Reduced Ventilator-Free Days and Bacterial Colonization of Sub-Glottic Secretions

All patients secrete fluids into the upper airway from the base of our tongue and other
related structures. These "subglottic" secretions are normally cleared by swallowing, but
when a person requires mechanical ventilation that process is blocked by the breathing tube
and the subglottic secretions tend to accumulate. The removal of these subglottic secretions
is very important because bacteria that normally inhabit the back of our throats can enter
and ultimately colonize collected pools of subglottic secretions. This process is called
"micro-aspiration" and has been shown to be strong risk factor for the development of
Ventilator associated pneumonia (VAP). Previously, doctors and nurses would attempt to limit
these secretions by passing small suction tubes through the breathing tube, but this was
found to be ineffective and increased the risk for bleeding and lung injury.

A new development in the management of patients requiring mechanical ventilation is the
Hi-Lo endotracheal tube. This device has "suction ports" on either side of the tube that
allow for the removal of accumulated subglottic secretions.The standard of care is to use
this Hi-Lo ET tube and to remove subglottic secretions every 4-6 hours. The Hi-Lo tube is
designed to minimize any suction related trauma. Moreover, recent studies of this ET tube
have shown that regular suctioning reduces the incidence of VAP. When these "colonized"
secretions were treated with antibiotics, it reduced the number of VAP and shortened the
time on the breathing machine. The observation that treatment of bacterial colonization of
subglottic secretions reduced the time on the breathing machine is potentially very
important clinically. In this study, we propose that the development of bacterial
colonization directly contributes to respiratory failure and leads to longer times on the
ventilator. The primary aim of the study could lead to reduce the time that patients need
mechanical ventilation.

Recent studies have identified a group of "protective proteins" called the heat shock
proteins (HSP) that appear to protect patients from developing pneumonia. The protective
effect of these proteins is even more pronounced in patients that require mechanical
ventilation. Under stressed conditions, HSPs are secreted or released into the subglottic
secretions and the level of secretion is sufficient appears to prevent bacteria from
"colonizing" the upper respiratory tract.

In addition to looking at rates of bacterial colonization of these secretions, a portion of
these secretions to measure the amount of HSP and whether reduced secretion leads to
prolonged time on the ventilator.

Inclusion Criteria:

1. Age > 18 years of age

2. Patients requiring mechanical ventilation for altered mental status, drug overdose or
any condition that airway protection from aspiration is clinically warranted

3. Patients requiring mechanical ventilation following Cardiothoracic bypass or valve
replacement surgery

4. Patients requiring mechanical ventilation for stroke, intra-cranial bleed, sub-dural
hematoma, meningitis or closed head injury

5. Patients requiring mechanical ventilation for following of abdominal surgery in which
there were no discernable infiltrates on chest X-ray

6. Patients requiring mechanical ventilation for primary lung disease (COPD, emphysema
etc.) if no discernable infiltrates on chest X-ray.

Exclusion Criteria:

- 1) Patients receiving mechanical ventilation for greater than 6 hrs at the time of
enrollment.

2) Patients requiring mechanical ventilation for ARDS, pneumonia or traumatic lung
injury.

3) Patients receiving more than one dose of any antibiotic.

4) Patients undergoing surgical resection for lung cancer or any other surgery
directly involving lung parenchyma