sleeptech

I very much agree Wiredgeorge. Doctors are paid very well to be responsible for your healthcare. They should explain everything fully to you at every stage. If your doctor is not explaining things to your satisfaction, make them. Or get another doctor. Being properly informed about your health makes a huge difference to the outcomes.

For masks we generally recommend simple dish washing detergent. I would be concerned that vinegar would have a negative effect on the rubber over time. Once a week is a good guideline for cleaning your mask, but it varies from person to person. Some people need to wash the mask pillow every day to achieve adequate seal, but most people get perfectly good result washing their mask once/week, and washing your mask less often will extend its life. Ultimately it's going on your face so it's up to you. But please DO wash it. You may be surprised, but there are plenty of people who just never wash their mask and the results are truly disturbing. Sometimes I just cannot believe what people put on their faces. Washing your face immediately before putting you mask on can also help with seal. An good alternative to washing with water and detergent is good old baby wipes. It is possible to get some which are unscented (I believe), and as long as they are alcohol free (which almost all are) they won't harm the mask. Avoid things sold specifically as CPAP cleaning wipes. They are a complete ripoff. Some CPAP suppliers sell them for sterilising your mask, but you don't need to sterilise it. It's not like you're sharing it with anyone. It only needs to be clean, not sterile. It is generally unnecessary to wash the tubing because the only thing that travels down it is plain ordinary air. You don't breathe back down it, all of your exhaled air is blown out of the exhalation port of the mask. If you have a humidifier and get condensation in your tube, do make sure you drain and dry your tube every morning, and the occasional wash may be worth while. Humidifier chambers should be emptied every day to prevent mold growth. If you use tap water or rain water, there will be deposits left as the water evaporates, and these can usually be removed by soaking with vinegar and a little scrub. If you use demineralised water you should not need to clean your humidifier chamber. It is that same stuff sold for use in irons, and car radiators and so on and is pretty cheap. Many people mistakenly refer to it as distilled water, but distilled water is different thing. It is of a far high grade of purity that is unnecessary for use in a CPAP machine, and proper distilled water is expensive. If you have a filter tap this is just as good. Hope all of that helps.

I shall try to cover the various queries in this post as succinctly as possible, but I may get lost. CPAP is supposed to lower AHI, but the AHI on your download will rarely be zero. On a download, and AHI of 5 or less is generally considered good because of the the machine measures data. It detects events using only pressure. If your are breathing well, the pressure fluctuation created by your inhalation and exhalation is very regular. When it changes at all your CPAP machine is inclined to count this an event. The manufacturers say that they have some fancy software to refine things, but generally speaking, if your breathing changes they count it. Now, this may be due to an apnoea or hypopnoea, but it may also be because you cough, roll over, twitch or anything else which causes a slight change in your breathing pattern. For this reason, the AHI stated on a CPAP download will always be an overestimate and so most people will never get zero, which is why we have the idea of anything less than 5 being OK. People with Periodic Limb Movement Disorder (similar to restless leg syndrome) will almost always have a very high AHI because they twitch a lot. For this reason they can't use an auto CPAP because it thinks the twitches are apnoeas and maxes out the pressure in an effort to stop them.

In a sleep study, apnoeas and hypopnoeas are detected by a range of sensors. It involves a drop in air flow (detected by nasal pressure and a thermister) accompanied by a decrease on oxygen saturation (detected by an oximeter) or a change in brain activity (measured by an EEG). This adds up to a bare minimum of 4 wires. However, in order to classify the type of event, the effort of your breathing muscles is measured (requiring a strap around your stomach, chest or both which is cheerfully called an inductance plethismograph - say that without your teeth in). This allows us to tell if the events are obstructive or central. Limb movements should also be measured on order to eliminate changes in breathing which are caused by leg twitches (as mentioned above). Overall, this is a lot more detailed and sensitive than just using air pressure as a guide, so this is why a proper sleep study is always considered more reliable than the download data from your CPAP machine.

OrphanAnnie, I am rather surprised that your technician told you that the data your machine records is too complicated. The software can be a bit of a mess, but the data is quite simple and not that hard to understand. I can only suggest that you call the hospital, speak to someone else who works at the sleep lab and ask them to explain the results to you. Having said that, there's not much to explain from a download, but they should still be able to answer your questions about it. That's what I do all the time at work.

Regarding your sinus problems, it will probably affect which mask you use, whether you use a humidifier and such, but it is totally independent of your sleep apnoea. Your sinuses are between your nose and mouth, but obstruction due to sleep apnoea happens at the back of your throat, so they are in separate parts of your head.

It is common (in Australia anyway) for there only to be technicians present when the study is performed. The data is then analysed by another tech and finally reviewed by a doctor. We are not allowed to discuss the results (much) with the patient in the morning after the study, however, once the specialist has reviewed that results and made a comment we are quite free to discuss them with the patient. Indeed, a large part of my role is education because that often makes a big difference in compliance with and effectiveness of treatment. In-lab studies are available in Australia completely free of charge (although there are also private facilities which are quite expensive). I understand the cost factor very well, and would simply add to be careful and know what you are getting for your money. I have met way too many people who have shelled out thousands of dollars for equipment they don't need based on a sketchy home-based study. It is possible to get home-based equipment which return basically the same data as an in-lab study (although there is no tech there to ensure data quality), you just need to keep yourself well informed.

The lowest pressure any machine can be set at is 4 (with one or two exceptions, but those machines have been out of circulation for over a decade). The ramp can be set to start at any pressure and the time it takes is also adjustable on most models. I think what Gerbil is saying, is that their CPAP is set at 10 and when they press the ramp button it drops to 8. If you have a ResMed S8 or later machine (such as Wiredgeorge) there is no ramp button, but the ramp is activated every time you start it. You should be able to get any CPAP provider to drop your ramp start pressure and probably increase the ramp time (although without knowing the model of your machine it is hard to be definite on the available functions). This does not affect the treatment level, and so it should not require a visit to the doctor (not in Australia any way).

Sometimes, but not often, central apnoea can respond to oxygen therapy, either partially or completely. It does require a proper study with full monitoring (including transcutaneous carbon dioxide monitoring) to make sure the oxygen is not causing any ill effects. Also, in some of our patients central apnoea has reduced one their heart function has improved, and they only need CPAP. Also, the increased mortality for people with low ejection fraction only applies to ASV, not standard BiPAP. Standard BiPAP may very well be effective in treating central apnoea without needing ASV and, indeed, it should be the dsefault choice. ASV was designed specifically for treating Cheynne-Stokes respiration in the setting of hypocapnea, not just as a BiLevel Swiss Army Knife. Although ASV has auto in the name, IT IS NOT and automatic BiPAP and was never designed to be one (I have spoken with the team who first deigned it).

Worth remembering that home studies can be less reliable than a proper, monitored, in-lab study. It mostly depends on which equipment they use. We use 25 sensors to measure at least 19 different parameters (some parameters use 2 sensors). Some home study kits use a few as 3 or 4, and fewer sensors means less data and therefore less reliable results. I not very familiar with healthcare in the US (Where I assume you are), but having a trusted doctor to talk to about it is also very worthwhile, as they can take you entire health history and situation into account. Some of my patients have used Secondwind CPAP with good results.

Which mask are you currently using, and which have you tried? It is a good idea to get a professional to help you with mask fit and adjustment when you first get it, as this can make a difference. My personal favourite full face masks are the Fisher & Paykel Simplus and the Phillips/Respironics Amara View. Getting the right mask and the right size can often mean that it doesn't need to be as tight or uncomfortable, and also remember that a little leak isn't the end of the world if you sleep better. Have you considered a nasal mask and chin strap? Plenty of people with high pressures (such as yours) still use nasal, and it would help with your dry mouth. Another tactic to lower the pressure (and thus improve mask fit and decrease dryness) is to find a way of staying on your side while you sleep, because some people can get away with a lower pressure while on their side. Are you sure that you are using you humidifier correctly? A lot of my patients don't.

I work in a sleep lab, and your AHI of 80 is high, but certainly not record breaking by our standards. We regularly get people with AHIs over 100 ,and I have seen a couple over 200. There is a theoretical maximum based upon the rules for scoring (analysing) sleep studies, but it is not exact. You have to have decreased respiration for at least 10 seconds for it to count (along with either a decrease in oxygen saturation of at least 3% or an observable arousal in EEG). Then, you would require a second or two to take at least one breath for the event to be over before you start the next one. If we call it 2 seconds for a breath, that gives us a theoretical maximum AHI of 300. As Dr Luisi suggested, it's worth remembering that AHI is only part of the picture.