Respirator and Breathing Compartments
Condition: Face Mask Squeeze; Respiratory Complication
MeSH terms: Respiratory Aspiration
Study type: Observational

Summary: 
      The purpose of this study was to compare breathing pattern and involvement of individual
      breathing compartments (IBC) with and without filtering facepiece respirator (FFR) during
      rest and exercise.
    

Detailed description: 
      The study involved 21 students majoring in physical education and sports. All subjects were
      physically active, engaging in approximately 260 minutes of physical activity per week, and
      they possessed a high level of fitness. Inclusion criteria required participants to be free
      from injury, capable of providing written consent, and within the age range of 19 to 26
      years. Exclusion criteria included individuals who smoked or had chronic pulmonary or cardiac
      diseases. This research received approval from the Ethics Committee at the Faculty of
      Education, University of South Bohemia, Reference Number: 002/2018. All procedures conducted
      within the study adhered to the ethical standards outlined by the Institutional Research
      Committee and the principles of the Helsinki Declaration.

      Protocol:

      Participants were instructed to visit the laboratory on two occasions to complete two
      separate tests during each session, specifically the Opto-electronic plethysmography (OEP)
      test during resting in a standing position and the OEP test during a Graded Exercise Test
      (GXT). The time interval between the testing days was three days. Participants were randomly
      assigned to two groups using randomizer.org. The first group performed three tests while
      wearing a Face-Fit Respirator (FFR), while the second group performed the tests without the
      mask. During the second visit, participants switched to the opposite condition. The N95
      respirator was employed in this study as the gold standard for protection against aerosol
      transmission, particularly during the COVID-19 pandemic. A new mask was used for each test.
      In the Standing Test (STD), participants were instructed to maintain a stationary standing
      position and engage in spontaneous, quiet breathing without speaking or altering their
      posture while OEP data was collected. The first two minutes were designated as an adaptation
      period, followed by data collection for an additional three minutes. In the context of the
      Graded Exercise Test (GXT), OEP data was collected during the final minute of each
      three-minute stage.

      Opto-Electronic Plethysmography:

      The analysis of breathing patterns and volumes of chest wall compartments was conducted using
      opto-electronic plethysmography (BTS Bioengineering, Milan, Italy). This device comprises
      eight cameras, with five positioned anteriorly and three posteriorly relative to the
      participant. Additionally, 89 reflective markers were affixed to the participant's chest,
      abdomen, and back to track movements of the trunk. This technique has previously demonstrated
      validity in both resting and maximal exercise conditions.

      The contributions of each breathing compartment (VRCp - pulmonary rib cage, VRCa - abdominal
      rib cage, VAb - abdomen) were determined by calculating the difference between
      end-inspiratory and end-expiratory volumes. The specific methodology for calculating chest
      wall kinematics using OEP has been detailed in prior research.

      Graded Exercise Tests:

      To complete this study, participants were required to undergo two maximal graded exercise
      tests (GXT) on separate days, one with the use of a Face-Fit Respirator (FFR) and one
      without. After three minutes of warm-up walking (2.7 km/h, 10% incline), participants
      performed the Bruce Protocol until exhaustion. The Bruce Protocol was conducted on a
      treadmill (Lode Valiant 2 Sport, Lode B.V., Groningen, Netherlands). All tests were conducted
      at the same time of day to mitigate the influence of circadian rhythms. Immediately following
      the completion of the test, participants provided ratings on the Modified Borg Dyspnea Scale,
      which ranges from 0 to 10, to assess breathlessness.
    

Intervention name(s): filtering facepiece respirator
Intervention type(s): Other
Intervention description(s): Graded exercise test with filtering facepiece respirator
Observational model: Case-Crossover
Time perspective: Cross-Sectional
Sampling method: Probability Sample
Study population: 
        Students of physical education and sport
      
Keywords: optoelectronic plethysmography; breathing compartments; N95; graded exercise test