Assessment of Cough Strength in Patients With Tracheostomies
Condition: Mechanical Ventilator Weaning
MeSH terms: Cough
Study type: Interventional

Summary: 
      The investigators propose to assess cough strength in patients undergoing spontaneous
      breathing trials in the Intermediate Intensive Care Unit (IICU) and compare their cough
      strength under two conditions,

        1. Tracheostomy cuff inflated: cough strength will be measured with the tracheostomy cuff
           inflated and the patient coughing through the tracheostomy tube.

        2. Tracheostomy cuff deflated: cough strength will be measured with the tracheostomy cuff
           deflated and the patient coughing around the tracheostomy tube, through their mouth..

      The investigators hypothesize that patients will have a stronger cough when they can use
      their vocal cords.
    

Detailed description: 
      When a patient has recovered from the initial respiratory insult which precipitated
      respiratory failure, the patient may need a prolonged period of time to wean completely from
      mechanical ventilation.

      One method of weaning from mechanical ventilation involves having the patient breath
      spontaneously without the assistance of the ventilator. This is referred to as a spontaneous
      breathing trial. Over time, the duration of spontaneous breathing is gradually increased
      until the patient is able to breathe entirely on their own. Traditionally, the tracheostomy
      cuff has been kept inflated until the patient can breathe entirely on their own (2,3).

      A recent study has assessed the effect of deflating the tracheostomy tube cuff on weaning
      from mechanical ventilation (4). Patients, who required prolonged mechanical ventilation and
      had a tracheostomy, were weaned using a T piece trial. They were randomized to two groups:
      the control group had the tracheostomy cuff kept inflated; the study group had the
      tracheostomy cuff deflated. The study group, with the cuff deflated, had a shorter time to
      weaning from the ventilator, fewer respiratory infections and improved swallowing. This was
      attributed to an increase in the effective airway diameter, which would decrease the
      resistive work of breathing. The authors did not comment on the effect cuff deflation may
      have on coughing and clearance of secretions.

      It is postulated that patients can cough more effectively when he/she can use their vocal
      cords to generate a cough as opposed to coughing through a tracheostomy tube where the vocal
      cords are bypassed. It has been previously demonstrated that patients have a stronger cough
      after the tracheostomy tube has been removed as compared to when the tracheostomy tube is in
      place (5).

      Patient population

      The study group will include all adult patients in the IICU, on prolonged mechanical
      ventilation who are having spontaneous breathing trials as part of their weaning protocol.

      Patients will be required to give written, informed consent.

      Exclusion criteria

      Any patient who has a leak around their tracheostomy tube when the tracheostomy cuff is
      inflated.

      Inability to understand English or cognitive impairment which impairs the patient's ability
      to follow directions.

      Protocol

      Baseline demographic information will be collected from each patient. This will include age,
      sex, height, weight, BMI, diagnosis, initial date of intubation and ICU admission, date of
      tracheostomy, date of admission to IICU, type and size of tracheostomy tube.

      Baseline measurements of respiratory strength will be made in all patients. These will
      include vital capacity (VC), maximal inspiratory pressure (MIP), and maximal expiratory
      pressure (MEP). These are standard measurements, routinely done in the IICU. All measurements
      will be done with the patient in a head up or sitting position with the tracheostomy cuff
      inflated.

      Measurement of cough strength will be done using an Air Zone Peak Expiratory Flow meter. This
      will be done with the patient in a head up or sitting position.

      With the tracheostomy cuff inflated, the peak expiratory flow meter will be attached directly
      to the tracheostomy tube. The patient will be instructed to take as big a breath as they can
      and then forcefully cough. This will be repeated four times. The first measurement will be
      discarded (learning curve). The peak expiratory flow will be recorded for the next three
      measurements. The three measurements should not deviate by more than 10%, and the best result
      will be recorded.

      With the tracheostomy cuff deflated, a one-way valve will be attached to the tracheostomy
      tube. The patient will use a mouthpiece to connect to the peak expiratory flow meter. The
      patient will be instructed to take as big a breath as they can and then forcefully cough.
      This will be repeated four times. The first measurement will be discarded (learning curve).
      The peak expiratory flow will be recorded for the next three measurements. The three
      measurements should not deviate by more than 10 %, and the best result will be recorded.

      The patients will be randomized to start with either the tracheostomy cuff inflated or
      deflated.

      At the end of the measurements, the patient will be returned to their usual care.

      The entire study should take approximately ten minutes.

      The investigators propose to study 20 consecutive adult patients in the IICU.

      Data analysis

      The best expiratory flow measurements will be averaged together with the tracheostomy cuff
      inflated and with the tracheostomy cuff deflated. The values will be compared using Student's
      T test. A p value < 0.05 will be considered significant.
    

Intervention name(s): Tracheostomy cuff inflation.; Tracheostomy cuff deflation
Intervention type(s): Other; Other
Intervention description(s): With the tracheostomy cuff inflated, the peak expiratory flow meter will be attached directly to the tracheostomy tube. The patient will be instructed to take as big a breath as they can and then forcefully cough. This will be repeated four times.; With the tracheostomy cuff deflated, a one-way valve will be attached to the tracheostomy tube. The patient will use a mouthpiece to connect to the peak expiratory flow meter. The patient will be instructed to take as big a breath as they can and then forcefully cough. This will be repeated four times
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: Tracheostomy; weaning; respiratory failure; cough strength