Advantages of TIVA

Anaesthesia has traditionally been administered by the inhalational route and this practice has persisted despite the development of better intravenous drugs and the technology to infuse them accurately and safely.

Total intravenous anaesthesia (TIVA)

• Involves the use of propofol as the hypnotic drug together with analgesic adjuncts
• The use of inhalational agents is associated with higher incidences
  • Neurobehavioral disturbances
  • Nausea and vomiting
  • Airway reactivity
  • Pain
  • In addition, is a known trigger for malignant hyperthermia and rhabdomyolysis in susceptible patients
• TIVA with target-controlled infusion (TCI) allows individual drug titration during induction (personalised anaesthesia) to reduce the risk of “over” and “under” anaesthesia
• The potential anti-cancer effects of propofol are an exciting development.

PONV

• General incidence of 30% and can rise to 80% in patients with additional risk factors
• Apfel Score
  • Predicts risk of postoperative nausea and vomiting (PONV)
  • 4 Variables
    • Gender (Female= 1)
    • Smoking Status (Smoker= 1)
    • History of motion sickness or PONV (Yes= 1)
    • Use of postoperative opioids (Yes= 1)
  • 24hour PONV risk 0= 10%, 4= 79% risk
• Propofol is an anti-emetic
  • Low dose (much lower than the dose requirement to produce sedation ~ 1/3)
  • RCT established propofol as part of multimodal strategies to reduce a patient’s risk of PONV
  • Meta-analysis showed that TIVA reduces the relative risk of PONV by 39% compared with inhalational anaesthesia
  • Consensus Guidelines promote TIVA in order to reduce baseline PONV risk
• PONV has a significant impact on postoperative care
  • Delayed discharge
  • Prevention of oral fluid and nutritional intake
  • Increased treatment costs
• Serious complications
  • Wound dehiscence
  • Anastomotic leak
  • Mechanical complications in certain surgeries
    • Upper Gastrointestinal
    • Head and Neck
• The relative importance of PONV to patients may be underestimated by health care providers
  • Surgical patients prefer to suffer pain rather than nausea
  • Surgical patients are willing to pay considerable amounts of money for an effective anti-emetic

Postoperative Pain

• Propofol reduces pain scores 24 hours after surgery with lower opioid consumption
• Enhances the inhibitory function of GABA
• Inhibits the phosphorylation of a subunit of the NMDA receptor
• Anti-oxidant and anti-inflammatory effects of propofol
• Propofol also has actions on other receptors that play a role in pain signalling
• Possible lower incidence of chronic post-surgical pain
• Systematic Review and Meta-Analysis shows that propofol improves postoperative analgesia
  • Although the reduction in pain scores occurred via plausible mechanisms the clinical relevance is unclear

Perioperative Neurocognitive Disorders (PND)

• Postoperative cognitive decline (POCD)
  • POCD is a major public health issue
  • Linked significant increase in morbidity and mortality
  • Multifactorial aetiology but anaesthesia technique likely to contribute
• Postoperative delirium (POD)
  • Acute and fluctuating change in attention, awareness, and consciousness
    • Hypoactive
    • Hyperactive
    • Mixed
  • Hypoactive is usually the most common missed
• Emergence Delirium (ED)
  • During the initial emergence from general anaesthesia, some patients experience a period of delirium with agitation or excessive somnolence
  • Complicates postoperative care and family interaction
  • Transient (hours to days)
  • Delay in return to coherent brain connectivity due to higher cortical activity
  • Clear association with anaesthesia technique
  • Less common after propofol anaesthesia particularly in children
• A recent Cochrane Review showed a statistically significant lower incidence of POCD and delirium when TIVA was used
  • The grade of this evidence however was considered low

Potential Anti-cancer Effect

• Vitamin E analogues have been suggested to reduce the risk of cancer
  • Propofol has a similar structure to tocopherol
• Stress response from surgery results in immunosuppression
  • Propofol tends to relatively preserve the immune system
• Propofol effects on
  • Natural Killer Cells (NKCs) enhanced
    • NKCs recognise tumour as non-self
  • Vascular endothelial growth factor (VEGF) inhibited
    • VEGF is the key mediator of angiogenesis in cancer
  • Nuclear factor-kappa B (NF-κB) inactivated
    • NF-κB leads to chemoresistance, tumorgenesis and suppression of apoptosis
  • Hypoxia-Inducible Factor (HIF) decreased
    • HIF linked to angiogenesis, glycolysis and cell proliferation of tumour
  • MicroRNAs & long non-coding RNAs regulated
    • These play an important role in the initiation and progression of cancer
• Key indicators for patients with cancer
  • Recurrence-free survival
  • Overall survival
  • Return to intended oncological treatment (RIOT)
• A large Retrospective Study of over 7000 patients showed mortality was 13.6% for TIVA and 24% for inhalation irrespective of metastatic status or ASA grade of the patient