Ventilator Associated Harms (VAH): The Basics

Mechanical ventilation is necessary in a variety of clinical scenarios and carries with it numerous risks. Patients who develop a ventilator-associated harm have worse outcomes compared to other patients including significantly increased mortality. Fortunately, many of these are completely preventable with a few simple interventions, commonly referred to as a ‘ventilator bundle.’

Risks of Mechanical Ventilation

Unfortunately, mechanical ventilation is a necessity in some clinical scenarios and no medical intervention is without risk.

The risks of mechanical ventilation include:

  • Ventilator-associated pneumonia (VAP)
  • Ventilator-associated lung injury
  • Venous thromboembolism
  • Development of a stress ulcer
  • Deconditioning and weakness

While all patients are at risk for developing complications related to mechanical ventilation, certain conditions increase the risk for this occurring. The risk is greater for those patients with:

  • Impaired immune systems
  • Advanced age
  • Poor nutritional status
  • Atypical body habitus
  • Those in whom oral care is not possible
  • Those requiring prolonged ventilation

A Closer Look at the Elements of the Bundle…

Elevating the Head of the Bed

Ventilator-associated pneumonia (VAP) is thought to result, in part, from the aspiration of bacteria contained in secretions which pool in the oropharynx. By raising the head of the bed into a semi-upright position, studies have shown up to a 75% reduction in the risk of developing a VAP. This simple method is very effective and should be employed whenever possible.

Oral Care

Because of the influence of oral bacteria in the development of VAP, decontamination with an oral chlorhexidine solution is thought to help reduce the risk of developing pneumonia. Commonly, 0.12% chlorhexidine is used in the form of an oral swab and this should be completed every four hours in patients requiring mechanical ventilation.

Learn more about the use of oral decontamination to reduce the risk of VAP »

Daily spontaneous awakening trials and spontaneous breathing trials (SAT and SBT)

Decades of medical research has attempted to answer the question of which medications are most effective at providing sedation for mechanical ventilation during critical illness and when it may be safe and appropriate to wean a patient from the ventilator. While these medications are sometimes necessary, minimizing the dose may reduce the unwanted side effects of delirium, delayed awakening, and prolonged ICU stays.

Given the complicated impact that critical illness can have on these issues, and the tremendous variability patients may have in response to these medications, the critical care literature supports the use of protocols for daily sedation interruption (spontaneous awakening trials or SATs) paired together with spontaneous breathing trials (SBTs) to minimize the dose of sedative medications and to most effectively determine the readiness of patients for extubation.

When the combination of spontaneous breathing trials and sedation interruption protocols were applied to large populations of critical care patients, the group of patients receiving these interventions required fewer days of mechanical ventilation, had shorter ICU stays, and demonstrated statistically higher 180-day and 1-year survival rates.  Learn more »

By implementing these simple protocols, outcomes can be substantially improved.

Stress Ulcer Prophylaxis

Stress-related mucosal disease (SRMD) occurs in as many of 75-100% of ICU patients. Fortunately, the incidence of clinically significant bleeding is quite low (<6%). However, patients who develop significant gastrointestinal bleeding in the ICU have a significantly higher mortality rate so it is critical that measures be taken to prevent this.

SRMD is thought to occur from a combination of splanchnic hypoperfusion resulting in decreased gastric motility leading to prolonged exposure of the mucosa to acid secretions. Acid suppressive therapy is therefore a mainstay of therapy for its prevention.  Learn more about the pathophysiology of SRMD.

Acid suppression with both H2-antagonists (H2RAs) and proton pump inhibitors (PPIs) has been proven to be effective in decreasing the incidence of clinically significant bleeding. However, acid suppression has also been found to be associated with increased risk for developing infection with C. difficile and an increased risk of developing pneumonia.

Therefore, it is recommended that these agents be used only in patients at high-risk of developing clinically important bleeding. Most patients will do well with either an H2RA or PPI but some should receive a PPI due to their underlying condition.

Major Risk Factors Include:

  • Mechanical Ventilation > 48 hours
  • Coagulopathy
  • Severe traumatic brain injury
  • Trauma (with Injury Severity Score > 16)
  • Spinal cord injury
  • Extensive burns
  • Transplant recipients (consider PPI)
  • Patients on dual anti-platelet therapy or anticoagulation (PPI)
  • Recent GI bleed (within last year, PPI)
  • Septic shock (relative indication)
  • High-dose steroid therapy (relative indication)

Stress ulcer prophylaxis is a complex issue and while guidelines exist from numerous professional organizations, decisions regarding individual treatment must be made by the responsible provider.

Venous Thromboembolism Prophylaxis

Due to the immobilization often associated with critical illness requiring mechanical ventilation, patients are at risk for developing venous thromboembolism. Prophylaxis, either mechanical or pharmacologic, should be considered in all patients.  Learn more »

Hand Hygiene

Something as simple as hand washing can have a big impact. In fact, some studies have shown that simply instituting a hand hygiene program reduced the incidence of ventilator-associated pneumonia in the ICU. Whether alcohol-based gels or more traditional soap-and-water are used, anyone entering or leaving a patient’s room should practice good hand hygiene.

Subglottic suctioning

Given the role the oral secretions play in the development of VAP, it is important to recognize that some secretions tend to accumulate above the cuff of the endotracheal tube. Using endotracheal tubes designed to allow for drainage of these subglottic secretions has been shown in some studies to decrease risk for developing VAP, ICU length of stay, and duration of mechanical ventilation as well as delaying the time to development of VAP in some patients.

The benefit from subglottic secretion drainage is most pronounced for longer periods of mechanical ventilation. For this reason, subglottic secretion drainage endotracheal tubes may be considered in adult patients requiring oral intubation in whom prolonged periods of mechanical ventilation may be employed. Patients with a history of requiring prolonged mechanical ventilation, those with increased levels of oral secretions, oropharyngeal bleeding, or active gastrointestinal reflux disease may receive particular benefit.

These endotracheal tubes may not be appropriate for all patients, however, given their increased diameter. Patients with known or suspected tracheomalacia or subglottic stenosis may not be candidates for subglottic suctioining endotracheal tubes.

Early Mobilization

Mobilization has many benefits in the ICU including decreasing delirium, maintaining strength, and decreasing the use of sedatives. Even patients who require mechanical ventilation should participate in an early mobilization program, aiming to begin mobility within 48 hours of ICU admission.

Mobilization has been shown to promote airway clearance, maintain strength, facilitate weaning from the ventilator, and patients who participate in an early mobilization program have been shown to have more ventilator-free days.

While it can be challenging to coordinate and manage the many lines and monitors which critically-ill patients require, the benefits of mobility and ambulation are substantial and this therapy can be accomplished safely in the ICU.

Learn more about how sub-glottic suctioning may reduce the incidence of VAP.

Learn more about the importance of Early Mobilization.

Next: Preventing VTE

Preventing Venous Thromboembolism.

Learn more