Prolonged anesthesia - NYSORA

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Prolonged anesthesia

Learning objectives

  • Describe the possible consequences of prolonged anesthesia
  • Manage patients scheduled for prolonged anesthesia


  • Prolonged anesthesia is associated with an increased risk of postoperative complications
  • Careful preparation, management, and attention to detail reduce these risks

Negative effects of prolonged anesthesia

    • Accumulation of anesthetic agents leads to delayed emergence, depending of the pharmacokinetics of the agent used (e.g., isuflurane>desflurane, fentanyl>remifentanil)
    • Potential toxicity of anesthetic agents
      • Degradation of inhalational agents by CO2 absorber may lead to accumulation of toxins (e.g., sevoflurane tp compound A)
      • Inorganic fluoride production from the hepatic metabolism of sevoflurane and enflurane may be nephrotoxic in patients with chronic renal impairment
      • Prolonged exposure to nitrous oxide may result in acute vitamin B12 deficiency with megaloblastic anemia and neurological deficit
    • Impairment of gas exchange and respiratory mechanics (hypoxemia and hypercarbia secondary to slowly developing dependent atelectasis
    • The effects of anesthetic agents on renal function can lead to water and salt retention
    • Disturbances in intermediary carbohydrate metabolism promote the development of metabolic acidosis
    • Retention of anesthetic agents in the body can lead to undesired effects postoperatively
    • Decreased carbohydrate metabolism results in intraoperative hyperglycemia
    • Problems with accurate fluid and electrolyte management
    • Inadvertent perioperative hypothermia can lead to:
      • Increased wound infection
      • Surgical bleeding
      • Impaired immune function
      • Increased incidence of myocardial ischemia and infarction
      • Malignant arrhythmias
      • Postoperative shivering
    • Prolonged immobility can lead to:
  • Postoperative delirium
  • Immunosuppression and increased susceptibility to infections
  • Increased risk of human error due to fatigue


prolonged anesthesia, joint placement, traction, N2O, enflurane, desflurane, halothane, low-flow circle, temperature, invasive blood pressure, blood loss, bispectral index, tracheal tube cuff, nerve stimulator, blood gas, electrolytes, glucose, coagulation, pressure-volume loop, lung compliance, oxygen, nitrous oxide, anesthetic vapor, co2, fluid balance, central venous pressure, urine output, cardiac output, regional, sedation, total intravenous anesthesia, target-controlled anesthesia, arthralgia, eye protection, deep vein thrombosis, physiotherapy

Suggested reading

  • Pollard BJ, Kitchen, G. Handbook of Clinical Anaesthesia. Fourth Edition. CRC Press. 2018. 978-1-4987-6289-2.
  • Cheng H, Clymer JW, Po-Han Chen B, et al. Prolonged operative duration is associated with complications: a systematic review and meta-analysis. J Surg Res. 2018;229:134-144.

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