Perioperative management

Cardiac risk stratification
Revised cardiac risk index (RCRI) 1 procedure-related risk factor: intrathoracic surgery, intra-abdominal surgery, or suprainguinal vascular surgery 5 patient-related risk factors Ischemic heart disease Congestive heart failure History of stroke or TIA Creatinine > 2.0 mg/dL Insulin-dependent diabetes mellitus Poor functional capacity: patients who become breathless and/or have chest pain while climbing a flight of stairs, walking on level ground at 4 km/hr, or performing heavy work around the house
Preoperative cardiac evaluation	Indications
ECG	Patients with > 1 RCRI risk factor and one of the following: Age > 65 years COPD Peripheral vascular disease Arrhythmias
Echocardiography	Exacerbation or new onset of cardiac symptoms (e.g., dyspnea, chest pain, syncope) Patients with moderate or severe valvular regurgitation or stenosis who have not had an echocardiogram in the past year
Stress test	0–1 RCRI risk factor → < 1% risk of perioperative major cardiac event (MACE) → low-risk procedures → no stress test is required > 1 RCRI risk factor → ≥ 1% risk of perioperative MACE (e.g., MI, ventricular fibrillation, complete heart block) → elevated risk of a perioperative event If moderate or greater functional capacity: no stress test is required Unknown or poor functional capacity Patient is able to exercise: exercise stress test (e.g., exercise stress echocardiography, radionuclide myocardial perfusion imaging) Patient is unable to exercise: pharmacological stress test (e.g., dobutamine stress echocardiography, radionuclide myocardial perfusion imaging with dipyridamole, adenosine, or regadenoson)

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

Assessment	Indication for preoperative assessment
Chest x-ray	Surgeries of the head and neck, thorax, upper abdomen Clinical features and/or a history of cardiac or pulmonary disease (e.g., COPD, congestive heart failure) > 60 years ASA score > 2 Hypoalbuminemia Emergency procedures Prolonged surgeries (> 3 hours)
Pulmonary function tests	Unexplained dyspnea or exercise intolerance in patients who are about to undergo thoracic or upper abdominal surgery Patients with COPD or bronchial asthma who have not had a baseline pulmonary function test As a guide to plan lung resection FEV1 > 2.0 L and DLCO > 80%: pneumonectomy can be tolerated If the FEV1 < 2.0 L (< 80%) and DLCO < 80%, the predicted postoperative FEV and DLCO can be calculated to assess the risk. FEV1 > 1.5 L and DLCO > 60%: Lobectomy can be tolerated. FEV1 < 1.0 L: not a candidate for surgery
Cardiopulmonary exercise test	Patients with abnormal pulmonary function tests As a guide to plan lung resection

References:^[1][2][3]

• 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.
    • Exception: Liver transplantation may be performed in patients with acute fulminant hepatitis.
  • 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.
    • Exception: Liver transplantation is contraindicated in patients with a MELD score < 15.

• Definition: infection arising within 30 days of a surgical procedure at the the site of surgical intervention
  • For the following procedures, any infection arising deeper than subcutaneous tissue within 90 days of surgery is considered a surgical site infection.
    • Breast surgery,
    • Herniorrhaphy
    • Cardiac surgery, CABG, pacemaker surgery, peripheral vascular bypass surgery
    • Craniotomy, ventricular shunt
    • Open fracture reduction, hip prosthesis, knee prosthesis
• 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) → toxic shock syndrome
      • 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

Type of surgical wound	Definition	Incidence of SSI
Clean	All of the following: Noninflamed operative wound The respiratory, alimentary, genital, and urinary tracts have not been entered during surgery. Wound is closed primarily with or without a drain	1.5%
Clean-contaminated	Noninflamed operative wound The respiratory, alimentary, genital, and/or urinary tracts have been entered.	8%
Contaminated	Fresh, open, accidental wounds Inflamed operative wound without purulent drainage Clean or clean-contaminated wounds with a break in sterile technique during surgery	15%
Dirty or infected wounds	Old traumatic wounds Inflamed operative wound with purulent drainage	40%

• Classification and clinical features

Type of SSI	Incisional SSI		Organ/space SSI
	Superficial incisional SSI	Deep incisional SSI
Definition	SSI involving only the skin and subcutaneous tissue of the incision	SSI involving fascia and muscle layers at the site of the incision	SSI involving any part of the body that is deeper than the fascia or muscle layers, and was opened or manipulated during surgery
Clinical features	Purulent discharge from the incision In some cases, postoperative fever Tenderness, erythema, warm, and/or localized swelling	Purulent discharge from deep within the incision Postoperative fever Tenderness at the incision Wound dehiscence Necrotizing fasciitis: cloudy gray discharge, possible crepitus of tissue surrounding the wound	Postoperative fever Purulent discharge from a drain placed within the organ or space, or an abscess Additional signs will be present depending on the site of infection (e.g., osteomyelitis).

• 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:^{[13][14][15][16][17][18]}

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

PONV risk factors	Adults	Children
Patient-related	Female sex Past history of PONV History of motion sickness Non-smoker Age < 50 years	Age > 3 years Past history or family history of PONV
Procedure or treatment related	Volatile general anesthetics including nitrous oxide Perioperative opiate use Emetogenic procedure (laparoscopy, gynecological procedures, and cholecystectomy)	Surgery lasting ≥ 30 minutes Strabismus surgery

• 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
• 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: : Use an antiemetic that was not used for prophylaxis.
• Complications
  • Prolonged hospital stay
  • Increased risk of aspiration pneumonia
  • Secondary hemorrhage due to retching

References:^[19]

• 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.