Nosocomial or Ventilator Associated Pneumonia - Risk Factors and Management

Introduction:

Nosocomial infections are acquired infections and a common cause of increased mortality and morbidity in hospitalized patients. Common nosocomial diseases include ventilator-associated pneumonia, catheter-associated injury, preventive strategies, and care bundles. Ventilation effectively saves lives in critical conditions and is widely used in intensive care units.

Ventilator-associated pneumonia, commonly known as VAP, is a nosocomial infection after more than 48 hours of mechanical ventilation support. Hospital-acquired and ventilator-associated pneumonia are healthcare-associated pneumonia, which remains a significant cause of mortality and morbidity despite advances in antimicrobial therapy and wide-range of preventive measures.

What Are Nosocomial Infections and Ventilator-Associated Pneumonia?

Various organisms, including fungi, viruses, bacteria, parasites, and bacterial infections, cause nosocomial infections. These can be commensals in individuals or originate from an exogenous source and spread via cross infections. These infections are often resistant to most antibiotics, at times extremely resistant to a drug or a pan drug, increasing treatment costs, antibiotic resistance, and antibiotic use. These infections are responsible for 4 % to 56 % of death caused by neonates.

Ventilator-associated infections are pneumonia that occurs after 48 to 72 hours of intubation and ventilation and is associated with progressive infiltrate chest x-ray, fever, sputum changes, and altered leukocyte count. Early ventilator pneumonia occurs in the early days of ventilation and is more likely caused by antibiotic-sensitive bacteria.

What Are the Symptoms of Nosocomial and Ventilator-Associated Pneumonia?

The individuals on mechanical ventilation are often sedated and unable to communicate. Many typical symptoms of pneumonia are either absent or cannot be obtained. The main signs and symptoms of ventilator-associated pneumonia are:

• Fever.

• Purulent sputum. (off-white, yellow or green, and opaque discharge especially indicating white blood cells)

• Low body temperature.

• Hypoxemia (low oxygen level).

• Most symptoms are similar to tracheobronchitis (a condition characterized by signs of respiratory infection without any radiographic evidence of pneumonia).

What Are the Risk Factors of Nosocomial and Ventilator-Associated Infections?

The risk factors for nosocomial infections are:

1. Individual factors such as extremes of age, acquired immunodeficiency syndrome (AIDS), immunosuppression due to cancer, and individuals who require intensive care for more than seven days due to chronic liver disease, total parenteral nutrition, abdominal surgeries, ventilation, chronic renal failure, presence of indwelling catheters, and impaired functional status.

2. Factors include hygiene of the hospital or ICU (intensive care unit), poor environmental surgery, inadequate staffing like insufficient nurse to patients ratio and waste management, inadequate equipment for patient use, and lack of infection control measures.

3. Iatrogenic factors like lack of training in infection control and ignorance regarding infection control practice.

How Is Ventilator-Associated Pneumonia Diagnosed?

The diagnosis of ventilator-associated pneumonia is a difficult task. A combination of clinical signs, radiographic, and laboratory evidence is required: The points:

• Temperature greater than 38 degrees Celsius to 36 degrees Celsius.

• Purulent secretions, increased secretions, and changes in secretions.

• White blood cells greater than 12,000 /mm3 or less than 4000 /mm3.

• Increased need for oxygen on the ventilator.

• Chest x-rays.

• Signs like rapid breathing, shortness of breath, and abnormal breathing.

There is no gold standard for getting cultures to identify the virus, bacteria, and fungus that cause pneumonia. A non-invasive strategy collects cultures from the trachea of individuals with symptoms of VAP.

How Are Nosocomial Infections and Ventilator-Associated Pneumonia Treated?

Broad-spectrum antibiotics are often administered until the specific bacterium and its sensitivities are identified when VAP is first suggested because the bacteria-generating infection is frequently unknown. Empiric antibiotics should consider both the personal risk factors for developing bacterium resistance as well as the regional distribution of resistant germs. If a person has experienced pneumonia in the past, details regarding the causing microorganisms may be available. Therefore, the choice of initial therapy will differ from hospital to hospital and depends exclusively on understanding of the local flora. Possible therapy combinations include:

• Vancomycin or Linezolid and Ciprofloxacin.

• Cefepime and Gentamicin or Amikacin.

• Vancomycin or Linezolid and Ceftazidime.

• Ureidopenicillin, like Piperacillin and Tazobactam.

• Carbapenem.

Once the responsible bacteria are identified, the treatment is often modified, and it is kept up until the symptoms go away. The present evidence appears to support the use of short-course antimicrobial therapies for individuals with VAP not brought about by nonfermenting Gram-negative bacilli.

How Is the Prognosis of Ventilator-Associated Pneumonia?

Ventilator-associated pneumonia after intubation involves a few resistant organisms and is associated with a more favorable outcome. Respiratory failure requiring mechanical ventilator support is related to determining the exact contribution of VAP to high mortality. Mortality is more likely when ventricular-associated pneumonia is associated with certain microorganisms, bloodstream infections, and ineffective initial antibiotics. Ventilator-associated pneumonia is more common in individuals with acute respiratory distress syndrome.

How Is Ventilator-Associated Pneumonia Prevented?

Prevention of ventilator-associated pneumonia limits exposure to resistant bacteria. And many strategies limit infection while intubated. Resistant bacteria are spread in many ways in infectious diseases. Preventive measures aim to reduce the risk of ventilator-associated pneumonia include strategies such as proper hand hygiene, oral care, the elevation of the head of the bed, regular assessment of the need for continued mechanical ventilation, and implementation of ventilator-associated pneumonia bundles.

• Hand washing and sterile techniques for invasive procedures and isolation of patients with known resistant organisms are mandatory for effective infection control.

• One crucial aspect is limiting the amount of sedation a ventilated person receives.

• Antiseptic mouthwashes like Chlorhexidine may also reduce the risk of ventricular-associated pneumonia. This is mainly restricted to those who have undergone cardiac surgery.

• Special tracheal tubes with an incorporated suction lumen can be used for that reason. New cuff technology-based polyurethane in combination with subglottic drainage shows significant delay in the early and late onset of ventilator-associated pneumonia.

• Silver-coated endotracheal tubes reduce the incidence of ventilator-associated pneumonia.

Conclusion:

Although ventilator-associated pneumonia has decreased in recent years due to the implementation of many therapeutic strategies, it remains one of the most common causes of nosocomial infections, which can be fatal during hospitalizations in critical care units.

Ventilator-associated pneumonia and nosocomial infections increase individuals' morbidity, ICU and hospital length of stay, treatment costs, and mortality. Increased use of antibiotics leads to antibiotic resistance and outbreaks of multidrug-resistant infections. Adhering to care bundles, receiving health education, and growing awareness effectively reduce nosocomial infections.