Maternal Hemodynamic Effects of Medical Gases and Uterotonics in Obstetrics

Aim of study: To elucidate the hemodynamic effects of pharmaceutical and medical interventions during pregnancy and childbirth on the mother.Introduction: Oxytocin, oxygen, and nitrous oxide are pharmaceuticals very commonly used in labor and delivery. These pharmaceuticals have known cardiovascular adverse effects. Some of these effects might be detrimental for the mother in case of major blood loss or preexisting cardiovascular disease, but the full extent of these effects is not known. The newer uterotonic carbetocin may have another adverse effect profile.Study population: Pregnant women during elective cesarean section; first trimester pregnant women during scheduled surgery for suction curettage; and pregnant and nonpregnant women during the third trimester.Methods: Cardiovascular effects are measured through ECG, blood pressure, oxygen saturation, and photoplethysmographic pulse wave analysis. By measuring the light absorption of infrared light through the finger, a waveform is obtained, from which it is possible to calculate indices of vascular stiffness and cardiac performance.Results: Oxytocin and carbetocin both have similar effects of vasodilation and blood pressure decrease. Pregnant women experienced more profound subjective side effects from nitrous oxide inhalations than nonpregnant controls. Oxygen alone and in a mix with nitrous oxide have vasoconstrictive and possible negative inotropic effects. These effects were more profound in pregnant women than in nonpregnant controls.Conclusion: The abovementioned medical interventions have cardiovascular effects that are sometimes quite profound. These effects can be shown with a simple and pain-free methodology. Carbetocin seems to have similar cardiovascular adverse effects compared to Oxytocin. Prudence should be taken when administering these drugs to compromised mothers. Both nitrous oxide and oxygen have vasoconstrictive and possible negative inotropic effects that were more prominent in pregnant women than in nonpregnant controls. Some of the effects seen from nitrous oxide might be due to the oxygen fraction in the gas mixture. Awareness of cardiovascular effects is important when treatment of the mother with oxytocin receptor agonists as well as with nitrous oxide and oxygen is considered. Oxygen treatment should not be used without a precise indication

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

Objective: To investigate changes in maternal ECG ST index, blood pressure (BP), cardiac left ventricular (LV) ejection function and vascular tone/stiffness in large and small arteries occurring during elective cesarean section (CS) in spinal anesthesia. Material and methods: Twenty-six women were monitored with photoplethysmographic digital pulse wave (PW) analysis (DPA) before and after spinal anesthesia, after delivery of the baby, after 5 IU oxytocin bolus IV, and 5 min later. Statistics with Wilcoxon matched-pairs signed-rank and Friedman tests at a

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

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

Management practices for postdural puncture headache in obstetrics: a prospective, international, cohort study

© 2020 British Journal of AnaesthesiaBackground: Accidental dural puncture is an uncommon complication of epidural analgesia and can cause postdural puncture headache (PDPH). We aimed to describe management practices and outcomes after PDPH treated by epidural blood patch (EBP) or no EBP. Methods: Following ethics committee approval, patients who developed PDPH after accidental dural puncture were recruited from participating countries and divided into two groups, those receiving EBP or no EBP. Data registered included patient and procedure characteristics, headache symptoms and intensity, management practices, and complications. Follow-up was at 3 months. Results: A total of 1001 patients from 24 countries were included, of which 647 (64.6%) received an EBP and 354 (35.4%) did not receive an EBP (no-EBP). Higher initial headache intensity was associated with greater use of EBP, odds ratio 1.29 (95% confidence interval 1.19–1.41) per pain intensity unit increase. Headache intensity declined sharply at 4 h after EBP and 127 (19.3%) patients received a second EBP. On average, no or mild headache (numeric rating score≤3) was observed 7 days after diagnosis. Intracranial bleeding was diagnosed in three patients (0.46%), and backache, headache, and analgesic use were more common at 3 months in the EBP group. Conclusions: Management practices vary between countries, but EBP was more often used in patients with greater initial headache intensity. EBP reduced headache intensity quickly, but about 20% of patients needed a second EBP. After 7 days, most patients had no or mild headache. Backache, headache, and analgesic use were more common at 3 months in patients receiving an EBP

Management practices for postdural puncture headache in obstetrics : a prospective, international, cohort study

Background: Accidental dural puncture is an uncommon complication of epidural analgesia and can cause postdural puncture headache (PDPH). We aimed to describe management practices and outcomes after PDPH treated by epidural blood patch (EBP) or no EBP. Methods: Following ethics committee approval, patients who developed PDPH after accidental dural puncture were recruited from participating countries and divided into two groups, those receiving EBP or no EBP. Data registered included patient and procedure characteristics, headache symptoms and intensity, management practices, and complications. Follow-up was at 3 months. Results: A total of 1001 patients from 24 countries were included, of which 647 (64.6%) received an EBP and 354 (35.4%) did not receive an EBP (no-EBP). Higher initial headache intensity was associated with greater use of EBP, odds ratio 1.29 (95% confidence interval 1.19-1.41) per pain intensity unit increase. Headache intensity declined sharply at 4 h after EBP and 127 (19.3%) patients received a second EBP. On average, no or mild headache (numeric rating score <= 3) was observed 7 days after diagnosis. Intracranial bleeding was diagnosed in three patients (0.46%), and backache, headache, and analgesic use were more common at 3 months in the EBP group. Conclusions: Management practices vary between countries, but EBP was more often used in patients with greater initial headache intensity. EBP reduced headache intensity quickly, but about 20% of patients needed a second EBP. After 7 days, most patients had no or mild headache. Backache, headache, and analgesic use were more common at 3 months in patients receiving an EBP