Ventilator Associated Pneumonia

Introduction

According to the CDC, “Ventilator-associated pneumonia (VAP) is a lung infection that develops in a person using a ventilator.” A ventilator machine is used to help a patient breathe by giving oxygen through a tube; it is placed in patient’s mouth or nose, or through a hole in front of the neck. An infection may occur when germs reach the patient’s lungs through the tube.

Definition

Ventilator-associated pneumonia is a type of lung infection that occurs in people who are on mechanical ventilation breathing machines in hospitals. As such, ventilator-associated pneumonia typically affects critically ill patients who are in an intensive care unit (ICU). Ventilator-associated pneumonia is a major source of increased illness and death.

Incidence

•  Ventilator-associated pneumonia is one of the top three infection concerns in the healthcare environment. 
• Ventilator-associated pneumonia may account for up to 60% of all the deaths from healthcare associated infections. 
• Ventilator-associated pneumonia affects up to 28% of ventilated patients.
• Health care associated pneumonia patients have a mortality rate of up to 33%. 
• Ventilator-associated pneumonia increases length of stay in the intensive care unit (ICU) by four to six days. 

Anatomy and physiology

The lungs are pyramid-shaped, paired organs. They are connected to the trachea (commonly known as wind wipe) by the right and left bronchi on the inferior surface.  

The lungs are bordered by the diaphragm. The diaphragm is the flat, dome-shaped muscle located at the base of the lungs and thoracic cavity.

The functional unit of the lungs includes the respiratory bronchioles, alveolar ducts, and sacs and the alveoli The air passage ways of the lungs become smaller, the structure of their walls changes.

The major physiological function of the respiratory system is to supply the body with oxygen and to dispose carbon dioxide.

•   Pulmonary ventilation - Air must move into and out of the lungs so that gases in the air sacs are continuously refreshed, and this process is commonly called breathing. 
•  External respiration - Exchange of gases between the pulmonary blood and alveoli must take place. 
•  Respiratory gas transport - Oxygen and carbon dioxide must be transported to and from the lungs and tissue cells of the body via the bloodstream. 
•  Internal respiration - At systemic capillaries, gas exchanges must occur between the blood and tissue cells. 

Causes/ Risk factors

It commonly affects individuals aged 65 years and above

•   Being hospitalized - If the patient is admitted in an intensive care unit, especially if put on a machine that helps to breathe (a ventilator). 
•  Smoking - Smoking damages body’s natural defenses against the bacteria and viruses that cause pneumonia. 
•  Weakened or suppressed immune system- People with history of organ transplant, those on chemotherapy or long-term steroids and HIV positive patients 
•  Bacterial cause - Streptococcus 

Signs and symptoms of pneumonia may include:

The sign and symptoms are chest pain when patient breathes or coughs, confusion or changes in mental awareness (in adults aged 65 years and older), cough, fatigue, fever, sweating, chills, lower than normal body temperature (in adults older than 65 years and people with weak immune systems), and other symptoms like nausea, vomiting or diarrhoea.

In these cases, detailed history, physical examination, and investigations such as chest x-ray, CT scan, sputum culture and complete blood count are required.

Complications

Even with treatment, some people with pneumonia, especially those in high-risk groups, may experience complications such as:  

•   Bacteria in the bloodstream (bacteremia): Bacteria that enter the bloodstream from lungs can spread the infection to other organs, potentially causing organ failure. 
•  Difficulty in breathing: If cases with severe pneumonia or in patients with chronic underlying lung diseases, difficulty in breathing can be observed. Such cases may need hospitalization and assistance of ventilator for breathing while the lung heals. 
•  Fluid accumulation around the lungs (pleural effusion): Pneumonia may cause fluid to build up in the thin space between layers of tissues that line the lungs and chest cavity (pleura). If the fluid becomes infected, it requires drainage through a chest tube or removal with surgery. 
•  Lung abscess: An abscess occurs if pus is formed in a cavity in the lung. This is usually treated with antibiotics. Sometimes, surgery or drainage with a long needle or tube placed into the abscess is needed for removal of the pus.

VAP Prevention Strategies

• Elevate patient’s head by 30 to 45 degrees. 
•  Maintain good oral hygiene to prevent dental caries and gum or tongue infection. 
•  Wean ICU patients from the ventilator more quickly by using a percussion vest. 
•  Assess patient readiness to extubate daily. 
•  Perform hand hygiene before and after patient contact, before aseptic procedures, when in contact with the care environment or body fluids regardless of glove use. 
•  Follow standard precaution guidelines to avoid nosocomial infection in the ICU. 
•  Minimize saline lavage. 
•  Use a closed-suction system or sterile single-use suction catheter to prevent the infection. 
•  Prevent patient contamination from ventilator circuit condensate as there is a possibility for spreading infection. 
•  Maintain optimal pressure in the endotracheal tube (EDT) cuff while patient is intubated. 
•  Avoid unnecessary manipulation of EDT. 
•  Vaccinate the staff and patients against influenza. 
•  Utilize methods for early diagnosis of VAP for prompt treatment. 
•  Provide continuing education for the staff members and health education to the patient and his/her family members regarding VAP. 

There are various VAP prevention strategies that are to be followed mainly by respiratory therapy staff, but as the members of a multi-disciplinary care team, nurses should also be aware of these. These prevention strategies are outlined below.

•   Use a CASS Tube – A key concern is that secretions accumulate above the cuff in the endotracheal tube and since the tube prevents the glottis from closing, these secretions can be aspirated or can leak into the lungs. Suctioning them is difficult because they can’t be reached through typical oral suctioning methods, so the CDC recommends a device known as a CASS tube, which provides constant suction of oral secretions. Research indicates that this device greatly lowers the chances of VAP. 
•  Use Orotracheal Intubation if Possible – CDC guidelines also recommend using orotracheal rather than naso tracheal intubation, unless contraindicated. Nasal tubes can cause sinus infections, which can result in pathogens reaching the lower respiratory tract. 
•  Avoid PPIs when Possible – Some studies suggest that proton pump inhibitors (PPI) (Prevacid, Prilosec), which are commonly prescribed to prevent stress ulcers and gastritis in ICU patients, may increase the risk of VAP by changing the acidity of the aero digestive tract and making it more susceptible to bacterial colonization. Joint recommendations issued by SHEA and IDSA suggest avoiding PPIs whenever possible, but indicate that the preferential use of sucralfate (brand name Carafate) instead of PPIs is considered by the CDC to be an unresolved issue.
•  Lighten Sedation at Regular Intervals – The joint SHEA/IDSA guidelines also recommend a protocol to lighten sedation at regular intervals, in order to assess for neurological readiness to wean the patient from ventilation. (For ICU nurses, this will require increased monitoring and vigilance, as lightly sedated patients may be at increased risk of pain, anxiety, or attempts to self-extubate.) A randomized trial of 128 ventilated patients demonstrated that daily interruption of sedation resulted in a significant reduction of time on ventilation, decreasing the duration from 7.3 days to 4.9 days.

Nurses responsibilities

•   Provide visual and hearing aids during daytime. 
•  Encourage communication and reorient the patient frequently.

               a. Ensure that room calendar is up-to-date.

               b. Introduce oneself with each encounter, providing the current date and time and explaining what will be done, and giving the patient choices regarding his or her care whenever possible.

• Have the family bring in a few familiar objects from home to display in the patient’s room. 
•  Ask the patient/family if they watch television, and, if so, what shows they prefer. Provide the patient with these choices, as well as with daily news on TV or radio. 
•  Provide non-verbal music or opt for the patient’s preference. 
•  Open shades and keep lights on during the day. 
•  Provide an uninterrupted rest period in the afternoons between 1-3 pm. 
•  Minimize use of physical restraints (including lines and tubes).

          a. Provide early and progressive mobility

Nighttime - PM Care (begin between 2100-2200)

•   Ask the patient if toileting is needed (bedpan, bathroom, bedside commode, etc). 
•  Perform oral care (toothbrush, mouth moisture, with assistance or independently), assist the patient in washing his face and hands, perform back care or massage with warmed lotion, offer earplugs. 
•  Ask “Do you take or do anything at home to help you sleep? Do you sleep with white noise (fan, TV, music)?” 
•  Ensure the call light is within reach and the bed is in the low position. Close the shades, dim the lights, close the door (except in the MICU), put the bedside charts outside of the room, and put the “sleep cycle in progress” sign on the door and minimize noise inside and outside of the room. 
•  Allow for minimum of two hours of uninterrupted sleep, allowing for a full 90-minute sleep cycle. Remove the automatic BP cuff, enter the room with a flashlight or low lighting to perform necessary activities.

           a. If patient has been hemo dynamically stable in the previous 24 hours, explore extending the uninterrupted sleep period to four hours (but only for patients who are unrestrained and can turn themselves)

Conclusion

The ventilator associated pneumonia is a hospital acquired infection, spread by the bacteria. The causes of the ventilator associated pneumonia, its anatomy and physiology, signs and symptoms are low oxygen levels, shortness of breath and pus or sputum secretion. The preferred treatment option is administration of broad spectrum antibiotics and the preventive measures includes elevation of patient’s head by 30 to 45 degrees, maintenance of good oral hygiene for reducing the dental caries and gum or tongue infection, weaning ICU patients from the ventilator more quickly by using a percussion vest, assessing patient readiness to extubate daily, performing hand hygiene before and after patient contact, before aseptic procedures, when in contact with the care environment or body fluids regardless of glove use.