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Effect of early versus delayed activation of thoracic epidural anesthesia on plasma pro-atrial natriuretic peptide to indicate deviations in central blood volume during esophagectomy
  1. Rune B Strandby1,
  2. Rikard Ambrus1,
  3. Michael P Achiam1,
  4. Jens P Goetze2,
  5. Niels H Secher3 and
  6. Lars B Svendsen1
  1. 1 Department of Surgical Gastroenterology, Rigshospitalet, Copenhagen, Denmark
  2. 2 Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
  3. 3 Department of Anesthesia, Rigshospitalet, Copenhagen, Denmark
  1. Correspondence to Dr Rune B Strandby, Department of Surgical Gastroenterology, Rigshospitalet, Copenhagen, Denmark; runestrandby{at}


Background and Objectives A side effect to thoracic epidural anesthesia (TEA) is hypotension induced by central hypovolemia. This study addressed whether early activation (EA) versus late activation (LA) of TEA affects plasma pro-atrial natriuretic peptide (proANP) reflecting deviations in the central blood volume (CBV). We hypothesized that EA TEA would reduce plasma proANP, thus reflecting a decrease in CBV.

Methods A randomized, controlled, single-blinded trial was conducted. Patients undergoing open esophagectomy were randomized to EA (n=25, after induction of general anesthesia) or LA TEA (n=25, after re-established gastric continuity) with the epidural catheter placed at the interspaces Th7-8 or Th8-9. Plasma proANP was determined repetitively along with hemodynamic variables and administration of fluid/vasopressors as postoperative complications were noted.

Results With EA TEA, plasma proANP decreased following induction of anesthesia to the end of surgery (13%; 113±68 to 99±49 pmol/L; p=0.026), but that was not the case in the LA group (3%; 97±44 to 94±49 pmol/L; p=0.565) despite equal fluid balance (+1584±582 vs +1560±563 mL; p=0.888). Accordingly, the EA group required excessive treatment with vasopressors to maintain MAP >60 mm Hg during surgery (2.7±2 vs 1.6±1.4 ephedrine boluses; p=0.033 and infusion of phenylephrine for 216±86 vs 58±91 min; p<0.001). Plasma proANP and fluid balance were correlated only for EA patients (r=0.44; 95% CI 0.04 to 0.91; p=0.033).

Conclusions EA TEA reduces plasma proANP indicating that CBV becomes affected. Based on a correlation between plasma proANP and fluid balance, a 2000 mL volume surplus of lactated Ringer’s solution is required to maintain plasma proANP stable during open esophagectomy.

  • anesthesia
  • epidural
  • surgical procedures
  • operative
  • atrial natriuretic factor
  • blood volume

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  • Contributors All authors contributed to the design, conception and planning of the study; interpretation of results; and gave final approval for publication. RA and RBS: perioperative monitoring of patients and acquisition of data. RBS: data analysis and draft of the article.

  • Funding This work was supported by Lundbeck Fonden (R230-2016-2727), Ehrenreich’s Fond, Gangstedfonden (A31738), and J.E. Ormstrup and G. Ormstrup’s Fond.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Data are available upon reasonable request.