[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Conditions](https://durgical.com/en/conditions/) › Hospital-acquired and ventilator-associated pneumonia

[Conditions](https://durgical.com/en/conditions/) · [Pulmonology](https://durgical.com/en/conditions/)

# Hospital-acquired and ventilator-associated pneumonia

A lung infection that starts in hospital, at least two days after admission, or in people on a breathing machine. It is a leading hospital infection.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Right lower lobe](https://durgical.com/en/anatomy/inferior-lobe-of-right-lung/)
- [Trachea](https://durgical.com/en/anatomy/trachea/)
- [Left lower lobe](https://durgical.com/en/anatomy/inferior-lobe-of-left-lung/)
- [Main bronchi](https://durgical.com/en/anatomy/right-main-bronchus/)
- [Segmental bronchi](https://durgical.com/en/anatomy/segmental-bronchus/)
- [Pleura](https://durgical.com/en/anatomy/pleura/)

## In the clinical exam

- [Consolidation syndrome](https://durgical.com/en/clinical-exam/consolidation-syndrome/)

## Why it happens

- [Patterns of acute inflammation: serous, fibrinous, purulent, abscess, ulcer](https://durgical.com/en/general-pathology/patterns-of-acute-inflammation-serous-fibrinous-purulent-abscess-ulcer/)
- [Leukocyte recruitment: rolling, adhesion, transmigration, chemotaxis](https://durgical.com/en/general-pathology/leukocyte-recruitment-rolling-adhesion-transmigration-chemotaxis/)
- [Airway defenses, cough and mucociliary clearance](https://durgical.com/en/physiology/airway-defenses-cough-and-mucociliary-clearance/)
- [The airway: from nose to bronchioles](https://durgical.com/en/histology/the-airway-from-nose-to-bronchioles/)

## What it is

Hospital-acquired pneumonia (HAP) is pneumonia that appears 48 hours or more after admission and was not incubating at entry. Ventilator-associated pneumonia (VAP) is the subtype that appears 48 hours or more after endotracheal intubation.

## Who gets it

One of the most frequent healthcare-associated infections and the leading infection in intensive care units. In Latin American and Colombian ICUs, surveillance of device-associated infections includes VAP, and multidrug-resistant gram-negative bacteria are a growing problem.

## Causes

- Gram-negative bacilli: Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterobacter and Acinetobacter
- Staphylococcus aureus, including methicillin-resistant strains (MRSA)
- Polymicrobial infection is common; viruses and fungi are less frequent
- Microaspiration of colonised oropharyngeal or gastric secretions, and secretions pooling around the endotracheal tube cuff

## Risk factors

- Endotracheal intubation and mechanical ventilation (the strongest risk)
- Lying flat, reduced consciousness, sedation and swallowing problems
- Older age, chronic lung disease and immunosuppression
- Recent intravenous antibiotics (risk of resistant organisms)
- Thoracic or upper abdominal surgery, nasogastric tubes and long hospital stay

## Pathophysiology

Within days of admission the mouth and throat become colonised by hospital bacteria. Secretions are aspirated in small amounts past a weakened cough or around the endotracheal tube cuff, and the tube and its biofilm bypass normal airway defences. Bacteria multiply in the dependent lower lobes and trigger an inflammatory exudate that fills alveoli and impairs gas exchange.

## Classification

- Hospital-acquired pneumonia (not ventilated): 48 hours or more after admission
- Ventilator-associated pneumonia: 48 hours or more after intubation
- By risk of multidrug-resistant organisms and of death, which guides empiric therapy

## Symptoms and signs

- New fever or hypothermia
- Cough with purulent sputum, or more and thicker tracheal secretions in ventilated patients
- Shortness of breath and fast breathing
- Falling oxygen saturation or rising oxygen needs on the ventilator
- New confusion, especially in older adults
- Crackles or bronchial breath sounds over the affected area

## Red flags

- Septic shock (low blood pressure, rising lactate)
- Rapidly worsening hypoxaemia or need for intubation
- Multilobar or cavitating infiltrates
- No improvement after 48–72 hours of treatment

## Diagnosis

**Clinical**
A new or progressive infiltrate on imaging plus clinical signs of infection (fever, purulent secretions, leucocytosis or leucopenia, worsening oxygenation). No single sign is diagnostic.

**Tests**
Respiratory samples before starting antibiotics if possible: sputum, or endotracheal aspirate in ventilated patients, with Gram stain, culture and susceptibility. Blood cultures, blood count, procalcitonin as a supporting test, lactate and blood gases.

**Imaging**
[Chest](https://durgical.com/en/anatomy/region/chest/) X-ray showing a new or progressive infiltrate, often in the lower lobes; lung ultrasound at the bedside; CT when X-ray is unclear or complications are suspected.

## Differential diagnosis

- Atelectasis
- Cardiogenic pulmonary oedema
- ARDS
- Pulmonary embolism with infarction
- Aspiration pneumonitis (chemical, non-infectious)
- Drug-induced lung injury or pulmonary haemorrhage

## Goal of treatment

Start effective empiric antibiotics quickly according to local resistance patterns, then narrow them with culture results and keep the course as short as clinically safe; support oxygenation and prevent further cases.

## Treatment

**Medical**
Empiric intravenous antibiotics guided by the local antibiogram and risk of resistance: antipseudomonal beta-lactams (piperacillin-tazobactam, cefepime, carbapenems) with an anti-MRSA agent (vancomycin or linezolid) when indicated; de-escalation once cultures return; about 7 days for most patients.

**Acute**
Supplemental oxygen, ventilatory support and sepsis management (fluids, vasopressors) as needed.

**Follow-up**
Daily review of temperature, secretions, oxygenation, white cell count and cultures to adjust or stop antibiotics.

**Conservative**
VAP prevention bundle, an NCLEX priority: head of bed elevated 30–45 degrees, daily sedation interruption and assessment for extubation, oral care, subglottic secretion drainage and correct cuff pressure, hand hygiene, and early mobilisation.

## Drugs for this condition

- [Tobramycin](https://durgical.com/en/pharmacology/tobramycin/)
- [Meropenem](https://durgical.com/en/pharmacology/meropenem/)
- [Imipenem–cilastatin](https://durgical.com/en/pharmacology/imipenem-cilastatin/)
- [Aztreonam](https://durgical.com/en/pharmacology/aztreonam/)
- [Linezolid](https://durgical.com/en/pharmacology/linezolid/)

## Complications

- Sepsis and septic shock
- Acute respiratory failure and ARDS
- Parapneumonic effusion and empyema
- Lung abscess
- Infection by multidrug-resistant organisms and Clostridioides difficile after antibiotics
- Longer ventilation, ICU stay and higher mortality

## Prognosis

Carries higher mortality than community-acquired pneumonia, especially VAP and infections with resistant gram-negative bacteria. Early appropriate antibiotics and good baseline health improve the outcome.

## Prevention

- Hand hygiene and contact precautions
- Semi-recumbent position and oral care
- Avoiding intubation when non-invasive support works, and the shortest possible time on the ventilator
- Early mobilisation and incentive spirometry after surgery
- Antibiotic stewardship

## Test yourself

Think of the answer, then tap the question to see it.

## How are hospital-acquired and ventilator-associated pneumonia defined in time?

HAP appears 48 hours or more after admission; VAP appears 48 hours or more after endotracheal intubation.

## Which organisms must empiric therapy for HAP/VAP often cover?

Gram-negative bacilli including Pseudomonas aeruginosa, and Staphylococcus aureus including MRSA when risk factors are present.

## What are three elements of the VAP prevention bundle?

Head of bed at 30–45 degrees, daily sedation interruption with assessment for extubation, and oral care (plus hand hygiene and cuff/subglottic suction).

## What is the main mechanism of infection in VAP?

Microaspiration of colonised oropharyngeal secretions that leak around the endotracheal tube cuff, aided by the tube biofilm.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/conditions/hospital-acquired-and-ventilator-associated-pneumonia/)

## Related conditions

- [Community-acquired pneumonia](https://durgical.com/en/conditions/community-acquired-pneumonia/)
- [Aspiration pneumonia and pneumonitis](https://durgical.com/en/conditions/aspiration-pneumonia-and-pneumonitis/)
- [Acute respiratory failure (hypoxaemic and hypercapnic)](https://durgical.com/en/conditions/acute-respiratory-failure/)
- [Acute respiratory distress syndrome (ARDS)](https://durgical.com/en/conditions/acute-respiratory-distress-syndrome/)
- [Sepsis and septic shock](https://durgical.com/en/conditions/sepsis-and-septic-shock/)
- [Pleural effusion](https://durgical.com/en/conditions/pleural-effusion/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Hospital-acquired pneumonia: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/000146.htm) (MedlinePlus (U.S. National Library of Medicine), 2024); Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society (Clinical Infectious Diseases, 2016).

[← All conditions](https://durgical.com/en/conditions/)

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/conditions/hospital-acquired-and-ventilator-associated-pneumonia/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/hospital-acquired-and-ventilator-associated-pneumonia/