Dr. GERTRUDE SIYAKAConsultant Anaesthesiologist

Steve Biko Academic Hospital

Introduction Normal physiological changes

associated with ageing Pharmacokinetics and

pharmacodynamics in the elderly Pre-operative assessment Day case surgery Anaesthesia for orthopaedic surgery Post operative complications References

Life expectancy in US and Europe now 74-80yrs

Medical progress most effective in change

Demographical data indicate the elderly most rapidly growing of population

Use of health care services by elderly disproportionately higher than younger patients

Elderly patients now routinely undergo operative procedures

Ageing a complex multifactorial process Universal and progressive physiological

process marked by declining end organ function, imbalance haemostatic mechanisms, increasing pathologic processes

Theories on numerous and diverse: evolutionary, molecular, cellular and systemic

Include mutation accumulation, programmed cell death, cumulative environmental damage, free radical damage

End result is impaired function and progressive decline

Age –related changes occur in all organs

1. Cardiovascular system Main contributor for adverse outcome

in peri-operative period Heart LV hypertrophy frequently evolves and

related to elevated SVR Cardiac mass increases- concentric

hypertrophy Interstitial fibrosis in myocardium leads

to poor contractility

Stiffness myocardium affects diastolic relaxation as well as systolic contraction

Prolonged systolic myocardial contraction then ensues

LV relaxation time delayed at time mitral valve opening

Early diastolic filling declines Age related increase in LA volume and

contribution to diastolic filling shows importance of “atrial kick”.

Ventricular eccentric hypertrophy and loss wall tension may lead to valve closure deficiency and regurgitant valves

Aortic valve sclerosis common CO decreases linearly after 3rd

decade at 1% per year even in healthy individuals

80 yr old will have approx 50% CO compared to when was age 20

CI decreases at 80% per year

Vasculature Arteriosclerosis is the hallmark feature Contributing factors are:

hypertension ,hypercholesterolemia, oxidative stress and genetic disposition

Arteriosclerosis an irreversible process CEA and AAA repair most frequently

performed procedures in elderly

Adrenergic sensitivity Plasma CATS levels after stimuli not

been shown to diminish Blunted B-receptor responsiveness

possibly due to down regulation and decreased agonist binding to receptor

Increase in vigil tone There is 20% loss of HR response

during exercise in 75 yr old compared to 25 yr old

2. Respiratory system Typical barrel chest appearance results in

increased work of breathing and reduced compliance

Loss of elastic recoil within the lung and changes in surfactant production leads to limited maximal expiratory flow

Lung volumes: increase in RV, closing capacity, FRC , TLC (minimal). Decrease in VC

Flow :progressive decrease in FEV1 /FVC Oxygenation: decrease efficiency in alveolar

gas exchange resulting in PaO2and increase alveolar –arterial gradient

Impaired response to hypoxia, hypercarbia and mechanical stress

3.Renal Renal mass decreases by 30% by age

80 Renal blood flow and creatinine

clearance decrease Poor electrolyte handling and capacity

to concentrate or dilute urine Excretion of some anaesthetic agents

is impaired

4. Nervous system Brain weight declines by 10% Cerebral atrophy common Cerebral blood supply reduced and

vertebrobasilar insufficiency common Gradual decline in cognitive function,

memory and reasoning performance Confusion common Altered sleep pattern Thermoregulation: poor response to

hypothermia

Pharm’kinetics influenced by in plasma protein binding, lean body mass, changes in circulating blood volume and metabolism and excretion of drugs

Lean body mass reduced Protein binding sites reduced Decrease in circulating blood volume-

higher than expected initial plasma concentration of drugs

Polypharmacy Elderly more sensitive to anaesthetic

agents

Get medical history, current functional status and medication

ASA status Lab investigation as appropriate for

anticipated surgery and medical issues: CXR,12 lead ECG, FBC , U/E and CT scan as appropriate

Worry about polypharmacy Enquire about social circumstances Continue B blockers, but discontinue

ACEIs, Digoxin Premedicate if appropriate

NO MAGIC BULLETS Effects of initial dose on single

patient highly variable Smaller doses compared to younger

patients Low threshold for invasive monitoring Position carefully to avoid pressure

and nerve injuries Avoid hypothermia

An excellent option for carefully selected pts

Pre-operative evaluation to determine functional reserve , physical status ,and rational pre-operative testing but must be done early enough to allow for interventions

Suitable for minimally invasive surgery (eyes, urology) in maximally co-morbid pts

Any anaesthetic technique :LA ,RA ,GA Premed as appropriate.

ADVANTAGES DISADVANTAGES

RA provides good post –op analgesia

Peri-op MI less frequent Oculocardiac reflex less

frequent PONV unlikely Short stay in PACU Pts eat ,drink earlier Discharge home earlier

Control IOP limited Long surgery

contraindicated Need pt co-operation Pt coughing ,movement

not avoided Ventilation not

controlled( hypercarbia, hypoxia)

GA may be needed Same drugs used but consideration

to dosing the elderly LMA can safely be used but proviso Manage pain adequately Consider prophylaxis for PONV

Number of elderly pts in orthopaedic surgery steadily growing (hip fractures, OA, rheumatoid arthritis)

Elderly pts may have significant organ dysfunction; cardiorespiratory, renal and neurological.

They may be malnourished No single clear anaesthetic technique.

RA preferred Use of cement during surgery known to

be associated with intra-operative morbidities

Tourniquet use common Sedation often needed when RA used DVT prophylaxis necessary for major

joint surgery Antibiotics routinely used but must be

given before tourniquet Blood loss may significant in revision

surgery Neuraxial blockade with opioid provides

good analgesia

Prolonged use of urinary catheters should be avoided

Goal is early and efficient rehab Central neuraxial blockade reduces

surgical stress by blocking nociceptive inputs

Geriatric pts have decreased functional organ system reserve and are thus tolerate surgical stress poorly

RA recommended the elderly and has advantage over GA

Older pt at risk for complications in peri-operative period due to co-morbid diseases and the ageing process

Cardiovascular complications include MI, dysrhythmias esp. AF, and cardiac arrest

Pulmonary complications: atelactasis , pneumonia

Neurological complications: stroke, POD,POCD. Post operative delirium(POD): acute

confusional state Post operative cognitive dysfunction(POCD):

long term impairment in memory, concentration ,language and social integration

Surgery is now performed in older ,sicker elderly patients

Ageing is associated with numerous physiological changes

Surgery not always benign because of high prevalence of co-morbidities

Adjust anaesthetic technique Aim to minimise peri-operative

complications

Available on request