The Value of Rapid Shallow Breathing Indeks in Predicting Non-invasive Mechanical
Condition: Acute Respiratory Failure
MeSH terms: Respiratory Insufficiency; Respiratory Distress Syndrome
Study type: Observational

Summary: 
      There are some criteria such as the most frequently used parameters to predict the failure of
      non-invasive mechanical ventilation, the APACHE 2 score, the presence of pneumonia and ARDS
      in the etiology, and no improvement in one hour of treatment. However, APECHE 2 score, which
      is the broadest of these criteria and includes others, is a complex scoring in which a large
      number of parameters are evaluated together, dependent on laboratory results and still leaves
      the final decision to the physician with a complete evaluation. In addition, the APACHE 2
      score is a more commonly used method for intensive care patients rather than emergency
      patients who need a quick decision. Therefore, there is a need for a fast and practical
      method that can predict NIMV failure and determine early intubation decision in the
      management of patients admitted to the emergency department with acute dyspnea. Rapid Shallow
      Breathing Index (RSBI) is a parameter calculated by dividing the respiratory rate by the
      tidal volume and is used to predict whether patients who are intubated in intensive care unit
      can be extubated successfully.

      The aim of this study is to evaluate the success of RSBI in predicting intubation and
      mortality in patients presented to the emergency department with acute respiratory failure
      and had NIMV indication.
    

Detailed description: 
      Respiratory failure is a challenging health problem that constitutes a significant part of
      emergency room visits (1). Acute respiratory failure treatment is a complex process in which
      pharmacological and non-pharmacological methods are used in combination. Non-invasive
      Mechanical Ventilation (NIMV) and Invasive Mechanical Ventilation (IMV) are life-saving
      methods commonly used in the emergency department in severe respiratory failure (2). In
      patients with severe dyspnea, NIMV improves alveolar gas exchange, with very successful
      results in selected patients (3). However, while NIMV cannot be used in patients who are
      unconscious, unable to protect the airway, have upper gastrointestinal bleeding and facial
      trauma and cannot adapt to non-invasive mechanical ventilation, these patients have IMV
      indication. Both methods are quite successful when used in selected cases. Therefore, patient
      selection is very important for NIMV and IMV (4). It is known that endotracheal intubation
      increases the risk of developing complications such as ventilator-associated pneumonia and
      sepsis. Therefore, unnecessary endotracheal intubation and invasive mechanical ventilation
      therapy are expected to increase mortality (5). On the other hand, delayed intubation
      decision is known to be an independent risk factor for increased mortality when NIMV fails
      (6) (7) (8). A method that predicts NIMV failure and enables effective mortality estimation
      may be useful in facilitating patient selection and providing appropriate treatment to
      patients. There are some criteria predicting that NIMV will fail in patients with severe
      respiratory distress and may be guiding for early intubation. The most commonly used of these
      are high APACHE 2 score, ARDS or pneumonia as the etiology of respiratory distress, advanced
      age, and no clinical improvement after 1 hour of treatment (9). However, APECHE 2 score,
      which is the broadest of these criteria and includes others, is a complex scoring in which a
      large number of parameters are evaluated together, dependent on laboratory results and still
      leaves the final decision to the physician with a complete evaluation. In addition, the
      APACHE 2 score is a more commonly used method for intensive care patients rather than
      emergency patients who need a quick decision. Therefore, there is a need for a fast and
      practical method that can predict NIMV failure and determine early intubation decision in the
      management of patients admitted to the emergency department with acute dyspnea. Rapid Shallow
      Breathing Index (RSBI) is a parameter calculated by dividing the respiratory rate by the
      tidal volume and is used to predict whether patients who are intubated in intensive care unit
      can be extubated successfully (10). In a study by Berg et al. (11) evaluating the
      endotracheal intubation and mortality rates of patients who underwent NIMV, it was found that
      the RSBI value above 105 obtained with a single measurement was significant in predicting NIV
      failure. Although this result is significant, it is not sufficient to make an early
      intubation decision. Considering that serial measurements are found to be more meaningful
      than a single measurement while predicting weaning success (12), serial measurements can
      provide more successful results in predicting intubation and mortality of patients receiving
      NIMV. Although the RSBI value obtained immediately after the initiation of NIMV is high, it
      is possible for the patient to be relieved after the patient has been treated with NIMV for a
      while and thus, the RSBI value may also decrease. For this reason, after these patients have
      been treated for a while, obtaining RSBI value once again and looking at the patient's
      response to treatment may provide more meaningful results.

      The aim of this study is to evaluate the success of RSBI in predicting intubation and
      mortality in patients presented to the emergency department with acute respiratory failure
      and had NIMV indication.
    

Intervention name(s): Rapid Shallow Breathing Index
Intervention type(s): Diagnostic Test
Intervention description(s): The RSBI is defined as the ratio of respiratory frequency to tidal volume.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The study population consisted of only patients (patients admitted to the emergency
        department with acute respiratory failure)