Transcript File
Dr. GERTRUDE SIYAKA
Consultant 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 7480yrs
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
Main contributor
system
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 volumehigher 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
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
DISADVANTAGES
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 perioperative 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