Noninvasive ventilation (NIV) delivered using a ventilator and a mask that covers the face during exercise decreased dynamic hyperinflation (DH) and increased exercise duration when compared to no NIV for patients with extremely severe and severe chronic obstructive lung disease (COPD), a small, randomized, crossover trial has indicated.
The endurance duration was increased when NIV was used with either standardized expiratory positive pressure (SEPAP) or the more complex individual titrated TEPAP the study also revealed.
“DH” is when the patient is unable to fully exhale before they need it again. In the course of exercise, when they require more, they end up with an increasing volume at the end of their expiration. Clancy Dennis, a student at the University of Sydney, Australia, told Medscape Medical News via email.
“Once breathing volume reaches a critical threshold breathing becomes increasingly difficult and exercise typically ceases rapidly. So, by using NIV to assist people with COPD breathe bigger breaths and with less energy expended as well as being less hyperinflated at [test timeand, in the end, performed more exercise,” he added.
The study was published online 1st December 2021, in Chest.
Endurance Test of the Cycle
A total of 19 patients were part of the study. Patients were attending an outpatient pulmonary rehabilitation center in Australia or an inpatient rehabilitation center in Germany. Patients were diagnosed with COPD and given an FEV /FVC of 0.7 FEV 150% predicted. They were then asked to complete three endurance cycle exercises at 75 percent of their maximum rate during the incremental cycle test.
Patients exercised without NIV, NIV with SEPAP and NIV with TEPAP, as researchers explain. NIV with SEPAP provided EPAP 5 cm H 2O for all participants. NIV with T-EPAP delivered an EPAP individualized to maximize inspiratory capacity (IC) at rest for each participant. “IC was used as a proxy measure of DH and was determined by instructing the patient to breathe in fully without hesitation from the current end-expiratory lung volume (EELV) each minute during exercise.” Dennis and colleagues elaborate.
Results With NIV
The difference in exercise duration between S-EPAP and NIV was 152 seconds ( P =.003). Similarly, the average difference in the duration of exercise time with NIV & T-EPAP was 145 seconds ( P < .0001) Both of them in favor of NIV. The researchers conclude that there was no difference in NIV using SEPAP and without T-PAP.
Dennis was asked whether it was difficult to utilize NIV in COPD patients who need to exercise. He said it is not complicated when there is a competent physician and a patient who is comfortable with NIV. He explained, “It’s akin starting CPAP [for sleep apnea]” However, this trial was the first time NIV had been used before. It turned out to be a learning opportunity.
However, “people use CPAP and NIV at night, and are very capable of using all of the equipment,” he said, “and people with hyperinflation said they felt that NIV helped breathe more easily so for those who do utilize it, they could experience a significant improvement in breathlessness. This is, in my opinion, the most important point for the patient,” Dennis emphasized.
The study’s limitations include the fact that there was no NIV sham was used.
A minor, but significant effect?
Kylie Hill, PhD at Curtin School of Allied Health in Perth, Australia and Thomas Dolmage, MSc at the West Park Healthcare Centre in Toronto, Ontario commented on the findings in an editorial. They believe that the current study contributes to understanding how NIV can enhance endurance for people suffering from COPD. Although the editorialists weren’t convinced that NIV was the sole reason for the reduction in DH that was observed in this study, “the clinical implications of the study…and other studies of this kind is the role NIV may have to enhance exercise training,” they suggest.
As Hill and Dolmage explain that as high as 40% of patients with COPD suffer from a lack of improvement in exercise tolerance when subjected to standard exercise training. “It is in this regard that we need to put in the context of the benefits of high-intensity exercise and the change in endurance that was observed with NIV in this study,” they observe. While an 1.5-minute variance in median tolerance does not seem like much, “an effect of this magnitude at very high intensity would translate to an significant effect at lower intensities that are utilized in a workout,” Hill and Dolmage highlight.
For instance, exercise that could be tolerated for 10 minutes without NIV could be tolerated for in excess of 15 minutes using NIV, whereas 20 minutes of exercise without NIV could be tolerated for the rest of time with NIV, they say. According to the editorialists, it is reasonable that specialty rehabilitation programs for pulmonary function could offer NIV as an adjunct on a case by individual basis.
Kill and Dolmage recommend that “willing and competent clinicians are able to control the setting of the ventilator and titration pressures in the course of exercise.” However, they caution that it’s not known how long NIV can last to ensure optimal training adaptation.
The editors and authors have not disclosed any financial relationships.
Chest. Online publication on December 1st, 2012. Abstract
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