Research Paper Example on Ventilator Acquired Pneumonia

Ventilator-associated pneumonia (VAP) occurs within 48 hours or more after intubation of a patient and being given mechanical ventilation. In the U.S., pneumonia is the second common nosocomial disease in severely ill patients, and it affects about 27% of severely sick patients. 86% of nosocomial pneumonia are related to mechanical ventilation and are referred as ventilator-associated pneumonia (VAP). In the U.S., about 280,000 cases are reported every year and the mortality rate resulting from the infection range from 0 to 50%. Apart from demise, VAP has other negative economic impact such as increased stay in the ICU (4 to 13 days), and higher costs associated with the disease as it is estimated it enhances the cost of medication with about $5,000to $20,000 per diagnosis. VAP diagnosis requires high clinical suspicion together with the radiographic examination, bedside examination as well as microbiological analysis of respiratory secretions. Physicians should carry out aggressive surveillance to understand local factors that might have led to VAP and microbiologic milieu of every particular unit. It is important for the physician to adopt the use of judicious antibiotic to prevent resistant organisms that continue to attack ICUs and critically ill patients.

Etiologic Agents

Microorganisms that cause VAP vary depending on the population of the person in the ICU, the particular diagnostic method used, and the duration that a patient stays in the hospital and ICU. Most of the respiratory infections result from gram-negative bacilli (GNB). According to Koenig & Truwit (2006), about 60% of VAP is brought by aerobic GNB. However, research has shown that currently, gram-positive bacteria are increasing in the hospital and ICUs. It was confirmed by 24 studies that were conducted with ventilated patients, where their bacteriologic studies were restricted to untainted specimens. Many types of research have shown a high rate of polymicrobial infection in VAP. A study of 172 incidences of bacteremic nosocomial pneumonia, 13% of them were as a result of multiple pathogens. In a similar study, where PSB was used to test the cause of nosocomial pneumonia in 52 cases, 40% polymicrobial infection caused the disease.

Anaerobes, Legionella species, viruses, and fungi are also among the causes of VAP. However, many of these causative agents may be underreported due to the difficulties involved and the diagnostic techniques applied to identify those agents including viruses and anaerobic bacteria. A study was conducted using 130 patients to determine the frequency of anaerobes; the researchers found 23% of the total numbers of cases were as a result of anaerobes. Also, the dominant strains isolated can be categorized as follows; Fusobacterium nucleatum 17%, Prevotella melaninogenica 36%, and Veinllonella parvula 12% (Koenig & Truwit, 2006). The possibility of recovering anaerobic bacteria is high in patients who are orotracheally intubated and those who had been infected by pneumonia within the five days after ICU admission.

Diagnosis

Clinical Diagnosis

VAP is typically suspected after a person gets a new and tolerant infiltrate on the chest leukocytosis and purulent tracheobronchial secretions. Professionals know that Community-acquired pneumonia has accepted clinical criteria for determining its presence, but this is not the case in VAP where the criteria have limited diagnostic values. The low accuracy rate in diagnosing VAP is brought about by factors such purulent tracheobronchial secretions are also found in individuals who are being given prolonged mechanical ventilation which is occasionally brought by pneumonia. Some of these conditions include surgery, trauma, and deep vein thrombosis, pulmonary embolism, the fibroproliferative phase of ARDS, and pulmonary infarction. Clinical criteria used to detect VAP include new and progressive radiographic infiltrate that occur within 48 hours and two of the following: leukocyte count of more than 10,000 cells/ml, a temperature of not less than 360C and more than 380C or gas exchange degradation (Amanullah & Mosenifar, 2017). The diagnosis of nosocomial tracheobronchitis should be conducted after the presence of a positive sputum culture, purulent sputum, leukocytosis, and fever. Nosocomial tracheobronchitis is associated with a prolonged stay in the ICU and a period spent on the ventilator with no increased possibility of death. It is crucial to note differentiating tracheobronchitis from pneumonia depends on radiograph which is portable in the ICU and mostly of low quality.

Radiologic Diagnosis

The poor-quality of films reduces the accuracy of chest X-rays. VAP that cannot be detected using a standard or portable chest X-ray can be detected using computed tomography scan. Additionally, asymmetric pulmonary infiltrates can also be as a result of many noninfectious disorders like atelectasis, chemical pneumonitis, pulmonary contusion, drug reaction, and pulmonary hemorrhage. Overall, a radiograph can only detect 27% to 35% of VAP cases. But due to their high specificity, some chest radiograph results are essential in starting the diagnosis of VAP when present. These useful findings include an air bronchogram and an air space process abutting fissure. The major issue is that these kind of radiographic abnormalities are not common.

Microbiologic Diagnosis

This involves various ways of controlling or treating the disease. First, treatment of warranted in case VAP spreads to the pleural space or blood, and the organisms are known to cause pneumonia. Two sets of thoracentesis and blood cultures are recommended for nonloculated pleural effusions of more than 10mm in diameter as a way of evaluating suspected VAP. Second, semi-quantitative or nonquantitative airway sampling of tracheal secretions enjoy the benefit of reproducibility and require no specialized equipment or technique or little technical expertise. However, gram staining may not give an accurate result because upper respiratory tract is quickly (after a few hours of intubation) inhabited by pulmonary pathogens, even in the absence of pneumonia. The clinician should know that overlying on clinical diagnosis of VAP can result in undertreatment of alternative noninfectious and infectious causes of pulmonary infiltrates and fever in mechanically ventilated patients.

Lastly, a quantitative culture of airways a specimen which is used to improve the accuracy of the VAP diagnosis and avoidable antibiotic use regularly leads to many problems. There are many roles of quantitative cultures, and some include nonbronchoscopic methods like a sampling of secretions from distal airways via an endobronchial catheter. Many factors affect or influence the outcomes of quantitative cultures which includes the experience and skill of the operator, timing of pneumonia, and the adequacy of the specimen. Other factors include technical aspects like special populations like those with the chronic obstructive pulmonary ailment, proper processing and delay in transporting to the laboratory.

Treatment

Many principles should be considered when choosing the proper therapy for VAP such as knowledge of local resistance patterns within the ICU, organisms likely to be present, and rationale antibiotic regimen. Clinicians can also be able to know the sensitivities and organisms before the development of VAP but when it is treating the patient it critical for physicians to make empirical choices that offer enough coverage (Gordon, 2013). Early and efficient therapy for VAP results in reduced mortality. According to Koenig & Truwit (2006), proper empirical treatment can lower the death rate by 38%. On the other hand, delay in administering appropriate antibiotic therapy for VAP increases the chances of death. A delay in more than 24 hours increases the chance of death to occur at a rate of 67% as compared to 28% of those who are treated without delay. Caregivers can avoid any form of delay; critically ill patients should be treated continually with antibiotics as other noninfectious and infectious ailments are being pursued. It is important to direct antibiotics diagnostic efforts at non-VAP that leads to sepsis. VAP can be effectively treated using various strategies.

Firstly, qualitative culture approach is preferred in the management of suspected VAP. Quantitative has superior specificity compared to semi-quantitative and non-quantitative culture techniques. Qualitative culture allows physicians to discontinue antibiotics to avoid attendant complications such as a potential increase in bacterial resistance. When applying quantitative culture strategy, it is crucial to interpreting outcomes in clinical context. Secondly, clinical strategy and its principal advantage are that when diagnosing VAP it does not require specialized equipment, technique or expertise (Kalanuria, Zai & Mirski, 2017). However, this strategy has a low specificity of clinical symptoms and signs of VAP hence it can lead to treatment of noninfectious processes using broad-spectrum antibiotics. Additionally, a physician might fail to notice and track noninfectious mimics of non-pulmonary and VAP infections. Lastly, managing antibiotic involves patients who are at a risk of VAP resulting from multidrug-resistant organisms and others who are not of such dangers. Risk factors that might result in multidrug-resistant organisms are an antimicrobial therapy that may have been administered in the previous 90 days, immunosuppressive disease, resistance in the local hospital unit or community, and current hospitalization exceeding five days. When there are no risk factors associated with multidrug-resistant bacteria, physicians should select an empirical therapy for Haemophilus influenza, Streptococcus pneumoniae and Staphylococcus aureus. In case risk factors linked to multidrug-resistant bacteria are present, the physician should also consider the above organisms as well as Enterobacter, Pseudomonas aeruginosa, Klebsiella, Burkholderia cepacia, and Stenotrophomonas maltophilia (Koenig & Truwit, 2006).

Prevention

Physicians should focus on minimizing or eliminating the occurrence of VAP for better outcomes in patients. These involve simple measures such as ensuring health care team complies with the ICU requirements. They should focus addressing modifiable risk factors like nasogastric tubes, endotracheal, enteral nutrition, tracheotomy, corticosteroid administration, gastric pH-modifying agents, and medications (Waters & Muscedere, 2015).

In case, the conditions of the patients start to deteriorates while in the ICU, VAP should be suspected. After suspicion of VAP administration of antibiotic should begin on time, and the quantitative cultures that are obtained should be wide in coverage. Physicians should be guided by the knowledge of local antibiograms and likelihood of organisms when choosing antibiotics. In case the patient was taking antibiotic at the time when VAP is suspected, antibiotics from a different category should be selected. After taking the patient to the ICU, an assessment should be conducted on day 3 to find out the likelihood of VAP. Assessments performed include stoppage of antibiotics and a repeat of CPIS. Caregivers should implement simple and efficient measure to avert the occurrence of VAP at a minimum cost. These measures are constant respiratory care, NIV, elevation of the head, hand hygiene, and minimization of sedation.

References

Amanullah, S., & Mosenifar, Z. (2017). Ventilator-Associated Pneumonia: Overview of Nosocomial Pneumonias, Epidemiology of VAP, Clinical Presentation of VAP. Emedicine.medscape.com.

Gordon, S. (2013). HospitalAcquired, Health CareAssociated, and VentilatorAssociated Pneumonia. Clevelandclinicmeded.com. Retrieved 12 July 2017, from...