• Clinical science

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.

General preoperative assessment

  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
Laboratory test Indication
Hemoglobin or hematocrit
  • Liver disease
  • Procedures in which severe blood loss is anticipated
  • Extremes of age
  • Clinical features of anemia
  • Clinical features or history of bleeding and/or hematopoietic disorders
Blood grouping and crossmatching
  • Procedures in which severe blood loss is anticipated
Random blood glucose
Electrolytes and creatinine
Coagulation studies
Urine analysis
  • Implantation of foreign bodies during surgery (e.g., metal implants, artificial heart valves)
  • Invasive urological surgery
  • Clinical features of urinary tract disease
Pregnancy test
  • Women of childbearing age if pregnancy would potentially alter management

Preoperative tests should be ordered only if they are indicated!

ASA physical status classification system (ASA = American Society of Anesthesiologists)
Grade Definition 30-day mortality
  • Normal healthy patient who does not smoke
  • Smokers or patients
  • Mild systemic disease (no functional limitation)
  • Severe systemic disease (functional limitation is present)
  • Severe disease that is a constant threat to life
  • Patient who is likely to die within the next 24 hours
  • Patient who has been declared brain-dead and is on cardiopulmonary support so that organs may be removed for donation

  • Emergency surgery

Preoperative cardiac assessment

Cardiac risk stratification
  • Revised cardiac risk index (RCRI)
  • 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
  • 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

Preoperative pulmonary assessment

  • 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


Preoperative hepatic assessment

  • Indications for preoperative LFTs
    • Symptoms of liver disease (e.g., jaundice, hepatomegaly)
    • In asymptomatic individuals, if the patient has chronic liver disease
  • Risk assessment

Preoperative nutritional assessment

  • Clinical indicators of severe protein energy malnutrition (> 2 of the following)
    • Body mass index <18.5
    • Recent weight loss (> 2% in 1 week, > 5% in 1 month, or > 7.5% in 3 months)
    • Bedridden or otherwise significantly reduced functional capacity
    • Obvious significant muscle wasting; loss of subcutaneous fat
    • Nutritional intake of < 50% of recommended intake for 2 weeks or more (as assessed by dietitian)
  • Laboratory tests that can be used to assess nutritional status include:
  • If a patient is found to be malnourished: Specialized nutritional support (preferably enteral nutrition) is given prior to surgery to optimize nutritional status.

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

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

Discontinuation of medication prior to surgery

Common long-term medications Recommendations
Antidiabetic drugs
  • Oral hypoglycemics
    • Metformin: discontinue 2 days before and after surgery
    • Discontinue other oral hypoglycemics on the day of surgery and postoperatively until the patient is no longer NPO.
  • Insulin
    1. Discontinue insulin on the day of surgery but administer IV intraoperatively based on the sliding scale or the variable rate infusion method.
    2. Continue insulin therapy postoperatively based on the sliding scale or a variable rate infusion method until glucose levels are stable and oral antihypoglycemics can be resumed.
Antihypertensive drugs
  • Discontinue the following antihypertensives one day before surgery and continue postoperatively:
  • Continue all other antihypertensives*
Antianginal drugs
  • Continue*
  • Continue*
Oral contraceptives
  • Discontinue 4 weeks before surgery
Psychiatric drugs
  • Continue*
Anticoagulant or antiplatelet drugs
  • Discontinue intraoperatively and resume postoperatively.
  • Short-acting NSAIDs: discontinue one week before procedure
  • Long-acting NSAIDs: discontinue 2–3 days before procedure
*During the preoperative period, necessary drugs can be administered orally up to 2 hours before anesthesia. For orally administered drugs that are to be continued intraoperatively and postoperatively, a parenteral preparation or an equivalent parenterally administered substitute is required until oral consumption can be resumed.

Antianginal medications, antiepileptics, statins, most antihypertensive drugs (except ACE inhibitors, ARBs, and diuretics), and most neuroleptics (except lithium) should be continued on the day of surgery!

Preoperative preparation

  • 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
    • 2 hours before surgery: nil per os (NPO)
    • Maintenance fluid therapy may be given if the patient has been fasting for a long period.

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


Postoperative management

Postoperative complications

Wound-related complications
General postoperative problems Postoperative cardiac complications Postoperative pulmonary complications Renal and urinary tract complications


Postoperative fever

  • Temperature > 38°C in the postoperative period
  • Etiology
Onset of fever Etiology
Infectious Non-infectious
  • Intraoperatively or within a few hours of surgery
  • Infection acquired prior to surgery
  • Within one week of surgery
  • > 1 week but < 1 month after surgery
  • > 1 month after surgery

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 a 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


Perioperative hemorrhage

Type of perioperative hemorrhage Definition Etiology
Primary hemorrhage
  • Intraoperative hemorrhage
Secondary hemorrhage < 24 hours

1–7 days

> 1 week

While bleeding due to mechanical causes and surgical site infection usually occurs from or near the surgical wound, bleeding due to hemostatic disorders can also occur at sites other than the wound (e.g., bleeding from central lines)!

Surgical site infection

Type of surgical wound Definition Incidence of SSI
  • 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%
  • Noninflamed operative wound
  • The respiratory, alimentary, genital, and/or urinary tracts have been entered.
  • 8%
  • 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
  • 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
  • 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).


Postoperative nausea and vomiting

  • Epidemiology:
    • Incidence
      • 30–50% among postsurgical patients in the general population
      • Up to 80% in high-risk groups
    • Sex: >
PONV risk factors Adults Children
  • 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)


Postoperative urinary retention

  • Definition: failure to void > 4 hours after surgery
  • Risk factors
  • Prevention
    • Perioperative administration of prazosin in high-risk patients
    • Pre-emptive catheterization if multiple risk factors are present
  • 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

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

Postoperative ileus

  • 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