A prospective randomized trial of lidocaine 30 mg versus 45 mg for epidural test dose for intrathecal injection in the obstetric population

Intrathecal catheter placement after inadvertent dural puncture in the obstetric population: management for labour and operative delivery. Guidelines from the Obstetric Anaesthetists' Association

BACKGROUND

Anaesthetists of all grades who work on a labour ward are likely to be involved in the insertion or management of an intrathecal catheter after inadvertent dural puncture at some point in their careers. Although the use of intrathecal catheters after inadvertent dural puncture in labour has increased in popularity over recent decades, robust evidence on best practice has been lacking.

METHODS

The Obstetric Anaesthetists' Association set up an expert working party to review the literature. A modified Delphi approach was used to produce statements and recommendations on insertion and management of intrathecal catheters for labour and operative delivery following inadvertent dural puncture during attempted labour epidural insertion. Statements and recommendations were graded according to the US Preventive Services Task Force grading methodology.

RESULTS

A total of 296 articles were identified in the initial literature search. Further screening identified 111 full text papers of relevance. A structured narrative review was produced which covered insertion of an intrathecal catheter; initial dosing; maintenance of labour analgesia; topping-up for operative delivery; safety features; complications; and recommended follow-up. The working party agreed on 17 statements and 26 recommendations. These were generally assigned a low or moderate level of certainty. The safety of mother and baby were a key priority in producing these guidelines.

CONCLUSIONS

With careful management, intrathecal catheters can provide excellent labour analgesia and may also be topped-up to provide anaesthesia for caesarean or operative vaginal delivery. The use of intrathecal catheters, however, also carries the risk of significant drug errors which may result in high- or total-spinal anaesthesia, or even cardiorespiratory arrest. It is vital that all labour wards have clear guidelines on the use of these catheters, and that staff are educated as to their potential complications.

Using part of the initial analgesic dose as the epidural test dose did not delay the onset of labor analgesia: a randomized controlled clinical trial

BACKGROUND

Epidural test dose for labor analgesia is controversial and varies widely in clinical practice. It is currently unclear whether using a portion of the initial dose for analgesia as the test dose delays the onset time of analgesia, compared to the traditional test dose.

METHODS

One hundred and twenty-six parturients who chose epidural analgesia during labor were randomly assigned to two groups. The first dose in group L was 3 ml 1.5% lidocaine, and in the RF group was 10 ml 0.1% ropivacaine combined with 2 μg/ml fentanyl. After 3 min of observation, both groups received 8 ml 0.1% ropivacaine combined with 2 μg/ml fentanyl. The onset time of analgesia, motor and sensory blockade level, numerical pain rating scale, patient satisfaction score, and side effects were recorded.

RESULTS

The onset time of analgesia in group RF was similar to that in group L (group RF vs group L, 7.0 [5.0-9.0] minutes vs 8.0 [5.0-11.0] minutes, p = 0.197). The incidence of foot numbness (group RF vs group L, 34.9% vs 57.1%, p = 0.020) and foot warming (group RF vs group L, 15.9% vs 47.6%, p < 0.001) in group RF was significantly lower than that in group L. There was no difference between the two groups on other outcomes.

CONCLUSIONS

Compared with 1.5% lidocaine 3 ml, 0.1% ropivacaine 10 ml combined with 2 μg/ml fentanyl as an epidural test dose did not delay the onset of labor analgesia, and the side effects were slightly reduced.

CLINICAL TRIAL REGISTRATION

http://www.chictr.org.cn (ChiCTR2100043071).

ED90 of epidural esketamine with 0.075% ropivacaine for labor analgesia in nulliparous parturients: a prospective, randomized and dose-finding study

Background: Because it has been reported that racemic ketamine had a local anesthetic-sparing effect when used for epidural analgesia this would suggest the likelihood of a potential advantage (less pruritus) over opioid drugs. Esketamine has greater analgesic efficacy than racemic ketamine, but the optimum dosage regimen for epidural use is undetermined. The aim of this study was to determine the ED₉₀ of epidural esketamine when coadministered with 0.075% ropivacaine for labor analgesia. Methods: A total of 65 laboring nulliparous patients were enrolled in this study from 16 March 2022 to 15 October 2022. The patients were randomly assigned to receive 0, 0.25, 0.5, 0.75 or 1.0 mg/mL esketamine with 0.075% ropivacaine epidurally. An effective response to the epidural loading dose was defined as numerical rating scale pain score ≤3 at 30 min after the end of the epidural loading dose (10 mL of the ropivacaine 0.075% solution with the added esketamine). The ED₉₀ of epidural esketamine coadministered with 0.075% ropivacaine with 95% confidence intervals for labor analgesia was determined using probit regression. Secondary outcomes and side effects were recorded. Results: The estimated value of ED₉₀ with 95% CIs for epidural esketamine with 0.075% ropivacaine was 0.983 (0.704-2.468) mg/mL. The characteristics of sensory and motor block, consumption of ropivacaine per hour, duration of first or second stage, Apgar scores did not differ among the five groups. The incidence of mild dizziness in Group esketamine 1.0 mg/mL was significantly higher than that in other groups (p < 0.05). No statistical differences were found in other side effects among groups. Conclusion: The ED₉₀ value of epidural esketamine coadministered with 0.075% ropivacaine for labor analgesia in nulliparous parturients was about 1.0 mg/mL. Furthermore, our results suggested that epidural esketamine would cause dose-dependent mild dizziness especially at doses up to 1.0 mg/mL. As a single epidural additive, esketamine may not be suitable for labor analgesia. Future studies may investigate the appropriate dosage of esketamine at slightly higher concentrations of local anesthetics or larger initial volume of analgesia, or explore other potential advantages of esketamine. Clinical Trial Registration: (https://www.chictr.org.cn/bin/project/edit?pid=159764), identifier (ChiCTR2200057662).

A Prospective Randomized Trial of Ropivacaine 5 mg with Sufentanil 2.5 μg as a Test Dose for Detecting Epidural and Intrathecal Injection in Obstetric Patients

Objectives: Traditional epidural test dose is somewhat unsuited in obstetrics because of potential risk of severe adverse effects when it is accidentally injected into the subarachnoid space. Some hospitals use a proportion of the total dose of epidural labor analgesia as a test dose. The aim of our study was to assess the effectiveness and safety of ropivacaine 5 mg with sufentanil 2.5 μg to detect intrathecal injection. Methods: This prospective randomized study enrolled parturients who had the demand for epidural labor analgesia and randomly divided them into two groups. Then, 5 mL of 0.1% ropivacaine with sufentanil 2.5 μg was injected into the epidural space or the subarachnoid space in the epidural (EP) group and the intrathecal (IT) group, respectively. The ability to detect intrathecal injection and side effects were assessed to work out the effectiveness and safety. Results: For spinal injection, the sensitivity and the specificity of the symptoms of either warmth or numbness or both assessed at 3 min were both 100%, and the observed negative predictive value (NPV) and positive predictive value (PPV) were 100%. All parturients in the IT group and 2.33% of parturients in the EP group had sensory blockade to cold or pinprick (p < 0.0001). A total of 77.55% (38 of 49) of parturients in the IT group were found to have a motor block. A 10 min assessment showed the median cephalad cold and pin levels were T8 and T10, respectively, and the median Bromage score was 4 in the IT group. Incidences of adverse effects in both groups were low. Conclusions: Ropivacaine 5 mg with sufentanil 2.5 μg is effective and safe to detect intrathecal injection as an epidural test dose in obstetric patients.

Neuraxial labor analgesia: Initiation techniques

The ideal technique for labor analgesia would have a quick onset, predictable quality, and adjustable depth and duration. Moreover, it would be easy to perform and have minimal maternal and fetal side effects. A catheter-based neuraxial approach encompasses these desirable characteristics and includes the epidural, combined spinal epidural, dural puncture epidural, and intrathecal catheter techniques. In this review, we outline the unique technical considerations, analgesic characteristics, and side effect profiles for each technique that can ultimately impact the maternal-fetal dyad. The selection of neuraxial analgesia techniques should consider the patient and team's goals and expectations, the clinical context, and the institutional culture. Labor analgesic techniques that initiate with an intentional dural puncture component have a faster onset, greater bilateral and sacral spread, and lower rates of epidural catheter failure. Further elucidation of the mechanisms, benefits, and risks of each neuraxial initiation technique will continue to benefit patients and care providers.

Accidental Dural Puncture Management: 10-Year Experience at an Academic Tertiary Care Center

BACKGROUND AND OBJECTIVES

The use of spinal catheters for extended periods after accidental dural puncture (ADP) and administration of intrathecal saline via spinal catheters have been advocated to decrease the incidence of postdural puncture headache and the subsequent need for epidural blood patch (EBP), with mixed results observed.

METHODS

We reviewed the medical records of 218 patients with ADP who either had the epidural resited or had a spinal catheter (with or without the administration of intrathecal saline). We compared the incidence of headache and the need for blood patch between these groups. We also assessed complications when a standard lidocaine epidural test dose was administered intrathecally and compared this with complications when a solution normally used for labor combined spinal epidurals was administered.

RESULTS

There was no difference in the incidence of postdural puncture headache between the resited epidural group and the spinal catheter group, 68.0% versus 55.9% (odds ratio [OR], 1.7; 95% confidence interval [95% CI], 1.0-2.9; P = 0.07). Resiting the epidural catheter was associated with a significant increase in the number of EBPs when compared with using a spinal catheter, 52.0% versus 20.3% (OR, 4.2; 95% CI, 2.4-7.6; P < 0.001) and when compared with spinal catheters with intrathecal saline, 52.0% versus 8.1% (OR, 12.3; 95% CI, 4.3-35.4; P < 0.001). There was a significant difference in the number of blood patches between normal body mass index patients and morbidly obese patients, 55.2% versus 25.0% (OR, 3.7; 95% CI, 1.2-11.2; P = 0.02). Complications (hypotension prompting pressors, high spinal, and emergency cesarean delivery because of nonreassuring fetal status) occurred more frequently when a lidocaine test dose was immediately administered after ADP versus administering a labor combined spinal epidural solution.

CONCLUSIONS

Insertion of spinal catheters after ADP and administration of intrathecal normal saline via spinal catheters reduce the need for EBP compared with resiting the epidural. Administration of the standard epidural test dose intrathecally is associated with frequent and significant complications.

Drug Residues after Intravenous Anesthesia and Intrathecal Lidocaine Hydrochloride Euthanasia in Horses

Background

Intrathecal lidocaine hydrochloride under general anesthesia has been used as an alternative method of euthanasia in equids. Carnivore, scavenger, and even human consumption of horse meat from carcasses have been anecdotally reported in rural areas after this method of euthanasia. The presence of drug residues in horse meat has not been investigated.

Hypothesis/Objectives

To investigate if drug residues are found in horse tissues and determine their concentrations.

Animals

Of 11 horses requiring euthanasia for medical reasons.

Methods

Prospective descriptive study. Horses were anesthetized with total IV dose of xylazine (mean, 2.5 mg/kg), midazolam (0.1 mg/kg), and ketamine hydrochloride (mean, 5.8 mg/kg). An atlanto‐occipital cisterna centesis for the collection of cerebrospinal fluid (CSF) and administration of lidocaine hydrochloride (4 mg/kg) was performed. Blood samples for both serum and plasma, skeletal muscle (triceps brachii, gluteus medius), and CSF were collected for the determination of drug residues. Frozen skeletal muscle available from 5 additional horses that received standard dosages of drugs for short‐term anesthesia (xylazine 1.1 mg/kg, midazolam 0.1 mg/kg, and ketamine 2.2 mg/kg) also were analyzed.

Results

Drug residues were found in the tissues of all horses, but at extremely low concentrations.

Conclusions and Clinical Importance

Euthanasia by administration of lidocaine intrathecally to horses under IV anesthesia poses a low risk of toxicity to carnivores and scavengers that might consume muscle tissue from a carcass in which this protocol has been used.

Programmed intermittent epidural bolus versus continuous epidural infusion for pain relief during termination of pregnancy: a prospective, double-blind, randomized trial

BACKGROUND

Pain is a major concern during medical abortion but no evidence-based recommendations for optimal analgesia during medical termination of pregnancy are available. We compared two methods of epidural analgesia during second trimester termination of pregnancy, with the primary aim of assessing the incidence of motor block.

METHODS

Women were randomly assigned to receive continuous epidural infusion (CEI Group; n=52) or programmed intermittent epidural bolus (PIEB Group; n=52). Assessment of motor block was performed every hour. Patients with a modified Bromage score <6 were considered to have motor block.

RESULTS

Motor block occurred more frequently in the CEI Group compared with the PIEB Group (46.2% vs. 5.8%, P<0.001). Pain scores were low and comparable between groups. Patients in the CEI Group experienced nausea more frequently than those in the PIEB Group (34.6% vs. 13.5%, P=0.022). The degree of satisfaction was higher in the PIEB Group compared with the CEI Group.

CONCLUSIONS

During second trimester termination of pregnancy in our patient groups, a programmed intermittent epidural bolus technique was associated with less motor block and greater patient satisfaction than continuous epidural infusion. Both techniques had similar analgesic efficacy.

Electrophysiologic Study of a Method of Euthanasia Using Intrathecal Lidocaine Hydrochloride Administered during Intravenous Anesthesia in Horses

Background

An intravenous (IV) overdose of pentobarbital sodium is the most commonly used method of euthanasia in veterinary medicine. However, this compound is not available in many countries or rural areas resulting in usage of alternative methods such as intrathecal lidocaine administration after IV anesthesia. Its safety and efficacy as a method of euthanasia have not been investigated in the horse.

Hypothesis/Objectives

To investigate changes in mean arterial blood pressure and electrical activity of the cerebral cortex, brainstem, and heart during intrathecal administration of lidocaine. Our hypothesis was that intrathecal lidocaine affects the cerebral cortex and brainstem before affecting cardiovascular function.

Animals

Eleven horses requiring euthanasia for medical reasons.

Methods

Prospective observational study. Horses were anesthetized with xylazine, midazolam, and ketamine; and instrumented for recording of electroencephalogram (EEG), electrooculogram (EOG), brainstem auditory evoked response (BAER), and electrocardiogram (ECG). Physical and neurological (brainstem reflexes) variables were monitored. Mean arterial blood pressure was recorded throughout the study.

Results

Loss of cerebro‐cortical electrical activity occurred up to 226 seconds after the end of the infusion of lidocaine solution. Cessation of brainstem function as evidenced by a lack of brainstem reflexes and disappearance of BAER occurred subsequently. Undetectable heart sounds, nonpalpable arterial pulse, and extremely low mean arterial blood pressure supported cardiac death; a recordable ECG was the last variable to disappear after the infusion (300–1,279 seconds).

Conclusions and Clinical Importance

Intrathecal administration of lidocaine is an effective alternative method of euthanasia in anesthetized horses, during which brain death occurs before cardiac death.

[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.