Describe the possible consequences of prolonged anesthesia
Manage patients scheduled for prolonged anesthesia
Background
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 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
Immunosuppression and increased susceptibility to infections
Increased risk of human error due to fatigue
Management
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.