TY  - CHAP
M1  - Book, Section
TI  - Geriatric Anesthesia
A1  - Butterworth IV, John F.
A1  - Mackey, David C.
A1  - Wasnick, John D.
Y1  - 2018
N1  - 
T2  - Morgan & Mikhail's Clinical Anesthesiology, 6e
AB  - KEY  CONCEPTS  In  the  absence  of  coexisting  disease,  resting  systolic  cardiac  function  seems  to  be  preserved,  even  in  octogenarians.  Increased  vagal  tone  and  decreased  sensitivity  of  adrenergic  receptors  lead  to  a  decline  in  heart  rate.  Elderly  patients  undergoing  echocardiographic  evaluation  for  surgery  have  an  increased  incidence  of  diastolic  dysfunction  compared  with  younger  patients.  Diminished  cardiac  reserve  in  many  elderly  patients  may  be  manifested  as  exaggerated  decreases  in  blood  pressure  during  induction  of  general  anesthesia.  A  prolonged  circulation  time  delays  the  onset  of  intravenous  drugs,  but  speeds  induction  with  inhalational  agents.  Aging  decreases  the  elasticity  of  lung  tissue,  allowing  overdistention  of  alveoli  and  collapse  of  small  airways.  Residual  volume  and  the  functional  residual  capacity  increase  with  aging.  Airway  collapse  increases  residual  volume  and  closing  capacity.  Even  in  normal  persons,  closing  capacity  exceeds  functional  residual  capacity  at  age  45  years  in  the  supine  position  and  age  65  years  in  the  sitting  position.  The  neuroendocrine  response  to  stress  seems  to  be  largely  preserved  or,  at  most,  only  slightly  decreased  in  healthy  elderly  patients.  Aging  is  associated  with  a  decreasing  response  to  β-adrenergic  agents.  Impairment  of  Na+  handling,  concentrating  ability,  and  diluting  capacity  predispose  elderly  patients  to  both  dehydration  and  fluid  overload.  Liver  mass  and  hepatic  blood  flow  decline  with  aging.  Hepatic  function  declines  in  proportion  to  the  decrease  in  liver  mass.  Aging  produces  both  pharmacokinetic  and  pharmacodynamic  changes.  Disease-related  changes  and  wide  variations  among  individuals  in  similar  populations  prevent  convenient  generalizations.  The  principal  pharmacodynamic  change  associated  with  aging  is  a  reduced  anesthetic  requirement,  represented  by  a  reduced  minimum  alveolar  concentration  (MAC).  Elderly  patients  display  a  lower  dose  requirement  for  propofol,  etomidate,  opioids,  benzodiazepines,  and  barbiturates.  
SN  - 
PB  - McGraw-Hill Education
CY  - New York, NY
Y2  - 2024/04/19
UR  - accessanesthesiology.mhmedical.com/content.aspx?aid=1161431610
ER  -