This article by Dr Sher Mohammad, consultant anaesthetist at Royal Hallamshire Hospital, Sheffield, and others, highlights postoperative delirium and risk factors to increase awareness within clinicians.
The management and perioperative care of elderly patients is often challenging and associated with multiple complications. These problems may happen in immediate postoperative phase which include complications of the airway, cardiac arrhythmias, MI, stroke, electrolyte and glycaemic disturbances. It is also seen especially with the ageing population-postoperative delirium.
Delirium is commonly referred to as being acute confusion state which is often temporary. Delirium can be seen in patients in the postoperative phase. Postoperative delirium especially within elderly patients is associated with increased complications and mortality. It is estimated that between 10%-70% of patients have postoperative delirium (Schenning et al., 2015). Postoperative delirium can be seen in patients who may present with acute confusion which can often fluctuate, conscious level changes and psychotic features including delusions and hallucinations.
Risk factors for DELIRIUM
Postoperative delirium is most seen within elderly patients, notably over the age of 65. Risk factors for postoperative delirium can include elderly patients, diabetes, and ASA classification >2 are risk factors identified for post-operative delirium (Wang et al., 2018). Other risk factors for postoperative delirium include underlying cognitive impairment, dehydration and alcohol abuse (Kang et al., 2020). Risk factors for delirium and perioperative risk factors have been summarised in table 1.
Medications causing DELIRIUM
The most common medications which cause postoperative delirium are atropine, opioids and benzodiazepines. Other medications which cause postoperative delirium have been grouped into mnemonic, which is listed in table 2.
Clinical presentation of Postoperative DELIRIUM
Postoperative delirium is a common delirium complication which is seen mainly after the first few days postoperatively. Postoperative delirium clinical presentation varies within patients. Patients can show cognitive impairment, lethargy, apathy, psychiatric features including hallucinations and delusions. Postoperative delirium can take a few days to resolve and more commonly seen within the elderly population (Griffiths et al., 2014). Differential diagnosis to delirium can include an underlying subdural haematoma, dementia, depression and delirium tremens. The clinical indicators of DELIRIUM are summarised as
D Delirium is a medical emergency (1/3rd preventable)
E Emotional changes e.g. anxiety, anger and aggression
L Lint picking (obvious with central anticholinergic effect)
I Incoherent speech and swearing
R Reversal of sleep pattern
I Indifferent to what is going on
M Memory loss
The diagnosis of postoperative delirium is largely a clinical based diagnosis. Nevertheless, there are diagnostic assessment methods which can also aid diagnosis of postoperative delirium. This includes the Diagnostic and Statistical Manual of Mental Disorders Criteria 5 (DSM 5). The DSM-5 assesses patient cognition, inattention, and consciousness level (Evered et al., 2018). Other assessment methods include the Confusion Assessment Method (CAM). The CAM tool also helps assess inattention, consciousness level, disorganised thinking and cognition. It has been found that CAM and the 3-minute Diagnostic Confusion Assessment Method is extremely useful in the diagnosis of the postoperative delirium (Oberhaus et al., 2021). Furthermore, there is evidence which suggests that the Mini Mental State examination (MMSE) is useful in the assessment of delirium (Segernäs et al.m 2022). There are also markers of delirium which have been demonstrated with the mnemonic of delirium below:
Markers for scoring DELIRIUM are as follows
D Disorientation +1
E Environment recognition problem +1
L Low level of consciousness +1
I Inattentiveness +1
R Rapid onset +1
I Impaired memory +1
U Unusual sleep pattern +1
M Mood changes e.g. agitation +1
The severity of delirium is determined by
Score 0-2, no delirium
Score 3-5, moderate delirium
Score >6-7, severe delirium
Early diagnosis and clinical suspicion are required in the effective management of postoperative delirium. Often other causes of cognitive impairment such as dementia should also be considered as differential diagnosis. However, there is evidence which suggests that there is overlap between dementia and delirium and evidence suggests that these patients have poor prognosis (Hölttä et al., 2011). A collateral history to establish cognitive baseline in diagnosis of dementia, delirium, or both. The management of delirium is through various techniques to ensure patients are safe. Non-pharmacological methods of managing postoperative delirium include careful monitoring by nursing staff to prevent falls, reorientation of the patient with the use of clocks and calendar, visits from family members and access to visual aids such as glasses (Robinson & Eiseman 2008). While pharmacological interventions such as anti-psychotics can also be used in the management of postoperative delirium (Jin et al., 2020). The management of postoperative delirium using a multicomponent approach has been summarised below:
Management of DELIRIUM (multicomponent approach)
D Dehydration managed with balanced salt solution and optimisation of glycaemic status
E Environment should be quiet
L Lab results-management of electrolyte disturbances and renal function
I Imaging of brain
R Re-orientate the patient / Remove and stop the triggering drugs
I Infection treated following NICE guidelines
U Unrecognisable factors sorted (wearing of glasses and hearing aids)
M Mobilise/set up the patient
It is usually advisable to avoid antipsychotic medications to control hallucinations/agitation as they can interrupt the brain natural healing process. This can delay recovery and worsen the condition in some cases. Pharmacological intervention for the treatment of POD in surgical wards is initiated with haloperidol which can be given orally, intramuscularly or intravenously. Initial dose of 1-2 mg of haloperidol is recommended with doses 0.25-0.5 mg every 4 hours for maintenance dosing in elderly. O2 is given via face mask with pulse oximetry and respiratory observation is needed.
Postoperative cognitive dysfunction and anaesthetic management
Postoperative cognitive dysfunction is defined as being a deterioration in cognitive function following surgery. It has been found that postoperative delirium increases the risk of postoperative cognitive dysfunction (Daiello et al., 2019). Currently, there is no evidence which suggest any anaesthetic agent or technique in the management of postoperative cognitive dysfunction.
It is important to closely monitor patients ensuring adequate cardiac output, temperature and management of electrolytes in the intraoperative close monitoring. Recent advances in research have suggested a possible role in cerebral oximetry using near infrared spectroscopy in the management of postoperative cognitive dysfunction (Holmgaard et al 2019). It is also important as part of anaesthetic management to screen patients for risk factors for postoperative cognitive dysfunction including old age, alcohol abuse and pre-existing cerebral disease (Rundshagen 2014).
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- Dr Sher Mohammad, Consultant Anaesthetist Royal Hallamshire Hospital, Sheffield
- Dr Ajmal Khan, Consultant physician and Rheumatologist, Royal Hallamshire Hospital, Sheffield
- Dr Naveena Sukumaran, Associate Specialist Anaesthetics, Royal Hallamshire Hospital, Sheffield
- Dr Amaan Khan, Registrar Cardiology, South Tyneside Hospital, South Shields.
- Dr Asif Zia, Resident Trainee MO, North West General Hospital, Peshawar
- Dr Zain Ahmed Shah, Foundation Trainee, Frimley Health, NHS Foundation Trust.
- Salman Yahya,Trainee anaesthetist,Doncaster Royal Infirmary,NHS Foundation Trust, Thorne Road,Doncaster