title: Operating unit time use is associated with anaesthesia type in below-knee surgery in adults.
abstract: BACKGROUND
  Peripheral nerve blocks could reduce the operating unit and theatre time spent on high-risk patients who are particularly vulnerable to complications of general anaesthesia or have medications that prevent application of central neuraxial blocks.
  
  
  METHODS
  Medical record data of 617 and 254 elderly adults undergoing below-knee surgery in Jorvi and Meilahti hospitals (Helsinki University Hospital) between January 2010 and December 2012 were used to investigate the influence of anaesthetic technique on operating theatre times and on operating unit times using flexible parametric survival models. We report operating theatre and unit exit ratios (i.e. hazard ratios but using ratios of exit rates) for different types of anaesthesia.
  
  
  RESULTS
  Adjusted analyses: In Jorvi Hospital, anaesthesia type was associated with large initial differentials in operating theatre times. The theatre exit ratios remained lower for general anaesthesia and central neuraxial blocks compared to peripheral nerve blocks until 30 min. In Meilahti Hospital, anaesthesia type did not influence theatre time, but was the best predictor of operating unit times. Compared to peripheral nerve blocks, the exit ratio remained lower for general anaesthesia until five operating unit hours in both hospitals and for central neuraxial blocks until 1 h in Meilahti Hospital and until 3 h in Jorvi Hospital. Holding area was used more in Jorvi Hospital compared to Meilahti Hospital.
  
  
  CONCLUSIONS
  Peripheral nerve block anaesthesia reduces time spent in the operating unit and can reduce time spent in the operating theatre if induced in holding area outside of theatre.
authors.affiliation: Division of Anaesthesiology, Department of Anaesthesiology, Intensive Care and Pain Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.|Department of Public Health, University of Helsinki, Helsinki, Finland.
authors.forename: T J
authors.initials: TJ
authors.lastname: Lohela
authors.affiliation: Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: R P
authors.initials: RP
authors.lastname: Chase
authors.affiliation: Division of Anaesthesiology, Department of Anaesthesiology, Intensive Care and Pain Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors.forename: T A
authors.initials: TA
authors.lastname: Hiekkanen
authors.affiliation: Division of Anaesthesiology, Department of Anaesthesiology, Intensive Care and Pain Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors.forename: V K
authors.initials: VK
authors.lastname: Kontinen
authors.affiliation: Division of Anaesthesiology, Department of Anaesthesiology, Intensive Care and Pain Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors.forename: M J
authors.initials: MJ
authors.lastname: Hynynen
mesh_terms: D000758:Anesthesia / Q000379:methods*; D000768:Anesthesia, General; D006801:Humans; D009407:Nerve Block; D009873:Operating Rooms; D013997:Time Factors