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
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 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
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 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
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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
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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