title: Venous air embolism in the sitting position in cranial neurosurgery: incidence and severity according to the used monitoring.
abstract: There is an ongoing debate about the sitting position (SP) in neurosurgical patients. The SP provides a number of advantages as well as severe complications such as commonly concerning venous air embolism (VAE). The best monitoring system for the detection of VAE is still controversial.
  
  
  
  In this retrospective analysis we compared 208 patients. Transesophageal echocardiography (TEE) or transthoracic Doppler (TTD) were used as monitoring devices to detect VAE; 101 cases were monitored with TEE and 107 with TTD.
  
  
  
  The overall incidence of VAE was 23% (TTD: 10%; TEE: 37%), but the incidence of clinically relevant VAE (drop in end-tidal carbon dioxide above 3 mmHg) was higher in the TTD group (9 out of 17 VAE, 53%) compared to the TEE group (19 out of 62 VAE, 31%). None of the patients with recorded VAE had clinically significant sequelae.
  
  
  
  In this small sample we found more VAE events in the TEE group, but the incidence of clinically relevant VAE was rare and comparable to other data. There is no consensus in the definition of clinically relevant VAE.
authors.affiliation: Department of Anaesthesiology and Intensive Care, Medical School Hannover (OE8050), Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Günther
authors.affiliation: Department of Anaesthesiology and Intensive Care, Medical School Hannover (OE8050), Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Frank
authors.affiliation: Department of Neurosurgery, Medical School Hannover, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Makoto
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Department of Neurosurgery, Medical School Hannover, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Elvis Josef
authors.initials: EJ
authors.lastname: Hermann
authors.affiliation: Department of Anaesthesiology and Intensive Care, Medical School Hannover (OE8050), Carl-Neuberg-Straße 1, 30625, Hannover, Germany. palmaers.thomas@mh-hannover.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Palmaers
mesh_terms: D000328:Adult; D000368:Aged; D002550:Cerebral Veins / Q000473:pathology / Q000601:surgery; D003399:Craniotomy / Q000009:adverse effects* / Q000379:methods; D017548:Echocardiography, Transesophageal / Q000379:methods; D004618:Embolism, Air / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D056888:Patient Positioning / Q000009:adverse effects* / Q000379:methods
keywords: Neurosurgery; Semi-sitting position; Sitting position; Transesophageal echocardiography; Transthoracic Doppler; Venous air embolism