title: Monitoring of regional cerebral oxygenation by near-infrared spectroscopy during continuous retrograde cerebral perfusion for aortic arch surgery.
abstract: OBJECTIVE
  To assess the value of monitoring of regional cerebral oxygen saturation (rSO2) during aortic arch surgery using continuous retrograde cerebral perfusion (CRCP) in conjunction with profound hypothermic circulatory arrest (HCA).
  
  
  METHODS
  The rSO2 of 12 consecutive patients was monitored non-invasively using near-infrared spectroscopy (NIRS) and the data were analyzed statistically.
  
  
  RESULTS
  The mean duration of HCA with CRCP was 62-/+14.1 min. The mean CRCP flow rate was 226+/-163 ml/min. Surgical outcomes were favorable with only a single hospital death (8.3%). However, the rSO2 decreased gradually in all patients during HCA, even combined with CRCP, and fell to 46+/-8.7% on average. It did not change so greatly before HCA and returned finally to its initial level at the end of re-warming. Only one patient developed a permanent neurologic deficit; this patient showed the greatest decrease of rSO2 from 56% to 29% after the longest HCA of 88 min. Two parameters, End-rSO2 (the ratio of post- to pre-HCA rSO2) and delta-rSO2 (the rate of decrease from preto post-HCA rSO2) were obtained since the initial values of rSO2 before surgery differed. There were linear correlations between the CRCP flow rate and each of these two parameters. A multiple regression analysis also revealed a linear equation relating the parameters, which allowed prediction of the safe duration of HCA in different conditions of CRCP and a more favorable adjustment of the CRCP condition in each patient.
  
  
  CONCLUSIONS
  The study suggests that the combination of HCA and CRCP has a limit of safe duration in spite of its potential usefulness for brain protection, and that rSO2 monitored by NIRS is useful in testing for adequate brain protection. It is hoped that monitoring of rSO2 can facilitate prediction of the safe duration of HCA with CRCP and a more favorable adjustment of CRCP.
authors.affiliation: Department of Cardiovascular Surgery, Tenri Hospital, Nara, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ogino
authors.forename: Y
authors.initials: Y
authors.lastname: Ueda
authors.forename: T
authors.initials: T
authors.lastname: Sugita
authors.forename: K
authors.initials: K
authors.lastname: Morioka
authors.forename: Y
authors.initials: Y
authors.lastname: Sakakibara
authors.forename: K
authors.initials: K
authors.lastname: Matsubayashi
authors.forename: T
authors.initials: T
authors.lastname: Nomoto
mesh_terms: D017545:Aortic Aneurysm, Thoracic / Q000601:surgery*; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001921:Brain / Q000378:metabolism*; D002423:Cause of Death; D002544:Cerebral Infarction / Q000209:etiology; D002560:Cerebrovascular Circulation; D003128:Coma / Q000209:etiology; D005260:Female; D005544:Forecasting; D006324:Heart Arrest, Induced; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D010101:Oxygen Consumption; D010477:Perfusion; D012044:Regression Analysis; D051437:Renal Insufficiency / Q000209:etiology; D012189:Retrospective Studies; D017694:Rewarming; D012449:Safety; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors; D016896:Treatment Outcome