COMPARISON OF TWO EXPIRATORY PRESSURE RELIEF SYSTEMS OF CPAP DEVICE FOR OSA TREATMENT
Dec 27, 2012

Tsu Hui Shiao , Guang Ming Shiao

Department of Chest Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan

  

BACKGROUND

Obstructive sleep apnea (OSA) is a sleep disorder that is caused by repetitive, short-duration blockages of the upper airway, resulting in episodic cessation of breathing (apnea) or reduction in airflow (hypopnea), both of which may lead to arousal from sleep. In the United States, an estimated 9% and 24% of women and men, respectively, aged 30 to 60 years have at least mild OSA. The overall prevalence of mild and moderate OSA is estimated at 20% and 7%, respectively, in Western countries. 

Auto-adjust positive airway pressure (APAP) is the most effective non-surgical treatment for OSA. Research shows that APAP decreases daytime sleepiness, especially in those with moderate to severe OSA.

To enhance the treatment comfort of CPAP therapy among OSA patients expiratory pressure relief system (EPRS) has been adopted to several CPAP devices. PVA and C-Flex are two EPRS technology developed by APEX and Philips/Respironics Inc. respectively. In this study we compare the efficacy and treatment comfort between PVA and C-Flex systems among 25 severe OSA patients.

OBJECTIVES

Primary Aim:

To determine whether the PVA system (APEX Medical Corp., New Taipei City, Taiwan) yields similarly therapeutic benefit to OSA subjects receiving C-Flex system therapy.

Secondary Aims:

  1. To compare the AHI, RERA and oxygen desaturation index (ODI) between PVA and C-Flex systems.
  2. To compare the sleep quality and comfort between  PVA and C-Flex systems.

METHOHS

  1. This was a randomized, prospective, single blind, cross-over study of XT Auto with PVA (APEX) and REMStar Auto with C-Flex (Philips/Respironics)
  2. An overnight polysomnography to obtain data of hypnogram, respiratory events (Apnea, Hypopnea and RERA) and O2 desaturation.
  3. Questionnaire to assess patient comfort after each night study were conducted.
  4. Subject enrolled criteria

l      Inclusion criteria:

u    Severe OSA Patients with apnea hypopnea index (AHI) 40/h and is currently receiving CPAP therapy.

l      Exclusion criteria:

u    Apparent pulmonary disease, such as asthma, chronic obstructive pulmonary disease (COPD), interstitial pulmonary disease, tuberculosis, pneumonia, etc.

u    Acute cardiopulmonary, renal, or liver failure

u    Neuromuscular disorder or hypoventilation syndrome

  1. Study design.

l      Eligible outpatient subjects severity of OSA was confirmed by full Polysomnography (PSG) investigation in the Division of Clinical Respiratory Physiology of Taipei Veterans General Hospital.

l      Subjects were allocated to receive XT Auto with PVA and REMStar Auto with C-Flex under polysomnographic monitoring in a randomized order at least for two nights in the clinical sleep laboratory. 

l      All subjects should be received the APAP Therapy at least two nights, and each APAP Therapy should extended over 6 hours.

l      Questionnaire is filled out while in the next morning.

 

  1. All statistical analyses were performed by using SPSS 11.0 statistical software (SPSS Inc., USA), and use the paired t-test to calculated differences between the between PVA and C-Flex systems

RESULTS

Table1.  Patient demographics and clinical characteristics

 

 

Demographics

Clinical Characteristics

 

Gender

 

 

 

     Males

92% (23/25)

 

 

     Females

8% (2/25)

 

 

Age (years)

46.8 ± 10.3

 

 

Body Mass Index

30.3 ± 5.8

 

 

RDI

 

      70.4 ± 25.4

 

Mean SpO2

 

       72.1 ± 8.1

 

Table2. Comparison of Polysomnographic Results

Subjects (N=25)

PVA

C-Flex

P Value

Mean±SD

Mean±SD

 PVA vs C-Flex

AHI (/h)

2.39 ± 2.51

1.56 ± 2.46

NS (0.08)

RERA

2.20 ± 3.24

1.57 ± 1.67

NS (0.28)

 O2 Desaturation Index (/h)

2.17 ± 2.40

1.17 ± 1.70

SS (0.02)

Mean SpO2%

96.14 ± 1.06

96.43 ± 1.20

NS (0.10)

       

The polysomnographic results of respiratory events with PVA and C-Flex systems were shown in Table 2. Both systems were capable to control AHI (2.39±2.51 vs. 1.56±2.46  respectively, p=0.08), RERA index (2.20±3.24 vs 1.57±1.67,  p=0.28), the SpO2 (%) (96.14±1.06 vs. 96.43±1.20, p=0.10) and desaturation index (2.17±2.40 vs 1.17±1.70, p=0.02) effectively and equivalently. The Desaturation Index was slightly lower for C-Flex (2.17±2.40 vs 1.17±1.70, p=0.02).

Table3. Sleep Quality Evaluation

 

Subjects (N=25)

PVA

C-Flex

P Value

Mean ±SD

Mean ±SD

PVA vs C-Flex

Total time in bed (min)

375.43 ±15.06

378.46 ± 20.04

NS (0.40)

Sleep period time (min)

368.55 ± 16.97

370.76 ± 23.59

NS (0.54)

Total sleep time (min)

328.70 ±62.11

336.81 ± 41.38

NS (0.34)

Sleep Efficiency (%)

89.86 ± 7.86

89.15 ± 10.37

NS (0.64)

Stage Change

150.71 ± 36.90

148.26 ± 42.19

NS (0.63)

REM (% SPT)

18.28 ± 7.14

18.39 ± 8.48

NS (0.93)

SWS (%SPT)

6.10 ± 6.20

7.85 ± 7.55

SS (0.04)

Arousal Index

19.07±9.96

16.54 ± 7.89

NS (0.14)

The sleep architecture during polysomnography with PVA and C-Flex were shown in Table 3.  There were no significant difference of total time in bed (TIB), sleep period time (SPT), total sleep time (TST), sleep efficiency, number of stage change, REM content and arousal index between two systems. SWS content was slightly lower for PVA (Table 3).

Table4. Numerical rating scale of Sleep Quality and Adverse Effect

Subjects (N=25)

PVA

C-Flex

P Value

Mean ±SD

Mean ±SD

 PVA vs C-Flex

 

Sleep Quality

Sleep Depth

5±1.11

±1.33

SS(0.03)

Sleep duration

±1.17

± 1.35

NS(0.11)

Awakenings during the night

±1.54

4±1.59

NS(0.77)

Sleep Stability

5±1.12

5±1.29

NS(0.14)

 

 

 

Adverse Effect of Device

Pressure deliver from device cause patient breathing difficulty

4±1.01

4±1.19

NS(0.06)

Noise of expiratory pressure from device

4±0.87

4±0.84

NS(0.43)

Pressure change cause patient’s thoracic (chest) cavity stress

±0.85

±1.05

NS(0.27)

Awake frequently

± 1.57

± 1.45

NS(0.97)

Abdominal distention after wake up

± 0.78

± 1.05

NS(0.41)

Dryness of mouth

± 1.39

±1.72

NS(0.26)

The subjective impression of sleep quality as surveyed by the numerical rating scale (NRS) questionnaire showed no difference of sleep depth, sleep duration, frequent awakening and sleep stability between two devices. As to the adverse effect of CPAP therapy, there were also no significant difference of pressure discomfort, noise, thoracic stress, awakening due to CPAP, abdominal distention and dry mouth between two devices (Table 4).

CONCLUSION

This study shows that PVA and C-Flex systems that provide pressure relief technology are comparable in terms of alleviating respiratory events and sleep fragmentation. Both PVA and C-Flex demonstrate equivalent effective OSA therapy that in a sleep laboratory setting based on AHI, RERA and O2 desaturation index analysis. In this study, PVA and C-Flex showed  similarly beneficial effects on sleep quality by measuring of total time in bed, sleep period time, total sleep time, sleep efficiency, number of stage change, REM content and arousal index. However, SWS content was slightly lower for PVA. The subjective impression on sleep quality  and adverse effects surveyed by the numerical rating scale questionnaire showed no difference between PVA and C-Flex systems.  

Thus, XT Auto with PVA and REMStar Auto with C-Flex were shown to be substantially equivalent in performance.