FAQs: Pneumonia (PNEU) Events

Ventilator-associated [VAP] and non-ventilator-associated Pneumonia [PNEU]

Lower Respiratory Tract Events

Q1:  I am confused about the different lower respiratory tract events that have definitions in NHSN – VAE, PedVAE, PedVAP, PNEU, and LRI. Can you explain to me how these do (or do not) relate to one another and where surveillance for each can be performed?

We know this can be an area of confusion. We need to consider events occurring in patients on mechanical ventilation and events occurring in patients NOT on mechanical ventilation, and we have to consider events that occur in adults and events that occur in neonates and in children. Let’s review what is available for in-plan or off-plan surveillance of lower respiratory tract events in NHSN. Keep in mind that “in-plan” surveillance means that you/your facility have committed to following the NHSN surveillance protocol for that particular event in your NHSN monthly reporting plan. “Off-plan” surveillance is surveillance that is done because you/your facility have decided to track a particular event for internal use. Data that are entered into NHSN “off-plan” are not used or reported in NSHN annual reports or other NHSN publications. A facility makes no commitment to follow the protocol for “off-plan” events.

What lower respiratory tract event surveillance can be done “in-plan”?

  1. VAE: This event is available for in-plan surveillance of mechanically ventilated inpatients in adult locations only (regardless of the age of the patient). Pediatric and neonatal locations are excluded from VAE surveillance (even in circumstances where a pediatric unit may occasionally care for adult patients).
  2. PedVAP: This event uses the PNEU protocol and is available for in-plan surveillance of mechanically ventilated inpatients in pediatric locations only (regardless of the age of the patient). In-plan surveillance for ventilator-associated PNEU (VAP) is not available for inpatients in adult or neonatal locations.
  3. PedVAE: This event is available for in-plan surveillance of mechanically ventilated inpatients in pediatric and neonatal locations only. Adult locations are excluded from PedVAE surveillance (even in circumstances where an adult unit may occasionally care for pediatric patients).

NOTE:  When conducting CLABSI surveillance, the PNEU definition is available for use as a site-specific infection to which a bloodstream infection can be attributed as a secondary BSI for all patients, all locations, regardless of use of mechanical ventilation. This includes ventilated or non-ventilated adults, children, or neonates in any patient location.

What lower respiratory tract event surveillance can be done “off-plan”?

  1.  VAE: VAE surveillance can be done “off-plan” in mechanically-ventilated inpatients in adult locations only.
  2.  PedVAP or PNEU/VAP: Surveillance using the PNEU protocol is available for “off-plan” surveillance in all mechanically-ventilated inpatients (adults, children, or neonates) in any inpatient location.
  3.  PedVAE: PedVAE surveillance can be done “off-plan” in mechanically-ventilated inpatients in neonatal and pediatric locations only.
  4. PNEU: PNEU surveillance is available for “off-plan” surveillance in non-mechanically-ventilated adults, children, and neonates in any inpatient location.
  5. LRI: Surveillance for non-pneumonia lower respiratory infections (using LUNG definition) is available for “off-plan” surveillance in mechanically-ventilated or non-mechanically-ventilated adults, children, and neonates.

VAE and PNEU/VAP surveillance; PedVAE and PedVAP surveillance

Q2: Can I conduct surveillance for VAE and PNEU/VAP in the same unit? Can I conduct surveillance for PedVAE and PedVAP in the same unit?

Yes. An adult location can conduct simultaneous in-plan VAE surveillance and off-plan PNEU/VAP surveillance. Likewise, a pediatric location can conduct simultaneous in-plan PedVAE and in-plan PedVAP surveillance, or a neonatal location can conduct simultaneous in-plan PedVAE and off-plan PedVAP surveillance. VAE is a separate event from PNEU/VAP, and PedVAE is a separate event from PedVAP. In other words, detection of one type of event (such as a VAE) in a particular patient would have no bearing on the conduct of surveillance for the other event type (PNEU/VAP) in the same patient. Patients who meet a VAE definition and a PNEU/VAP definition, or a PedVAE definition and a PedVAP definition, would have two events identified in units where surveillance for multiple respiratory events is occurring.

New and Persistent or Progressive and Persistent

Q3: How do I meet the imaging test requirement?

Imaging test evidence for pneumonia must be definitive. The findings must provide evidence suggestive of pneumonia. This includes but is not limited to new or worsening infiltrate, consolidation, opacity, or air space disease that is not attributed to something other than pneumonia


Evidence of persistence. There should not be rapid resolution of the finding or contradictory information in a subsequent imaging test which suggests the finding is attributable to another condition (for example, 2 days later the opacity is now attributed to pulmonary edema). Pneumonia may have rapid onset and progression but does not resolve quickly. Rapid imaging resolution suggests that the patient does not have pneumonia, but rather a non-infectious process.

One chest imaging test in some instances can be utilized to satisfy the imaging element of the pneumonia definitions; however, if subsequent imaging tests are available, the subsequent imaging tests must be assessed to make sure the requirement of persistence is satisfied. So, for any patient, regardless of underlying cardiac or pulmonary disease, all temporally-related subsequent imaging tests must be taken into consideration and must show persistence of eligible findings for the imaging requirement to be met. Subsequent imaging findings noting rapid clearing or attribution of imaging test findings to something other than pneumonia precludes the use of a prior finding. Point being, for all patients, you must look at the complete imaging picture, not just a select one or two imaging tests, when making a determination if the imaging requirement is met.

PedVAP surveillance and weaning

Q4: Are patients included in PedVAP surveillance during periods of time when they are undergoing weaning/mechanical ventilation liberation trials?

Yes. As long as the patient is receiving support from a mechanical ventilator for some portion of each calendar day he/she is eligible for PedVAP surveillance. Keep in mind, it is important to conduct your device day count at the same time every day and only include those patients on ventilator support at the time of the count. Therefore, we recommend ventilator day counts perhaps be conducted at night, so as to capture all eligible patients (to include those who are undergoing weaning) in the denominator for the location where surveillance is being conducted.


Excluded Pathogens

Q5: When referencing the pathogens that are excluded for meeting the PNEU definition, what does Candida species or yeast not otherwise specified, coagulase-negative Staphylococcus species, and Enterococcus species refer to?

This means the following are excluded:

All Candida species – those that have been identified to the species level such as Candida albicans, those that are reported as Candida species, and also to include culture reports that may simply say, for example, “many yeast isolated”

All coagulase-negative Staphylococcus species – for example, coagulase-negative Staphylococci, Staphylococcus epidermidis, Staphylococcus species

All Enterococcus species – for example, Enterococcus species, Enterococcus faecalis, VRE

Secondary BSI assignment to a PNEU event

Q6: What if a blood specimen collection date occurs outside the Infection Window Period of PNU1 or does not match the pathogen used to meet PNU2 or PNU3? Is it possible for a BSI to still be attributed to the PNEU event?

Yes, it is possible.

A secondary BSI cannot be attributed to PNU1. However, in this instance if a BSI is thought to be secondary to pneumonia but the blood culture collection date did not occur within the infection window period such that it could be used as an element to meet the PNU2 definition, reassess to determine if the PNU2 definition can be met within the PNEU RIT. Similarly, if PNU2 is met and there is a subsequent blood specimen with an eligible pathogen, however it does not match the specimen used to originally meet PNU2, then reassess to determine if PNU2 can be met using the blood culture such that the date of event falls within the originally established PNEU RIT.

NOTE: When re-meeting PNEU within the RIT, a single eligible imaging finding with a test date that occurs in a new IWP and demonstrates evidence of persistence of prior eligible findings will satisfy the imaging requirement for all patients. New or progressive or serial imaging (for patients with underlying cardiac or pulmonary disease) does not have to be re-demonstrated. Evidence of persistence of eligible findings alone will meet the imaging requirement in the RIT. See the example and table below.

All elements necessary to satisfy the PNU1 definition occur within the infection window period. The date of event is 2/14. This establishes a PNEU (PNU1) RIT 2/14- 2/27 and a BSI secondary attribution period 2/11 – 2/27. Subsequently a blood specimen with a collection date 2/20 identifies Pseudomonas aeruginosa. The collection date is within the secondary BSI attribution period for the PNEU event; however, a secondary BSI cannot be reported for PNU1 since the blood culture is not used to satisfy the PNU1 definition and there is no site-specific culture to which the blood culture pathogen can match. If during the PNEU RIT and within a new IWP, all elements needed to meet the PNU2 definition are present to include the blood specimen and this results in a date of event within the RIT, then the BSI can be attributed as secondary to the PNEU event. The PNEU date of event remains as 2/14, as does the originally determined RIT, secondary BSI attribution period, device association, and location of attribution. If the PNU2 definition is not met as described above and if additionally, another specific site infection for which the BSI can be attributed as a secondary BSI is not identified, then the BSI is a primary BSI/CLABSI.


VAP Table which lists the date, repeat infection timeframe, infection window period and secondary BSI attributable period.


Q7: PNU2 occurred in an infection window period (IWP), to include many E. coli identified from endotracheal aspirate. During the PNEU RIT but outside of the IWP 4+ S. aureus was identified from a BAL specimen, and the pathogen was added to the PNEU event. During the PNEU SBAP and also outside of the IWP a blood culture was collected with S. aureus identified. Can the BSI automatically be attributed as secondary to PNEU since it matches the added pathogen?

No. In order to cite the BSI as secondary to PNEU at least one organism from the blood specimen that was collected during the SBAP must match an organism identified from the site-specific specimen that was used to meet the infection criterion (Scenario 1 of the Secondary BSI Guide, Appendix B of the BSI protocol). In this case, PNU2 was met with the E. coli from the endotracheal aspirate so the BSI cannot be automatically assumed to be secondary to the PNEU event by matching pathogens. You will want to reassess to determine if the PNU2 definition can be met using the BAL with 4+ S. aureus in a new IWP such that the date of event falls within the originally established PNEU RIT. If so, the S. aureus BSI can be attributed as secondary to PNEU since the pathogen now matches a pathogen used to meet the PNEU definition. If PNU2 cannot be met using the BAL specimen, then you will want to reassess to determine if the PNU2 definition can be met using the blood specimen, as explained in Q6 above.

Use of sputum and endotracheal aspirate specimen results

Q8: Can identification of an eligible organism from sputum or endotracheal aspirate be used to satisfy the PNU2 or PNU3 laboratory finding?

Please note that the respiratory tract specimens eligible for satisfying the PNU2 laboratory findings specify that the specimen be a minimally contaminated lower respiratory tract specimen. This includes bronchial alveolar lavage (BAL), bronchial wash, protected specimen brushing, and endotracheal aspirate. Note endotracheal aspirate indicates the specimen is collected via an artificial airway. A sputum specimen that is not obtained through an artificial airway (specifically, endotracheal tube or tracheostomy) from a ventilated patient is not considered minimally contaminated and is not eligible for use in meeting the laboratory criteria. Specimens labelled sputum or tracheal secretions collected from a non-ventilated patient are not minimally-contaminated specimens and therefore are only available for use when meeting PNU3 laboratory finding of a matching Candida species identified in both sputum and blood with both specimen collection dates found in the same infection window period.

Imaging Test Results

Q9: When imaging test findings are not definitive for pneumonia but are equivocal what is the next step?

When findings are equivocal (for example, a report of infiltrate vs. atelectasis, or a report stating opacity may be pneumonia or may represent congestive heart failure) the first step is to look for subsequent imaging test results that provide a definitive result. This may be either a finding that is definitive for pneumonia and indicating persistence or a finding that is definitive for something other than pneumonia. If the latter, the imaging is not eligible for use in meeting the imaging requirement for PNEU. In the event subsequent imaging test results are not available or do not provide further delineation one way or another, then clinical correlation can be used. Clinical correlation requires that there is documentation in the medical record such that the physician is treating specifically for pneumonia.

Note: If subsequent imaging results indicate the finding is no longer equivocal but definitively attributed to something other than pneumonia clinical correlation is not available for use.

Breath Sounds

Q10: How is the requirement for bronchial breath sounds met?

Bronchial breath sounds are generally documented as such when heard upon auscultation. Documentation in the medical record of “bronchial breath sounds heard” will satisfy this requirement. If a physician/provider documents “bronchial breath sounds” the finding is considered abnormal as he/she is indicating he/she is hearing bronchial breath sounds in a place they should not be heard. If no documentation similar to this is found in the medical record for purposes of NHSN surveillance “bronchial breath sounds” were not heard and that element of the definition is not available for use in meeting a PNEU definition.

Bronchial breath sounds are a distinctive finding. Rhonchi are not bronchial breath sounds. Also, a descriptor preceding “breath sounds” (for example, coarse breath sounds, diminished breath sounds, etc.) is not bronchial breath sounds.


Q11. Are “coarse” or “diminished” breath sounds eligible to meet a PNEU definition?

Descriptors such as “coarse” breath sounds and “diminished” breath sounds, are not eligible findings for meeting PNEU for any patient. For all patients, documentation of rales/crackles or bronchial breath sounds are eligible findings for use in meeting PNU1, PNU2, and PNU3. When applying the alternate criteria for meeting PNU1 for infants ≤ 1 year old, documentation of wheezing, rales/crackles, or rhonchi are eligible findings.