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Episode 57: Bugs and Drugs Part 2 With Rachel Kruer

On this episode: Dr. Jed Wolpaw and Rachel Kruer

In this episode, episode 57, I welcome back Rachel Kruer, our amazing SICU pharmacist and we complete our two part series on bugs and drugs in the ICU. We discuss different infections that are commonly seen in ICUs and how to treat them.

Table of Contents Hyperlinks to section of notes.

EMPIRIC THERAPY CONSIDERATIONS 2

INTRAABDOMINAL INFECTIONS 2

BILIARY TRACT 2

PERITONITIS 3

PNEUMONIA 4

Community Acquired Pneumonia 4

Hospital Acquired Pneumonia 5

URINARY TRACT INFECTIONS 5

CASE EXAMPLE 6

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Empiric Therapy Considerations 00:39 – 3:10

- Common sources of infection: intraabdominal > pneumonia > UTI

o Source is important because:

What organisms colonize there

Antibiotics need good tissue penetration

- Empiric therapy considerations:

o Site + pathogens associated with site

o Severity of illness

Risk of mortality decreases when there is a shorter amount of time to

appropriate antibiotics

o Community vs. hospital acquired

Community less worried about pseudomonas, MRSA, etc.

- Narrowing therapy:

o Tailored when know source and source is controlled

o Stop vancomycin if resistant gram positive organisms are not cultured

o Important for stewardship efforts avoid broad spectrum when not necessary

Intraabdominal Infections 3:11 – 5:32

- Different organisms encountered in different areas of GI tract

- Intra-oral: streptococcus, neisseria, peptostreptococcus, intra-oral anaerobes

- Esophagus: streptococcus, peptostreptococcus, candida species

o Include anti-fungal coverage with esophageal perforation

- Stomach: anaerobes, gram negatives, consider H. pylori

o Low pH limited colonization

- Biliary tree: gram negatives, enterococcus, anaerobes

- Small bowel: gram negative, enterococcus, clostridium, bacteriodes, candida

- Colon: enterococcus

Biliary Tract 5:33 – 8:04

- Community acquired cholecystitis or cholangitis with mild symptoms ertapenem OR

fluoroquinolone + metronidazole

- Severe symptoms or immunocompromised individual with cholecystitis or cholangitis start

on piperacillin/tazobactam OR (ciprofloxacin or aztreonam) + metronidazole for patients with

penicillin allergy

o May include vancomycin for gram positive coverage if using ciprofloxacin or

aztreonam although may not need it for community acquired infections

- Acute cholangitis piperacillin/tazobactam OR (ciprofloxacin or aztreonam) + metronidazole

for patients with penicillin allergy

o Consider patient may have biliary enteric anastomosis

o Consider relieving pressure in biliary tract with percutaneous biliary drains because

pressure is pushing bacteria into blood stream

- Health care acquired biliary infection same as above

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Peritonitis 8:05 – 21:57

- Primary, secondary, vs. tertiary peritonitis:

o Primary = spontaneous infection of peritoneal cavity; eg. ascites, liver failure

o Secondary = infection of peritoneal cavity due to spillage of organs into the

peritoneum

Usually gastric, small bowel, or colon perforation

o Tertiary = recurrent infection of peritoneal cavity following an episode of secondary

peritonitis

Eg. had fistula form, dusky bowel, evidence of abscess in abdomen

Concern about colonization with resistant organisms

- Patients at high risk for failure to gain source control:

o Delay in intervention (not gone to OR within 24 hours)

o Advanced age

o High severity of illness APACHE-II score > 15

o Comorbidities

o High degree of organ dysfunction

o Low albumin

o Poor nutritional status

o Degree of peritoneal involvement

o Presence of malignancy

- Questions to consider:

o What did it look like? What did the surgical team report/find?

o Were cultures sent?

o Did the surgeons feel like they got source control?

o Are there drains in place?

o Did the patient come from home?

o Did they have recent antibiotic exposure?

o How sick is the patient now?

o Do they have any indwelling hardware?

- Mild-to moderate community acquired intra-abdominal infections ertapenem OR (3rd

generation cephalosporin or fluoroquinolone) + metronidazole

o Eg. patient came in for EGD and had complication with procedure

- Severely ill or high-risk community acquired intra-abdominal infections

piperacillin/tazobactam OR cefepime + metronidazole ± vancomycin if mild allergic reaction

to penicillin OR (ciprofloxacin or aztreonam) + metronidazole + vancomycin if severe

anaphylaxis to penicillins

o Eg. patient presenting with sepsis or septic shock make sure don’t miss anything

These patients have large volume of distribution ertapenem or ceftriaxone

don’t have huge volumes of distribution and short half-life

- Infectious Diseases Society of America (IDSA) recommend against empiric coverage for MRSA,

VRE, candida for KNOWN abdominal infection with caveats:

o MRSA should be started if superficial infection, possible for surgical wound to be

involved, patient has mesh or foreign bodies in place

Nasal swab screen if negative, patient has <2% risk for MRSA infection

o Anti-fungal should be started if esophageal perforation

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Consider fluconazole as prophylaxis for invasive fungal infection

- Duration of therapy guided by how rapid source control is obtained

o Eg. trauma patient 24 to 48 hours of peri-operative antibiotics IF patient is fine

clinically and stable without signs of sepsis or positive blood cultures

o Eg frank contamination of peritoneal cavity or source control not readily contained

(12-24 hours from time probable perforation to control) treat for 4 days after

obtaining source control

If patient is worsening, consider different source of infection or lack of source

control

Pneumonia 21:58 – 29:17

Community Acquired Pneumonia 21:58 – 25:28

- Community acquired pneumonia = pneumonia <48 hours within presentation to hospital

o In hospitalized patients without risk factors for pseudomonas ceftriaxone +

azithromycin OR moxifloxacin if severe penicillin allergy

o In patients with risk for pseudomonas cefepime + azithromycin OR aztreonam +

moxifloxacin if severe penicillin allergy

Narrow coverage if pseudomonas not present on culture

- Risk factors for pseudomonas:

o History of bronchiectasis

o Recent prolonged hospital stay >7 days

o Debilitated nursing home resident

o Mechanically ventilated for >48 hours

o Patients recently on broad spectrum antibiotics

o Patients who are immunocompromised (eg. solid organ transplantation,

hematological malignancy, bone marrow transplantation, chemotherapy,

corticosteroid use)

Corticosteroid use patients on greater than equivalence of prednisone

20mg for more than 3 weeks

- MRSA coverage concern even for patients from community

o Decision based on rates of MRSA seen in institution

o Empiric coverage for:

Patients known to be colonized

Immunocompromised

Necrotizing pneumonia with cavitation especially if preceding influenza

- Duration of therapy:

o Community acquired pneumonia 5 days

If immunocompromised or have structural lung disease 7 days

Poor clinical response, initial inappropriate therapy, severely

immunocompromised 10 to 14 days

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Hospital Acquired Pneumonia 25:29 – 29:17

- Risk factors for multidrug resistant ventilator associated pneumonia (VAP):

o Prior IV antibiotic use within 90 days

o Septic shock at the time of VAP

o ARDS preceding VAP

o 5 or more days of hospitalization prior to VAP

o Acute renal replacement therapy prior to VAP

- Risk factors for multidrug resistant hospital associated pneumonia (HAP):

o Prior IV antibiotic use within 90 days

- Worried about more resistant organisms including pseudomonas and MRSA

- Therapy options:

o Anti-pseudomonas penicillin (eg. piperacillin/tazobactam) or cephalosporin (eg.

cefepime or ceftazidime) OR

o Carbapenem not first line, but if patient has history of multi-drug resistant gram

negative infection OR

o Monobactam (eg. aztreonam)

o AND agent with gram positive activity and MRSA coverage (eg. vancomycin or

linezolid)

- Double coverage gram negative based on institution resistance rates

o If pseudomonas infections have >10% resistance add fluoroquinolone or

aminoglycoside

- Colonizing organisms that don’t generally need treatment: enterococcus, candida species

- Duration of therapy:

o Usually 7 days

If symptoms persist, consider alternative source or bronchoscopy with

quantitative cultures

o In patients with VAP with associated MRSA bacteremia treat for AT LEAST 14 days

after ruling out seeding of other sites

Urinary Tract Infections 29:18 – 33:21

- Consider whether patients have catheter associated UTI or asymptomatic bacteriuria

o Urinalysis and urine culture required for diagnosing catheter associated UTIs

- Asymptomatic bacteriuria = positive urine culture with no signs or symptoms of infection

o No antibiotics indicated unless patient is pregnant, post renal transplant, about to

undergo urologic procedure, or neutropenic

o Treatment is remove catheter

If can’t remove, continue to monitor patient until see signs and symptoms of

infection

- Catheter associated UTI = pyuria, positive urine culture, and have signs/symptoms of infection

o Signs and symptoms: fever and rigors with no other source, new onset

delirium/malaise/lethargy, suprapubic or flank pain

o Pyuria is > 5 to 10 WBC per high powered field

o Urine culture is >1000 colony forming units per mL

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o Treatment:

Stable, without evidence of upper tract disease remove catheter and

consider only monitoring

Without evidence of upper tract disease, but cystitis ceftriaxone OR

ciprofloxacin if severe penicillin allergy

Severely ill or with evidence of upper tract disease or hospitalization > 48 hrs

anti-pseudomonas cephalosporin (eg. cefepime) OR aztreonam if severe

penicillin allergy

o Upper tract disease = involvement of kidneys more systemic signs of infection

(fever, elevated WBC), rigors, urosepsis, etc.

o Duration of therapy 7 days

Case Example 33:22 – 38:00

- Part 1: 58 year old woman with ulcerative colitis presenting with worsening abdo pain despite

being on 5 days of antibiotics. CT scan shows free air. Surgery is called and she is brought to

the OR where she has lysis of adhesions, hemicolectomy. She ends up in the ICU with

discontinuation of bowel and an open abdomen. She is sedated.

- Next steps/questions:

o What did it look like? Was source control obtained?

Duration of therapy dependent on whether or not source control was

obtained, but wouldn’t change empiric therapy

o If found perforated ileus or small bowel with gross fecal contamination were

peritoneal cultures obtained

- Part 2: No drains were placed. She has a wound vac on. Surgeons will have to take her back

for further wash up tomorrow. She is hemodynamically unstable. She is febrile with a WBC of

25.

- Next steps/questions:

o What antibiotics patient received at home?

o Does she have any drug allergies?

- Part 3: She was on ciprofloxacin and metronidazole at home.

- Next steps:

o Would choose another antibiotic because resistance comes pretty quickly for patients

receiving fluoroquinolones.

o Make sure she doesn’t have severe penicillin allergy. If she doesn’t, start with

piperacillin/tazobactam and add empiric vancomycin until sort out what is doing on.

o If she had a life threatening penicillin allergy, avoid all beta-lactams. Use aztreonam

and metronidazole for gram negative and anaerobic coverage as well as vancomycin

for gram positive coverage. Because of her high severity of illness, add

aminoglycoside.

o If she had a mild penicillin allergy, would re-challenge her with cefepime. Also include

metronidazole and vancomycin.

o Once source control is in place and on appropriate antibiotic coverage based on

cultures, 4 days of antibiotics POST source control is appropriate.

#How do you handle intraabdominal infections, pneumonia, or bladder infections in the ICU?

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