title: Different injection techniques in the assessment of central haemodynamics in patients with cirrhosis.
abstract: OBJECTIVE
  Patients with cirrhosis often present with an abnormal distribution of blood volume with a reduced central blood volume (CBV) and central circulation time (CCT). In this group of patients it is important to determine the central haemodynamics as accurately as possible. The purpose of the present study was to compare an alternative injection technique by injecting technetium-labelled human serum albumin ((99m)Tc-HSA) from a deposit within the catheter lumen with the conventional injection technique by injecting iodine-labelled human serum albumin ((125)I-HSA) directly from a syringe.
  
  
  METHODS
  In 192 patients with cirrhosis, CCT, CBV, and cardiac output (CO) were determined according to kinetic principles. Injection of the two radiolabelled HSA were performed simultaneously and followed by arterial blood sampling every second for the first minute.
  
  
  RESULTS
  CCT was significantly shorter, and CO and CBV were significantly lower when determined by the alternative catheter deposit injection technique compared to determination by the traditional syringe deposit injection technique. The mean difference (bias) between CCT measured with the two methods was 0.38 s with limits of agreement ranging from - 0.83 s to 1.59 s.
  
  
  CONCLUSIONS
  This study demonstrates that different injection techniques result in a minor but significant difference of the measured haemodynamics. When highly accurate measurements of the central haemodynamics are needed, we recommend using the alternative injection technique by injection of the indicator from a deposit within the catheter in order to reduce overestimation of CCT.
authors.affiliation: Centre of Functional Imaging and Research, Department of Clinical Physiology, Hvidovre Hospital, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Tine N
authors.initials: TN
authors.lastname: Christensen
authors.forename: Christian
authors.initials: C
authors.lastname: Mortensen
authors.forename: Jens H
authors.initials: JH
authors.lastname: Henriksen
authors.forename: Søren
authors.initials: S
authors.lastname: Møller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007267:Injections / Q000379:methods*; D008103:Liver Cirrhosis / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012709:Serum Albumin / Q000008:administration & dosage*; D013667:Technetium / Q000008:administration & dosage; D055815:Young Adult
chemical_list: D012709:Serum Albumin; D013667:Technetium