Cause
Risk factors
Risk factors for VAP include underlying heart or lung disease, neurologic disease, and trauma, as well as modifiable risk factors such as whether the head of the bed is flat (increased risk) or raised, whether the patient had an aspiration event before intubation, and prior antibiotic exposure. As a result of intubation many of the bodys defenses against infections are reduced or impaired; this can result in an ability for microorganisms to enter and cause infection. Patients who are in the ICU for head trauma or other severe neurologic illness, as well as patients who are in the ICU for blunt or penetrating trauma, are at especially high risk of developing VAP. Further, patients hospitalized for blunt trauma are at a higher risk of developing VAP compared to patients with penetrating trauma.Ventilator-associated tracheobronchitis may be a risk factor for VAP, though not all cases of VAT progress to VAP.Recent studies have also linked the overall oral health of a patient to the potential development of VAP; suggesting that bacteria found in plaque can "migrate to the respiratory system." Microbiology
The microbiologic flora responsible for VAP is different from that of the more common community-acquired pneumonia (CAP). In particular, viruses and fungi are uncommon causes in people who do not have underlying immune deficiencies. Though any microorganism that causes CAP can cause VAP, there are several bacteria which are particularly important causes of VAP because of their resistance to commonly used antibiotics. These bacteria are referred to as multidrug resistant (MDR).
The IPSS scoring system can help triage patients for more aggressive treatment (i.e. bone marrow transplant) as well as help determine the best timing of this therapy. Supportive care with blood products and hematopoietic growth factors (e.g. erythropoietin) is the mainstay of therapy. The regulatory environment for the use of erythropoietins is evolving, according to a recent US Medicare National coverage determination. However, no comment on the use of hematopoietic growth factors for MDS was made in that document.Agents have been approved by the U.S. Food and Drug Administration (FDA) for the treatment of MDS:

5-azacytidine: 21-month median survival
Decitabine: Complete response rate reported as high as 43%. A phase I study has shown efficacy in AML when decitabine is combined with valproic acid. Lenalidomide: Effective in reducing red blood cell transfusion requirement in patients with the chromosome 5q deletion subtype of MDS
Decitabine/cedazuridine (Inqovi) is a fixed-dosed combination medication for the treatment of adults with myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML).Chemotherapy with the hypomethylating agents 5-azacytidine and decitabine has been shown to decrease blood transfusion requirements and to retard the progression of MDS to AML. Lenalidomide was approved by the FDA in December 2005 only for use in the 5q- syndrome. In the United States, treatment of MDS with lenalidomide costs about $9,200 per month. The chemotherapy may be supported by other drugs like all-trans retinoic acid (ATRA), however the evidence of benefit is not clear.HLA-matched allogeneic stem cell transplantation, particularly in younger (i.e.