title: Cerebral oximetry values in dialyzed surgical patients: a comparison between hemodialysis and peritoneal dialysis.
abstract: BACKGROUND
  Cerebral tissue regional oxygen saturation (rSO2) through near-infrared spectroscopy (NIRS) is a method for non-invasive monitoring of cerebral tissue oxygenation. However, nowadays there is limited information on the level of cerebral tissue oxygenation in dialyzed end-stage renal disease (ESRD) surgical patients. The aim of this observational study was to evaluate the baseline cerebral rSO2 values, to compare values between hemodialysis (HD) and peritoneal dialysis (PD) patients and identify risk factors that could predict cerebral tissue oxygenation in these patients.
  
  
  METHODS
  Thirty-two ESRD patients (≥18 years old), scheduled to undergo elective minor or major surgery, were enrolled. Patients were allocated in two groups according to dialysis modality. Twenty-three patients were treated with HD and nine were treated with PD. Demographic and clinical characteristics, comorbidities and arterial hemoglobin oxygen saturation (SpO2) of the study population were recorded.
  
  
  RESULTS
  Patients who were treated with HD had significant lower baseline rSO2 values compared with PD patients [median, 50% (28-63) vs. 63% (45-69), p = 0.002]. Hierarchical linear regression model analysis showed that preoperative Hb and SpO2 were positive predictive variables (B = 0.353, p = 0.01 and B = 0.375, p = 0.009, respectively) for rSO2. Moreover, dialysis modality was independent predictor for baseline rSO2. The modality of dialysis remained an independent predictor for rSO2 after controlling for the other significant variables (B = 0.291, p = 0.032) and PD was associated with higher baseline values of rSO2.
  
  
  CONCLUSIONS
  In conclusion, ESRD surgical patients undergoing PD treatment appear to have significantly higher baseline cerebral tissue saturation values compared with HD.
authors.affiliation: Department of Anesthesia and Postoperative Intensive Care, University Hospital of Ioannina, Ioannina, Greece.
authors.forename: Georgios
authors.initials: G
authors.lastname: Papadopoulos
authors.forename: Evangelia
authors.initials: E
authors.lastname: Dounousi
authors.forename: Athanasios
authors.initials: A
authors.lastname: Papathanasiou
authors.forename: Georgios
authors.initials: G
authors.lastname: Papathanakos
authors.forename: Petros
authors.initials: P
authors.lastname: Tzimas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010100:Oxygen / Q000502:physiology*; D010530:Peritoneal Dialysis; D057234:Preoperative Period; D006435:Renal Dialysis; D019265:Spectroscopy, Near-Infrared; D055815:Young Adult
chemical_list: D010100:Oxygen