Transcript Geriatric Anaesthesia

Dr J Lemmer
 7%
of population in
1996 - 8% in 2011
 Often difficult to
get good history
 Comorbidities,
polypharmacy, less
functional reserve
 Handle with care!
 20%
of octogenarians has dementia
 Neuronal loss, incr astrocytes and microglia
 Decr cerebral blood flow but autoregulation
is preserved
 Autonomic dysfunction: BP, Temp,
gastroparesis
 Less volume of CSF, decr blood flow – spinal
lasts longer and spreads higher
 Decreased
MAC – 4% per decade after 40
 IV induction doses, LA doses
 POCD after GA and regional blocks: use shortacting drugs and avoid Atropine
Fibrosis of:
 Media of arteries
 Myocardium
 Conduction system
 Baroreceptors
Calcification of valves
Normal EF on U/S!
Decreased
compliance due
to:
 Fibrosis
 HPT
 IHD
 AS
Atrial kick, HR = NB
BUT often AF
Physiologic B-blockade
 high vagal tone
 decreased B-receptor
sensitivity
Reflex tachycardia insufficient
during hypovolemia,
hypotension, hypoxia
Careful of PEP!
 Good
pre-op history and examination
 SLOW IV induction – prolonged circulation
time
 Impatience WILL lead to OD
 Maintain sinus rythm and slow HR
 Expect decreased response to inotropes
 Barrel
chest due to vertebral
collapse
 Often edentulous – difficult
mask ventilation
 TM/ C-spine arthritis – difficult
intubation
 Unstable upper airway –
snoring, sleep apnoea
 Flat diaphragm, weak
intercostal m.
 Large anatomical dead space
Obstructive changes
Less elastic recoil
Lower alveolar P to keep small
airways open – collapse
(closing capacity increases)
 Air trapped in alveoli (RV
increases)
CC > FRC
 Airway collapse during tidal
breathing
 Lower PaO2
Restrictive
changes
Stiff lungs and
chest wall –
decreased VC
Increased work of
breathing
 Blunted
response
to hypercapnea
and hypoxia
 Decreased
laryngeal reflexes
– aspiration
 Decreased cough
reflex - pneumonia
 Beware
of premedication
 Small tidal volumes, high frequency
 Opioids, BDP has exaggerated side-effects
 Good post-op pain control
 Decr
RBF, nephron loss
 Decr GFR and Creatinine
clearance but s-creatinine
unchanged
 Urea increases with 0.2 mg/dL
per year
 Impaired Na and K handling
 Impaired concentration and
dilution ability – dehydration or
fluid overload
 Often on diuretics
 Impaired drug excretion
 Decreased
hepatic blood flow and function
 Decreased Alb synthesis – binds Opioids, NTP, BDP
 More fat, less m.
 Intracellular dehydration – decr TBW
 Water-soluble drugs: smaller Vd Morphine,
M.relaxants
 Lipid-soluble
drugs: larger Vd
 Onset
rapid if CO is low
 Slow onset if V/Q
mismatch
 Exaggerated cardiac
depression and limited
reflex tachy = severe
hypotension
 Slow emergence (large
Vd, decr hepatic
metabolism, decr
pulmonary function)
 NTP
dose must be halved (slower
redistribution away from brain)
 Propofol – reduce dose. Some good news:
elimination is not delayed in elderly
 Etomidate = safest
reduce initial dose
delayed elimination
 Very sensitive to Midazolam
 Stay away from Diazepam!
Morphine
Vd is halved in elderly – halve
your dose
M3G and M6G accumulate –
allow more time between
doses/ titrate with PCA
Remifentanyl TCI = safest
 Onset
is 2x slower due to
low CO – be patient before
you intubate!
 Recovery prolonged but not
for atracurium and cis-.
 Interindiv. variation –
Use N. Stimulator!
Pre-operative
 Why did she fall?
 History –
>4METS?
 Physical exam
 Special
investigations
ECG? NOT if
asymptomatic, no
risk factors and low
risk surgery
 proBNP
 Don’t
delay >48hr!
 DVT prophylaxis !!
 Consider risk vs
benefit
GA vs Regional
 Studies show mixed results
 2009 Meta-analysis showed
less VTE and less bleeding
with regional techniques
for hip/knee replacements
(OR 0.45)
 THR –lateral position
uncomfortable
 Poor resp vs poor cardiac
function
Spinal
 Pain makes
positioning
difficult
 Exclude AS!
 Be ready for
hypotension:
fluids, PEP
 Sedation
GA
 Invasive Monitoring
 Iv induction agent?
 Inhalational agent?
 M. Relaxant?
 Pain control
 Don’t forget the
basics –blood loss,
temp, AB etc
POST-OP
 Pain control
 Early mobilization
 Monitor for complications
Trop T level after 6-12 hrs?
 Delirium: exclude treatable cause – pain, u.
retention, hypoxia, hypotension, fluid+
electrolyte abN, fat embolism