In this article Dr Mevan Gooneratne, an anaesthetic consultant at the Royal London Hospital, runs through a systemic review of the key points regarding multimorbidity in the older surgical patient.
It is no secret that worldwide life expectancy has significantly increased over the last two decades at a rate of approximately five minutes per day. Within the United Kingdom, there are three main factors that influence life expectancy; gender, ethnicity and socio-economic situation. However, quantity does not necessarily confer quality and as a result there have been several epidemiological studies to address the real question as to whether these additional years are with or without health.
Approximately fifty percent of these additional years are associated with some degree of health disability. This is somewhat unsurprising when it is considered that forty per cent of over 70 year olds have three or more comorbid conditions. The presentation of these comorbidities during the perioperative period may be somewhat unique and subtle in the older surgical patient, but nonetheless have a significant influence on their postoperative outcome.
Special considerations in the older surgical patient
There is a significant proportion of undiagnosed and untreated morbidity associated with the older population. The reason for this may be multifactorial, but is commonly due to falsely attributing symptoms of disease to the ‘normal’ ageing process. Impaired cognition can be a barrier to effective symptom reporting as well as a stoic culture in the older population who are ‘unwilling to bother the doctor’.
A patient’s functional capacity has been closely correlated with perioperative outcome. Preoperative evaluation of this key component in the older surgical patient can be extremely challenging. For example, an older person with osteoarthritis may not be able to mobilise due to pain or another individual may report diminished exercise capability, which is in fact due to depression.
As previously mentioned, it is not uncommon for the older surgical patient to present with several different comorbidities. The treatment for one condition can impact on the management of others. For example, optimal management of cardiac disease using ACE inhibition and beta blockade may worsen postural hypotension secondary to autonomic failure from Parkinson’s disease. The cumulative effect of morbidity can also contribute to difficulties when assessing surgical risk. This may make single-organ risk stratification tools (e.g. the Lee cardiac index) less useful, and cumulative scoring systems less sensitive as they fail to incorporate syndromes such as frailty.
Chronic disease management
Presentation for surgery should be taken as an opportunity to ensure disease, disability and frailty are identified, with medical management not only focused on the immediate perioperative period, but also on long term disease management. For example, whilst a patient with newly diagnosed atrial fibrillation may require beta-blockade for rate control during the perioperative period, their thromboembolic risk should also be assessed and treated to ensure long-term risk reduction for a stroke. Similarly, whilst a patient with a blood pressure of 160/95 may be safe to anaesthetise, chronic disease management should be instigated to prevent future morbidity and mortality related to hypertension. It may not be practical to treat and monitor the effect of an intervention for every aspect of chronic disease that is not impacting on the immediate surgery. Long-term issues should be flagged up for further post-operative management to other practitioners such as the GP.
Organ specific considerations for the older surgical patient
The ageing cardiovascular system
Cardiac failure is of more prognostic relevance than coronary artery disease in the perioperative period. Age is a risk factor for both with many patients being asymptomatic from their ischaemic heart disease. Diastolic heart failure is common in older people, and is frequently undiagnosed and may underlie or contribute to postoperative pulmonary oedema.
The prevalence of arrhythmias increases with age; such that about 1 in 5 of people aged over 80 years old have atrial fibrillation. The stress response to the trauma of surgery, in the context of electrolyte disturbances, and often-unnecessary cessation of usual medications can result in tachyarrhythmias, (most commonly atrial fibrillation) in the postoperative period. The prevalence of moderate or severe valve disease is 13 per cent in people aged over 75 years old.
The ageing respiratory system
Chronic Obstructive Pulmonary Disease (COPD) is the most important patient related risk factor for postoperative pulmonary complications, and is commonly undiagnosed in older patients.
Obstructive Sleep Apnoea (OSA) and resultant chronic hypoxaemia can lead to cognitive impairment, personality change and hypertension which are all common age related pathologies in their own right. This can lead to a failure to identify OSA as an underlying and potentially treatable cause.
The ageing kidney
Chronic Kidney Disease secondary to glomerular sclerosis and multimorbidity (hypertension, diabetes and /or ischaemic nephropathy) is often under diagnosed due to over reliance on creatinine measurement as opposed to eGFR or creatinine clearance calculation. Obstructive pathology, such as benign prostatic enlargement, can lead to difficulty with urinary retention and catheter insertion / removal. Iatrogenic injury as a result of medications such as thiazides, non-steroidals and ACE inhibitors are often implicated in renal dysfunction during the perioperative period.
Ageing metabolism and gastrointestinal tract
The prevalence of Type 2 diabetes increases with age, and is rarely seen in isolation as patients often have co-existing pathology and complications such as ischaemic heart disease or autonomic neuropathy. Managing diabetes in the context of multimorbidity can be complex, as seen in patients with cognitive and renal impairment. Tight glycaemic control may not always be appropriate in older patients and should be considered in the context of frequency and potential consequences of hypoglycaemic events. Hypothyroidism is frequently undiagnosed given the paucity of classical symptoms or signs in older age. Although controversy exists regarding mild cognitive impairment in hypothyroidism, screening for it may be important, as it is another risk factor for delirium.
The list of comorbidities that affect the older surgical patient is extensive. Diagnosis is often difficult and their impact on perioperative period variable. Nonetheless, it is unlikely that a single intervention will improve perioperative outcome, but instead a multidisciplinary approach should be adopted: beginning the moment the decision for surgery is considered and continuing through to patient discharge in to the community.
Recommended further reading and references
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