Luke Sullivan's presentation to the 2014 Academy for Healthcare Science Congress

1. Luke Sullivan
Chief Respiratory Physiologist
West Hertfordshire Hospitals Trust

2.  Sleep breathing disorder in which the upper airway repeated
collapses due to reduced upper airway dilator muscle activity
 Occlusion of the airway causes hypoxia and hypercapnia to
develop, thus increasing respiratory drive
 Airway reopens at the cost of the sufferers arousal resulting
in a poor quality, fragmented sleep

3.  Prevalence
◦ Affects 4% men and 2% women (Young et al, 1993)
◦ Affects up to 77% of Obese adults (O’Keefe and Paterson, 2004)
 Symptoms
◦ Daytime sleepiness
◦ Fragmented sleep
◦ Witnessed events
◦ Loud snoring
◦ Nocturia
◦ Palpitations
◦ Dry mouth on awakening
 Associated risks
◦ Hypertension
◦ Type 2 diabetes
◦ Cardiovascular disease
◦ Cor Pulmonale
◦ Road traffic accidents

4.  Objective measures
◦ Apnoea/ hypopnoea index (AHI)
 Number of times per hour the airway closes or partially closes resulting in an
arousal
 Often relates closely to the ODI
◦ Oxygen desaturation index (ODI)
 Number of oxygen desaturations of ≥4%
 American association of sleep medicine
(AASM) guidelines now score ≥3%
 Subjective measures
◦ Epworth sleepiness score (ESS)
 Patient scores how likely they are to doze in certain situations
 Score of ≥12 often taken as significant daytime sleepiness
Severity of OSA AHI
Normal <5/hour
Mild 5-14.9/hour
Moderate 15-29.9/hour
Severe ≥30/hour

5.  Continuous Positive Airway Pressure (CPAP)
 Mandibular Advancement Device (MAD)
 Surgical
 Weight loss

6.  Applying a quantifiable external load to the
inspiratory muscles
◦ Weight lifting for inspiratory muscles
 Promoted as improving inspiratory muscle strength
and consequently exercise performance
 Benefits to patients with respiratory disease
(Scherer et al, 2000)
 Proven to increase maximum
inspiratory pressure (MIP)

7.  MRI of upper airway after IMT shows signs of muscle
activation on acute level (Howe et al. 2007)
 Didgeridoo playing for subjects with OSA improved AHI
and daytime somnolence (Puhan et al. 2006)
 Oropharyngeal exercises for subject with OSA improved
AHI and daytime somnolence (Guimaraes et al. 2009)
 Normocapnic hyperpnea with a Spirotiger IMT reduced
snoring in otherwise healthy adults (Furrer et al. 1998)

8.  Reduce the AHI, ODI and daytime sleepiness
(ESS)
 Evaluate IMT as an alternative treatment for
OSA that would provide sufferers with an
option that avoided the use of equipment in
bed

9.  Participants
◦ Nine adult males (age = 57.8 ± 2.9yrs; Body mass index (BMI) = 28.7 ± 0.5kg/m²)
◦ All diagnosed with OSA through multichannel home sleep study (HSS)
◦ All had negative attitude towards CPAP treatment
 Inclusion
◦ AHI of ≥15/hour
 Exclusion
◦ Unable to perform spirometry, MIP and IMT correctly
◦ Failure to achieve the minimum compliance level
 Intervention
◦ 6-weeks of IMT
◦ 30-rep max, twice daily (McConnell and Griffiths, 2010)
◦ Complete diary card of intensity and usage
 Measurements taken pre and post intervention include;
◦ Multichannel HSS (SpO2, ODI and AHI)
◦ Height, weight, BMI, blood pressure and collar size
◦ Spirometry and MIP
◦ Epworth sleepiness score and snore score
◦ HSS was analysed by same physiologist pre and post intervention (unaware of intervention)
 Statistical analysis
◦ Paired t-tests used to analyse HSS data, anthropometric measurements and lung function tests
◦ Mann Whitney U test used to analyse questionnaires

10. Pre IMT Post IMT Change in mean
Group size (n) 6
Age (years) 57.8 (7.4)
Height (cm) 173.2 (4.2)
Weight (kg) 86.3 (7.2) 86.0 (7.8) -0.3 (1.6)
BMI (kg/m²) 28.7 (1.1) 28.6 (1.4) -0.1 (0.5)
Systolic BP (mmHg) 119.5 (17.4) 118.2 (17.0) -1.3 (7.5)
Diastolic BP (mmHg) 73.8 (5.1) 70.5 (6.9) -3.3 (2.3)*
Collar size (cm) 41.8 (1.7) 41.8 (1.3) 0 (0.6)
Epworth score 8.5 (3.5) 8.3 (2.9) -0.2 (1.1)
FEV1 (L) 3.3 (0.4) 3.2 (0.5) -0.1 (0.2)
PEFR (L/s) 10.5 (1.6) 10.6 (1.8) 0.1 (0.7)
MIP (kPa) 10.6 (2.3) 12.4 (1.6) 1.8 (1.0)**
ODI 29 (18.3) 22.8 (9.7) -6.2 (10.4)
Mean SpO2 93.5 (0.8) 93.6 (1.2) 0.1 (1.0)
AHI (events/hour) 43.7 (17.5) 24.2 (10.2) -19.5 (12.3)*
Numbers are means (SD) except for absolute values. BMI, body mass index; BP, blood pressure; Epworth score, scale of 0-
24 indicating daytime somnolence when ≥12; FEV1, forced expiratory volume in one second; PEFR, peak expiratory flow rate;
MIP, maximum inspiratory mouth pressure at residual volume; ODI, oxygen desaturation index; SpO2, oxygen saturations via
pulse oximetry; AHI, apnoea/ hypopnoea index. All pulmonary function tests were within normal limits (Quanjer et al., 1993).
*p<0.05 significantly different from baseline, **p<0.01 highly significant difference from baseline.

11.  Six subjects completed the study
 Group AHI dropped (p<0.05)
 Group MIP increased (p<0.01)
 Group diastolic blood pressure (BP) dropped (p<0.05)
 Group Epworth sleepiness score did not drop significantly
◦ This was supported by qualitative data taken from participants
◦ Potentially due to the short effect time
◦ Participants were not excessively sleepy
 The ODI did not significantly reduce
◦ Drop of 6.2 (10.4)/ hour from 29 (18.3)/ hour to 22.8 (9.7)/ hour (21% drop)
◦ Possibly due to a reduction in hypopnoeas without a corresponding ≥4% drop in SpO2

12.  Group AHI dropped
by a mean value of
19.5 ± 6.1/hour
(p<0.05)
 44.7% drop in AHI
 Reduced group
severity from severe
to moderate (43.7 ±
8.8 – 24.2 ±
5.1/hour)

13.  Group MIP increased by mean value of 1.8 ± 1.0kPa (p<0.01)
◦ Unsurprising given this is devices primary purpose
◦ Method of checking compliance
95% Bonferroni Confidence Intervals for StDevs
MIPS POST
MIPS PRE
7654321
Data
MIPS POST
MIPS PRE
15141312111098
F-Test
0.594
Test Statistic 2.10
P-Value 0.436
Levene's Test
Test Statistic 0.30
P-Value
Test for Equal Variances for MIPS PRE, MIPS POST
Fig. 2. Group mean ± SD maximum inspiratory pressures (MIPs) data, pre and
post inspiratory muscle training (IMT) intervention. Paired t-test showed p<0.01
(highly significant difference).

14.  Group diastolic blood pressure (BP) dropped by a mean value of 3.3
± 1.2mmHg (p<0.5)
◦ Both IMT and reduced AHI have shown to reduce BP (Pankow et al, 2003; Ferreira et
al, 2011)
◦ Systolic BP reduced but not significantly
95% Bonferroni Confidence Intervals for StDevs
Diastolic BP Post
Diastolic BP Pre
2015105
Data
Diastolic BP Post
Diastolic BP Pre
8075706560
F-Test
0.291
Test Statistic 0.55
P-Value 0.529
Levene's Test
Test Statistic 1.25
P-Value
Test for Equal Variances for Diastolic BP Pre, Diastolic BP Post
Fig. 3. Group mean ± SD diastolic blood pressure (BP), pre and post inspiratory
muscle training (IMT) intervention. Paired t-test showed p<0.05 (significant difference).

15.  Participants experienced a less disturbed sleep
◦ Likely to be due to the training effect of resistive inspiratory loading strengthening
the upper airway dilator muscles as suggested in similar studies.
 Balance of pressures concept
◦ Airway patency is dependent on the balance between collapsing intraluminal
pressures and stabilising forces of upper airway dilator muscles
◦ Neural drive is reduced in sleep creating optimum opportunity for airway collapse
◦ Therefore there is increased importance on the intrinsic properties of the airway wall
to avoid collapse
◦ The decrease to AHI would suggest IMT was able to exert its influence on upper
airway dilator muscles by improving passive tone, resulting in pharyngeal wall
stiffness
 Better compliance in married men
◦ Compliance still not great
◦ 2/3 participants completed the study

16.  Comparison with MAD
◦ Similar reduction to AHI
◦ 39% to 42% (Hoffstein, 2007; Chan et al, 2007; Clark, 1996)
 Comparison with CPAP
◦ IMT is not as effective for reducing AHI or daytime sleepiness
◦ CPAP reduces AHI <5/hour from all severities
 Advantages include
◦ no need to wear equipment in bed
◦ reduced daily training time from similar studies
IMT reduced AHI by 44.6%

17.  IMT improved objective measurements of OSA severity
suggesting it could be a promising alternative treatment
for OSA
◦ Most likely due to strengthening of upper airway dilator
muscles however the causal reason was not determined from
this study
 CPAP remains the gold standard treatment for OSA
 IMT offers an alternative treatment that avoids the use
of equipment in bed
 Further work needed in this area

18.  Improvements to the current study
◦ Larger sample size
◦ Control group
◦ Longer intervention period
◦ Stricter compliance
◦ Full polysomnography (PSG) to score AHI
 Similar studies
◦ Effect on simple snorers
◦ Multi-pronged treatment
 with MAD
 with weight loss therapy
◦ Split up causes of OSA for treatment
 collar size vs retrogonathia

19. Any Questions?

20.  Brouillette, R. T., Thach, B. T. (1979) A neuromuscular mechanism maintaining extrathoracic airway patency. Journal of applied physiology. 46. 772-779.

 Chan, A. S., Lee, R. W., Cistulli, P.A. (2007) Dental appliance treatment for obstructive sleep apnoea. Chest. 132 (2). 693-699.

 Clark, G.T., Blumenfeld. I., Yoffe. N., Peled. E., Lavie. P. (1996) A crossover study comparing the efficacy of continuous airway pressure with anterior mandibular positioning
devices on patients with obstructive sleep apnoea. Chest. 109 (6). 1477-1483.

 Ferreira, J. B., Plentz, R. D., Stein, C., Casali, K. R., Arena, R., Lago, P. D. (2011) Inspiratory muscle training reduces blood pressure and sympathetic activity in hypertensive
patients: A randomised control trial. International journal of cardiology. [Epub ahead of print].

 Furrer, E., Bauer, W., Boutellier, U. (1998) Treatment of snoring by training of the upper airway muscles. American journal of respiratory critical care medicine. 157, A284.

 Guimaraes, K. C., Drager, L. F., Genta, P. R., Marcondes, B. F., Lorenzi-Filho, G. (2009) Effects of oropharyngeal exercises on patients with moderate obstructive sleep apnoea
syndrome. American Journal of Respiratory Critical Care Medicine. 179 (10). 962–966.

 Hoffstein, V. (2007) Review of oral appliances in sleep disordered breathing. Sleep breathe. 11 (1). 1-22.

 How, S. C., McConnell, A. K., Taylor, B. J., Romer, L. M. (2007) Acute and chronic responses of the upper airway to inspiratory loading in healthy awake humans: An MRI study.
Respiratory Physiology and Neurobiology Journal. 157, 270-280.

 O’Keefe, T., Paterson, E. J. (2004) Evidance supporting routine polysomnography before bariatric surgery. Obesity surgery. 14. 23-26.

 Pankow, W., Lies, A., Nabe, B., Becker, H. F., Ploch, T., Lohmann, F. W. (2003) Continuous positive airway pressure lowers blood pressure in hypertensive patients with
obstructive sleep apnoea. Somnologie. 7 (1). 17-22.

 Puhan, M. A., Suarez, A., Lo Cascio, C., Zahn, A., Heitz, M., Braendli, O. (2006) Didgeridoo playing as alternative treatment for obstructive sleep apnoea syndrome: Randomised
controlled trial. British Medical Journal. 332, 266-270.

 Scherer, T. A., Spengler, C. M., Owassapian, D., Imhof, E., Boutellier, U. (2000) Respiratory muscle endurance training in chronic obstructive lung disease. American Journal of
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 Young, T., Palta, M., Dempsey, J., Skatrud, J. M., Weber, S., Badr, S. (1993) The occurance of sleep-disordered breathing among middle-aged adults. New England Journal of
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