Ventilator Associated Pneumonia in Taper Guard Versus Normal Tube in ICU Patients

Comparison of the Incidence of Ventilator Associated Pneumonia in Patients Intubated With the Taper Guard Endotracheal Tube Versus a Normal Endotracheal Tube

Ventilator associated pneumonia ( VAP) adds burden to the care of the intensive care patients as they may cause the death of the patient or prolong the intensive care stay or complicate the illness in other ways. The risk of infection is dependent on the interplay between bacteria load into the lungs and the immune status. There has been a lot of focus on bacteria load reduction and this includes the use of subglottic suctioning in an attempt to reduce the amount of bacteria that may move into the lungs. The Hi Lo tubes which were designed to allow subglottic suctioning was significantly effective in reducing the incidence of ventilator associated pneumonia compared to normal tubes. A new generation of endotracheal tubes that not only incorporate subglottic suctioning but provide a more snug fit into the tracheal by a new tapering design may be even more useful to provide the solution for bacterial load reduction. Conventional tubes which may furrow on themselves to allow the creation of microchannels may aid microaspiration. The taper guard which has facilities for subglottic suctioning as well as the strategy to reduce furrowing to the minimum may be the answer to the problem of ventilator associated pneumonia. This study is to determine the extent of protection this tube has against ventilator associated pneumonia compared with conventional endotracheal tubes

Methodology This will be a prospective randomized trial with 2 treatment groups with 100 patients in each arm. The control group ( Group C) will be intubated with our conventional endotracheal tubes and the test group ( Group T) will be intubated with the special Taper guard tubes with subglottic suctioning and snug fit facilities.

All adult patients ( > 18 years of age) admitted into the Intensive Care Unit who are likely to receive more than 72 hours of ventilation will be admitted into the trial. The trial has been cleared by the Hospital Ethics and informed consent will be obtained from the patient's next of kin.

All patients will have their demographic data collected, the primary reason for ICU admission, the APACHE 2 scores, presence of infection at admission, antibiotic use and whether they have risk factors for VAP ( previous surgery, trauma, antibiotics usage, reflux disease and use of stress ulcer prophylaxis, decreased immune status ) The following guidelines modified from the American Thoracic Society 2005 will be used as the basis for diagnosing Ventilator Associated Pneumonia.

Guideline for Diagnosis of Ventilator Associated Pneumonia (VAP)2

1. Patient ventilated for more than 48 hours.

2. Suspicion of ventilation associated pneumonia

3. Presence of a new or progressive infiltrate on chest radiograph.

4. At least 2 of the following:

   1. Fever, defined as an oral temperature greater than 38 degree C, a tympanic temperature greater than 38.5 degree C or a rectal /core temperature greater than 39 degree C OR hypothermia, defined as a rectal/core body temperature of less than 35 degree C.
   2. Elevated total peripheral WBC count (greater than 12000/mm3) or greater than 15% bands regardless of total peripheral WBC count; or leucopenia with total peripheral WBC less than 4500/mm3 (caused by the infection)
   3. New onset of purulent sputum production or other respiratory secretions (e.g. tracheal secretions), or a change in the character of sputum or tracheal secretions
   4. Worsening hypoxaemia with reduction in PaO2/ FiO2 greater or equal to 15%

In addition all patients will have aspirants from the oral cavity (control group) or subglottic region (group T) and the lungs ( both group C and group T) sent on alternate days for bacterial culture. All tubes will be inflated to a sealing pressure of no leak or up to 20-25 cm H2O whichever is the lower.

The sample size has been estimated based on the incidence of ventilation-associated pneumonia (VAP) which is the primary outcome measure from other studies1,2. Based on a VAP incidence of 20% and 6% in each group, 1:1 ratio, 80% power and significance value of 0.05, the number required in each group will be 89. Adding 10% for loss to follow-up, the number needed in each group will be 100 giving a total of 200 The assignment of each patient to the study will be randomized according to computer generated random numbers by the statistician who will not be a party in the ongoing clinical part of the research. In addition she will provide the allocation sequencing via an opaque envelope when a suitable patient has been identified for the assignment of the patient to the 2 groups when informed consent has been obtained. The person who intubates the patient with the endotracheal tube will use the tube that has been allocated according to the written instruction inside the now opened opaque envelope.

Patient and the clinical researchers managing the patient cannot be blinded as there are obvious differences between the 2 types of endotracheal tubes. However the assessor that will determine the presence or absence of the soft signs of ventilator associated pneumonia will be blinded to the type of tubes used. The Radiologist who reads the Chest Xrays will not be privy to the type of tubes used and the Microbiologist determining the significance of the bacteria identified in the oral/subglottic secretions and the tracheal secretions will not be aware of the endotracheal tubes used.

The main outcome measure will be the incidence of ventilator associated pneumonia on each day the patient is ventilated. The secondary outcomes will be the length of ventilation, the duration of intensive care stay, the duration of hospital stay (pre-intensive care, post-intensive care) and the incidence of mortality of the 2 groups.

Statistics Categorical variables will be analysed using Chi square test while continuous variables will be analysed using ANOVA. Intention to treat analysis will be used. Analysis will be carried out using the SPSS version 15.0 software. All statistical tests will be carried out using a significance level of 0.05.

Inclusion Criteria:

• All adult patients above 18 years old admitted into the Intensive Care unit and who is to be intubated and likely to receive more than 72 hours of ventilation would be admitted into the trial

Exclusion Criteria:

• presence of cavitary lung disease based on chest x-ray findings,
• primary lung cancer or another metastatic malignancy to the lungs, or known or suspected viral or fungal etiology,
• pneumocystis carinii pneumonia,
• legionella OR Mycoplasma pneumonia or active tuberculosis.