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

Anesthesia complications in the birthplace: is the neuraxial block always to blame?

This article highlights the common and some of the very serious complications that may occur following neuraxial analgesia for labor and delivery, including headache, backache, infection, hypotension, and hematoma. Total spinal and failed block also are discussed, as are complications unique to epidural anesthesia, such as the intravascular injection of large volumes of local anesthetic (causing seizure or cardiac arrest) and accidental dural puncture.

Postpartum seizures after epidural analgesia: a patient with a mutation of the factor V Leiden and prothrombin gene

We report the case of a 27-year-old parturient who developed a headache within 12 hours of delivery and who subsequently seized. Further examination, including magnetic resonance imaging and computed tomographic scan, showed a partial thrombosis of a transversal venous sinus, the underlying cause being an activated protein C resistance caused by a heterozygote factor V Leiden mutation and heterozygote prothrombin-gene mutation G20210A. Seven months after delivery, the patient is in good health, showing no neurocognitive disability.

The Episure™ Syringe: A Novel Loss of Resistance Syringe for Locating the Epidural Space

INTRODUCTION

The Episure syringe is a unique spring-loaded loss-of-resistance (LOR) syringe with a coaxial compression spring within a Portex Pulsator LOR syringe. This syringe supplies a constant pressure while the operator is advancing the Tuohy needle.

METHODS

We evaluated the syringe using an artificial model of the ligamentum flavum, an anesthetized pig, and women who desired epidural analgesia for labor.

RESULTS

The operator, using the spring-loaded syringe, was able to stop the forward movement of the needle, so that compared with a standard LOR syringe less of the needle protruded out the back of the laboratory model. Satisfactory labor analgesia in the human study and radiograph analyses in the porcine model confirmed epidural placement in all attempts.

CONCLUSION

The spring-loaded syringe is a potentially useful LOR syringe that provides a reliable, objective end-point for identification of the epidural space.

Complete failure of spinal anaesthesia in obstetrics

Intrathecal anaesthesia, either as a single shot-spinal or as part of a combined spinal-epidural technique, is now widely accepted as the management of choice for caesarean section. It generally produces rapid and predictable anaesthesia, yet occasionally fails for no apparent reason. Four case reports of seemingly inexplicable complete failure of intrathecal anaesthesia are presented, together with a literature review of other cases and possible causes of the failure, which include anatomical abnormality, drug failure and management failure.

Detection of Intravascular Epidural Catheter Placement: A Review

Intravascular placement of an epidural catheter is recognised as a potentially fatal complication of epidural anaesthesia and analgesia. Up to 10% of epidural catheters may be inserted into an epidural vessel, the majority of which will be recognised; however, a proportion (1% of all epidural catheters inserted) may not be identified as lying intravascularly. Opinions differ on the optimal method for identifying intravascular catheters and no perfect method exists. Some debate the need for a test of correct location, as a lack of specificity may mean that a proportion of correctly located catheters are withdrawn and resited. This review outlines the incidence and risk factors associated with intravascular placement and aims to evaluate the detection methods that have been described, in an attempt to answer the question: “What is the optimal way of detecting intravascular placement of an epidural catheter?”

Maternal and neonatal outcome after cesarean section: the impact of anesthesia

BACKGROUND

Among the anesthetic technologies used, regional anesthesia is becoming the most common in cesarean section (CS) deliveries. Aim. This retrospective survey examined the variables taken into account when selecting the anesthetic technique to be used, and how this choice affects the outcome for the mother and the newborn.

METHODS

One thousand eight hundred and seventy elective and emergency CS were evaluated for anesthetic technique used, indications, and maternal and neonatal outcome.

RESULTS

Of the 611 elective CS (32.6%), 206 (33.8%) were performed under general anesthesia and 405 (66.2%) under regional anesthesia. Of the 1259 emergency CS performed (67.4%), 525 (41.9%) were under general anesthesia and 734 (58.1%) under regional anesthesia. Conditions associated with a newborn 1-minute Apgar score of <7 were general anesthesia and multiple pregnancy (p<0.01); a 5-minute Apgar score of <7 was only associated with multiple pregnancy. The most important factor for very low Apgar scores was the presence of fetal malformations. Whatever the chosen technique, neither maternal deaths directly or indirectly due to the anesthesia nor major maternal and perinatal complications were found.

CONCLUSIONS

This survey confirms the preference for regional anesthesia during elective cesarean sections and for general anesthesia in emergency situations. Moreover, newborn outcome was found not to be influenced either by the technique used or by the character of the procedure.

Pharmacology of drugs formulated with DepoFoam: a sustained release drug delivery system for parenteral administration using multivesicular liposome technology

Lamellar liposome technology has been used for several decades to produce sustained-release drug formulations for parenteral administration. Multivesicular liposomes are structurally distinct from lamellar liposomes and consist of an aggregation of hundreds of water-filled polyhedral compartments separated by bi-layered lipid septa. The unique architecture of multivesicular liposomes allows encapsulating drug with greater efficiency, provides robust structural stability and ensures reliable, steady and prolonged drug release. The favourable characteristics of multivesicular liposomes have resulted in many drug formulations exploiting this technology, which is proprietary and referred to as DepoFoam. Currently, two formulations using multivesicular liposome technology are approved by the US FDA for clinical use, and many more formulations are at an experimental developmental stage. The first clinically available formulation contains the antineoplastic agent cytarabine (DepoCyt) for its intrathecal injection in the treatment of malignant lymphomatous meningitis. Intrathecal injection of DepoCyt reliably results in the sustained release of cytarabine and produces cytotoxic concentrations in cerebrospinal fluid (CSF) that are maintained for at least 2 weeks. Early efficacy data suggest that DepoCyt is fairly well tolerated, and its use allows reduced dosing frequency from twice a week to once every other week and may improve the outcome compared with frequent intrathecal injections of unencapsulated cytarabine. The second available formulation contains morphine (DepoDur) for its single epidural injection in the treatment of postoperative pain. While animal studies confirm that epidural injection of DepoDur results in the sustained release of morphine into CSF, the CSF pharmacokinetics have not been determined in humans. Clinical studies suggest that the use of DepoDur decreases the amount of systemically administered analgesics needed for adequate postoperative pain control. It may also provide superior pain control during the first 1-2 postoperative days compared with epidural administration of unencapsulated morphine or intravenous administration of an opioid. However, at this timepoint the overall clinical utility of DepoDur has yet to be defined and some safety concerns remain because of the unknown CSF pharmacokinetics of DepoDur in humans. The versatility of multivesicular liposome technology is reflected by the many agents including small inorganic and organic molecules and macromolecules including proteins that have successfully been encapsulated. Data concerning many experimental formulations containing antineoplastic, antibacterial and antiviral agents underscore the sustained, steady and reliable release of these compounds from multivesicular liposomes after injection by the intrathecal, subcutaneous, intramuscular, intraperitoneal and intraocular routes. Contingent on the specific formulation and manufacturing process, agents were released over a period of hours to weeks as reflected by a 2- to 400-fold increase in elimination half life. Published data further suggest that the encapsulation process preserves bioactivity of agents as delicate as proteins and supports the view that examined multivesicular liposomes were non-toxic at studied doses. The task ahead will be to examine whether the beneficial structural and pharmacokinetic properties of multivesicular liposome formulations will translate into improved clinical outcomes, either because of decreased drug toxicity or increased drug efficacy.

The Epidural Test Dose: A Review

This review systematically examines the literature on the ability of the classical epidural test dose and other strategies to detect intravascular, intrathecal, or subdural epidural needle/catheter misplacement. For detection of simulated intravascular misplacements, a sensitivity (S) and a positive predictive value (PPV) > or =80 demonstrated by at least two randomized controlled trials coming from two different centers were determined for the following tests and patient populations: Nonpregnant adult patients = increase in systolic blood pressure (SBP) > or =15 mm Hg (S = 80-100 and 93-100; PPV = 80-100 and 83-100) or either an increase in SBP > or =15 mm Hg or an increase in heart rate > or =10 bpm after the injection of 10 (S = 100; PPV = 83-100) or 15 microg of epinephrine (S = 100; PPV = 83-100); pregnant patients = sedation, drowsiness, or dizziness within 5 min after the injection of 100 microg of fentanyl (S = 92-100; PPV = 91-95); and children = increase in SBP > or =15 mm Hg after the injection of 0.5 microg/kg of epinephrine (S = 81-100; PPV = 100). Conversely, more studies are required to determine the best strategies to detect intrathecal and subdural epidural needle/catheter misplacements in these three patient populations.

Combined spinal-epidural anaesthesia

PURPOSE OF REVIEW

The purpose of this review is to present the most important recent studies on the clinical use of the combined spinal-epidural technique.

RECENT FINDINGS

The predominant recent literature on the combined spinal-epidural technique involves its use in obstetrics. A 2004 UK survey showed that the use of the technique is increasing. Studies are presented which show the role of intrathecal drug selection for improving the quality of the combined spinal-epidural technique for anaesthesia for Caesarean section. The pros and cons of using the method as opposed to traditional epidural for labour analgesia are still being debated; the results of a meta-analysis show that combined spinal-epidural provides faster onset of analgesia and increased maternal satisfaction but the incidence of pruritus is high. This review also looks at some technical aspects of the technique.

SUMMARY

The use of combined spinal-epidural is widespread and increasing particularly in obstetric anaesthesia and analgesia. Recent literature provides new information about the choice of drugs and technical aspects of the technique and also about its advantages and drawbacks in obstetric and non-obstetric patients.