Heart rate variability as a predictor of hypotension following spinal for elective caesarean section: a prospective observational study

Anaesthesia. 2017 May;72(5):603-608. doi: 10.1111/anae.13813. Epub 2017 Jan 30.


Post-spinal hypotension remains a common and clinically-important problem during caesarean section, and accurate pre-operative prediction of this complication might enhance clinical management. We conducted a prospective, single-centre, observational study of heart rate variability in 102 patients undergoing elective caesarean section in a South African regional hospital. We performed Holter recording for ≥ 5 min in the hour preceding spinal anaesthesia. The low-frequency/high-frequency ratio component of heart rate variability was compared, using a logistic regression model, with baseline heart rate and body mass index (BMI) as a predictor of hypotension (defined as systolic arterial pressure < 90 mmHg) occurring from the time of spinal insertion until 15 min after delivery of the baby. We also assessed clinically relevant cut-point estimations for low-frequency/high-frequency ratio. Low-frequency/high-frequency ratio predicted hypotension (p = 0.046; OR 1.478, 95%CI 1.008-1.014), with an optimal cut-point estimation of 2.0; this threshold predicted hypotension better than previously determined thresholds (p = 0.003; c-statistic 0.645). Baseline heart rate (p = 0.20; OR 1.022, 95%CI 0.988-1.057) and BMI (p = 0.60; OR 1.017, 95%CI 0.954-1.085) did not predict hypotension. Heart rate variability analysis is a potentially useful clinical tool for the prediction of hypotension. Future studies should consider a low-frequency/high-frequency ratio threshold of 2.0 for prospective validation.

Keywords: caesarean section; heart rate variability; obstetric; prediction; spinal hypotension.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Anesthesia, Obstetrical / adverse effects*
  • Anesthesia, Spinal / adverse effects*
  • Blood Pressure / drug effects
  • Body Mass Index
  • Cesarean Section / methods*
  • Electrocardiography, Ambulatory
  • Female
  • Heart Rate / drug effects*
  • Humans
  • Hypotension / diagnosis*
  • Hypotension / etiology*
  • Infant, Newborn
  • Predictive Value of Tests
  • Pregnancy
  • Prognosis
  • Prospective Studies