title: A comparison of the effects of preanesthetic administration of crystalloid versus colloid on intrathecal spread of isobaric spinal anesthetics and cerebrospinal fluid movement.
abstract: BACKGROUND
  Movement of the cerebrospinal fluid (CSF) is one of the most important factors in determining the intrathecal spread of isobaric spinal anesthetics. Preanesthetic administration of either crystalloid or colloid immediately before spinal anesthesia (preload) may result in different CSF pulsatile movement because of their different physical properties. We examined whether preload of crystalloid versus colloid may have different effects on the intrathecal spread of isobaric spinal anesthetics as a result of their different CSF dynamics regarding its pulsatile movement.
  
  
  METHODS
  In a clinical study of isobaric spinal anesthesia, patients were allocated into 1 of 2 groups according to preload with either crystalloid (n = 30) or colloid (n = 30) before spinal anesthesia with 0.5 isobaric tetracaine. The pulsatile movements of CSF at the L2-3 intervertebral space and midportion of the aqueduct of Sylvius were also examined by magnetic resonance images in healthy volunteers (n = 23) at 0, 30, and 60 minutes after administering either crystalloid or colloid.
  
  
  RESULTS
  In the clinical study, the time to reach the peak sensory block level was delayed significantly in the crystalloid preload group (27.2 ± 17.8 minutes; P < 0.01) compared with the colloid preload group (13.9 ± 7.0 minutes). The median sensory block levels of the crystalloid preload group at 15 minutes (T10, P < 0.05) and 20 minutes (T9.5, P < 0.05) were significantly lower than those (T8, T7, respectively) of the colloid preload group. In the magnetic resonance imaging study, cranially directed CSF pulsatile movement decreased significantly at the L2-3 intervertebral intrathecal space at 30 minutes after crystalloid administration, but not after colloid administration. The CSF production rate significantly increased at 30 minutes (637 μL/min, P < 0.05) after crystalloid preload compared with the baseline measurement (448 μL/min), and then slightly decreased (609 μL/min) at 60 minutes. In the colloid preload group, the CSF production rate was not statistically significant compared with the baseline measurement (464, 512, and 542 μL/min at baseline, 30, and 60 minutes, respectively).
  
  
  CONCLUSIONS
  Compared with a colloid preload, which may be comparable to the no-preload condition, crystalloid preload prolonged the time to reach the peak sensory block level in isobaric spinal anesthesia, which might have been caused by a significant decrease in CSF pulsatile movement. This attenuated CSF pulsatile movement in the crystalloid preload group might have resulted from significant increases of CSF production.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-Dong, Kangnam-Ku, Seoul, 135-710 Korea.
authors.forename: Byung Seop
authors.initials: BS
authors.lastname: Shin
authors.forename: Chung Su
authors.initials: CS
authors.lastname: Kim
authors.forename: Woo Seok
authors.initials: WS
authors.lastname: Sim
authors.forename: Chul Joong
authors.initials: CJ
authors.lastname: Lee
authors.forename: Sung Tae
authors.initials: ST
authors.lastname: Kim
authors.forename: Gunn Hee
authors.initials: GH
authors.lastname: Kim
authors.forename: Si Ra
authors.initials: SR
authors.lastname: Bang
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Lee
authors.forename: Sun Ji
authors.initials: SJ
authors.lastname: Hyun
authors.forename: Gaab Soo
authors.initials: GS
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000775:Anesthesia, Spinal / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000134:cerebrospinal fluid / Q000493:pharmacokinetics; D002626:Chemistry, Pharmaceutical; D003102:Colloids / Q000008:administration & dosage* / Q000493:pharmacokinetics; D000077324:Crystalloid Solutions; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D007552:Isotonic Solutions / Q000008:administration & dosage* / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*; D013748:Tetracaine / Q000008:administration & dosage* / Q000134:cerebrospinal fluid / Q000493:pharmacokinetics; D013997:Time Factors; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D003102:Colloids; D000077324:Crystalloid Solutions; D007552:Isotonic Solutions; D013748:Tetracaine