title: The sitting position during neurosurgical procedures does not influence serum biomarkers of pulmonary parenchymal injury.
abstract: BACKGROUND
  The sitting position during neurosurgical operations predisposes to air penetration through veins and the movement of the air through the pulmonary circulation. Contact of an air bubble with the endothelium can lead to acute lung injury. The presence of specific pulmonary proteins in the plasma such as surfactant protein D (SP-D) and Clara cell protein (CC16) is a biomarker of damaging processes at the air-blood barrier. The aim of our study was to examine the hypothesis that the level of investigated pulmonary biomarkers in plasma is higher in patients operated on in the sitting position.
  
  
  METHODS
  The study included patients undergoing planned neurosurgical operations, who were divided into two groups: the sitting group (40 patients, operated on in the sitting position) and the supine group (24 patients, operated in the supine position). After the operation blood samples were drawn, centrifuged, frozen and stored until analyses were conducted. The determination of the SP-D and CC16 levels was performed using an ELISA test. Air embolism (VAE) was defined as a sudden drop in etCO2 of more than 2 mmHg and the presence of air bubbles in the aspirated blood from the central cannula. In all patients, the number of hospitalization days in the postoperative period was calculated.
  
  
  RESULTS
  There were no differences in the average levels of SP-D between the groups (the mean in the sitting group was 95.56 ng/mL and the mean in the supine group was 101.21 ng/mL). The average levels of CC16 were similar in both groups as well (6.56 ng/mL in the sitting group and 6.79 ng/mL in the supine group). There was a statistically significant positive correlation between SP-D and CC16 values in both groups. VAE was diagnosed clinically in 12.5% of cases in the sitting group without a significant increase in SP-D and CC16 levels. On average, patients in both groups were discharged from the hospital within 9 days of surgery.
  
  
  CONCLUSIONS
  The sitting position and intraoperative VAE during neurosurgical procedures do not affect the concentration of plasma biomarkers of pulmonary parenchymal injury such as SP-D and CC16.
authors.affiliation: Department of Anesthesiology and Intensive Care, Medical University of Silesia, Medykow 14, Katowice, 40-75, Poland. izaduda@neostrada.pl
authors.forename: Izabela
authors.initials: I
authors.lastname: Duda
authors.forename: Konstancja
authors.initials: K
authors.lastname: Grzybowska
authors.forename: Halina
authors.initials: H
authors.lastname: Jędrzejowska-Szypułka
authors.forename: Joanna
authors.initials: J
authors.lastname: Lewin-Kowalik
mesh_terms: D055371:Acute Lung Injury / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D004618:Embolism, Air / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D056888:Patient Positioning; D011446:Prospective Studies; D037663:Pulmonary Surfactant-Associated Protein D / Q000097:blood*; D014598:Uteroglobin / Q000097:blood*
chemical_list: D015415:Biomarkers; D037663:Pulmonary Surfactant-Associated Protein D; C556389:SCGB1A1 protein, human; D014598:Uteroglobin