Obstetric anesthesia for the obese and morbidly obese patient: an ounce of prevention is worth more than a pound of treatment

The 90% effective dose of intrathecal hyperbaric bupivacaine for Cesarean delivery under combined spinal-epidural anesthesia in parturients with super obesity: an up-down sequential allocation study

PURPOSE

To determine the 90% effective dose (ED90) of intrathecal hyperbaric bupivacaine for Cesarean delivery under combined spinal-epidural anesthesia (CSE) in parturients with super obesity (body mass index [BMI] ≥ 50 kg·m-2).

METHODS

We enrolled parturients with BMI ≥ 50 kg·m-2 with term, singleton vertex pregnancies undergoing elective Cesarean delivery under CSE. An independent statistician generated the 0.75% hyperbaric bupivacaine dosing regimen in increments of 0.75 mg using a biased-coin up-down sequential allocation technique. This was combined with 15 μg fentanyl, 150 μg morphine, and normal saline to a volume of 2.05 mL. The initial and maximum doses were 9.75 mg and 12 mg, respectively. Participants, clinical team, and outcome assessors were blinded to the dose. The primary outcome was block success, defined as T6 block to pinprick within ten minutes and no intraoperative analgesic supplementation within 90 min of spinal injection. We determined the ED90 using logistic regression.

RESULTS

We enrolled 45 parturients and included 42 in the analysis. All doses achieved a T6 level within ten minutes, and the primary outcome occurred in 0/1 (0%) of the 9.75-mg doses, 2/3 (67%) of the 10.5-mg doses, 21/27 (78%) of the 11.25-mg doses, and 11/11 (100%) of the 12-mg doses. The ED90 of hyperbaric bupivacaine was 11.56 mg (95% confidence interval, 11.16 to 11.99). Four parturients (9.5%) had sensory level higher than T2, but none was symptomatic or required general anesthesia.

CONCLUSION

The estimated ED90 of hyperbaric bupivacaine with fentanyl and morphine in parturients with super obesity undergoing Cesarean delivery under CSE was approximately 11.5 mg.

STUDY REGISTRATION

ClinicalTrials.gov (NCT03781388); first submitted 18 December 2018.

Obesity at term: What to consider? How to deliver?

Obesity presents significant challenges during pregnancy, increasing the risk of complications and adverse outcomes for both mother and baby. With the rising prevalence of obesity among pregnant women, questions arise regarding optimal management, including timing of delivery and choice of delivery mode. Labour induction in obese women may require a combination of mechanical and pharmacological methods due to increased risk of failed induction. Caesarean section in obese women presents unique challenges, requiring comprehensive perioperative planning and specialized care to optimize outcomes. However, specific guidelines tailored to obese patients undergoing caesarean sections are lacking. Postpartum care should include vigilant monitoring for complications. Addressing obesity in pregnancy necessitates a multidisciplinary approach and specialized care to ensure the best outcomes.

Anesthesia and Analgesia for the Obese Parturient

Obesity is a worldwide epidemic and is associated with an increased risk of hypertension, diabetes, and obstructive sleep apnea. Pregnant patients with obesity experience a higher risk of maternal and fetal complications. Anesthesia also poses higher risks for obese parturients and may be more technically challenging due to body habitus. Safe anesthesia practice for these patients must take into consideration the unique challenges associated with the combination of pregnancy and obesity.

Effect of maternal body mass index on the prophylactic dose of phenylephrine for preventing hypotension in parturients after spinal anaesthesia

BACKGROUND

To compare the median effective dose (ED₅₀) of phenylephrine for prophylactic continuous infusion in parturients with different body mass indices (BMIs) during combined spinal-epidural anaesthesia for caesarean section and to investigate the impact of maternal BMI on the prophylactic dose of phenylephrine.

METHODS

Parturients receiving combined spinal-epidural anaesthesia for elective caesarean section were divided into a standard group (Group S, BMI < 30 kg/m²) and an obesity group (Group O, BMI > 30 kg/m²), each with 30 patients. A sequential allocation design was used to administer the prophylactic infusion of phenylephrine after the completion of a spinal anaesthetic injection to prevent hypotension (defined as a reduction of systolic blood pressure ≥ 20% of the baseline value or systolic blood pressure < 90 mmHg), with an initial infusion rate of 50 μg/min for the first parturient subsequent adjusted up or down by 10 μg/min depending on whether the previous parturient developed hypotension or not during the study period. The Dixon and Massey method and the isotonic regression method were used to calculate and compare the ED₅₀ and 95% confidence interval (CI) of phenylephrine between the two groups.

RESULTS

The results were 21.92 μg/min (95% CI, 14.90-28.94 μg/min) for Group S and 42.14 μg/min (95% CI, 24.58-59.70 μg/min) for Group O. The ratio of relative potency of Group O to Group S is 1.92 (95% CI 1.09 - 3.14), P = 0.034.

CONCLUSIONS

The dose of phenylephrine for the prevention of hypotension after spinal anaesthesia for caesarean section is dependent on maternal BMI. Therefore, a weight-based phenylephrine dose is reasonable.

Postoperative Respiratory Compromise following Cesarean Birth: The Impact of Obesity and Systemic Opioids

Objective  The aim of this study was to measure the effect of obesity and systemic opioids on respiratory events within the first 24 hours following cesarean. Methods  Opioid-naive women undergoing cesarean between January 2016 and December 2017 were included in this retrospective cohort study. The primary outcome was the proportion of women experiencing at least one composite respiratory outcome (oxygen saturation less than 95% lasting 30+ seconds or need for respiratory support) within 24 hours of cesarean. The impact of obesity and total systemic opioid dose in 24 hours (measured in morphine milligram equivalents [MMEs]) on the composite respiratory compromise outcome were evaluated. Results  Of 2,230 cesarean births, 790 women had at least one composite respiratory event. Predictors of the composite respiratory outcome included body mass index (BMI) as a continuous variable (odds ratio = 1.063 for every one unit increase in BMI [95% confidence interval (CI): 1.021-1.108], p  = 0.003), and MME (odds ratio = 1.005 [95% CI: 1.002-1.008], p  = 0.003), adjusting for magnesium sulfate use. The interaction between obesity and opioid dose demonstrated an odds ratio of 1.000 (95% CI: 0.999-1.000, p  = 0.030). Conclusion  The proportion of women experiencing respiratory events following cesarean birth increases with the degree of obesity and opioid dose. Key Points Respiratory events increase with obesity.Respiratory events increase with systemic opioid use.Odds ratio of respiratory events is 1.063/unit BMI increase.

The dynamic changes in the pattern of liver function tests in pregnant obese women

Obesity is an important problem in healthcare regarding gestating women. The objective of the present study was to highlight the impact that obesity has on the hepatic function in pregnant women by comparing the functional tests used in current practice. In addition, the aim was to identify possible predictors of liver damage by analyzing specific anthropometric data. The present study was descriptive, observational, retrospective, and based on the observation sheets found in the database of the Institute for the Health of the Mother and Child, the Obstetrics Gynecology Department of Polizu Hospital. Patients who presented for consultation in each trimester of pregnancy were included in the study. Demographic data taken into account included age, body mass index (BMI), provenance environment, anthropometric data: Abdominal circumference and the complete set of paraclinical data from which we extracted these specific liver tests: Aspartate aminotransferase (AST), alanine transferase (ALT), direct bilirubin (BD), serum albumin and gamma-glutamyl transferase (GGT). The present study included 157 patients divided into two groups, distributed as follows: Group A: 66 obese pregnant women (BMI >25 kg/m2) and group B: 91 patients with normal weight (BMI <25 kg/m2). Measurement of serum ALT and AST were the most useful tests for routine diagnosis of liver disease. The effects of pregnancy on serum levels of ALT and AST are controversial. In some studies, there was a slight increase in ALT and AST during the second and third trimesters, a fact confirmed by our study, albeit the result was not statistically significant Most published studies claim that serum ALT and AST levels do not change during pregnancy. In conclusion, obesity during pregnancy does not drastically influence liver function. However, patients with greater abdominal circumference are prone to developing minor hepatic cytolysis syndrome during the gestation period. The liver functional tests described in the aforementioned groups agree with the results provided by the specialized studies.

Spinal anesthesia for cesarean section in a super morbidly obese parturient: A case report

INTRODUCTION

The population of obese individuals is increasing worldwide, and as a result, the number of mothers with super morbid obesity undergoing cesarean sections is also increasing. However, little is known about which anesthetic technique is appropriate for cesarean sections of super morbidly obese parturients.

PATIENT CONCERNS

A 35-year-old woman with body mass index 61.3 kg/m at a gestational age of 37 weeks.

DIAGNOSIS

The patient was super morbidly obese parturient.

INTERVENTIONS

Spinal anesthesia was performed. A spinal needle was inserted into the L4-5 interspinous space in the sitting position. After confirmation of cerebrospinal fluid, 0.5% hyperbaric bupivacaine 9 mg and fentanyl 20 μg were injected into the subarachnoid space.

OUTCOMES

After the administration of spinal anesthetics, the nerve block to the T8 dermatome level was confirmed, surgery was performed, and the fetus was delivered. The patient's vital signs were stable until the end of the operation.

CONCLUSION

There is no established strategy for selecting a method of anesthesia in patients with morbid obesity (body mass index 40 kg/m or more). For this reason and considering the amount of bupivacaine used for spinal anesthesia, we wanted to share our experience with spinal anesthesia for cesarean section in a super morbidly obese parturients.

Pushing the Envelope in Obstetric Care: A Case Report of Cesarean Delivery in a Parturient with a BMI >100 kg m-2

An increasing number of women with a body mass index (BMI) ≥ 60 kg m⁻², referred to as super-super obesity, are requiring anesthetic care for labor and delivery. Management of these patients presents obstetric, anesthetic, and logistical challenges. We report our experience in the management of cesarean delivery in a parturient with a BMI of 112 kg m⁻². Use of epidural anesthesia and performance of a supraumbilical transverse surgical incision with caudal placement of the panniculus resulted in optimal hemodynamic and ventilatory parameters. Effective multidisciplinary planning and communication is key. We present this case to highlight decision-making strategies and elucidate our approach in the management of this complex obstetric case.

Anesthesia for Urgent Cesarean Section

Cesarean section (CS) is a common surgical procedure worldwide. The anesthesiologist is responsible, together with obstetrician and neonatologist, for safe perioperative management. A continuum of risk exists for urgent CS. The decision-to-delivery interval is an important audit tool, to ensure international standards are upheld and good outcomes for mother and neonate are achieved. Urgent CS may be performed under either GA or RA, with benefits and risks attributable to each. Specific clinical scenarios require an individualized approach to anesthesia, including hemorrhage, hypertensive disorders, cardiac disease, the difficult airway and fetal compromise. Ongoing training is integral to the provision of safe anesthesia.

Obesity And Obstetric Anesthesia: Current Insights

Obesity is a significant global health problem. It results in a higher incidence of complications for pregnant women and their neonates. Cesarean deliveries are more common in obese parturients as well. The increased burden of comorbidities seen in this population, such as obstructive sleep apnea, necessitates antepartum anesthetic consultation. These patients pose unique challenges for the practicing anesthesiologist and may benefit from optimization prior to delivery. Complications from anesthesia and overall morbidity and mortality are higher in this population. Neuraxial anesthesia can be challenging to place in the obese parturient, but is the preferred anesthetic for cesarean delivery to avoid airway manipulation, minimize aspiration risk, prevent fetal exposure to volatile anesthetic, and decrease risk of post-partum hemorrhage from volatile anesthetic exposure. Monitoring and positioning of these patients for surgery may pose specific challenges. Functional labor epidural catheters can be topped up to provide conditions suitable for surgery. In the absence of a working epidural catheter, a combined spinal epidural anesthetic is often the technique of choice due to relative ease of placement versus a single shot spinal technique as well as the ability to extend the anesthetic through the epidural portion. For cesarean delivery with a vertical supraumbilical skin incision, a two-catheter technique may be beneficial. Concern for thromboembolism necessitates early mobilization and a multimodal analgesic regimen can help accomplish this. In addition, thromboprophylaxis is recommended in this population after delivery—especially cesarean delivery. These patients also need close monitoring in the post-partum period when they are at increased risk for several complications.

Clinical evaluation of anesthesia for high-risk cesarean section at a tertiary medical center: retrospective study for 8 years (2009-2016)

Objective

The number of high-risk pregnancies is increasing in tertiary medical centers. Therefore, we investigated perioperative outcomes based on risk factors to ascertain proper maternal and neonatal management.

Methods

We reviewed the medical records of patients receiving cesarean sections over an 8-year period. Clinical parameters for anesthesia and the neonatal outcome were compared among high-risk groups after subdivision by the number of clinical risk factors. The groups were as follows: group A (one risk factor), group B (two risk factors), and group C (three or more risk factors).

Results

Patient age, estimated blood loss (EBL), and volume of transfused red blood cell (RBC) were higher in group B than group A. Birth weight, 1- and 5-minute Apgar scores, and gestational age were lower while the frequency of neonatal intensive care unit (NICU) admission was higher in group B than group A. Group C patients were significantly older than group A or B patients. Birth weight, 1- and 5-minute Apgar scores and gestational age were significantly lower while frequency of NICU admission was higher in group C than group A and B.

Conclusion

The number of maternal risk factors was positively associated with adverse outcomes in the neonates.

Anesthetic and obstetric outcomes in pregnant women undergoing cesarean delivery according to body mass index: Retrospective analysis of a single-center experience

Aim

To evaluate maternal, neonatal and anesthetic outcomes according to BMI in women undergoing cesarean section.

Background

Increased incidence rates of obesity and morbid obesity have been reported in the United States. Pregnant obese patients are at increased risk of maternal and fetal complications, and obstetric and anesthetic management of these patients is especially challenging.

Methods

A retrospective chart review of patients who underwent cesarean section in a single center between 2015 and 2016 was conducted. Anesthetic, obstetric and neonatal outcomes were analyzed in relation to levels of BMI.

Results

Seven hundred and seventy one patients underwent cesarean section during the study period. The number of patients with normal BMI, obesity and morbid obesity was 213 (27.6%), 365 (47.3%) and 193 (25%), respectively. Sixty-one percent of the patients in morbidly obese group had at least one comorbidity (p < 0.01). We found no significant differences with respect to perioperative obstetric complications. Intraoperative blood loss was significantly higher in the morbidly obese group.

Conclusion

Increasing BMI is associated with comorbidities such as hypertension and diabetes mellitus, and with increased intraoperative blood loss. We were unable to detect differences in other obstetric, anesthetic and neonatal outcomes.

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Incidence of morbid obesity is high in pregnancy.

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Morbid obesity is associated with medical and obstetric morbidities.

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Body mass index is associated with hypertension and diabetes mellitus in pregnant patients.

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Increased blood loss in cesarean section is associated with high body mass index.

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No significant maternal or anesthetic complications can be attributed solely to increasing body mass index.

Increasing body mass index and abdominal subcutaneous fat thickness are associated with increased skin-to-epidural space distance in pregnant women

BACKGROUND

Body mass index does not indicate the distribution of adipose tissue. Central adiposity may be measured using ultrasound measurement of subcutaneous fat thickness. This study determined if the abdominal subcutaneous fat thickness measured correlated with skin-to-epidural space distance at delivery, and compared this with the booking body mass index.

METHODS

We analysed a sub-set of participants from a single-centre, prospective cohort study that assessed the relationship between subcutaneous fat thickness and maternity outcomes. Abdominal subcutaneous fat thickness measurements were obtained during the routine fetal anomaly scan. The skin-to-epidural space distance was obtained in those having epidural or combined spinal-epidural analgesia. Linear regression was used to test for strength of association and adjusted R² values calculated to determine if subcutaneous fat thickness or body mass index was more strongly associated with skin-to-epidural space distance.

RESULTS

The 463 women had a median (IQR) booking body mass index of 25.0 kg/m² (21.8-29.3) and subcutaneous fat thickness of 16.2 mm (13.0-21.0). The median (IQR) skin-to-epidural space distance was 5.0 cm (4.5-6.0). Both parameters significantly correlated with skin-to-epidural space distance (r=0.53 and 0.68 respectively, P <0.001). Adjusted linear regression coefficient (95% CI) for subcutaneous fat thickness was 0.09 (0.08 to 0.11), R²=0.30 and for body mass index 0.12 (0.11 to 0.13), R²=0.47.

CONCLUSIONS

Booking body mass index had a stronger relationship with skin-to- epidural space distance at delivery than subcutaneous fat thickness, explaining 47% of the variation in the skin-to-epidural distance.

Relationship Between Body Mass Index and Spread of Spinal Anesthsia in Pregnant Women: A Randomized Controlled Trial

BACKGROUND The effect of body mass index (BMI) on the spread of spinal anesthesia is not completely clear. The aim of this study was to determine the dose requirements of ropivacaine and the incidence of hypotension in pregnant women with different BMIs during cesarean delivery. MATERIAL AND METHODS In this double-blind study, 405 women undergoing elective cesarean delivery were allocated to group S (BMI <25), group M (25 ≤BMI <30), or group L (BMI ≥30). Women in each group were further assigned to receive 7, 8, 9, 10, 11, 12, 13, 14, or 15 mg of spinal ropivacaine. RESULTS The ED50 and ED95 values of ropivacaine were 9.487 mg and 13.239 mg in Group S, 9.984 mg and 13.737 mg in Group M, and 9.067 mg and 12.819 mg in Group L. There were no significant differences among the 3 groups (p=0.915). Group L had a higher incidence of hypotension and a greater change in MAP after spinal anesthesia compared to the other 2 groups, and also required more doses of ephedrine than the other 2 groups when a dose of 15 mg ropivacaine was used. The incidence of hypotension had a positive correlation with the dose of ropivacaine (OR=1.453, p<0.001) and gestational age (OR=1.894, p<0.001). CONCLUSIONS Spinal ropivacaine dose requirements were similar in the normal BMI range. However, higher doses of spinal ropivacaine were associated with an increased incidence and severity of hypotension in obese patients compared with that in non-obese patients.

Assessment of venous hemodynamics and volume homeostasis during pregnancy: recommendations of the International Working Group on Maternal Hemodynamics

Venous hemodynamics and volume homeostasis are important aspects of cardiovascular physiology. However, today their relevance is still very much underappreciated. Their most important role is maintenance and control of venous return and, as such, cardiac output. A high-flow/low-resistance circulation, remaining constant under physiological circumstances, is mandatory for an uncomplicated course of pregnancy. In this article, characteristics of normal and abnormal venous and volume regulating functions are discussed with respect to normal and pathologic outcomes of pregnancy, and current (non-invasive) methods to assess these functions are summarized. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Epidural extension failure in obese women is comparable to that of non-obese women

BACKGROUND

Management of labor epidurals in obese women is difficult and extension to surgical anesthesia is not always successful. Our previous retrospective pilot study found epidural extension was more likely to fail in obese women. This study used a prospective cohort to compare the failure rate of epidural extension in obese and non-obese women and to identify risk factors for extension failure.

METHODS

One hundred obese participants (Group O, body mass index ≥ 40 kg/m² ) were prospectively identified and allocated two sequential controls (Group C, body mass index ≤ 30 kg/m² ). All subjects utilized epidural labor analgesia and subsequently required anesthesia for cesarean section. The primary outcome measure was failure of the labor epidural to be used as the primary anesthetic technique. Risk factors for extension failure were identified using Chi-squared and logistic regression.

RESULTS

The odds ratio (OR) of extension failure was 1.69 in Group O (20% vs. 13%; 95% CI: 0.88-3.21, P = 0.11). Risk factors for failure in obese women included ineffective labor analgesia requiring anesthesiologist intervention, (OR 3.94, 95% CI: 1.16-13.45, P = 0.028) and BMI > 50 kg/m² (OR 3.42, 95% CI: 1.07-10.96, P = 0.038).

CONCLUSION

The failure rate of epidural extension did not differ significantly between the groups. Further research is needed to determine the influence of body mass index > 50 kg/m² on epidural extension for cesarean section.

A review of blood pressure measurement in obese pregnant women

Blood pressure monitoring is a critical component of antenatal, peripartum and postnatal care. The accurate detection and treatment of abnormal blood pressure during pregnancy is essential for the optimisation of maternal and neonatal outcomes. Increasing maternal obesity in western populations is well documented. The presence of a large arm circumference in obese pregnant women may lead to difficult and inaccurate blood pressure measurements. Difficulties measuring blood pressure in non-pregnant obese patients are well described. In the literature, the problem is uncommonly mentioned in relation to pregnant patients. This topic review will discuss the importance and challenges of blood pressure measurement in pregnancy. The currently available equipment for blood pressure monitoring in pregnancy will be identified and the process of validating devices described. The limitations of the current validation protocols in pregnancy will be highlighted. It is concluded that a pregnancy-specific validation protocol is required: this would facilitate the introduction of new technology for use in high-risk pregnant women. More accurate blood pressure measurement has the potential to improve the diagnosis and management of abnormal blood pressure in pregnancy and influence maternal and neonatal outcomes.

A randomized trial of phenylephrine infusion versus bolus dosing for nausea and vomiting during Cesarean delivery in obese women

PURPOSE

Hypotension is common after spinal anesthesia for Cesarean delivery. It is associated with nausea, vomiting, and fetal acidosis. Previous research on phenylephrine excluded obese subjects. We compared the incidence of intraoperative nausea and vomiting (IONV) in obese patients who received a prophylactic phenylephrine infusion vs those who received bolus dosing for the treatment of spinal-induced hypotension.

METHODS

In this multicentre, double-blinded randomized controlled trial, 160 obese women undergoing elective Cesarean delivery under spinal anesthesia were randomized to receive a prophylactic phenylephrine infusion initiated at 50 μg·min^-1 (and titrated according to a predefined algorithm) or 100 μg phenylephrine boluses to treat hypotension. Maternal systolic blood pressure was maintained within 20% of baseline. The primary study outcome was the incidence of IONV.

RESULTS

Intraoperative nausea and vomiting were significantly reduced in the infusion group compared to the bolus group (46% vs 75%, respectively; relative risk [RR], 0.61; 95% confidence interval [CI], 0.47 to 0.80; P < 0.001). This was associated with significantly reduced need for intraoperative rescue antiemetics (26% vs 42%, respectively; RR, 0.62; 95% CI, 0.40 to 0.97; P = 0.04), but no difference in the incidence of vomiting. Postoperative vomiting at two hours was reduced in the infusion group (11% vs 25%; RR, 0.44; 95% CI, 0.21 to 0.90; P = 0.02);however, there were no differences in the incidence or severity of postoperative nausea, need for rescue antiemetics at two hours and 24 hr, or the incidence of postoperative vomiting at 24 hr.

CONCLUSION

In obese women undergoing Cesarean delivery with spinal anesthesia, prophylactic phenylephrine infusion was associated with less intraoperative nausea, less need for rescue antiemetics, and reduced early postoperative vomiting.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT01481740). Registered 22 July 2011.

Does obesity complicate regional anesthesia and result in longer decision to delivery time for emergency cesarean section?

BACKGROUND

Maternal obesity can cause problems with anesthesia and surgery which may be reflected in emergency cesarean sections (CS) as an increased decision-to-delivery interval (DDI).

AIM

To study the association of elevated maternal BMI with DDI and the failure of regional anesthesia.

METHODS

Eight hundred and forty-two consecutive emergency CSs during a period of 1 year in a tertiary hospital were studied retrospectively. DDIs were analyzed in Crash and < 30-min urgency categories (n = 528), while the time required to establish regional anesthesia and its success were analyzed for all emergency CS cases.

RESULTS

The urgency distribution of the CSs was 11%, 52%, and 37% in Crash, < 30-min, and > 30-min urgency categories respectively. Increased BMI was associated with longer DDI time in the < 30-min urgency category (33(13-176) vs. 38(18-118) min; P < 0.05 for BMI < 30 and > 35 group respectively). Regional anesthesia failures (new regional anesthesia, conversion to general anesthesia, or complaint of pain during surgery) took place in 3.7%, 6.8%, and 8.5% in the BMI < 30, 30-35, and > 35 groups respectively (P = 0.021). Epidural top-up resulted in shorter DDI and time delay between arrival at the operating room and skin incision across all urgency and BMI groups than combined spinal epidural (CSE) anesthesia.

CONCLUSION

Higher BMI was associated with longer DDI and more regional anesthesia failures. Epidural top-up was faster than CSE for establishing CS anesthesia.

Anaesthetists' experiences with the early labour epidural recommendation for obese parturients: a qualitative study

Caring for obese pregnant women presents challenges for all medical professionals. Despite a lack of supporting evidence, expert opinion and international guidelines suggest early labour epidural insertion for obese women. Anecdotally this is not supported by all anaesthetists. This qualitative study explored the experiences of anaesthetists regarding early epidural analgesia in obese parturients, to answer the research question: Are anaesthetists consistent in how they apply early epidural analgesia in obese parturients? Personal in-depth interviews with 42 specialist anaesthetists working in south-east Queensland, Australia, were completed between February and April, 2015. Leximancer™ text analysis software applied a validated algorithm to the data to identify themes and concepts. The major themes were explored by the first author to answer the research question. Three major themes were identified: the demands associated with caring for obese women; concern regarding the anaesthetic technique used in obese women; and the importance of communication with obstetric staff. Disagreement regarding interpretation and application of early epidural analgesia was identified within this group of anaesthetists. These anaesthetists were inconsistent in how they interpreted and applied early epidural analgesia for obese parturients, with some questioning the validity of the practice. The combination of uncertainty, urgency and technical difficulty presented by obese parturients provoked anxiety in these clinicians, particularly the anticipation of unplanned general anaesthesia. Consistent anaesthetic practice could improve the implementation of early epidural analgesia in obese parturients.

Cerebrospinal Fluid-Cutaneous Fistula After Continuous Spinal Catheter in an Obstetric Patient

A 23-year-old woman at 41 weeks and 6 days estimated gestational age underwent continuous spinal analgesia for labor after a recognized, unintended dural puncture. Excellent analgesia was maintained throughout labor and vaginal delivery, the intrathecal catheter was left in situ for 24 hours postpartum, and the catheter was subsequently removed without apparent complication. On physical examination during her anesthesia postoperative visit, clear fluid was noted to be slowly draining from the catheter insertion site. Although she denied all symptoms associated with a dural puncture, including headache, a cerebrospinal fluid-cutaneous fistula was diagnosed. An epidural blood patch was placed, which terminated the cerebrospinal fluid leak. No long-term complications were evident. Subsequent literature review revealed a rare incidence of this type of complication and varied recommendations for intervention and optimal management. We review the literature with regard to this complication and offer discussion regarding the various suggested means of diagnosis and therapy.

Increasing body mass index predicts increasing difficulty, failure rate, and time to discovery of failure of epidural anesthesia in laboring patients

STUDY OBJECTIVE

Obese parturients both greatly benefit from neuraxial techniques, and may represent a technical challenge to obstetric anesthesiologists. Several studies address the topic of obesity and neuraxial analgesia in general, but few offer well described definitions or rates of "difficulty" and "failure" of labor epidural analgesia. Providing those definitions, we hypothesized that increasing body mass index (BMI) is associated with negative outcomes in both categories and increased time needed for epidural placement.

DESIGN

Single center retrospective chart review.

SETTING

Labor and Delivery Unit of an inner city academic teaching hospital.

PATIENTS

2485 parturients, ASA status 2 to 4, receiving labor epidural analgesia for anticipated vaginal delivery.

INTERVENTIONS

None.

MEASUREMENTS

We reviewed quality assurance and anesthesia records over a 12-month period. "Failure" was defined as either inadequate analgesia or a positive test dose, requiring replacement, and/or when the anesthesia record stated they failed. "Difficulty" was defined as six or more needle redirections or a note indicating difficulty in the anesthesia record.

MAIN RESULTS

Overall epidural failure and difficulty rates were 4.3% and 3.0%, respectively. Patients with a BMI of 30kg/m² or higher had a higher chance of both failure and difficulty with two and almost three fold increases, respectively. Regression analysis indicated that failure was best predicted by BMI and less provider training while difficulty was best predicted by BMI. Additionally, increased BMI was associated with increased time of discovery of epidural catheter failure.

CONCLUSIONS

Obesity is associated with increasing technical difficulty and failure of neuraxial analgesia for labor. Practitioners should consider allotting extra time for obese parturients in order to manage potential problems.

Anesthetic Considerations in the Obese Parturient

The provision of anesthesia to the morbidly obese parturient is technically challenging. The anesthesia provider anticipates difficulty with intravenous access, positioning, monitoring, and placement of neuraxial anesthesia. There is a higher incidence of hypotension in obese parturients during neuraxial anesthesia most likely due to concealed aortocaval compression as positioning these patients is difficult. Most providers will provide either epidural or combined spinal/epidural anesthesia for cesarean delivery due to the variable duration of the surgical procedure. Among obese gravidas, there is a lower risk of the development of a headache from an accidental dural puncture, due not to the body habitus, but rather to the group's higher cesarean delivery rate. It is the process of bearing down during delivery that increases the chance of the development of a headache following dural puncture.

Perspectives in obesity and pregnancy

Obesity is currently recognized as a health epidemic worldwide. Its prevalence has doubled in the last three decades. Obesity is a complex clinical picture associated with physical, physiologic, hormonal, genetic, cultural, socioeconomic and environmental factors. The rate of obesity is also increasing in the pregnant women population. Maternal obesity is associated with less than optimal obstetrical, fetal and neonatal outcomes. It is also associated with significant adverse long-term effects on both obese parturients and the infants born from obese women. A number of guidelines have been published to educate health care workers and the general population in an attempt to develop effective interventions on a large scale to prevent obesity. These guidelines are multiple, confusing and inconsistent. There are no standard recommendations regarding gestational weight gaining goals, nutrients and additional elements necessary for certain obese women who have been treated with bariatric surgical procedures, screening for metabolic diseases such as diabetes, additional preventive health care services indicated for obese women in the pregnancy planning stages, during prenatal care, in the immediate post-partum period and as a long-term approach for health preservation. In 2013, the American Medical Association supported by several US national medical specialty organizations published Resolution 420 (A-13) recognizing obesity as a disease state with multiple pathophysiological aspects requiring a range of interventions to improve its prevention and treatment. The goal of this decision was to encourage a broader spectrum of health care benefits insurance coverage for the prevention and treatment of obesity. There are a number of myths and misconceptions associated with obesity. These perspectives present our views and clinical experience with a partial review of recent bibliography addressing the associations between obese reproductive age women and their risks during pregnancy.

Anaesthetic Management of Obese Parturients: What is the Evidence Supporting Practice Guidelines?

Increasing rates of obesity in western populations present management difficulties for clinicians caring for obese pregnant women. Various governing bodies have published clinical guidelines for the care of obese parturients. These guidelines refer to two components of anaesthetic care: anaesthetic consultation in the antenatal period for women with a body mass index (BMI) > 40 kg/m2 and the provision of early epidural analgesia in labour. These recommendations are based on the increased incidence of obstetric complications and the predicted risks and difficulties in providing anaesthetic care. The concept behind early epidural analgesia is logical—site the epidural early, use it for surgical anaesthesia and avoid general anaesthesia if surgery is required. Experts support this recommendation, but there is weak supporting evidence. It is known that the management of labour epidurals in obese women is complicated and that women with extreme obesity require higher rates of general anaesthesia. Anecdotally, anaesthetists view and apply the early epidural recommendation inconsistently and the acceptability of early epidural analgesia to pregnant women is variable. In this topic review, we critically appraise these two practice recommendations. The elements required for effective implementation in multidisciplinary maternity care are considered. We identify gaps in the current literature and suggest areas for future research. While prospective cohort studies addressing epidural extension (‘top-up’) in obese parturients would help inform practice, audit of local practice may better answer the question “is early epidural analgesia beneficial to obese women in my practice?”.

Obesity epidemic: impact from preconception to postpartum

The obesity epidemic is on the rise throughout the USA and the world. Not only does it affect the general population but it also specifically poses unique threats to a woman’s life in the antepartum, peripartum and postpartum periods. An increased BMI is associated with worse perinatal outcomes, including higher rates of preeclampsia (and other hypertensive disorders), macrosomia, other neonatal morbidities and gestational diabetes. Isolated maternal obesity and additional maternal diabetes predispose the infant to potential adult disease through fetal programming. This review of the literature examines the effects of obesity on a woman’s life, outlining complications beginning with preconception through the postpartum period.

Lay abstract: The obesity epidemic poses unique threats during the whole cycle of pregnancy. This review examines the effects of obesity on a woman’s life, outlining complications from prior to conception through the postpartum period. In addition, the contributions to adult disease of fetal exposure to this maternal risk are discussed. Future advances in nanotechnology and better understanding of placental function might allow more options in preventative and therapeutic interventions, yet with minimal fetal risk.

Managing anesthesia for cesarean section in obese patients: current perspectives

Obesity is a worldwide epidemic. It is associated with increased comorbidities and increased maternal, fetal, and neonatal complications. The risk of cesarean delivery is also increased in obese parturients. Anesthetic management of the obese parturient is challenging and requires adequate planning. Therefore, those patients should be referred to antenatal anesthetic consultation. Anesthesia-related complications and maternal mortality are increased in this patient population. The risk of difficult intubation is increased in obese patients. Neuraxial techniques are the preferred anesthetic techniques for cesarean delivery in obese parturients but can be technically challenging. An existing labor epidural catheter can be topped up for cesarean delivery. In patients who do not have a well-functioning labor epidural, a combined spinal epidural technique might be preferred over a single-shot spinal technique since it is technically easier in obese parturients and allows for extending the duration of the block as required. A continuous spinal technique can also be considered. Studies suggest that there is no need to reduce the dose of spinal bupivacaine in the obese parturient, but there is little data about spinal dosing in super obese parturients. Intraoperatively, patients should be placed in a ramped position, with close monitoring of ventilation and hemodynamic status. Adequate postoperative analgesia is crucial to allow for early mobilization. This can be achieved using a multimodal regimen incorporating neuraxial morphine (with appropriate observations) with scheduled nonsteroidal anti-inflammatory drugs and acetaminophen. Thromboprophylaxis is also important in this patient population due to the increased risk of thromboembolic complications. These patients should be monitored carefully in the postoperative period, since there is increased risk of postoperative complications in the morbidly obese parturients.

Risk factors for accidental dural puncture during epidural anesthesia for laboring women

BACKGROUND AND OBJECTIVES

Accidental dural puncture (ADP) during epidural analgesia is a debilitating complication. Symptoms of ADP post-dural puncture headache (PDPH) are headache while rising from supine to upright position, nausea, and neck stiffness. While age, gender and needle characteristics are established risk factors for ADP, little is known about risk factors in laboring women.

METHODS

All cases of ADP during epidural analgesia treated with blood-patching during a 3-years period were retrospectively reviewed. Each case was matched to two controls according to delivery period.

RESULTS

Forty-nine cases of blood patches after ADP out 17 977 epidural anesthesia procedures were identified (0.27%). No differences were found between cases and controls with regards to body mass index, labor stage at time of epidural, length of second stage, location of epidural along the lumbar vertebrae, anesthesiologist's experience or time when epidural was done. In cases of ADP, significantly lower doses of local anesthetics were injected (10.9 versus 13.5 cc, p < 0.001); anesthesiologists reported significantly more trials of epidurals (70 versus 2.8% more than one trial, p < 0.001), more patient movement during the procedure (13 versus 0%, p < 0.001), more intra-procedure suspicion of ADP (69 versus 0%, p < 0.001) and more cases where CSF/blood was drawn with the syringe (57 versus 2.4%, p < 0.001).

CONCLUSION

ADP during labor is a rare but debilitating complication. Risk factors for this iatrogenic complication include patient movement and repeated epidural trials. Intra-procedure identification of ADP is common, allowing early intervention with blood patching where indicated.

Management of a Rare Complication of Epidural Analgesia in an Obese Laterally Positioned Parturient: Catheter Entrapment Next to the Inferior Vena Cava

Intravascular, subdural, intrathecal, and subcutaneous placement of epidural catheters are known complications and common causes of anesthesia and analgesia failure. Because the epidural space is located near the retroperitoneum and catheters are placed blindly, it is possible that misplacement could involve other structures, including the inferior vena cava, the aorta, and the lumbar plexus. We report a case of an obese laterally positioned parturient who presented with an epidural catheter lodged in the retroperitoneum. The catheter provided inadequate analgesia for labor, and postpartum computed tomography revealed it to be located in the retroperitoneal space just adjacent to the inferior vena cava. Conventional removal techniques were unsuccessful, and the catheter was finally removed after insertion of a guide wire under fluoroscopy. We conclude that obesity and lateral positioning are factors that increase the risk of epidural catheter misplacement, and a large distance from skin to loss of resistance is a potential sign of misplacement. We recommend ultrasound imaging to aid in the insertion of epidural catheters in high-risk patients.

Neuraxial Anesthesia in Parturients with Thrombocytopenia: A Multisite Retrospective Cohort Study

BACKGROUND

The primary aim of this study was to estimate the risk of neuraxial hematoma associated with neuraxial anesthetic procedures in thrombocytopenic parturients.

METHODS

A multicenter retrospective cohort study design was used to estimate the risk for spinal-epidural hematoma in parturients with a platelet count of <100,000/mm receiving neuraxial anesthesia and the risk of complications in thrombocytopenic parturients who receive general anesthesia.

RESULTS

No cases of spinal hematoma were observed in 102 thrombocytopenic parturients receiving epidural analgesia or 71 receiving spinal anesthesia. Including data from the previous published series (total n = 499), the exact binomial 95% confidence interval for the risk of spinal-epidural hematoma was 0% to 0.6%. Given the small number of patients at each specific platelet count, the theoretical risks at individual platelet count strata are presented. Overall aggregate serious morbidity rate in women who received general anesthesia secondary to thrombocytopenia was 6.5% (95% confidence interval, 2.1%-14.5%).

CONCLUSIONS

Our work supports the relative maternal safety of neuraxial anesthesia in parturients with mild thrombocytopenia and estimates the maternal complication rate associated with the avoidance of neuraxial anesthesia. Remaining uncertainties at lower platelet counts make a national "low platelet" registry critical to a more accurate assessment of the risk of epidural hematoma and would aid in standardization of anesthesia practice.

Blood volume determination in obese and normal-weight gravidas: the hydroxyethyl starch method

OBJECTIVE

The impact of obesity on maternal blood volume in pregnancy has not been reported. We compared the blood volumes of obese and normal-weight gravidas using a validated hydroxyethyl starch (HES) dilution technique for blood volume estimation.

STUDY DESIGN

Blood volumes were estimated in 30 normal-weight (pregravid body mass index [BMI] <25 kg/m(2)) and 30 obese (pregravid BMI >35 kg/m(2)) gravidas >34 weeks' gestation using a modified HES dilution technique. Blood samples obtained before and 10 minutes after HES injection were analyzed for plasma glucose concentrations after acid hydrolysis of HES. Blood volume was calculated from the difference between glucose concentrations measured in hydrolyzed plasma.

RESULTS

Obese gravidas had higher pregravid and visit BMI (mean [SD]): pregravid (41 [4] vs 22 [2] kg/m(2), P = .001); visit (42 [4] vs 27 [2] kg/m(2), P = .001), but lower weight gain (5 [7] vs 12 [4] kg, P = .001) than normal-weight women. Obese gravidas had similar estimated total blood volume to normal-weight women (8103 ± 2452 vs 6944 ± 2830 mL, P = .1), but lower blood volume per kilogram weight (73 ± 22 vs 95 ± 30 mL/kg, P = .007).

CONCLUSION

Obese gravidas have similar circulating blood volume, but lower blood volume per kilogram body weight, than normal-weight gravidas near term.

What is the failure rate in extending labour analgesia in patients with a body mass index ≥ 40 kg/m(2)compared with patients with a body mass index < 30 kg/m(2)? a retrospective pilot study

BACKGROUND

Early utilisation of neuraxial anaesthesia has been recommended to reduce the need for general anaesthesia in obese parturients. The insertion and management of labour epidurals in obese women is not straight-forward. The aim of this pilot study was to compare the failure rate of extension of epidural analgesia for emergency caesarean section, in pregnant women with a body mass index (BMI) ≥ 40 kg/m(2), to those with a BMI < 30 kg/m(2). The results will be used to calculate the sample size of a planned prospective study.

METHODS

In this retrospective, (1:1) case-control pilot study, obese subjects and control subjects were selected from the obstetric database, if they delivered between January 2007 and December 2011. All subjects used epidural analgesia during labour and subsequently required anaesthesia for Category 1 or 2 Caesarean Section. Data was extracted from the patient medical record. Failure to extend was analysed using liberal and restrictive definitions. Chi-square or Fisher's exact tests were used to detect differences between groups. Multiple logistic regression was used to examine variables predictive of extension failure.

RESULTS

There were 63 subjects in each group. The mean BMI of the obese group was 45.4 (5.8) kg/m(2) and 23.9 (3.0) kg/m(2) in the control group. The odds ratio for failure to extend the existing epidural blockade (liberal definition) was 2.48 (95 % CI:1.02 - 6.03) for the obese group compared with the control group (adjusted for age, parity and gestation). Using the restrictive definition, the odds ratio for failure in the obese group was 6.78 (95 % CI:1.43 - 32.2). The combination of respiratory co-morbidity and gestational diabetes significantly predicted extension failure. Surgical time and epidural complications on labour ward were significantly greater in the obese group.

CONCLUSIONS

In this small retrospective cohort, patients with a BMI ≥ 40 kg/m(2) were significantly more likely to fail epidural extension for caesarean section. The presence of respiratory co-morbidity and gestational diabetes were significant predictors of extension failure; their clinical relevance requires further evaluation.

Is ultrasonic investigation of transverse tracheal air shadow diameter reasonable for evaluation of difficult airway in pregnant women: A prospective comparative study

Objective: The aim of this study was to compare clinical screening tests (modified Mallampati score, Cormack-Lehane score, thyromental distance, and sternomental distance) with ultrasonic measurements of the upper airway in predicting difficult intubation in pregnant women whose Body Mass Index (BMI) is higher and lower than 30 kg m-2.

Methods: This study was designed as a prospective observational trial, and consisted of 40 pregnant women of American Society of Anesthesiologists (ASA) 1-2 groups. Patients with a BMI lower than 30 kg m-2 were included in Group 1 (n=20), and patients with a BMI higher than 30 kg m-2 were included in Group 2 (n=20). In the supine position with head in mild extension, the diameter of the transverse tracheal air shadow in the subglottic area of the front neck was measured using ultrasonography. Modified Mallampati score, Cormack-Lehane score, thyromental distance and sternomental distance measurements were recorded.

Results: No statistically significant difference was detected between groups regarding mean age, mean number of pregnancy, ASA scores and comorbid disease. Mean body weight (p=0.0001) and mean pre-pregnancy weight (p=0.0001) were significantly higher in Group 2. There was no statistically significant difference between groups regarding mean modified Mallampati score, thyromental distance, sternomental distance measurements, Cormack-Lehane score, and mean ultrasonic measurements.

Conclusion: It was found that BMI higher or lower than 30 kg m-2 has no effect on ultrasonic measurements and clinical airway tests. We thought that ultrasonic measurement could not give us valuable information in obese or non-obese pregnant women.

[New aspects of obstetric anesthesia]

BACKGROUND

The risk profile of patients in obstetric anesthesia has substantially changed. Even more so than other disciplines, obstetric anesthesia is therefore in the true sense of the word dependent on the close coordination of all concerned and a good interdisciplinary cooperation.

AIM

This article explains the important anesthesiological risks connected with parturition and presents the corresponding concepts for prevention, diagnosis and management of peripartum complications.

MATERIAL AND METHODS

The increase in the number of high risk pregnancies, which are mostly due to an increase in obesity, require clearly defined guidelines and interdisciplinary concepts which are described and discussed in this article. The neuraxial block is still the most effective procedure for treatment of birth pain and offers a promising new method with the programmed intermittent epidural boluses presented in this article. Finally, the German speaking countries Germany, Austria and Switzerland have developed a treatment algorithm for the management of postpartum hemorrhage which is presented here.

RESULTS

The anesthesiological components of a risk pregnancy must be recognized early and include obesity, preeclampsia and drug-induced coagulopathy. Epidural analgesia is the most effective analgesic procedure in obstetrics. Patient-controlled remifentanil analgesia currently represents the best alternative in cases of contraindications for a neuraxial procedure.

CONCLUSION

In risk situations, such as pre(eclempsia), emergency cesarean section, massive blood loss or other peripartum emergency situations, optimal interdisciplinary cooperation between midwives, obstetricians and anesthetists is required. However, not only emergency situations require a good interdisciplinary cooperation. Just as important is the cooperation to recognize risk pregnancies and a timely joint planning of the approaching birth.

Peripartum anesthetic management of renal transplant patients--a multicenter cohort study

As the number and success of renal transplantation has grown, there has been an increase in the number of renal transplant patients giving birth. To date, there has been no data on obstetric anesthesia management of these patients. The purpose of this study was to build an Israeli national database on parturients after renal transplant. A sixteen-year (calendar years 1996-2011) retrospective study was conducted at three major tertiary centers with a combined current birth rate of approximately 25,000 deliveries annually. We found 83 labors in 64 women. Forty-two percent of this population suffered from hypertension while 12.5% had diabetes. Forty-seven percent of women had a vaginal delivery while 53% of women had a cesarean section. The rate of epidural analgesia for labor was 59%, and rate of regional anesthesia during cesarean section was 75%. There were no anesthetic complications in any cases. Standard ASA monitoring was used in all cases except for one woman with severe hypertension who required an arterial line during her cesarean section. Forty-seven percent of newborn were under 37 weeks with average gestational week 36 ± 3 days and birth weight 2.5 ± 0.7 kg. Average Apgar was 8.4 ± 1.3 at one minute and 9.3 ± 0.7 at five minutes. There was one neonatal death in the CS group due to placental abruption. Patients after renal transplant can safely undergo birth and obstetric analgesia.

Efficacy and safety of remifentanil as an alternative labor analgesic

The objective of this review was to evaluate the clinical efficacy and safety of remifentanil in the management of labor pain. Although neuraxial analgesia is the best option during labor, alternative analgesic options are needed for patients with contraindications. Using a systematic literature search, clinical outcomes of remifentanil for labor pain have been summarized. Also, comparisons of remifentanil to other options including meperidine, epidural analgesia, fentanyl, and nitrous oxide are provided. Based on the literature review, remifentanil is associated with high overall maternal satisfaction and favorable side-effect profile. However, due to the low reporting of adverse events, large, randomized controlled trials are needed to evaluate maternal and neonatal safety adequately and determine the optimal dosing needed to provide effective analgesia. While remifentanil is a feasible alternative for patients who cannot or do not want to receive epidural analgesia, administration should be monitored closely for potential adverse effects.

Anesthetic considerations of parturients with obesity and obstructive sleep apnea

Obstructive sleep apnea (OSA) is characterized by upper airway collapse and obstruction during sleep. It is estimated to affect nearly 5% of the general female population. Obesity is often associated with OSA. The physiological changes associated with pregnancy may increase the severity of OSA with a higher risk of maternal and fetal morbidity. However, very few parturients are diagnosed during pregnancy. These undiagnosed parturients pose great challenge to the attending anaesthesiologist during the perioperative period. Parturients at risk should be screened for OSA, and if diagnosed, treated. This review describes the anaesthetic concerns in obese parturients at risk for OSA presenting to the labor and delivery unit.