18RC1-BETTELLI Perioperative risk assessment in the older person

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1 18RC1-BETTELLI Perioperative risk assessment in the older person Gabriella Bettelli Task Force on Clinical Governance for Geriatric Surgery & Anaesthesia, Italian Health Ministry, Rome, Italy Introduction Reasons why the elderly represent a population at high demand for surgery include: age-related genetic alterations contributing to the development of cancer, degenerative processes affecting the musculoskeletal system, trauma, and falls or benign conditions. 1 Due to genetic factors, lifestyle, associated illnesses and medication, great variability has been observed among this cohort. Progress in medicine has allowed a great number of elderly patients to survive to old age, increasing the number of vulnerable and frail patients presenting for surgery. Risk assessment in the elderly The term elderly refers to a person in which ageing processes, illnesses, malnutrition, difficulties in communication and comprehension, psychological alterations, and specific social needs may coexist, affecting the surgical outcome. The traditional consultation in preparation for anaesthesia 2 captures little information about this, especially about functional status (FS) 3 and frailty, 4 which are important elements in geriatrics. A number of experiences using FS 5 that have proven to predict mortality among older hospitalized patients, and the Comprehensive Geriatric Assessment (CGA) 6 as a tool for preoperative evaluation, have been reported in recent years. A structured approach to surgical risk should consider: the effects of the ageing processes associated illnesses and medication changes in functional status and presence of frailty. Risk factors related to ageing The ageing process Ageing processes induce involution of organs and apparatus, reduce functional reserve and increase sensitivity to drugs. Central nervous system Ageing causes atrophic changes in the brain that cause the common neurological symptoms of memory impairment, decreased cognitive function, deterioration in mobility, decreased sensory input and autonomic nerve system imbalance. These changes are responsible for a reduced requirement for anaesthesia. Psychiatric disorders, depression, dementia, confusion, and catatonia predispose to perioperative cognitive disorders. 1/8

2 Autonomic nervous system Age-induced changes cause a reduction in compensatory reactions, decreased baroreceptor sensitivity and changes in thermoregulation. Orthostatic hypotension and syncope are common and worsened by diabetes. Cardiovascular adjustments to hypovolaemia are compromised. Chronic drug therapy may further impair thermoregulation. Cardiovascular system Physiological changes in vascular elasticity produce decreased arterial compliance and increased systolic arterial blood pressure with left ventricle hypertrophy. This results in decreased betaadrenergic receptor responsiveness and decreased baroreceptor sensitivity. Decrease in sino atrial node automaticity predisposes to arrhythmias. Respiratory system Ageing affects the respiratory system with decreased responsiveness to hypercapnia and hypoxia due to decreased carotid and aortic body sensitivity. Chest wall rigidity increases, with a reduction in compliance. Ventilation-perfusion mismatch and decreased arterial oxygen result. Renal disorders As a consequence of atrophic parenchyma and sclerosis in vessels, profound changes in renal function occur. Decreased renal plasma flow, decreased glomerular filtration rate and decreased ability for urinary concentration or dilution are observed. Ultimately, changes cause increased serum creatinine and urea concentrations, renal failure and electrolyte changes. Endocrine system disorders Endocrine system activity reduces with age, causing impaired glucose homeostasis, decreased thyroxine production, decreased production of renin, aldosterone and testosterone, decreased Vitamin D absorption and increased plasma concentration of antidiuretic hormone. The consequences include diabetes, thyroid dysfunction, decreased sodium retention, increased potassium absorption, and osteoporosis. Haematological and immune system disorders Reduction in marrow production and in T-cell function, together with poor dietary intake and poor vitamin absorption, predispose to anaemia and autoimmune disease. Drug metabolism Due to decreased central nervous system, hepatic, renal and cardiovascular function, all metabolic processes are reduced in the elderly. An increase in fatty tissue and a reduction in lean body mass decrease total body water and increase volume of distribution. These change uptake and clearance of drugs. Decreased drug metabolism and excretion are also related to decreased hepatic and renal function. 2/8

3 Risk factors related to associated illnesses and medication Associated illnesses With ageing, the prevalence of associated illnesses increases, most commonly cardiovascular, respiratory and metabolic conditions. Fifty per cent of patients aged over 70 suffer from one chronic disease, and 30% present more than one. The more frequent associations are between Coronary Artery Disease (CAD) and hypertension, CAD hypertension and diabetes, and cardiovascular and renal disease. Poly-pathology indicates a condition where clinical patterns, disease progression and treatment are more complicated than would be expected from a simple sum of the different illnesses. 7 The ability to cope with physiological change is reduced. The clinical presentation of associated illnesses may vary considerably, hindering diagnosis. Each comorbidity should be evaluated to assess the level of impairment it induces: from no impairment to lifethreatening impairment. The need for treatment may then be assessed: from no need to urgent, and a prognosis given: from excellent to death. A method used widely to rate associated illnesses is the Cumulating Illness Rating Scale (CIRS). Medication The drugs encountered most commonly are cardiovascular (65%): e.g. ACE inhibitors, statins, antiarrhythmic drugs, -blockers and vasodilators, followed by drugs active on the CNS (41%): e.g. benzodiazepines, hypnotics, and analgesics. Many elderly patients take over-the-counter drugs and herbs such as glucosamine, ginseng, and ginko-biloba. A positive correlation between the number of treatments and the iatrogenic risk exists. Frequently patients do not follow their prescriptions carefully. One of the main risks of poly-pharmacy is adverse drug events (ADE). ADEs are more likely and more severe in the elderly, due to physiological changes associated with ageing, coexisting medical problems, multiple drugs being used at the same time and frailty. ADEs represent 10% of causes of hospital admission. Poly-pharmacy may cause weight loss, falls, decline in functional status and cognition, hospitalization and death. Potentially inappropriate prescriptions, or drugs to be avoided or used with caution, include anticholinergics, sedatives, NSAIDs, digoxin, hypoglycaemic agents and warfarin. Despite the risks, these drugs may still be indicated for specific conditions. Anticholinergics Anticholinergics block acetylcholine transmission in central and peripheral nervous system synapses. They inhibit vagal nerve impulses which are responsible for involuntary motor impulses in the gastrointestinal and urinary tracts or in the lungs. Indications for anticholinergics include gastrointestinal, urinary and respiratory disorders, bradycardia, insomnia, dizziness, urinary incontinence. All these conditions are common in the elderly. The elderly have decreased cholinergic reserve and are prone to dementia. This, and other conditions can be worsened by these drugs. Their side effects include cognitive decline, impaired homeostasis, and delirium. They are also at higher risk for developing an anticholinergic toxicity syndrome. Often, additive effects from multiple drugs lead to acute anticholinesterase toxicity. 3/8

4 Sedative, psychotropic, anti-psychotic and neuroleptic drugs Sedative and psychotropic agents are prescribed frequently to treat insomnia and agitation. Risks associated with their use are: falls (risk increased by 60%), memory disturbance, confusion and drowsiness. In principle, drugs with long half-lives, such as flurazepam or diazepam, should be avoided to prevent accumulation. Even though their use is known to cause problems, antipsychotics are used disproportionately in the elderly. Indications for use include dementia, delirium, psychosis, agitation, affective disorders, aggression and agitation. The first generation neuroleptics include haloperidol and flufenazine. Risperidone and olanzapine are second generation drugs. For all these drugs, toxicity is dose dependent. Major side effects include motor disturbances and include dyskinesia, parkinsonism, dystonia, and akathisia. They occur more frequently with older drugs e.g. parkinsonism after haloperidol, but do occur with newer drugs. Autonomic side effects include orthostatic hypotension, tachycardia, Q-T interval prolongation, constipation and urinary retention. Neuroleptic malignant syndrome comprises autonomic hyperactivity, muscular rigidity and delirium and can be fatal. Non-steroidal anti-inflammatory drugs Adverse drug events from NSAIDs in the elderly are estimated to be at least twice that in younger patients, especially with poly-pharmacy. NSAIDs-related ADEs include frequent and severe gastrointestinal side effects, and cardiovascular effects from hypertension due to salt and water retention. Anti-hypertensive drugs, such as furosemide or ACE-inhibitors, may aggravate side effects. COX 2 inhibitors promise more safety, but there are still risks for patients with a previous history of gastric disorders. Beers criteria Beers criteria list the guidance to assess inappropriate drug prescribing in the elderly that is accepted most widely. The list includes 53 medications assigned to one of three categories: drugs that should always be avoided, drugs potentially inappropriate in older adults with particular conditions, and drugs that should be used with caution. Some of the inappropriate drugs in the Beers list are available as over-the-counter products. Adoption of the Beers criteria in preoperative evaluation should reduce ADEs in the perioperative period. Changes in functional status and frailty The sum of behaviours that are needed to maintain daily activities, including social and cognitive functions, is usually indicated as Functional Status (FS). FS is assessed by a dynamic process called Comprehensive Geriatric Assessment (CGA), which describes the patient through a global approach, from their physical health status, cognition and psychological status, the preserved and lost abilities, and the family environment of the patient. The purpose of CGA is to define the corresponding needs and to plan targeted actions. It evaluates: medical condition nutrition cognition and psychological status independence (physical and mental ability to provide to themselves). 4/8

5 The worse the FS is, the worse will be life expectancy, quality of life and clinical outcome. The term frailty indicates a condition in which the capability to cope with stress and physiological change is reduced. There is loss of independence, change to gait, and an increased risk of falls. In the elderly population, about 10% are frail. Both FS and CGA are established well in geriatrics, but they are evaluated only in a small minority of cases preoperatively. Recent reports demonstrate that they help predict surgical outcome. 8,9,10 Very familiar to geriatricians, there is no reason why they should not be included within preoperative assessment for anaesthesia, and performed by trained anaesthetists. Risk related to surgery and anaesthesia Many studies have demonstrated that the frequency of perioperative complications increases with age. Within 6953 surgical inpatients, 23% of which were 70 years or older, 7.9% 80 years or older, and 1% 90 years or older, morbidity and mortality rates increased progressively with age. There was a 0.71% increase in surgical morbidity per year between the ages of 20 and 90 years. The most frequent predictors of morbidity in the year age group included emergency surgery, higher ASA class, duration of surgery, smoking, use of steroids and sensorial diseases. In all age groups, preoperative impairment of FS was a predictor of adverse outcome. After 80 years, predictors included blood transfusion, emergency surgery, weight loss and COPD. The role of patient related factors as predictors of adverse outcome has been confirmed in other reports. 7 In an Australian study on 1102 consecutive patients over 70 years, 8 the 30-day mortality rate was 6%; 19% had postoperative complications and 20% spent at least 1 night in ICU. Preoperative factors associated with 30-day mortality included age over 70 years, higher ASA class and albumin level < 30 g.l -1. Postoperative factors associated with 30- day mortality were: unplanned ICU admission, sepsis and acute renal impairment. With the exception of thoracic surgery, the type of surgery was a weaker predictor of mortality than patient-related factors such as age, higher ASA class, low plasma albumin and reduced FS. Strategies to optimise the condition of patients before surgery and prevent, or at least treat adequately any complications may improve patient outcomes. 9 Safety in the OR and the elderly In 2007, the World Health Organisation (WHO) defined 10 objectives essential for safe surgery to be adopted internationally. Some of the objectives require to be adapted for the elderly. Objective 1: The team will operate on the correct patient at the correct site A specific risk exists in the presence of cognitive impairment for the patient to confirm their identity. This emphasises the need for identification bracelets in addition to the WHO safety checklist. Objective 2: The team will use methods known to prevent harm from anaesthetic administration, while protecting the patient from pain Specific risk is linked to age-related patho-physiological changes, comorbidity, poly-pharmacy, altered pharmacodynamics and kinetics, chronic dehydration and reduced muscular mass. The consequences are exaggerated drug effects, haemodynamic instability, difficulties with fluid management, and hypothermia. Postoperative pain treatment in demented patients requires appropriate pain scales, such as the Pain In Advanced Dementia scale (PAINAD). 10 5/8

6 Objective 3: Problems related to patient positioning on the surgical table When positioning older patients on the surgical table, risks exist related to osteoarthritis, skin tissue trophism, and lying in the lateral position. A consequence can be pressure ulcers, which will prolong hospital stay. Alopecia due to prolonged immobilization of the head has been documented after cardiovascular and gynaecological procedures. Objective 4: The team will avoid inducing an allergic or adverse drug reaction known to be a significant risk to the patient Poly-pharmacy in the elderly increases sensitivity to drugs and drug induced ADEs, reduces compliance with medication, and patients may be unable to give reliable clinical and drug histories. Objective 5: The team will use methods known to minimize risk of surgical site infection Specific adjunctive risk is linked to age-related reduction in functional status, independence, nutritional status and immune deficiency, which make the older patient more vulnerable toward infection. Conclusions In recent years it has been recognised that older surgical patients have different requirements and need specific attention and care. In the field of internal medicine, a dedicated discipline developed at the beginning of the last century under the name of geriatrics. 11 Nothing equivalent has developed in the field of surgery where, in the great majority of cases, older patients continue to be treated as simple adults. Associated illnesses are usually considered per se, with no consideration for the pattern that they may assume in the elderly. It is unusual for surgeons and anaesthetists to use concepts such as FS, frailty or consider poly-polypharmacy. Beers criteria are usually not used by surgeons or anaesthetists. With experience from ortho-geriatrics, 12,13 orthopaedics is a unique example of a collaborative approach in caring for the elderly surgery patient. However, this innovation has developed bilaterally between two specialities, 14 rather than being adopted for all patients. Promoting educational programmes for surgeons and anaesthetists and developing a specialist approach for geriatric surgery and anaesthesia offer a means for substantial improvement in this field. 6/8

7 Key learning points Risk in the elderly surgical patients is related to: ageing processes associated illnesses and medication changes in functional status and frailty A validated method to assess consequences of ageing processes, and the impact of associated illnesses and functional status (FS) is the Comprehensive Geriatric Assessment (CGA), which can also be performed by anaesthetists The Beers list represents an useful tool for reviewing concurrent medication preoperatively The Mean 30-day mortality rate is reported to be 6% and postoperative complications rates are about 20%. Both display a linear increase with age Preoperative factors associated with 30-day mortality include age over 70 years, high ASA class and albumin level < 30 g.l -1. Postoperative factors are unplanned ICU admission, sepsis and acute renal impairment With the exception of thoracic surgery, the type of surgery is a weaker predictor of mortality than patient-related factors Safety in the operating theatre presents specific challenges System strategies aiming to optimize preoperative status and prevent complications may improve outcome Promoting educational programmes and increasing specific culture represent a key factor for improvements in geriatric anaesthesia. 7/8

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