Life-threatening bronchospasm after intramuscular carboprost for postpartum haemorrhage

Preventing postpartum hemorrhage with combined therapy rather than oxytocin alone

Postpartum hemorrhage is the leading cause of maternal morbidity and mortality worldwide, with uterine atony estimated to account for 70% to 80% of cases, thereby remaining the single most common cause. Pharmacotherapy remains the first-line preventative therapy for postpartum hemorrhage. These therapies may be single (oxytocin, carbetocin, methylergonovine, ergometrine, misoprostol, prostaglandin analogs, or tranexamic acid) or combination therapies, acting in an additive, infra-additive, or synergistic fashion to prevent postpartum hemorrhage. Evidence is strong for the use of oxytocin, the first-line uterotonic agent in the United States for prevention of postpartum hemorrhage. Although carbetocin, a long-acting analog of oxytocin, is not yet available for use in the United States, it is likely the most effective single pharmacologic therapy for prevention of postpartum hemorrhage and need for additional uterotonics. Use of second-line uterotonics such as methylergonovine, misoprostol, and carboprost in combination with oxytocin has an additive or synergistic effect and a greater risk reduction for postpartum hemorrhage prevention compared with oxytocin alone. Therefore, combined therapy rather than oxytocin alone should be advised for preventing postpartum hemorrhage. Tranexamic acid has been found to be both effective and safe for decreasing maternal mortality in women with postpartum hemorrhage, and prophylactic use of tranexamic acid may decrease the need for packed red blood cell transfusions and/or uterotonics. The WOMAN-2 Trial, designed to assess if tranexamic acid prevents postpartum hemorrhage in women with moderate to severe anemia undergoing vaginal delivery, is currently recruiting participants. The additive, infra-additive, or synergistic action of oxytocin in combination with other second-line therapies deserves further study.

Postpartum Respiratory Depression

Postpartum respiratory depression is a complex, multifactorial issue that encompasses a patient's baseline preexisting conditions, certain pregnancy-specific conditions or complications, as well as the iatrogenic element of various medications given in the peripartum period. In this review, we discuss many of these factors including obesity, sleep-disordered breathing, chronic lung disease, neuromuscular disorders, opioids, preeclampsia, peripartum cardiomyopathy, postpartum hemorrhage, amniotic fluid embolism, sepsis, acute respiratory distress syndrome (ARDS), and medications such as analgesics, sedatives, anesthetics, and magnesium. Current recommendations for screening, treatment, and prevention are also discussed.

Prostaglandins for Postpartum Hemorrhage: Pharmacology, Application, and Current Opinion

BACKGROUND

Postpartum hemorrhage (PPH) remains a common cause of maternal mortality worldwide. Medical intervention plays an important role in the prevention and treatment of PPH. Prostaglandins (PGs) are currently recommended as second-line uterotonics, which are applied in cases of persistent bleeding despite oxytocin treatment.

SUMMARY

PG agents that are constantly used in clinical practice include carboprost, sulprostone, and misoprostol, representing the analogs of PGF2α, PGE2, and PGE1, respectively. Injectable PGs, when used to treat PPH, are effective in reducing blood loss but probably induce cardiovascular or respiratory side effects. Misoprostol is characterized by oral administration, low cost, stability in storage, broad availability, and minimal side effects. It remains a treatment option for uterine atony in low-resource settings, but its effectiveness as a uterotonic for independent application may be limited. Key Messages: The present review article discusses the physiological roles of various natural PGs, evaluates the existing evidence of PG analogs in the prevention and treatment of PPH, and finally provides a reference to assist obstetricians in selecting appropriate uterotonics.

Use of Antihypertensive Medications and Uterotonics During Delivery Hospitalizations in Women With Asthma

OBJECTIVE

To estimate whether the diagnosis of asthma is associated with the use of specific uterotonic and antihypertensive medications during delivery hospitalizations.

METHODS

We used Perspective, an administrative database, to determine whether women hospitalized for delivery complicated by postpartum hemorrhage or preeclampsia received uterotonics and antihypertensive medications differentially based on the absence or presence of asthma from 2006 to 2015. Given that carboprost and intravenous (IV) labetalol may be associated with asthma exacerbation, adjusted models for receipt of these medications were created with adjusted risk ratios with 95% CIs as measures of effect. Risk for status asthmaticus based on receipt of carboprost and IV labetalol was analyzed.

RESULTS

Over the study period, a total of 5,691,178 women were analyzed, of whom 239,915 (4.2%) had preeclampsia and 139,841 postpartum hemorrhage (2.5%). Carboprost was used less frequently in patients with asthma compared with patients with no asthma (11.4% vs 18.0%) in comparison with IV labetalol, which was used more commonly when a diagnosis of asthma was present (18.5% vs 16.7%). In unadjusted analysis, the presence of asthma was associated with a 37% decrease in likelihood of carboprost use and an 11% increase in likelihood of labetalol use. In adjusted analysis, the presence of asthma was associated with a 32% decrease in likelihood of carboprost use (adjusted risk ratio 0.68, 95% CI 0.62-0.74) compared with a 7% decrease in labetalol use (adjusted risk ratio 0.93, 95% CI 0.90-0.97). Risk for status asthmaticus was significantly increased with use of IV labetalol compared with other antihypertensive medications (6.5 vs 1.7/1,000 delivery hospitalizations, P<.01).

CONCLUSION

There may be an opportunity to reduce use of β-blockers and carboprost among patients with asthma. Given their association with status asthmaticus, these drugs should be used cautiously in women with asthma.

Uterotonic Medications: Oxytocin, Methylergonovine, Carboprost, Misoprostol

Uterine atony is a common cause of primary postpartum hemorrhage, which remains a major cause of pregnancy-related mortality for women worldwide. Oxytocin, methylergonovine, carboprost, and misoprostol are commonly used to restore uterine tone. Oxytocin is the first-line agent. Methylergonovine and carboprost are both highly effective second-line agents with severe potential side effects. Recent studies have called into question the effectiveness of misoprostol as an adjunct to other uterotonic agents, but it remains a useful therapeutic in resource-limited practice environments. We review the current role these medications play in the prevention and treatment of uterine atony.

Simultaneous determination of carboprost methylate and its active metabolite carboprost in dog plasma by liquid chromatography-tandem mass spectrometry with positive/negative ion-switching electrospray ionization and its application to a pharmacokinetic study

A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method using positive/negative electrospray ionization (ESI) switching for the simultaneous quantitation of carboprost methylate and carboprost in dog plasma has been developed and validated. After screening, the esterase inhibitor, dichlorvos was added to the whole blood at a ratio of 1:99 (v/v) to stabilize carboprost methylate during blood collection, sample storage and LLE. Indomethacin was added to plasma to inhibit prostaglandins synthesis after sampling. After liquid-liquid extraction of 500μL plasma with ethyl ether-dichloromethane (75:25, v/v), analytes and internal standard (IS), alprostadil-d4, were chromatographed on a CAPCELL PAK Phenyl column (150×2.0mm, 5μm) using acetonitrile-5mM ammonium acetate as mobile phase. Carboprost methylate was detected by positive ion electrospray ionization followed by multiple reaction monitoring (MRM) of the transition at m/z 400.5→329.3; the carboprost and IS were detected by negative ion electrospray ionization followed by MRM of the transitions at m/z 367.2→323.2, and 357.1→321.2, respectively. The method was linear for both analytes in the concentration range 0.05-30ng/mL with intra- and inter-day precisions (as relative standard deviation) of ≤6.75% and accuracy (as relative error) of ≤7.21% and limit of detection (LOD) values were 10 and 20pg/mL, respectively. The method was successfully applied to a pharmacokinetic study of the analytes in beagle dogs after intravaginal administration of a suppository containing 0.5mg carboprost methylate.

Sulprostone for postpartum hemorrhage in a parturient with a history of Tako-tsubo cardiomyopathy

A 32 year old parturient with a history of Tako-tsubo cardiomyopathy, who suffered from postpartum hemorrhage for which sulprostone was administered without any adverse events, is reported. Anesthetic considerations related to the management of patient with a history of Tako-tsubo cardiomyopathy, especially triggers that may cause a recurrence, are described. The potential deleterious effects of sulprostone in a patient with a history of Tako-tsubo cardiomyopathy are discussed.

Anaesthesia for emergency caesarean section in a patient with large anterior mediastinal tumour presenting as intrathoracic airway compression and superior vena cava obstruction

Anterior mediastinal mass is an uncommon pathology that presents significant anaesthetic challenges because of cardiopulmonary compromise. We present a case that presented in the third trimester of pregnancy with severe breathlessness, orthopnoea, and symptoms of superior vena cava obstruction. The patient had emergency Caesarean section under epidural anaesthesia with a good outcome. The paper discusses the relevant perioperative considerations for this complex scenario and reviews reports of similar conditions.

Maternal haemorrhage

Maternal haemorrhage is the leading cause of preventable maternal death worldwide and encompasses antepartum, intrapartum, and postpartum bleeding. This review highlights factors that predispose to severe bleeding, its management, and the most recent treatment and guidelines. Advances in obstetric care have provided physicians with the diagnostic tools to detect, anticipate, and prevent severe life-threatening maternal haemorrhage in most patients who have had prenatal care. In an optimal setting, patients at high risk for haemorrhage are referred to tertiary care centres where multidisciplinary teams are prepared to care for and deal with known potential complications. However, even with the best prenatal care, unexpected haemorrhage occurs. The first step in management is stabilization of haemodynamic status, which involves securing large bore i.v. access, invasive monitoring, and aggressive fluid management and transfusion therapy. Care for the patient with maternal bleeding should follow an algorithm that goes through a rapid and successive sequence of medical and surgical approaches to stem bleeding and decrease morbidity and mortality. With the addition of potent uterotonic agents and the advent of minimally invasive interventional radiological techniques such as angiographic embolization and arterial ligation, definitive yet conservative management is now possible in an attempt to avoid hysterectomy in patients with severe peripartum bleeding. If these interventions are inadequate to control the bleeding, the decision to proceed to hysterectomy must be made expeditiously. Recombinant factor VIIa is a relatively new treatment that could prove useful for severe coagulopathy and intractable bleeding.

Challenges of major obstetric haemorrhage

Every minute of every day, a woman dies in pregnancy or childbirth. The biggest killer is obstetric haemorrhage, the successful treatment of which is a challenge for both the developed and developing worlds. The presence of an attendant at every birth and access to emergency obstetric care are key to reducing maternal morbidity and mortality in the developing world while resource-rich countries have a rising caesarean section rate with its consequential effect on the incidence of abnormal placentation and its link with peripartum hysterectomy. Management of obstetric haemorrhage involves early recognition, assessment and resuscitation. Various methods are available to try to stop the bleeding - from pharmacological methods to aid uterine contraction (e.g., oxytocinon, ergometrine and prostaglandins) to surgical methods to stem the bleeding (e.g., balloon tamponade, compression sutures or arterial ligation). Interventional radiology can be used if placenta accreta is suspected. Cell salvage has been introduced into obstetrics relatively recently in an attempt to reduce allogeneic transfusion.

Strategies to manage major obstetric haemorrhage

PURPOSE OF REVIEW

Haemorrhage remains a cause of significant maternal morbidity and mortality. This review summarizes the prevention, management and treatment of obstetric haemorrhage and highlights recent advances and developments.

RECENT FINDINGS

Postpartum haemorrhage is the most common cause of major obstetric haemorrhage and is usually due to uterine atony. Pharmacological treatment has not altered much in recent years with oxytocin and ergometrine remaining first-line options. Although controversy surrounds its advantages over other uterotonics, the use of misoprostol has been increasing, especially in resource-poor countries. Placenta accreta is becoming more common, a sequelae to the rising caesarean section rate. Interventional radiology may reduce blood loss in these cases. Uterine compression sutures, intrauterine tamponade balloons and cell salvage have all made their debut in the last decade.

SUMMARY

Accurate diagnosis and appropriate management of obstetric haemorrhage can reduce maternal morbidity and mortality. This review outlines the current evidence.