Postoperative Issues Flashcards
Initial steps in workup of post-operative fever
- CXR
- Urinalysis
- Urine culture
- Blood culture
5 W’s of Post-Op Fever
- Wind
- Water
- Walking
- Wound
- Wonder drugs
Fever during surgery is almost certainly . . .
. . . drug induced, SPECIFICALLY malignant hyperthermia
Malignant hyperthermia: During surgery. Give high flow O2, dantrolene, cool off. Ppx is FHx screening.
Drugs that cause malignant hyperthermia
- Gas anesthetics except nitrous oxide (basically the fluranes are the most important cause)
- Succinylcholine
- Halothane
- Ether
Fever immediately after surgery
- Likely due to bacteremia from intraoperative infection, especially if you are doing surgery on an inflamed organ or the bowel.
- Diagnose: blood culture
- Treatment: Broad spectrum abx (often vancomycin + pip-tazo)
- Ppx: Maintain sterile field, avoid unncessary interference with bowel
Fever on POD#1
- Most likely to be atelectasis
- Diagnosis: Must rule out pneumonia by CXR
- Treatment: If CXR consistent w/ atelectasis, incentive spirometry and get them walking out of bed.
- Ppx: Have the patient do the above anyway after surgery, as soon as they can.
Fever on POD#2
- Most likely to be pneumonia
- Dx: Fever, cough, consolidation on CXR
- Tx: Broad spectrum abx (vancomycin + pip-tazo)
- Ppx: Incentive spirometry and out of bed
Fever on POD#3
- Most likely to be UTI
- Dx: Urinalysis, urine culture
- Note: If you see WBC casts, likely to be pyelonephritis which they had prior to going to surgery.
- Tx: Abx targeting UTIs
- Ppx: Take Foley out as soon as possible
Fever on POD#5
- Most likely to be DVT / PE
- Less likely, thrombophlebitis
- Often circumference of one leg >2 cm larger than the other
- Dx: Ultrasound of bilateral lower extremities
- Tx: Heparin bridge to warfarin (NOACs and heparin variants also possibilities)
- Ppx: LMWH (hold day of surgery, then resume), OOB
Fever on POD#7
- Most likely to be cellulitis
- Dx: Ultrasound to rule out abscess
- Tx: Abx for cellulitis
- Ppx: Maintain sterile field, keep wound clean post-operatively
Fever on POD#10-14
- Most likely to be an abscess
- Dx: Ultrasound (or CT)
- Tx: Abx, return to OR for incision and drainage
- Ppx: Sterile field, keep would clean post-op
Basically everyone with post-operative chest pain deserves which diagnostic procedures (irrespective of risk factors)
- For MI:
- EKG
- Troponin and CK
- For PE:
- Lower extremity ultrasounds
- Spiral CT
Hurricane mnemonic for post-op fevers
“First, the Wind then the Rain (Water) then you run (Walk) then you trip and fall (Wound), and you Wonder what happened to get the abscess”
Ascending odd #s plus 10 for the abscess:
POD#1 3 5 7 10
Post-surgical altered mental status
- Electrolyte derangements
- Na
- Ca
- If elderly, consider sundowning
- Treat w/ atypical antipsychotics
- Hypoxemia
- PE
- Atelectasis
- ARDS (will be in context of prolonged intubation, complicated surgery, lots of fluids, etc. These patients will need to be intubated and receive high oxygen, PEEP)
-
Delirium tremens
- HTN, tachycardia. Then tremors (~48-72 hr). Then seizures.
- Treat w/ benzodiazepines (diazepam specifically)
Which benzo is best for delirium tremens and why?
Diazepam, because it is readily absorbed, has a long halflife, and self-tapers
General management of inpatient alcohol withdrawal
- Diazepam is first-line (or lorazepam), but phenobarbital is also an excellent choice (probably better, but RCTs don’t exist yet). Can be given together if necessary.
- Always give IV thiamine too, just in case. A lot. Over several days.
- If mild, BAL > 400, no risk factors or prior history, can send home on gabapentin with followup instead of inpatient management.
Postoperative oliguria
- Normal urine output: 0.5 cc/kg/hr
-
Is there an urge to void?
- Yes: Obstructive picture. Do bladder scan or in-and-out cath (not a Foley). Usually due to anesthesia-induced neurogenic bladder, which is self-limited.
-
No: Might be renal failure. Look at urinary output. If there is truly no output, Foley is likely kinked. If there is some output but it is minimal, this is likely true renal disease.
- Give 500 cc fluid bolus challenge. If urine output increases, you are good, give more fluid. If they don’t, there is intrinsic renal disease.
Post-operative abdominal distension
-
Ileus
- Pathology: Functional
- Presentation: POD#1 or 2, no stool or flatus
- Dx: KUB showing dilated large and small bowel
- Tx: Fluids, potassium, OOB
-
Obstruction
- Pathology: Obstructive
- Presentation: POD#5, still no stool or flatus
- Dx: KUB showing either small bowel obstruction (dilation proximal, compression distal), OR large bowel obstruction (normal small bowel, dilation proximal, compression distal).
- Tx: Repeat surgery to destroy adhesions
-
Ogilvie syndrome
- Pathology: Functional
- Presentation: POD#5, still no stool or flatus, elderly patient
- Dx: KUB showing ileus of colon (complete distension of colon, NO distal area is spared)
- Tx: Decompression (rectal tube), stigmine if rectal tube fails. May need colonoscopy to rule out cancer.
Dehiscence
Failure of the fascia.
Wound is not open, but underneath the fascial planes are not closed well. Will result in a hernia when the wound heals.
Presents w/ salmon colored serosanguinous drainage. May be able to feel loss of integrity of abdominal wall on exam.
Dx: Clinical
Tx: No straining, use abdominal binder to prevent evisceration. Elective reoperation to close the hernia.
Evisceration
Failure of fascia AND skin.
Loops of bowel popping out of skin. Surgical emergency.
Dx: Clinical
Tx: Apply warm saline dressings immediately, then emergent surgery. NEVER attempt to reduce. This will result in bacterial peritonitis.
Ppx: Don’t strain, don’t get OOB too early
FETID (Fistula mnemonic)
- Foreign body
- Epithelialization
- Tumor
- Irradiation/Inflamed/Inflammatory bowel (Crohn’s)
- Distal obstruction
Fistulas
Dx: Clinical
Tx: Resect fistula. But, may need to divert fistula into otomy, fix ulderlying cause, then reconnect.
While malignant hyperthermia is the #1 concern for intraoperative fever, a broader differential includes. . .
- Febrile nonhemolytic transfusion reaction
- Thyrotoxic crisis
- Anticholinergic syndrome
- Neuroleptic malignant syndrome
- An infection acquired prior to surgery (unlikely, but does happen sometimes)
Fever >1 month after operation
- Surgical site infection by indolent organisms (coagulase negative staphylococci: Staph epidermidis, Staph hominis)
- Delayed cellulitis
- Viral infections acquired from perioperative blood product transfusion (hepatitis viridae, CMV, HIV)
- Infective endocarditis
Most surgical site infections occuring within 1 week of surgery are due to one of these two organisms:
- Streptococcus pyogenes
- Clostridium perfringens
Quick ddx for apparent nosocomial pneumonia
- True nosocomial pneumonia
- Atelectasis
- Aspiration pneumonia
- Ventilator-associated pneumonia
Most common etiologies of aspiration pneumonia, features, and treatment
- Basically caused by mixed anaerobes:
- Klebsiella
- Fusobacteria
- Peptostreptococcus
- Bacteroides
- Risk factors for aspiration present
- Halitosis/foul smelling sputum
- Always consider aspiration pneumonitis (chemical irritation) as component or as ddx
- Tx: If secondary to extubation, re-intubate. Abx not routinely recommended unless abscess is present. If treatment is indicated, use metronidazole + amoxicillin and consider aspiration.
Ventilator-associated pneumonia
- Often caused by P. aeruginosa, sometimes MRSA
- Tx: Vancomycin OR Linezolid plus one beta lactam that covers pseudomonas and pneumococci plus another non-beta lactam antipseudomonal agent, duration 7 days. Also give fluids, mucolytics, antitussives, antipyretics.
- Empiric therapy for ventilator-associated tracheobronchitis is not routinely recommended
- Tx: Vancomycin OR Linezolid plus one beta lactam that covers pseudomonas and pneumococci plus another non-beta lactam antipseudomonal agent, duration 7 days. Also give fluids, mucolytics, antitussives, antipyretics.
Pneumonia patients with structural lung disease or who otherwise have high risk for mortality should receive. . .
. . . double antipseudomonal coverage
Lung abscess
- Risk factors: Preexisting pneumonia (esp. aspiration), altered level of consciousness, immunocompromise, bronchial obstruction
- Pathology: Often polymicrobial oral and gastric anaerobes (Peptosreptococcus, Prevotella, Bacteroides, Fusobacterium). Less commonly monomicrobial S. aureus, K. pneumoniae, GAS, S. anginosus.
- Features: PNA features, indolent progression, hemoptysis, foul-smelling sputum, B symptoms
- Dx: CXR or CT showing irregular cavity w/ air fluid level that is dependent (changes with different body pos)
- Tx: Attempt Abx first w/ anerobe coverage (clindamycin, amp-sulbactam, carbapenems). If this fails, percutaneous drainage or surgical excision (segmentectomy, lobectomy)
Advantages of enteral over parenteral feeding
- Prevents mucosal atrophy by stimulating gut motility
- Lower risk of bloodstream infection
- Less frequent metabolic complications
Basic rule of thumb for nutrition
Oral before enteral
Enteral before parenteral
Metabolic complications of enteral and parenteral feeding
- Refeeding syndrome
- Hyperglycemia
- Hyperlipidemia
- Acalculous cholecystitis
- Gallstone disease
- NAFLD
- Renal damage
- Bone demineralization
Refeeding syndrome
Condition caused by rapid reinitiation of normal nutrition in a chronically malnourished patient (e.g., patients with anorexia nervosa). Caused by a sudden shift from a catabolic to an anabolic state and massive release of insulin, which causes severe electrolyte imbalances (e.g., hypophosphatemia, hypokalemia, hypomagnesemia) and fluid retention.
Clinical features include edema, cardiac arrhythmias, seizures, and ataxia. Management involves close monitoring of electrolyte levels with repletion and slow reintroduction of normal nutrition.
In someone with normal coagulation labs and platelets, __ is the most common cause of post-surgical wound site bleeding within 24 hours.
In someone with normal coagulation labs and platelets, insufficient mechanical hemostasis is the most common cause of post-surgical wound site bleeding within 24 hours.
Obese patients who undergo bariatric surgery frequently develop temporary. . . .
. . . hypoxemia
While the pathophysiology behind this is not completely understood, atelectasis-associated ventilation-perfusion mismatch is likely to play a role
When do you use a percutaneous endoscopic gastrotomy tube vs nasogastric tube for enteral feeding?
- You use a PEG when you expect the patient to need enteral nutrition long-term.
- Temporary routes such as nasogastric or nasoenteric tubes often fail with long-term use because of clogging and inadvertent dislodgement.
- However, for the short term, a PEG tube would be too invasive in a patient with a potentially reversible condition.
Persistent secondary peritonitis
- Clinical picture of post-operative fever
- On CT: inflammatory changes in the abdominal cavity without abscesses
- Can be the result of inappropriate or inadequate antimicrobial therapy, which can be addressed with additional antimicrobial therapy or modification of antimicrobial regimen.
Superficial surgical site infection
- Surigal site infection above the fascial layer
- Treated primarily w/ wound exploration and drainage
- Add abx if >2 cm cellulitis is present or if patient is immunocompromised
Deep surgical site infection
- Infections of the surgical site that involve the fascia and/or musculature
- Must have CT to rule-out involvement of the deep surgical space
Deep surgical space infection
- Post-operative infection involving cavities beneath the fascia – namely the abdominal and thoracic cavities
- In post-abdominal surgery, this may include secondary peritonitis, tertiary peritonitis, or deep surgical space abscess
Secondary peritonitis
- Often result of spillage of microbial organisms into the peritoneal cavity following visceral perforation
- Persistence of this infection can be the result of the microbial inoculum volume, the inhibitory and synergistic effects of a polymicrobial environment, and insufficient host response
- Recurrence or persistence of this process can be due to insufficient antimicrobial therapy or insufficient control of contamination process
Tertiary peritonitis
- Patients who fail to recover from intra-abdominal infections despite surgical and/or antimicrobial therapy.
- Often caused by diminished host peritoneal immune response and involves typically non-virulent, opportunistic organisms:
- Staphylococcis epidermidis
- Enterococcus faecalis
- Candida
- Treat w/ additional and prolonged antibiotic therapy
Pre-emptive antibiotic therapy
- Administration of antimicrobials when an innoculation event is though to have occurred during surgery – such as when there is GI content spillage
- In these situations, broad spectrum abx should be utilized intitially. As patients improve clinically and following microbiologic susceptibility testing, treatment can be narrowed.
Fever in a post-operative patient is __ until proven otherwise
Fever in a post-operative patient is infectious until proven otherwise
Apart from inoculum size, ___ is the most important factor in extent of infection following GI perforation.
Apart from inoculum size, location is the most important factor in extent of infection following GI perforation.
The colon has quantitatively more and more diverse (aerobes and anerobes) bacteria than the stomach (aerobes only) or duodenum!
Treatment goals for secondary peritonitis
- Eliminate the source of microbial spillage (appendectomy for appendix rupture or closure for perforated duodenal ulcer)
- Early initiation and broad spectrum for preemptive antibiotics
Dual agent and Single agent antibiotic regimens for secondary peritonitis
- Dual agent:
- 2nd or 3rd gen cephalosporine + metronidazole or clindamycin
- Fluoroquinolone + metronidazole or clindamycin
- Aminoglycoside + metronidazole or clindamycin (use in caution in older patients, patients with renal disease)
- Single agent:
- For mild-moderate cases, like ruptured appendix in otherwise healthy young person: cefoxitin, cefotetan, ceftriaxone, or amp-sulbactam
- For severe infections or infections in immunocompromised hosts: meropenem, ertapenem, tigecycline, pip-tazo
In a post-abdominal surgery patient who presents with signs suggestive of perforation, the first step is to. . .
. . . get a CT scan before you consider operating again.
Postoperative small bowel loop obstruction from evisceration and incarceration
- Will present with focal tenderness, severe nausea, vomiting in postoperative period
- Dx with CT scan
- Tx:
- DO NOT attempt to reduce if you think there is SBO (nausea/vomiting are involved)
- Rather, these patients will require re-operation, intraoperative reduction of herniated tissue, and re-closure of the wound site
Prolonged dysfunction of the GI tract following surgery usually indicates . . .
. . . the presence of intra-abdominal infectious complications
Early vs Late dehiscence
-
Early dehiscence
- Profuse serosanguinous drainage, possible “popping” sensation or bulge during Valsalva maneuvers
- 4–14 days after surgery
- Surgical emergency: Could lead to organ evisceration. Mortality rate is 10%.
-
Late dehiscence:
- Incisional hernia
Incisional hernia
- Herniation of intraabdominal contents through an abdominal wall defect created during a previous abdominal surgery.
- Risk factors: Wound dehiscence, upper midline laporotomy incision, postoperative wound infection, poor wound healing, emergent abdominal surgery
- 75% of cases in first 3 years following surgery
- Treatment:
- Conservative if: asmyptomatic with wide neck, patients with high anesthetic risk
- Surgery if: symptomatic/complicated hernias or those with a narrow neck
- Complications: 30% recurrence rate following reduction.
Postoperative ileus
- Common due to anesthesia, analgesia, handling of intestines and mesentery during surgery
- If it lasts more than 3-5 days, evaluation should be performed to rule out mechanical obstruction
The first step in post-surgery sepsis is always. . .
. . . debridement
If there is anything to debride, debride it.
Then, antibiotics: vancomycin and pip-tazo are a broad combination.
Heparin induced thrombocytopenia
- Typically occurs within 5–10 days of heparin initiation and leads to thromboembolic complications.
- Platelets will be low – this is a key differentiating factor from typical post-surgical thrombosis, as the timeframe is often very similar or the same
- Treat with cessation of heparin products and switching to NOAC like argatroban
Treatment for erysipelas
- No systemic symptoms: Oral cephalexin
- Systemic symptoms (fever): IV cefazolin
Tinea as a risk factor for dermal infection
Tinea pedis compromises the integrity of the skin, allowing other microorganisms such as Streptococcus pyogenes and Staphylococcus aureus to enter and cause infections like cellulitis
Treatment of postoperative cellulitis
- If there is any fluctuant swelling, the first step is incision and drainage of abscess.
- Nonpurulent: Oral cephalosporin
- Purulent: Vancomycin (we cover MRSA for purulent)
Empiric post-operative sepsis treatment
Vancomycin + cefepime
In a patient with BPH, ___ may occur following Foley catheterization
In a patient with BPH, bladder outlet obstruction may occur following Foley catheterization
Abdominal surgery indications with highest risk of DVT
Ulcerative colitis > Crohn’s > Colorectal malignancy
Enterocutaneous fistula
- Often occur as a complication of pancreatectomy after 10-14 days
- Pres: Afebrile, wound draining small amounts of brown-green fluid.
- Dx: Clinical. Electrolye abnormalities may be present.
- Tx: Conservative management with TPN and ostomy bag for 5-6 weeks, as they often close spontaneously. POs are contraindicated. If it does not close on its own, it should be surgically resected and repaired.
Post-operative AKI
- If, following surgery, a patient does has oliguria or anuria:
- Start w/ bladder scan to diagnose urinary retention (ie, if volume > 400 mL)
- If positive, catheterize
Abdominal compartment syndrome
- Etiology: Intra-abdominal pressure > 20 mmHg
- Risk factors: Prolonged abdominal surgery, large IV fluid and/or blood product resuscitation, AAA rupture
- Presentation: Hypotension from reduced right heart preload, pre-renal AKI, reactive tachycardia
- Often presents as pre-renal AKI pattern in a patient who has received LOTS of fluids already and probably isn’t dehydrated
- Dx: IAP > 20 mmHg. However, most of the time this is a clinical diagnosis.
- Tx: Abdominal decompression by laporotomy and temporary plastic covering
Pelvic dissection, including proctectomy, may cause __ in young women
Pelvic dissection, including proctectomy, may cause infertility in young women
Due to formation of fibrous bands and chronic pelvic inflammation
Enterocutaneous fistula output
-
Fistula output volume affects fluid/electrolyte and nutritional status of the patient
- < 200 mL/day is low risk
- > 500 mL/day is high risk
- Electrolyte status and nutritional status should be assessed and stabilized before considering definitive closure of an enterocutaneous fistula
“Hostile abdomen”
- This is a time period where you want to avoid reoperation
- Between ~7-28 days postop following a major abdominal procedure
- Characterized by a period of inflammatory changes, granulation tissue, and fibrosis that makes surgery difficult, bloody, and high risk
- Increased risk of hemorrhage
- Increased risk of intestinal perforation
- Increased risk of post-op complications (fistulas, etc)
CDC surgical wound classifications
- Class I: Clean
- Class II: Clean-contaminated
- Class III: Contaminated
- Class IV: Dirty or infected
Vitamin A in wound healing
Necessary for several components
Vitamin A deficiency causes impaired fibroplasia, collagen synthesis, collagen cross-linking, and epithelialization
Vitamin B6 in wound healing
Thiamine deficiency causes impaired collagen cross-linking
Open abdomen
- Abdomens with large fascial defects that are not closable by approximation
- Occurs in the context of repeat abdominal surgeries in short succession. Often absorbable meshes are put in place and skin is grafted over, but there is still no fascial seal.
- Can help prevent by avoiding excessive fluid administration.
- High risk for enterocutaneous fistulas
- Require reconstruction by placement of prosthesis or component separation
Incisional hernia grade and recommendations
As a general rule, repair of a fascial defect greater than ___ in diameter is associated with a high recurrence rate, and therefore requires ___.
As a general rule, repair of a fascial defect greater than > 2 cm in diameter is associated with a high recurrence rate, and therefore requires placement of prosthetic material, biologic material, or component separation.
An infected surgical site wound has a high risk of developing ___
An infected surgical site wound has a high risk of developing an incisional hernia.
Problem with using braided, nonabsorbable suture
Tends to trap tissue debris, and so it can prolong or worsen infection if infection is already present
So the long and short is, don’t use it on infected wounds
Instead, you should use absorbable suture for infected wounds.
Optimal running suture length : wound length ratio
4:1
This produces the right amount of tension to close the wound without excess tension that causes problems healing
Community acquired vs hospital acquired MRSA
They are genetically and phenotypically different.
Community acquired is more dangerous. It produces Panton-Valentine leucocidin toxin, which kills white blood cells.
Community-acquired MRSA can cause necrotizing infections more readily than hospital-acquired.
Patients that may not present with “classic” soft tissue infection signs
-
Immunocompromised
- HIV
- Radiation/chemo
- Immunosuppressive medications
- Cirrhosis
- Alcoholism
Daptomycin
Lipopeptide antibiotic
Quite effective in treatment of soft-tissue infections, including MRSA
Pain out of proportion to skin findings in cutaneous infection
Highly suspicious for microvascular thrombosis and tissue ischemia
Often associated with necrotizing soft tissue infection
Fournier’s Gangrene
- Rapidly progressive soft tissue infection of the perineal, scrotal, and penis area in males
- Process may occur less commonly in the perineum in females
- Can lead to skin necrosis, sepsis, and death within hours or days if unrecognized
- Polymicrobial synergistic infection leading to sepsis and multiple organ dysfunction
- Treat w/ broad spectrum antibiotics against aerobic and anerobic organisms, debridement
Clinical manifestations and treatment of necrotizing soft tissue infection
If you suspect a necrotizing skin infection, the best way to confirm is by. . .
. . . CT scan to assess for calcifications or gas
Panton-Valentine leucocidin mechanism
Pore-forming toxin
Line between secondary and tertiary peritonitis
48 hours
If it persists > 48 hours, it is tertiary
Suppurative parotitis
Post-op fever timeline (uworld)
