the efficacy of a new mathematical formula to predict continuous positive air pressure with an oronasal mask interface.

Conditions: Obstructive Sleep Apnea (OSA)

Summary: subjects will all have a two week baseline period in which they will use a nasal mask using an air view cpap machine (which records all data). after the two week period all will switch to a full face mask with half using the same cpap pressure and half with a new a cpap pressure derived from our formula for the final two weeks.

the goal of this study is to test the efficacy of an algorithm the investigators previously created to adjust continuous positive airway pressure (cpap) when a mask interface is switched from a nasal to a full face. subjects will currently have a moderate to severe apnea-hypopnea index (ahi - the apnea-hypopnea index or apnoea-hypopnoea index (ahi) is an index used to indicate the severity of sleep apnea. it is represented by the number of apnea and hypopnea events per hour of sleep). (above 15) * scoring of apneas score a respiratory event as an apnea when both of the following criteria are met: n1, n2, n3, n4 1. there is a drop in the peak signal excursion by ≥90% of pre-event baseline using an oronasal thermal sensor (diagnostic study), pap device flow (titration study) or an alternative apnea sensor (diagnostic study) 2. the duration of the ≥90% drop in sensor signal is ≥ 10 seconds. score an apnea as obstructive if it meets apnea criteria and is associated with absent inspiratory effort throughout the entire period of absent airflow. score an apnea as central if it meets apnea criteria and is associated with absent inspiratory effort throughout the entire period of absent airflow. score an apnea as mixed if it meets apnea criteria and is associated with absent inspiratory effort in the initial portion of the event, followed by resumption of inspiratory effort in the second portion of the event. n4 note 1 - identification of an apnea does not require a minimum desaturation criterion. note 2 - if a portion of a respiratory event that would otherwise meet criteria for a hypopnea meets criteria for apnea, the entire event should be scored an apnea. note 3 - if the apnea or hypopnea event begins or ends during an epoch that is scored as sleep, then the corresponding respiratory event can be scored and included in the computation of the apnea hypopnea index (ahi). this situation usually occurs when an individual; has a high ahi with events occurring so frequently that sleep is severely disrupted and epochs may end up being scored as wake even though \<15 seconds of sleep is present during the epoch containing that portion of the respiratory event. however if the apnea or hypopnea occurs entirely during an epoch scored as wake, it should not be scored or counted towards the apnea hypopnea index because of the difficultly of defining a denominator in this situation. if these occurrences are a prominent feature of the polysomnogram and/or interfere with sleep onset, their presence should be mentioned in the narrative summary if the study. note 4 - for alternative apnea sensors see tech specifications for adults. there is not sufficient evidence to support a specific durations of the central and obstructive components of a mixed apnea thus specific durations of these components are not recommended. * aasm 2015 protocol scoring of hypopneas score a respiratory event as a hypopnea if all of the following criteria are met. n1, n2, n3. 1. the peak signal excursions drop by ≥30% of pre-event baseline using nasal pressure (diagnostic study), pap device flow (titration study), or an alternative hypopnea sensor (diagnostic study). 2. the duration of the ≥30% drop in signal excursion is ≥10 seconds. 3. there is a ≥3% oxygen desaturation from pre-event baseline or the event is associated with an arousal. subjects once consented and entered into the study, will all have a two week baseline period in which they will use a nasal mask using an airview cpap machine (which records all data). after the two week period all will switch to a full face mask with half using the same cpap pressure and half with a new cpap pressure derived from our formula for the final two weeks. those placed in the randomized into a new pressure will have an experimental procedure of getting a new pressure. the investigators expect the ahi of the controls to increase. our two new formulas are referred to as opred (oronasal) (full face mask) and npred (nasal) (non-full face mask). npred=(0.017 ahi)-(0.092 lsao2)+(0.225 nc)+5.534 opred=(0.03 ahi)-(0.130 lsao2)+19.732 nc=neck circumference, ahi= baseline ahi, lsao2= lowest blood oxygen saturation from the baseline polysomnogram. these models were developed using multiple linear regressing modeling. the study is self-funded because it has no funding. subjects will not be compensated

Eligibility criteria:
inclusion criteria: * ahi above 15. * willing to switch to full face mask post titration. * not currently on a weight loss plan and no intention of beginning a weight loss regimen during the duration of the study exclusion criteria: * ahi below 15. * not willing to switch to full face mask post titration. * currently on a weight loss plan and / or intention of beginning a weight loss regimen during the duration of the study.