title: Baseline cerebral oximetry values depend on non-modifiable patient characteristics.
abstract: OBJECTIVE
  The aim of the present study was to evaluate baseline regional cerebral oxygen saturation (rSO2) values and identify factors influencing preoperative rSO2 in elective minor surgery.
  
  
  METHODS
  Observational analysis post-hoc.
  
  
  METHODS
  Observational post-hoc analysis of data for the patient sample (n=50) of a previously conducted clinical trial in patients undergoing tumourectomy for breast cancer or inguinal hernia repair. Exclusion criteria included pre-existing cerebrovascular diseases, anaemia, baseline pulse oximetry <97% and low quality rSO2 sensor signals. Demographic data, comorbidities, and ASA physical status as well as height and weight were collected prospectively from all patients. Baseline rSO2 values were recorded while the patient breathed room air, using the INVOS 5100C monitor™ (Covidien, Dublin, Ireland).
  
  
  RESULTS
  Thirty-seven women (72%) and 13 men (28%) 48 ± 13 years of age were enrolled in this study. Baseline rSO2 was 62.01 ± 10.38%. Baseline rSO2 was significantly different between men (67.6 ± 11.2%) and women (60 ± 9.4%), (P=0.023). There were also differences between baseline rSO2 and ASA physical status (ASA I: 67.6 ± 10.7%, ASA II: 61.6 ± 8.4%, ASA III: 55.8 ± 13.9%, P=0.045). Baseline rSO2 had a positive correlation with body weight (r=0.347, P=0.014) and height (r=0.345, P=0.014). We also found significant differences in baseline rSO2 among patients with and without chronic renal failure (P=0.005). No differences were found in any other studied variables.
  
  
  CONCLUSIONS
  Non-modifiable patient characteristics (ASA physical status, sex, chronic renal failure, body weight and height) influence baseline rSO2.
authors.affiliation: Department of Anaesthesiology, Hospital Universitario de Gran Canaria Doctor Negrín, Barranco de la Ballena s/n, 35010 Las Palmas de Gran Canaria, Spain. Electronic address: ori98es@yahoo.es.
authors.forename: Lucía
authors.initials: L
authors.lastname: Valencia
authors.affiliation: Department of Anaesthesiology, Hospital Universitario de Gran Canaria Doctor Negrín, Barranco de la Ballena s/n, 35010 Las Palmas de Gran Canaria, Spain.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Rodríguez-Pérez
authors.affiliation: Department of Anaesthesiology, Hospital Universitario de Gran Canaria Doctor Negrín, Barranco de la Ballena s/n, 35010 Las Palmas de Gran Canaria, Spain.
authors.forename: Nazario
authors.initials: N
authors.lastname: Ojeda
authors.affiliation: Department of Traumatology, Hospital Universitario Insular de Gran Canaria, Las Palmas de Gran Canaria, Spain.
authors.forename: Romen Yone
authors.initials: RY
authors.lastname: Santana
authors.affiliation: Department of Anaesthesiology, Hospital Universitario de Gran Canaria Doctor Negrín, Barranco de la Ballena s/n, 35010 Las Palmas de Gran Canaria, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Morales
authors.affiliation: Department of Anaesthesiology, Hospital Universitario de Gran Canaria Doctor Negrín, Barranco de la Ballena s/n, 35010 Las Palmas de Gran Canaria, Spain.
authors.forename: Oto
authors.initials: O
authors.lastname: Padrón
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D001923:Brain Chemistry; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010092:Oximetry; D010100:Oxygen / Q000097:blood; D011300:Preoperative Care; D012016:Reference Values; D012727:Sex Characteristics; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Age; Cerebral oximetry; Near-infrared spectroscopy