Central line-associated bloodstream infection: Clinical sciences

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Introduction0:00–1:20

Central line-associated bloodstream infection, or CLABSI for short, is a primary bloodstream infection that develops at least 48 hours after central line placement when no other source of infection is identified.
CLABSI also refers to a primary blood infection that occurs on the day of central line removal or the day after. Now, the most common causes of CLABSI include bacteria, such as coagulase-negative staphylococci, Staphylococcus aureus, and enterococci.
Less commonly, CLABSI can be caused by fungi, such as Candida. These pathogens can colonize the central line and use its extraluminal or intraluminal surface to reach the bloodstream.
Extraluminal migration is usually specific for organisms that represent a part of normal skin microflora, while intraluminal migration is associated with contamination of the central line, typically from the hands of health care providers.
CLABSI can be defined as complicated when the patient has CLABSI with septic shock, septic thrombophlebitis, or metastatic infection; while uncomplicated is CLABSI without these associated complications.Now, if you suspect CLABSI, you should first perform an ABCDE assessment to determine if your patient is unstable or stable.

Unstable patients1:20–1:49

If the patient is unstable, stabilize the airway, breathing, and circulation. This means that you might need to intubate the patient.
Next, obtain IV access, and, if your patient is hypotensive, start IV fluids for volume resuscitation. Once you are done with the acute management, obtain a focused history and physical examination, and order labs, including CBC and lactate.

History, Physical examination, Labs1:49–2:41

History typically reveals a central line that’s been in place for more than 2 days, and symptoms such as fever, chills, and fatigue.
But, keep in mind that CLABSI can also occur once the central line is removed. In this case, the patient might report symptoms on the day of, or the day after, the catheter removal.
Physical exam findings might reveal hypotension and altered mental status, including confusion or lethargy. Additionally, at the central line insertion site, you might detect local erythema, tenderness, and purulence.
Finally, lab results typically include elevated WBCs and lactate.Now that you’ve obtained the history, physical, and lab findings, you should assess for other sources of infection.

Assess for the source of infection2:41–3:14

If there’s another source of infection that can explain current signs and symptoms, such as urinary tract infection or surgical site infection, you should suspect a secondary bloodstream infection.
However, if you find no other source of infection, you should suspect complicated CLABSI, defined as CLABSI with septic shock, septic thrombophlebitis, or metastatic infection.Once you suspect complicated CLABSI, draw two or more blood samples for culture.

Complicated CLABSI suspected3:14–4:00

Do this on two separate occasions to avoid possible false positive results due to contamination. In other words, draw samples from different sites, or at different times.
For example, you can draw samples from two different peripheral sites, or you can draw one sample from a peripheral site and one from the lumen of the central line.
Avoid drawing blood samples from the lumen only, since cultures drawn through the central line have a higher rate of contamination.
Finally, once you have drawn blood cultures and are waiting for results, start empiric antibiotics and remove the central line.Alright, now, let’s take a look at how to assess blood culture results.

Assess BC results, treatment4:00–5:01

If both cultures come back negative, you should consider an alternative diagnosis. On the flip side, you can diagnose complicated CLABSI if at least one blood culture comes back positive for bacteria that are true pathogens, meaning for bacteria that are not a part of human microflora.
Additionally, you can diagnose complicated CLABSI if two blood cultures come back positive for bacteria that are commensal organisms, meaning bacteria that represent a part of normal microflora.
Now that you’ve diagnosed complicated CLABSI, switch to tailored antibiotics based on culture results. The antibiotic therapy should last 4 to 6 weeks, unless there's underlying osteomyelitis, which requires an additional 2 weeks of treatment.
Finally, keep in mind that your culture results might come back positive for fungi, so in that case, switch from empiric antibiotics to antifungals!Now let’s go back to the ABCDE assessment and discuss what to do for stable patients.

Stable branch5:01–5:50

Start by obtaining a focused history and physical examination, as well as labs, such as CBC. Just like in unstable individuals, history typically reveals a central line that’s been in place for more than 2 days, and symptoms such as fever, chills, and fatigue.
Additionally, CLABSI can occur after a central line is removed, with symptoms developing the same day or the day after. On a physical exam, keep an eye on the central line insertion site, which can reveal local erythema, tenderness, and purulence.
Finally, lab findings may reveal elevated white blood cell count, which is common in bacterial infections. Now that you’ve obtained the history, physical, and lab findings, assess for other sources of infection.

Assess for the source of infection5:50–6:36

Again, if you find another source of infection, you should suspect secondary bloodstream infection. However, if you find no other source of infection, suspect CLABSI.Next, draw two or more blood samples for culturing on two separate occasions.
Again, to avoid false positive results from contamination, either draw samples from two different peripheral sites, or draw one sample from a peripheral site and one from the lumen of the central line.
While you are waiting for culture results, don’t forget to start empiric antibiotics. Also, unless the benefit strongly outweighs the risk of keeping the central line, remove it!Now, let’s switch gears and move on to blood culture results.

Assess BC results, treatment6:36–7:28

If both cultures come back negative, you should consider an alternative diagnosis. On the other hand, if at least one blood culture comes back positive for bacteria that are true pathogens, or two blood cultures come back positive for bacteria that are commensal organisms, you can diagnose CLABSI.
Once you have confirmed CLABSI, switch to tailored antibiotics based on culture results. On the other hand, if cultures come back positive for fungi, switch to antifungals.
Next, remove the central line, if not done already. In cases where you can’t remove the central line due to ongoing need, use a guidewire to remove the old catheter and put the new one through the same opening and tract.
Alternatively, you can place a new central line at a completely different location.Now, give your patient some time to respond to the treatment and assess their response by observing for clinical improvement and obtaining follow-up blood cultures.

Assess the treatment response7:28–8:19

The adequate response includes resolution of signs and symptoms, as well as negative follow-up blood cultures. In these individuals, you should suspect uncomplicated CLABSI and continue the current antibiotic therapy, as well as place a new central line.
On the other hand, inadequate response refers to a persistent fever that lasts more than 72 hours, or positive follow-up blood cultures after 48 hours.
In these individuals, you should suspect complicated CLABSI and extend the current antibiotic therapy for at least 4 to 6 weeks.
In addition, persistent bacteremia should raise suspicion for metastatic infection and prompt further testing for this.Alright, as a quick recap… If you suspect CLABSI, you should perform an ABCDE assessment, to determine if your patient is unstable or stable.

Review8:19–9:44

If unstable, stabilize the patient and assess for the source of infection. If there's no other source of infection, suspect complicated CLABSI.
Next, obtain two or more samples for blood cultures, start empiric antibiotics, and remove the central line. Negative blood cultures rule out CLABSI, while positive cultures confirm the diagnosis of complicated CLABSI, so continue tailored antibiotics for the next 4 to 6 weeks.
Similarly, in stable individuals, you should first assess the source of infection. If there's no other source of infection, suspect CLABSI.
Obtain two or more samples for blood cultures, start empiric antibiotics and consider removing the central line. Negative blood cultures rule out CLABSI, while positive ones confirm the diagnosis.
Based on culture results, switch to tailored antibiotics and remove the central line or replace it with a new one. Finally, assess the patient’s response to the treatment.
If they respond adequately, complete the antibiotic therapy. If not, you should consider complicated CLABSI and extend the antibiotic therapy for at least 4 to 6 weeks, in addition to evaluating for metastatic infection.
Central line-associated bloodstream infection | Osmosis