TY  - CHAP
M1  - Book, Section
TI  - Chapter 88. Thermoregulation and Perioperative Hypothermia
A1  - Grocott, Hilary P.
A1  - Tran, Tony
A2  - Longnecker, David E.
A2  - Brown, David L.
A2  - Newman, Mark F.
A2  - Zapol, Warren M.
PY  - 2012
T2  - Anesthesiology, 2e
AB  - Adults  thermoregulate  with  their  environment  by  cutaneous  vasomotor  adjustments,  sweating,  shivering,  and  environmental  behavioral  adaptation  (dressing  appropriately,  modifying  environmental  temperature).Neonates  do  not  shiver  but  can  generate  heat  via  nonshivering  thermogenesis.Heat  loss  occurs  via  sweating  and  cutaneous  vasodilation.  Heat  conservation  results  from  cutaneous  vasoconstriction  and  behavioral  adaptation.Although  not  precisely  defined,  core  temperature  reflects  mean  temperature  of  the  well-perfused  organs  (eg,  brain,  heart,  kidney,  and  lungs).Hypothermia  that  develops  during  general  anesthesia  typically  follows  a  predictable  pattern:  (1)  an  initial  rapid  decrease  in  core  temperature  of  between  0.5°C  and  1.5°C  during  the  first  hour  after  induction,  believed  to  be  the  result  of  internal  redistribution  of  heat;  (2)  a  more  gradual  linear  decline  in  core  temperature,  usually  lasting  2  to  3  hours,  that  results  from  cutaneous  heat  loss  exceeding  metabolic  heat  production  (typically  0.5°C/h  to  1°C/h);  and  (3)  a  plateau  phase  when  core  temperature  stabilizes  after  3  to  4  hours  that  results  from  the  thermoregulatory  balance  of  continual  heat  production  and  loss.Following  redistribution-mediated  decreases  in  temperature,  body  heat  loss  occurs  via  radiation  (60%  of  heat  loss)  and  convection  (30%),  with  less  than  10%  occurring  via  evaporation,  and  a  negligible  amount  via  conduction.Postanesthesia  shivering  is  most  likely  mediated  via  a  normal  thermoregulatory  response  to  hypothermia.Hypothermia  during  regional  anesthesia  is  caused  by  the  depression  of  regional  thermal  afferent  input  and  efferent  responses,  such  as  vasoconstriction  and  shivering,  loss  of  heat  to  the  operating  room  environment,  and  redistribution  of  heat  within  the  body.Hypothermia  during  anesthesia  may  be  prevented  or  treated  by  prewarming,  the  control  of  ambient  temperature,  skin  insulation,  warm  intravenous  solutions,  heating  and  humidifying  inspired  gases,  the  application  of  a  forced-air  convective  heating  system,  and  the  use  of  new-generation  circulating-water  convective  heating  systems.There  is  an  abundance  of  experimental  evidence  for  the  neuroprotective  effects  of  hypothermia;  clinical  applications  include  deep  hypothermic  circulatory  arrest  for  cardiac  surgery,  patients  having  suffered  from  witnessed  cardiac  arrest  from  ventricular  fibrillation,  and  possibly  perinatal  asphyxia.  
SN  - 
PB  - The McGraw-Hill Companies
CY  - New York, NY
Y2  - 2024/04/20
UR  - accessanesthesiology.mhmedical.com/content.aspx?aid=56656783
ER  -