Better understanding the home care environment

While hospital acquired infections (HAIs) threaten the wellbeing of many patients, those who are immunocompromised or immunosuppressed, such as hematopoietic stem cell transplant (HSCT) recipients, are at particular risk. Such patients are vulnerable to infections from other people (e.g., visitors, other patients, HCWs), the environment (e.g., surfaces, unfiltered air, linens), and themselves (e.g., pathogens shed from their own GI tract).

Infection is a significant cause of mortality in this population in the months following transplant and considerable care is taken to protect patients in the hospital. When they are well enough, recipients are released to go home and receive care there, with periodic visits to clinic. Typically, they and their home care providers are trained on how to prevent infections (e.g., through appropriate central venous line care, wearing of masks, etc), and sometimes home care nurses visit to ensure appropriate care is delivered. Medical supplies (infusion pumps, line care kits, saline, heparin, etc) are delivered; the house becomes a mini-hospital for care of the patient.

The approach seems to work well from an infection prevention perspective, but it's hard to be sure given the paucity of studies in the literature on the incidence of infections in home care populations. If the home care environment is protective to the patient, it's important to understand why that is, and if it's a threat, it's important to know that as well. Understanding the risk of infection in this patient population at home versus in highly controlled environments is important.

On the one hand, there's a different infection pressure in the home relative to a hospital. Presumably it's decreased at home, as there are no surrounding patients and there are fewer contacts with HCWs per unit of time. On the other hand, there is risk from contact with their home care providers, who often interact with many other people outside the home daily.

Moreover, the microbial environment of the home, as it relates to hematology/oncology patient health, doesn't seem to be as well characterized as that of the hospital environment. Looking through the literature that does exist isn't entirely reassuring. Whereas in bone marrow transplant (and related) wards there is extensive guidance on air filtration, cleaning procedures, and protocols for visitors, the analogous issues (e.g., ventilation, dust, cleaning) in homes are much more variable. The presence of pets may add additional risk. Furthermore, recovering patients often travel to and from hospital clinics on a daily or weekly basis. The automobile can also be a mode for infection, as has been pointed out recently for Legionella.

Improved surveillance for home care infections could lead to a better knowledge of the epidemiology of these infections and potentially identification of modifiable risk factors. 

(image source: Wikipedia)