Pulse wave analysis by digital photoplethysmography to record maternal hemodynamic effects of spinal anesthesia, delivery of the baby, and intravenous oxytocin during cesarean section

Changes in Compression Pressure of Elastic Stockings for the Lower Limbs During Cesarean Section: A Prospective Observational Study

Background Postpartum peripheral nerve injuries can impact recovery. Elastic stockings are recommended for thromboembolism prevention, although concerns about entrapment neuropathy exist. In this prospective observational study, we investigated the differential compressions caused by wearing elastic stockings before and after anesthesia, as well as changes in the diameters of the lower leg and ankle in parturient women undergoing spinal anesthesia for elective cesarean section (CS). Methods Eighteen pregnant women, classified by the American Society of Anesthesiologists as having physical status 2, underwent lower leg measurements taken before a CS. Elastic stockings were applied, and compression pressure was measured at pre-anesthesia, post-surgery, and six hours post-return to a hospital room. Fluid, blood loss, urine output, and neuropathy presence were recorded. For all parameters, changes at the three time points were compared for the primary analysis. For secondary analysis, participants were categorized as having intraoperative blood loss greater than (group P) or less than 1,000 g (group N), and factors were compared with pre-anesthesia and six hours post-return to a room. Data were analyzed and presented using a one-way analysis of variance with Bonferroni correction for multiple comparisons or unpaired two-tailed t-tests for pairwise comparison. Results None of the women had postoperative entrapment neuropathy. Six patients had >1,000 g of blood loss. Compression significantly increased from pre-anesthesia (left 13.6 ± 2.4, 95% CI: 12.18 to 14.52; right 13.4 ± 2.4, 95% CI: 12.41 to 14.69) to post-surgery (left, 17.4 ± 2.6, 95% CI: 15.68 to 18.12; right, 16.9 ± 2.6, 95% CI: 16.20 to 18.70) (p < 0.01). Compression pressure at post-surgery differed significantly between group P (left, 15.3 ± 1.3; right, 14.7 ± 1.8; 95% CI: -4.98 to -0.32) and group N (left, 18.1 ± 2.9; right, 17.8 ± 2.4; 95% CI: -5.38 to -0.26) (p < 0.05). The results are expressed as mean ± standard deviation, with P-values <0.05 indicating statistical significance. Conclusions In this study, no neuropathy occurred; however, over-compression risk with elastic stockings, especially when exceeding recommended pressure levels, was highlighted. Balancing thromboembolism prevention and over-compression risks is crucial for patients undergoing CSs with spinal anesthesia.

Cardiovascular effects of oxytocin and carbetocin at cesarean section. A prospective double-blind randomized study using noninvasive pulse wave analysis

BACKGROUND

Oxytocin is routinely administered after delivery for prophylaxis and treatment of postpartum hemorrhage, but it is associated with considerable cardiovascular side-effects. Carbetocin, a synthetic oxytocin analogue, has a myometrial contraction effect of 60 min when given IV, compared with 16 min for oxytocin.

OBJECTIVE

To investigate whether there are differences in cardiovascular effects between oxytocin and carbetocin up to 1 h after treatment.

METHODS

Sixty-one healthy pregnant women undergoing elective cesarean section in spinal anesthesia were randomized to receive an IV bolus of either five units (8.3 µg) of oxytocin or 100 µg of carbetocin after delivery of the baby. Heart rate (HR), mean arterial blood pressure, ECG ST index, oxygen saturation (SaO₂), and photoplethysmographic digital pulse wave analysis variables were recorded before and at 1, 5, 20, and 60 min after drug administration. Vasopressor use, uterine tonus, total bleeding, and need for additional uterotonics were also assessed. Repeated measurement ANOVA was used for statistical analyses.

RESULTS

The drugs had equal vasodilatory and hypotensive effects. Oxytocin, but not carbetocin, caused a decrease in HR at 1 min and a sustained decrease in cardiac left ventricular ejection time. Aggregate vasopressor use was higher in the carbetocin group. Neither drug caused any change in ST index, SaO₂, or subjective cardiac symptoms. Uterine tonus, need for additional uterotonics, or total bleeding did not differ significantly between the groups.

CONCLUSION

Single doses of oxytocin and carbetocin had similar dilatory effects on vascular tonus, where the difference in aggregate vasopressor use can be attributed to a more persistent hypotensive effect of carbetocin. A transient negative chronotropic and sustained negative inotropic effect occurred after oxytocin. Neither drug showed any alarmingly adverse effects. Differences in drug effects may be attributed to differences in oxytocin and vasopressin receptor signaling pathways.

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.

Continuous transthoracic echocardiographic monitoring for changes in maternal cardiac hemodynamics during cesarean section under combined epidural-spinal anesthesia: a prospective, observational study

The change in maternal hemodynamics during cesarean section has not been well studied. Continuous transthoracic echocardiography can monitor cardiac function continuously. This study aimed to evaluate the effectiveness of maternal hemodynamic parameters monitoring during cesarean section using continuous transthoracic echocardiography. In this prospective, observational study, women with an uncomplicated singleton pregnancy scheduled for elective cesarean section at term under combined spinal-epidural anesthesia were enrolled. Maternal hemodynamic parameters were assessed by continuous transthoracic echocardiography at 11 pre-set time points. The image quality of continuous transthoracic echocardiography was evaluated before measurement was performed. Totally, one hundred parturients were recruited, and transthoracic echocardiography images with sufficient quality for further analysis were obtained in 72 women. Following anesthesia, maternal heart rate decreased by 11.18% and cardiac output decreased by 7.82%, but stroke volume remained stable. After delivery of the neonate and placenta, stroke volume and cardiac output increased by 21.09% and 22.33%, respectively. End-diastolic volume also increased significantly after delivery of the neonate, but end-systolic volume was unchanged. Following delivery of the neonate, fractional shortening increased till the end of the cesarean section while total peripheral resistance decreased significantly. In conclusion, continuous transthoracic echocardiographic monitoring revealed that there were significant changes in hemodynamic parameters during cesarean section after delivery of the newborn and placenta, which warranted further investigation.

Low Serum Oxytocin Concentrations Are Associated with Painful Menstruation

Oxytocin-dependent mechanisms are hypothesized to contribute to painful menses, but clinical trials of oxytocin antagonists for dysmenorrhea have had divergent outcomes. In contrast, broader studies have shown that increased systemic oxytocin concentrations are associated with increased pain tolerance and improved psychosocial function. We sought to confirm whether increased serum oxytocin concentrations are associated with menstrual pain and other psychosocial factors. Women with a history of primary dysmenorrhea (n = 19), secondary dysmenorrhea (n = 12), and healthy controls (n = 15) completed pain and psychosocial questionnaires, provided a medical history, and rated their pain during the first 48 h of menses. Serum samples were collected during menses to measure oxytocin concentrations. Oxytocin was significantly lower in participants with a history of primary (704 ± 33 pg/mL; p < 0.001) or secondary (711 ± 66 pg/mL; p < 0.01) dysmenorrhea compared to healthy controls (967 ± 53 pg/mL). Menstrual pain over the past 3 months (r = -0.58; p < 0.001) and during the study visit (r = -0.45; p = 0.002) was negatively correlated with oxytocin concentrations. Pain catastrophizing (r = -0.39), pain behavior (r = -0.32), and pain interference (r = -0.31) were also negatively correlated with oxytocin levels (p's < 0.05). Oxytocin was not significantly correlated with psychosocial factors. Contrary to our hypothesis, women with a history of primary or secondary dysmenorrhea had lower oxytocin concentrations during menses when compared to healthy controls. Lower circulating oxytocin concentrations were also associated with worse menstrual pain and pain-related behavior. When considering the existing literature, low circulating oxytocin may be a sign of dysfunctional endogenous pain modulation.

Effects of Vasoactive Medications and Maternal Positioning During Cesarean Delivery on Maternal Hemodynamics and Neonatal Acid-Base Status

Maternal hemodynamics, positioning, and anesthesia technique for cesarean delivery influence neonatal acid-base balance; direct effects from drugs that cross the placenta also have an influence. Spinal anesthesia limits fetal exposure to depressant drugs and avoids maternal airway instrumentation, but is associated with hypotension. Hypotension may be prevented/treated with vasopressors and intravenous fluids. Current evidence supports phenylephrine as the first-line vasopressor. Fifteen degrees of lateral tilt during cesarean delivery has been advocated to relieve vena caval obstruction, but routine use may be unnecessary in healthy nonobese women having elective cesarean delivery if maternal blood pressure is maintained near baseline.

Effects of oxytocin and anaesthesia on vascular tone in pregnant women: a randomised double-blind placebo-controlled study using non-invasive pulse wave analysis

BACKGROUND

Oxytocin is an uterotonic drug with profound cardiovascular effects, which in compromised patients could lead to serious events. The objective was to investigate whether oxytocin affects cardiac function and vascular tone in large and small arteries. We hypothesized that oxytocin decreases arterial vascular tone and elevates cardiac output.

METHODS

51 pregnant women were randomised to treatment with 8.3 μg (5 U) oxytocin or placebo injection during first trimester surgical evacuation of the gravid uterus under general anaesthesia. Oxytocin or placebo was administered once either early or late in the procedure, in a double-blind fashion. Digital photoplethysmography pulse wave analysis variables, heart rate, mean arterial blood pressure and electrocardiographic ST index were recorded before and after anaesthesia and after each injection. Non-parametric statistics were used with a two-sided P value < 0.05 considered significant.

RESULTS

Anaesthesia induced a significant fall in blood pressure, heart rate and vascular tone in small and peripheral arteries. Oxytocin had a vasodilatory effect on small and peripheral arteries and increased the left cardiac ventricular ejection time. The ST index decreased.

CONCLUSIONS

Pulse wave analysis indicated peripheral vasodilation and increased cardiac output after oxytocin, implying increased myocardial oxygen demand. These effects might have been enhanced by the vasodilating effects of anaesthesia. Previous studies have demonstrated myocardial ischaemia after oxytocin, as reflected by a decrease in ST index in the present study.

TRIAL REGISTRATION

Trial registration number ISRCTN17860978 , 2018/03/14, Retrospectively registered.