Perioperative management

Perioperative management consists of preoperative patient evaluation as well as intraoperative and postoperative patient monitoring and care. The operative risks are assessed prior to surgery by considering patient history, physically examining the patient, and conducting any tests deemed necessary. Preoperative adjustments are made based on the assessment findings (e.g., stopping, replacing, or temporarily administering certain drugs by another route). The specialist responsible is legally obliged to disclose all relevant information regarding the procedure to the patient. Perioperative antibiotic prophylaxis is recommended in many types of surgery in order to prevent postoperative wound infections. The main goals in the postoperative phase are early recovery and preventing complications or, if complications occur, diagnosing and treating them as early as possible.

1. Obtain surgical consent.
2. Obtain a thorough medical history; and perform a physical examination.
3. Specific diagnostics
   • Laboratory tests if indicated (see table below)
   • Preoperative cardiac assessment
   • Preoperative pulmonary assessment
   • Preoperative nutritional status assessment

Preoperative tests should be ordered only if they are indicated.

• Patients should be asked about their smoking history; and discontinue smoking 8 weeks prior to surgery.

References:^[1][2]

• Indications for preoperative LFTs
  • Symptoms of liver disease (e.g., jaundice, hepatomegaly)
  • In asymptomatic individuals, if the patient has chronic liver disease
• Risk assessment
  • Patients with acute hepatitis: Elective surgery is contraindicated until LFTs improve.
  • Chronic liver disease
    • Child class B and A, or a MELD score < 15: Surgery may be performed after treating encephalopathy, coagulopathy, and ascites.
    • Child class C or MELD score > 15: Elective surgery is contraindicated until the Child or MELD score improves.

• Clinical indicators of severe protein energy malnutrition (> 2 of the following)
  • Body mass index <18.5
  • Recent weight loss
  • Bedridden or otherwise significantly reduced functional capacity
  • Obvious significant muscle wasting; loss of subcutaneous fat
• Laboratory tests that can be used to assess nutritional status include:
  • Lymphocyte count
  • Albumin and total serum protein
  • Cholesterol
• If a patient is found to be malnourished: Specialized nutritional support (preferably enteral nutrition) is given prior to surgery to optimize nutritional status.

All preoperative patients should have their nutritional status assessed, with those at greater risk or with signs of malnutrition receiving a formal nutritional assessment.

Malnutrition has been associated with a greater risk of postoperative complications, including increased overall morbidity and mortality, longer hospital stays, increased risk of infection, delayed wound healing, and increased rate of ICU admissions!

Antianginal medications, antiepileptics, statins, antihypertensive drugs (except ACE inhibitors, ARBs, and diuretics), and most neuroleptics (except lithium) should be continued on the day of surgery.
References:^[3][4][5][6]

• Discontinue certain medications (see discontinuation of medication prior to surgery above).
• Fasting
  • 8 hours before surgery: no meat or fried, fatty food
  • 6 hours before surgery: no milk or solid food
    • Breast-fed infants: no breast milk 4 hours before surgery
  • 2 hours before surgery: nil per os (NPO)

The preoperative fasting recommendations can be remembered with the “2, 4, 6, 8 rule”!

• Anesthesia (see general anesthesia and regional anesthesia)
• Perioperative antibiotic prophylaxis
  • Aim: to reduce the incidence of postoperative surgical site infections; (most commonly caused by S. aureus)
  • Antibiotic of choice
    • First-line treatment: intravenous cefazolin
      • In patients with beta-lactam allergy: clindamycin or vancomycin
    • Add intravenous metronidazole for:
      • Patient with small intestinal obstruction
      • Appendectomy
      • Colorectal surgery

References:^[7][8]

• Monitor blood pressure, pulse, oxygen saturation, temperature, urine output, and surgical drain output.
  • If a patient has a urine output < 0.5 mL/kg/hour for > 6 hours: Check catheter patency.
• Supportive care in intubated patients
• Pain management according to WHO analgesic ladder
• Stress ulcer prophylaxis with proton pump inhibitors
• Thromboprophylaxis with low-dose LMWH or UFH before and after surgery, especially for immobile, bedridden patients
• Incentive spirometry and breathing exercises in order to prevent lung atelectasis
• Fluids: replacement of ongoing fluid loss and maintenance fluid therapy
• Enteral nutrition; should be started as soon as possible to prevent villous atrophy.
• Daily examination of the surgical wound
• Early mobilization

References:^[9]

• Temperature > 38°C in the postoperative period
• Etiology

The most common infectious causes of postoperative fever are surgical site infections, pneumonia, catheter-related urinary tract infections, and primary bloodstream infections. The most common noninfectious cause is febrile drug reaction.

• Diagnostics
  • Only performed to diagnose a specific cause, based on the clinical presentation and time of onset
  • Chest x-ray, blood cultures, urine cultures, and wound cultures are indicated if nosocomial infections are suspected.
• Treatment
  • Discontinue all unnecessary medications; and remove or change urinary catheters and peripheral venous lines.
  • Acetaminophen
  • Patients who are hemodynamically unstable: broad-spectrum antibiotic therapy

References:^[11]

While postoperative bleeding from the surgical wound is common (due to, e.g., infection or mechanical stress on the incision), it is important to remember that bleeding may also occur at other sites than the wound in patients with hemostatic disorders (e.g., due to central line insertion).

• Definition: infection arising within 30 days of a surgical procedure at the the site of surgical intervention
• Epidemiology
  • 15–20% of all healthcare-associated infections
  • Most common nosocomial infection among patients undergoing surgery
  • Incidence: ∼ 5% of all surgical wounds
• Etiology
  • Causative pathogens
    • During the first 4 days (uncommon)
      • Group A streptococci (GAS)
      • C. perfringens → necrotizing fasciitis
    • After 4 days; : SSI due to bacteria in the skin, genital tract, or gastrointestinal tract (e.g., S. aureus)
    • > 30 days; : SSI due to indolent organisms (e.g., coagulase-negative staphylococci)
  • Risk factors
    • Patient-related
      • Corticosteroid therapy
      • Malnutrition
      • Obesity
      • Diabetes mellitus
      • Advanced age
    • Surgical site related
      • Large incision
      • Degree of wound contamination

• Classification and clinical features

• Diagnostics
  • Leukocytosis
  • Incisional SSI: wound swab for Gram stain and wound culture
  • Organ/space SSI: imaging (e.g., CT, MRI)
• Treatment
  • Surgical therapy
    • Suture removal; , incision and drainage; , regular dressings, and daily wound inspection
    • Debridement; is indicated when there is devitalized tissue.
    • Delayed closure once the wound is no longer infected
  • Empirical antibiotic therapy
    • Indications
      • Erythema and induration extending > 5 cm from the wound edge
      • Fever > 38.5° C
      • Heart rate > 110/min
      • WBC count > 12,000 cells/mm³
    • Antibiotic of choice
      • SSI in a clean wound over the trunk, head and neck, or limb:
        • Low risk of MRSA: cefazolin
        • High risk of MRSA; , or individuals allergic to beta-lactams: vancomycin, daptomycin, or linezolid
      • SSI in a clean-contaminated wound; , or in a clean wound over the perineal region: cephalosporin and metronidazole, levofloxacin and metronidazole, or carbapenem
      • If group A streptococci or C. perfringens; is suspected: penicillin and clindamycin
  • Targeted antibiotic therapy may be initiated once results of the bacterial culture are available.
• Complications
  • Wound dehiscence
  • Secondary hemorrhage
  • Bloodstream infection → sepsis → septic shock
• Prevention
  • Optimize blood glucose levels.
  • Stop smoking one month before surgery.
  • Delay the elective procedure until all infections, even those remote from the surgical site, are treated.
  • Skin antisepsis in the operating room
  • Perioperative antibiotic prophylaxis

References:^{[12][13][14][15][16]}

Epidemiology

• Incidence
  • 30–50% among postsurgical patients in the general population
  • Up to 80% in high-risk groups
• Sex: ♀ > ♂

Differential diagnosis

• < 1 week after surgery; : self-limiting gastric or intestinal atony; , or a more severe paralytic ileus
• > 1 week after abdominal surgery; : early mechanical bowel obstruction
• See also differential diagnoses of nausea and vomiting

PONV prophylaxis

• Reduction of baseline risk:
  • Choose regional anesthesia over general anesthesia whenever possible.
  • If general anesthesia is required, avoid the use of nitrous oxide and volatile anesthetics; use a propofol infusion instead.
  • Minimize the perioperative use of opiates.
  • Adequate hydration
• Additional measures:
  • 0–1 PONV risk factors (low PONV risk; ): no antiemetic
  • 2 PONV risk factors (medium PONV risk; ): one antiemetic
  • ≥ 3 PONV risk factors (high PONV risk; ): two or more antiemetics of different classes

Treatment of PONV ^[18][19]

• Address any contributing factors (e.g., discontinue opioid analgesics, start bowel regimen).
• Use an antiemetic that was not used for prophylaxis (see antiemetics).
  • 5-HT₃ antagonists
    • Ondansetron
    • Granisetron
    • Tropisetron
  • Alternatives
    • Dexamethasone
    • Droperidol
    • Promethazine

Complications

• Prolonged hospital stay
• Increased risk of aspiration pneumonia
• Secondary hemorrhage due to retching
• Mallory Weiss syndrome

References:^[18]

• Definition: failure to void > 4 hours after surgery
• Risk factors
  • Patient-related
    • Age > 50 years
    • Male patient
    • Pre-existing obstructive urinary tract; symptoms (e.g., BPH)
    • Neurological; disease (e.g., multiple sclerosis; , diabetic neuropathy)
  • Procedure-related
    • Long duration of procedure
    • Inguinal hernia repair, gynecological, anorectal surgery, joint arthroplasty
    • Severe postoperative pain
    • Excessive administration of intravenous fluids (> 750 mL)
    • Spinal or epidural anesthesia
    • Use of sedatives; and or opioid analgesics
    • Perioperative administration of α-blockers or anticholinergics (e.g., atropine)
• Diagnostics: Bladder ultrasound; is not required but may be performed to assess the bladder volume.
• Treatment
  • If the patient is catheterized preoperatively
    • Check the catheter for kinking or blocks in the lumen.
    • If no kinking is present, consider acute kidney injury.
  • If the patient is not catheterized preoperatively
    • First-line
      • Trial of voiding
      • Adequate analgesia with NSAIDs
    • Second-line: intermittent catheterization or the placement of an indwelling catheter
• Complications
  • Acute hydronephrosis → postrenal cause of acute kidney injury
  • Urinary tract infection
  • Prolonged hospital stay → increased risk of hospital-acquired infections

Check the catheter for kinks or blockage if a catheterized patient develops signs of urinary retention (e.g., lower abdominal pain, bladder fullness).

• Risk factors
  • Open surgery
  • Excessive bowel handling during intra-abdominal surgery
  • Electrolyte imbalances (e.g., hypokalemia)
  • Use of opiates
• Pathophysiology
  • Physiologic postoperative ileus; : impaired gastrointestinal motility that occurs following surgery and resolves spontaneously within 2–3 days
  • Prolonged postoperative ileus: impaired gastrointestinal motility for > 3–5 days
• Clinical features
  • Failure to pass flatus
  • Nausea and vomiting may be present.
  • Abdominal distention may be present.
  • Absence of bowel sounds on auscultation
• Differential diagnosis: early mechanical bowel obstruction
• Management
  • Physiologic postoperative ileus
    • Conservative measures only
    • Avoid excessive fluid administration.
    • Preferential use of NSAIDs; (e.g., ketorolac) over opiates
    • Early mobilization if possible
    • Early initiation of enteral feeding if possible
    • Nasogastric tube only if abdominal distention is prominent
  • Prolonged postoperative ileus
    • See bowel obstruction.

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