Infection In Home Haemodialysis – It Can Be Sneaky!
While home patients and their supporting staff often fear venous disconnection most, and are correctly at pains to emphasize meticulous and careful taping, vigilance, and the use of leak detectors, the most insidious risk can be that of infection. Venous disconnection, in our experience, has not been a significant problem—providing that appropriate preventative measures and instruction is followed. But, infection? Well, that can be another matter altogether.
There is nothing that a home patient dreads more than having to be hospitalised. Their whole raison d’être is to be and to remain at home. To be admitted, to be forced back to facility care with facility rules and facility rosters—and, commonly, with far less dialysis than can be self-given at home—is anathema to home HD patients. It is everything that home patients go home to avoid. But, herein lies the chink in their armour!
Infection is the number one enemy of the home dialysis patient! Not obvious infection, like pneumonia, for most can identify chest infections more severe than a common cold, and seek help. No, the infection that can sneak under the guard of home patients is access infection.
There are three main types of access, and all—obviously—must penetrate skin to reach the venous blood stream. Peripheral access, an arteriovenous fistula (AVF) or graft (AVG), requires the insertion and removal of two needles each and every treatment through skin, while central access, commonly an internal jugular catheter (IJC), requires a double lumen (2 channel) catheter that also passes permanently through skin to dwell within the central venous system, the tip ideally floating free within the right atrium of the heart.
Peripheral access needs a minimum of 2 needles per treatment, and, while single needle dialysis is possible, for many reasons, it is not widely used. As a usual minimum of 3 treatments are delivered each week, 156 (3 x 52) treatments/year requires an annual minimum of 312 needle sticks with large bore (commonly 14 gauge) needles that remain (dwell) inside the access vessel for between 3 and 5+ hours (facility dialysis), or for between 8 and 9 hours (home nocturnal dialysis). Finally, as home dialysis is commonly delivered more frequently then centre-based dialysis, treatment frequencies anywhere between alternate day to 6 days/week are used. For the latter, 624 needle sticks—read breaches of skin—are required. Each breach carries risk, especially if using the buttonhole technique, and without meticulous care—or sometimes despite this—bugs get in!
In the case of a central access IJC, the catheter is, in effect, a foreign body that remains permanently in the venous blood stream…on, and on, and on. Even with the relative protection accorded by a cuffed catheter, the track from skin to central vein can be a highway for bug colonization and, ultimately, blood stream contact with the bugs that live outside.
Both carry risk: risk from poor skin preparation in the case of AVF or AVG needling; risk from tract infection or the introduction of bacteria or fungal spores if poor sterile technique complicates the connection and/or disconnection of a catheter. And, sometimes despite all care, bugs can be in the wrong place at the wrong time. The cannulation of the blood stream from the outside is undeniably a chancy business!
In addition, if an AVF or AVG needle is poorly secured and moves, sometimes almost imperceptibly, in and out of the skin (and vein) during the course of the dialysis, organisms may colonise the tract, or even be introduced without the “host” being aware of the invasion.
Shortly after the moment of bacteraemia (a shower of bugs released into the bloodstream) – a prodrome may occur. Prodromes are often not especially obvious, but may cause a sense of feeling a little “off color”…perhaps with a slight fever, or a shiver or two, and a sense of heat or coldness: vague, non-specific signs that a home patient may (indeed commonly will) shrug off, and ignore. This is especially so if the symptoms quickly settle – which they almost always do.
If a prodromal phase occurs to a patient on dialysis in a facility, more likely than not the temperature, the shiver, the complaint of ‘feeling unwell’ will be converted into a high index of suspicion by an alert nurse. Immediate blood cultures, blood tests, and a septic screen inevitably follow. But…at home, the same symptom set is more commonly shrugged off, especially if (a) the symptoms settle and (b) there is a fear that over-reporting may lead to a “come in the ER” instruction…and the threat of admission!
So…undetected… a bacteraemia can occur—especially at home—without coincident reporting. Some may be lucky, the bacteraemic shower passing without systemic infection. But some will not be so lucky, especially if there is calcification or other known (or unknown) valvular abnormalities in the heart valves…and endocarditis (an infection on the heart valves) results. But, as endocarditis can take weeks to develop into a full blown illness, the prodrome may be long forgotten by the time the more serious outcome of endocarditis appears.
Surface infection—redness around the insertion site, or a bead of pus or ooze from a recent puncture point—these, too, can be ignored with an “it’ll settle down” approach until the whole AVF surface is angry and inflamed. Here, a stitch in time saves nine, as they say, and early action with cultures, exclusion of systemic spread of infection, and (commonly) oral antibiotics can save more severe consequences down the track. Again, the home patient, independent to a fault, is at greatest risk.
Infection, even the merest hint of it, must never be ignored. Constant vigilance is needed. Aseptic techniques must be reinforced—again and again —while patient self-needling techniques should be checked, regularly, so that poor habits and corner cutting can be nipped in the bud.
Rob Pauly from Edmonton has written a particularly good assessment of the risks of home HD: Patient safety in home hemodialysis: quality assurance and serious adverse events in the home setting.” While this deals with many other potential risks, infection is a central component in his paper. While Rob clearly points out the extremely low frequency of adverse events in home haemodialysis patients, nonetheless, he makes a strong case for taking a prudent approach. Home patients must remain alert to the risks of infection. They must report any prodromal symptoms and, at the least, present to their home training units for a septic screen. Early detection is critical. Ignorance—or the classic “ostrich” syndrome—is not a smart approach!