Anaesthetic Management of Elderly Patients

Lt Col Md Rabiul AlamMBBS, MCPS, FCPS

Classified AnaesthesiologistDept of Anaesthesiology

Combined Military Hospital, Dhaka, Bangladesh

Scopes

• Anaesthetic definition of elderly & workload• Brief on age-related changes• Importance of good anaesthetic evaluation• Practice of functional reserve/capacity

assessment• Morbidity and Mortality• Decision of Surgery & Planning of Anaesthesia• Perioperative management

Anaesthetic Definition of ‘Elderly’

• WHO: >65 years• UN: 60+ years• AAGBI:

– >80 years = elderly – Physiological

changes/functional decline most marked after 80 years

• Chrono- vs biological age– Chronological age - poor

discriminator of individual surgical risk

– ‘old’ 60 years old vs ‘young’ 80 years old

– Heterogenecity - most consistent feature in the elderly population

Trend in percentage of elderly population in Bangladesh

Ref: http://www.bbs.gov.bd/WebTestApplication/userfiles/Image/PopMonographs/elderlyFinal.pdf

• 2015 = 12.8 Millions• 2020 = 14.0 M• 2025 = 17.2 M

Multimorbidity among Elderlyin Bangladesh

• Conducted among persons aged ≥60 years• Overall prevalence = 53.8%• Multimorbidities:

– arthritis, stroke, obesity, signs of thyroid hypofunction, obstructive pulmonary symptoms, symptoms of heart failure, impaired vision, hearing impairment, and high blood pressure

Ref: Khanam MA, Streatfield PK, Kabir ZN, Qiu C, Cornelius C, Wahlin A. Prevalence and Patterns of Multimorbidity among Elderly People in Rural Bangladesh: A Cross-sectional Study. J Health Popul Nutr 2011;29:406-14.

Size of the problem

• Increasing numbers– > 60’s – quite faster growing section of

the population– 2025- >15% of population will be 60

years and over• Increasing workload

– 50% of elderly will require anaesthesia for surgical intervention in their lifetime

– surgical/anaesthetic advances

Mechanism of Injury to Elderly

Surgery on Geriatric patients in CMH Dhaka

Brief reminder of age-related changes

Age-related cardiovascular changes

• Reduced autonomic responsiveness• SNS activity ↑; Parasympathetic ↓• Baroreceptor reflex activity ↓• β-adrenoceptor responsiveness ↓

• Decreased maximum heart rate• Frank-Starling mechanism- major

mechanism for maintaining stroke volume

Age-related cardiovascular changes

• Increased vascular stiffness– ↑ systolic BP– widening of pulse pressure

• Left ventricular wall thickening– ↓ compliance: impairment of diastolic

function• Greater dependence on atrial function for

ventricular filling– contribute up to 30% of SV

Dependence on High Filling Pressure

Young

End-Diastolic Volume

End

-Dia

stol

ic P

ress

ure

Elderly

Frank-Starling Curve

Aging and Contractility:Response to Exercise/Stress

55

60

65

70

Young

Eje

ctio

n Fr

actio

n(%

)

At Rest Maximal Exercise

Elderly

Response to Anesthesia

• Anaesthetics can:– Remove sympathetic tone

– Dramatic when baseline tone is very high– Directly depress heart, vascular smooth muscle– Diminish baroreceptor reflexes

Add to That …

• Changes in sympathetic tone from waxing and waning surgical stimulus variable depth of anesthesia

• Changes in patient’s volume status

• Results in LABILE BLOOD PRESSURE !

Age-related respiratory changes

• ↓ Vital capacity / ↑ Residual volume• ↓ strength and mobility of muscles• lung elastic recoil ↓• chest wall compliance ↓• spinal collapse (anterior wedging)

• ↑ Closing volume/capacity• ↑ V/Q abnormalities → ↓ gas exchange

Effect of age on closing capacity and FRC

Lung volume (L)

Age (years)

FRC, uprightFRC, supine

Closing

capacity

Postoperative PaO2 in the Elderly

Oxygen by Facemask

No Oxygen supplement

Postoperative PaO2 (mmHg)

Age (years)

Patients with no pre-existing pulmonary disease

Age-related respiratory changes

• ↓ hypoxic and hypercapnic reflex control• Poor upper airway tone

– snoring almost universal• Poor cough (7 fold reduction in sensitivity

of cough reflex)• ↑ risk of aspiration (silent!!)• Chest wall rigidity → more dependent on

the diaphragm

Age-related neurological changes

• ↓ Brain cell mass (10-30% by age 80)– loss of central cholinergic and

dopaminergic cells– 70-80% loss of dopaminergic function

required before symptoms seen in Parkinson’s disease

• Poor reflex control– baroreceptor, thermoregulation

Age-related neurological changes• Blindness

– cataracts, glaucoma– problem with visual analogue scales

• Deafness – problems with comprehension– may be denied by patient

• Cognitive impairment– dementia present in 22% of over 80’s– (life expectancy-50% in 5yrs)

Age-related hepatic changes

• ↓ Liver mass and blood flow– 1% loss/yr after 30 yrs– minor changes in cytochrome P450 activity– variable effect on Phase I reactions; Phase II

not affected• Reduced albumin: altered drug binding

Age-related renal changes

• Marked decline in RBF and GFR (1% loss of function/yr after 30 yrs)

• Plasma creatinine: not good guide of renal function because of reduced muscle mass

• Response to Na concn impaired; less able to excrete Na load

• Reduced ability to dilute/concentrate urine– ↓ thirst perception– fear of incontinence– locomotor problems-inability to get to fluids

Age-related musculoskeletal changes

• Osteoarthritis/Osteoporosis– Immobility → ↑ venous stagnation– Limits ability to exercise

• Poor stability/balance– ↑ risk of accidents esp. in unfamiliar

surroundings• Ligamental laxity

– cervical vertebrae slip

Airway Management:Changes with Aging

Arthritic Changes:• Decreased cervical spine and neck

mobility• Smaller mouth opening• Smaller glottic opening

– Smaller endotracheal tube

Fragile teeth

To be remembered…

• Airway management may be more difficult• Prone to airway collapse (risk of pneumonia)• Higher work of breathing (risk of hypercarbia)• Lower blood oxygen levels

(greater need for supplemental oxygen)• After leaving Recovery room, hypoxia is more

likely in PACU from residual drug/CNS effects

Pharmacology in the Elderly Patients:Increased Bolus Drug Effect

• Decreased protein binding– Higher free, unbound plasma drug levels

• Decreased volume of distribution• Slower redistribution of drug

• ALL of these INCREASE target organ levels!– Examples: Thiopental, Propofol

Bolus Drug Strategy for the Elderly:

• GO LOW !• GO SLOW !• We can always give more!

Temperature Regulation

• Elderly prone to both hypo-, hyperthermia• Lower body metabolism• Decreased ability to change skin blood flow

(less able to hold or get rid of heat)• Hypothermia

– Shivering increases metabolic demand• Increased risk of myocardial ischemia

Postoperative Delirium

• Most common form of perioperative CNS dysfunction

• Acute confusion, decreased alertness, misperception

• Patient may show agitation or withdrawal

• 10-15% of elderly surgical patients

• 30-50% if undergoing cardiac or orthopedic surgery

• Seen after general, regional and MAC anesthetics

• Results prolonged hospital stay and protract postop care

Minimising Postoperative Delirium:Try to Avoid:

• Anticholinergics - atropine and scopolamine (NOT glycopyrrolate)

• Ketamine• Benzodiazepines• Large doses of barbiturates and

Propofol• Pethidine

Common & Treatable Causes of Postoperative Delirium

• Hypoxemia• Hypercarbia• Hypotension• Pain• Sepsis• Metabolic

Morbidity&

Mortality

Highest incidence of mortality and morbidity- NCEPOD data

Traditional diagnostic approach

CNS CVS RS GI UGS Immunesystem

History of presenting illness

Medical/Surgical history

Physical examination

Investigations

Diagnosis and Mx plan

Organ-system based approach for preoperative assessment

CNS CVS RS GI UGS Immunesystem

Medical and surgical history

Activity level and quality

Physical examination

Investigations

Assessment of organ system reserve

Functional Reserve/Capacity Assessment

Integrated functional reserve

• Metabolic equivalence– attempt to quantify metabolic (O2 delivery)

capacity of the patient– estimates the likely outcome of surgery– predicts the likelihood of postoperative

complications• patients unable to reach 4 METS

Examples of metabolic equivalents (METS)Score Activity

1 Eat and dress, walk indoors around the house

2 Walk a block on the level,do light work around the house

4 Climb a flight of stairs or walk uphill, heavy domestic work, run a short distance

6 Moderate recreational activitiese.g., light jogging, golf, doubles tennis

10 Strenuous sports e.g., swimming, running

Risk factors for postop mortality in elderlyASA physical status III and IV

Surgical procedures Major and/or emergency procedures

Co‐existing diseaseCardiac, pulmonary disease, diabetes mellitus, liver, and renal impairment

Functional status <1–4 MET*

Nutritional status Poor, albumin <35%, anaemia

Place of residence Not living with familyAmbulatory status Bedridden

Cardiopulmonary Exercise Testing in elderly patients undergoing major

surgery

Optimisation preoperatively

• Multidisciplinary team approach– Geriatric medical specialist/anaesthetist

• mental state• endocrine• polypharmacy issues

– Cardiologist• murmurs (aortic stenosis)• intractable cardiac failure

– Physiotherapists, nutritionists

Outcome assessment and placement

• Inherent risk of operation– size of stress response– is it appropriate surgery?

• Matching of experience of surgeon/anaesthetist to physical status of the elderly patient

• Plan appropriate anaesthetic technique• Appropriate postop care

– ward/HDU/ICU

Decision of surgery & anaesthetic plan

• Working Party consider– ‘clinical’ & – ‘organisational themes’ that are imp throughout the

peri-op journey• Particular emphasis on interventions that

– the poorer outcomes associated with emergency surgery

• Reciprocal flow of info btw patients & doctors• S/S those require urgent review, & how to access

Decision of surgery/Anaesthesia (cont…)

• Rx plans - discussion btw Patients & Senior doctors• Proposed Mx of expected complications• Assessment & optimisation must start ASAP• Longer for elective surg, shorter for emergency surg• Opportunities to optimise the pathophysiological

condition must not be missed before surgery• Fluid resuscitation / pharmacological manipulation of

chronic co-morbidities before elective surgery

Pre-operative optimisation• Organ-specific morbidity

– diabetes, cardiorespiratory disease and anaemia• Ischaemia

– ↓O2 uptake – analgesia, thermoregulation, antibiotics

– ↑O2 delivery – O2, fluids, medication review, avoidance of hypotension and severe anaemia

• Malnutrition– Oral nutrition and supplementation– Iron, vitamin B12 and folate supplementation provided for subclinical

nutritional anaemia at least 28 days before elective ortho surgery reduces postop morbidity & mortality

– Prolonged pre-op fasting to be avoided (abdominal surgery)

Pre-operative optimisation (cont…)Proactive planning•Anaesthetists should be aware of their role in ‘prehabilitation’•Maintaining/enhancing functional reserve to facilitate postop rehabilitation & discharge back into the community

– Potential risk factors for postop morbidity – Patient info and encouragement – Enhanced recovery protocols, fluid therapy– Avoidance of ischaemia, adequate analgesia, thermoregulation– Selection of the most appropriate anaesthetic technique– Employment of postop care plan– Avoidance of certain medications

Futility

• Inappropriate procedure with no benefit in longevity– heroic surgical therapy– ‘senior’ decision to operate

• Palliative surgery must be provided for symptomatic relief

To sum up………….

Young Elderly