Body composition changes
- loss of lean body mass
- increased body fat
3.decreased total body water
Thermoregulation changes
- decreased hypothalmus function, so impaired
- longer lasting hypothermia
The only CV change that does not occur is
No change in systolic function
Respiratory changes: _____ chest wall compliance
DECREASED chest wall compliance
Respiratory chagnes: Elastic recoil =
Loss of elastic recoil = reduced FUNCTIONAL alveolar surface area available for gas exchange
Respiratory change: comliance
INCREASE in lung compliance (impairs v/q)
Resp. changes: lung tissue elacticity
decreases
Resp changes: net pulmonary compliance
virtually unchanged
Resp changes: alveolar septae
breakdown =
1. increase anatomic and alveolar daed space
2. increase ventilation
=v/q mismatch
Resp changes: shunt and physiologic dead speace
increase
Res changes: vital capcity
decrease
(d/t increasing residual lung volumes and decrease in inspiratory and expiratory reserve volumes)
OVerall resp changes: Min ventilation, lung compliance, lung elasicity, chest wall compliance
Resp changes: FEV1 and FVC
decrease
Resp changes: VC ERV IRV
decrease
Resp changes: FRC RV
increase
Resp changes: TLC
no change
Elderly: CNS nerve tissue sensitivity to local anesthetics? Why?
Increased
-decreased # and diambeter of myelinated nerve fibers
-decrease in nerve conduction velocity
Regional anesthetic sensitivty (intrathecals, epidurals)
Increased sensitivity to intrathecal anesthetics
increased sensitivty to epidural anesthetics
Difficulty of neuraxial/spinals
increased difficulty
Response to EPI test dose
decreased response to EPI test dose = greater risk of false negative responses (d/t reduced myocardial sensitivity to catecholamines)
Drug DOA
prolonged
Pharmacokinetics of prolonged drug DOA
- decreased blood volume
- Steady state volume varies
- renal decline
- hepatic delcine
Elderly and vasopressors
Decreased sensitivity to vasopressors, may need longer to work
Elderly pharm lipophillic drugs Vd
increased Vd
