title: Assessment of endothelial glycocalyx disruption in term parturients receiving a fluid bolus before spinal anesthesia: a prospective observational study.
abstract: Fluid bolus administration is a standard treatment for hypotension. However, the effectiveness of the traditional prophylactic bolus in parturients undergoing spinal anesthesia for cesarean delivery has been questioned. One potential mechanism for the failure of a prophylactic fluid bolus to prevent hypotension is hypervolemia-induced destruction of the endothelial glycocalyx, a structure that plays a vital role in regulating intravascular fluid shifts.
  
  
  
  Thirty healthy parturients undergoing elective cesarean delivery under spinal anesthesia were recruited. Known endothelial glycocalyx biomarkers, heparan sulfate and syndecan-1 along with atrial natriuretic peptide, were measured before and after a 750-mL crystalloid fluid bolus. Cardiac performance parameters, cardiac index and systemic vascular resistance, were monitored during the fluid bolus using thoracic-impedance cardiography.
  
  
  
  A significant increase in both heparan sulfate 96 ng/mg (P=0.0098) and syndecan-1 2.4 ng/mg (P=0.045) were observed after the fluid bolus. There was a non-significant increase in atrial natriuretic peptide 0.6 pg/mg (P=0.293). Cardiac parameters showed a small but significant change; over an average of 15 min, cardiac index increased by 0.1L/min/m2 (P=0.0005) and systemic vascular resistance decreased by 30.7 dyn.s/cm5 (P=0.0025).
  
  
  
  A prophylactic fluid bolus in parturients undergoing spinal anesthesia for cesarean delivery disrupts the endothelial glycocalyx, as noted by a statistically significant increase in post-bolus heparan sulfate and syndecan-1 levels. Although studied in the past, atrial natriuretic peptide could not explain this disruption. Our fluid bolus did not have a clinically relevant effect on cardiac performance.
authors.affiliation: Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL, USA. Electronic address: powelma@uab.edu.
authors.forename: M F
authors.initials: MF
authors.lastname: Powell
authors.affiliation: Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: M
authors.initials: M
authors.lastname: Mathru
authors.affiliation: Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: A
authors.initials: A
authors.lastname: Brandon
authors.affiliation: Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: R
authors.initials: R
authors.lastname: Patel
authors.affiliation: Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Frölich
mesh_terms: D000328:Adult; D000773:Anesthesia, Obstetrical / Q000009:adverse effects* / Q000379:methods*; D000775:Anesthesia, Spinal / Q000009:adverse effects* / Q000379:methods*; D009320:Atrial Natriuretic Factor / Q000378:metabolism; D002585:Cesarean Section; D004730:Endothelium, Vascular / Q000473:pathology*; D005260:Female; D005440:Fluid Therapy / Q000009:adverse effects* / Q000379:methods*; D019276:Glycocalyx / Q000473:pathology*; D006497:Heparan Sulfate / Q000097:blood; D006801:Humans; D007022:Hypotension / Q000628:therapy; D011247:Pregnancy; D011446:Prospective Studies; D053668:Syndecan-1 / Q000097:blood
chemical_list: D009320:Atrial Natriuretic Factor; D006497:Heparan Sulfate; D053668:Syndecan-1
keywords: Cesarean delivery; Endothelial glycocalyx; Spinal hypotension; Volume loading