Pre-puncture ultrasound guided epidural insertion before vaginal delivery

Efficacy and safety of ultrasound-guided versus landmark-guided neuraxial puncture: a systematic review, network meta-analysis and trial sequential analysis of randomized clinical trials

BACKGROUND

Data suggest that preprocedural ultrasound may improve the efficacy of central neuraxial puncture. However, it remains uncertain whether these findings can be extended to various clinical scenarios, including diverse patient populations and the application of real-time ultrasound guidance. Additionally, it is unclear whether ultrasound-guided techniques improve safety and patient-centered outcomes.

METHODS

We searched six databases for randomized trials of adult patients undergoing neuraxial puncture, comparing real-time ultrasound, preprocedural ultrasound, and landmark palpation for efficacy, safety and patient-centered outcomes. Our primary outcome was a failed first-attempt neuraxial puncture. After two-person screening and data extraction, meta-analyses were conducted and the Grading of Recommendations Assessment, Development and Evaluation approach was applied to assess the certainty of evidence.

RESULTS

Analysis of 71 studies involving 7153 patients, both real-time ultrasound (OR 0.30; 95% credible interval (CrI) 0.15 to 0.58; low certainty) and preprocedural ultrasound (OR 0.33; 95% CrI 0.24 to 0.44; moderate certainty) showed a significant reduction in the risk of a failed first neuraxial puncture. Real-time ultrasound had the best performance for preventing first-attempt failures (low certainty evidence). Although real-time ultrasound was also the leading method for reducing the risk of complete neuraxial puncture failure, the results did not show a statistically significant difference when compared with landmark palpation. Preprocedural ultrasound, however, significantly reduced the odds of complete puncture failure (OR 0.29; 95% CrI 0.11 to 0.61). These ultrasound-guided approaches also contributed to a reduction in certain complications and increased patient satisfaction without any other significant differences in additional outcomes. Trial sequential analysis confirmed that sufficient information was achieved for our primary outcome.

CONCLUSIONS

Ultrasound-guided neuraxial puncture improves efficacy, reduces puncture attempts and needle redirections, reduces complication risks, and increases patient satisfaction, with low to moderate certainty of evidence. Despite real-time ultrasound's high ranking, a clear superiority over preprocedural ultrasound is not established. These results could prompt anesthesiologists and other clinicians to reassess their neuraxial puncture techniques.

Comparative efficacy of ultrasound guidance or conventional anatomical landmarks for neuraxial puncture in adult patients: a systematic review and network meta-analysis

BACKGROUND

Preprocedural, real-time, and computer-aided three-dimensional ultrasound has been widely used for neuraxial puncture; however, the optimal guidance is unclear. We examined the comparative efficacy of three ultrasound guidance and anatomical landmarks for neuraxial puncture in adults.

METHODS

We searched for randomised controlled studies comparing the efficacy of ultrasound guidance and anatomical landmarks for neuraxial puncture in adults using electronic databases and unpublished studies. The primary outcomes were first-pass success and patient satisfaction. A random-effects network meta-analysis (NMA) was used.

RESULTS

We identified 74 eligible studies (7090 patients). Preprocedural ultrasound and real-time ultrasound-guided neuraxial puncture improved first-pass success compared with anatomical landmarks (risk ratio [RR] 1.6; 95% credible interval [CrI] 1.3-1.9; RR 1.9; 95% CrI 1.3-2.9, respectively, moderate confidence). Computer-aided ultrasound-guided neuraxial puncture also increased first-pass success (RR 1.8; 95% CrI 0.97-3.3, low confidence), although estimates were imprecise. However, real-time ultrasound-guided neuraxial puncture resulted in minimal difference in first-pass success compared with preprocedural ultrasound (RR 1.2; 95% CrI 0.8-1.8, moderate confidence). Preprocedural ultrasound improved patient satisfaction slightly compared with anatomical landmark use (standardised mean differences 0.28; 95% CrI 0.092-0.47, low confidence).

CONCLUSIONS

This NMA provides evidence supporting ultrasound-guided neuraxial puncture compared with use of anatomical landmarks, including indirect comparisons. Among the three ultrasound guidance methods, preprocedural ultrasound appears to be a better adjunctive option.

Comparison of ultrasound-guided and traditional localisation in intraspinal anesthesia: a systematic review and network meta-analysis

OBJECTIVES

The optimal puncture technique for neuraxial anaesthesia in different populations is unclear. We sought to obtain data from randomised controlled trials comparing the impact of ultrasound-guided technology and traditional positioning technology on the success rate of neuraxial anaesthesia.

DESIGN

Systematic review and network meta-analysis using study populations, interventions, intervention comparisons, outcome measures and study types.

DATA SOURCES

PubMed, Embase, Cochrane Library and Web of science were searched until 31 September 2022.

ELIGIBILITY CRITERIA

We included randomised controlled trials comparing three types of neuraxial anaesthesia: ultrasound-assisted, ultrasound real-time guidance and conventional positioning to describe which neuraxial anaesthesia modality is best for patients and to recommend the appropriate one for different populations.

DATA EXTRACTION AND SYNTHESIS

Five independent reviewers retrieved, screened and edited included studies using standardised methods. Assess risk of bias using the Cochrane Collaboration and Evidence Project tools. Network meta-analysis was performed using STATA V.15 statistical software.

RESULTS

Twenty-two studies containing three different interventions were included. The SUCRA values of first-pass success rates for the three neuraxial anaesthesia methods were real-time guidance (82.8%), ultrasound-assisted (67.1%) and traditional positioning (0.1%). Both ultrasound techniques improved first-pass success rates compared with traditional localization, but there was no significant difference between the two. Subgroup analysis showed that the use of real-time ultrasound guidance for neuraxial anaesthesia in pregnant and patients with obesity improved first-pass success rates. Ultrasound-assisted technology can improve first-attempt success rates in older patients with abnormal lumbar spine anatomy.

CONCLUSION

Compared with conventional positioning, ultrasound guidance technology can improve the first-pass success rate of neuraxial anaesthesia, but there is no significant difference between ultrasound-assisted and real-time guidance technology. The results of subgroup analysis tell us that the most suitable neuraxial anaesthesia method is different for different groups of people.

PROSPERO REGISTRATION NUMBER

PROSPERO number: CRD42022376041.

Usage of augmented reality for interventional neuraxial procedures: A phantom-based study

BACKGROUND

Neuraxial access is necessary for an array of procedures in anaesthesia, interventional pain medicine and neurosurgery. The commonly used anatomical landmark technique is challenging and requires practical experience.

OBJECTIVE

We aimed to evaluate the technical feasibility of an augmented reality-guided approach for neuraxial access and tested the hypothesis that its use would improve success as the primary outcome. As secondary outcomes, we measured accuracy and the procedural duration compared with the classical landmark approach.

DESIGN

A randomised phantom-based study.

SETTING

The three-dimensional image of a thoracolumbar phantom spine model with the surrounding soft tissue was created with a neurosurgical planning workstation and ideal trajectories to the epidural space on the levels T10-L1 were planned using a paramedian approach. Both the three-dimensional holographic image of the spine and the trajectories were transferred to an augmented reality-headset. Four probands (two anaesthesiologists, one neuroradiologist and one stereotactic neurosurgeon) performed 20 attempts, 10 each of either conventional landmark or augmented reality-guided epidural punctures, where anatomical level, side and sequence of modality were all randomised.

OUTCOME MEASURES

Accuracy was assessed by measuring Euclidean distance and lateral deviation from the predefined target point. Success of epidural puncture on the first attempt was compared between the conventional and the augmented reality-guided approaches.

RESULTS

Success was achieved in 82.5% of the attempts using augmented reality technique, compared with 40% with the conventional approach [ P  = 0.0002, odds ratio (OR) for success: 7.07]. Euclidean distance (6.1 vs. 12 mm, P  < 0.0001) and lateral deviation (3.7 vs. 9.2 mm, P  < 0.0001) were significantly smaller using augmented reality. Augmented reality-guided puncture was significantly faster than with the conventional landmark approach (52.5 vs. 67.5 s, P  = 0.0015).

CONCLUSION

Augmented reality guidance significantly improved the accuracy and success in an experimental phantom model of epidural puncture. With further technical development, augmented reality guidance might prove helpful in anatomically challenging neuraxial procedures.

Pre-Procedural Lumbar Neuraxial Ultrasound-A Systematic Review of Randomized Controlled Trials and Meta-Analysis

A pre-procedural ultrasound of the lumbar spine is frequently used to facilitate neuraxial procedures. The aim of this review is to examine the evidence sustaining the utilization of pre-procedural neuraxial ultrasound compared to conventional methods. We perform a systematic review of randomized controlled trials with meta-analyses. We search the electronic databases Medline, Cochrane Central, Science Direct and Scopus up to 1 June 2019. We include trials comparing a pre-procedural lumbar spine ultrasound to a non-ultrasound-assisted method. The primary endpoints are technical failure rate, first-attempt success rate, number of needle redirections and procedure time. We retrieve 32 trials (3439 patients) comparing pre-procedural lumbar ultrasounds to palpations for neuraxial procedures in various clinical settings. Pre-procedural ultrasounds decrease the overall risk of technical failure (Risk Ratio (RR) 0.69 (99% CI, 0.43 to 1.10), p = 0.04) but not in obese and difficult spinal patients (RR 0.53, p = 0.06) and increase the first-attempt success rate (RR 1.5 (99% CI, 1.22 to 1.86), p < 0.0001, NNT = 5). In difficult spines and obese patients, the RR is 1.84 (99% CI, 1.44 to 2.3; p < 0.0001, NNT = 3). The number of needle redirections is lower with pre-procedural ultrasounds (SMD = −0.55 (99% CI, −0.81 to −0.29), p < 0.0001), as is the case in difficult spines and obese patients (SMD = −0.85 (99% CI, −1.08 to −0.61), p < 0.0001). No differences are observed in procedural times. Ιn conclusion, a pre-procedural ultrasound provides significant benefit in terms of technical failure, number of needle redirections and first attempt-success rate. Τhe effect of pre-procedural ultrasound scanning of the lumbar spine is more significant in a subgroup analysis of difficult spines and obese patients.

European Society of Anaesthesiology and Intensive Care Guidelines on peri-operative use of ultrasound for regional anaesthesia (PERSEUS regional anesthesia): Peripheral nerves blocks and neuraxial anaesthesia

Nowadays, ultrasound-guidance is commonly used in regional anaesthesia (USGRA) and to locate the spinal anatomy in neuraxial analgesia. The aim of this second guideline on the PERi-operative uSE of UltraSound (PERSEUS-RA) is to provide evidence as to which areas of regional anaesthesia the use of ultrasound guidance should be considered a gold standard or beneficial to the patient. The PERSEUS Taskforce members were asked to define relevant outcomes and rank the relative importance of outcomes following the GRADE process. Whenever the literature was not able to provide enough evidence, we decided to use the RAND method with a modified Delphi process. Whenever compared with alternative techniques, the use of USGRA is considered well tolerated and effective for some nerve blocks but there are certain areas, such as truncal blocks, where a lack of robust data precludes useful comparison. The new frontiers for further research are represented by the application of USG during epidural analgesia or spinal anaesthesia as, in these cases, the evidence for the value of the use of ultrasound is limited to the preprocedure identification of the anatomy, providing the operator with a better idea of the depth and angle of the epidural or spinal space. USGRA can be considered an essential part of the curriculum of the anaesthesiologist with a defined training and certification path. Our recommendations will require considerable changes to some training programmes, and it will be necessary for these to be phased in before compliance becomes mandatory.

Efficacy of ultrasound guidance for lumbar punctures: a systematic review and meta-analysis of randomised controlled trials

Ultrasound guidance has been reported to facilitate the performance of lumbar punctures (LPs). However, the use of ultrasound guidance has not yet received consistent conclusions. We performed a systematic review and meta-analysis to determine the efficacy of ultrasound-guided LPs. PubMed, Embase and the Cochrane Library were searched for randomised controlled trials comparing ultrasound guidance with traditional palpation for LPs in adults. The primary outcome was risk of failed procedures. A random-effects Mantel-Haenzsel model or random-effects inverse variance model was used to calculate relative risks (RRs) or standardised mean differences (SMDs) with 95% CIs. Twenty-eight trials (N=2813) met the inclusion criteria. Ultrasound-guided LPs were associated with a reduced risk of failed procedures (RR=0.58, 95% CI 0.39 to 0.85, p=0.005). No significant heterogeneity was detected (I2=27%) among these trials. It further decreased first attempt to failure (RR=0.43, 95% CI 0.30 to 0.62, p<0.00001), mean attempts to success (SMD=-0.61, 95% CI -0.80 to -0.43, p=0.00001) and incidences of complications of headache and backache (RR=0.63, 95% CI 0.46 to 0.85, p=0.003). Ultrasound guidance is an effective technique for LPs in adults.

Ultrasonography for lumbar neuraxial block

Ultrasonography can be useful to perform a lumbar neuraxial block. It aids in understanding the anatomy of the lumbar spine before the procedure. Pre-procedural ultrasound imaging provides information about the accurate intervertebral level for puncture, optimal needle insertion point, and depth of needle advancement for a successful neuraxial block. The key ultrasonographic views for lumbar neuraxial block include the transverse midline interlaminar and parasagittal oblique views. Ultrasonography can facilitate lumbar neuraxial block in difficult cases, such as the elderly, obese patients, and patients with anatomical abnormality of the lumbar spine. This review elucidates the basics of spinal ultrasonography for lumbar neuraxial block and the current evidence regarding ultrasound-guided neuraxial block in adults.

Conventional landmark palpation vs. preprocedural ultrasound for neuraxial analgesia and anaesthesia in obstetrics - a systematic review and meta-analysis with trial sequential analyses

The aim of this systematic review and meta-analysis was to examine the efficacy, time taken and the safety of neuraxial blockade performed for obstetric patients with the assistance of preprocedural ultrasound, in comparison with the landmark palpation method. The bibliographic databases Central, CINAHL, EMBASE, Global Health, MEDLINE, Scopus and Web of Science were searched from inception to 13 February 2020 for randomised controlled trials that included pregnant women having neuraxial procedures with preprocedural ultrasound as the intervention and conventional landmark palpation as the comparator. For continuous and dichotomous outcomes, respectively, we calculated the mean difference using the inverse-variance method and the risk ratio with the Mantel-Haenszel method. In all, 22 trials with 2462 patients were included. Confirmed by trial sequential analysis, preprocedural ultrasound increased the first-pass success rate by a risk ratio (95%CI) of 1.46 (1.16-1.82), p = 0.001 in 13 trials with 1253 patients. No evidence of a difference was found in the total time taken between preprocedural ultrasound and landmark palpation, with a mean difference (95%CI) of 50.1 (-13.7 to 113.94) s, p = 0.12 in eight trials with 709 patients. The quality of evidence was graded as low and very low, respectively, for these co-primary outcomes. Sub-group analysis underlined the increased benefit of preprocedural ultrasound for those in whom the neuraxial procedure was predicted to be difficult. Complications, including postpartum back pain and headache, were decreased with preprocedural ultrasound. The adoption of preprocedural ultrasound for neuraxial procedures in obstetrics is recommended and, in the opinion of the authors, should be considered as a standard of care, in view of its potential to increase efficacy and reduce complications without significant prolongation of the total time required.

Ultrasound-Guided Neuraxial Anesthesia

PURPOSE OF REVIEW

There has been a recent surge of interest in clinical applications of ultrasound, which has revolutionized acute pain management. This review is to summarize the current status of ultrasound utilization in neuraxial anesthesia, the most common type of regional anesthesia.

RECENT FINDINGS

Ultrasound-assisted and ultrasound-guided neuraxial anesthesia has improved clinical accuracy and patient safety through landmark identification including proper vertebral level and midline, as well as via measurements on neuraxial space. Direct needle or catheter visualization during the entire procedure has not yet been achieved consistently. The recent introduction of ultrasound into neural anesthesia has clinical performance benefits and patient safety implications, with documented improvement on overall efficacy with higher first attempt success rate as well as less needle pass. More controlled studies are needed for the overall impact of ultrasonography in neuraxial anesthesia in obstetric and non-obstetric patients.

Could preprocedural ultrasound increase the first-pass success rate of neuraxial anesthesia in obstetrics? A systematic review and meta-analysis of randomized controlled trials

Neuraxial anesthesia is a common practice in obstetrics. Evidence suggests that preprocedural ultrasound versus the conventional landmark location method accurately identifies a given intervertebral space and predicts the needle insertion depth required to reach the spinal canal. However, whether the preprocedural ultrasound examination improves the first-pass success (FPS) rate remains elusive. Major databases were systematically searched for all relevant studies published in English up to June 2019. Eighteen randomized controlled trials including 1844 patients were enrolled. The quality of eligible studies was assessed, and predefined outcomes were synthesized by meta-analysis. The primary results showed that preprocedural ultrasound increased the FPS rate in patients with predicted puncture difficulty but not in patients who were easily punctured. Preprocedural ultrasound reduced the number of redirections and punctures and decreased the incidence of vascular puncture and backache. There was no evidence of a reduction in failed punctures. We also noted that preprocedural ultrasound prolonged the identification time but not the procedure time. Thus, this systematic review provides evidence that preprocedural ultrasound does not improve the FPS rate of neuraxial anesthesia in patients who are easily palpated, although it increases the FPS rate in patients who are difficult to palpate.

Preprocedural ultrasound as an adjunct to blind conventional technique for epidural neuraxial blockade in patients undergoing hip or knee joint replacement surgery: A randomised controlled trial

BACKGROUND AND AIMS

The patients undergoing total knee and hip replacement surgeries are mostly obese, more than 50 years of age with osteophytic spine and spine deformities making the blind conventional technique of regional anaesthesia more difficult. The aim of the study was to compare the role of preprocedural ultrasound scan to conventional blind technique in obese patients with osteophytic spines undergoing total knee or hip replacement surgeries in terms of technical difficulty, clinical efficacy, safety and patient comfort.

METHODS

A prospective, randomised controlled trial was conducted in which 210 consenting American Society of Anesthesiologists (ASA) grade III patients, age >50 years, Body Mass Index (BMI) ≥30 kg/m2 with osteophytic spines including abnormalities undergoing joint replacement surgeries were randomised in two groups. Ultrasound group ("B") received Combined Spinal Epidural Anaesthesia (CSEA) after preprocedural lumbar ultrasound scan. In control group ("A"), CSEA was given by blind conventional technique. The primary objective was to compare the rate of successful epidural block on 1st needle insertion attempts in both the groups. The secondary objectives were to compare both groups in terms of ease, success, comfort and safety of epidural block.

RESULTS

Ultrasound improved success of CSEA at 1st attempt from 74.3% in control group ("A") to 85.7% in Ultrasound group ("B") (P = 0.038). Fewer needle insertion attempts, passes and anaesthesiologist were required in ultrasound group. Pearson correlation coefficient was 0.976 using both views.

CONCLUSION

Preprocedural ultrasound scan is a useful adjunct to lumbar epidural blocks in obese patients with osteophytic abnormal spines.

Recommendations on the Use of Ultrasound Guidance for Adult Lumbar Puncture: A Position Statement of the Society of Hospital Medicine

When ultrasound equipment is available, along with providers who are appropriately trained to use it, we recommend that ultrasound guidance should be used for site selection of lumbar puncture to reduce the number of needle insertion attempts and needle redirections and increase the overall procedure success rates, especially in patients who are obese or have difficult-to-palpate landmarks. We recommend that ultrasound should be used to more accurately identify the lumbar spine level than physical examination in both obese and nonobese patients. We suggest using ultrasound for selecting and marking a needle insertion site just before performing lumbar puncture in either a lateral decubitus or sitting position. The patient should remain in the same position after marking the needle insertion site. We recommend that a low-frequency transducer, preferably a curvilinear array transducer, should be used to evaluate the lumbar spine and mark a needle insertion site. A high-frequency linear array transducer may be used in nonobese patients. We recommend that ultrasound should be used to map the lumbar spine, starting at the level of the sacrum and sliding the transducer cephalad, sequentially identifying the lumbar spine interspaces. We recommend that ultrasound should be used in a transverse plane to mark the midline of the lumbar spine and in a longitudinal plane to mark the interspinous spaces. The intersection of these two lines marks the needle insertion site. We recommend that ultrasound should be used during a preprocedural evaluation to measure the distance from the skin surface to the ligamentum flavum from a longitudinal paramedian view to estimate the needle insertion depth and ensure that a spinal needle of adequate length is used. We recommend that novices should undergo simulation-based training, where available, before attempting ultrasound-guided lumbar puncture on actual patients. We recommend that training in ultrasound-guided lumbar puncture should be adapted based on prior ultrasound experience, as learning curves will vary. We recommend that novice providers should be supervised when performing ultrasound-guided lumbar puncture before performing the procedure independently on patients.

Point-of-Care Ultrasound in Established Settings

The original and most widely accepted applications for point-of-care ultrasound (POCUS) are in the settings of trauma, shock, and bedside procedures. Trauma was the original setting for the introduction of POCUS and has been standardized under the four-plus view examination called the Focused Assessment with Sonography in Trauma (FAST). This examination was found to be especially practice changing for achieving rapid diagnoses in critically ill patients who are too unstable for the delays and transportation inherent in more advanced imaging with computed tomography. This application was broadened from the critically ill trauma patient to any critically ill patient, particularly the patient in undifferentiated shock. Although the Focused Assessment with Sonography in Trauma examination originally focused on sources of hemorrhage causing hypovolemic shock, POCUS also can quickly differentiate cardiogenic, obstructive, and distributive shock and help identify the more specific etiology such as massive pulmonary emboli, pericardial tamponade, and pneumothoraces. By expediting diagnosis, POCUS facilitates faster definitive treatment of life-threatening conditions. In pursuing treatment, US continues to serve a role in the form of visually guiding many procedures that were previously done blindly. US guidance of procedures has improved the safety of central line insertion, thoracentesis, and paracentesis, and has an emerging role in lumbar puncture. Experience in bedside US is becoming a vital tool in the clinician's bedside assessment and management, filling a void between the stethoscope and the more advanced studies and interventions available through radiology. Understanding the strengths and limitations of US enables clinicians to identify the appropriate situations in which they can apply this tool confidently.

Lumbar Ultrasonography for Obstetric Neuraxial Blocks: Sonoanatomy and Literature Review

Ultrasonography has gained popularity in recent years among anaesthesiologists and being used widely for regional blocks and central venous catheterization. Ultrasonography for neuraxial blocks was found beneficial especially for determining the correct needle insertion site and estimating the needle insertion depth of epidural space. In many recent studies, ultrasound guided epidural and spinal blocks have been evaluated among obstetric patients. Pre-procedural lumbar ultrasonography and real time ultrasound guidance for neuraxial blocks was the subject of these studies. We aimed to evaluate lumbar ultrasonography for obstetric neuraxial blocks. We describe the principles of lumbar ultrasound scanning techniques and present a practical review of lumbar sonoanatomy. We discuss the potential impact and benefits of the ultrasound-guided technique in improving obstetric neuraxial blocks and limitations of its use in clinical practice, based on previous studies.

Observational Study Using Ultrasound to Assess Midline Labor Epidural Analgesia Placement and Analgesic Efficacy

OBJECTIVES

Labor epidural analgesia failure may relate to nonmidline placement of epidural catheters. We hypothesized that greater deviations of the epidural catheter insertion point from the ultrasound (US)-determined midline would be associated with less effective labor analgesia.

METHODS

A prospective ethically approved cohort study was conducted. Fifty-two healthy average-sized women receiving labor epidural analgesia, inserted by the landmark technique, were approached after delivery. Immediately after removing the epidural catheter, we determined the epidural space midline using US and compared it to the epidural catheter insertion point and to the patient-identified midline (assessed by a pinprick in 1-mm increments). Correlations between the US midline-to-catheter insertion point distance and additional epidural local anesthetic requirements (primary outcome), pain verbal numeric rating scale scores (0-10) 1 hour after epidural insertion, and maternal satisfaction with analgesia were determined. The differences in distances were assessed by a Bland-Altman analysis.

RESULTS

There were no significant correlations between the US midline-to-epidural catheter insertion point distance and additional epidural local anesthetic requirements (R²  = 0.138; P = .33), pain verbal numeric rating scale scores 1 hour after the epidural (R²  = 0.121; P = .40) or maternal satisfaction (R²  = 0.085; P = .57). The Bland-Altman analysis revealed that the mean ± SD US midline-to-epidural catheter insertion point distance and patient-identified midline distances were 0.38 ± 0.31 and 0.35 ± 0.46 cm, respectively.

CONCLUSIONS

In our laboring population, the hypothesis that nonmidline epidural insertion is associated with less-effective labor analgesia was not confirmed in this study cohort. We found minimal differences in distances between the US midline to epidural catheter insertion point and US midline to patient-identified midline.

Central neuraxial analgesia for labor: an update of the literature

Numerous techniques are in use to provide analgesia for labor, of which central neuraxial block is widely considered superior to non-neuraxial options. Central neuraxial techniques have evolved over many years to provide greater efficacy, safety and maternal satisfaction. This narrative review focuses on the literature relating to central neuraxial labor analgesia from the past 5 years, from November 2010 to October 2015. We discuss the evidence related to the various central neuraxial techniques used, the increasingly widespread use of ultrasound guidance and the evidence surrounding other novel methods of central neuraxial block insertion. The timing of institution of central neuraxial analgesia in labor is considered, as are the advances in maintenance regimens for labor analgesia.

Does Preprocedural Ultrasound Increase the First-Pass Success Rate of Epidural Catheterization Before Cesarean Delivery? A Randomized Controlled Trial

BACKGROUND

Preprocedural ultrasound may improve the efficacy and safety of epidural catheterization, especially in difficult cases. Most studies of ultrasound-assisted epidural catheterization in the obstetric population are dated and nonblinded with inconsistent designs. This double-blind, randomized controlled study aimed to compare the ultrasound-assisted with the conventional palpation techniques for epidural catheterization in parturients undergoing cesarean delivery. We hypothesized that the use of preprocedural ultrasound would increase the success rate of epidural catheterization at the first needle pass.

METHODS

Eligible subjects were American Society of Anesthesiologists physical status II parturients with full-term singleton pregnancy undergoing elective cesarean delivery using double-interspace combined spinal-epidural anesthesia. Exclusion criteria were age <19 or >40 years, body mass index ≥35 kg/m, women presenting in labor or having any contraindication to neuraxial anesthesia, marked spinal deformity, previous spinal surgery, or impalpable anatomical landmarks. One hundred ten patients were randomly allocated into 2 equal groups (palpation and ultrasound groups). All procedures were performed by a single experienced anesthesiologist. Patients and investigators assessing the outcome data were blinded to group allocation. A systematic spinal ultrasound assessment and a sham procedure were performed in the ultrasound and palpation groups, respectively, before attempting epidural catheterization. The primary outcome was the rate of successful epidural catheterization at the first needle pass. Secondary outcomes were the rate of successful epidural catheterization at the first skin puncture, number of performed needle passes and skin punctures, duration of the epidural procedure, patient satisfaction from the procedure, and complications of the procedure (incidence of unintentional dural and vascular punctures, failed block, unilateral or patchy block, and backache).

RESULTS

Data from 108 patients (55 patients in the palpation group and 53 patients in the ultrasound group) were analyzed. The rate of successful epidural catheterization at the first needle pass was 60% in the palpation group and 58.5% in the ultrasound group (95% confidence interval of the difference in proportions between groups is -18.5% to 21.6%; P > 0.99). There were no significant differences between the 2 groups in the success rate at the first skin puncture, the number of needle passes and skin punctures, or patient satisfaction. The median (range) duration of the epidural procedure was 185 (57-680) seconds in the ultrasound group and 215 (114-720) seconds in the palpation group (P = 0.036 with the Mann-Whitney U test and P = 0.083 with the Student t test with unequal variances). The overall rate of complications of the procedure was low in both groups.

CONCLUSIONS

For experienced anesthesiologists, it remains unclear whether preprocedural ultrasound improves the epidural catheterization technique in parturients with palpable anatomical landmarks undergoing cesarean delivery.

Journal of Clinical Monitoring and Computing 2015 end of year summary: anesthesia

Clinical monitoring is an essential part of the profession of anesthesiology. It would therefore be impossible to review all articles published in the Journal of Clinical Monitoring and Computing that are relevant to anesthesia. Because other reviews will address monitoring of the respiratory and cardiovascular system, the current review will limit itself to topics uniquely related to anesthesia. The topics are organized according to the chronological order in which an anesthetic proceeds: secure the airway; ventilate and deliver anesthetic gases; monitor vital organ function and anesthetic depth; and ensure analgesia during/after emergence from anesthesia (locoregional anesthesia and pain control).