Geriatric Anesthesia

1. Anesthesia Technology جامعة العين كلية التقنيات الطبية Anaesthesia for geriatric surgery Lecture10 Majid Fakhir Mutar MScanesthesia technologist الفصل الاول المحاضرة العاشرة (10) نظري مادة التخدير/ المرحلة الثالثة/ جامعة العين2022-2021 Majid.Mutar@alayen.edu.iq

2. Introduction The incidence of perioperativecomplicationsis much higher in these patients due toreduced functional reserve and a high incidence of co-morbidity, but thesecomplications can be minimizedby: • careful preoperative assessment, • a meticulousanaesthetic technique and • good postoperative care. • Age related physiological changesAgeing is a process where progressive cell loss occurs.The concept of “functional reserve” is derived from the difference between the basallevel of organ function at rest and the maximum level of organ function that can beachieved in response to increased demand, for example during exercise or in responseto surgical stress. Functional reserve is often reduced in elderly patients, and isthought to be a major factor in the increased morbidity and mortality of the elderlypopulation.

3. Alterations in Organ Function Reduction in cardiovascular, pulmonary, renal and central nervous systemfunction may be the most important determinants of outcome from surgical procedures under general or regional anaesthesia. • Cardiovascular system • Ischaemic heart disease is common in affluent societies. The net effect on the heart isreduced cardiac output. • In contrast, valvular heart disease secondary to rheumaticfever is more commonly seen in developing countries. • Over 50% of patients will have mitral valve disease.Aortic lesions are less common. • The reduced cardiac output in heart disease compromises blood flow to the kidneysand brain, and therefore both the kidneys and brain are prone to perioperativeischaemia. • The physiological response to cardiovascular stressors (such as hypovolaemia) maybe blunted due to reduced baroreceptor sensitivity and autonomic function. • This lackof compensation may be significant if the patient is taking medication such as betablockers or ACEinhibitors. • Atrial fibrillation (AF) in the elderly population is common. The fast ventricular ratein AF leads to reduced cardiac output. Preoperatively, a patient in AF should ideallybe cardioverted, or controlled to <100/minute.

4. Alterations in Organ Function • Respiratory systemPulmonaryelasticity, lung and chest wall compliance, total lung capacity (TLC) will decrease. Although functional residual capacity (FRC) is unchanged, closing capacity(CC) rises progressively with age, and may become greater than the FRC - this occurs in the supine position at 44 years of age and in the upright position at 66 years. • The end result of these changes is airways collapse, VQ mismatch and hypoxaemia. • The efficiency of gas exchange is reduced, and as a result PaO2 decreases with age although PaCO2 remains constant. • Atelectasis, pulmonaryembolism and chestinfections are all more common in elderly patients, particularly following abdominal or thoracic surgery. • Early mobilisationand good analgesia following abdominal surgery help reduce lung atelectasis and collapse.

5. Alterations in Organ Function • Renal system • Glomerular filtration is reduced. Clearance of renally excreted drugs is reduced, and fluid balance is more critical as responses to both fluid loading and dehydration are impaired. • Renal function may deteriorate rapidly in hypovolaemic patients. Closemonitoring of hourly urine output after major surgery should be routine. • Nervous system • An age-related decline in central nervous system (CNS) function is common. As aresult, confusion is more common, both pre and post-operatively. • EndocrineThe incidence of diabetes is increased in the elderly. Diabetics frequently havecardiovascular, renal, neurological and visual impairment, and require control ofblood glucose levels during the perioperative period.

6. Alterations in Organ Function • Pharmacology • Pharmacokineticsmay be altered, with reduced hepatic and renal blood flow and a reduction in total body water. Plasma proteins are often reduced, resulting in reduced protein binding of drugs and metabolites, thereby increasing free drug levels and possible toxic effects. • Pharmacodynamicsmay also be altered, with increased sensitivity to many agents, especially CNS depressants. • Minimum alveolar concentration (MAC) decreases steadily with age. • Long-term medication should usually be continued throughout the hospital stay. • MusculoskeletalArthritis usually affect the elderly. This may limit exercise tolerance and makes itdifficult to assess fitness. Osteoporosis and ligament laxity makes epidurals andspinals technically difficult; in addition, the patient is prone to fractures or dislocationof joints (including the cervical spine) while anaesthetised. Care should be taken withpatient movement and intra-operative positioning. Vulnerable pressure points shouldbe well padded.

7. PREOPERATIVE PREPARATION • Assessment • A full historyand thorough clinical assessment is required. • An ECG is required for all patients. • A chest X-ray should be arranged for patients with known malignancy orpossible tuberculosis, and for anyone with symptomatic cardiovascular orrespiratory disease. • Note the level of cognitive function. • Assessment of exercisetolerance and functional ability is important. • Thebaseline functioning of the patient should be well documented. If a decreasedfunctional reserve is detected, a high- care or intensive care facility may beappropriate post-operatively. • The American Society of Anaesthesiologists (ASA) score should be recorded -it remains a good predictor of outcome in the elderly

8. Resuscitation/optimisationpre-operatively • Dehydration is common. • Preoptimisationenhance the oxygen delivery to the tissues during the perioperative period, by using fluid therapy, oxygen and possibly inotropic agents. • PERIOPERATIVE CAREIn general the full range of anaesthetic drugs and techniques used for young, fit adultsmay be used in elderly patients, within the limitations of their physiology.Modification of the techniques, and particularly drug doses, may be required. • Induction of anaesthesiaArm-brain circulation time is increased, and induction agent dose requirements are reduced. • Titrate drugs slowly against effect, and inject into a running intravenous infusion. • Thiopentone or propofol are both useful but should be given slowly to avoid overdose. • An induction dose of propofol may result in hypotension and require a vasopressor. • Avoid ketamine in the presence of cardiac disease as the tachycardia and hypertension that may result can increase myocardial oxygen consumption and precipitate ischaemia. However, ketamine’s hallucinogenic effects are not as marked in the elderly, and that it remains a very safe and effective analgesic, anaesthetic and sedative.

9. Maintenance of anaesthesia • Maintenance of anaesthesia with inhalational agents is a suitable technique forelderly patients. • Halothane has the advantage of being non-irritant to the upper airway andrespiratory tract, although it sensitises the myocardium to catecholamines andso may predispose to tachyarrhythmias. • Fluid managementCareful peri-operative fluid balance is mandatory in the elderly. Always considermeasuring the CVP with large fluid shifts. Excess fluids in an elderly patient, cancause pulmonary oedema. Conversely, dehydration in the elderly can precipitate renalfailure.

10. POSTOPERATIVE CARE Oxygen therapy • It is good practice to prescribe post-operative oxygen therapy for all elderly patients, and especially following abdominal or thoracic surgery. • Nasal cannulae are often better tolerated than facemasks. High dependency careHigh dependency care or intensive care facilities may improve the long-term outcome of elderly patients, especially those undergoing urgent or emergency surgery.AnalgesiaConsider prescribing a regular simple analgesic such as paracetamol, and useNSAID’s with caution; the complications of NSAIDs, including renal impairment andpeptic ulceration, are more prevalent in older patients.Regional techniques or an IV opioid infusion (with appropriate close supervision)may be the most appropriate method of pain relief.

11. THANK YOU