A systematic review of randomized controlled trials that evaluate strategies to avoid epidural vein cannulation during obstetric epidural catheter placement

Epidemiologic investigation on neurological complications following neuraxial anesthesia in 2.7 million cases in Southwest China

Neuraxial anesthesia provides effective anesthesia and analgesia for surgery, but may cause neurological complications. The rate of neurological complications in China remains unclear. This study conducted a retrospective epidemiological investigation of neurological complications following neuraxial anesthesia in Guangxi, southwest China. This survey used the "Golden Data" platform to distribute questionnaires to anesthesiology departments across hospitals of varying levels in Guangxi, gathering data on neuraxial anesthesia methods and associated neurological complications from 2013 to 2022. Detailed patient information was recorded, with missing data supplemented by phone. The Adverse Event Reporting System was also utilized to verify and supplement cases, supported by peer review. The study analyzed the incidence and clinical characteristics of neurological complications after neuraxial anesthesia. A comprehensive survey was conducted across 243 hospitals, encompassing 2,723,615 cases of neuraxial anesthesia. The survey identified 1208 cases of neurological complications, with an incidence of 0.44‰, primarily occurring in patients undergoing obstetrics, gynecology, orthopedics, urology, and general surgery. The complications included transient nerve syndrome (999 cases), spinal injury (188 cases), cauda equina syndrome (13 cases), spinal hematoma (5 cases), anterior spinal artery syndrome (2 cases), and conus medullaris injury (1 case). The incidence of neurological complications associated with combined spinal-epidural anesthesia (0.53‰) was significantly higher than that of epidural anesthesia (0.21‰) and spinal anesthesia (0.35‰) (P < 0.001). Among the patients, 97.3% achieved full recovery, while 2.7% (30 cases) suffered permanent neurological damage. Although neurological complications are relatively rare, comprehensive preoperative assessment, adherence to standardized protocols, and vigilance regarding potential complications are essential.

Comparative study of labour analgesia onset with injection of loading dose through epidural needle versus catheter: A prospective, double-blinded, randomised clinical trial

BACKGROUND

Rapid onset of epidural analgesia is an important concern for the parturient. Commonly, the local anaesthetic mixture is administered through the epidural catheter. Drugs administered through the epidural needle might decrease the onset time and enhance the spread of medication within the epidural space.

OBJECTIVES

The primary aim of this study was to compare the onset time of analgesia when a loading dose of dilute local anaesthetic opioid mixture was injected through either the Tuohy needle or a single end-hole epidural catheter.

DESIGN

A prospective, double-blinded, randomised clinical trial.

SETTING

Single university hospital, from November 2022 to August 2023.

PARTICIPANTS

A total of 200 healthy nulliparous women who requested epidural analgesia for labour were randomly allocated to the needle group (n = 100) or the catheter group (n = 100).

INTERVENTIONS

In the needle group, after identification of the epidural space, a test dose of 3 ml 0.1% ropivacaine with 0.3 μg ml-1 sufentanil was injected through the Tuohy needle followed 3 min later by a 15 ml loading dose of the same mixture over 30 s. Then the catheter was inserted into the epidural space. In the catheter group, after identification of the epidural space, a catheter was advanced into the epidural space and the ropivacaine/sufentanil mixture was injected in an identical manner though the catheter.

MAIN OUTCOME MEARSURES

The primary outcome was the onset time of labour analgesia (defined as the time from drug administration to adequate analgesia). Adequate analgesia was defined as a visual analogue score 10 mm or less during uterine contractions.

RESULTS

Median [IQR] onset time of labour analgesia did not differ significantly between the two groups (needle group: 20 [16 to 30] minutes; catheter group: 20 [15 to 25] minutes, P = 0.232).

CONCLUSION

Compared with bolus injection though a single end-hole epidural catheter, injection through the epidural needle did not shorten the analgesia onset time for adequate labour analgesia.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT05594771).

Relationship between epidural catheter migration beneath the skin and subcutaneous fat thickness assessed using postoperative CT imaging: a retrospective cross-sectional study

PURPOSE

The causes of epidural catheter migration beneath the skin have not been previously investigated. We hypothesized that greater subcutaneous fat thickness might be associated with increased catheter migration beneath the skin.

METHODS

We conducted a retrospective cross-sectional study of patients who had undergone combined general and epidural anesthesia, selecting individuals who received thoracic and abdominal CT scans within the first 5 postoperative days. Needle depth was defined as the distance from the needle tip to the skin surface when the anesthesiologist determined that the needle tip had reached the epidural space. We measured the length of the epidural catheter from the skin surface to the epidural space (catheter length), and subcutaneous fat thickness (fat thickness) using CT imaging. Migration distance was calculated by subtracting needle depth from catheter length.

RESULTS

We analyzed 127 patients (72 males), all undergoing epidural catheter insertion in the left lateral decubitus position via a paramedian approach. The median age of the patients was 71 years. Epidural catheters were postoperatively found to substantially curve beneath the skin. Regression analysis revealed no significant influence of fat thickness on catheter length (regression coefficient 0.10, 95% confidence interval [CI]: - 0.17, 0.38). However, it indicated a positive correlation between fat thickness and needle depth (regression coefficient 0.50, 95% CI: 0.30, 0.70), and a negative correlation between fat thickness and migration distance (regression coefficient - 0.40, 95% CI: - 0.65, - 0.14).

CONCLUSION

We found a negative correlation between epidural catheter migration beneath the skin and subcutaneous fat thickness. Anesthesiologists should be aware of the possibility of substantial subcutaneous curving of the catheter, especially in patients with scant subcutaneous fat.

Tacrolimus-Induced Akinetic Mutism or Epidural Catheter Migration: A Case Report

Differential diagnosis of the underlying cause of new-onset total body paralysis can be challenging and unsatisfying. In akinetic mutism, a rare side effect of tacrolimus, patients become apathetic, mute, and lose voluntary muscle movement. Epidural subarachnoid migration can present with similar symptoms. Delayed emergence/paralysis after anesthesia can include the common culprits of residual operative medications, stroke, as well as tacrolimus-induced akinetic mutism and thoracic epidural migration. We present a case of new-onset total body paralysis, presenting on postoperative day 1 following a double-lung transplant in a patient started on tacrolimus with a thoracic epidural catheter in place.

Influence of maternal position during combined spinal-epidural anesthesia for labor analgesia on technical difficulties and complications

PURPOSE

Generally, combined spinal-epidural anesthesia (CSEA) for labor analgesia is performed in the lateral or sitting position; however, only few studies have investigated the effect of maternal position on labor analgesia induction. We aimed to retrospectively assess the influence of maternal position on induction time and complications.

METHODS

We retrospectively analyzed anesthetic and medical records regarding labor analgesia in 201 parturients treated between January 2019 and November 2019. Patients were classified into 2 groups based on their position (sitting or lateral) during induction. The primary outcome was the time required for CSEA induction. We compared 2 groups on the primary outcome and the occurrences of other complications during CSEA induction using hyperbaric bupivacaine. Moreover, we performed multiple linear regression analysis to identify independent factors associated with induction time.

RESULTS

There was no significant between-group difference in the time required for induction. Multiple linear regression analysis revealed an independent association of the distance from the skin to the epidural space with the time required for induction. The lateral group had a significantly higher incidence of paresthesia than the sitting group (P = 0.028). The lateral group had a significantly higher ephedrine requirement (P < 0.001) than the sitting group.

CONCLUSION

Maternal position was not associated with the time required for CSEA induction. However, the sitting group had a lower paresthesia occurrence and ephedrine requirement than the lateral group. Other technical complications were not associated with maternal position during CSEA induction.

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.

What's New in Neuraxial Labor Analgesia

Purpose of Review

This article provides an update of recent practice trends in neuraxial labor analgesia. It reviews available evidence regarding management of labor pain in obstetric patients with COVID-19, serious adverse events in obstetric anesthesia to help inform risk/benefit decisions, and increasingly popular neuraxial labor analgesia techniques and adjuvants. State-of-the-art modes of epidural drug delivery are also discussed.

Recent Findings

There has recently been a focus on several considerations specific to obstetric anesthesia, such as anesthetic management of obstetric patients with COVID-19, platelet thresholds for the safe performance of neuraxial analgesia in obstetric patients with thrombocytopenia, and drug delivery modes for initiation and maintenance of neuraxial labor analgesia.

Summary

Neuraxial labor analgesia (via standard epidural, dural puncture epidural, and combined spinal epidural techniques) is the most effective therapy to alleviate the pain of childbirth. SARS-CoV-2 infection is not, in and of itself, a contraindication to neuraxial labor analgesia or cesarean delivery anesthesia. Early initiation of neuraxial labor analgesia in patients with COVID-19 is recommended if not otherwise contraindicated, as it may reduce the need for general anesthesia should emergency cesarean delivery become necessary. Consensus regarding platelet thresholds for safe initiation of neuraxial procedures has historically been lacking. Recent studies have concluded that the risk of spinal epidural hematoma formation after neuraxial procedures is likely low at or above an imprecise range of platelet count of 70–75,000 × 10⁶/L. Thrombocytopenia has been reported in obstetric patients with COVID-19, but severe thrombocytopenia precluding initiation of neuraxial anesthesia is extremely rare. High neuraxial blockade has emerged as one of the most common serious complications of neuraxial analgesia and anesthesia in obstetric patients. Growing awareness of factors that contribute to failed conversion of epidural labor analgesia to cesarean delivery anesthesia may help avoid the risks associated with performance of repeat neuraxial techniques and induction of general anesthesia after failed epidural blockade. Dural puncture techniques to alleviate the pain of childbirth continue to become more popular, as do adjuvant drugs to enhance or prolong neuraxial analgesia. Novel techniques for epidural drug delivery have become more widely disseminated.

Epidural test dose in obstetric patients: should we still use it?

PURPOSE OF REVIEW

As the application of a test dose after epidural catheter insertion in obstetrics has recurrently been associated with serious adverse events affecting both maternal and foetal outcomes, the question whether to test or not remains a controversial issue.

RECENT FINDINGS

Present guidelines do not provide clear recommendations in this regard and several recent surveys indicate a heterogeneity in clinical routine.

SUMMARY

Physiological alterations during pregnancy and labour restrict the use and also the validity of traditional test agents. Epinephrine is not appropriate to detect a vascular insertion in labour and the application of a local anaesthetic test dose may lead to dose-dependent fatal consequences should the catheter be intrathecal, due to an increased sensitivity in parturients. Given the current practice of opioid-amended-low-concentration epidurals, the waiving of a test dose results at worst in a failed epidural, a stark contrast to the potentially severe to fatal complications of a 'traditional' test dose. Hence, an originally preventive measure providing potentially more harm than the consequences of the situation aimed to prevent, should not be recommended. A simple fractionated administration of the initial analgesic dose seems reasonable though.

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.

Intrathecal Migration of an Epidural Catheter While Using a Programmed Intermittent Epidural Bolus Technique for Labor Analgesia Maintenance: A Case Report

We describe a case of intrathecal migration of a wire-reinforced epidural catheter in a parturient who received epidural labor analgesia. Epidural analgesia was initiated with a combined-spinal epidural technique and maintained by programmed intermittent epidural boluses. Epidural catheter aspiration after insertion was negative for cerebrospinal fluid. The patient's response to the first four doses of local anesthetic was consistent with epidural drug delivery. After the fifth dose, she developed a complete lower extremity motor block, hypotension, and high sensory blockade. Catheter aspiration was then positive for cerebrospinal fluid. After symptom resolution, labor pain was successfully managed with this inadvertent intrathecal catheter.

Comparison of the acoustic windows for the thoracic paramedian epidural approach after shoulder rotation: The lateral decubitus versus the sitting position

BACKGROUND

The aim of this study was to compare the mean lengths of the posterior longitudinal ligament (PLL) as the acoustic window during the thoracic paramedian epidural approach after shoulder rotation, while subjects were in the lateral decubitus or in the sitting position.

METHODS

Thirty-two adult male volunteers were placed in the right decubitus position or sitting position on a horizontal operating table. To obtain an optimal ultrasound view for the PLL on the right side, thoracic spinal ultrasonography was performed at the T6/7 interspace using the paramedian oblique sagittal plane. PLL length was measured on the ultrasound image before and after right shoulder rotation.

RESULTS

Before shoulder rotation, the difference in mean PLL length between the sitting (11.1±1.3mm) and lateral decubitus (10.7±1.2mm) positions was not statistically significant (P=0.05). Within-position, the before and after comparison revealed that after shoulder rotation, PLL length was significantly increased to 12.2±1.4mm (P<0.001) and 12.0±1.5mm (P<0.001) in the sitting and lateral decubitus positions, respectively. However, after shoulder rotation the between-position difference in mean PLL length was not statistically significant (P=0.50) CONCLUSIONS: Shoulder rotation did not result in a statistically significant difference in the dimension of the acoustic target window for paramedian thoracic epidural access in the sitting compared to the lateral decubitus position.

Initiation of labor analgesia with injection of local anesthetic through the epidural needle compared to the catheter

Background

The rationale for injection of epidural medications through the needle is to promote sooner onset of pain relief relative to dosing through the epidural catheter given that needle injection can be performed immediately after successful location of the epidural space. Some evidence indicates that dosing medications through the epidural needle results in faster onset and improved quality of epidural anesthesia compared to dosing through the catheter, though these dosing techniques have not been compared in laboring women. This investigation was performed to determine whether dosing medication through the epidural needle improves the quality of analgesia, level of sensory blockade, or onset of pain relief measured from the time of epidural medication injection.

Methods

In this double-blinded prospective investigation, healthy term laboring women (n=60) received labor epidural placement upon request. Epidural analgesia was initiated according to the assigned randomization group: 10 mL loading dose (0.125% bupivacaine with fentanyl 2 µg/mL) through either the epidural needle or the catheter, given in 5 mL increments spaced 2 minutes apart. Verbal rating scale (VRS) pain scores (0–10) and pinprick sensory levels were documented to determine the rates of analgesic and sensory blockade onset.

Results

No significant differences were observed in onset of analgesia or sensory blockade from the time of injection between study groups. The estimated difference in the rate of pain relief (VRS/minute) was 0.04 (95% CI: −0.01 to 0.11; p=0.109), and the estimated difference in onset of sensory blockade (sensory level/minute) was 0.63 (95% CI: −0.02 to 0.15; p=0.166). The time to VRS ≤3 and level of sensory block 20 minutes after dosing were also similar between groups. No differences in patient satisfaction, or maternal or fetal complications were observed.

Conclusion

This investigation observed that epidural needle and catheter injection of medications result in similar onset of analgesia and sensory blockade, quality of labor analgesia, patient satisfaction, and complication rates.

The influence of epidural catheter on the incidence of intravascular injection during caudal block

OBJECTIVE

The aim of this study was to analyze the influence of epidural catheters on the incidence of intravascular injection and to identify possible predictors of intravascular injection in patients undergoing a caudal block using fluoroscopy.

METHODS

A total of 154 patients scheduled to receive a caudal block were randomized into group N (those without epidural catheter) or group C (those with epidural catheter). Demographic and clinical data were recorded and analyzed.

RESULTS

The incidence of intravascular injection was 15.6% in group N, 6.5% in group C, and 11.0% overall, without statistical differences between the two groups (P = 0.105). Univariate analysis revealed that blood at hub (P = 0.047) and positive aspiration test (P = 0.045) were more frequently observed in group N than in group C. Quality of analgesia was significantly higher in group C than in group N (P = 0.029). Multivariate analysis identified older age (P = 0.024), blood at hub (P = 0.003), and positive aspiration test (P = 0.001) as predictors of intravascular injection.

CONCLUSIONS

In this study, while the incidence of intravascular injection during caudal blocks was less frequent with epidural catheter use, it was not statistically significant. However, a caudal block using an epidural catheter provided a lower incidence of blood at hub, fewer positive aspiration tests, and superiority in pain improvement.

Localization of epidural space: A review of available technologies

Although epidural analgesia is widely used for pain relief, it is associated with a significant failure rate. Loss of resistance technique, tactile feedback from the needle, and surface landmarks are traditionally used to guide the epidural needle tip into the epidural space (EDS). The aim of this narrative review is to critically appraise new and emerging technologies for identification of EDS and their potential role in the future. The PubMed, Cochrane Central Register of Controlled Clinical Studies, and Web of Science databases were searched using predecided search strategies, yielding 1048 results. After careful review of abstracts and full texts, 42 articles were selected to be included. Newer techniques for localization of EDS can be broadly classified into techniques that (1) guide the needle to the EDS, (2) identify needle entry into the EDS, and (3) confirm catheter location in EDS. An ideal method should be easy to learn and perform, easily reproducible with high sensitivity and specificity, identifies inadvertent intrathecal and intravascular catheter placements with ease, feasible in perioperative setting and have a cost-benefit advantage. Though none of them in their current stages of development qualify as an ideal method, many show tremendous potential. Some techniques are useful in patients with difficult spinal anatomy and infants, and thus are complementary to traditional methods. In addition to improving the existing technology, future research should aim at proving the superiority of these techniques over traditional methods, specifically regarding successful EDS localization, better safety profile, and a favorable cost-benefit ratio.

Anesthetic Implications of an Obstetric Patient with Blue Rubber Bleb Nevus Syndrome

Blue rubber bleb nevus syndrome, a syndrome of multifocal venous malformations, has been reported rarely during pregnancy. This syndrome has been associated with airway lesions in some patients and neuraxial abnormalities in other patients. We report the anesthetic and obstetric management of a patient with an extensive distribution of both airway and neuraxial lesions.

The Effects of Shoulder Rotation on the Acoustic Window for Thoracic Paramedian Epidural Approach in the Lateral Decubitus Position

BACKGROUND AND OBJECTIVES

The aim of this study was to examine whether shoulder rotation increases the length of the posterior longitudinal ligament (PLL) in the lateral decubitus position.

METHODS

Thirty-four adult male volunteers were placed in the right or left lateral decubitus and flexion position on a horizontal operating table. Thoracic spinal ultrasonography was performed using the paramedian oblique sagittal plane to obtain the optimal ultrasound view for the PLL on the dependent side. The lengths of the PLL were measured at the T6/7 and T9/10 interspaces before and after ipsilateral 30-degree shoulder rotation.

RESULTS

In the right lateral decubitus position, the ipsilateral shoulder rotation increased the mean (SD) of the PLL from 7.4 (2.8) to 8.4 (2.6) mm (P = 0.006) at the T6/7 level and from 8.4 (2.9) to 10.6 (2.8) mm (P < 0.0001) at the T9/10 level. Similarly, in the left lateral decubitus position, the ipsilateral shoulder rotation increased the mean (SD) of the PLL from 8.0 (2.6) to 9.1 (2.6) mm (P = 0.001) at the T6/7 level and from 9.3 (2.8) to 11.8 (3.1) mm (P < 0.0001) at the T9/10 level.

CONCLUSIONS

Shoulder rotation significantly increased the dimension of the acoustic target window for paramedian thoracic epidural access in the lateral decubitus position at both T6/7 and T9/10 levels. Further clinical studies are needed to investigate the effect of shoulder rotation on thoracic epidural access.

Lateral deviation of four types of epidural catheters from the lumbar epidural space into the intervertebral foramen

Background

During epidural anesthesia, the catheter tip occasionally deviates from the epidural space into the intervertebral foramen, resulting in inadequate anesthesia.

Methods

During postoperative plain radiography, iohexol was injected via the epidural catheter to determine its position and to observe the spread of the material. After exclusion of seven patients with catheters that migrated into the subcutaneous area and 25 patients with no evidence of the contrast medium, 415 patients were evaluated. We retrospectively compared patients to determine whether the incidence of deviation into the intervertebral foramen differed between four types of epidural catheters. We also investigated the load applied to the catheter tip using a Shimadzu Autograph AG-X-500 N-111 universal testing machine.

Results

Deviation of the epidural catheter into the intervertebral foramen was observed in eight and 33 patients in the Hakko and Perifix Soft tip catheter groups, respectively. The incidence of deviation was higher in the Perifix Soft tip catheter group, and lower in the FlexTip Plus and Perifix FX catheter groups. A rapid increase was observed in the force exerted on the tips of the Hakko and Perifix Soft tip catheters, while the force transmitted to the tips of the FlexTip Plus and Perifix FX catheters gradually increased and then reached a plateau at a low level.

Conclusions

The incidence of deviation was significantly lower with spiral-type catheters than with other types of catheters. This might be attributable to the gradual transmission of a lower level of force to the tip in spiral-type catheters.

Systematic Reviews of Anesthesiologic Interventions Reported as Statistically Significant: Problems with Power, Precision, and Type 1 Error Protection

BACKGROUND

The GRADE Working Group assessment of the quality of evidence is being used increasingly to inform clinical decisions and guidelines. The assessment involves explicit consideration of all sources of uncertainty. One of these sources is imprecision or random error. Many published meta-analyses are underpowered and likely to be updated in the future. When data are sparse and there are repeated updates, the risk of random error is increased. Trial Sequential Analysis (TSA) is one of several methodologies that estimates this increased risk (and decreased precision) in meta-analyses. With nominally statistically significant meta-analyses of anesthesiologic interventions, we used TSA to estimate power and imprecision in the context of sparse data and repeated updates.

METHODS

We conducted a search to identify all systematic reviews with meta-analyses that investigated an intervention that may be implemented by an anesthesiologist during the perioperative period. We randomly selected 50 meta-analyses that reported a statistically significant dichotomous outcome in their abstract. We applied TSA to these meta-analyses by using 2 main TSA approaches: relative risk reduction 20% and relative risk reduction consistent with the conventional 95% confidence limit closest to null. We calculated the power achieved by each included meta-analysis, by using each TSA approach, and we calculated the proportion that maintained statistical significance when allowing for sparse data and repeated updates.

RESULTS

From 11,870 titles, we found 682 systematic reviews that investigated anesthesiologic interventions. In the 50 sampled meta-analyses, the median number of trials included was 8 (interquartile range [IQR], 5-14), the median number of participants was 964 (IQR, 523-1736), and the median number of participants with the outcome was 202 (IQR, 96-443). By using both of our main TSA approaches, only 12% (95% CI, 5%-25%) of the meta-analyses had power ≥ 80%, and only 32% (95% CI, 20%-47%) of the meta-analyses preserved the risk of type 1 error <5%.

CONCLUSIONS

Most nominally statistically significant meta-analyses of anesthesiologic interventions are underpowered, and many do not maintain their risk of type 1 error <5% if TSA monitoring boundaries are applied. Consideration of the effect of sparse data and repeated updates is needed when assessing the imprecision of meta-analyses of anesthesiologic interventions.

Impact of thoracic epidural catheter threading distance on analgesia during the first 24 hours following thoracotomy: a randomized controlled trial

PURPOSE

The purpose of this prospective randomized controlled trial was to determine the impact of thoracic epidural catheter threading distance on analgesia quality after thoracotomy.

METHODS

We randomly assigned 120 elective thoracotomy patients to a thoracic epidural catheter threading distance of 3, 5, or 7 cm (groups 3CM, 5CM, and 7CM, respectively). Epidural bupivacaine 0.1% with fentanyl 2 µg·mL(-1) was administered according to a standardized protocol. Epidural analgesia quality was assessed at 60 min and 24 hr postoperatively for four measures: incidence of non-functioning epidurals; numerical rating score (NRS) < 4 at rest, while coughing, and during wound palpation; cold perception at the wound site; and cumulative dose of analgesic medication used. Our primary hypothesis was that, compared to threading distances of 3 and 5 cm, a threading distance of 7 cm was not inferior at providing an NRS < 4 while coughing at 60 min postoperatively, with a non-inferiority margin of 25% (absolute value) being significant.

RESULTS

The incidence of NRS < 4 while coughing at 60 min was 74% (29/39) in group 7CM compared with 68% (54/80) in the combined 3CM and 5CM groups (absolute difference 7%; 95% confidence interval -11 to 23; P = 0.29). At both 60 min and 24 hr, differences between groups were similar regarding the number of non-functioning epidurals, NRS < 4, and suppressed cold sensation. Analgesic doses were similar in the three groups.

CONCLUSIONS

This study found that a thoracic epidural catheter threading distance of 7 cm in the epidural space was not inferior to distances of 3 cm and 5 cm with respect to pain scores at 60 min postoperatively. This study was not powered to examine differences that could have clinical significance that were less than our a priori 25% non-inferiority margin.

Effects of epinephrine in the epidural space on the incidence of blood vessel injury by epidural catheter insertion for cesarean section: a prospective, randomized, double-blind study

STUDY OBJECTIVE

To evaluate the effects of epinephrine (1:200,000) in the epidural space on the incidence of blood vessel injury by epidural catheter insertion for cesarean section.

DESIGN

Prospective observational study.

SETTING

University-affiliated teaching hospital.

PATIENTS

Four hundred laboring women with singleton cephalic presentations at term who underwent cesarean section and requested continuous epidural analgesia.

INTERVENTIONS

Predistension of 5 mL of isotonic sodium chloride solution containing epinephrine (1:200,000) or 5 mL of isotonic sodium chloride solution through an epidural needle before catheter insertion.

MEASUREMENTS

Cases with bloody fluid in the epidural needle or catheter during catheter insertion, aspiration of frank blood from the epidural catheter, and blood noted in the caudal end of the epidural catheter upon removal were recorded.

MAIN RESULTS

Eight parturients were excluded from the analysis for technical reasons. There were no significant differences between patients in the 2 groups with respect to cases with bloody fluid in the epidural needle during catheter insertion (7.6% vs 9.8%, P = .44), the epidural catheter during catheter placement (6.0% vs 6.7%, P = .80), aspiration of frank blood in the epidural catheter (1.0% vs 1.0 %, P = .98), and blood noted in the caudal end of the epidural catheter upon removal (27.3% vs 30.4 %; P > .49).

CONCLUSION

Twenty-five micrograms of epinephrine (1:200,000) in the epidural space does not reduce the incidence of blood vessel injury induced by insertion of an epidural catheter.

[Epidural anaesthesia: Simulated intravascular test dose with S(+) ketamine, lidocaine and adrenaline. A prospective, randomized, double blind and placebo controlled study]

OBJECTIVE

The use of a test dose in epidural anaesthesia is a safety recommendation. However specificity and sensitivity of the drugs used with this indication have been not conclusive. The main objective of this study was to compare the effectiveness and the adverse effects of a simulated intravascular test dose of adrenaline, lidocaine and S(+)-ketamine.

MATERIAL AND METHODS

A prospective, randomized, double blinded, placebo controlled study was designed. ASA I patients scheduled for elective surgery were included. These were randomized to the following study groups: S(+)-ketamine 0.5 mg.kg-1 (S+K group), 5% lidocaine 1.5 mg.kg-1 (L5% group), adrenaline 15μg (ADR group), and physiological saline 3 ml (SF group; control group). An evaluation was made during the first 15 minutes after the study drug was administered. Variables including heart rate (HR) systolic and diastolic blood pressure (sBP and dBP), mean arterial pressure (MAP), and SpO2 were recorded at 0 min (baseline) and at 2, 5, 8, 10 and 15 minutes after drug injection. An increase of at least 20 beats per minute (bpm) in relation to the baseline measurement was considered a positive result, as was an increase sBP >15 mmHg. The clinical effects described as related to iv injection of the study drugs recorded were: sedation-hypnosis, dizziness, nystagmus, metallic taste perception, perioral or facial paresthesias, tinnitus, as well as any other effect the patients mentioned. Sensitivity and specificity were calculated as was the percent increase in the parameters in order to see if these were clinically useful.

RESULTS

A total of 80 patients, 20 per group, were included. The sBP, dBP, and MAP were significantly raised at the 2, 5, 8 and 10 minutes measurements in the S(+)K group compared to the rest of the groups (P<.05), as well as HR in the 2, 5, 8, 10 and 15 minute measurements in the S(+)K compared to the rest of the groups (P<.05). Sensitivity and specificity were high, and significant in the S(+)K group from minute 2 to minute 8 compared with the placebo group, as well as percentage points differences in the same interval. There were significant differences in the incidence of sedation-hypnosis, nystagmus and dizziness, which were more frequent in the S(+)K group. There were no differences in the incidence of metallic taste, perioral and facial paresthesias or tinnitus. The effects in the S(+)K group always occurred before minute 5 after drug injection.

CONCLUSION

Both lidocaine an adrenaline at the scheduled doses showed low sensitivity and specificity as a simulated iv epidural test dose. S(+)-ketamine could be a feasible marker after accidental iv injection during epidural anaesthesia or analgesia.

Air versus saline in the loss of resistance technique for identification of the epidural space

BACKGROUND

The success of epidural anaesthesia depends on correct identification of the epidural space. For several decades, the decision of whether to use air or physiological saline during the loss of resistance technique for identification of the epidural space has been governed by the personal experience of the anaesthesiologist. Epidural block remains one of the main regional anaesthesia techniques. It is used for surgical anaesthesia, obstetrical analgesia, postoperative analgesia and treatment of chronic pain and as a complement to general anaesthesia. The sensation felt by the anaesthesiologist from the syringe plunger with loss of resistance is different when air is compared with saline (fluid). Frequently fluid allows a rapid change from resistance to non-resistance and increased movement of the plunger. However, the ideal technique for identification of the epidural space remains unclear.

OBJECTIVES

• To evaluate the efficacy and safety of both air and saline in the loss of resistance technique for identification of the epidural space.• To evaluate complications related to the air or saline injected.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 9), MEDLINE, EMBASE and the Latin American and Caribbean Health Science Information Database (LILACS) (from inception to September 2013). We applied no language restrictions. The date of the most recent search was 7 September 2013.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-randomized controlled trials (quasi-RCTs) on air and saline in the loss of resistance technique for identification of the epidural space.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

We included in the review seven studies with a total of 852 participants. The methodological quality of the included studies was generally ranked as showing low risk of bias in most domains, with the exception of one study, which did not mask participants. We were able to include data from 838 participants in the meta-analysis. We found no statistically significant differences between participants receiving air and those given saline in any of the outcomes evaluated: inability to locate the epidural space (three trials, 619 participants) (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.33 to 2.31, low-quality evidence); accidental intravascular catheter placement (two trials, 223 participants) (RR 0.90, 95% CI 0.33 to 2.45, low-quality evidence); accidental subarachnoid catheter placement (four trials, 682 participants) (RR 2.95, 95% CI 0.12 to 71.90, low-quality evidence); combined spinal epidural failure (two trials, 400 participants) (RR 0.98, 95% CI 0.44 to 2.18, low-quality evidence); unblocked segments (five studies, 423 participants) (RR 1.66, 95% CI 0.72 to 3.85); and pain measured by VAS (two studies, 395 participants) (mean difference (MD) -0.09, 95% CI -0.37 to 0.18). With regard to adverse effects, we found no statistically significant differences between participants receiving air and those given saline in the occurrence of paraesthesias (three trials, 572 participants) (RR 0.89, 95% CI 0.69 to 1.15); difficulty in advancing the catheter (two trials, 227 participants) (RR 0.91, 95% CI 0.32 to 2.56); catheter replacement (two trials, 501 participants) (RR 0.69, 95% CI 0.26 to 1.83); and postdural puncture headache (one trial, 110 participants) (RR 0.83, 95% CI 0.12 to 5.71).

AUTHORS' CONCLUSIONS

Low-quality evidence shows that results do not differ between air and saline in terms of the loss of resistance technique for identification of the epidural space and reduction of complications. Applicability might be compromised, as most of the results described in this review were obtained from parturient patients. This review underlines the need to conduct well-designed trials in this field. 

Epidural catheter design: history, innovations, and clinical implications

Epidural catheters have evolved during the past several decades, as clinicians and manufacturers have sought to influence the quality of analgesia and anesthesia and reduce the incidence of catheter-related complications. This evolution has allowed a transformation from single-shot to continuous-infusion techniques and resulted in easier passage into the epidural space, more extensive medication distribution, and ultimately, improved patient satisfaction. Particular catheter features, including the materials used, tip design, and orifice number and arrangement, have been associated with specific outcomes and provide direction for future development.

Incidence and predictors of immediate complications following perioperative non-obstetric epidural punctures

Background

Epidural Anesthesia (EA) is a well-established procedure. The aim of the present study was to evaluate the incidence of immediate complications following epidural puncture, such as sanguineous puncture, accidental dural perforation, unsuccessful catheter placement or insufficient analgesia and to identify patient and maneuver related risk factors.

Methods

A total of 7958 non-obstetrical EA were analyzed. The risk of each complication was calculated according to the preconditions and the level of puncture. For probabilistic evaluation we used a logistic regression model with forward selection.

Results

The risk of sanguineous puncture (n = 247, 3.1%) increases with both the patient’s age (P = 0.013) and the more caudal the approach (P < 0.01). Dural perforation (n = 123, 1.6%) was found to be influenced only by advanced age (P = 0.019). Unsuccessful catheter placement (n = 68, 0.94%) occurred more often in smaller individuals (P < 0.001) and at lower lumbar sites (P < 0.01). Amongst all cases with successful catheter placement a (partial) insufficient analgesia was found in 692 cases (8.8%). This risk of insufficient analgesia decreased with patient’s age (P <0 .01), being least likely for punctures of the lower thoracic spine (P < 0.001).

Conclusions

Compared to more cranial levels, EA of the lower spine is associated with an increased risk of sanguineous and unsuccessful puncture. Insufficient analgesia more often accompanies high thoracic and low lumbar approaches. The risk of a sanguineous puncture increases in elderly patients. Gender, weight and body mass index seem to have no influence on the investigated complications.

Soft catheters reduce the risk of intravascular cannulation during epidural block--a retrospective analysis of 1,117 cases in a medical center

A wet or bloody tap is an inevitable complication while performing epidural block. The influence of different catheters on the incidence of intravascular cannulation during epidural catheterization has not been reported. We observed an initial, relatively different incidence of intravascular cannulation during the placement of different sorts of epidural catheter; hence, a retrospective review was conducted to explore the possible association. We reviewed 1-year interval anesthetic records of 1117 patients who had undergone epidural anesthesia or received patient-controlled epidural analgesia. Epidural catheter placement was performed by a loss of resistance technique with an 18-G Tuohy needle in lateral position. Patients were divided into two groups according to the different types of epidural catheters used (Perifix One, n=590; Perifix Standard, n=527). Primary outcome measurement was the incidence of intravascular injection. Other analyzed outcomes included dura puncture, failure rate, and low back pain. The incidence of epiduralintravascular cannulation was significantly lower using the Perifix One catheter (1.5%; 9/590) than using the Perifix Standard (4.6%; 24/527), p=0.003. The dura puncture rate did not differ significantly between the Perifix One (1.9%; 11/590) and the Perifix Standard (2.5%; 13/527), p=0.49. Failure rates and low back pain incidence were also comparable between the two groups. Application of the soft epidural catheter (Perifix One) may reduce the incidence of epidural intravascular cannulation. We suggest the use of Perifix One catheter instead of Perifix Standard catheter in daily practice.

Incidence of intravascular insertion in thoracic epidural catheterization by using real time fluoroscopy

BACKGROUND

Epidural analgesia is commonly used to provide several types of pain relief. Although this technique has been widely used with many advantages, currently the complications appear to be increasing. Especially, inadvertent intravascular cannulation and intravascular local anesthetic administration can lead to fatal consequences.

METHODS

Data was collected on 296 patients undergoing elective thoracic or abdominal surgery. Two detection methods were utilized to confirm the epidural intravascular cannulation; flashback and aspiration of indwelling catheter, and injection of a contrast agent through the catheter under fluoroscopy were used to guide the placement of the catheter and to examine the intravascular cannulation.

RESULTS

Epidural intravascular cannulation was reported in 4 out of 296 cases (1.4%), and 1 patient underwent subdural cannulation. Among the 4 cases of epidural intravascular cannulation, two were confirmed by the flashback and aspiration methods, while the remaining cases were only detected by real time fluoroscopy.

CONCLUSIONS

In this study, inadvertent epidural intravascular cannulation occurred by as much as 1.4% of thoracic epidural catheterization. Utilizing real time fluoroscopy in addition to flashback and aspiration can enhance the sensitivity of detection.

Effects of predistention with normal saline containing adrenaline on blood-vessel injury during epidural catheter placement

This study investigated the effects of predistention with normal saline containing adrenaline on vascular plexus injury during epidural catheter placement. Three hundred parturients undergoing caesarean sections were randomly divided into three groups. Group I (n = 102) received an epidural injection with 5 ml normal saline; group II (n = 93) received 5 ml normal saline containing adrenaline (5 μg/ml); group III (n = 100) received direct epidural catheter placement. Five women were excluded from the analysis for technical reasons. The incidence of bloody fluid in the epidural needle was significantly lower in groups I and II compared with group III (eight [7.8%] and seven [7.5%] versus 17 [17.0%], respectively). There were no significant differences in the incidence of bloody fluid in the epidural catheter or in the incidence of intravascular epidural catheter placement between the three groups. Predistention with 5 ml normal saline before catheter insertion reduced the incidence of blood-vessel injury during epidural catheter placement, but adrenaline provided no additional protective effects.

What's new in obstetric anesthesia?

The current article covers some of the major themes that emerged in 2009 in the fields of obstetric anesthesiology, obstetrics, and perinatology, with a special emphasis on the implications for the obstetric anesthesiologist.