The use of anaesthetics in the elderly surgical population

Miller, D. et al. | Intravenous versus inhalational maintenance of anaesthesia for postoperative cognitive outcomes in elderly people undergoing non-cardiac surgery | Cochrane Database of Systematic Reviews, Issue 8, 2018 

Background
Anaesthesia during surgery in elderly people (more than 60 years of age) is increasing.  Traditionally, general anaesthesia is maintained with an inhaled drug (a vapour which the patient breathes in) which needs to be adjusted to ensure that the patient remains  unconscious during surgery without receiving too much anaesthetic. An alternative method is to use propofol which is injected into a vein throughout the anaesthetic procedure; this is called total intravenous anaesthesia (TIVA).  Elderly people are more likely to experience confusion or problems with thinking following surgery, which can occur up to several days postoperatively. These cognitive problems can last for weeks or months, and can affect the patients’ ability to plan, focus, remember, or undertake activities of daily living.

This review looked at two types of postoperative confusion: delirium (a problem with awareness and attention which is often temporary) and cognitive dysfunction (a persistent problem with brain function).

TIVA with propofol may be a good alternative to inhaled drugs, and it is known that patients who have TIVA experience less nausea and vomiting, and wake up more quickly after anaesthesia. However, it is unknown which is the better anaesthetic technique in terms of postoperative cognitive outcomes.

Review question
To compare maintenance of general anaesthesia for elderly people undergoing non-cardiac surgery using TIVA or inhalational anaesthesia on postoperative cognitive function, number of deaths, risk of low blood pressure during the operation, length of stay in the postanaesthesia care unit (PACU), and hospital stay.

Study characteristics
The evidence is current to November 2017. We included 28 randomized studies with 4507 participants in the review. We are awaiting sufficient information for the classification of four studies.  All studies included elderly people undergoing non-cardiac surgery and compared use of propofol-based TIVA versus inhalationalagents during maintenance of general anaesthesia.

Key results
We found little or no difference in postoperative delirium according to the type of anaesthetic maintenance agents from five studies (321 participants). We found that fewer people experienced postoperative cognitive dysfunction when TIVA with propofol was used in seven studies (869 participants). We excluded one study from analysis of this outcome because study authors had used methods to anaesthetize people which were not standard. We found little or no difference in the number of deaths from three studies (271 participants). We did not combine data for low blood pressure during the operation or length of stay in the PACU because we noted differences in studies, which may be explained by differences in patient management (for low blood pressure), and differences in how length of stay in the PACU is defined in each study . We found little or no difference in length of hospital stay from four studies (175 participants).

Full review available at the Cochrane Library

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Quality of clinical practice guidelines in delirium

Bush, S.H. et al. (2017) BMJ Open. 7:e013809

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Objective: To determine the accessibility and currency of delirium guidelines, guideline summary papers and evaluation studies, and critically appraise guideline quality.

 

Conclusions: Delirium guidelines are best sourced by a systematic grey literature search. Delirium guideline quality varied across all six AGREE II domains, demonstrating the importance of using a formal appraisal tool prior to guideline adaptation and implementation into clinical settings. Adding more knowledge translation resources to guidelines may improve their practical application and effective monitoring. More delirium guideline evaluation studies are needed to determine their effect on clinical practice.

Read the full review here

European Society of Anaesthesiology evidence-based and consensus-based guideline on postoperative delirium

Aldecoa, C. et al. (2017) European Journal of Anaesthesiology. 34(4) pp. 192-214

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Postoperative delirium (POD) is an adverse postoperative complication that can occur in patients of any age, from children to the elderly. Its incidence varies in the various age groups and is substantially influenced by patient-related risk factors that are variably distributed and differentially accumulate in the different age groups. Elderly patients are generally thought to be at higher risk because predisposing risk factors such as cognitive impairment, comorbidity, sensorial deficits, malnutrition, polymedication, impaired functional status and frailty (a condition that can only be observed among aged patients) accumulate and overlap with ageing.

Moreover, POD (refer to the specific definition in the ‘Paediatric patients’ section) is a common complication in children of pre-school age (5 to 7 years): whether this is due to age-related psychological issues or to additional inflammatory effects on the brain cannot currently be determined. There is a limited number of studies on cognitive outcomes in children. For the USA, the Food and Drug Administration (FDA) recently recommended cautious indications for anaesthesia and surgery in children aged less than 3 years. In Europe, the ESA launched an initiative, the EUROpean Safe Tots Anaesthesia Research (Eurostar) Initiative Task Force to promote translational research on anaesthesia neurotoxicity and long-term outcomes after paediatric anaesthesia and surgery.

Read the abstract here

Protocol Lacking for Post-op Delirium

While 70% of anesthesiologists say they “frequently” or “occasionally” encounter postoperative delirium in their practices, more than three-fourths (77%) lack a process to screen for at-risk patients | Anesthesiology News

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A survey of nearly 300 anesthesiologists revealed that postoperative delirium is extraordinarily common worldwide, with 95% of respondents reporting they have had such a patient. However, 60% said they did not commonly discuss possible neurologic complications with their patients prior to surgery. In addition, 84% said their hospital or clinic did not have protocols to prevent postoperative delirium and 73% said their facility lacked protocols to manage delirium when it occurred. Of anesthesiologists without a screening process, 88% said they would consider implementing one.

Read the full article here