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Introduction:

The Respironics BIPAP is a low pressure, electrically driven, flow triggered, lightweight non-continuous ventilator that provides pressure support ventilation via a nasal mask. The BIPAP name is derived from Bi-level Positive Airway Pressure. The BIPAP system is intended to augment patient ventilation by supplying pressurized air through a mask. Assistance is provided by the administration of two levels of positive pressure. During exhalation, pressure is variably positive or near ambient. The inspiratory level is variably positive, and is always higher than the expiratory pressure. Although the unit is intended to be used with an FI02 of 21%, supplemental oxygen can be bled directly into the patient mask. Generally, oxygen flow rates of 1-2 lpm are sufficient to maintain an adequate oxygen saturation.

BIPAP VENTILATORY SUPPORT SYSTEM

INTRODUCTION:

BiPAP is a low pressure, electrically driven, flow triggered, lightweight non-continuous ventilator that provides pressure support ventilation via a nasal mask. The BiPAP name is derived from Bi-level Positive Airway Pressure. The BIPAP system is intended to augment patient ventilation by supplying pressurized air through a mask. Assistance is provided by the administration of two levels of positive pressure. During exhalation, pressure is variably positive or near ambient. The inspiratory level is variably positive, and is always higher than the expiratory pressure. Although the unit is intended to be used with an Fi02 of 21%, supplemental oxygen can be bled directly into the patient mask. Generally, oxygen flow rates of 1-2 lpm are sufficient to maintain an adequate oxygen saturation.

 

                   

 

 

 

 

 

 

 

 

 

A flow transducer in series with the patient circuit as well as the patient outlet permits the BIPAP system to respond nearly instantaneously to the patient's inspiratory and expiratory efforts. Data from the flow transducer is continually processed and adjustments are automatically made to trigger thresholds. These corrections provide high sensitivity to inspiratory efforts and permit rapid adjustments for changing leaks within the system (mask leaks).

Nasal intermittent positive pressure ventilation has been used successfully with patients suffering from chronic alveolar hypoventilation syndrome secondary to obstructive sleep apnea, progressive neuromuscular respiratory insufficiency, and restrictive chest wall or parenchymal disease.

 

MODES of OPERATION:

SPONTANEOUS (S) MODE

The unit cycles between the inspiratory (IPAP) and expiratory (EPAP) levels in response to patient triggering.

Function Selector Knob: Spontaneous (S) Active Controls: IPAP, EPAP

SPONTANEOUS/TIMED (S/T) MODE

The unit cycles between the IPAP and EPAP levels in response to patient triggering. If the patient fails to initiate a breath, the unit will cycle into IPAP based on a preset interval determined by the synchronized rate (BPM) control. Function Selector Knob: Spontaneous/Timed (S/T) IPAP, EPAP, BPM

The unit cycles between the IPAP and EPAP levels based solely on the timing interval as determined by the rate (BPM) and the inspiratory time (%IPAP) controls. The patient may superimpose spontaneous breaths at any point over the IPAP and EPAP levels.

Function Selector Knob: Timed (T)

Active Controls: IPAP, EPAP, BPM, %IPAP

Active Controls:

TIMED (T) MODE

 

CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP)

With the function selector set in the IPAP position, the desired CPAP level is obtained by adjusting the IPAP control.

Function Selector Knob: IPAP

Active Controls: IPAP

DESCRIPTION of CONTROLS:

FUNCTION SELECTOR KNOB: Determines which function or mode is active.

These positions are used when calibrating the external recorder.

Inspiratory Positive Airway Pressure: The pressure level that is maintained during the inspiratory phase of the S, S/T, or T modes.

Expiratory Positive Airway Pressure: The pressure level that is maintained during the expiratory phase of the S, S/T, or T modes.

  • Prior to initiation of the therapy, check the physician's written order. To be complete, the order should include the mode, IPAP and EPAP settings, Fi02, and time considerations.
  • Read the patient's chart carefully for information about his/her disease state.
  • If the patient has not received the therapy before, explain the process and equipment to him/her. Patient understanding and acceptance is important. You may want to let the patient hold the mask over their nose as a trial prior to using the head strap.

Breaths per minute control, the range is 4-30 bpm.

This control is active when the T mode only is selected. It determines the fraction of the respiratory phase spent in IPAP.

PROCEDURE:

NOTE:

Identify whether the patient ordered for BiPAP meets selection criteria noted in Table 1.

PATIENT SELECTION CRITERIA FOR THE APPLICATION OF NON-INVASIVE POSITIVE PRESSURE VENTILATION IN ACUTE VENTILATORY FAILURE

 

Table 1
Subjects must:
  • Be cooperative and able to synchronize with the ventilator
  • Be able to achieve a proper mask fit
  • Have intact cough reflex and swallowing function
  • Be hemodynamically stable
  • Not have multi-organ dysfunction
  • Not have upper GI bleeding
  • Not have excessive secretions
  • Not have facial trauma

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The IPAP and EPAP controls are electrically coupled. The unit will not deliver a higher EPAP than IPAP level. If the EPAP is set higher than the IPAP, the unit will lock into the IPAP setting and the IPAP light will remain lit.

  • Carefully fit the nasal mask. Select the smallest mask to comfortably fit the patient. Masks are available in seven sizes (Petite-Large). The mask should fit from the bridge of the nose to just below the nares. Be careful that the mask rests above the upper lip.
  • Once the correct mask has been selected, connect the WHISPER SWIVEL to the mask and attach one end of the large bore corrugated tubing to the WHISPER SWIVEL. The WHISPER SWIVEL is designed to exhaust C02 from the patient circuit. It is imperative that a WHISPER SWIVEL be in-line and it's slots unobstructed for the safe operation of the BIPAP system.
  • Attach the other end of the corrugated tubing to the outlet port of the BIPAP unit. If supplemental oxygen is necessary, attach the oxygen connecting tubing to the mask prior to application to the patient. Fit the mask loosely over the patient's nose and attach a foam spacer to the mask.
  • Plug the electrical cord into an electrical outlet that is fed by the hospital's emergency power system. Turn the unit on.
  • Apply the mask that you have selected to the patient's face and attach the head straps. Tighten the straps until all of the significant leaks are eliminated. Avoid over tightening as this will cause patient discomfort. Verify the set pressures with a manometer.

INITIAL SETTINGS: (suggested)

  1. IPAP: 8-10 cm H20
  2. EPAP: 3 - 5 cm H20
  3. Fi02: Match current administration. Follow oximeter.
  4. BPM: Match current rate +/- 2
  5. Mode: As clinically indicated. A description of the various modes can be found in "Modes of Operation" section of this policy.

Adjustment of BIPAP system should be made per ABG's and patient comfort. When using the Spontaneous (S) mode, (ex. OSA patients), ABG Is should be obtained at the end of the nocturnal ventilatory period. When using the Timed (T) or Spontaneous/Timed (S/T) mode, (ex. neuromuscular patients), ABG's must be obtained 2-3 hours after the initiation of the therapy as well as after subsequent ventilator changes.

IPAP Increase the IPAP in increments of 2 cm H20

Increasing the "pressure boost" may; increase alveolar ventilation, relieve the sense of dyspnea, and the use of accessory muscles.

EPAP Increase the EPAP in increments of 2 cm H20

Increasing the Functional Residual Capacity should improve the patient's oxygenation. (Remember that the EPAP level cannot exceed the IPAP level).

Supplemental oxygen can be titrated into the nasal mask to obtain an acceptable PaO2 and PaCO2

 

CONTRAINDICATIONS:

  • Preexisting pneumothorax or pneumomediastinum.
  • Hypotension due to or associated with intravascular volume depletion.
  • Pre-existing bullous lung disease may represent a contraindication.
  • Pneumocephalus has been reported in patients using nasal CPAP5.
  • Facial/skull fractures, as well as patients with elevated ICP.
  • Post operative patients who have recently under gone abdominal surgery may not be appropriate candidates for BiPAP or nasal CPAP.

OPERATIONAL CONSIDERATIONS:

  • Experience has shown that the best results occur when trial periods of 30 minutes or longer, are attempted on two or three occasions prior to their first overnight trial. Patients who are gradually acclimated to this device in the above mentioned fashion do- considerably better than those who's initial exposure/trial is initiated at bedtime.
  • Patients should refrain from eating 1-2 hours prior to the application of the BIPAP system.
  • Heat moisture exchangers (HME) should not be used with the BIPAP system. Testing has shown that the HME may interfere with the ability of the BIPAP system to maintain the prescribed pressures.
  • Supplemental humidification, if necessary, can be provided by a passover humidifier. Experience has shown that with adult patients, forgoing the addition of a humidifier for 2-3 days in most instances negates the need for such a device. The patient's mucociliary blanket appears to adapt to the new conditions. Pediatric patients however have all required humidification.
  • Oximetry should be performed prior to the initiation of this therapy as well as when the BIPAP system is in place. The oximetry will not only aid in the titration of the oxygen but will serve as tool to monitor the effectiveness of this therapy.
  • Although no reports of gastric distension or aspiration have been reported, the most common complication has been abrasion of the bridge of the nose. Application of wound-care dressing appears to eliminate this problem.

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