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

Pharmacokinetics and safety of inhaled oxytocin compared with intramuscular oxytocin in women in the third stage of labour: A randomized open-label study

AIMS

To compare pharmacokinetics (PK) and safety of heat-stable inhaled (IH) oxytocin with intramuscular (IM) oxytocin in women in third stage of labour (TSL), the primary endpoint being PK profiles of oxytocin IH and secondary endpoint of safety.

METHODS

A phase 1, randomized, cross-over study was undertaken in 2 UK and 1 Australian centres. Subjects were recruited into 2 groups: Group 1, women in TSL; Group 2, nonpregnant women of childbearing potential (Cohort A, combined oral contraception; Cohort B, nonhormonal contraception). Participants were randomized 1:1 to: Group 1, oxytocin 10 IU (17 μg) IM or oxytocin 240 IU (400 μg) IH immediately after delivery; Group 2, oxytocin 5 IU (8.5 μg) intravenously and oxytocin 240 IU (400 μg) IH at 2 separate dosing sessions.

RESULTS

Participants were recruited between 23 November 2016 to 4 March 2019. In Group 1, 17 participants were randomized; received either IH (n = 9) or IM (n = 8) oxytocin. After IH and IM administration, most plasma oxytocin concentrations were below quantification limits (2 pg/mL). In Group 2 (n = 14), oxytocin IH concentrations remained quantifiable ≤3 h postdose. Adverse events were reported in both groups, with no deaths reported: Group 1, IH n = 3 (33%) and IM n = 2 (25%); Group 2, n = 14 (100%).

CONCLUSION

Safety profiles of oxytocin IH and IM were similar. However, PK profiles could not be established for oxytocin IH or IM in women in TSL, despite using a highly sensitive and specific assay.

Intravenous oxytocin regimens in patients undergoing cesarean delivery: a systematic review and network meta-analysis of cluster-based groups

Information on evaluations of different oxytocin regimens used to prevent post-partum hemorrhage during cesarean delivery is scarce, and there is a lack of statistically pooled results for comparative doses. In this review, we aimed to analyze the effectiveness of different oxytocin regimens used and rank them accordingly. We performed a meta-analysis of randomized controlled trials (RCTs) reporting the incidence of additional uterotonic (AUT) use or amount of blood loss during cesarean delivery, where different oxytocin regimens were compared. Cluster analysis was used to define different clusters of oxytocin therapy based on the identified variable regimens. During the frequentist network meta-analysis, all clusters were compared to bolus clusters of dose range 3-5 IU. Data from 33 RCTs (6741 patients) to 26 RCTs (5422 patients) were assessed for AUT use and blood loss, respectively. Pairwise meta-analysis revealed a significant reduction in the use of AUTs or blood loss was recorded for bolus-infusion combination regimens. The network meta-analysis found that combined bolus-infusion regimens of (i) 3-5 IU and 0.25-1 IU/min or (ii) 3-5 IU and < 0.25 IU/min had statistically significant results for lowest consumption of AUTs (Ranks 1 and 2, respectively); whereas with the latter's use, the lowest blood loss (Rank 2) was observed. In contrast, the dose range, > 5 IU regimen was associated with higher side effects (lowest rank). During cesarean delivery, a significant reduction in the use of AUTs or blood loss (Rank 2) was recorded for bolus-infusion combination regimens. High doses did not have enough evidence to draw meaningful conclusions.

Cohort Study Summary of the Effects of Carboprost Tromethamine Combined with Oxytocin on Infant Outcome, Postpartum Hemorrhage and Uterine Involution of Parturients Undergoing Cesarean Section

Background

Carboprost tromethamine injection has a high safety factor in clinical application and has a good effect on uterine smooth muscle and vasoconstriction. Carboprost aminobutyriol combined with oxytocin may be beneficial to infant outcome and uterine involution after cesarean section.

Objective

To investigate the effects of carboprost tromethamine combined with oxytocin on infant outcome, postpartum hemorrhage, and uterine involution in parturients undergoing cesarean section.

Methods

A total of 120 parturients undergone cesarean section in our hospital from February 2019 to April 2021 were selected as the object of study. The parturients were randomly divided into control group (n = 60) and research group (n = 60). The control group was treated with oxytocin, and the research group was treated with carboprost aminobutyriol combined with oxytocin. The amount of maternal bleeding, uterine floor decline index, the end of lochia, poor rate of uterine involution, infant outcome, and the incidence of adverse drug reactions were compared between the two groups.

Results

The amount of bleeding in the research group was significantly lower than that in the control group (P < 0.05). The position of the last uterine floor and the index of uterine floor downward movement in the research group were significantly higher than those in the control group (P < 0.05). The disappearance time of bloody lochia and serous lochia in the research group was significantly shorter than that in the control group (P < 0.05). The end time of lochia in the research group was higher than that in the control group, and the rate of uterine involution in the research group was lower than that in the control group (P < 0.05). The neonatal weight and Apgar score in the research group were higher than those in the control group, and the hospitalization rate of neonatal ICU in the research group was significantly lower than that in the control group. The incidence of adverse reactions in the research group was significantly lower than that in the control group (P < 0.05).

Conclusion

Carboprost aminobutyriol combined with carbestatin can effectively prevent the occurrence of bleeding after cesarean section, improve uterine involution, and improve neonatal birth quality, which is worth popularizing.

Intravenous oxytocin dosing regimens for postpartum hemorrhage prevention following cesarean delivery: a systematic review and meta-analysis

OBJECTIVE

To compare the available evidence on intravenous oxytocin dosing regimens for the prevention of postpartum hemorrhage following cesarean delivery.

DATA SOURCES

We searched Ovid MEDLINE, Embase, Global Index Medicus, Cumulative Index of Nursing and Allied Health Literature, Cochrane Controlled Register of Trials, ClinicalTrials.gov, and the International Clinical Trials Registry Platform for eligible studies published until February 2020.

STUDY ELIGIBILITY CRITERIA

We included any randomized or nonrandomized study published in peer-reviewed journals that compared at least 2 different dosing regimens of intravenous oxytocin for postpartum hemorrhage prevention in women undergoing cesarean delivery.

METHODS

Two authors independently assessed the eligibility of studies, extracted the data, and assessed the risk of bias. The primary outcome was incidence of postpartum hemorrhage ≥1000 mL. Other review outcomes included use of additional uterotonics, blood loss, and adverse maternal events. Data were analyzed according to the type of intravenous administration (bolus only, infusion only, or bolus plus infusion) and total oxytocin dose. A meta-analysis was performed on randomized trials and the results were reported as risk ratios or mean differences with 95% confidence intervals. The Grading of Recommendations, Assessment, Development, and Evaluations scale was used to rate the certainty of evidence. Findings from dose-finding trials and nonrandomized studies were reported narratively.

RESULTS

A total of 35 studies (7333 women) met our inclusion criteria and included 30 randomized trials and 5 nonrandomized studies. There were limited data available from the trials for most outcomes, and the results were not conclusive. Compared with bolus plus infusion regimens, bolus only regimens probably result in slightly higher mean blood loss (mean difference, 52 mL; 95% confidence interval, 0.4-104 mL; moderate certainty). Among the bolus plus infusion regimens, initial bolus doses <5 IU may reduce nausea (risk ratio, 0.26; 95% confidence interval, 0.11-0.63; low certainty) when compared with doses of 5-9 IU. Total oxytocin doses of 5-9 IU vs total doses of 10-19 IU may increase the use of additional uterotonics (risk ratio, 13.00; 95% confidence interval, 1.75-96.37; low certainty). Effects on other outcomes were generally inconclusive.

CONCLUSION

There are limited data available for comparisons of IV oxytocin regimens for postpartum hemorrhage prevention following cesarean delivery. Bolus plus infusion regimens may lead to minor reductions in mean blood loss and initial bolus doses of <5 IU may minimize nausea. Bolus only regimens of 10 IU vs bolus only regimens of 5 IU may decrease the need for additional uterotonics, however, further comparative trials are required to understand the effects on other key outcomes, particularly hypotension.

Effect of intrathecal fentanyl on the incidence, severity, and duration of postdural puncture headache in parturients undergoing caesarean section: A randomised controlled trial

Background and Aims:

Postdural puncture headache (PDPH) is a side effect of spinal anaesthesia (SA). This study was conducted to investigate the effect of intrathecal fentanyl on the incidence, severity, and duration of PDPH.

Methods:

This was a prospective randomised controlled study including 220 parturients, who underwent Caesarean section (CS). They were divided into two groups for administration of SA with bupivacaine (bupivacaine group [B0], n = 111) or bupivacaine with fentanyl (bupivacaine fentanyl group [BF], n = 109). Haemodynamics, quality of anaesthesia, maternal side effects, and postoperative analgesia were noted. The neonatal Apgar score was recorded. The patients were followed up for 14 days after CS for the occurrence of PDPH, and its severity and duration. The collected data were statistically analysed, using the Statistical Package for the Social Sciences software version 25.

Results:

Regarding haemodynamics, heart rate increased at 5 min post-induction and blood pressure decreased at 2min post-induction in both groups. Excellent intraoperative anaesthesia was obtained in 91.7% and 79.3% of cases in groups BF and B0, respectively (P < 0.01). Longer duration of postoperative analgesia was present in the BF group as compared to the B0 group (P < 0.001). The incidence of PDPH decreased in the BF group in a non-significant manner, whereas its severity and duration increased significantly in the B0 group.

Conclusion:

Although the addition of intrathecal fentanyl to bupivacaine for SA in CS patients did not reduce the incidence of PDPH significantly, its severity and duration decreased significantly.

Hemodynamic effects of carbetocin administered as an intravenous bolus or infusion during cesarean delivery

Background

Postpartum hemorrhage is the leading cause of maternal mortality. Oxytocin being the most popular uterotonic agent, has been routinely administered after both vaginal delivery and cesarean section. Carbetocin is a newer uterotonic agent and provides the benefit of a longer duration of action without additional administration post-delivery.

Methods

We recruited 34 women undergoing elective cesarean section under spinal anesthesia. All patient was received spinal anesthesia using 0.5% hyperbaric Marcaine 8–10 mg in conjugation with fentanyl 20 μg in the left lateral decubitus position. Hartmann’s solution 10–15 ml/kg was administered before carbetocin. The operation started as soon as sensory block at level T4–T6 was confirmed. A non-invasive hemodynamic monitoring cuff (Finometer^®) was attached to the patient’s finger soon after the induction of spinal anesthesia. Using the Finometer, we recorded the heart rate and mean arterial pressure at every 15 s, starting from 15 s before the administration of carbetocin to 5 min after. After the removal of the placenta, the bolus group was administered intravenous bolus injection of carbetocin 100 μg and the infusion group was administered carbetocin 100 μg diluted in 50 ml normal saline, over 5 min using an infusion pump.

Results

The demographic data showed no significant difference between the two groups. Furthermore, there were no significant hemodynamic differences between the two groups.

Conclusions

The method of administration of carbetocin does not influence its hemodynamic effects.

Effect of a High-Rate Versus a Low-Rate Oxytocin Infusion for Maintaining Uterine Contractility During Elective Cesarean Delivery: A Prospective Randomized Clinical Trial

BACKGROUND

Oxytocin is routinely used as prophylaxis against uterine atony. During elective cesarean delivery (CD), an oxytocin bolus is used to initiate adequate uterine tone, followed by an oxytocin infusion to maintain uterine contractility. However, it is unclear whether oxytocin maintenance infusion rate influences total estimated blood loss (EBL).

METHODS

We performed a prospective, randomized, double-blind trial in 51 women undergoing elective CD. Women were randomly assigned to receive an oxytocin maintenance infusion of 2.5 or 15 U/h. All women received an oxytocin 1 U bolus to initiate adequate uterine tone. The primary outcome was EBL. EBL values between groups were compared using a Mann-Whitney U test; P < .05 as statistically significant. The median EBL difference with 95% confidence intervals was also calculated. Secondary outcomes included adequacy of uterine tone, use of additional uterotonics, and oxytocin-related side effects, including hypotension.

RESULTS

Of 51 women, 24 received a low-rate infusion and 27 received a high-rate infusion. Median (interquartile range) EBL values in the low-rate and high-rate groups were 634 (340-886) mL versus 512 (405-740) mL, respectively (P = .7). The median difference in EBL between groups was 22 mL; 95% confidence interval = -158 to 236 mL. The rate of postpartum hemorrhage did not differ between groups (low-rate group: 4/24 [16.7%] versus high-rate group: 4/26 [15.4%]). There were no between-group differences over time (first 20 minutes after commencing infusion) in the incidence of adequate uterine tone (P = .72) or hypotension (P = .32).

CONCLUSIONS

Among women undergoing elective CD receiving an oxytocin maintenance infusion, EBL and uterine tone did not differ between women receiving 2.5 U/h oxytocin and those receiving 15 U/h oxytocin. Our findings suggest that efficacy can be obtained with a low oxytocin maintenance infusion rate; however, dose-finding studies are needed to determine the infusion rate that optimizes drug efficacy while minimizing side effects.