Ventilators are life-saving machines that can help deliver much-needed oxygen to patients who have just undergone surgery or are otherwise seriously ill. However, these machines can cause complications in some cases, most specifically a condition called ventilator-associated pneumonia that can cause additional complications.
What is Ventilator-Associated Pneumonia?
Ventilator-associated pneumonia (VAP) is pneumonia that occurs 48 to 72 hours following endotracheal intubation to assist a patient with breathing. VAP symptoms include system infection characterized by fever, altered white blood cell count, and changes in sputum. Chest x-rays can also confirm the diagnosis. VAP causes about half of all pneumonia cases acquired in a hospital and is often present in hospital intensive care units (ICU).
What Causes Ventilator-Associated Pneumonia?
VAP results from several factors working together, the most important of which is the presence of the ventilator’s endotracheal tube, which prevents a patient from a natural defense mechanism, namely the cough reflex that helps expel bacteria. As a result, bacteria can gain direct access to the lower respiratory tract, often occurring during the act of intubation. Sometimes bacteria develop as a film on the inside of the endotracheal tube or collect in other areas such as the sinuses, nasopharynx, and oropharynx, or stomach. The pressure caused by the ventilator causes the bacteria to spread throughout the lungs. Bacteria that cause early-onset VAP include Streptococcus pneumoniae, Hemophilus influenzae, methicillin-sensitive Staphylococcus aureus (MSSA), antibiotic-sensitive enteric Gram-negative bacilli, Escherichia coli, Klebsiella pneumonia, Enterobacter species, Proteus species, and Serratia marcescens. That sure seems like a lot, but a lot of bacteria out there can cause havoc. In addition to the presence of an endotracheal tube and bacteria, risk factors and immunity also determine whether a patient will develop VAP.
Bacteria causing later-onset VAP include methicillin-resistant S.aureus (MRSA), Acinetobacter, Pseudomonas aeruginosa, and extended-spectrum beta-lactamase-producing bacteria. Several other bacteria species found in the lungs can cause VAP, especially in immunocompromised patients. Ask your internist about which other bacteria may be involved.
How Common is Ventilator-Associated Pneumonia?
VAP is one of the most common infections acquired in ICUs, second only to those caused by urinary catheters. It occurs in approximately 9% to 24% of patients intubated for more than 48 hours. Mortality rates for patients who develop VAP are 45% and are the most fatal of hospital-acquired infections. The National Institutes of Health estimates that 86% of hospital-acquired pneumonia is VAP, with approximately 250,000 to 300,000 cases occurring annually.
In addition to the primary risk factor of intubation, patients who have lung diseases like COPD, asthma, and emphysema, feeding via nasogastric tube and having caregivers who are lax with handwashing and other infection control protocols.
Additional risk factors include:
- Weakened immune system
- Conditions affecting the nervous system
- Long-term antibiotic use
- Tube place through a hole in the throat instead of through the nose or mouth
- Prolonged ventilation
- Continuous sedation
- Prolonged supine position
- Older age
Ventilator-Associated Pneumonia Symptoms
- Thick mucus, sometimes green or pus-filled phlegm
- Nausea or vomiting
- Blueish nails or lips
- Low oxygen levels in the blood
To properly diagnose VAP, your doctor will review symptoms and past health and conduct an exam. Possible tests to confirm the diagnosis include:
- Blood tests to measure levels of oxygen-carbon dioxide and acid
- Blood cultures to determine what bacteria are involved
- Cultures from below the chest tube
- CT scan
- Chest x-ray to show where fluid or inflammation is in the lungs
How Ventilator-Assisted Pneumonia is Treated
Despite effective treatments, the mortality rate for patients with VAP is high. However, pneumonia itself is not always the cause of death. Instead, underlying comorbidities are often responsible. The efficacy of the initial anti-microbial treatment frequently determines the patient’s prognosis. Infection with antibiotic-resistant bacteria worsens the prognosis.
Treatment with antibiotics often begins before a formal diagnosis occurs. The antibiotic selected depends on the patient’s sensitivity and risk factors for various antibiotic-resistant pathogens. The latest recommendation from the Infectious Diseases Society of American and the American Thoracic Society recommend treating VAP patients with a narrower spectrum of antibiotics whenever possible. In institutions where infection rates are low typical treatment includes one of the following antibiotics:
When MRSA rates are higher, vancomycin or linezolid generally becomes part of the treatment, while patients who have a high mortality risk or have higher risk factors for antibiotic-resistant organisms often receive triple antibiotic therapy. Additional drugs used in such cases include:
To minimize the spread of drug-resistant bacteria, initial treatment sometimes begins with broad-spectrum drugs, then switching to narrow regimens based on the patient’s response to treatment, antibiotic susceptibility testing, and the results of cultures. Treatment may also involve oxygen therapy to improve oxygen levels throughout the body.
For uncomplicated VAP cases, the usual course of antibiotic treatment is seven days as longer courses do not reduce rates of recurrent pneumonia, duration of mechanical ventilation, length of hospital stay, or mortality. When a patient has pulmonary or extrapulmonary complications, longer courses of antibiotics are typical, with up to two weeks of drug therapy required for Pseudomonas or Acinetobacter species.
How to Prevent Ventilator-Associated Pneumonia
Even if a patient needs intubation, caregivers and home care nurses can implement many different strategies and practices to lessen the chances of VAP occurring. The care teams can implement these practices:
- Elevate the patients’ head at an angle of 30 to 45 degrees
- Thoroughly wash hands before and after touching a ventilator
- Regularly clean the inside of the patient’s mouth, including regular use of an antiseptic solution
- Only use a ventilator when necessary
- Minimize sedation
- Regularly remove fluids out of the airway
Aspiration of patient secretions, keeping equipment clean, and propping up patients in bed can go a long way toward maintaining the health of those on ventilators. The CDC also recommends using positive-pressure ventilation via a face or nose mask combined with proactive surveillance of the ventilated patient. For some patients, a continuous airway pressure (CPAP) or a bilevel positive airway pressure (BPAP) machine effectively provides sufficient oxygen and eliminates the need for intubation.
Keeping the patient propped at the proper angle can reduce the occurrence of VAP by up to 67 percent during the first 24 hours of intubation. Several observational or randomized studies confirm that patient position can affect the incidence of VAP. That’s not the only way to help reduce it. Other strategies involve techniques and monitoring by respiratory therapists. Nevertheless, you should be aware of what can be done. These include:
- Using a CASS Tube. This device provides constant suction of oral secretions that accumulate above the cuff on an endotracheal tube, which can greatly lower the chance of VAP
- Use orotracheal intubation if possible. Intubating through the nose can cause sinus infections, resulting in pathogens reaching the lower respiratory tract. Orogracheal intubation, which occurs through the mouth, lowers the chance
- Avoid Proton Pump Inhibitors (PPIs) when possible. Medications such as Prevacid and Prilosec may increase the risk of VAP by chancing the acidity of the aerodigestive tract, thereby making it susceptible to bacteria.
- Regularly lighten sedation. Joint SHEA/IDSA guidelines recommend lightening sedation regularly to assess the patient’s readiness for weaning from the ventilator. This practice also appears to reduce the patient’s time on the ventilator significantly.
- Clean the ventilator twice daily
- Give medications that keep a patient comfortable and reduce the risk of contracting VAP
Are Home Healthcare Patients at Risk for Ventilator-Associated Pneumonia?
Some chronically ill patients need intubation from time to time in a home healthcare setting. Home healthcare settings usually encounter the same organisms responsible for VAP as in hospital settings, yet the incidence and mortality are lower when patients are cared for at home. Caregivers should focus on reducing ventilator-associated pneumonia who are new to receiving mechanical ventilation at home or require ventilation for longer daily durations. These patients often have a tracheostomy, a surgical hole cut into the front of the neck that goes into the windpipe or trachea for placement of a tracheostomy tube. Patients with various conditions can live at home with a tracheostomy and premature infants who require ventilation. However, at the same time, these patients require specialized care from trained medical professionals.
How Centric Healthcare Can Help
Your loved one does not have to remain in the hospital or an extended care facility if they have periodic breathing issues that require intubation. Centric Healthcare has a variety of medical professionals that include private duty nurses and others who can manage your loved one’s health. We have staff available for 24-hour care for many different patients, including pre-term newborns and pediatric patients with unique problems. If you live in the Minneapolis, St. Paul, or Rochester areas, contact us for an evaluation and to learn about the different types of care we can provide to meet your home healthcare needs.