Investigation of Predictive Indices to Objectively Guide Choice of CPAP Interface
Condition: Obstructive Sleep Apnea of Adult
MeSH terms: Sleep Apnea, Obstructive
Study type: Interventional

Summary: 
      Obstructive sleep apnea (OSA) is a prevalent disease, and one that is associated with
      significant negative impact on long-term survival. There is convincing evidence that
      treatment of OSA can improve outcome in patients with cardiovascular disease, improve blood
      pressure and blood glucose control, and improve the overall metabolic syndrome. Treatment is
      usually with continuous positive airway pressure (CPAP). However, many patients face problems
      with their CPAP interfaces, affecting their compliance and response to treatment. Proper mask
      fit is important in decreasing air leak and increasing comfort, thus leading to better
      compliance. Currently, the choice of interfaces depends mainly on the experience of the sleep
      disorder unit (SDU) technicians. Unsuitable choice of interface not only affects response to
      treatment but also increases medical costs when interfaces need to be replaced to better
      fitting ones. It is thus important to develop selection criteria to objectively guide the SDU
      technicians in choosing the suitable interfaces. The objective of this study is to study the
      facial profile of patients and look for predictive indices that can be used to objectively
      guide the choice of appropriate interfaces. Frontal and side profile photographs of patients
      will be taken and facial measurements will be recorded. Patients will then be given a one
      monthly trial of each of the 3 interfaces (nasal masks, oronasal masks, nasal cushions) in a
      randomised order. The patients' subjective perception of each of the interface will be
      assessed and patients will nominate their preferred interface at the end of the trial. The
      amount of leak and the hours of adherence for each type of interface will also be analysed. A
      multinomial logistic regression analysis will then be done to look for facial measurements
      that will predict the interface that patients will be most satisfied with.

      Hypothesis That measurement of facial structures and clinical features will be able to
      predict the best-fit CPAP interface for each patient.

      Study Objective

        -  To determine anthropometric facial measurements and clinical factors important in
           achieving a good interface fit for each patient

        -  To derive a prediction rule or equation that will be able to accurately predict which
           interface a patient should be prescribed
    

Detailed description: 
      This clinical research will be a prospective crossover trial in which frontal and side facial
      profile photographs of patients will be taken and facial measurement will be recorded
      including the height and width of the face and nose. Body Mass Index (BMI), Apnea Hypopnea
      Index (AHI) and Epworth Sleepiness Score(ESS) will be recorded. Baseline symptoms of mouth
      breathing and nasal congestion will also be assessed. Patients will undergo a quick 5minute
      trial of the interfaces at CPAP setting of 6cm H2O and give feedback of their preferred
      interface and satisfaction of each interface (Visual analogue scale) at the end of the quick
      trial. Patients will then be given a one month trial of each of the 3 interfaces (nasal
      masks, oronasal masks, nasal cushions) in a randomised order. For purpose of standardisation
      to avoid confounders, humidification and auto-titrating CPAP (autoPAP) mode of ventilation
      will be used in all patients. The brand of interfaces and CPAP devices used will also be
      standardised. This standardised CPAP treatment will be provided free of charge to patients
      during the duration of the study (3 months). The patients' subjective perception of each of
      the interface will be assessed with a visual analogue scale to assess level of satisfaction.
      Patients will nominate their preferred interface at the end of the trial. The amount of leak
      and the hours of adherence to CPAP for each type of interface will also be analysed by
      downloading data from the CPAP devices. A multinomial logistic regression analysis will then
      be done to look for facial measurements and factors that will predict the interface that
      patients will be most satisfied with.
    

Intervention name(s): CPAP interfaces
Intervention type(s): Device
Intervention description(s): All patients in study underwent crossover prospective trial of the same 3 types of CPAP interfaces (nasal mask, oronasal mask, nasal pillows) in randomized order. Trial was 1 month duration for each interface.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Prospective crossover trial. All patients will undergo a one month trial of each of the 3 interfaces (nasal masks, oronasal masks, nasal cushions) in a randomised order.
Masking: None (Open Label)
Primary purpose: Treatment