Feature | June 11, 2007 | Michael Addison

Evidence Mounts in Support of More Noninvasive Ventilation

Nevertheless, doubts linger over increased monitoring needs.

Noninvasive positive pressure ventilation (NPPV) has received increased attention in recent years as researchers and clinicians explore possible applications for the technology. Intubating patients and placing them on a ventilator is a well-established method for providing respiratory support, but it also carries with it an increased risk for infection or damage to the lungs. Still, much of the evidence regarding the benefits of NPPV is subject to debate and many clinicians will want to see additional research before adjusting their methods and preferences regarding ventilation options.
In order to evaluate the current situation regarding NPPV, it is important to have an understanding of the various forms of its delivery, its potential applications and the concerns over its effective implementation. Ultimately, further studies will be needed in order to address many of the remaining concerns about NPPV, while manufacturers can help address some of the implementation questions through advances in product design and technological integration.
Finding the Best Fit
Patient cooperation is an important element to ensuring effective implementation of NPPV. Therefore, the delivery method chosen for NPPV can have significant bearing on the patient’s level of comfort and the success of the treatment. Volume ventilator support and pressure-controlled ventilation are two options doctors can select when deciding how to deliver NPPV. As the name implies, volume ventilator support works by sending a predefined volume of air through the patient’s airways. Studies have noted that this method can result in more complaints about discomfort, as the inspiratory pressure tends to be higher. In addition to patients finding it more cumbersome to breath, volume-controlled ventilation can result in more air leaks.
When receiving pressure-controlled support, patients seem to have a better time at tolerating the delivery of air. This may be due to the fact that pressure-controlled ventilators respond to the patient’s breathing patterns and adjust the air volumes accordingly. Clinicians have found that they can have more control over the respiration process when using these devices, while also providing greater comfort to patients. Bilevel Positive Airway Pressure (BiPAP) devices allow clinicians to separate pressure levels for inspiration and expiration, thus adding yet another level of control for the clinician. This dynamic form of NPPV delivery has been an important innovation.
Also falling under the category of pressure-controlled ventilation is continuous positive airway pressure (CPAP). This form of noninvasive ventilation has become widely known as a ventilation mode for home use. It is often employed in the treatment of patients living with obstructive sleep apnea (OSA). The continuous pressure provided through CPAP devices can reduce the work of breathing for sleep apnea patients and keep their airways stented throughout the night.
Expanding Clinical Applications
A recent article in Critical Care Clinics by Timothy J. Barreiro and David J. Gemmel discussed several benefits of NPPV in regard to improving clinical outcomes. In addition to treating patients with respiratory diseases, NPPV can also help improve outcomes related to neuromuscular diseases and heart failure. For patients with neuromuscular disease, NPPV has been shown to slow the rate of deterioration in lung function. The article cited a study where quality-of-life scores for certain patients with neuromuscular disease increased by 30 percent, and showed a cost savings of $50,000 per quality-of-life adjusted year.
Then there is also the role NPPV can play in helping patients with cardiac complications. For patients with congestive heart failure (CHF) who have experienced acute pulmonary edema, NPPV has helped reduce the strain of breathing while improving their oxygenation. One study noted that BiPAP helped reduce intubations for CHF patients by nine percent. Thus, BiPAP can play an important role in facilitating recovery and reducing additional hospital stays.
Clinicians have often treated OSA with CPAP therapy in order to address sleep disturbances associated with respiratory distress. However, there is also evidence that CPAP can play a role in preventing cardiac arrhythmia. Studies have found that patients with OSA are at a higher risk of cardiac arrhythmia, and this risk is associated with oxygen desaturation. Hence, CPAP support for nighttime breathing for these patients may provide both respiratory and cardiac benefits.
Moreover, there is evidence supporting the use of CPAP and other forms of noninvasive ventilation for neonatal patients. Possible damage to the lungs and airways is a major concern during the treatment of infant patients. Earlier this year, an article appearing in Clinics in Perinatology by Dr. Sherry E. Courtney and Dr. Keith J. Barrington indicated that CPAP can reduce or prevent apnea and possibly eliminate the need for intubation for neonatal patients. Other forms of noninvasive ventilation could have a similar effect. However, more research is required to determine which system is best suited for each case.
Research continues to show an expanding range of applications and benefits from NPPV. More studies are necessary to determine which delivery method is best depending upon the patient’s circumstances, so we can expect increased dialogue about these issues.
Implementation Costs
One of the arguments in favor of more widespread use of NPPV is that it can help prevent intubation, thus reducing the length of the patient’s hospital stay and saving time and money. Intubated patients also have a greater risk of acquiring a nosocomial infection and can experience scarring of the lungs, which can have a negative impact on recovery. These are important advantages that NPPV can offer over intubation. However, NPPV still presents its own workflow challenges.
Physicians and hospital staff have noted that patients receiving NPPV require more continuous monitoring than those who have been intubated. First of all, there can be issues concerning patient compliance. Patients receiving NPPV often complain about difficulty breathing, as adjusting to the airflow can be awkward. Clinicians must spend time ensuring that there is a proper fit to prevent air leakage.
Furthermore, clinicians must constantly stay abreast of the patient’s respiratory status in order to know if the airflow must be modified or if the patient may ultimately require intubation. Some believe this additional monitoring is a poor allocation of resources and can detract from the hospital staff’s other duties. Intubated patients do not require this same type of fine tuning. Also, if an intubated patient is sedated, then patient compliance becomes a nonissue.
It is unclear how much additional time and resources NPPV demands. One study on this issue indicated that nurses and respiratory therapists only spent an additional 24 minutes during the first eight hours of treatment of patients on NPPV when compared to intubated patients. Meanwhile, another study implied that monitoring requirements were much more intensive. It indicated that patients receiving NPPV must have a nurse monitoring them at their bedside 91 percent of the time.
Given the disparity in such research findings, it is understandable that there continues to be some debate about the potential resource allocation challenges posed by NPPV. When considering concerns related to monitoring requirements, it is important to note that design innovations will probably have a significant role to play in addressing these issues. As manufacturers offer more comprehensive and better integrated monitoring solutions, hospital staffs will experience improved workflow efficiency in relation to NPPV. There are already systems that are more leak tolerant and do not require as much attention to breathing interface. This is an example of how technological innovations may help put many resource-consumption concerns to rest.

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