LiveO2 does not use Pos­i­tive Pres­sure because: 

1. Pos­i­tive pres­sure would inhib­it gas exchange in the lungs and reduce waste gas removal
2. Pos­i­tive pres­sure would reduce the strength­en­ing effect LiveO2 users achieve with extra air flow resistance
3. Pos­i­tive pres­sure would reduce the exer­tion effect that enables LiveO2 to pro­duce ben­e­fits in hand­i­capped users
4. Pos­i­tive pres­sure would like­ly cause LiveO2 to be clas­si­fied as a breath­ing assis­tance device

Breathing Mechanics

A sim­ple way to look at it is to look in the mir­ror.  Why did nature make your nos­trils small­er than your mouth?  It’s sim­ple.  Your nos­trils are small­er because air­flow resis­tance is an impor­tant part of breath­ing.  That’s why it’s nat­ur­al to breathe through your nose instead of your mouth. Res­pi­ra­tion is a cycle:

1. Rest between breaths with lungs empty
2. Inhale starts when CO2 dri­ves blood acidic
3. Inhala­tion vac­u­um pulls the CO2 & waste gasses out of the blood through the alve­o­lar membrane
4. Exhale pres­sure push­es oxy­gen across the alve­o­lar mem­brane into the blood
5. We rest with lungs emp­ty until we need anoth­er breath

Even though we don’t think about it, bod­ies nat­u­ral­ly reg­u­late air­flow resis­tance to opti­mize gas trans­fer. We use sev­er­al reflexes: 

• Inhale force is dri­ven by the urgency to reduce car­bon dioxide
• Exhale force and or blow through our lips is dri­ven by oxy­gen need
• How long we pause between breaths is dri­ven by how often we need to elim­i­nate CO2.

Breath­ing through the nose cre­ates air­flow for inhale and exhale like nature intend­ed.

The Role Airflow Resistance

We use air­flow resis­tance instinctively: 

• We inhale and exhale through the nose most of the time
• We blow out through the lips dur­ing exhale dur­ing exertion.

Both reflex­es increase air­flow resis­tance dur­ing breath but they have oth­er effects too.

During Inhale

Inhale resis­tance cre­ates two spe­cif­ic effects: 

1. 

   Vac­u­um pulls waste gas out of the blood. Waste gas is most­ly car­bon diox­ide, but includes oth­er gasses and tox­ins.  More resis­tance cre­ates more vac­u­um and helps our bod­ies elim­i­nate waste.
2. Inhala­tion resis­tance caus­es the chest to pull hard­er which strength­ens breath­ing mus­cles.  This resis­tance tends to strength­en a users from loss of strength in breath­ing mus­cles from long-term seden­tary lifestyles.
3. Inhala­tion resis­tance adds to the phys­i­cal work load of exercise.

During Exhale

Exhale force push­es oxy­gen into the blood to attach to hemo­glo­bin and to dis­solve in blood plas­ma.  Both are impor­tant but the increase in blood plas­ma oxy­gen con­cen­tra­tion is crit­i­cal. We instinc­tive­ly sup­ple­ment nor­mal exha­la­tion resis­tance by blow­ing through the lips to boost back pres­sure to push more oxy­gen into the blood. Exha­la­tion resis­tance adds to the phys­i­cal work load of exer­cise.

Bad Breath

Waste gasses cause breath odor. When you inhale the vac­u­um cre­at­ed in the alve­oli pulls these gasses out of the blood. Some­one that exer­cis­es is less like­ly to have bad breath. This is because stronger and more fre­quent vac­u­um cycle pulls out more waste gas.  Exer­cise cir­cu­lates much more blood through the lungs with high­er vac­u­um remov­ing more waste gas. Extra inhala­tion resis­tance dur­ing inhale helps the body pull more waste gasses out of the blood mak­ing breath­ing more effec­tive for waste gas elim­i­na­tion.

About LiveO2 Airflow Resistance

LiveO2 is a Neu­tral Pres­sure ™ breath­ing sys­tem because LiveO2 is intend­ed to work with nature. It took us quite a while to under­stand the how the mechan­ics of LiveO2 helped breath­ing. We were sur­prised to dis­cov­er that air­flow resis­tance was impor­tant to both oxy­gen absorp­tion and waste gas release. Air­flow resis­tance is a big part of breath­ing efficiency: 

1. Inhala­tion resis­tance improves waste gas removal
2. Inhala­tion resis­tance strength­ens inhale muscles
3. Inhala­tion resis­tance adds to the phys­i­cal dur­ing exercise
4. Exha­la­tion resis­tance increas­es the oxy­gen that attach­es to hemo­glo­bin in red blood cells
5. Exha­la­tion resis­tance increas­es the oxy­gen par­tial pres­sure in blood plasma
6. Exha­la­tion resis­tance increas­es phys­i­cal work dur­ing exercise.

Each one of these ele­ments is a rea­son NOT to inter­fere with nature and to encour­age air­flow resis­tance.’

Handicapped Users

When we start­ed work­ing with par­a­lyzed clients we real­ized that the phys­i­cal the work effect of breath­ing was impor­tant too. Peo­ple that lack con­trol of large mus­cles need the work effect of breath­ing against a resis­tance.  This turned out to be one rea­son LiveO2 worked so well for dis­abled users.

Our Basic Mask System

The LiveO2 Stan­dard Mask has a 3/4 inch diam­e­ter inflow port which enables most users to inhale with­out notice­able air­flow resis­tance at rest. Under load this small diam­e­ter port cre­ates a mild addi­tion­al inhala­tion resis­tance. Even­tu­al­ly we came to under­stand that this mild resis­tance con­tributed to the good results even though it added a mild dis­com­fort. Strong breathers did­n’t notice air­flow resis­tance and actu­al­ly like it.  Weak breathers dis­like it but need it because they are weak breathers and need to get stronger. Our dilem­ma was that air­flow resis­tance was both a ben­e­fit and a nui­sance.  What should we do? We dis­cov­ered  that any sort of pos­i­tive pres­sure in the breath­ing cir­cuit would reduce ben­e­fits of LiveO2. We even­tu­al­ly decid­ed to offer two mask sys­tems to enable our users to opti­mize comfort: 

• Stan­dard Mask Kit — Mild Air­flow Resistance
• Pre­mi­um Mask Kit — Near zero air­flow resistance
• Mask Kits Com­pared — Prac­ti­cal Dif­fer­ences between them

We also chose NOT to imple­ment any sort of pos­i­tive pres­sure because that fea­ture con­tra­dicts the instinc­tive sci­ence of effec­tive breath­ing.

Regulations of Pressurized Breathing Systems

Pos­i­tive pres­sure fea­tures sug­gest the device is intend­ed to assist a user with breath­ing. We also avoid­ed any sort of pos­i­tive pres­sure because the rules and reg­u­la­tions that gov­ern oxy­gen deliv­ery equip­ment define any device with pos­i­tive pres­sure as a med­ical device.  These devices have the appar­ent intent of pro­vid­ing breath­ing assis­tance to a user, like a CPAP machine. LiveO2 does not cross the line from pas­sive to an active breath­ing device on pur­pose.  LiveO2 is intend­ed mar­ket­ed an exer­cise device not a med­ical breath­ing appa­ra­tus.  It does not pro­vide pos­i­tive pres­sure to avoid usage restric­tions which would apply to a pres­sur­ized breath­ing appa­ra­tus. Addi­tion­al­ly there are spe­cif­ic label­ing require­ments for pres­sur­ized oxy­gen stor­age.   The reg­u­la­tions do not spec­i­fy how much pres­sure is required for a device to be con­sid­ered pres­sur­ized. Absent pres­sure, LiveO2 cus­tomers avoid more spe­cif­ic rules and reg­u­la­tions that apply to pres­sur­ized oxy­gen deliv­ery sys­tems.

See Also:

• About Adap­tive Contrast
• Stan­dard Mask Kit
• Pre­mi­um Mask Kit
• About Reser­voir Design