Bacteremia

Bacteremia is not sepsis - Bacteria in the blood is a positive culture. Sepsis is organ dysfunction from a dysregulated host response, and the findings that move a patient across that line are SBP under 90 mmHg, MAP under 65 mmHg, lactate over 2 mmol/L, aPTT over 60 seconds, or a new requirement for invasive or non-invasive ventilation. Sort out which patient you have before you write the plan.

Find the source before you induce - Two sets of blood cultures drawn sterilely from two different sites, plus a lactate, is the floor. Chest x-ray and urinalysis with culture cover the common sources; wound cultures and CT of the operative field find postoperative abscesses and collections. Indwelling venous catheters, dialysis catheters, and ports come out and the tips go to culture — the line you were about to use may be the source.

Get the antibiotic in - Delay in appropriate antibiotics tracks directly with morbidity and mortality, so the first dose should not wait on room turnover. Before the Gram stain returns that means broad gram-positive and gram-negative cover with an extended-generation cephalosporin or a beta-lactamase inhibitor, Pseudomonas cover for hospital-acquired disease or recent healthcare exposure, and vancomycin added for MRSA. Standard preoperative timing is within 60 minutes of incision; IV vancomycin is the exception and goes in two hours ahead.

Endocarditis prophylaxis is narrower than most charts assume - Since the 2007 AHA revision it applies only to prosthetic cardiac valves, previous infective endocarditis, cardiac transplant recipients with valve regurgitation through a structurally abnormal valve, and specified congenital heart disease. Amoxicillin 2 g orally one hour before, or ampicillin or ceftriaxone IV; cephalexin or azithromycin for penicillin allergy. Clindamycin is no longer recommended because of its adverse-reaction profile, and azithromycin deserves caution in anyone with a QTc over 450 ms.

No prophylaxis for the scopes - TEE, EGD, colonoscopy, and cystoscopy do not warrant endocarditis prophylaxis in the absence of active infection, and neither do dental procedures in patients with coronary stents or prior CABG. Implantable cardiac devices are the exception: an anti-staphylococcal antibiotic at implantation and at any later manipulation of the device pocket.

Think hard before instrumenting the neuraxis - Bacteremia is an established risk factor for spinal epidural abscess, and so is direct instrumentation — lumbar puncture, paraspinal or epidural injection, epidural catheterization. A quarter to half of spinal epidural abscesses arrive hematogenously. Diabetes is the single most common risk factor and epidural catheters are a rising one. If a catheter goes in anyway, back pain plus fever plus rising inflammatory markers is the trigger for a contrast MRI, not for more analgesia.

Hemodynamics once it tips - Target MAP above 65 mmHg. Norepinephrine is the first vasopressor, with vasopressin added if norepinephrine titration alone does not get there. Resuscitate with crystalloid; balanced solutions such as lactated Ringer's may edge out normal saline. Follow lactate and venous oxygen saturation as severity markers rather than the blood pressure alone — hyperlactatemia in sepsis is metabolic as well as hypoperfusion, so it lags behind the fix.

A new murmur means echo before an elective case - Bacteremia seeds the endocardium and can produce valvular vegetations or a myocardial abscess. Transthoracic echo is the first study and transesophageal adds resolution. Absence of vegetation does not exclude endocarditis, and lesions over 1 cm predict embolic complications.

You lose the classic presentation under anesthesia - Fever is the classic sign, with chills and rigors sometimes but not always. General anesthesia blunts the fever and removes the rigors entirely, so track temperature actively and read a rising lactate or falling urine output as the same signal you would have gotten at the bedside.

Bacteremia is viable bacteria in the blood. Transient, asymptomatic bacteremia happens with ordinary things — brushing teeth, minor procedures — and a healthy host clears it without sequelae. It matters when immune mechanisms are overwhelmed and it becomes a true bloodstream infection, which can progress through SIRS to sepsis, septic shock, and multiple organ dysfunction syndrome.

Finding the source drives everything. In hospitalized patients it is usually the respiratory tract or an indwelling catheter, especially a central venous catheter; untreated urinary tract infection is the most common community-acquired source; soft-tissue and intra-abdominal sources show up in postoperative surgical patients. Escherichia coli is the most common gram-negative isolate and Staphylococcus aureus the most common gram-positive one. Skin and mucosa are the first barrier, so anything that crosses them — needles, catheters, incisions, trauma, burns, ulcers — is a portal. Left alone it seeds endocardium, bone, meninges, and the epidural space.