Obstetric Anesthesia

Substance use disorders in pregnancy

The results of a joint workshop provide guidance on all aspects of substance use in pregnancy. Issues discussed in the full free text include screening tests, biologic tests, management of pain in labor and after Cesarean, pain after discharge, and approaches to medication assisted therapy (Methadone and Buprenorphine are standards of care), and organizational issues to optimize care. Discussion around breast feeding and the common neonatal opioid withdrawal syndrome (NOWS) occurs.

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ROTEM®‐guided algorithm in treatment of coagulopathy in obstetric haemorrhage

Point of Care coagulation assessments like ROTEM and TEG have been available for many years but data on outcome has been slower to emerge.

Hemorrhage management using traditional PT and PTT is a blunt instrument and has a slow laboratory turnaround time. Obstetric hemorrhage is different to trauma.

This is an obstetric hemorrhage report on 4 years of observational data from a tertiary care center using an algorithm based on FibTEM A5 assessment of hypofibrinogenemia. It resulted in a reduction in the number of units transfused and volume given, with less circulatory overload.

The authors note that coagulopathy is not observed in all women who suffer obstetric haemorrhage and cannot be predicted solely by blood loss, and also that women with placental abruption exhibited more severe coagulopathy and required higher doses of fibrinogen concentrate than women who bled due to other causes.

The results encourage point of care rather than formulaic blood product use to individualize cosgulopathy treatment.

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Norepinephrine vs. Phenylephrine in Cesarean

Norepinephrine has recently been increasingly studied for prophylaxis against hypotension during Cesarean Section under spinal anesthesia.

Phenylephrine has been shown to ameliorate hypotension and nausea/vomiting when given as a prophylactic infusion following spinal anesthesia.

This study compared the two agents and found Norepinephrine infusion effective and associated with less reactive hypertension and bradycardia. Neonatal outcomes were the same.

Norepinephrine rates were started at 0.05 mcg/Kg/min and Phenylephrine at 0.75 mcg/Kg/min.

This adds to growing evidence for Norepinephrine as an option in this scenario.

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Programmed Intermittent Epidural Bolus

Programmed intermittent epidural bolus (PIEB) has been touted as more effective than continuous or patient controlled epidural analgesia in labor. Studies are limited in this new area, often due to lack of pumps capable of delivering PIEB.

Under the conditions of this study, improved outcomes with programmed intermittent epidural boluses compared to continuous epidural infusion were not found, except for less motor block with programmed intermittent epidural boluses.

“Future studies should assess whether smaller but clinically important differences exist and evaluate different parameters of programmed intermittent epidural boluses to optimize analgesia and outcomes with this mode of analgesia”.

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Cesarean Maternal & Neonatal Mortality in Africa

Maternal mortality after cesarean delivery in Africa is 50 times higher than that of high-income countries and is driven by peripartum haemorrhage and anaesthesia complications. Neonatal mortality is double the global average.

These shocking figures from a prospective observational study across Africa may be due to such factors as poor access to caesarean delivery, peripartum hemorrhage, and provision of anesthesia by non-physicians.

Suggested areas to improve include risk identification (eg, ASA status, risk of bleeding), care bundles and checklists and a higher level of monitoring, use of antifibrinolytic drugs (tranexamic acid), improved access to blood and blood products with long shelf lives, such as freeze-dried plasma and fibrinogen; and novel methods of training of non-physician anaesthetists, including online support and mobile-based applications.

Prenatal surgery of fetal open spinal neural tube defects

A full text article describes some of the unique features of anesthesia for prenatal open and fetoscopic surgery of fetal open spinal neural tube defects.

For uterine relaxation, higher MACs of Sevoflurane were used, as well as nitroglycerin and tocolytics. Higher doses as well as greater hemodynamic disturbance occurred with open surgery. Colloids were used more, presumably to lower the risk of pulmonary edema which occurred in 10%, attributable to gestational physiologic changes, tocolytic administration and liberal fluid therapy.

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Intravenous Acetaminophen Before Pelvic Organ Prolapse Repair

This randomized study from the “green journal” compared preoperative intravenous acetaminophen 1g with placebo in women undergoing either laparoscopic or vaginal prolapse repair.

The findings were that “preoperative IV acetaminophen did not reduce pain scores or opioid use and had no effect on patient satisfaction or QOL. Routine use of preemptive IV acetaminophen alone is not supported by this study”.

This joins other studies showing little gain from intravenous acetaminophen.

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General Anesthesia for Cesarean

This retrospective study spanned a decade but included nearly half a million Cesarean Sections in New York State.

5.7% were classified as GA without a recorded indication. The study found: “The use of potentially avoidable general anesthesia in these patients is associated with an increased risk of anesthesia-related complications, surgical site infection, and venous thromboembolism, but not death or cardiac arrest”. The odds were quite significantly higher.

Risk factors for GA included age less than 19, racial or ethnic minority, Medicaid or Medicare beneficiaries, preexisting or pregnancy-associated conditions, nonelective admission, and admission during weekend, teaching hospital, neonatal level-of-care designation 1 or 3, lower use of neuraxial techniques during labor and vaginal deliveries, higher annual volume of deliveries, and higher proportion of women with a comorbidity index greater than 2.

Neuraxial anesthesia is established as the standard of care in Cesarean anesthesia absent contraindication. Higher labor epidural rates appeared to be the most actionable factor to encourage and increase the odds of neuraxial anesthesia.

Many of the other factors are either known or subject to the limitations of this retrospective study, and may be subject to coding inaccuracy, malfunctioning epidural catheters, or patient request.

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Cholecystectomy during Pregnancy

There has been a general opinion and comfort level with the safety of gall bladder surgery during pregnancy. One of the more reassuring findings in this study is that 90% were done after pregnancy, as the findings are not entirely supportive of existing recommendations.

They found “Women who have their gallbladder removed during pregnancy are more likely to experience longer hospital stays, increased 30-day readmissions, and higher rates of preterm delivery than those who delay the operation until after childbirth”. Pre-eclampsia and hemorrhage rates were also higher, as was open surgery.

It should be noted that they only studied third trimester vs. postpartum and not earlier during pregnancy. It certainly is possible that a subset of patients could benefit from cholecystectomy during pregnancy.

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Peripartum Cardiomyopathy

Of interest to obstetric anesthesiologists, a BMJ current review of this rare but serious dilated cardiomyopathy with systolic dysfunction that presents in late pregnancy or, more commonly, the early postpartum period.

Risk factors include black ancestry, pre-eclampsia, advanced maternal age, and multiple gestation pregnancy. Half recover but many more are left with chronic disease and a minority require mechanical support and/or transplantation.

Features are common to heart failure, and also include arrhythmias and thromboembolism (anticoagulation for which will impact neuraxial anesthesia). General treatment measures are discussed and potential specific treatments, including Bromocriptine for Prolactin inhibition, a postulated mechanism in etiology.

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