Haemodynamic effects of glycopyrrolate pre-treatment before phenylephrine infusion during spinal anaesthesia for caesarean delivery

W. D. Ngan Kee, Wee Yee Shara Lee, K. S. Khaw, F. F. Ng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

17 Citations (Scopus)


Background Phenylephrine given during spinal anaesthesia for caesarean delivery often induces a decrease in heart rate which may decrease cardiac output. Anticholinergic drugs may be given to attenuate this effect but may also cause more labile blood pressure. This study evaluated the effects of glycopyrrolate pre-treatment on non-invasively measured cardiac output and accuracy of blood pressure control. Methods At induction of spinal anaesthesia for caesarean delivery, 104 patients randomly received intravenous glycopyrrolate 4 μg/kg or saline placebo. Systolic blood pressure, measured at 1-min intervals, was maintained near baseline using closed-loop feedback computer-controlled phenylephrine infusion with crystalloid cohydration. Cardiac output and stroke volume were measured using suprasternal Doppler ultrasonography at baseline and 5-min intervals for 20 min. Blood pressure control was assessed using performance error calculations. Results Eleven patients were excluded. Patients who received glycopyrrolate (n = 45) had greater cardiac output over time (P < 0.001), greater heart rate over time (P < 0.001), similar stroke volume over time (P = 0.95), and lower median phenylephrine infusion rate (P = 0.006) compared with control (n = 48). There was no difference in the incidence of hypotension between groups. Analysis of blood pressure control showed greater positive bias, greater inaccuracy and greater wobble in the glycopyrrolate group (all P < 0.05). Neonatal outcome was similar between groups. Conclusions Glycopyrrolate 4 μg/kg given at the start of a phenylephrine infusion increased heart rate and cardiac output but also decreased accuracy of blood pressure control, increased the incidence of hypertension and caused an increased incidence of dry mouth postoperatively compared with control.
Original languageEnglish
Pages (from-to)179-187
Number of pages9
JournalInternational Journal of Obstetric Anesthesia
Issue number3
Publication statusPublished - 1 Jul 2013
Externally publishedYes


  • Anaesthesia
  • Arterial blood pressure
  • Caesarean delivery
  • Caesarean section
  • Hypotension
  • Spinal

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine
  • Obstetrics and Gynaecology


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