Boosting Compliance

Heated humidification brings new levels of compliance and comfort to CPAP.

Reprinted with permission (08/19/1999) ©Home Health Care Dealer/Supplier

Heated humidification is marvelous. Its is one of the main factors in making compliance happen." Shelley Cutting, ME, director of new market development at Northwest Medical, Portland, Ore. has no hesitations when it comes to supporting this relatively new technique for improving compliance in continuous positive airway pressure (CPAP) patients. "Beyond all other means we have, heated humidification has certainly become the standard for the least invasive, best method to constantly control nasal congestion."

Cutting began using the technique approximately 5 years ago, but many respiratory therapists have only recently introduced heated humidification to CPAP patients.

Heated humidification helps eliminate the problem of nasal drying. As a CPAP delivery application, it closely resembles cool – or pass-over –humidification. An air hose leading from the CPAP unit connects to the humidifying device, where it passes over a chamber of distilled water to pick up moisture. The main hose then connects to the nasal mask. " It is pretty much a blow-by system," says Andrea Pavlak, RRT, of Boardman Medical Supply, Girard, Ohio. " The heated humidifier basically just adds a heating plate under the humidifying chamber. The heating plate is adjustable in temperature so [patients] can adjust it at home to suit their needs."

This simple system has become, in the eyes of many practitioners, the most effective of several techniques designed to combat the drying effect of CPAP.

"Absolutely, heated humidification has improved compliance in our patients," says Bob Shellenberger, CRTT, RCP, manager of respiratory care services at RX Respiratory Care, Monroeville, Pa. " Everyone that we’ve used it on so far has had symptoms improved and problems relieved."

Despite its benefits, heated humidification is often the last-resort effort for improving CPAP compliance and patient comfort. "We know that it works, but because of the cost , doctors will say, ’Try this nasal spray, try this decongestant,’ all the way down the line to pass-over humidification, which we know doesn’t work at all," Cutting says. "Finally, we get down to heated humidification.

The Price of Compliance

Several factors inhibit standard application of heated humidification of CPAP users. "Expense is the first issue I’d be concerned About," Shellenberger says. Each unit can cost as much as $500. "And second, sometimes there’s a comfort issue with the heat. It can be a little bit warmer than room temperature." Both providers note that approximately 5% of their CPAP patients use heated humidification. "Usually there’s a clinical indication as to why we’re going to proceed on to heated humidification," Shellenberger says. "A lot of them have sinus problems; they’ll have severe congestion, sinus infections, severe dryness of the sinuses. Anything like that would be an indication for us to consider heated humidification."

Recently, RX Respiratory Care has started relying on heated humidification with more and more CPAP patients. "We’re finding an increasing recommendation for switching patients to heated humidification for comfort," Shellenberger says. The company now monitors patients early – with-in 30 days – to catch indications of future noncompliance and to move to heated humidification. "We actually are more aggressive now in heated humidification as opposed to medication and other things that [clinicians have used in the past] to relieve symptoms.

The very nature of CPAP delivery suggests that heated humdification can and should play a larger role in improving compliance, according to Cutting. "What we’ve found is that with a large percentage of CPAP patients, people do not have any sinus problems prior to using CPAP, and the CPAP actually creates chronic sinus congestion," she says. "The cold air blowing through your nose causes swelling of the mucas membrane, and of course that is what creates congestion. It’s directly caused by the CPAP machine, and that’s why we have so many people who need [heated humdification]."

Research

Several recent studies also offer scientific support for expanding the role of heated humidification in CPAP use. In a series of tests performed on six normal subjects, researchers found that using room air for CPAP delivery resulted in nasal airway resistance (NAR) of more than 250% of baseline.1 Adding a cool humidifier did not affect NAR, but use of heated humdification reduced NAR at two temperature settings (p.<.001).

A second study specifically addressed the effects of heated humidification when a CPAP patient has a mouth leak.2 Eight subjects using nonhumidified CPAP displayed a 65% mean increase in nasal mucosal blood flux, which in turn increases NAR. Nasal mucosal blood flux increased by only 8% in the same subjects when heated humidification was added to their CPAP units. Mouth leaks, which occur when the patient breathes with an open mouth, cause a unidirectional airflow over nasal membranes to further exacerbate any drying effect.

Supporters of heated humidification hope these studies will lead to greater usage of the technique in CPAP delivery. "This is our first step in helping payors and even some physicians who aren’t as privy become more aware of the advantages of using heated humidification. It’s a good milestone," Cutting says. She believes scientific support will help sway payors who are hesitant to approve heated humidifiers in CPAP. "We now have a scientific basis to say, ’Look, payor, this is definitely a measure that works.’ "

Currently, 25% of CPAP patients at Northwest Medical successfully use heated humidification with their units. "We found that [patients using] heated humdification definitely have a much higher tolerance and a much better chance of being long- term user," Cutting says. But she still has a hard time convincing physicians and payors to try the technique. "The heated humidifiers are fairly expensive," Cutting says. "Patients don’t want to pay for them, therefore a lot of them don’t go out." Payors who consider heated humidification an accessory rather than a necessity find it difficult to justify the cost.

"Certainly it should be classified as an accessory, based on the fact that not every region needs it," Cutting concedes. "However, the majority of the patients do need it, and probably 85% to 90% of patients would benefit from it. Even the patients who don’t need it day to day, if they had it, they would be better off than they are."

Kathryn Olson is associate editor of Home Health Care Dealer/Supplier.

References

1. Richards D, Cistulli R, Unger R, Berrthon-Jones M, Sullivan C. Mouth leak with nasal CPAP increases nasal airway resistance. Aust NZ J Med. 1994;24.480

2. Hayes M, McGregor F, Roberts D, Schroter R, Pride N. Continuous nasal positive airway pressure with a mouth leak: effect on nasal mucous blood flux and nasal geometry. Thorax. 1995;50:1179-1182.