Korean J Anesthesiol.  2011 Dec;61(6):482-487. 10.4097/kjae.2011.61.6.482.

Hemodynamic effects of continuous intravenous injection and bolus plus continuous intravenous injection of oxytocin in cesarean section

• Kim TS
• Bae JS
• Park JM
• Kang SK

• KMID: 1854061
• DOI: http://doi.org/10.4097/kjae.2011.61.6.482

Abstract

BACKGROUND
Oxytocin may cause adverse cardiovascular effects, including tachycardia and hypotension, whereas the optimal dose of oxytocin at elective cesarean section is unclear. To determine the lowest effective dose of oxytocin, we studied the hemodynamic effects of three doses during spinal anesthesia for elective single cesarean delivery.
METHODS
Sixty women received oxytocin by continuous (0.5 IU/min) or bolus-continuous (2 or 5 IU prior to 0.25 IU/min continuous intravenous injection) intravenous injection after clamping of the umbilical cord. We compared changes in heart rate (HR), mean arterial pressure (MAP) and estimated blood loss (EBL). Uterine tone (UT) was assessed by palpation on a linear analog scale (LAS) at 5, 10, 15, 20 and 25 minutes after the oxytocin injection. In addition, oxytocin-related side-effects such as nausea and vomiting were recorded.
RESULTS
Marked hemodynamic changes such as HR and MAP occurred in the bolus-continuous groups but not in the continuous groups. Although we were not able to observe a variation of EBL in each group, the UT significantly increased in the bolus-continuous groups when compared with that the continuous groups. In addition, the hemodynamic changes such as HR and MAP were lower in the two IU bolus-continuous group than those in the five IU group.
CONCLUSIONS
Although bolus-continuous injection of oxytocin resulted in more hemodynamic changes than continuous injection, bolus-continuous injection had a greater effect on uterine contraction. Furthermore, two IU bolus-continuous injection showed lower hemodynamic changes than in the five IU bolus-continuous injection.

Keyword

Bolus-continuous intravenous injection; Continuous intravenous injection; Elective cesarean section; Oxytocin; Spinal anesthesia

MeSH Terms

Anesthesia, Spinal
Arterial Pressure
Cesarean Section
Constriction
Female
Heart Rate
Hemodynamics
Humans
Hypotension
Injections, Intravenous
Nausea
Oxytocin
Palpation
Pregnancy
Tachycardia
Umbilical Cord
Uterine Contraction
Vomiting
Oxytocin