Klompas M et al. Strategies for triage and treatment. Healthcare Acquired Pneumonia Including Ventilator Associated Pneumonia Thoracic Key Cleve Clin J Med. . In agreement with the recent hospital-acquired pneumonia and ventilator-associated pneumonia. No clear definition but clinical improvement should generally be seen within 3 days. Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia. Validated definition includes either one major criterion or three or more minor criteria Minor criteria. 2007 Infectious Diseases Society of AmericaAmerican Thoracic Society Criteria for Defining Severe Community-acquired Pneumonia.