Written and maintained by CASRAI Editorial Board
Last updated
Short answer
Ventilator-acquired pneumonia, more often written ventilator-associated pneumonia (VAP), is pneumonia that develops in a patient who is receiving mechanical ventilation. The 2016 IDSA/ATS guideline treats it as a separate group from hospital-acquired pneumonia (HAP), which it defines as pneumonia not associated with mechanical ventilation. Hospitals now track it mainly through the broader surveillance category of ventilator-associated events, and prevention is organized around a set of hospital-wide practices.
Definition and scope
The IDSA/ATS guideline (Kalil et al., Clinical Infectious Diseases 2016;63(5):575-582) describes HAP as “an episode of pneumonia not associated with mechanical ventilation” and states that patients with HAP and VAP “belong to 2 distinct groups.” The same guideline reflects “the removal of the concept of healthcare-associated pneumonia (HCAP)” as a category. In everyday use, “ventilator-acquired” and “ventilator-associated” refer to the same condition; the published guidance uses “ventilator-associated.”
This page is an overview for laboratory, clinic and procurement staff who meet the term in guidance documents, accreditation material and supplier conversations. It is general information, not clinical advice, and it does not describe bedside procedures.
How VAP is handled in practice
Two different questions: clinical diagnosis and surveillance
Clinicians and infection preventionists use VAP in two different ways, and the definitions are not interchangeable. The CDC National Healthcare Safety Network (NHSN) states that its ventilator-associated event (VAE) algorithm “is for use in surveillance. It is not a clinical definition algorithm and is not intended for use in the clinical management of patients.” NHSN replaced VAP-only surveillance in adult patient locations with the three-tier VAE approach (VAC, IVAC and PVAP), explaining that “there is currently no valid, reliable definition for VAP.” Pediatric VAP (PedVAP) and the older pneumonia definitions remain available for pediatric locations and off-plan use. For the surveillance criteria themselves, see the CASRAI guide to the ventilator-associated event (VAE) definitions; they are not repeated here.
What the clinical guideline says about diagnosis and treatment duration
The IDSA/ATS guideline makes a few headline recommendations that are frequently quoted:
- It suggests “noninvasive sampling with semiquantitative cultures to diagnose VAP” (a weak recommendation, low-quality evidence).
- It recommends using clinical criteria alone, rather than adding procalcitonin, to decide whether to start antibiotics (strong recommendation, moderate-quality evidence).
- For patients with VAP it recommends “a 7-day course of antimicrobial therapy” (strong recommendation, moderate-quality evidence).
These are guideline positions for clinicians, quoted here for context. Treatment decisions belong to the treating team.
Prevention: what the 2022 Compendium lists
The SHEA/IDSA/APIC Strategies to Prevent Ventilator-Associated Pneumonia, Ventilator-Associated Events, and Nonventilator Hospital-Acquired Pneumonia in Acute Care Hospitals: 2022 Update was published on May 20, 2022 (Infect Control Hosp Epidemiol 2022;43:687-713, doi 10.1017/ice.2022.88). It addresses adults, children and neonates. The CDC describes the Compendium as separating “essential practices” that “should be adopted by all acute care hospitals” from additional approaches. For adults, the essential practices it lists include:
| Area | Compendium wording | Evidence quality given |
|---|---|---|
| Avoiding intubation | Use high-flow nasal oxygen or noninvasive positive pressure ventilation as appropriate whenever safe and feasible | High |
| Sedation | Minimize sedation of ventilated patients whenever possible; use a protocol to minimize sedation; implement a ventilator liberation protocol | High |
| Physical conditioning | Provide early exercise and mobilization | Moderate |
| Head of bed | Elevate the head of the bed to 30-45 degrees | Low |
| Oral care | Provide daily oral care with toothbrushing but without chlorhexidine | Moderate |
| Nutrition | Provide early enteral rather than parenteral nutrition | High |
| Ventilator circuits | Change the ventilator circuit only if visibly soiled or malfunctioning | High |
The same document lists several measures as not recommended for routine VAP/VAE prevention, including chlorhexidine oral care, probiotics, stress-ulcer prophylaxis, and a group of endotracheal-cuff designs and cuff-pressure monitoring approaches. Subglottic secretion drainage and early tracheostomy are classified as additional approaches rather than essential practices.
Related terms compared
| Term | What it means in the sources above |
|---|---|
| VAP | Pneumonia in a patient receiving mechanical ventilation; a group distinct from HAP in the IDSA/ATS guideline |
| HAP | “An episode of pneumonia not associated with mechanical ventilation” (IDSA/ATS 2016) |
| HCAP | A category the 2016 IDSA/ATS guideline reflects the removal of |
| VAE (VAC, IVAC, PVAP) | NHSN’s adult surveillance algorithm; explicitly not a clinical definition |
| NV-HAP | Nonventilator hospital-acquired pneumonia, covered alongside VAP and VAE in the 2022 Compendium |
Where it matters for labs, clinics and supply decisions
For staff who support hospital infection-prevention programs, the practical point is which document governs which decision. The Compendium frames practices at the level of hospital policy, and it advises changing the ventilator circuit “only if visibly soiled or malfunctioning,” so circuit-change frequency is a protocol question rather than a calendar one. NHSN data are surveillance measures used for reporting, while the IDSA/ATS guideline addresses clinical care. Mixing the two is the most common source of confusion in quality reports. Related reading: the CASRAI guides to navigating the NHSN Patient Safety Component Manual, nurse-sensitive indicators, CLABSI and enhanced barrier precautions.
Common misunderstandings
- “VAP and VAE are the same thing.” They are not. VAE is a surveillance construct; NHSN states it is not a clinical definition.
- “VAP is the same as HAP.” The IDSA/ATS guideline treats them as two distinct groups.
- “Chlorhexidine mouthwash is a standard prevention step.” The 2022 Compendium lists daily oral care with toothbrushing but without chlorhexidine as the essential practice, and lists chlorhexidine oral care as not recommended.
- “Antibiotic courses for VAP must be long.” The guideline recommends a 7-day course rather than a longer duration.
- “HCAP is still a category.” The 2016 guideline reflects its removal.
Frequently asked questions
Is ventilator-acquired pneumonia the same as ventilator-associated pneumonia?
The terms are used interchangeably for pneumonia in a mechanically ventilated patient. Guidelines and surveillance documents use “ventilator-associated.”
What is the difference between VAP and a ventilator-associated event?
VAP is a clinical concept. A ventilator-associated event is a CDC NHSN surveillance category (VAC, IVAC, PVAP) that NHSN says is not a clinical definition.
How is VAP different from hospital-acquired pneumonia?
The IDSA/ATS guideline defines HAP as pneumonia not associated with mechanical ventilation and places VAP in a separate group.
How long does the guideline recommend treating VAP?
The IDSA/ATS guideline recommends a 7-day course of antimicrobial therapy for VAP. Decisions for individual patients rest with the treating clinicians.
Which practices does the 2022 Compendium call essential?
For adults they include avoiding intubation where safe, minimizing sedation, early mobilization, head-of-bed elevation, daily toothbrushing without chlorhexidine, early enteral nutrition and changing ventilator circuits only when visibly soiled or malfunctioning.
Sources
- Kalil AC et al. Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by IDSA and ATS. Clin Infect Dis 2016;63(5):575-582. https://academic.oup.com/cid/article/63/5/575/2237827 (checked 2026-10-28).
- SHEA/IDSA/APIC. Strategies to Prevent Ventilator-Associated Pneumonia, Ventilator-Associated Events, and Nonventilator Hospital-Acquired Pneumonia in Acute Care Hospitals: 2022 Update. Infect Control Hosp Epidemiol 2022;43:687-713. https://doi.org/10.1017/ice.2022.88 (checked 2026-10-28).
- CDC. Compendium 2022 update: strategies for healthcare-associated infections. https://www.cdc.gov/patient-safety/stories/compendium-2022-update-strategies-for-hais.html (checked 2026-10-28).
- CDC NHSN Patient Safety Component Manual, Chapter 10, Ventilator-Associated Event (VAE) protocol. https://www.cdc.gov/nhsn/pdfs/pscmanual/10-vae_final.pdf (checked 2026-10-28).
