The Protective Role of the Nose During Acute Exposure to Passive Smoking.
Condition: Second Hand Smoke Exposure
Study type: Interventional
Phase: Phase 1

Summary: 
      The aim of this study was to compare the acute effects of second hand smoke exposure between
      nasal and oral breathing and to assess the potential protective role of the nose during acute
      exposure, in exposure conditions similar to those within a bar where smoking is permitted.
    

Detailed description: 
      Analysis of the laboratory testing:

      The measurement of NO for the respiratory tract was performed with a Ecomedics CLD 88spNO
      analyzer as follows: the examinee performed tidal breathing with a closed nose, through a
      special mouthpiece and then took a deep breath and exhale steadily with a flow of 50ml/sec.
      After 3 attempts, during which we obtained an exhaled NO measurement each time, until we
      obtained a reliability index CV <10%.

      For the oscillometry (IOS) of the respiratory tract the Master Screen IOS VIASYS was used,
      the examinee breathed quietly through the mouthpiece with his/her nose closed for a period of
      1 minute. In this way we measured the impedance Z at 5 Hz, the resistance to 5,10,20 Hz
      respectively, the reactance in 5,10,20 Hz respectively, the central and peripheral airway
      resistance and resonant frequency.

      Rhinomanometry was done by the Master Screen IOS VIASYS system, the examinee breathed calmly
      through the examined nostril, while the other was closed, 5 breaths per attempt were
      performed. After 3 attempts for each nostril, we assessed the average inspiratory resistance
      for each nostril separately.

      The plethysmography took place on the Master Screen Body of VIASYS, the door of the Body was
      closed as well as all the doors of the room and without the presence of motion in the test
      room. The subject performed calm breaths with a closed nose, through the mouthpiece and then
      took a deep breath, followed by deep exhalation. At the end of the effort we had values for
      the total lung capacity (TLC), residual volume (RV), airway resistance (R), vital capacity
      (VC), the functional residual capacity (FRC), Exhaled residual volume (ERV) and the ratio RV
      / TLC. This was repeated 3 times and one was selected to be the most representative.

      The P.100 was performed through the Master Screen Body of VIASYS with the door of the Body
      Box opened. The volunteer was performing calm breaths with a closed nose, through the
      mouthpiece, during which a shutter blocked the flow. The obtained value of the pressure was
      the one that developed in the first second of inhalation with the shutter down is noted. This
      repeated 3 times and one selected to be the most representative.

      Spirometry and the flow-volume curve were assessed with a Master Screen Body of VIASYS with
      the door of the Body Box opened as follows: The subject performed tidal breathing with a
      closed nose, through the mouthpiece, and then took a sharp deep breath, which was followed by
      sharp deep exhalation, and the test ended with deep inhalation. At the end of the effort we
      had values for forced vital capacity (FVC), the violent expiratory the first volume 1 (FEV1),
      the ratio FVC/FEV1%, peak expiratory flow (PEF) and mesoexpiratory flow in peripheral airways
      than 25% to 75% of vital capacity. This was repeated 3 times and one was selected to be the
      most representative.

      The assessment of the type of breathing during exposure to secondhand smoke was performed
      through the VIASYS Respitrace. The protocol was as follows: The volunteer breathed calmly
      over 20 times with the mouth closed and once with a closed nose, while wearing two rubber
      bands, one on the chest and one to the abdomen, which incorporates electrodes. The waveform
      of the breath in the thorax, abdomen and the average of these was recorded in real time.
      Also, for every breath we had values for the inspiratory time, expiratory time, total time,
      the participation rate of the chest, the participation rate of the ventricle, the peak
      inspiratory flow (Pif), the mean inspiratory flow (Mif), and the flow-volume curve and the
      analysis chart of each breath in the thoracic and abdominal component.
    

Intervention name(s): exposure to second hand smoking
Intervention type(s): Other
Intervention description(s): The duration of the exposure to second hand smoke both days was for 20 minutes within a 250mgr/m3 concentration box room. A smoking machine was used, which mimics the smoker (up to 6 breaths per minute in tobacco volume 80ml for each inhalation). The exposure was sometimes with closed mouth and others with closed nose in random sequence.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Prevention
Keywords: nasal breathing, oral breathing, secondhand smoking,