title: Haemodynamics and cerebral oxygenation during arthroscopic shoulder surgery in beach chair position under general anaesthesia.
abstract: BACKGROUND
  Patients undergoing surgery in beach chair position (BCP) are at risk of cerebral ischaemia. We determined the prevalence and risk factors of jugular venous bulb oxygen desaturation (SjvO(2)  < 50%) in BCP. It was also examined whether regional cerebral tissue oxygen saturation (SctO(2) ) measured by near-infrared spectroscopy and SjvO(2)  are interchangeable for assessment of cerebral oxygenation.
  
  
  METHODS
  Fifty-six consecutive patients undergoing arthroscopic shoulder surgery in BCP were studied. Anaesthesia was intravenous with propofol and remifentanil (P/R) or inhalational with sevoflurane and 50% nitrous oxide (S/N) depending on provider choice. Mean arterial pressure (MAP), heart rate (HR), SjvO(2) , and SctO(2)  were measured before (baseline; post-induction in supine position) and after the patients assumed BCP. Bland-Altman analysis was performed to measure the agreement between SctO(2)  and SjvO(2) .
  
  
  RESULTS
  SjvO(2) , SctO(2) , MAP, and HR decreased significantly when patients were raised into BCP. Jugular desaturation occurred in 41% of patients (56% with P/R vs. 21% with S/N anaesthesia, P = 0.0077). Risk factors for the desaturation included P/R anaesthesia [adjusted odds ratio (aOR) 4.76, 95% confidence interval (CI) 1.34-16.95, P = 0.016] and MAP < 50 mmHg (aOR 3.85, 95% CI 1.21-12.25, P = 0.023). Bland-Altman analysis showed a mean difference of -8.9% with 95% limit of agreement between -40.0% and 23.0%. The percentage error [1.96 standard deviation/mean of the reference method] was 48.5%.
  
  
  CONCLUSIONS
  The incidence of jugular desaturation in BCP was 41%, and P/R anaesthesia and hypotension were associated with its occurrence while undergoing surgery under general anaesthesia. SctO(2)  may not replace SjvO(2)  for the determination of cerebral oxygenation.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, South Korea.
authors.forename: H
authors.initials: H
authors.lastname: Jeong
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
authors.forename: E A
authors.initials: EA
authors.lastname: Jang
authors.forename: S S
authors.initials: SS
authors.lastname: Chung
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.forename: K Y
authors.initials: KY
authors.lastname: Yoo
mesh_terms: D000368:Aged; D000768:Anesthesia, General / Q000009:adverse effects*; D000769:Anesthesia, Inhalation / Q000009:adverse effects; D000771:Anesthesia, Intravenous / Q000009:adverse effects; D018685:Anesthetics, Inhalation / Q000009:adverse effects / Q000494:pharmacology; D018686:Anesthetics, Intravenous / Q000009:adverse effects* / Q000494:pharmacology; D001182:Arthroscopy; D001921:Brain / Q000378:metabolism*; D017558:Elective Surgical Procedures; D005260:Female; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007022:Hypotension / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D002534:Hypoxia, Brain / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D007431:Intraoperative Complications / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D007601:Jugular Veins; D008297:Male; D008738:Methyl Ethers / Q000009:adverse effects / Q000494:pharmacology; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009609:Nitrous Oxide / Q000009:adverse effects / Q000494:pharmacology; D010092:Oximetry; D010100:Oxygen / Q000097:blood / Q000378:metabolism*; D010880:Piperidines / Q000009:adverse effects* / Q000494:pharmacology; D011187:Posture / Q000502:physiology*; D015742:Propofol / Q000009:adverse effects* / Q000494:pharmacology; D000077208:Remifentanil; D000077149:Sevoflurane; D012785:Shoulder Joint / Q000601:surgery*
chemical_list: D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008738:Methyl Ethers; D010880:Piperidines; D000077149:Sevoflurane; D009609:Nitrous Oxide; D000077208:Remifentanil; D010100:Oxygen; D015742:Propofol