post operative fever tad kim, m.d. uf surgery [email protected] (c) 682-3793; (p) 413-3222

Post Operative Fever


Tad Kim, M.D.UF Surgery

[email protected](c) 682-3793; (p) 413-3222


Overview

• Definition & Pathophysiology

• Differential Diagnosis– The five “W”– Modified approach to DDx

• Initial assessment and work-up

• Management

• Cases


Definition & Pathophysiology

• Fever is temp ≥ 38 degrees Celsius

• Manifestation of cytokine release/response– By monocyte, macrophages, endothelial cells– IL-1, IL-6, TNF-alpha, IFN-gamma– Act on the hypothalamic endothelium– Stimulate produx of PGE2 & cAMP release– cAMP acts as neurotransmitter & raises the

“set-point” => heat conservation & production


Differential Diagnosis

• The Five “W” & timing of each

• Wind (POD#1) atelectasis, pneumonia

• Water (POD#3) UTI, anastomotic leak

• Wound (POD#5) wound infex, abscess

• Walking (POD#7) DVT / PE

• Wonder-drug or What did we do?– Many drugs cause fever, ?blood transfusions,

central lines we put in (line sepsis)


Differential Diagnosis

• Five W’s are a guide for the most common• But also learn to think worst-case scenario

– “What can kill this patient if I miss the dx?”

• In general, early fever is not infectious with one critical exception: Necrotizing fasciitis or soft tissue infection

• Most early post-op fever resolves w/o tx– Simply a reaction/response to the surgery

• Fever occuring later: more likely infectious


DDx – Modified Approach

• Immediate fever – onset in OR or hrs after

• Killers: – necrotizing infection (can kill rapidly)

• Clostridium perfringens, Group A β-hemo strep• Tx: ABC, Resusc, Pen G, surgical debridement

– malignant hyperthermia• Tx: ABC, Resusc, rapid cooling, IV dantrolene

• Other: Allergic rxn (to abx) or transfusion• Look for hypotension, rash• Tx: Stop the offending agent


DDx – Modified Approach• Acute fever– within first week after surgery• In addition to five W’s, think of these:• Killers:

– necrotizing infection (within 48hrs)– anastomotic leak (classically POD# 3 to 5)

• new abd pain, distension, peritoneal signs• fever, tachycardia, hypotension

– pulmonary embolism or MI (can p/w fever)

• Other: VAP, aspiration, nosocomial infex, EtOH withdrawal (day 3), acute gout


DDx – Modified Approach

• Subacute/delayed fever – after ~5days post-op, infectious etiology is more likely– #1: Wound infection (40%)– #2: UTI (29%) especially if indwelling Foley– #3: Pneumonia (12%) if on vent or COPD– Also think of: C.dif colitis, line sepsis &

bacteremia, intra-abdominal abscess– Rarer: sinusitis, meningitis, peri-rectal

abscess, acalculous cholecystitis, parotitis– Weeks out: endocarditis, infected prostheses


Initial Assessment

• If called for fever, get to the bedside, get the nurse/flowsheet and ABC with vitals

• Obtain a history or use the AMPLE format– Type of surgery, meds or blood given, other

symptoms (rash, cough, dyspnea, chest pain, dysuria, leg swelling, painful IV site, abd pain)

• Physical:– #1 check the wound or surgical site– #2 lung sounds, heart/abd/extremity exam– #3 check IV sites, central line, Foley, tubes


Work-Up• Labs if concerned about infection:

– CBC w diff, Sputum Cx, UCx, Blood Cx x2– Lumbar puncture (if AMS, neck pain, fever)– C.dif toxin assay– STAT gram stain if suspect necrotizing infex

• Imaging:– CXR (for pneumonia)– Lower extremity venous duplex (for DVT)– CT scan (for abscess, leak; or PE protocol)– RUQ ultrasound (if suspect cholecystitis)


Management

• Remove/replace sources of infection– Foley catheter, central lines, or peripheral IV’s– Open, debride, and drain infected wounds

• Antibiotics not indicated for wound infex unless associated cellulitis

• Tylenol 10mg/kg (ped) or 650mg po x1

• If suspect pneumonia, bacteremia, UTI, sepsis – start broad spectrum antibiotics


Case 1

• 58yo man 5hrs after bilateral total knee arthroplasty. Temp of 38.7 C

• Only c/o knee pain controlled w meds

• On no antibiotics, taking home meds

• VS: Pulse 90, BP 130/70, O2 sat: 99%

• Mild serosanguinous drainage from knees

• No Foley or central lines, WBC 7 (normal)

• What do you do?


Case 1

• What do you do?– A. Urine culture– B. Blood, urine cultures & CXR– C. Blood, urine cultures & vancomycin– D. Observation only


Case 2

• 65yo obese, diabetic female 5hrs s/p open chol’y for gangrenous cholecystitis. Called with T 40.0 C, tachycardia, abd pain

• Sx: Altered mentation, abd pain

• VS: P 140, BP 88/50, O2 Sat 94%

• PE: Wound is blistered, +crepitus, sub-Q gas & dirty, dishwater drainage

• Gram stain of fluid shows gram pos rods


Case 2• What is the diagnosis?

– A. Cellulitis– B. Diffuse peritonitis– C. Necrotizing fasciitis– D. Uncomplicated post operative fever

• What is the organism on gram stain?– A. Group A strep– B. MRSA– C. Clostridium perfringens– D. Enterococcus


Case 2 Lessons• Necrotizing fasciitis

– Type I: Polymicrobial with aerobes/anaerobes usu. occurs after surgery, in DM or PVOD

– Type II: Monomicrobial 2ndary to Group A strep, Strep pyogenes

– MRSA is becoming more common for Type II

• ABC, ?intubate, 2 large IV, resuscitate• Early Pen G + Broad-spectrum antibiotics• Early surgical debridement

– Mortality is 100% with antibiotics alone


Case 3

• 61yo F w rheumatoid arthritis on methotrexate undergoes left total hip. Has Foley catheter postoperatively. Fever of 38.1 C on POD#1, Foley is removed. Then has fever of 38.5 C on POD#4.

• She has been ambulating, using incentive spirometry, O2 Sats and vitals are normal

• Wound is clean


Case 3

• What is the most likely diagnosis?– A. Deep venous thrombosis– B. Urinary tract infection– C. Superficial wound infection– D. Prosthesis infection


Take Home Points

• Know the five W’s as a rough guide for most common causes & timing

• Learn to think of what can kill the patient

• Also think: “what did we do to cause this?”

• Targeted H&P / labs / imaging to rule out the killers, then confirm most likely cause– Should have a working diagnosis before labs

• Know the dx & treatment of ‘nec fasciitis’

post operative fever tad kim, m.d. uf surgery [email protected] (c) 682-3793; (p) 413-3222

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