BiPAP is a non-invasive ventilatory assist machine. Non-invasive ventilation (NIV) machines are those that can
help breathing without requiring a tube inserted into the persons airway. By pushing air into the lungs through a
mask worn over the nose, NIV assists breathing. This technology was developed in the 1980's to help people with sleep
apnea, a condition where the airway collapses during sleep causing the person to stop breathing repeatedly. By
pushing air in, the machine keeps the airway "inflated" so it won't collapse. This is CPAP, Continuous Positive
In the 1990's computer technology added a new dimension to NIV. Now the machine could push air in until a preset
pressure was reached, then reduce the pressure to allow the person to exhale easily. Repeating this cycle made
breathing more comfortable and suitable for people with neuromuscular diseases who could not exhale against the
higher pressure. This type of machine was sold by Respironics using the brand name BiPAP (Bi-level Positive Airway
Pressure). Like the brand name "Kleenex", BiPAP has become the common name for all such products.
BiPAP is a ventilatory assist machine, but it is not a full featured traditional ventilator. A ventilator can do
everything BiPAP does but a BiPAP can't do all the things a ventilator can. There are several critical distinctions
between BiPAP and a traditional ventilator:
- BiPAP is "non-invasive", requiring only a mask that can put on or taken off as needed. The acronym "NIV"
(Non-Invasive Ventilation) is used to differentiate traditional, trached ventilation from CPAP and BiPAP. A
traditional ventilator is "invasive" meaning it requires that a tube be put down your throat or through your
neck (tracheotomy) into the lungs. The tube remains in place as long as the patient needs to use the
ventilator even if they reach a point where they can be off the ventilator for hours at a time. A growing
trend is to use a hybrid ventilator such as the Trilogy which can be set for bilevel ventilation with a mask
or mouth held tube, giving the non-invasive benefits of BiPAP, or for use with a trach and vent. This option
makes the transition to trach ventilation easier if it becomes necessary. Getting insurance coverage for an
expensive vent to be used for BiPAP is likely to be difficult however.
- BiPAP is not generally considered "Life Support Equipment." A ventilator can be set to completely take
over breathing, BiPAP can only assist the breathing.
- A ventilator is generally set to deliver air according to volume. It pumps air in until a certain volume
has been reached, then releases it. BiPAP delivers air according to pressure, stopping when it senses
resistance that tells it that the pre-set amount of pressure has been met. That is a technical
difference that probably means very little in how it feels to be on a ventilator versus BiPAP. It may however
affect how well lung function is maintained. A volume based air delivery will continue to inflate lungs fully
and help prevent atelectasis (loss of the ability of the little air sacs at the furthest reaches of the lungs
to expand) and pneumonia. A pressure based delivery system will sense resistance and not try to push air into
stiff or clogged air sacs and therefore won't be as helpful in keeping them working.
- BiPAP cannot support breathing adequately as ALS progresses. When breathing becomes very shallow, BiPAP
doesn't have the sensors to recognize this nor the built in ability to compensate by increasing pressure. A
ventilator will sense this and alarm. A ventilator can deliver higher pressures than BiPAP is designed to
- Because BiPAP only pushes air in until the set pressure is reached, it won't deliver enough air when the
lungs are filling up with congestion. It will reach the set pressure faster and switch to exhale, leaving you
dangerously under-oxygenated, struggling for more air, and exhausting your breathing muscles. A trip to the
ER and facing the question of whether to go on a full vent and trach is next.
- Ventilator patients can be fitted with trach tubes that allow them to eat and even to speak, but
occasionally this is not possible for ALS patients. Because it does not require a trach, BiPAP does not
interfere with any speech or swallowing they can still do.
- ALS patients often reach the point of not being able to cough effectively. With a ventilator and trach,
secretions can be removed by passing a suction tube through the trach to remove secretions. If suctioning is
needed by patients using BiPAP, the tube has to be passed through the nose or mouth.
- The presence of the trach increases the risk of lung infections because it bypasses some of the normal
protective barriers. Use of BiPAP also creates some increased risk for lung infections and sinus
One final comparison between Bilevel respiratory support is the warning that a ventilated person requires 24/7
care. That is true and yet misleading.
- How many people who are on bilevel ventilation during the day, whether parttime or full time, are safe at
home alone anyway? Arm weakness is usually a big part of the picture by this point so putting on or adjusting
the head gear requires assistance as does using a cough assist. Power outages, equipment malfuntion,
toileting, choking, mosquito attacks, fire, etc. all require assistance 24/7 regardless of the type of
respiratory equipment needed.
- The care required can be provided by anyone given ten minutes of instruction on how to suction and the
opportunity to practice doing so. A little info on how to troubleshoot a beeping vent and using an ambu bag
and they are all set. No licensed nursing care needed.
- The caregiver doesn't need to be in the room or even in the house. As long as they are close enough to
get back in a minute or two and a reliable method for the PALS to summon them has been set up they can have
the freedom to spend the afternoon outside or at a neighbors watching football.