3.6 Surveillance Across the Care Continuum
Key Takeaways
- Long-term care facilities use the revised McGeer criteria rather than NHSN acute-care definitions, and the LTC fever threshold is a single oral temperature above 37.8°C or an increase of 1.1°C over baseline.
- Denominators change with the setting: acute care uses patient days and device days, long-term care uses resident days, dialysis uses patient-months, and home health uses visits or catheter days.
- Dialysis facilities report to the NHSN Dialysis Event module, where the three reportable events are a positive blood culture, intravenous antimicrobial start, and pus, redness, or swelling at the vascular access site.
- Ambulatory surgery centers and clinics concentrate risk in injection safety and device reprocessing rather than in device-associated infection rates.
- Congregate behavioral health settings drive outbreaks through shared living space, group activities, and limited hand hygiene infrastructure rather than through invasive devices.
3.6 Surveillance Across the Care Continuum
Quick Answer: Surveillance definitions and denominators are setting-specific. Acute care uses NHSN definitions with patient days and device days. Long-term care uses the revised McGeer criteria with resident days. Dialysis uses the NHSN Dialysis Event module with patient-months. Applying an acute-care definition to a nursing home resident is a classic surveillance error.
Infection prevention has moved outward from the hospital. Most surgery is now ambulatory, most chronic care is delivered in long-term and home settings, and patients move between all of them carrying their organisms with them.
Setting-by-Setting Comparison
| Setting | Definitions | Denominator | Dominant risks |
|---|---|---|---|
| Acute care | NHSN Patient Safety Component | Patient days, device days, procedures | CLABSI, CAUTI, VAE, SSI, MRSA/CDI LabID events |
| Long-term care | Revised McGeer criteria; NHSN LTCF Component | Resident days | UTI, respiratory infection, gastroenteritis, skin/soft tissue, scabies |
| Ambulatory surgery center | NHSN ASC module; procedure-based | Procedures | SSI, injection safety, reprocessing failures |
| Ambulatory clinic / physician office | Largely local; no national mandate | Visits or procedures | Injection safety, point-of-care device reprocessing, vaccine handling |
| Outpatient hemodialysis | NHSN Dialysis Event module | Patient-months | Access-related bloodstream infection, hepatitis B transmission |
| Home health / home infusion | Adapted definitions; no national standard | Visits, catheter days, infusion days | Central line infection, wound infection, caregiver technique |
| Behavioral health | Syndromic and outbreak-based | Resident or patient days | Gastroenteritis, respiratory outbreaks, scabies, tuberculosis |
Long-Term Care: The McGeer Criteria
Nursing home residents differ from hospital inpatients in ways that break acute-care definitions. They are older, frequently afebrile when infected, often cognitively impaired and unable to report symptoms, and rarely have same-day imaging or laboratory access. The revised McGeer criteria were developed for exactly this population.
Constitutional criteria in long-term care
Fever in a resident is defined as any of:
- A single oral temperature >37.8°C (100°F), or
- Repeated oral temperatures >37.2°C (99°F) or rectal temperatures >37.5°C (99.5°F), or
- An increase of >1.1°C (2°F) over the resident's baseline temperature
That last clause matters enormously: an older adult whose baseline is 36.1°C and who registers 37.4°C is febrile even though no threshold was crossed.
Other constitutional criteria include acute change in mental status from baseline (using confirmed criteria of acute onset, fluctuating course, inattention, and disorganized thinking) and acute functional decline in activities of daily living.
Two structural rules
- All symptoms must be new or acutely worse, and
- Non-infectious causes must be excluded — a resident with new incontinence on a new diuretic does not have a urinary tract infection.
Exam Tip: McGeer UTI criteria for a catheterized resident do not require urinary symptoms, because the catheter bypasses the sensation. For a non-catheterized resident, localizing urinary signs are required. And in every case, a positive urine culture alone is never sufficient — asymptomatic bacteriuria is near-universal in this population.
Outpatient Hemodialysis
The NHSN Dialysis Event module counts three events in outpatient hemodialysis patients:
- Positive blood culture
- Intravenous antimicrobial start
- Pus, redness, or increased swelling at the vascular access site
The denominator is patient-months, collected as a census on the first two working days of the month. Access type drives risk: arteriovenous fistulas carry the lowest infection risk, grafts intermediate, and central venous catheters by far the highest, which is why "fistula first" is both a clinical and an infection prevention priority. Dialysis settings also carry a distinct hepatitis B transmission risk, requiring monthly HBsAg screening of susceptible patients, dedicated machines and isolation rooms for HBsAg-positive patients, and vaccination of susceptible patients and staff.
Ambulatory Surgery and Clinics
The defining ambulatory risk is not device-associated infection; it is breaches in basic technique that cause large exposure events:
- Reusing syringes or needles between patients, or reentering a single-dose vial
- Using a single-dose vial for multiple patients
- Failing to reprocess semi-critical devices such as endoscopes, laryngoscope blades, or vaginal probes between patients
- Point-of-care device sharing without disinfection — glucometers are the classic hepatitis B vehicle
Because patients are discharged within hours, post-discharge surveillance is the central methodological challenge for ambulatory SSI. Practical approaches include structured post-operative phone calls, review of readmission and emergency department returns, surgeon reporting, and linkage with the referring hospital's data.
Home Health and Home Infusion
No national surveillance system mandates home-care HAI reporting, so programs adapt definitions and choose a denominator such as catheter days or infusion days. The risks are distinctive:
- The caregiver, often a family member, performs line care with limited training
- The home has no engineering controls, no dedicated clean space, and variable refrigeration
- Supply storage, pets, and household activity create contamination opportunities
- Education and return demonstration are the primary interventions, not environmental engineering
Behavioral Health and Congregate Settings
Psychiatric units and residential behavioral health facilities have few invasive devices but high congregate risk: shared bedrooms and bathrooms, group therapy and dining, prolonged length of stay, and residents who may not perform hand hygiene or respiratory etiquette reliably. Ligature-risk restrictions also limit the alcohol-based hand rub dispensers and other fixtures that a medical unit takes for granted, so hand hygiene must be engineered around safety requirements. Surveillance is therefore syndromic and outbreak-oriented — clusters of diarrhea, respiratory illness, scabies, or conjunctivitis — rather than device-rate based.
Transitions of Care
Whatever the setting, organisms travel with patients. A structured inter-facility transfer communication form should convey MDRO colonization status, active precautions, pending cultures, current antimicrobials, and any device in place. Failure to communicate at transfer is one of the most common contributors to regional MDRO spread, and it is an explicit blueprint task under communication as well as surveillance.
A nursing home resident with a baseline temperature of 36.2°C now registers 37.5°C orally, with new confusion. Under the revised McGeer criteria, does this resident meet a constitutional criterion for fever?
Which three events are reportable to the NHSN Dialysis Event module for outpatient hemodialysis patients?
An ambulatory surgery center wants to measure surgical site infections but patients are discharged within four hours. What is the principal methodological challenge and an appropriate solution?
Why is surveillance in a residential behavioral health facility primarily syndromic and outbreak-oriented rather than device-rate based?