Clinical pharmacokinetic properties of magnesium sulphate in women with pre-eclampsia and eclampsia

Impaired diaphragmatic excursion following magnesium sulfate administration in patients with preeclampsia with severe features: a prospective observational study

Magnesium sulfate is recognized for its muscular relaxant properties on both smooth and skeletal muscles; nevertheless, there are no prior studies examining the impact of magnesium administration on diaphragmatic movement, namely diaphragmatic excursion. Therefore, we aimed to evaluate diaphragmatic excursion as assessed by ultrasound before and after magnesium sulfate administration. Patients with a diagnosis of preeclampsia with severe features were screened for eligibility. Forty-seven patients with preeclampsia with severe features were included and available for final analysis. There was a significant reduction in diaphragmatic excursion 20 minutes after magnesium sulfate administration. Additionally, this study provides new insight into the dose effect between serum magnesium level and diaphragmatic excursion characterized by a negative correlation between serum magnesium level and diaphragmatic excursion, demonstrating that increased serum magnesium level is associated with increased diaphragmatic weakness.

Ischemia with no obstructed coronary arteries and microvascular testing procedures: a review of utility, pharmacotherapy, and current challenges

Ischemia with no obstructive coronary arteries (INOCA) is an increasingly recognized condition in patients presenting with angina and positive stress tests but without significant coronary artery stenosis. This review addresses the pathophysiology, diagnostic approaches, and management strategies associated with INOCA, emphasizing epicardial coronary spasms and coronary microvascular dysfunction (CMD) as underlying mechanisms and myocardial bridging (MB) as a risk factor. Diagnostic modalities include both non-invasive techniques and invasive procedures, such as acetylcholine provocation testing, to differentiate vasospasm from microvascular causes. The paper discusses a potential interference between vasodilators used in trans-radial access and coronary spasm testing. Long-term management approaches for INOCA patients, including pharmacologic therapies and lifestyle interventions, are reviewed.

Clinical impact of hypermagnesemia in acute kidney injury patients undergoing continuous kidney replacement therapy: A propensity score analysis utilizing real-world data

PURPOSE

While hypomagnesemia is known to be a risk factor for acute kidney injury (AKI), the impact of hypermagnesemia on prognosis in AKI patients undergoing continuous kidney replacement therapy (CKRT) remains unclear. This study investigates the relationship between hypermagnesemia and clinical outcomes in this patient population.

METHODS

A retrospective analysis was conducted using data from a multicenter medical repository spanning from 2001 to 2019, involving patients who underwent CKRT. Patients were categorized into normomagnesemia (<2 mEq/L) and hypermagnesemia groups based (≥2 mEq/L) on their levels at CKRT initiation.

RESULTS

Among the 2625 patients, 1194 (45.5 %) had elevated serum magnesium levels. The hypermagnesemia group exhibited a similar rate of non-recovery of renal function at 90-days compared to the normomagnesemia group (63.1 % vs. 62.8 %, odds ratio [OR] = 1.01, 95 % confidence interval [CI] 0.90-1.14). Furthermore, the high magnesium group demonstrated higher one-year all-cause mortality (hazard ratio [HR] 1.14, 95 % CI 1.07-1.21) and an elevated risk of one-year arrhythmia (HR 4.77, 95 % CI 1.59-14.29). There was no difference of incidence of seizure between hypermagnesemia and normomagnesemia group.

CONCLUSIONS

Our study suggests that hypermagnesemia in AKI patients undergoing CKRT is not associated with improved renal recovery but is linked to worse clinical outcomes, including all-cause mortality and arrhythmia. Close monitoring of serum magnesium levels is recommended in this population for optimizing clinical outcomes.

Hypertensive Disorders of Pregnancy: Diagnosis, Management and Timing of Birth

Hypertensive disorders of pregnancy are significant contributors to maternal and perinatal morbidity and mortality. The definition, classification, and management of these disorders have evolved over time. Notably, the disease classification enables caretakers to manage the disease as well as safeguard maternal and fetal health. The approach and management for pregnancies with gestational and chronic hypertension or pre-eclampsia with or without severe features should be adequately elucidated to mitigate adverse perinatal outcomes. This review aimed to present the most recent definition and classification of hypertensive disorders of pregnancy to address their management, determine the optimal timing of birth, and establish short- and long-term follow-up protocols following parturition.

Preeclampsia and eclampsia: Enhanced detection and treatment for morbidity reduction

Preeclampsia is a life-threatening complication that develops in 2-8% of pregnancies. It is characterized by elevated blood pressure after 20 weeks of gestation and may progress to multiorgan dysfunction, leading to severe maternal and fetal morbidity and mortality. The only definitive treatment is delivery, and efforts are focused on early risk prediction, surveillance, and severity mitigation. Anesthesiologists, as part of the interdisciplinary team, should evaluate patients early in labor in order to optimize cardiovascular, pulmonary, and coagulation status. Neuraxial techniques are safe in the absence of coagulopathy and aid avoidance of general anesthesia, which is associated with high risk in these patients. This review aims to provide anaesthesiologists with a comprehensive update on the latest strategies and evidence-based practices for managing preeclampsia, with an emphasis on perioperative care.

Diagnosis and Treatment of Eclampsia

Hypertensive disorders of pregnancy affect approximately 5% to 10% of pregnant women. Eclampsia is a serious hypertensive disorder that is primarily characterized by the onset of grand mal seizure activity in the absence of other causative conditions. While eclampsia is diagnosed clinically, laboratory tests are recommended to assess for complications. Treatment strategies for eclampsia focus on controlling seizures and managing hypertension. Acute care during a seizure is critical because of the need for immediate medical interventions, including the management of the airway, breathing, and circulation, as well as ensuring the safety of the patient during convulsions. Magnesium sulfate is the preferred anticonvulsant drug. Care must be taken during administration to prevent magnesium toxicity. Antihypertensive drugs used in eclampsia include labetalol, hydralazine and nifedipine. The definitive treatment of eclampsia is delivery. Close monitoring of both mother and fetus is important to identify any indications for delivery. The timing and mode of delivery depend on obstetric indications, the severity of eclampsia, the gestational age of the fetus, and the overall clinical status of the patient. Neuraxial anesthesia is the anesthesia of choice for conscious, seizure-free, and with stable vital signs women undergoing cesarean section.

Population pharmacokinetics and dose optimization of magnesium sulfate in Chinese preeclampsia population

OBJECTIVE

To establish the population pharmacokinetics (PPK) of magnesium sulfate (MgSO4)in women with preeclampsia (PE), and to determine the key covariates having an effect in magnesium pharmacokinetics in Chinese PE.

METHODS

Pregnant women with PE prescribed MgSO4 were enrolled in this prospective study from April 2021 to April 2023. On the initial day of administration, the patients were administered a loading dose of 5 g in conjunction with 10 g of magnesium sulfate as a maintenance dose. On the second day, only the maintenance dose was administration, and maternal blood samples were taken at 0, 4, 5, and 12 h after the second day's 10 g maintenance dose. The software Phoenix was used to estimate PPK parameters of MgSO4, such as clearance (CL) and volume of distribution (V), and to model PPK models with patient demographic, clinical, and laboratory covariates.

RESULTS

A total of 199 blood samples were collected from 51 women with PE and PPK profiles were analyzed. The PPK of MgSO4 is consistent with to a one-compartment model. The base model adequately described the maternal serum magnesium concentrations after magnesium administration. The population parameter estimates were as follows: CL was 2.98 L/h, V was 25.07 L. The model predictions changed significantly with covariates (BMI, creatinine clearance, and furosemide). Furosemide statistically influences V. The creatinine clearance, BMI and furosemide jointly affects CL. Monte Carlo simulation results showed that a loading dose combined with a maintenance dose would need to be administered daily to achieve the therapeutic blood magnesium concentrations. For the non-furosemide group, the optimal dosing regimen was a 5 g loading dose combined with a 10 g maintenance dose of MgSO4. For the furosemide group, the optimal dosing regimen was a 2.5 g loading dose combined with a 10 g maintenance dose of MgSO4.

CONCLUSIONS

The magnesium PPK model was successfully developed and evaluated in Chinese preeclampsia population, and the dose optimization of MgSO4 was completed through Monte Carlo simulation.

Challenges and Pitfalls of Research Designs Involving Magnesium-Based Biomaterials: An Overview

Magnesium-based biomaterials hold remarkable promise for various clinical applications, offering advantages such as reduced stress-shielding and enhanced bone strengthening and vascular remodeling compared to traditional materials. However, ensuring the quality of preclinical research is crucial for the development of these implants. To achieve implant success, an understanding of the cellular responses post-implantation, proper model selection, and good study design are crucial. There are several challenges to reaching a safe and effective translation of laboratory findings into clinical practice. The utilization of Mg-based biomedical devices eliminates the need for biomaterial removal surgery post-healing and mitigates adverse effects associated with permanent biomaterial implantation. However, the high corrosion rate of Mg-based implants poses challenges such as unexpected degradation, structural failure, hydrogen evolution, alkalization, and cytotoxicity. The biocompatibility and degradability of materials based on magnesium have been studied by many researchers in vitro; however, evaluations addressing the impact of the material in vivo still need to be improved. Several animal models, including rats, rabbits, dogs, and pigs, have been explored to assess the potential of magnesium-based materials. Moreover, strategies such as alloying and coating have been identified to enhance the degradation rate of magnesium-based materials in vivo to transform these challenges into opportunities. This review aims to explore the utilization of Mg implants across various biomedical applications within cellular (in vitro) and animal (in vivo) models.

Effects of magnesium sulfate combined with labetalol on inflammatory stress and pregnancy outcome of patients with gestational hypertension

Gestational hypertension (GH) is a common disorder during pregnancy that can cause adverse pregnancy outcomes. In the present study, magnesium sulfate (MgSO4) combined with labetalol was used for clinical treatment. Randomized controlled trial was conducted in 100 patients with GH, documented in the Department of Obstetrics and Gynecology (Taicang TCM Hospital) grouped into the experimental (Expt) and control (Ctrl) groups (n=50 cases/group). The Ctrl group was treated with MgSO4, whereas the Expt group was treated with MgSO4 + labetalol. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) in the Expt group were not significantly different from those in the Ctrl group (P>0.05). By contrast, the SBP and DBP were significantly lower after treatment than those before treatment in both groups (P<0.05). Whole blood viscosity, plasma viscosity and hematocrit were significantly lower in the Expt group compared with those in the Ctrl group after treatment (P<0.05). High mobility group box-1 protein, homocysteine and serum cystatin C levels in the Expt group were also markedly lower than those in the Ctrl group after treatment (P<0.05). In the Expt group, the rate of spontaneous vaginal delivery was much higher, whereas the rates of cesarean section and postpartum hemorrhage were markedly lower than those in the Ctrl group (P<0.05). The occurrence of fetal intrauterine distress, placental abruption, neonatal asphyxia, premature birth and neonatal death were also significantly lower in the Expt group than those in the Ctrl group (P<0.05). In conclusion, MgSO4 + labetalol could improve inflammatory stress and the hemodynamics of patients with GH, and may have a marked antihypertensive effect. Thus, it may improve pregnancy outcome and reduce perinatal complications.

Magnesium sulfate in preeclampsia: Broad indications, not only in neurological symptoms

The role of magnesium sulfate for treatment of eclampsia is well established. The medication proved to be superior to other anticonvulsants to reduce the incidence of recurrent convulsions among women with eclampsia. Additionally, magnesium sulfate has been indicated for women with preeclampsia with different severe features. However, despite these recommendations, many clinicians are still not confident with the use of magnesium sulfate, even in settings with high incidence of preeclampsia and unacceptable rates of maternal mortality. This review brings basic science and clinical information to endorse recommendations to encourage clinicians to use magnesium sulfate for patients with all severe features of preeclampsia, not only for women with neurological symptoms. Additionally, other benefits of magnesium sulfate in anesthesia and fetal neuroprotection are also presented. Finally, a comprehensive algorithm presents recommendations to manage patients with preeclampsia with severe features between 34 and 36+6 weeks.

Uterotonics, magnesium sulphate and antibiotics during childbirth and peripartum: Important obstetric drugs for the anaesthesiologist

The main causes of maternal mortality are comorbidities, hypertensive pregnancy syndrome, obstetric haemorrhage, and maternal sepsis. For this reason, uterotonics, magnesium sulphate, and antibiotics are essential tools in the management of obstetric patients during labour and in the peripartum period. These drugs are widely used by anaesthesiologists in all departments, and play a crucial role in treatment and patient safety. For the purpose of this narrative review, we performed a detailed search of medical databases and selected studies describing the use of these drugs in patients during pregnancy, delivery and the pospartum period. Uterotonics, above all oxytocin, play an important role in the prevention and treatment of pospartum haemorrhage, and various studies have shown that in obstetric procedures, such as scheduled and emergency caesarean section, they are effective at lower doses than those hitherto accepted. We also discuss the use of carbetocin as an effective alternative that has a therapeutic advantage in certain clinical circumstances. Magnesium sulphate is the gold standard in the prevention and treatment of eclampsia, and also plays a neuroprotective role in preterm infants. We describe the precautions to be taken during magnesium administration. Finally, we discuss the importance of understanding microbiology and the pharmacology of antibiotics in the management of obstetric infection and endometritis, and draw attention to the latest trends in antibiotic regimens in labour and caesarean section.

High-dose IV magnesium in mesothelioma patients receiving surgery with hyperthermic intraoperative cisplatin: Pilot studies and design of a phase II randomized clinical trial

INTRODUCTION

Hyperthermic intraoperative cisplatin (HIOC) is associated with acute kidney injury (AKI). Administration of high-dose magnesium attenuates cisplatin-induced AKI (CP-AKI) in animal models but has not been rigorously examined in humans.

METHODS

We tested the feasibility and safety of different doses of magnesium in mesothelioma patients receiving HIOC. In Pilot Study 1, we administered a 36-h continuous infusion of magnesium at 0.5 g/h, targeting serum magnesium levels between 3 and 4.8 mg/dL. In Pilot Study 2A, we administered a 6 g bolus followed by an infusion starting at 2 g/h, titrated to achieve levels between 4 and 6 mg/dL. We eliminated the bolus in Pilot Study 2B.

RESULTS

In Pilot Study 1, all five patients enrolled completed the study; however, median postoperative Mg levels were only 2.4 mg/dL. In Pilot Study 2A, two of four patients (50%) were withdrawn due to bradycardia during the bolus. In Pilot Study 2B, two patients completed the study whereas two developed postoperative bradycardia attributed to the magnesium.

CONCLUSIONS

A 0.5 g/h infusion for 36 h did not achieve therapeutic magnesium levels, while an infusion at 2 g/h was associated with bradycardia. These studies informed the design of a randomized clinical trial testing whether intravenously Mg attenuates HIOC-associated AKI.

Effect of maternal serum magnesium and calcium levels on umbilical glial fibrillary acidic protein levels in preterm labor

Magnesium can prevent astrocyte cell death and Glial Fibrillary Acidic Protein (GFAP) secretion as inflammatory marker in preterm delivery. This study was performed to analyze differences in umbilical cord GFAP levels in preterm labor given magnesium sulfate (MgSO4) as treatment group and control group and analyze the correlation between magnesium and calcium levels with umbilical GFAP levels. This quasi-experimental study was performed on 68 patients at Dr. Hasan Sadikin General Hospital from February-June 2021 consisting of 34 patients in each group. Maternal-umbilical cord magnesium levels, calcium levels, and GFAP levels were examined using ELISA test. The result was statistically measured by IBM SPSS 24.0. We found that there was a significant difference between maternal and umbilical magnesium levels and GFAP umbilical cord blood levels between the treatment and the control group (P < 0.05) in which GFAP level was higher in the control group. The multivariate analysis showed no significant relevance between mother magnesium and calcium level to umbilical cord GFAP level in the MgSO4 group. As conclusions, umbilical cord blood GFAP levels in preterm labor given MgSO4 were lower than in preterm deliveries who were not given MgSO4. There was no correlation between magnesium, calcium, and GFAP levels in the treatment group.

Magnesium Sulfate Use in Pregnancy for Preeclampsia Prophylaxis and Fetal Neuroprotection: Regimens in High-Income and Low/Middle-Income Countries

Magnesium sulfate is one of the most commonly used medications in obstetrics, most notably for the prevention of eclamptic seizures and fetal neuroprotection of the extremely preterm neonate. Pharmacokinetic and pharmacodynamic studies have demonstrated a variety of IV and IM regimens are effective for these indications. Existing models and data can be used to tailor treatment regimens to increase coverage in poor resource areas, maximize efficacy and minimize toxicity for patients of different weights and renal function.

Oral application of magnesium-L-threonate enhances analgesia and reduces the dosage of opioids needed in advanced cancer patients-A randomized, double-blind, placebo-controlled trial

PURPOSE

To investigate the effects of oral administration of magnesium-L-threonate, a novel magnesium compound, on the analgesic effect of opioids in patients with advanced cancer.

METHODS

We performed a prospective, randomized, double-blind trial at a tertiary hospital in Shanghai, China. Eligible cancer patients who took opioids orally were assigned randomly to receive L-TAMS capsules (1.5 g or 2.0 g according to weight) or a placebo (starch capsules). The primary outcome was the increase in the daily oral dose of morphine in each of the two groups, measured at 7, 14, 21, 30, 60, and 90 days during this trial.

RESULTS

A total of 116 patients from the oncology and pain departments, including inpatients and outpatients, were screened; 83 were enrolled. The increases in daily morphine doses began to differ from day 30 (L-TAMS group 9.85 mg/d vs. Placebo group 20.49 mg/d, p < 0.05); the differences persisted on day 60 (L-TAMS group 15.96 mg/d vs. Placebo group 29.06 mg/d, p < 0.05) and on day 90 (L-TAMS group 21.20 mg/d vs. Placebo group 40.44 mg/d, p < 0.01).

CONCLUSIONS

L-TAMS outperforms a placebo in enhancing the analgesic effect of opioids and reducing the necessary opioid dosage. Moreover, L-TAMS can significantly relieve opioid-induced constipation. These advantages may be beneficial to patients with advanced cancer.

A randomized controlled trial of loading dose alone versus pritchard regimen of magnesium sulphate, for seizure prophylaxis in severe preeclampsia

Background

Preeclampsia poses a significant risk of maternal and neonatal morbidity and mortality. Magnesium sulfate superiority for seizure prophylaxis in severe preeclampsia has been proven globally. However, the search for the lowest effective dose is an area of continuing research.

Aim

The aim of this study was to compare the effectiveness of loading dose with the Pritchard regimen of magnesium sulfate for seizure prophylaxis in severe preeclampsia.

Materials and Methods

A total of 138 eligible women after 28-week gestation with severe preeclampsia were randomized to either receiving a single loading dose of MgSO₄ (study arm: n = 69) or Pritchard regimen of MgSO₄ (control: n = 69). The effectiveness was assessed by the development of seizure. The results obtained were analyzed using SPSS version 21. Categorical variables were analyzed using the Chi-square test and normally distributed continuous variables were analyzed with t-test and Fisher's exact test. P < 0.05 was considered statistical significance.

Results

There were no significant differences between those who received only the loading dose when compared with those who had Pritchard regimen other than a single recorded convulsion among the control group (P = 0.316). Similarly, except for the duration of hospital stay which was significantly longer in the Pritchard group (P = 0.019), both the arms of the study shared similar maternal and fetal outcomes.

Conclusion

This study suggests the effectiveness of just the loading dose of magnesium sulfate when compared with the standardized Pritchard regimen in the prevention of seizure among women with severe preeclampsia. The study also demonstrated safety and similarity in fetal-maternal outcome. The loading dose only had an added advantage of shorter duration of hospital stay.

Strategy for Calculating Magnesium Sulfate Dose in Obese Patients: A Randomized Blinded Trial

Background. Magnesium sulfate has analgesic properties during the postoperative period. However, there is a knowledge gap in pharmacology related to the use of the real, ideal, or corrected ideal body weight to calculate its dose in obese patients. This trial compared postoperative analgesia using actual and corrected ideal body weight. Methods. Seventy-five obese patients scheduled to undergo laparoscopic gastroplasty or cholecystectomy under general anesthesia were randomly assigned to three groups. The patients in the control group did not receive magnesium sulfate; the other two groups received magnesium sulfate at 40 mg·kg−1 of actual body weight or corrected ideal body weight. Results. In patients with body mass index >30 mg·kg−2 (mean body mass index ranging from 32.964 kg·m−2 to 33.985 kg·m−2, according to the groups) scheduled for video laparoscopic cholecystectomy, there were no differences in the blood magnesium concentrations in the groups receiving magnesium sulfate throughout the study, regardless of whether the strategy to calculate its dose was based on total or corrected ideal body weight. Patients in the groups receiving magnesium sulfate showed a significant reduction in morphine consumption ( $p\le 0.001$ ) and pain scores ( $p=0.006$ ) in the postoperative period compared to those in the control group. There were no significant differences in morphine consumption ( $p=0.323$ ) or pain scores ( $p=0.082$ ) between the two groups receiving magnesium sulfate. There were no differences in the total duration of neuromuscular block induced by cisatracurium among the three groups ( $p=0.181$ ). Conclusions. Magnesium sulfate decreased postoperative pain and morphine consumption without affecting the recovery time of cisatracurium in obese patients undergoing laparoscopic cholecystectomy. Strategies to calculate the dose based on the actual or corrected ideal body weight had similar outcomes related to analgesia and the resulting blood magnesium concentration. However, as the sample in this trial presented body mass indices ranging from 30.11 kg·m−2 to 47.11 kg/m−2, further studies are needed to confirm these findings in more obese patients, easily found in centers specialized.

Maternal magnesium sulfate administration increases early-onset hyperkalemia risk in premature infants: A propensity score-matched, case-control study

BACKGROUND

Magnesium sulfate (MgSO₄) is a common substance administered to pregnant women with preeclampsia or eclampsia to prevent and treat seizures or gestational hypertension. This study aimed to evaluate whether administering maternal magnesium sulfate increased the risk of early-onset hyperkalemia in preterm infants.

METHODS

This single-center, propensity score-matched, case-control study examined preterm infants born within 24-36 weeks of gestation using electronic medical records between January 2015 and June 2019, in the Saitama City Hospital, Japan. We categorized infants according to their maternal MgSO₄ administration status. After adjusting for perinatal information and maternal treatment, we compared the incidence of the variables, including neonatal hyperkalemia, within 24 h after birth between the matched cohorts. All infants in Model 1 were analyzed separately, while in Model 2 infants with birth weight of less than 1000 g were excluded.

RESULTS

We enrolled 421 infants (maternal MgSO4 group, 124; control group, 297). Ninety-five infants in Model 1 and 86 in Model 2 were matched in each group using propensity scores, respectively. In the matched cohorts of both models, infants in the maternal MgSO₄ group had a higher hyperkalemia incidence than did those in the control group (42.1% vs. 7.4% in Model 1, 44.2% vs. 5.8% in Model 2, respectively; p < 0.0001). However, there was no relationship between the duration of intrauterine exposure to MgSO₄ and early-onset neonatal hyperkalemia incidence.

CONCLUSION

Our study demonstrated that maternal MgSO₄ administration, even for a short period of time, may increase the risk of early-onset hyperkalemia in preterm infants. Accordingly, physicians should be cautious when administering serum potassium to infants born to mothers administered MgSO₄, especially within 24 h after birth.

Directive clinique no 426 : Troubles hypertensifs de la grossesse : Diagnostic, prédiction, prévention et prise en charge

OBJECTIF

La présente directive a été élaborée par des fournisseurs de soins de maternité en obstétrique et en médecine interne. Elle aborde le diagnostic, l'évaluation et la prise en charge des troubles hypertensifs de la grossesse, la prédiction et la prévention de la prééclampsie ainsi que les soins post-partum des femmes avec antécédent de trouble hypertensif de la grossesse.

POPULATION CIBLE

Femmes enceintes. BéNéFICES, RISQUES ET COûTS: La mise en œuvre des recommandations de la présente directive devrait réduire l'incidence des troubles hypertensifs de la grossesse, en particulier la prééclampsie, et des issues défavorables associées. DONNéES PROBANTES: La revue exhaustive de la littérature a été mise à jour en tenant compte des nouvelles données probantes jusqu'en décembre 2020 et en suivant la même méthodologie que pour la précédente directive de la Société des obstétriciens et gynécologues du Canada (SOGC) sur les troubles hypertensifs de la grossesse. La recherche s'est limitée aux articles publiés en anglais ou en français. Les recommandations relatives aux traitements s'appuient d'abord sur les essais cliniques randomisés et les revues systématiques (lorsque disponibles), ainsi que sur l'évaluation des résultats cliniques substantiels chez les mères et les bébés. MéTHODES DE VALIDATION: Les auteurs se sont entendus sur le contenu et les recommandations par consensus et ont répondu à l'examen par les pairs du comité de médecine fœto-maternelle de la SOGC. Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique d'évaluation, de développement et d'évaluation (GRADE) et se sont gardé l'option de désigner certaines recommandations par la mention « bonne pratique ». Voir l'annexe A en ligne (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et conditionnelles [faibles]). Le conseil d'administration de la SOGC a approuvé la version définitive aux fins de publication.

PROFESSIONNELS CIBLES

Tous les fournisseurs de soins de santé (obstétriciens, médecins de famille, sages-femmes, infirmières et anesthésistes) qui prodiguent des soins aux femmes avant, pendant ou après la grossesse.

RECOMMANDATIONS

Guideline No. 426: Hypertensive Disorders of Pregnancy: Diagnosis, Prediction, Prevention, and Management

OBJECTIVE

This guideline was developed by maternity care providers from obstetrics and internal medicine. It reviews the diagnosis, evaluation, and management of the hypertensive disorders of pregnancy (HDPs), the prediction and prevention of preeclampsia, and the postpartum care of women with a previous HDP.

TARGET POPULATION

Pregnant women.

BENEFITS, HARMS, AND COSTS

Implementation of the recommendations in these guidelines may reduce the incidence of the HDPs, particularly preeclampsia, and associated adverse outcomes.

EVIDENCE

A comprehensive literature review was updated to December 2020, following the same methods as for previous Society of Obstetricians and Gynaecologists of Canada (SOGC) HDP guidelines, and references were restricted to English or French. To support recommendations for therapies, we prioritized randomized controlled trials and systematic reviews (if available), and evaluated substantive clinical outcomes for mothers and babies.

VALIDATION METHODS

The authors agreed on the content and recommendations through consensus and responded to peer review by the SOGC Maternal Fetal Medicine Committee. The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, along with the option of designating a recommendation as a "good practice point." See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).The Board of the SOGC approved the final draft for publication.

INTENDED USERS

All health care providers (obstetricians, family doctors, midwives, nurses, and anesthesiologists) who provide care to women before, during, or after pregnancy.

RECOMMENDATIONS

Hypertensive Disorders of Pregnancy: Common Clinical Conundrums

Importance

Hypertensive complications of pregnancy comprise 16% of maternal deaths in developed countries and 7.4% of deaths in the United States. Rates of preeclampsia increased 25% from 1987 to 2004, and rates of severe preeclampsia have increased 6.7-fold between 1980 and 2003.

Objective

The aim of this study was to review current and available evidence for common clinical questions regarding the management of hypertensive disorders of pregnancy.

Evidence Acquisition

Original research articles, review articles, and guidelines on hypertension in pregnancy were reviewed.

Results

Severe gestational hypertension should be managed as preeclampsia with severe features. Serum uric acid levels can be useful in predicting development of superimposed preeclampsia for women with chronic hypertension. When presenting with preeclampsia with severe features before 34 weeks, expectant management should be considered only when both maternal and fetal conditions are stable. In the setting of hypertensive disorders of pregnancy, oral antihypertensive medications should be initiated when systolic blood pressure is greater than 160 mm Hg or when diastolic blood pressure is greater than 110 mm Hg, with the most ideal agents being labetalol or nifedipine. Furthermore, although risk of preeclampsia recurrence in future pregnancy is low, women with a history of preeclampsia should be managed with 81 mg aspirin daily for preeclampsia prevention.

Conclusions and Relevance

Despite the frequency with which hypertensive disorders of pregnancy are encountered clinically, situations arise frequently with limited evidence to guide providers in their management. An urgent need exists to better understand this disease to optimize outcomes for impacted patients.

A novel 12-hour versus 24-hour magnesium sulfate regimen in the management of eclampsia and preeclampsia in Ghana (MOPEP Study): A randomized controlled trial

OBJECTIVE

We compared the efficacy of a 12-h versus 24-h regimen of intramuscular magnesium sulfate in the management of eclampsia and preeclampsia.

METHODS

This is an open-labeled parallel randomized controlled trial conducted in Accra, Ghana from November 2018 to November 2020. Participants were adult pregnant women admitted to the Korle Bu Teaching Hospital (KBTH) with a diagnosis of antepartum, intrapartum, or postpartum eclampsia or preeclampsia with severe features, having received no more than a loading dose of magnesium sulfate prior to admission at KBTH. Participants in the standard 24-h group received a loading dose of magnesium sulfate 4 g intravenous and 10 g intramuscular (5 g in each buttock) followed by six, 5 g intramuscular maintenance doses over 24 h. Participants in the 12-h intervention group received the same loading dose followed by three, 5 g intramuscular maintenance doses over 12 h. The primary outcome was occurrence of seizure after completion of the assigned magnesium sulfate regimen. Secondary outcomes were magnesium sulfate toxicity, magnesium sulfate side effects, maternal outcomes (mode of delivery, duration of inpatient admission, duration of urethral catheterization), maternal complications (pulmonary edema, acute kidney injury, intensive care unit admission, death), and neonatal outcomes.

RESULTS

Among 1176 total participants, we found no difference in occurrence of seizure after completion of the assigned regimen in the 24-h group (n = 5, 0.9%) versus the 12-h group (n = 2, 0.3%), P = 0.29; RR 0.40, 95% CI 0.08, 2.04), or in occurrence of seizure any time after enrollment (n = 9, 1.5% vs. n = 5, 0.9%, P = 0.28, RR 0.55, 95% CI 0.19-1.64). Participants in the 12-h group had a shorter duration of inpatient admission (9.4 ± 8.8 vs. 7.7 ± 6.5 days, P = 0.0009) and urethral catheterization (2.1 ± 1.0 vs. 1.9 ± 1.3 days, P < 0.0001). Rates of side effects from magnesium sulfate were lower in the 12-h group: pain at the injection site (94.8% (n = 548) vs. 91.5% (n = 540), P = 0.03), inflammation (62.2% (n = 358) vs. 40.0% (n = 237), P < 0.0001), and bleeding or bruising at the injection site (25.1% (n = 144) vs. 14.4% (n = 85), P < 0.0001).

CONCLUSIONS

Compared with 24 h, 12 h of intramuscular magnesium sulfate showed similar rates of seizures, with fewer side effects and shorter inpatient admission.

TRIAL REGISTRATION

Prospective registration was with Pan African Clinical Trial Registry (PACTR201811515303983): https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=4690.

A pilot study of the pharmacokinetics of continuous magnesium infusion in critically ill patients

Objective: The pharmacokinetics and haemodynamic effect of continuous magnesium infusion in non-cardiac intensive care unit (ICU) patients are poorly understood. We aimed to measure serum and urine magnesium levels during bolus and continuous infusion in critically ill adults, compare serum levels with those of a control population, and assess its haemodynamic effect. Design: Pharmacokinetic study Setting: A single tertiary adult ICU. Participants: Mechanically ventilated adults requiring vasopressor support. Intervention: A 10 mmol bolus of magnesium sulfate followed by 1.5-3 mmol/h infusion for 24 hours. Main outcome measures: The primary outcome was the change in total serum magnesium concentration. The main secondary outcome was mean arterial pressure (MAP)- adjusted vasopressor dose. Results: We matched 31 treated patients with 93 controls. Serum total magnesium concentration increased from a median 0.94 mmol/L (interquartile range [IQR], 0.83-1.10 mmol/L) to 1.38 mmol/L (IQR, 1.25-1.69 mmol/L; P < 0.001) and stabilised between a median 1.64 mmol/L (IQR, 1.38-1.88 mmol/L) at 7 hours and 1.77 mmol/L (IQR, 1.53-1.85 mmol/L) at 25 hours. This was significantly greater than in the control group (P < 0.001). The MAP-adjusted vasopressor dose decreased during magnesium infusion (P < 0.001). Conclusion: In critically ill patients, a magnesium sulfate bolus followed by continuous infusion achieved moderately elevated levels of total serum magnesium with a decrease in MAP-adjusted vasopressor dose. Trial registration number: ACTRN12619000925145.

A retrospective review of the risk factors affecting the therapeutic serum concentrations of magnesium sulfate in pre-eclamptic patients

WHAT IS KNOWN AND OBJECTIVE

To identify factors that may affect the therapeutic serum magnesium levels after intravenous administration for seizure prophylaxis in pre-eclamptic patients.

METHODS

One hundred and two women with PE with severe features were identified categorized into two groups: subtherapeutic and therapeutic group. Multivariate logistic regression analysis and receiver operation characteristic curve analysis were conducted for the risk factors influencing the serum magnesium concentration.

RESULTS

Among 102 eligible patients, 63 (62%) patients did not attain ideal therapeutic serum magnesium levels. Those patients had elevated albumin levels (p < 0.05), higher creatinine clearance (Ccr) (p < 0.001), and higher body mass index (BMI) (p < 0.001). Logistic regression analysis identified BMI and Ccr as independent risk factors for subtherapeutic serum magnesium concentration (p < 0.05). Receiver operating characteristic (ROC) curve analysis revealed a greater area under the curve for BMI than for Ccr in predicting subtherapeutic serum magnesium levels (0.787 vs. 0.774).

WHAT IS NEW AND CONCLUSION

Maternal body weight and renal function were independent risk factors for subtherapeutic serum magnesium concentration in the early stage after administration.

Eclampsia in the 21st century

The reported incidence of eclampsia is 1.6 to 10 per 10,000 deliveries in developed countries, whereas it is 50 to 151 per 10,000 deliveries in developing countries. In addition, low-resource countries have substantially higher rates of maternal and perinatal mortalities and morbidities. This disparity in incidence and pregnancy outcomes may be related to universal access to prenatal care, early detection of preeclampsia, timely delivery, and availability of healthcare resources in developed countries compared to developing countries. Because of its infrequency in developed countries, many obstetrical providers and maternity units have minimal to no experience in the acute management of eclampsia and its complications. Therefore, clear protocols for prevention of eclampsia in those with severe preeclampsia and acute treatment of eclamptic seizures at all levels of healthcare are required for better maternal and neonatal outcomes. Eclamptic seizure will occur in 2% of women with preeclampsia with severe features who are not receiving magnesium sulfate and in <0.6% in those receiving magnesium sulfate. The pathogenesis of an eclamptic seizure is not well understood; however, the blood-brain barrier disruption with the passage of fluid, ions, and plasma protein into the brain parenchyma remains the leading theory. New data suggest that blood-brain barrier permeability may increase by circulating factors found in preeclamptic women plasma, such as vascular endothelial growth factor and placental growth factor. The management of an eclamptic seizure will include supportive care to prevent serious maternal injury, magnesium sulfate for prevention of recurrent seizures, and promoting delivery. Although routine imagining following an eclamptic seizure is not recommended, the classic finding is referred to as the posterior reversible encephalopathy syndrome. Most patients with posterior reversible encephalopathy syndrome will show complete resolution of the imaging finding within 1 to 2 weeks, but routine imaging follow-up is unnecessary unless there are findings of intracranial hemorrhage, infraction, or ongoing neurologic deficit. Eclampsia is associated with increased risk of maternal mortality and morbidity, such as placental abruption, disseminated intravascular coagulation, pulmonary edema, aspiration pneumonia, cardiopulmonary arrest, and acute renal failure. Furthermore, a history of eclamptic seizures may be related to long-term cardiovascular risk and cognitive difficulties related to memory and concentration years after the index pregnancy. Finally, limited data suggest that placental growth factor levels in women with preeclampsia are superior to clinical markers in prediction of adverse pregnancy outcomes. This data may be extrapolated to the prediction of eclampsia in future studies. This summary of available evidence provides data and expert opinion on possible pathogenesis of eclampsia, imaging findings, differential diagnosis, and stepwise approach regarding the management of eclampsia before delivery and after delivery as well as current recommendations for the prevention of eclamptic seizures in women with preeclampsia.

Magnesium sulfate pharmacokinetics after intramuscular dosing in women with preeclampsia

BACKGROUND

Current intramuscular magnesium dosing regimens in low and middle-income countries are based on indirect absorption parameters to inform pharmacokinetic and pharmacodynamic response.

OBJECTIVE

To determine if therapeutic serum magnesium levels are obtained in women with severe preeclampsia receiving intramuscular administration of magnesium sulfate using the Pritchard regimen and to compare the key pharmacokinetic variables to those previously published.

STUDY DESIGN

Serum magnesium levels were obtained at multiple time points at baseline and after magnesium sulfate administration from women with severe preeclampsia receiving the standard Pritchard regimen for seizure prophylaxis at Bayero University, Kano, Nigeria. The pharmacokinetic profiles were constructed for the study cohort and the updated pharmacokinetic model was compared with the one that was previously published.

RESULTS

A total of 80 blood samples were collected from 20 women with severe preeclampsia (45 collected before childbirth and 35 collected after childbirth). After 11.5 hours of magnesium sulfate administration, 63% of women in the cohort had serum magnesium levels of ≥2.0 mmol/L. Data from women receiving the Pritchard regimen combined with data from women previously modeled after the receipt of intravenous magnesium sulfate were adequately described using a 2-compartment model with first-order absorption and linear elimination from the central compartment. All structural pharmacokinetic parameters including clearance, central volume of distribution, peripheral volume of distribution, and intercompartment clearance were adjusted for maternal weight, and the clearance was further adjusted for serum creatinine level and antepartum or postpartum status. The simulated pharmacokinetic profiles of the updated pharmacokinetic model and the previously published pharmacokinetic model are similar. In previously published pharmacokinetic modeling, absorption rate constant=0.32 and absolute bioavailability=0.86. In the updated pharmacokinetic model, absorption rate constant=0.45 and absolute bioavailability=0.91.

CONCLUSION

These data support the use of the Pritchard regimen as acceptable to achieve therapeutic serum magnesium levels and support the reported simulation of serum magnesium levels and eclampsia response associated with different intramuscular regimens.

The Role of Magnesium in Pregnancy and in Fetal Programming of Adult Diseases

Magnesium is an essential trace metal and a necessary factor for multiple biochemical functions in humans. Its role in biology is fundamental in over 600 enzymatic reactions implicated in protein synthesis, mitochondrial functions, neuromuscular activity, bone formation, and immune system competence. Magnesium status is relevant in fetal development during gestation and in the newborn growth during the perinatal period. Moreover, magnesium is able to influence fetal programming and disease presentation in childhood or adulthood. The aim of this review is to focus on this metal homeostasis, analyzing its normal values, the causes of hypomagnesemia, the interaction with drugs and other conditions, and the diseases associated with magnesium value alteration during pregnancy, in order to study its role in fetal programming of adult diseases. The data here reported clearly indicated the existence of a connection between magnesium status and human pathology starting from intrauterine life and extending into childhood and adulthood.

Efficacy of Magnesium Sulfate on Maternal Mortality in Eclampsia

Eclampsia is a common complication of preeclampsia patients and can be life-threatening for both the mother and the fetus. Hence, timely intervention and appropriate management of this detrimental condition are extremely crucial. Eclampsia is described as the occurrence of generalized convulsions in patients with preeclampsia. Magnesium sulfate (MgSO₄) is the drug of choice for treating and preventing eclampsia. This review aims to study and analyze the available literature on the pathogenesis of eclampsia, the pharmacology of MgSO₄, and its effectiveness in the management of eclampsia. Other proposed treatments and their comparative study with MgSO₄ are also discussed. Additionally, we examine the data regarding the impact of eclampsia, its public health burden, and the cost-effectiveness of MgSO₄. One of the major drawbacks associated with the use of MgSO₄ in low-income countries has been the cost of treatment and the lack of resources. We have analyzed the trials that have proposed alternate treatment regimens which could shape new guidelines to resolve these issues. For this review, we extensively studied abstract and full-text articles from multiple databases. This article discusses the pathophysiology of eclampsia, the pharmacology of MgSO₄, the issues surrounding eclampsia management, and how MgSO₄ benefits these patients.

Magnesium Sulfate Enables Patient Immobilization during Moderate Block and Ameliorates the Pain and Analgesic Requirements in Spine Surgery, Which Can Not Be Achieved with Opioid-Only Protocol: A Randomized Double-Blind Placebo-Controlled Study

Spine surgery is painful despite the balanced techniques including intraoperative and postoperative opioids use. We investigated the effect of intraoperative magnesium sulfate (MgSO₄) on acute pain intensity, analgesic consumption and intraoperative neurophysiological monitoring (IOM) during spine surgery. Seventy-two patients were randomly allocated to two groups: the Mg group or the control group. The pain intensity was significantly alleviated in the Mg group at 24 h (3.2 ± 1.7 vs. 4.4 ± 1.8, p = 0.009) and 48 h (3.0 ± 1.2 vs. 3.8 ± 1.6, p = 0.018) after surgery compared to the control group. Total opioid consumption was reduced by 30% in the Mg group during the same period (p = 0.024 and 0.038, respectively). Patients in the Mg group required less additional doses of rocuronium (0 vs. 6 doses, p = 0.025). Adequate IOM recordings were successfully obtained for all patients, and abnormal IOM results denoting warning criteria (amplitude decrement >50%) were similar. Total intravenous anesthesia with MgSO₄ combined with opioid-based conventional pain control enables intraoperative patient immobilization without the need for additional neuromuscular blocking drugs and reduces pain intensity and analgesic requirements for 48 h after spine surgery, which is not achieved with only opioid-based protocol.

[Prescription of phosphorus, calcium and magnesium: choice of the millimole unit to establish the equivalence of doses between oral and injectable forms]

OBJECTIVES

Information available on the packaging of drugs indicated for patients electrolytes replenishment differs from one manufacturer to another. They relate, for example, the unit chosen to express elemental electrolyte concentration. These differences constitute a risk factor for medication errors. This article proposes a clinical decision support tool which defines dose equivalences between the oral and injectable formulation galenic forms for medications providing phosphorus, calcium and magnesium and a calculated replenishment ratio.

METHODS

The amounts of elemental electrolyte were determined from the information contained on the packaging and the summaries of product characteristics. Only the specialties of our hospital drug formulary were studied. For each element, the replenishment ratio was determined from published data.

RESULTS

Equivalence tables were created for the phosphorus, calcium and magnesium between oral and injectable formulation. A clinical decision support tool was developed from these data.

CONCLUSION

The use of this tool is a first way to reduce the risk of medication errors. It remains to determine the conditions for its dissemination and evaluation. This issue raises the questions of the exclusive use of the millimole unit on packaging and for prescription, and that of the integration of this type of tool into prescription software and decision support systems.

Serum magnesium levels in normal pregnant women, severe preeclampsia, and severe preeclampsia with complications; a consideration for early supplementation?

OBJECTIVE

This study aims to compare serum magnesium levels of normal pregnant women, severe preeclampsia and severe preeclampsia with complications in the third trimester of pregnancy so that they can be used as a basis for earlier consideration of supplementation in pregnancy.

METHOD

This study was an observational study with a comparative cross-sectional design conducted in July-September 2019 in four hospitals in Makassar, namely Dr. Wahidin Soedirohusodo General Hospital, Hasanuddin University State University Hospital, Sitti Khadijah I Hospital and Children Hospital Siti Fatimah's Mother and Child Hospital. Respondents in this study were three-trimester pregnant women who were divided into three groups, 30 mothers with normal pregnancies, 30 mothers with severe preeclampsia, and 12 women with severe preeclampsia with complications. Criteria for respondents in this study were single pregnancy and not with systemic disease. Data collected included age, education, occupation, body mass index (BMI) before pregnancy, parity, the distance of pregnancy, history of preeclampsia, family planning history, history of antenatal care examination and pregnancy planning. Serum magnesium levels were determined using a Magnesium Assay Kit with a colorimetric method that was assessed for absorption by spectrophotometrics.

RESULTS

The mean serum magnesium levels were the lowest in the severe preeclampsia group (0.61mmol/L) compared to the severe preeclampsia group with complications (0.72mmol/L), and the normal pregnancy group (0.92mmol/L). Magnesium levels of the three groups differed significantly (p=0.008, p<0.05) CONCLUSION: Serum magnesium levels should be considered as a prognostic factor and supplementation intervention for pregnant women with preeclampsia.

Alternate Dosing Protocol for Magnesium Sulfate in Obese Women With Preeclampsia: A Randomized Controlled Trial

OBJECTIVE

To evaluate whether obese women need greater doses of magnesium sulfate to obtain therapeutic serum concentrations for eclamptic seizure prevention.

METHODS

Women with preeclampsia and a body mass index (BMI) of 35 or higher were randomly allocated to either the Zuspan regimen of magnesium sulfate (4-g intravenous [IV] loading dose, then a 1-g/h infusion) or to alternate dosing (6-g IV loading dose, then a 2-g/h infusion). Women had serum magnesium concentrations obtained at baseline, as well as after administration of magnesium sulfate at 1 hour, 4 hours, and delivery. The primary outcome was the proportion of women who had subtherapeutic serum magnesium concentrations (less than 4.8 mg/dL) 4 hours after administration. A sample size of 18 women per group was planned to compare the proportion of women with subtherapeutic serum magnesium concentrations in each group.

RESULTS

From July 12, 2016, to March 14, 2019, 89 women with preeclampsia were screened and 37 were enrolled: 18 to the Zuspan regimen and 19 to the alternate regimen. A significantly greater proportion of women administered the Zuspan regimen had subtherapeutic serum magnesium concentrations at 4 hours (100% [95% CI 59-100] vs 63% [95% CI 41-81]; P=.01) compared with women administered the alternate higher dose regimen. At 4 hours, mean concentrations were significantly higher in the alternate regimen group (3.53 mg/dL±0.3 [Zuspan regimen] vs 4.41±0.5 [alternate regimen]; P<.01).

CONCLUSION

The alternate dosing regimen of a 6-g IV loading dose followed by a 2-g/h IV maintenance dose more reliably achieves therapeutic serum magnesium concentrations (as defined by a concentration of at least 4.8 mg/dL) in obese women with preeclampsia.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02835339.

Population Pharmacokinetics of Magnesium Sulfate in Preeclampsia and Associated Factors

Background and Objective

The pharmacokinetic basis of magnesium sulphate (MgSO₄) dosing regimens for preeclampsia (PE) prophylaxis and treatment is not clearly established. The aim of study is to develop a population pharmacokinetic (PK) model of MgSO₄ in PE, and to determine key covariates having an effect in MgSO₄ pharmacokinetics in preeclampsia (PE) and to determine key covariates having an effect in MgSO₄ PK.

Methods

A prospective cohort study was conducted from June 2016 to February 2018 in patients with PE administered MgSO₄ as a 4-g bolus followed by continuous infusion at a rate of 1 g/h. Serum magnesium concentrations were obtained before treatment administration and 2, 6, 12, and 18 h after the initial dose. The software Monolix was used to estimate population PK parameters of MgSO₄ [clearance (CL), volume of distribution (V), half-life] and to develop a PK model with baseline patient demographic, clinical, and laboratory covariates.

Results

The study population consisted of 109 patients. The PK profile of MgSO₄ was adequately described by a one-compartment PK model. The model estimate of the population CL was 1.38 L/h; for V, it was 13.3 L; and the baseline magnesium concentration was 0.77 mmol/L (1.87 mg/dL). The baseline body weight and serum creatinine statistically influenced MgSO₄ CL and V, respectively. The model was parameterized as CL and V.

Conclusion

The PK of MgSO₄ in pregnant women with PE is significantly affected by creatinine and body weight. Pregnant women with PE and higher body weight have a higher V and, consequently, a lower elimination rate of MgSO₄. Pregnant women with PE and a higher serum creatinine value show lower CL and, therefore, lower MgSO₄ elimination rate.

The effects of maternal body mass index and plurality on maternal and umbilical cord serum magnesium levels in preterm birth at less than 32 weeks of gestation

OBJECTIVE

To evaluate the effects of maternal body mass index (BMI) and plurality on maternal and umbilical cord serum magnesium levels after antenatal magnesium sulfate treatment.

METHODS

This was a retrospective cohort analysis of 135 women treated with antenatal magnesium sulfate at less than 32 weeks of gestation between January 2012 and June 2018. Subjects were stratified into groups according to maternal BMI (group I [18.5-22.9 kg/m²], group II [23.0-24.9 kg/m²], and group III [≥25.0 kg/m²]) and plurality (singleton and twin). Univariable and multivariable analyses were performed to compare the umbilical cord serum magnesium levels between the groups.

RESULTS

Maternal serum magnesium levels were not significantly different between the maternal BMI groups and singleton and twin pregnancies. Umbilical cord serum magnesium levels were significantly different among the maternal BMI groups (3.3±1.2 mg/dL in group I, 3.3±1.2 mg/dL in group II, and 4.0±1.4 mg/dL in group III, P=0.003). The trend of increase in magnesium levels was statistically significant (P=0.001, Jonckheere-Terpstra test). Umbilical cord serum magnesium levels were not significantly different according to plurality. However, in the multivariable analysis, maternal BMI and plurality were not significantly associated with umbilical cord serum magnesium levels after adjusting for indication and total dose of magnesium sulfate treatment, gestational age at delivery, mode of delivery, neonatal sex, and birth weight.

CONCLUSION

Maternal BMI and plurality were not significantly associated with maternal or umbilical cord serum magnesium levels after exposure to antenatal magnesium sulfate treatment.

Multiple Gestations and Hypertensive Disorders of Pregnancy: What Do We Know?

PURPOSE OF REVIEW

The occurrence of hypertensive disorders of pregnancy (HDP) including gestational hypertension, chronic hypertension, preeclampsia, and eclampsia is proportional to the number of fetuses: singletons 6.5%, twins 12.7%, and triplets 20.0%. Literature on HDP in multifetal gestation is sparse compared with singletons. We aim to summarize the current evidence on HDP, specifically in twins.

RECENT FINDINGS

HDP occurs more frequently, at an earlier gestational age, and can present more severely and atypically in twin pregnancies. HDP in twins carries a higher risk of maternal/fetal morbidity and mortality including renal failure, stroke, cardiac arrest, pulmonary edema, placental abruption, cesarean delivery, fetal growth restriction, and iatrogenic preterm delivery. Low-dose aspirin (60-150 mg) should be initiated in all multifetal pregnancies to reduce the risk of preeclampsia. To improve outcomes and reduce inherent risks associated with multiple gestations, twins should be managed as high-risk pregnancies, and different from singletons.

Interrupted versus continuous magnesium sulfate and blood loss at cesarean delivery

OBJECTIVE

Magnesium sulfate is standard of care for prevention of eclampsia in women with preeclampsia with severe features. The American College of Obstetrics and Gynecology endorses its use throughout labor, delivery and the immediate postpartum period. Some providers pause magnesium sulfate infusion preoperatively due to concern for increased risk of uterine atony and postpartum hemorrhage. Using a non-inferiority analysis, we investigated the effect of interrupted versus continuous infusion of magnesium sulfate on postpartum hemorrhage in women with preeclampsia with severe features undergoing cesarean delivery.

STUDY DESIGN

Retrospective non-inferiority cohort study of women with preeclampsia with severe features treated with magnesium sulfate undergoing cesarean delivery with singleton pregnancies at tertiary care hospital from 2013 to 2018. The primary outcome was postpartum hemorrhage. Secondary outcomes included estimated blood loss, change in hematocrit and a composite of postpartum hemorrhage severity, including transfusion of blood products, use of more than one uterotonic and additional surgical interventions.

RESULTS

Of 249 women, magnesium sulfate infusion was interrupted in 171 (69%) and continued in 78 (31%). Women with interrupted magnesium sulfate infusion were more likely to be Caucasian (73% vs 67%, p = .024), have chronic hypertension (23% vs 1%, p < .001), labor prior to cesarean delivery (84% vs 55%, p < .001), undergo primary cesarean delivery (86% vs 67%, p = .005), and experience shorter surgical time (50 vs 55 min, p = .026). The rate of postpartum hemorrhage for those receiving interrupted magnesium sulfate infusion (9.9%) and continuous magnesium sulfate infusion (10.2%) was similar, falling within the non-inferiority margin (absolute difference 0.3%, 95% CI -7.8 to 8.4%, p = .88). There were no significant differences in the secondary outcomes.

CONCLUSION

Interrupted magnesium sulfate infusion is non-inferior to continued magnesium sulfate infusion for rates of postpartum hemorrhage in women with preeclampsia with severe features undergoing cesarean delivery.

Magnesium sulfate and risk of postpartum uterine atony and hemorrhage: A meta-analysis

OBJECTIVES

Magnesium sulfate (MgSO₄) is among the most commonly used medications in labor and delivery units. It has been used as a mean to protect against eclampsia and a neuroprotective agent for fetuses at risk of preterm birth. In the present study we investigated its impact in the occurrence of postpartum uterine atony and hemorrhage.

METHODS

We searched the Medline, Scopus, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL, Clinicaltrials.gov and Google Scholar databases for randomized trials and observational studies. Statistical analysis was performed with the Hartung-Knapp-Sidik-Jonkman model in RStudio using the meta package.

RESULTS

Twelve studies fitted the predetermined criteria and these involved 41,190 women of whom 10,565 (25.6 %) received MgSO_4. The meta-analysis revealed that the risk of postpartum uterine atony was similar among patients that received MgSO₄ and those that did not (OR 1.93, 95 % CI 0.78, 4.81). Estimated blood loss (SMD 0.04, 95 % CI -0.10, 0.18) as well as the risk of postpartum hemorrhage (OR 1.82, 95 % CI 0.99, 3.35) also did not differ. Subgroup analysis revealed that evidence drawn from observational studies indicates a significant effect of MgSO₄ on the odds of postpartum uterine atony and hemorrhage; however, randomized trials do not support this.

CONCLUSIONS

The results of our meta-analysis suggest that it is reasonable to consider MgSO4 in women at risk of delivering before the completion of its elimination half-life. However, physicians should be vigilant in cases at risk of postpartum hemorrhage as current data are very heterogeneous and should not be considered as definitive.

Microneedle-Assisted Percutaneous Transport of Magnesium Sulfate

OBJECTIVE

In vitro diffusion experiments were performed to assess the permeation of magnesium sulfate across pig skin.

METHODS

The mean thickness of the dermatomed porcine skin was 648 ± 12 µm. Magnesium concentration was measured using inductively coupled plasma-optical emission spectroscopy. Transdermal flux of magnesium sulfate across MN-treated and untreated porcine skin was obtained from the slope of the steady-state linear portion of cumulative amount versus time curve.

RESULTS

Statistical analysis of the results was done with Student's t-test. The transdermal flux of magnesium sulfate across microneedle-treated porcine skin was 134.19 ± 2.4 µg/cm2/h and transdermal flux across untreated porcine skin was 4.64 ± 0.05 µg/cm2/h. Confocal microscopy was used to visualize the microchannels created by a solid microneedle roller (500 µm).

CONCLUSION

From our confocal microscopy studies, it was evident that the 500 μm long microneedles disrupted the stratum corneum and created microchannels measuring 191 ± 37 µm. The increase in transdermal flux across the microneedle-treated skin was statistically significant compared to that of controls, i.e., without the application of microneedles. With the application of microneedles, the transdermal flux of magnesium permeated over 12 h was approximately 33-fold higher in comparison to passive diffusion across an intact stratum corneum.

Risk factors for sub-therapeutic serum concentrations of magnesium sulfate in severe preeclampsia of Chinese patients

Background

Magnesium sulfate (MgSO₄) is the standard drug for eclampsia prophylaxis and treatment. In China, the effective therapeutic serum magnesium level is 1.8–3.0 mmol/L. There is little information on how to achieve and maintain effective therapeutic concentrations. This study aimed to investigate risk factors for sub-therapeutic serum concentrations of MgSO₄ in patients with severe preeclampsia.

Methods

Patients with severe preeclampsia who received MgSO₄ intravenous infusion were retrospectively reviewed. The maternal demographic characteristics, regimens for the administration of MgSO₄, and lab test results of patients were collected. Multivariate logistic regression analysis and receiver operating characteristic (ROC) curve analysis were conducted for the risk factors influencing the serum magnesium concentration.

Results

A total of 93 patients with severe preeclampsia were included in the study. 52 (55.91%) patients did not attain therapeutic serum magnesium levels. A multivariate logistic regression analysis identified creatinine clearance (Ccr), whether the loading dose was given, and measurement time of serum magnesium concentration (referring to the time from start of MgSO4 infusion to blood draw for serum sampling) as independent risk factors for sub-therapeutic serum magnesium concentration (P < 0.05). ROC curve analysis indicated that the continuous variable Ccr had a significant predictive value for the serum magnesium concentration, which resulted in a cutoff point of 133 mL/min; while measurement time had limited predictive value, with cutoff point of 2.375 h.

Conclusions

Ccr, whether the loading dose was given, and measurement time were independent risk factors for sub-therapeutic serum magnesium concentration. A loading dose of MgSO₄ everytime before the maintenance dose, as well as the duration of MgSO4 maintenance dose of more than 2.375 h are recommended for all the patients with severe PE. Routine evaluation of serum magnesium levels is a recommended practice for women with severe PE and whose Ccr is ≥133 mL/min.

Magnesium, Oxidative Stress, Inflammation, and Cardiovascular Disease

Hypomagnesemia is commonly observed in heart failure, diabetes mellitus, hypertension, and cardiovascular diseases. Low serum magnesium (Mg) is a predictor for cardiovascular and all-cause mortality and treating Mg deficiency may help prevent cardiovascular disease. In this review, we discuss the possible mechanisms by which Mg deficiency plays detrimental roles in cardiovascular diseases and review the results of clinical trials of Mg supplementation for heart failure, arrhythmias and other cardiovascular diseases.

Electrophoretic measurement of water charge density and ion hydration

Water exchange between bulk water and water-ion complexes will be at equilibrium when the charge density of the complex surface equals the charge density of bulk water, producing a constant radius water-ion complex. This complex will migrate in an electric field at a velocity proportional to the complex radius. CE velocity is the sum of the complex charge-dependent velocity and the buffer electro-osmotic flow. Simultaneous use of both a base (1.07 mM imidazole) and an acid (1.5 mM MOPS) buffer negates EOF at pH 7.4. Electric fields below 300 V/cm (potassium, calcium) and 400 V/cm (magnesium) yield migration velocities with no dehydration of the water-ion complexes. The number of waters per complex increase with the ion charge density: K⁺ 1.90, Ca⁺⁺ 5.90, Mg⁺⁺ 6.59 waters/ion. The charge densities of the complexes are similar: K⁺ 1.24, Ca⁺⁺ 1.43, Mg⁺⁺ 1.21 e/nm² , for an average bulk water charge density of 1.29 ± 0.11 (SD) e/nm² . The addition of 0.1% Triton increases the number of waters for Mg⁺⁺ to 25.33 and lowers the charge density to 0.497 e/nm² . High electric field dehydration shows that calcium will be fully dehydrated at 638.3 V/cm and magnesium fully dehydrated at 925.5 V/cm, which occur at 6.15 and 5.78 nm from the membrane. Dehydrated magnesium will then bind to calcium channels leading to decreased smooth muscle activation.

Effects of different doses of magnesium sulfate on pneumoperitoneum-related hemodynamic changes in patients undergoing gastrointestinal laparoscopy: a randomized, double-blind, controlled trial

BACKGROUND

The infusion of magnesium sulfate is well known to reduce arterial pressure and attenuate hemodynamic response to pneumoperitoneum. This study aimed to investigate whether different doses of magnesium sulfate can effectively attenuate the pneumoperitoneum-related hemodynamic changes and the release of vasopressin in patients undergoing laparoscopic gastrointestinal surgery.

METHODS

Sixty-nine patients undergoing laparoscopic partial gastrectomy were randomized into three groups: group L received magnesium sulfate 30 mg/kg loading dose and 15 mg/kg/h continuous maintenance infusion for 1 h; group H received magnesium sulfate 50 mg/kg followed by 30 mg/kg/h for 1 h; and group S (control group) received same volume 0.9% saline infusion, immediately before the induction of pneumoperitoneum. Systemic vascular resistance (SVR), cardiac output (CO), mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), serum vasopressin and magnesium concentrations were measured. The extubation time, visual analogue scale were also assessed. The primary outcome is the difference in SVR between different groups. The secondary outcome is the differences of other indicators between groups, such as CO, MAP, HR, CVP, vasopressin and postoperative pain score.

RESULTS

Pneumoperitoneum instantly resulted in a significant reduction of cardiac output and an increase in mean arterial pressure, systemic vascular resistance, central venous pressure and heart rate in the control group (P <  0.01). The mean arterial pressure (T2 - T4)_, systemic vascular resistance (T2 - T3), central venous pressure(T3-T5) and the level of serum vasopressin were significantly lower (P <  0.05) and the cardiac output (T2 - T3) was significantly higher (P <  0.05) in group H than those in the control group. The mean arterial pressure (T4), systemic vascular resistance (T2), and central venous pressure(T3-T4) were significantly lower in group H than those in group L (P <  0.05). Furthermore, the visual analog scales at 5 min and 20 min, the level of vasopressin, and the dose of remifentanil were significantly decreased in group H compared to the control group and group L (P <  0.01).

CONCLUSION

Magnesium sulfate could safely and effectively attenuate the pneumoperitoneum-related hemodynamic instability during gastrointestinal laparoscopy and improve postoperative pain at serum magnesium concentrations above 2 mmol/L.

TRIAL REGISTRATION

The study was retrospectively registered at Chinese Clinical Trial Registry; the registration number is ChiCTR-IPD-17011145, principal investigator: D.Y. Q., date of registration: April 13, 2017.

Safety of prolonged magnesium sulfate infusions during treatment for severe pediatric status asthmaticus

OBJECTIVE

Magnesium sulfate (Mg) is one of several "second-tier" therapies for treating severe status asthmaticus. Pediatric reports primarily describe bolus use with limited data regarding prolonged infusions. We sought to describe the safety of prolonged Mg infusions during therapy of status asthmaticus in critically ill children.

DESIGN

Single center, retrospective study.

SETTING

Thirty-four-bed tertiary level medical/surgical/cardiac surgical pediatric intensive care unit.

PATIENTS

Pediatric patients 2 to 18 years of age admitted with status asthmaticus receiving Mg infusion for more than 24 hours.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN FINDINGS

A total of 154 children received Mg infusions for a median of 53.4 hours (interquartile range = 36.6-74.8). The most common adverse event (AE) was hypotension (48.1%), almost exclusively diastolic (94%), and was mostly limited to 1 blood pressure measurement (78%). 2.9% of events required intervention (fluids, decrease Mg infusion). Other AEs included nausea/emesis (22.7%), transient weakness (14.9%), and flushing (6.5%). Five patients experienced serious AEs including hypotonia (n = 1), escalation to continuous or bilevel positive airway pressure (n = 3), and sedation (n = 1), all attributed to progression of underlying medical disease. No patient required endotracheal intubation. Supratherapeutic levels (>6 mg/dL) were uncommon (2%) and were not more likely to be associated with AEs. Most (81%) patients were therapeutic by the 2nd Mg level check.

CONCLUSION

Prolonged Mg infusions were well tolerated in pediatric status asthmaticus patients. While diastolic hypotension was not uncommon, rarely were interventions deemed necessary. No serious AEs were attributed to Mg. Toxicity was uncommon suggesting that Mg levels could potentially be checked less frequently than historically reported.

Incidence of Adverse Drug Reactions in High-Risk Pregnancy: A Prospective Cohort Study in Obstetric Intensive Care

PURPOSE

To estimate the cumulative incidence of adverse drug reactions (ADRs) in women with high-risk pregnancy hospitalized in an obstetric intensive care unit, then to describe the medicines involved and to identify major risk factors.

METHODS

From June 2016 to December 2017, patients admitted to the ICU with high-risk pregnancy were considered eligible in this observational, longitudinal, prospective study. Patients were investigated daily for the occurrence of ADRs through pharmaceutical anamnesis, active search in medical records and questioning of the health team. Suspected ADRs were classified according to Naranjo's algorithm. Written informed consent was obtained from all patients. Univariate and multivariate logistic regression were used to identify risk factors of ADR.

RESULTS

The study population consisted of 607 high-risk pregnancies from 851 women admitted to the ICU, of whom 244 admitted for non-obstetric conditions, with an ICU stay less than 24 h or readmitted to the ICU were excluded. The mean age was 27.0 ± 7.5 years-old, mean gestational age was 33.8 ± 6.3 weeks. ADR were observed in 165 women (27.2%). No severe ADR was observed and 29.7% were of moderate severity. The most often implicated medicine was magnesium sulphate (25.2%) with 44.5% of patients administered that substance experiencing ADRs consisting of somnolence (68.6%), absent patellar reflex (21.6%) and hypotension (9.8%). Risk factors of ADR were blood pressure (adjusted odds-ratio (aOR) 1.02), haemoglobin level (aOR 1.21) and body temperature (aOR 0.71).

CONCLUSIONS

ADRs affect about one third of high-risk pregnancies, mainly due to magnesium sulphate administrations. High blood pressure, lower body temperature, and high haemoglobin concentration on admission were associated with an increased risk of ADR.