitude on the left side to 300 by pressing the UP arrow key.
  6. Ensure that the left antenna is properly positioned over the receiver site, firmly affixed with adhesive tape or other snug dressing.
  7. If required, preoxygenate patient as needed then discontinue alternate means of ventilation.
  8. To determine the threshold, starting at 300, slowly increase the amplitude by pressing the left UP arrow key until the smallest diaphragm contraction is observed while the three-wave icon on the display is visible.
  • Note:  Threshold is the lowest stimulus amplitude to produce the smallest contraction of the diaphragm.
  • Note: Stimulation occurs when the three-wave icon over the antenna icon appears (inspiratory period). When the three-wave icon disappears (expiratory period), there is no stimulation.
  1. Once the threshold has been determined for the left side, thoroughly ventilate the patient (as needed).
  2. Turn off the left side of the Spirit and repeat the above procedure starting at step 4 to determine threshold for the right side.
  • Please refer to the Instruction Manual provided with each system for complete instructions on Postoperative Care and Initiation of Pacing

Adjusting Amplitude

  1. After determining the threshold on the left and right sides, the optimal amplitudes need to be determined.
  • Note: In general, the higher the amplitude, the larger the diaphragm contraction.
  1. Turn on both sides of the Spirit. Starting at threshold amplitudes, gradually increase the amplitudes on the left and right side by pressing the UP arrow keys until the patient achieves optimal tidal volume and diaphragm contraction without feeling discomfort.
  • Note: If the patient feels discomfort, lower the amplitudes while still maintaining optimal diaphragm contraction and tidal volume. If this cannot be achieved, call Avery Customer Service.
  • Note: Tidal volumes on the right are often larger than the volumes on the left because of size difference between the two lungs.

Adjusting Breathing Rate

The breathing rate is set to provide the minute volume required by the patient:

  • Minute Volume = Breathing Rate x Tidal Volume

The breathing rate is factory set at 12 bpm and should be adjusted to provide adequate ventilation dependent upon the Tidal Volume obtained and the Minute Volume requirement of the patient.

Initiation Of Pacing Spirit Video

For the Spirit Transmitter, an illustration of initiation of pacing is featured in the video below.

Play Video

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Instruction Manuals

Every Avery transmitter  includes an Instructional Manual. If you need to replace yours or need an additional copy, please call us or fill out our Customer Service Form and we will gladly mail or email you another copy. 

Avery Technicians are available by telephone to assist with troubleshooting and provide technical support during normal business hours (8 AM to 4 PM Eastern Time, Monday through Friday). At other times, please leave a message and someone will return your call at the earliest opportunity. Requests of a non-urgent nature can be sent thought our Contact Us Form below.

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