Anesthetic Considerations in the Obese Parturient

Performance of the ratio of posterior complex length to depth measured by ultrasound as a predictor of difficult spinal anesthesia for elective cesarean delivery: a prospective cohort study

PURPOSE

Ultrasound view of the interlaminar structure is likely to be associated with difficult spinal anesthesia (DSA), and a poor ultrasound view which cannot show the anterior and posterior complex predicts a difficult spinal technique. As our target site is the posterior complex, this study aimed to assess whether the ratio of posterior complex length to depth measured by ultrasound can predict DSA in cesarean delivery.

METHODS

Four anesthesiologists with 1-2 years of experience located and marked the puncture interspace using a traditional surface landmark. Subsequently, the ultrasound examiner located and measured the marked interspace via an oblique parasagittal ultrasound scan. The anesthesiologists, who were blinded to the ultrasound results, performed spinal anesthesia using a 25-gauge Whitacre spinal needle. The total number of attempts, including skin punctures and needle passes, was recorded and the DSA was defined as 10 unsuccessful attempts. A multivariable logistic regression analysis was used to determine the independent predictors, and receiver operating characteristic curves were constructed to evaluate the performance of the ratio of posterior complex length to depth for predicting DSA.

RESULTS

A total of 397 cesarean delivery parturients with successfully measured posterior complex were included in the analysis. DSA occurred in 64 parturients (16.1%). Reduced length [odds ratio (OR) = 0.010, 95% confidence interval (CI), 0.002-0.062, P < 0.001] and increased depth [OR = 6.127, 95% CI, 2.671-14.056, P < 0.001] of the posterior complex were independently predictive of DSA compared with body mass index, abdominal circumference, and palpable surface landmarks. The ratio of posterior complex length to depth for predicting DSA had an area under the curve of 0.86 (95% CI, 0.82-0.90). The optimal cutoff was 0.23, with a sensitivity of 86% (95% CI, 74-93%) and specificity of 72% (95% CI, 67-77%).

CONCLUSION

The ratio of posterior complex length to depth measured by ultrasound demonstrated a considerable accuracy in predicting DSA for inexperienced anesthesiologists. A higher ratio at ultrasound is an indication to evaluate the optimal puncture body position and interspace in the clinic practice.

CLINICAL TRIAL REGISTRATION

ChiCTR2200065171 https://www.chictr.org.cn/showproj.html?proj=180855.

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.

Effects of obesity indices/GDM on the pregnancy outcomes in Chinese women: A retrospective cohort study

OBJECTIVE

To analyze pregnancy complications and outcomes of mothers with obesity or gestational diabetes mellitus (GDM).

METHODS

15065 mothers were categorized into four and three groups by pre-pregnancy body mass index (preBMI) and abdominal circumference (AC), respectively, or divided into GDM or non-GDM groups. Logistic regression analysis was utilized to identify independent factors associated with pregnancy complications and outcomes.

RESULTS

The overweight and obesity groups accounted for 16.0% and 4.0% of the total population, respectively. GDM incidence rate was 12.3%. The overweight and obesity groups (pre-pregnancy body mass index [preBMI] ≥ 24 kg/m²) were at higher risks for GDM, hypertensive disorders of pregnancy (HDP), gestational proteinuria, postpartum hemorrhage, preterm delivery, fetal malformation or stillbirth, neonatal asphyxia, large for gestational age (LGA), shoulder dystocia, and increased cesarean section rate. Similar results were obtained with AC grouping. GDM pregnant women had higher risks of HDP, preterm delivery, small for gestational age (SGA), LGA, and increased cesarean section rate.

CONCLUSION

People with obesity had a higher risk of adverse pregnancy outcomes. The recommended preBMI is 19.2-22.7 kg/m². The recommended AC at 11-13⁺⁶ gestational weeks is 74.0-84.0 cm, and that value in normal preBMI is 74.0-82.0 cm.

Comparison of different approaches to combined spinal epidural anesthesia (CSEA) under the guidance of ultrasound in cesarean delivery of obese patients: a randomized controlled trial

Background

Combined spinal epidural anesthesia (CSEA) is commonly performed in cesarean deliveries. However, it is difficult to perform in obese parturients because of positioning challenges. The aim of this study was to compare the effect of different approaches to CSEA under the guidance of ultrasound.

Methods

One hundred obese patients (BMI ≥ 30 kg/m²) who underwent elective cesarean section were randomly enrolled. Patients were assigned to a median approach group and a paramedian approach group randomly. Clinical characteristics were compared between groups. First-attempt success rate, the median positioning time and total operation time, ultrasonic predicted anesthesia puncture depth, actual puncture depth, anesthesia adverse reactions, complications after anesthesia, and patients’ satisfaction with the epidural puncture were recorded.

Results

The first-attempt success rate was significantly different between the two groups [92% (46/50) vs. 76% (38/50), P  =  0.029]. The median positioning time and total operation time in the paramedian approach group were higher than those in the median approach group (227.7 s vs. 201.6 s, P  =  0.037; 251.3 s vs. 247.4 s, P  =  0.145). The incidence of postanesthesia complications in the paramedian approach group was significantly lower than that in the median approach group (2% vs. 12%, P  =  0.026), and patient satisfaction was higher in the paramedian approach group than in the median approach group (P  =  0.032).

Conclusion

The ultrasound-guided paramedian approach for CSEA is time-consuming, but it can effectively improve the success rate of the first puncture, reduce the incidence of anesthesia-related adverse reactions, and improve patient satisfaction.

Trial registration: This study was registered with the Chinese Clinical Trial Registry (ChiCTR1900024722) on July 24, 2019

Cesarean Delivery in a Patient With Body Mass Index Over 100: Continuous Spinal Anesthesia in Two Consecutive Deliveries

Anesthetic implications for morbidly obese parturients have been well described; however, the literature has not yet clarified whether there are additional or unique concerns if the body mass index (BMI) rises farther above the so-called super morbid obesity level: BMI >50 kg/m². There have only been a few case reports focusing on patients with BMI close to or above 100. Parturients with BMI significantly greater than 50 are uncommon, but they represent an increasing proportion among the morbidly obese. In this report, we present the use of continuous spinal anesthesia in consecutive cesarean deliveries for a patient with a BMI of 102 at her first delivery and 116 at her second. For both deliveries, an intrathecal catheter dosing incrementally provided effective anesthesia with a cumulative dose of hyperbaric bupivacaine 12 mg, fentanyl 15 mcg, and morphine 100 mcg given in 0.25-ml increments over 12 minutes, with 0.25-ml sterile saline flushes between doses. While dosing the catheter, the patient was gradually lowered to a 30° semi-recumbent position for surgery. This strategy minimized the risk of high spinal block or respiratory distress. She did not develop any postdural puncture headache (PDPH). This case report offers an extreme example and provides estimates towards adjusting staffing, equipment, location, timing, positioning, anesthetic technique, and dosing for cesarean deliveries in patients with very high BMI levels.

Anesthetic Management of a Super Morbidly Obese Obstetric Patient With a Body Mass Index of 109 kg/m2 Presenting for Her Fourth Caesarean Delivery

Morbidly obese obstetric patients undergoing anesthesia present many unique challenges. Previous caesarean sections (CSs) further complicate their management. We present the successful anesthetic management of a super morbidly obese obstetric patient with body mass index (BMI) of 109 kg/m² who underwent her fourth CS. As per our review, this patient has the highest recorded BMI in the obstetric anesthesia literature.

A 27-year-old female, G4P3003, presented for fourth repeat CS at 38 weeks’ gestation. She had obstructive sleep apnea, hypertension, atrial fibrillation, and type 2 diabetes. Her first CS was emergent under general anesthesia (GA), and the other two were performed under neuraxial anesthesia, with the most recent one complicated by intraoperative cardiac arrest requiring cardiopulmonary resuscitation. Preoperative preparation involved multidisciplinary preparation, planning, and risk stratification. Although neuraxial anesthesia is preferred over GA for CS, she refused neuraxial anesthesia due to her prior traumatic experience and the potential that it caused her prior cardiac arrest. In addition, her inability to position for a block or lay flat, poor anatomical landmarks, unknown length of surgery, plan for periumbilical incision, uncertain placental status, and risk of massive hemorrhage convinced us to consider GA. Surprisingly, her airway examination was reassuring. Two 18G peripheral intravenous lines and an arterial line were obtained prior to induction. With optimum patient positioning and preoxygenation, modified rapid sequence induction with mask ventilation and endotracheal intubation with direct laryngoscopy were performed. A healthy baby was delivered without significant intraoperative complications. Intraoperative lung-protective strategy with recruitment maneuvers, multimodal analgesia, and elective postoperative continuous positive airway pressure aided in successful extubation. Postoperatively, pulmonary toilet, early mobilization, physical therapy, and venous thromboembolism prophylaxis were employed. Her postoperative course was complicated by severe preeclampsia and pulmonary embolism, which were managed successfully in the intensive care unit. She was discharged initially to outpatient rehabilitation followed by home. This case highlights the complexities and significance of an individualized approach in managing super morbidly obese obstetric patients.

Observation of hemodynamic parameters using a non-invasive cardiac output monitor system to identify predictive indicators for post-spinal anesthesia hypotension in parturients undergoing cesarean section

The administration of high-level spinal anesthesia for cesarean section may lead to significant hemodynamic changes. Bioreactance-based non-invasive cardiac output monitoring (NICOM^™) provides an accurate monitoring system for parturients under spinal anesthesia. The present study hypothesized that baseline hemodynamic parameters obtained via the NICOM^™ system could serve as predictive indicators for post-spinal anesthesia hypotension. Therefore, 80 full-term parturients with singleton pregnancies who underwent scheduled cesarean section were enrolled and allocated to either a supine position group or a 15˚ left tilt group. All parturients received standard pre-hydration with 750 ml of 0.9% saline. Baseline cardiac output index (CI), total peripheral resistance index (TPRI) and stroke volume (SV) were recorded using the NICOM^™ system. Subsequently, spinal anesthesia with 2.4 ml of 0.5% hyperbaric bupivacaine, 10 µg of fentanyl and 0.2 mg of morphine was administered. Receiver operating characteristic (ROC) curves and multivariate logistic regression were used to analyze the data. A total of 40 parturients (51.9%) developed hypotension. The areas under the ROC curves were 0.666, 0.594 and 0.622 for the CI, TPRI and SV, respectively. The optimal cut-off value of the CI in predicting hypotension was 3.68 l/min/m² (ROC, sensitivity=85.0%, specificity=48.6%). Furthermore, CI was considered as an independent factor for post-spinal anesthesia hypotension. In conclusion, the baseline CI obtained via the bioreactance-based NICOM^™ system may serve as a predictor of post-spinal anesthesia hypotension in parturients regardless of patient position.

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.

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.

Peripartum Anesthesia Considerations for Placenta Accreta

Placenta accreta spectrum is becoming more common and is the most frequent indication for peripartum hysterectomy. Management of cesarean delivery in the setting of a morbidly adherent placenta has potential for massive hemorrhage, coagulopathies, and other morbidities. Anesthetic management of placenta accreta spectrum presents many challenges including optimizing surgical conditions, providing a safe and satisfying maternal delivery experience, preparing for massive hemorrhage and transfusion, preventing coagulopathies, and optimizing postoperative pain control. Balancing these challenging goals requires meticulous preparation with a thorough preoperative evaluation of the parturient and a well-coordinated multidisciplinary approach in order to optimize outcomes for the mother and fetus.

Guidelines for Antenatal and Preoperative care in Cesarean Delivery: Enhanced Recovery After Surgery Society Recommendations (Part 1)

This Enhanced Recovery After Surgery (ERAS) Guideline for perioperative care in cesarean delivery will provide best practice, evidenced-based, recommendations for preoperative, intraoperative, and postoperative phases with, primarily, a maternal focus. The focused pathway process for scheduled and unscheduled cesarean delivery for this ERAS Cesarean Delivery Guideline will consider from the time from decision to operate (starting with the 30-60 minutes before skin incision) to hospital discharge. The literature search (1966-2017) used Embase and PubMed to search medical subject headings that included "Cesarean Section," "Cesarean Section," "Cesarean Section Delivery" and all pre- and intraoperative ERAS items. Study selection allowed titles and abstracts to be screened by individual reviewers to identify potentially relevant articles. Metaanalyses, systematic reviews, randomized controlled studies, nonrandomized controlled studies, reviews, and case series were considered for each individual topic. Quality assessment and data analyses that evaluated the quality of evidence and recommendations were evaluated according to the Grading of Recommendations, Assessment, Development and Evaluation system, as used and described in previous ERAS Guidelines. The ERAS Cesarean Delivery Guideline/Pathway has created a maternal focused pathway (for scheduled and unscheduled surgery starting from 30-60 minutes before skin incision to maternal discharge) with ERAS cesarean delivery consensus recommendations preoperative elements (anesthetic medications, fasting, carbohydrate supplementation, prophylactic antibiotics/skin preparation, ), intraoperative elements (anesthetic management, maternal hypothermia prevention, surgical technique, hysterotomy creation and closure, management of peritoneum, subcutaneous space, and skin closure), perioperative fluid management, and postoperative elements (chewing gum, management of nausea and vomiting, analgesia, timing of food intake, glucose management, antithrombotic prophylaxis, timing of ambulation, urinary management, and timing of maternal and neonate discharge). Limited topics for optimized care and for antenatal education and counselling and the immediate neonatal needs at delivery are discussed. Strong recommendations for element use were given for preoperative (antenatal education and counselling, use of antacids and histamine, H2 receptor antagonists, 2-hour fasting and small meal within 6 hours surgery, antimicrobial prophylaxis and skin preparation/chlorhexidine-alcohol), intraoperative (regional anesthesia, prevention of maternal hypothermia [forced warm air, warmed intravenous fluids, room temperature]), perioperative (fluid management for euvolemia and neonatal immediate care needs that include delayed cord clamping), and postoperative (fluid management to prevent nausea and vomiting, antiemetic use, analgesia with nonsteroidal antiinflammatory drugs/paracetamol, regular diet within 2 hours, tight capillary glucose control, pneumatic compression stocking for venous thromboembolism prophylaxis, immediate removal of urinary catheter). Recommendations against the element use were made for preoperative (maternal sedation, bowel preparation), intraoperative (neonatal oral suctioning or increased inspired oxygen), and postoperative (heparin should not be used routinely venous thromboembolism prophylaxis). Because these ERAS cesarean delivery pathway recommendations (elements/processes) are studied, implemented, audited, evaluated, and optimized by the maternity care teams, this will create an opportunity for the focused and optimized areas of care research with further enhanced care and recommendation.

Peripartum Management of Obstructive Sleep Apnea

The prevalence of obstructive sleep apnea is unknown during pregnancy, but the syndrome is likely underdiagnosed and rising in frequency along with the obesity epidemic. Obstructive sleep apnea is associated with adverse outcomes, including hypertensive disorders of pregnancy, gestational diabetes, preterm, and cesarean delivery. Obese pregnant women should be screened and referred to a sleep medicine specialist for evaluation. Continuous positive airway pressure is the treatment of choice with demonstrated safety and compliance in pregnancy. Early anesthesia consultation allows for preparation and implementation of a peripartum plan that includes early labor analgesia, avoidance of respiratory depressants, and closer monitoring of oxygenation.