Mechanisms and management of an incomplete epidural block for cesarean section

Ultrasound-guided caudal anaesthesia combined with epidural anaesthesia for caesarean section: a randomized controlled clinical trial

BACKGROUND

Although epidural anaesthesia and spinal anaesthesia are currently the general choices for patients undergoing caesarean section, these two neuraxial anaesthesia methods still have drawbacks. Caudal anaesthesia has been considered to be more appropriate for gynaecological surgery. The purpose of this study was to compare epidural anaesthesia combined with caudal anaesthesia, spinal anaesthesia and single-space epidural anaesthesia for caesarean section with respect to postoperative comfort and intraoperative anaesthesia quality.

METHODS

In this clinical trial, 150 patients undergoing elective caesarean section were recruited and randomized into three groups according to a ratio of 1:1:1to receive epidural anaesthesia only, spinal anaesthesia only or epidural anaesthesia combined with caudal anaesthesia. The primary outcome was postoperative comfort in the three groups. Secondary outcomes included intraoperative anaesthesia quality and the incidences of nausea, vomiting, postdural puncture headache, maternal bradycardia, or hypotension.

RESULTS

More patients were satisfied with the intraoperative anaesthesia quality in the EAC group than in the EA group (P = 0.001). The obstetrician was more significantly satisfied with the intraoperative anaesthesia quality in the SA and EAC groups than in the EA group (P = 0.004 and 0.020, respectively). The parturients felt more comfortable after surgery in the EA and EAC groups (P = 0.007). The incidence of maternal hypotension during caesarean section was higher in the SA group than in the EA and EAC groups (P = 0.001 and 0.019, respectively).

CONCLUSIONS

Epidural anaesthesia combined with caudal anaesthesia may be a better choice for elective caesarean section. Compared with epidural anaesthesia and spinal anaesthesia, it has a higher quality of postoperative comfort and intraoperative anaesthesia.

Risk factors for labor epidural conversion failure requiring general anesthesia for cesarean delivery

Background and Aims:

To evaluate the rate and risk factors of labor epidural conversion failure requiring general anesthesia for Caesarean delivery (CD).

Material and Methods:

Pregnant patients requiring conversion from labor to CD with a pre-existing labor epidural at our institution from 2009 to 2014 were identified. Through a retrospective review, we compared successful epidural conversion with those who required general anesthesia for CD. Patient characteristics were analyzed to identify risk factors for failed epidural conversion for CD.

Results:

A total of 673 patients were included in the study. The rate of epidural conversion failure was 21%. Main risk factors for epidural conversion failure requiring general anesthesia included: younger maternal age (95% CI 0.94, P = 0.0002) and supplementation of intravenous fentanyl (95% CI 0.19, P < 0.0001) or midazolam (95% CI 0.26, P = 0.0008) during CD. A higher risk of conversion failure was also associated with a more urgent CD (CD category 1, 2, and 3 vs category 4).

Conclusion:

Consistent with previous reports, young age and the urgency of CD increases the likelihood of epidural conversion failure. While conversion failure is likely multifactorial and complex, many of these factors are suggestive of inadequate and poorly functioning labor epidurals prior to CD. Prospective studies to further evaluate these factors are necessary, and the best prevention of epidural conversion failure is diligent diagnosis and evaluation of ineffective labor epidural analgesia prior to impending CD.

Impact of anesthesiologist's fellowship status on the risk of general anesthesia for unplanned cesarean delivery

BACKGROUND

Neuraxial analgesia is preferred over general anesthesia for cesarean delivery (CD), particularly in the presence of a labor epidural catheter. We hypothesize that care by a non-obstetric anesthesiologist as compared to care by an obstetric anesthesiologist is associated with a higher risk for use of general anesthesia for CD for patients with a preexisting labor epidural catheter.

METHODS

To determine whether fellowship status of the covering anesthesiologist was a risk factor for general anesthesia, we retrospectively investigated the rate of general anesthesia use in patients with epidural catheters placed for labor analgesia who subsequently required CD. To standardize the practice environment under which these cases occurred, we examined only cases which occurred during coverage by the call team on nights, weekends, and holidays.

RESULTS

There were 1820 cases in which a patient had epidural labor analgesia followed by a CD. Nine hundred and twelve cases were covered by an obstetric anesthesiologist and 908 cases were covered by a non-obstetric anesthesiologist. General anesthesia was used in only 16 of these cases. General anesthesia was more likely to be performed by non-obstetric fellowship trained anesthesiologists (1.54% or 14/908 compared to 0.22% or 2/912; P = 0.002).

CONCLUSIONS

This investigation suggests that the presence of an obstetric fellowship-trained anesthesiologist may be a predictor of decreased rate of general anesthesia use in patients with preexisting indwelling labor epidural catheters.

Labor Epidural Analgesia to Cesarean Section Anesthetic Conversion Failure: A National Survey

Background

If conversion of labor epidural analgesia to cesarean delivery anesthesia fails, the anesthesiologist can be confronted with a challenging clinical dilemma. Optimal management of a failed epidural top up continues to be debated in the absence of best practice guidelines.

Method

All members of the Obstetric Anaesthetists' Association in the United Kingdom were emailed an online survey in May 2017. It obtained information on factors influencing the decision to utilize an existing labor epidural for cesarean section and, if epidural top up resulted in no objective sensory block, bilateral T10 sensory block, or unilateral T6 sensory block, factors influencing the management and selection of anesthetic technique. Differences in management options between respondents were compared using the chi-squared test.

Results

We received 710 survey questionnaires with an overall response rate of 41%. Most respondents (89%) would consider topping up an existing labor epidural for a category-one cesarean section. In evaluating whether or not to top up an existing labor epidural, the factors influencing decision-making were how effective the epidural had been for labor pain (99%), category of cesarean section (73%), and dermatomal level of blockade (61%). In the setting of a failed epidural top up, the most influential factors determining further anesthetic management were the category of cesarean section (92%), dermatomal level of blockade (78%), and the assessment of maternal airway. Spinal anesthesia was commonly preferred if an epidural top up resulted in no objective sensory block (74%), bilateral T10 sensory block (57%), or unilateral T6 sensory block (45%). If the sensory block level was higher or unilateral, then a lower dose of intrathecal local anesthetic was selected and alternative options such as combined-spinal epidural and general anesthesia were increasingly favored.

Discussion

Our survey revealed variations in the clinical management of a failed epidural top up for cesarean delivery, suggesting guidelines to aid decision-making are needed.

Anesthetic management for cesarean delivery in a patient with uncorrected pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries

Pulmonary atresia witha ventricular septal defect and major aortopulmonary collateral arteries is an extremely rare congenital disorder characterized by a high risk of maternal mortality. We present the case of a 24-year-old primigravid woman with uncorrected pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arterieswho presented at 35+5 weeks' gestation. Based on the pathophysiology of the congenital cardiac lesion, cesarean delivery was performed under epidural anesthesia under management by a multidisciplinary team. This report highlights the anesthesia management of a rare uncorrected congenital cardiac lesion for cesarean delivery.

Evaluation of failed and high blocks associated with spinal anesthesia for Cesarean delivery following inadequate labour epidural: a retrospective cohort study

PURPOSE

The purpose of this retrospective cohort study was to investigate factors associated with failed and high spinal blocks in patients who received spinal anesthesia for Cesarean delivery following a labour epidural that was inadequate for surgical anesthesia.

METHODS

We searched our perioperative database for women with a labour epidural who received spinal or combined spinal-epidural anesthesia for Cesarean delivery due to the inadequacy of the existing epidural. The primary outcome was the occurrence of failed spinal blocks, and the secondary outcome was the occurrence of high blocks following spinal administration.

RESULTS

Of the 263 patients in the analysis, there were 29 (11%) failed spinals and nine (3%) high spinals. There was a significant difference between patients with failed spinals and those with successful spinals with regards to receipt of an epidural top-up dose for Cesarean delivery within 30 min of the spinal, type of neuraxial block, body mass index, age, and dose of hyperbaric bupivacaine. In a multivariable analysis, only receipt of an epidural top-up dose was associated with failure (OR, 6.0; 95% CI, 2.1 to 17.0; P < 0.001). As for the risk of a high spinal, patient characteristics and block details were not different amongst patients, except for a younger age in those with a high block.

CONCLUSIONS

Administration of spinal anesthesia within 30 min of an epidural top-up dose is associated with increased risk of failure. We speculate that this may be due in part to the presence of a large volume of local anesthetic in the epidural space, which may be mistaken for cerebrospinal fluid during spinal placement.

Algorithm for the anesthetic management of cesarean delivery in patients with unsatisfactory labor epidural analgesia

The management of a patient presenting with unsatisfactory labor epidural analgesia poses a severe challenge for the anesthetist wanting to provide safe anesthetic care for a cesarean delivery. Early recognition of unsatisfactory labor analgesia allows for replacement of the epidural catheter. The decision to convert labor epidural analgesia to anesthesia for cesarean delivery is based on the urgency of the cesarean delivery, airway examination, and the existence of a residual sensory and motor block.  We suggest an algorithm which is implemented in our department, based on the urgency of the cesarean delivery.

Unilateral hemiparesis with thoracic epidural in an adolescent

Objective. Unilateral sensory and motor blockade is known to occur with epidural anesthesia but is rarely reported in children. The differential diagnosis should include the presence of a midline epidural septum. Case Report. We describe a case of a 16-year-old adolescent who developed repeated complete unilateral extensive epidural sensory and motor blockade with Horner's syndrome after thoracic epidural catheter placement. This unusual presentation of complete hemibody neural blockade has not been reported in the pediatric population. Maneuvers to improve contralateral uniform neural blockade were unsuccessful. An epidurogram was performed to ascertain the correct location of the catheter within the epidural space and presence of sagittal compartmentalization. Conclusion. This case report highlights a less frequently reported reason for unilateral sensory and motor blockade with epidural anesthesia in children. The presence of a midline epidural septum should be considered in the differential diagnosis of unilateral epidural blockade.

Comparison of loss of resistance technique between Epidrum® and conventional method for identifying the epidural space

Background

Epidrum® is a recently developed, air operated, loss of resistance (LOR) device for identifying the epidural space. We investigated the usefulness of Epidrum® by comparing it with the conventional LOR technique for identifying the epidural space.

Methods

One hundred eight American Society of Anesthesiologists (ASA) physical status I or II patients between the ages of 17 and 68 years old and who were scheduled for elective surgery under combined spinal-epidural anesthesia were enrolled in this study. The patients were randomized into two groups: one group received epidural anesthesia by the conventional LOR technique (C group) and the second group received epidural anesthesia using Epidrum® (ED group). While performing epidural anesthesia, the values of variables were recorded, including the number of failures, more than 2 attempts, the incidence of dural puncture, the time needed to locate the epidural space, the distance from the skin to the epidural space and ease of performance, and the satisfaction scores.

Results

The ED group showed a lower failure rate, fewer cases of more than 2 attempts, a lesser time to identify the epidural space, and better ease and satisfaction scores of procedure than the C group, with statistical significance.

Conclusions

Using Epidrum® compared to the conventional LOR technique is an easy, rapid, and reliable method for identifying the epidural space.

Anaesthesia for urgent (grade 1) caesarean section

PURPOSE OF REVIEW

We describe the different possible anaesthetic techniques for an emergency caesarean section. To choose the right method of anaesthesia may have major implications for mother, child and all involved personnel. The major controversy is whether one have other or better alternatives or both than general anaesthesia, with a rapid sequence induction technique, when the foetus is compromised.

RECENT FINDINGS

Recently published studies indicate that a top-up of a well functioning labour epidural is as fast as general anaesthesia, and that the top-up can be performed during preparation and transport. Spinal anaesthesia, when performed by skilled anaesthetists, is as fast or almost as fast as general anaesthesia with a very low failure rate. Combined spinal/epidural may have advantages, especially in high-risk cardiac patients, but is too time-consuming. General anaesthesia still seems to be the method of choice for most anaesthetists in extremely urgent settings. The major disadvantage with general anaesthesia is the risk of failure and the dramatic consequences of a 'cannot intubate, cannot ventilate' situation. Awareness is another concern, and the incidence varies from 0.26 to 1% in recent literature.

SUMMARY

Regional anaesthesia techniques such as a single-shot spinal or a top-up of a well functioning labour epidural analgesia are good alternatives to general anaesthesia in an emergency caesarean setting.

Management of incomplete regional anaesthesia in Germany: results of a nation-wide survey

BACKGROUND

Regional anaesthesia (RA) provides well-defined benefits with known attendant risks. However, incomplete blockade may introduce unanticipated risks depending on the compensatory measures employed. Until now, no data were available characterizing the pattern of response of German anaesthesiologists in this situation. This study analyses interventions in response to incomplete RA in a nation-wide setting.

METHODS

A questionnaire was sent to every German anaesthesia department (n= 1381). Questions focused on interventions coping with an incomplete RA and differentiated between a pre- and a peri-surgical setting and measures to face pain outside the surgical field. If systemic supplementation was administered, we analysed the substances and characterized their influence on subsequent patient care.

RESULTS

Six hundred and sixty-seven questionnaires were returned anonymously, representing a return rate of 48.3%. If RA was incomplete before surgery, 56.8% of anaesthesiologists repeated peripheral blocks, 48.5% repeated epidural (EDA) and 60.4% repeated spinal anaesthesia (SPA). 56.9% of clinicians preferred an early switch to general anesthesia (GA). If RA was incomplete during surgery, 49.5% tended to switch early to GA, 13.9% made attempts to avoid this by intensive systemic supplementation. Benzodiazepines and opioids were the most commonly used substances. Pain or discomfort outside the surgical field was widely managed by intravenous supplementation (67.7%) and only 10.6% were willing to switch to general anaesthesia.

CONCLUSIONS

In Germany, anaesthesiologists manage incomplete RA using a widespread spectrum of measures. Some might introduce specific risks, which potentially outweigh the benefits of RA in comparison to GA techniques.

Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications

Epidural catheter placement offers flexibility in block management. However, during epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, and suboptimal catheter placement can affect the quality of anesthesia. We performed this prospective, randomized, double-blind study to assess the effect of a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle as a priming solution into the epidural space before catheter insertion. We randomized 240 patients into 2 equal groups and measured the quality of anesthesia and the incidence of complications. In the needle group (n = 100), catheters were inserted after injection of a full dose of local anesthetic through the needle. In the catheter group (n = 98), the catheters were inserted immediately after identification of the epidural space. Local anesthetic was then injected via the catheter. We noted the occurrence of paresthesia, inability to advance the catheter, or IV or subarachnoid catheter placement. Sensory and motor block were assessed 20 min after the injection of local anesthetic. Surgery was initiated when adequate sensory loss was confirmed. In the catheter group, the incidence of paresthesia during catheter placement was 31.6% compared with 11% in the needle group (P = 0.00038). IV catheterization occurred in 8.2% versus 2% of patients in the catheter and needle groups, respectively (P = 0.048). More patients in the needle group had excellent surgical conditions than the catheter group (89.6% versus 72.9; P < 0.003). We conclude that giving a single-injection dose via the epidural needle before catheter placement improves the quality of epidural anesthesia and reduces catheter-related complications.

What’s new and novel in obstetric anesthesia? Contributions from the 2003 scientific literature

THE PREGNANT PATIENT: Age; maternal disease; prophylactic antibiotics; gastroesophageal reflux; obesity; starvation; genotyping; coagulopathy; infection; substance abuse; altered drug responses in pregnancy; physiological changes of pregnancy. THE FETUS: Fetal monitoring; intrauterine surgery. THE NEWBORN: Breastfeeding; maternal infection, fever, and neonatal sepsis evaluation. OBSTETRIC COMPLICATIONS: Embolic phenomena; hemorrhage; preeclampsia; preterm delivery. OBSTETRIC MANAGEMENT: External cephalic version and cervical cerclage; elective cesarean delivery; fetal malpresentation; vaginal birth after cesarean delivery; termination of pregnancy. OBSTETRIC ANESTHESIA: Analgesia for labor and delivery; anesthesia for cesarean delivery; anesthesia for short obstetric operations; complications of anesthesia. MISCELLANEOUS: Consent; ethics; history; labor support; websites/books/leaflets/journal announcements.

Failed spinal anesthesia after a psoas compartment block

PURPOSE

To report the case of a patient who experienced failed spinal anesthesia following a psoas compartment block (PCB) and discuss its implications.

CLINICAL FEATURES

A 70-yr-old male was scheduled for a right total hip arthroplasty. He agreed to a PCB for postoperative analgesia and a spinal anesthetic. The spinal anesthetic was performed after completion of the PCB. Free flow of clear fluid was demonstrated at the beginning and at the end of the presumed intrathecal injection. General anesthesia had to be induced because of failure of the spinal anesthetic. The patient awoke from his general anesthetic with a functional PCB and no evidence of residual neuraxial anesthesia. The possibility of epidural spread of local anesthetic from the PCB impairing the ability to perform spinal anesthesia is discussed and reviewed. We hypothesize that local anesthetic in the epidural space may have falsely reassured the anesthesiologist that the needle was properly placed.

CONCLUSION

We describe a case of failed spinal anesthesia following a PCB and discuss its implications.

General anesthesia for cesarean section in a Singapore maternity hospital: a retrospective survey

We conducted a retrospective study of all cases of cesarean section at the KK Women's and Children's Hospital over a one-year period from September 1, 2002 to August 31, 2003, with the aim of evaluating current anesthetic practice. These cases were identified using hospital databases and relevant data was extracted from clinical notes. There were 14244 deliveries during the study period with a cesarean section rate of 25.2% (3583 cases). Of these, 20.4% (732 cases) were performed under general anesthesia. Maternal request was the chief reason for general anesthesia, especially among elective cases. Regional block failure accounted for 16% of the general anesthesia cases performed or 4.0% of the total regional techniques attempted. Regional block failure rate was highest for emergency cases in which an indwelling labor epidural catheter was used to provide surgical anesthesia via a bolus top-up. General anesthesia still has a definite place for cesarean delivery despite the predominant use of regional techniques in our institution.

Incidence and characteristics of failures in obstetric neuraxial analgesia and anesthesia: a retrospective analysis of 19,259 deliveries

A retrospective analysis was performed on 19,259 deliveries that occurred in our institution from January 2000 to December 2002. Anesthesia records and quality assurance data sheets were reviewed for the characteristics and failure rates of neuraxial blocks performed for labor analgesia and anesthesia. The neuraxial labor analgesia rate was 75% and the overall failure rate was 12%. After adequate analgesia from initial placement, 6.8% of patients had subsequent inadequate analgesia during labor that required epidural catheter replacement. Ultimately 98.8% of all patients received adequate analgesia even though 1.5% of patients had multiple replacements. Six percent of epidural catheters had initial intravenous placement but 46% were made functional by simple manipulations without higher subsequent failure. Unintended dural puncture occurred in 1.2% of labor neuraxial analgesia. The incidences of overall failure, intravenous epidural catheter, wet tap, inadequate epidural analgesia and catheter replacement were lower in patients receiving combined spinal-epidural versus epidural analgesia. For cesarean section, 7.1% of pre-existing labor epidural catheters failed and 4.3% of patients required conversion to general anesthesia. Spinal anesthesia for cesarean section had a lower failure rate of 2.7%, with 1.2% of the patients requiring general anesthesia. The overall use of general anesthesia decreased from 8% to 4.3% over the three-year period. Furthermore, regional anesthesia was used in 93.5% of cesarean deliveries with no anesthetic-related mortalities. Future investigations should identify acceptable international standards, risk factors associated with failure and methods to reduce failure before cesarean section.