Canadian Journal of Anesthesia

, 49:185

Baseline heart rate may predict hypotension after spinal anesthesia in prehydrated obstetrical patients

Obstetrical and Pediatric Anesthesia

Abstract

Purpose

Hypotension is the most frequent complication of spinal anesthesia in pregnant patients. This study was designed to identify patients at risk for postspinal hypotension based on preoperative vital signs before and after an orthostatic challenge.

Methods

Forty healthy women scheduled for elective Cesarean section were enrolled in this prospective trial. Blood pressure (BP) and heart rate (HR) were recorded with the patient in the lateral supine position and after standing up. After a bupivacaine spinal anesthetic, BP was obtained every two minutes for 30 min. Ephedrine treatment was administered based on the degree of hypotension observed. Hemodynamic parameters were correlated to ephedrine requirements (Spearman’s rank order correlation).

Results

There was a significant correlation in baseline maternal HR and ephedrine requirements (P = 0.005). The degree of orthostatic changes in mean arterial BP and HR did not correlate with postspinal hypotension.

Conclusions

Baseline HR may be predictive of obstetric spinal hypotension. Higher baseline HR, possibly reflecting a higher sympathetic tone, may be a useful parameter to predict postspinal hypotension.

La fréquence cardiaque initiale peut être prédictive d’hypotension après la rachianesthésie chez des patientes obstétricales préhydratées

Résumé

Objectif

Chez les femmes enceintes, l’hypotension est la plus fréquente complication de la rachianesthésie. Notre étude veut identifier les patientes à risque d’hypotension postsrachidienne en notant les signes vitaux d’avant et après la provocation orthostatique.

Méthode

Quarante femmes en bonne santé, devant subir une césarienne, ont participé à cet essai prospectif. La tension artérielle (TA) et la fréquence cardiaque (FC) ont été notées alors que la patiente est en décubitus latéral, puis en station debout. La TA a été enregistrée toutes les deux minutes pendant 30 min à la suite de l’administration rachidienne de bupivacaïne. De l’éphédrine a été donnée en fonction du degré d’hypotension observée. On a mis en corrélation les paramètres hémodynamiques et les besoins d’éphédrine (corrélation des rangs de Spearman).

Résultats

Une corrélation significative a été notée entre la FC de base et les besoins d’éphédrine (P = 0,005). Il n’y a pas eu de corrélation entre le degré des modifcations orthostatiques de la TA et de la FC moyennes et l’hypotension postrachidienne.

Conclusion

La FC initiale peut être prédictive d’hypotension rachidienne en obstétrique. Une FC initiale élevée, pouvant exprimer un tonus sympathique plus important, peut être un paramètre prédictif intéressant d’hypotension postrachidienne.

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Copyright information

© Canadian Anesthesiologists 2002

Authors and Affiliations

  1. 1.Departments of AnesthesiologyUniversity of Florida College of MedicineGainesvilleUSA
  2. 2.Departments of Obstetrics and GynecologyUniversity of Florida College of MedicineGainesvilleUSA
  3. 3.Department of AnesthesiologyGainesvilleUSA

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