Factors associated with difficult neuraxial blockade

Training and assessment of skills in neuraxial access-Protocol of a scoping review

BACKGROUND

Access to the neuraxial space, including lumbar punctures and neuraxial anaesthesia, is an everyday procedure in clinical practice. Traditionally these procedures rely on manual palpation technique, but ultrasound is a useful tool when patients prove challenging. Presently, there is a lack of evidence-based guidelines for technical skills acquisition, both with and without ultrasound, and likewise, competency assessment approaches vary globally. Accordingly, we aim to assess the current evidence regarding learning and assessment in neuraxial access± $$ \pm $$ ultrasound, for future educational recommendations.

METHODS

This scoping review will be conducted in accordance with the Preferred Reporting Items for Systematic and Meta-Analysis (PRISMA) statement, together with the PRISMA Extension for Scoping Reviews. A systematic search strategy will be based on a PICO approach, focusing on physicians, medical students, or nurses being exposed to education, training, or assessment in procedural neuraxial access± $$ \pm $$ ultrasound. No comparators are obligated, but outcomes should be assessable using the Kirkpatrick four levels of training evaluation. The search will be performed in Cochrane Library, Embase, Medline, Scopus, PubMed, and CINAHL. Independently, two authors will screen the studies and conflicts will be resolved by a third author. Relevant predefined data will be extracted and analysed using a descriptive approach. The quality of the studies will be assessed using the Medical Education Research Study Quality Instrument.

DISCUSSION

This scoping review will contribute by presenting gathered evidence of an overview of the different approaches to achieving education and training of technical skills in neuraxial access, and how skills are tested, which could guide research and future recommendations for skills development and assessment.

Predicting clinical entry point for thoracic epidural catheter insertion during paramedian approach: A prospective observational study

Background and Aims

Thoracic epidural insertion has high failure rates in the mid-thoracic region due to steep angulation of oblique bending of spinous processes. The preferred skin puncture point for epidural needle insertion in the paramedian sagittal plane with respect to the superior/inferior tip of spinous process or inter-spinous cleft in the mid-thoracic region (T5-8) is not standard. The primary objective of this prospective observational study was to find the skin puncture point which had the best success rate for a successful epidural catheterization. Secondary objectives were to study the number of attempts and passes required to locate epidural space, incidence of failed epidural, and its relationship with patient characteristics and demographics.

Material and Methods

After informed consent, 155 patients planned for general anesthesia with epidural analgesia in the mid-thoracic region were included in the trial. Patient demographics, the details of epidural attempts with respect to anatomical landmarks, distance from the midline, and number of passes in each attempt were noted. Epidural catheterization was considered successful after demonstrating dermatomal band of sensory blockade.

Results

The success rate at different skin puncture sites was not statistically significant (P = 0.58). We found a failure rate of 12.9%. Failed epidural catheterization was significantly high in the age group >56 years (n = 62 and P = 0.007).

Conclusion

In our study, none of the skin puncture points had a significant association with successful epidural insertion in mid-thoracic segments using a para-median approach.

Changes in needle maneuver space and optimal insertion site for midline neuraxial puncture with progressive age: an analysis in computed tomography scans

INTRODUCTION

We systematically describe the morphology and accessibility of interspinous spaces across age groups of patients. Our primary goal was to objectively estimate if the maneuver space for a virtual spinal needle changes with age. Our secondary goal was to estimate if the optimal site and angle for midline neuraxial puncture change with age.

METHODS

Measurements were performed in mid-sagittal CT images. The CT images were retrospectively collected from the database of the Department of Radiology of our hospital. Three age groups were studied: 21-30 years (n=36, abbreviated Y(oung)), 51-60 years (n=43, abbreviated M(iddle-aged)) and older than 80 years (n=46, abbreviated Old).A needle trajectory is defined by the chosen puncture point and by the angle at which the needle is directed to its target. We define a Spinal Accessibility Index (SAI) by numerically integrating for an interspace all possible combinations of puncture points and angles that lead to a successful virtual puncture. Successful in this context means that the needle tip reaches the spinal or epidural space without bone contact. Reproducible calculation of the SAI was performed with the help of custom-made software. The larger the value of the SAI, the more possible successful needle trajectories exist that the practitioner may choose from.The optimal puncture point and optimal angle in an age group at a certain level of the spine are defined by the combination of these two, which generates the highest success rate of the entire sample of this age group.

RESULTS

At all levels of the spine, the median SAI differed significantly between age groups (independent-samples Kruskal-Wallis test, p<0.001-0.047). The SAI consistently decreased with increasing age. Post-hoc analyses using pairwise comparisons showed a significantly higher SAI in group Y versus Old at all levels (p<0.001-0.006) except at level thoracic (Th)1-Th2 (p=0.138). The SAI was significantly higher in group M versus Old at all levels (p<0.001-0.028) except at level Th1-Th2 (p=0.061), Th4-Th5 (p=0.083), Th9-Th10 (p=1.00) and Th10-Th11 (p=1.00).

CONCLUSIONS

Needle maneuver space in midline neuraxial puncture significantly decreases with progressive age at all levels of the spine. Optimal puncture points and angles are similar between age groups.

Ultrasound predictors of difficult spinal anesthesia: a prospective single-blind observational study

BACKGROUND

Ultrasound showed to improve the precision and efficacy of spinal anesthesia (SA) through the identification of specific structures surrounding the intrathecal space, such as the anterior and posterior complex of dura mater (DM). The aim of this study was to verify the efficacy of ultrasonography in predicting difficult SA trough the analysis of different ultrasound patterns.

METHODS

This prospective single-blind observational study involved 100 patients undergoing orthopedic or urological surgery. A first operator chose by landmarks the intervertebral space where he wanted to perform SA. Then a second operator recorded the visibility of DM complexes at ultrasound. Subsequently, the first operator, blinded to the ultrasound evaluation, performed SA, defined as "difficult" in case of failure, change of intervertebral space, operator exchange, duration >400 seconds or more than 10 needle passes.

RESULTS

The ultrasound visualization of only posterior complex or the failure in visualization of both complexes showed a positive predictive value of 76% and 100%, respectively, towards difficult SA vs. 6% when both complexes were visible; P<0.001. A negative correlation was found between the number of visible complexes and both patients' age and BMI. Landmark-guided evaluation underestimated the intervertebral level in 30% of cases.

CONCLUSIONS

Ultrasound showed a high accuracy in detecting difficult spinal anesthesia and its use should be recommended in the daily clinical practice in order to increase success rate and minimize patient discomfort. The absence of both DM complexes at ultrasound should lead the anesthetist to evaluate other intervertebral levels or consider alternative techniques.

The impact of pregnancy on women with adolescent idiopathic scoliosis: a scoping review

INTRODUCTION

Adolescent idiopathic scoliosis is the most common spinal deformity encountered in adolescents and larger curves are more prevalent in girls. For females with scoliosis, women's health issues are of particular concern, especially pregnancy. The aim of this review was to summarise the best available evidence to determine the influence of pregnancy on scoliosis-related outcomes in women with scoliosis and whether scoliosis affects maternal-health outcomes, differentiating between patients who have been managed conservatively and/or surgically.

EVIDENCE ACQUISITION

A search was conducted using CINAHL, Scopus, Cochrane Database, MEDLINE, and EMBASE from inception to May 2023 to identify relevant articles in any language. The scoping review followed the PRISMA-ScR guidelines. Studies were eligible if they included pregnant women (primiparous or multiparous) with a diagnosis of scoliosis of unknown aetiology. The results were summarized by outcomes, including pregnancy and scoliosis-related outcomes and type of management.

EVIDENCE SYNTHESIS

Our comprehensive search strategy identified 6872 articles, of which 50 articles were eligible for this review. Back pain appears to be more prevalent in this population during pregnancy and associated with the major curve and the decrease of lumbar lordosis. There have been reports of failed attempted spinal anaesthesia among patients with instrumented scoliosis correction and minor complications related to epidural anaesthesia at a higher rate compared to non-instrumented patients and healthy controls, however successful spinal analgesia can be achieved in patients with instrumented scoliosis correction. Overall, the caesarean section rate was similar in scoliosis patients compared to controls without scoliosis and to national averages. Curve progression occurs in some but not all patients during pregnancy, and this phenomenon occurs irrespective of the treatment received.

CONCLUSIONS

Higher-quality prospective longitudinal research is needed to understand the relationship between pregnancy and adolescent idiopathic scoliosis. Further, the patient's perspective, concerns and fears surrounding pregnancy with scoliosis are yet to be explored. Exploring the impact of pregnancy on women with adolescent idiopathic scoliosis would have clinically relevant outcomes and could help provide pertinent answers to patients and healthcare workers and help guide future research.

Anticipated vs. Experienced Pain at Site of Spinal Needle Insertion in Patients Undergoing Elective Lower Segment Caesarean Section: Perspective from Resource-Limited Region

Background

Despite significant advantages, approximately 20% of pregnant patients refuse spinal anaesthesia in caesarean section due to fear of spinal needle prick. Studies have shown that the patient's expectation of pain is higher than what they experience in real. The objective was to evaluate the difference between anticipated and actually experienced pain at the spinal needle insertion site in spinal anaesthesia for pregnant women undergoing elective lower segment caesarean section (ELSCS).

Method

The cross-sectional study was conducted in a labour room suite of a tertiary care hospital.

Results

A total of 50 patients scheduled for ELSCS were included. The median experienced pain at the site of spinal needle insertion was significantly low as compared to anticipated pain (P value < 0.01). For the identification of predictors impacting the anticipated and experienced pain, univariate and multivariate regression models were applied. Amsterdam Preoperative Anxiety and Information Scale ≥11 for anticipated pain showed a statistically significant positive correlation in univariate (coefficient: 2.59; 95% CI: 1.49 to 3.68; P value < 0.001) and multivariable analyses (coefficient: 2.51; 95% CI: 1.36 to 3.67; P value < 0.001). Thus, anxiety was associated with statistically significant higher anticipated pain.

Conclusion

In conclusion, there is a remarkable difference in the obstetric population between anticipated and actually experienced pain at the site of spinal needle insertion in ELSCS.

A comprehensive, bed-side scoring system to predict difficult lumbar puncture

Background and Aims

Spinal anesthesia (SA) is the most widely practiced neuraxial anesthesia. Lumbar puncture (LP) at multiple levels and multiple attempts due to any reason may cause discomfort and even serious complications. Hence the study was conducted to evaluate the patient variables that can predict difficult LP thus allowing for the use of alternate techniques.

Material and Methods

We included 200 patients of ASA physical status I-II, scheduled to undergo elective infra-umbilical surgical procedures under spinal anesthesia. During preanesthetic evaluation, difficulty score was assessed using the 5 variables: Age, abdominal circumference, spinal deformity - assessed as axial trunk rotation (ATR) value, anatomical spine assessed by spinous process landmark grading system (SLGS) and patient position, by assigning a score of 0- 3 for each variable, with a total score of 0 - 15. The difficulty of LP was graded as easy, moderate or difficult based on total number of attempts and spinal levels by independent experienced investigator. The scores obtained during preanesthetic evaluation and the data collected after performing LP were analyzed using multivariate analysis and P value noted.

Results

Our study showed that above patient variables correlated well with difficult LP scoring (P < 0.001). SLGS was noted to be a strong predictor, while ATR value a weak predictor. The correlation between the total score and grades of SA had a positive association (R = 0.6832, P < 0.00001) and was statistically significant. A median difficulty score of 2, 5 and 8 predicted easy, moderate and difficult LP respectively.

Conclusion

The scoring system provides for a useful tool to predict difficult LP and helps both patient and anesthesiologist to choose an alternative technique.

Predictors of Failed Spinal Arachnoid Puncture Procedures: An Artificial Neural Network Analysis

Background Knowing the predicting factors for difficult neuraxial blocks might help better plan the procedure. This study aimed to determine the predictors of failed spinal arachnoid puncture procedures using artificial neural network (ANN) analysis. Methodology With approvals, prospectively collected data from 300 spinal arachnoid punctures in the operation theater of an academic institute having postgraduate anesthesia training were retrospectively evaluated. Fifteen variables from anthropo-demographic, spinal surface anatomy, procedure, and performers' experiences were fed as input for the ANN. A failed spinal arachnoid puncture procedure was defined as the requirement of more than three punctures, with three punctures but more than six passes, or if the performer handed over the procedure to another, considering it difficult after the second puncture. STATCRAFT v.2 software (Predictive Analytics Solutions Pvt. Ltd., Bengaluru, India) was used for ANN model generation. Considering the overfitting tendency of the ANN, Pr(>|z|) < 0.01 in the ANN was considered significant. The area under the receiver operating characteristic (AuROC) curve of the ANN model and its sensitivity and specificity were also assessed. Significant factors with multiple gradings were also evaluated for their statistical significance across the grades or classes using INSTAT software (Graphpad Prism, La Jolla, CA, USA); a two-tailed P-value of <0.05 was considered significant. Results Interspinous process-based spine grade, performers' experience, and positioning difficulty were significant determinants of failed spinal arachnoid puncture procedures in the ANN model. The ANN model had an AuROC of 0.907, specificity of 0.976, and sensitivity of 0.385. The interclass comparison showed that increasing spinal grades and decreasing experiences were associated with increased pass and puncture. Conclusions The ANN model found the determinants of the failed spinal arachnoid puncture procedure well with good AuROC and specificity but poor sensitivity.

White Cane Approach to Teaching Spinal Anesthesia

With aging-associated obesity and osteoarthritis, anesthesiology trainees and their instructors face difficulties in identifying the surface anatomy and landmarks for spinal anesthesia, and successfully advancing the needle into the intrathecal space. Through a series of illustrations and instructions, this teaching tool suggests that using a spinal needle in the same way that a blind person uses a white cane may improve a trainee's ability to successfully perform a lumbar puncture. Reviewing the technique and instructions with the trainee before approaching the patient can minimize verbal instructions in the patient's presence and may lead to improved efficiency and trainee success.

Type, management, and associated factors of failed spinal anesthesia in cesarean section. Prospective cohort study

Background

Spinal anesthesia is an anesthesia technique suitable for cesarean section to avoid respiratory complications. However, the management of spinal anesthesia is very important because spinal anesthesia may fail and the patient may be exposed to pain and discomfort.

Objective

To assess the type, management, and related factors of failure of spinal anesthesia at cesarean section.

Methods

Multicenter prospective cohort study was conducted at a public hospital in Addis Ababa on 794 mothers who met the criteria for cesarean section under spinal anesthesia. Data collection methods were adopted, including chart reviews and observations of spinal anesthesia procedures. The data collected was entered in Epi info version 7 and analyzed in SPSS version 20. Independent variables with dependent variables were analyzed using logistic regression. A p-value of 0.05 for & it; was considered a statistically significant test cutoff.

Result

Of 121 failed spinal anesthesia 35 were complete and 86 were partial failed spinal anesthesia from those complete failed spinal anesthesia were managed by repeating spinal and converting to general anesthesia and partial failed spinal anesthesia were managed by the supplementary drug. Experience of the anesthetist <1 (AOR = 4.12, 95% CI, 2.47-6.90), patient position (AOR = 14.43,95%CL, 2.65-78.61), number of attempts>1 (AOR = 9.26, 95% CI, 5.69-15.01), bloody CSF (AOR = 6.37, 95%CI, 2.90-13.96), BMI ≥30kgm2 (AOR = 2.03, 95%CI, 1.12-3.68) and dose of bupivacaine <10 mg (AOR = 2.72, 95% CI, 1.33-5.53) were found to be statistically significant associated with failed spinal anesthesia.

Conclusion and recommendation

Experience of anesthetists (<1 year), obesity, bupivacaine dose <10 mg, bloody appearance of CSF, number of attempts> 1 were associated factors for failed spinal anesthesia in cesarean section. Our failed spinal management is not the same among hospitals and does not follow recommended failed spinal management. Up-skilling of anesthesia professionals should be considered on identified associated factors of failed spinal anesthesia and management of failed spinal anesthesia should be based on the recommended guidelines.

A Comparison of Two Peripheral Nerve Blocks Combined With General Anesthesia in Elderly Patients Undergoing Arthroplasty for Hip Fractures: A Pilot Randomized Controlled Trial

Background

Combined anesthesia can be a promising option for hip surgery when neuraxial anesthesia is contraindicated. Lumbar and sacral plexus blocks, and femoral nerve and lateral femoral cutaneous (LFC) nerve blocks in combination with general anesthesia (GA) are commonly used in elderly patients undergoing arthroplasty for hip fracture surgery. However, no study has compared these two anesthetic strategies in the perioperative period.

Methods

A total of 41 elderly patients scheduled for arthroplasty for hip fracture surgery were randomized into group A (n = 20) and group B (n = 21). Group A received femoral nerve block, LFC nerve blocks, and GA, and group B received lumbar plexus block, sacral plexus block, and GA. Primary outcomes were incidences of hemodynamic events and changes in blood pressure (BP) and heart rate (HR). Secondary outcomes included time and drug consumption, infusion and bleeding volume, eyes opening time after surgery, and postoperative quality recovery rate.

Results

Compared with group B, group A showed a lower incidence of intraoperative hypotension (p < 0.001), higher BP [including mean arterial pressure (MAP), systolic BP (SBP), and diastolic BP (DBP)] following induction (IN), and higher HR from mid-surgery. Time required for nerve blockade (p < 0.001) and ephedrine consumption was significantly shorter in group A (p < 0.001), while sufentanil consumption was higher as compared to group B (p = 0.002). No significant differences in other intraoperative parameters and postoperative quality recovery rate were reported during the observation.

Conclusion

Our pilot data indicate that compared with lumbar and sacral plexus blocks, femoral nerve and LFC nerve blocks may provide more stable intraoperative hemodynamics and a comparable postoperative recovery for elderly patients undergoing arthroplasty for hip fracture under GA. Further studies with a larger sample size are needed to derive stronger evidence.

Factors predicting difficult spinal block: A single centre study

Background and Aims:

Several factors determine the success of dural puncture. We aimed to assess the association of first puncture success and number of attempts with characteristics of the patient, provider, technique and equipment.

Material and Methods:

This prospective, observational study was performed in 1647 adult patients undergoing surgery under spinal anesthesia. Patient characteristics, anatomical landmarks, spinal bony deformity, provider experience, technique, skin punctures, needle redirections, subarachnoid space depth, and complications, if any, were noted. Difficult dural puncture was assessed by first puncture success and number of attempts (skin punctures plus needle redirections) required for successful needle placement.

Results:

First puncture success was obtained in 872 (52.9%) patients. Failed dural puncture occurred in 4 (0.2%) of 1647 patients. Multivariate logistic regression analysis revealed that longer distance from C7 vertebral spine to tip of coccyx (P = 0.04), lower subarachnoid space depth (P = 0.001), good quality of bony landmarks (P = 0.001) and absence of crowded spine (P = 0.02) were associated with first puncture success. Male gender, poor or no spinal landmarks, presence of bony deformity and lower level of provider's experience predicted increased number of attempts for successful dural puncture.

Conclusion:

First puncture success of spinal block was influenced only by patient's anatomical factors, whereas the number of attempts required for successful block were predicted by both provider and patient factors.

Optimal angle of needle insertion for spinal anesthesia in patients with spondylolisthesis: an ultrasonographic study

Background

Spondylolisthesis is a common degenerative spinal deformity. At the level of spondylolisthesis, the anatomy of the interlaminar space may differ from normal spine, in which case optimal angle of the needle insertion for spinal anesthesia may change. This study compared the optimal angle of needle insertion during spinal anesthesia in patients with and without lumbar spondylolisthesis using ultrasound.

Methods

We recruited 40 patients, 20 with and 20 without lumbar spondylolisthesis (group S and N, respectively). Ultrasonography was performed in the transverse midline and parasagittal oblique views at the spondylolisthesis level and the adjacent upper level. We measured the probe application angle with the longest interlaminar height of the ligamentum flavum-dura mater complex (LFD), depth from the skin to the LFD, depth from the skin to the anterior complex, and intrathecal space width. A positive angle represented a cephalad angulation.

Results

The optimal needle insertion angle in the transverse midline view at the spondylolisthesis level was (-) 2.7 ± 3.4° in group S and 0.8 ± 2.5° in group N (P\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$<$$\end{document}< 0.001). In the parasagittal oblique view, it was (-) 2.7 ± 4.5° in group S and 1.0 ± 3.2° in group N (P = 0.004). There were no between-group differences in the angles at the upper level, with all cephalad angles in both views. Other ultrasound image data were comparable between groups.

Conclusion

In patients with spondylolisthesis, caudad angulation of the spinal needle can aid successful spinal puncture at spondylolisthesis level, both in the midline and paramedian approaches.

Trial registration

www.ClinicalTrials.gov (NCT04426916); registered 11 June 2020.

Alternative Technique for Difficult Epidural Needle Placement: A Case Report

A central neuraxial block may be difficult to perform in elderly patients with lumbar spine deformities, calcified ligaments, and narrowing of the epidural space. We report a case of difficult epidural needle placement in an elderly patient scheduled for bilateral total knee replacement (TKR). We attempted epidural needle placement many times without success. However, when a modified technique was used, the epidural space was identified easily and confirmed, the epidural catheter was inserted and fixed, and the postoperative epidural analgesia was effective.

Comparison of three sitting positions for combined spinal - epidural anesthesia: a multicenter randomized controlled trial

Background and objectives

The aim of this prospective, multi-centered and multi-arm parallel randomized trial was to test the hypothesis that modified sitting positions including hamstring stretch position (HSP) and squatting position (SP) would reduce needle - bone contact events and increase the success rate of combined spinal - epidural anesthesia (CSEA) compared to traditional sitting position (TSP) in patients undergoing total knee or hip arthroplasty.

Patients and methods

Three hundred and sixty American Society of Anesthesiologists (ASA) I-III patients, aged between 45-85 years were randomly allocated to one of three groups using computer-generated simple randomization: group TSP (n = 120), group HSP (n = 120), and group SP (n = 120). Primary outcome measures were the number of needle-bone contact and success rates. Secondary outcome measure was the ease of interspinous space identification.

Results

Seven patients in group SP and four of HSP could not tolerate their position and were excluded. Number of needle-bone contact, success rates, and grade of interspinous space identification were similar between groups (p = 1.000). Independent of positioning, the success rates were higher in patients whose interspinous space was graded as easy compared to difficult or impossible (p < 0.001). Success rates reduced, interspinous space identification became more challenging, and number of needle – bone contact increased as patient’s body mass index (BMI) increased (p < 0.001).

Conclusion

SP and HSP may be used as alternatives to the TSP. BMI and ease of interspinous space identification may be considered important determinants for CSEA success.

Predicting difficult spinal anesthesia: development of a neuraxial block assessment score

BACKGROUND

Spinal anesthesia is a commonly performed procedure with unpredictable difficulty. The objective of this study was to predict a difficult lumbar spinal anesthesia with clinical elements that are easy to collect.

METHODS

A questionnaire-based, observational study named NBA, conducted from February 2018 to June 2018. The questions regarded clinical elements and the eventual spinal anesthesia difficulty encountered. A total of 427 questionnaires were filled by the operators. The clinical elements were selected upon literature search and have been integrated with new ones. All the answers were recorded from the anesthesiologist performing the procedure.

RESULTS

The NBA Score was derived from a total number of 427 questionnaires. Among them, 26 patients had "previous history of difficult spinal anesthesia;" 277 had "spinous processes not visible;" 83 had "spinous processes not palpable;" 77 had "spinal deformities" and 28 had "previous spinal surgery" in the puncture area; 138 patients received lumbar spinal anesthesia in lateral position. There were 328 (76.8%) single puncture successes. Seventy-nine (18.5%) patients required more than one skin puncture to obtain a successful spinal anesthesia. 20 (4.7%) required an alternative anesthesia technique (general anesthesia). Multivariate analysis indicated that each element is a risk factors for difficult spinal anesthesia, except for previous spinal surgery.

CONCLUSIONS

The combination of more than one element increased the chance of a second skin puncture of more than 50%. This work proposes a simple clinical scoring system predicting the probability of a difficult spinal anesthesia.

A Prospective Observational Study to Determine the Predictors of Increased Number of Attempts at Labour Epidural Placement

Objective

Multiple attempts at labour epidural placement result in patient discomfort and high incidence of complications. Identifying the factors that lead to more than one attempt would help anaesthesiologists prepare in advance such as getting expert help and additional equipment, patient counselling or planning alternative management.

Methods

This prospective observational study was conducted on 500 patients from July 2017 to June 2018 after obtaining approval from the institutional Ethics Review Committee. The study patients consisted of full-term parturient women who were admitted in the labour room suite of Aga Khan Hospital requesting for labour epidural and consented to participate in the study. A predesigned form was used to collect the following data: number of attempts at epidural insertion and factors such as patients' demographics, cervical dilatation, anatomical grading of spine according to visibility and palpation of spinous process and vertebral interspace, experience level of the anaesthesiologist, patient satisfaction and pain score during labour.

Results

The average age of the patients was 28.11±4.02 years. The total number of epidural attempts varied between one and four; the median number of attempts was 1 [IQR=1-2]. Anatomical grade of the spine was the only factor that was significantly associated with more than one attempt at epidural insertion (p=0.0005). Patient satisfaction was negatively associated with the number of attempts (p=0.04), but mean pain difference at different time points during the course of labour was not statistically significant between patients with one attempt and those with more than one attempt.

Conclusion

Determining the anatomical grade of the spine is the most reliable method for predicting a technically difficult neuraxial block that requires more than one attempt at epidural insertion.

Influence of age, laterality, patient position, and spinal level on the interlamina space for spinal puncture

BACKGROUND AND OBJECTIVES

The lumbar interlamina space height is an important determinant of successful spinal puncture. We aimed to evaluate the influence of age, laterality, patient position, and spinal level on the height of the interlamina window using ultrasonography.

METHODS

Ultrasonographic examination was performed in 20 adult patients aged under 40 years (group Y) and 20 patients aged over 60 years (group O). We set three primary outcomes: difference in the interlamina height of the ligamentum flavum-dura mater complex (LFD) according to (1) age, (2) laterality, and (3) position. For secondary outcomes, the degree of ultrasonography visualization (poor, intermediate, or good) and the depths from the skin to LFD and to anterior complex were also measured on right and left paramedian sagittal oblique view in both lateral and sitting positions at L3/4, L4/5, and L5/S1 levels. All variables were analyzed in association with age, laterality, patient position, and spinal level.

RESULTS

The interlamina height of LFD was higher, and the degree of visualization was better in group Y than in group O. It differed depending on laterality in paramedian sagittal oblique view images in the same patients at all spinal levels. The interlamina height of LFD was the largest at L5/S1 level in both groups. Position had little influence on the interlamina height of LFD.

CONCLUSIONS

Scanning both sides and all spinal levels before selecting a puncture site for ultrasound-guided spinal anesthesia is recommended. The L5/S1 spinal level is a good option for spinal puncture in the elderly.

TRIAL REGISTRATION NUMBER

NCT03929874.

Anatomical predicting factors of difficult spinal anesthesia in patients undergoing cesarean section: An observational study

Objectives:

Although Spinal anesthesia is the most common and safe anesthetic method for patients undergoing cesarean section, difficult access to it is a frequent problem in operating theaters. The predictive factors for the difficulty of spinal anesthesia in patients undergoing cesarean section were investigated.

Methods:

A total of 110 pregnant women, single-stranded, aged 18-40 years old and ASA class I or II candidates for elective cesarean section with spinal anesthesia were studied. Demographic information, body appearance, ability to bend the back of the patient was recoded. Also the position of the anatomical landmarks of the lumbar spine, the presence or absence of deformity in the spinal column lumbar was recorded for all patients.

Results:

The correlation coefficient of age, weight, body mass index, general body appearance, retention ability, anatomical signs of the spinal column (touching the spinous process) and the interval between the vertebra with the difficulty of spinal anesthesia were statistically significant (p<0.05). Complications after spinal anesthesia had a statistically significant relationship with the difficulty of performing spinal blockade (p: 0.006).

Conclusion:

Increasing age, weight, body mass index, reducing the ability to bend the waist, the non-touching of the spinous process and interstitial space causes the difficulty of performing spinal anesthesia in patients undergoing cesarean section. The results can contribute to determining and designing a spinal blockade scoring system based on the patient’s characteristics and effective factors before the surgery, to facilitate the technique by anesthesiologist.

Predictors of difficult epidural placement in pregnant women: A trainees' perspective

BACKGROUND AND AIMS

Epidural analgesia is believed to be the most difficult technique to learn for a trainee. The reason for this is not only inexperience of the provider and the complexity of the technique but also patient factors like obesity, spinal deformity and others which makes the epidural placement difficult. The aim of this study was to evaluate some of the common risk factors for difficult epidural placement as perceived by the anesthesia providers during training, with varying level of experience.

MATERIAL AND METHODS

This prospective observational study includes patients who received epidural placement for labor analgesia. Data recorded on these patients included age, height, weight, body mass index (BMI), ease of palpation of the spinous process, level of epidural placement, number of attempts, time taken for epidural placement and experience of the provider. The association between the variables were assessed using logistic regression for first attempt success and Cox proportional hazard ratio for time to epidural placement.

RESULTS

A total of 373 patients received epidural placement for labor analgesia. The mean BMI at the time of placement was 34. The first attempt success rate for the placement of epidural was 67% (n = 273). Women with well palpable spinous process were 3.3 times more likely to have a successful first attempt placement irrespective of the provider experience or BMI [3.39 (1.77-6.51), P < 0.001]. The time to placement was shorter in patients with good anatomical landmarks [1.58 (1.20-2.07), P < 0.001) and when performed by a trainee who had performed a minimum of 20 epidural procedures [1.57 (1.26-1.94), P < 0.001).

CONCLUSION

Inability to palpate the spinous process contributes to multiple attempts at epidural placement when performed by a trainee.

Development and validation of a predictive risk factor model for epidural re-siting in women undergoing labour epidural analgesia: a retrospective cohort study

Background

Epidural catheter re-siting in parturients receiving labour epidural analgesia is distressing to the parturient and places them at increased complications from a repeat procedure. The aim of this study was to develop and validate a clinical risk factor model to predict the incidence of epidural catheter re-siting in labour analgesia.

Methods

The data from parturients that received labour epidural analgesia in our centre during 2014–2015 was used to develop a predictive model for epidural catheter re-siting during labour analgesia. Multivariate logistic regression analysis was used to identify factors that were predictive of epidural catheter re-siting. The forward, backward and stepwise variable selection methods were applied to build a predictive model, which was internally validated. The final multivariate model was externally validated with the data collected from 10,170 parturients during 2012–2013 in our centre.

Results

Ninety-three (0.88%) parturients in 2014–2015 required re-siting of their epidural catheter. The training data set included 7439 paturients in 2014–2015. A higher incidence of breakthrough pain (OR = 4.42), increasing age (OR = 1.07), an increased pain score post-epidural catheter insertion (OR = 1.35) and problems such as inability to obtain cerebrospinal fluid in combined spinal epidural technique (OR = 2.06) and venous puncture (OR = 1.70) were found to be significantly predictive of epidural catheter re-siting, while spontaneous onset of labour (OR = 0.31) was found to be protective. The predictive model was validated internally on a further 3189 paturients from the data of 2014–2015 and externally on 10,170 paturients from the data of 2012–2013. Predictive accuracy of the model based on C-statistic were 0.89 (0.86, 0.93) and 0.92 (0.88, 0.97) for training and internal validation data respectively. Similarly, predictive accuracy in terms of C-statistic was 0.89 (0.86, 0.92) based on 2012–2013 data.

Conclusion

Our predictive model of epidural re-siting in parturients receiving labour epidural analgesia could provide timely identification of high-risk paturients required epidural re-siting.

Prospective evaluation of point-of-care ultrasound for pre-procedure identification of landmarks versus traditional palpation for lumbar puncture

BACKGROUND

The objective of this study is to determine if point-of-care ultrasound (POCUS) pre-procedure identification of landmarks can decrease failure rate, reduce procedural time, and decrease the number of needle redirections and reinsertions when performing a lumbar puncture (LP).

METHODS

This was a prospective, randomized controlled trial comparing POCUS pre-procedure identification of landmarks versus traditional palpation for LP in a cohort of patients in the emergency department and intensive care unit.

RESULTS

A total of 158 patients were enrolled. No significant difference was found in time to completion, needle re-direction, or needle re-insertion when using POCUS when compared to the traditional method of palpation.

CONCLUSION

Consistent with findings of previous studies, our data indicate that there was no observed benefit of using POCUS to identify pre-procedure landmarks when performing an LP.

Optimal point of insertion of the needle in neuraxial blockade using a midline approach: study in a geometrical model

Performance of neuraxial blockade using a midline approach can be technically difficult. It is therefore important to optimize factors that are under the influence of the clinician performing the procedure. One of these factors might be the chosen point of insertion of the needle. Surprisingly few data exist on where between the tips of two adjacent spinous processes the needle should be introduced. A geometrical model was adopted to gain more insight into this issue. Spinous processes were represented by parallelograms. The length, the steepness relative to the skin, and the distance between the parallelograms were varied. The influence of the chosen point of insertion of the needle on the range of angles at which the epidural and subarachnoid space could be reached was studied. The optimal point of insertion was defined as the point where this range is the widest. The geometrical model clearly demonstrated, that the range of angles at which the epidural or subarachnoid space can be reached, is dependent on the point of insertion between the tips of the adjacent spinous processes. The steeper the spinous processes run, the more cranial the point of insertion should be. Assuming that the model is representative for patients, the performance of neuraxial blockade using a midline approach might be improved by choosing the optimal point of insertion.