Risk factors for epidural anesthesia blockade failure in cesarean section: a retrospective study

doi:10.21203/rs.3.rs-3137844/v1

Download PDF

Research Article

Risk factors for epidural anesthesia blockade failure in cesarean section: a retrospective study

https://doi.org/10.21203/rs.3.rs-3137844/v1

This work is licensed under a CC BY 4.0 License

Journal Publication

published 06 Oct, 2023

Read the published version in BMC Anesthesiology →

You are reading this latest preprint version

Background:

Epidural anesthesia (EA) is the preferred regional anesthesia technique in pregnant women who require cesarean section for delivery. Failure of EA requires additional sedation or convert it into general anesthesia (GA). It may be hazardous during sedation or GA conversion due to a potentially difficult airway. Therefore, this retrospective study aimed to determine the risk factors for epidural failure during cesarean section anesthesia.

Methods:

We retrospectively analyzed parturients who underwent cesarean section under EA and catheterization at Chang Gung Memorial Hospital in Taiwan between January 1 and December 31, 2018. Patient data were collected from medical records. EA failure was defined as the administration of any intravenous anesthetic at any time during the cesarean section, converting it into GA or even tube GA.

Results:

A total of 534 parturients who underwent cesarean section were recruited for this study. Of these, 94 (17.6%) parturients experienced failure of EA during the cesarean section. Compared to the patients with successful EA, those with EA failure were younger (33.0 years vs. 34.7 years) and have received EA previously (60.6% vs. 37%), were parous (72.3% vs. 55%), and had a shorter waiting time (14.9 mins vs. 16.5 mins) (p < 0.05). Younger age (OR 0.91, 95% CI 0.86–0.95), history of epidural analgesia (OR 2.61, 95% CI 1.38–4.94), and shorter waiting time (OR 0.91, 95% CI 0.87–0.97) were estimated to be significantly associated with a higher risk of epidural anesthesia failure.

Conclusion:

The retrospective study found that parturients with younger age, previous epidural catheterization history, and inadequate waiting time may have a higher risk of EA failure. Previous epidural catheterization increases the risk of EA failure by 2.6-folds compared to those with no catheterization history.

Epidural failure

previous epidural history

risk factors

cesarean section

Epidural anesthesia (EA) and spinal anesthesia (SA) are the regional anesthesia techniques preferred over general anesthesia (GA) in pregnant women who require cesarean section for delivery because of the potentially difficult airway management and systemic anesthetic effects on the fetus and uterine tone under general anesthesia [1, 2]. In comparison to SA, additional local anesthetic with EA can be administered to prolong anesthesia duration, and the catheter is also a good access point for post-operative pain control, although a higher failure rate is reported [3] during the conversion of labor analgesia into anesthesia. The average failure rate ranges from 13.4–22.1% in cesarean sections under EA [4, 5] compared to 0.9–2.5% under SA [3, 6].

Several factors are associated with an increased risk of epidural failure, including patient characteristics and procedural aspects. High body mass index (BMI), prolonged labors, breakthrough pain during labor analgesia, urgency in cesarean sections, an increasing number of top-ups, and maternal height are considered risk factors in patients [7, 8]. Procedure-related risks include non-obstetric anesthesiologists, air for loss of resistance, and catheter flexibility [9–11]. Failure of EA requires additional intravenous anesthesia for sedation to achieve an adequate level of anesthesia, perform spinal anesthesia, or even convert it into general anesthesia. It may be hazardous during sedation or GA conversion due to a potentially difficult airway. Therefore, identifying risk factors leading to epidural failure is necessary.

This retrospective study aimed to identify the risk factors associated with the failure of surgical EA directly after a routine epidural procedure and the proper waiting time in the operating room without conversion from labor analgesia.

Patients

This study was approved by the Institutional Review Board of Chang Gung Memorial Hospital, Taoyuan, Taiwan (registration number:201901851B0). We retrospectively analyzed parturients who were admitted for cesarean section at Chang Gung Memorial Hospital in Taiwan between January 1 and December 31, 2018. Parturients who underwent cesarean section under EA and catheterization in the operating room were included in the study. Parturients were excluded if they had different epidural anesthetics other than routine epidural anesthetic mixtures, EA by trainees with experience of lumbar epidural analgesia or anesthesia less than 50 times, short periods between complete anesthesia and surgical incision (less than 10 minutes), uncertain previous neuroaxial anesthesia or analgesia history, or history of spine surgery or abnormalities. Patients with known dural punctures before catheterization were also excluded. A total of 534 parturients were recruited for this study as shown in Fig. 1.

Study protocol

Routine EA and EA with cauterization were performed using an 18-gauge Tuohy needle and a 20-gauge catheter (Perifix® B. Braun Melsungen AG, Melsungen, Germany). The patient was placed in the right-lateral position during the procedure. After loss of resistance (whether by air or saline), a 20-gauge catheter was placed into the epidural space, and a 3–5 mL testing dose was injected via the catheter. Thereafter, signs of intravascular injection and intrathecal injection were checked, and if no signs of intravascular injection or intrathecal injection were observed, the catheter was fixed with adhesive tape. A total 15–24 mL of anesthetic mixture (lidocaine 400 mg, fentanyl 100 mcg, sodium bicarbonate 2.8 g and epinephrine 0.1 mg), including the testing dose, was administered into the epidural space via the catheter. Anesthesia was induced after anesthetic administration and the time was recorded automatically by a hospital recording system. After preparation for the cesarean section, surgeons would start surgery after testing for pinprick sensation. In case of inadequate anesthesia level or block failure, whether to proceed with EA or switch to general anesthesia was decided based on the anesthesiologist’s expertise.

Data collection and variable definition

Patient data were collected from medical records. Demographic characteristics including age, height, weight, BMI, history of previous epidural anesthesia or analgesia, puncture site, loss of resistance skill, procedure performance (visiting staff or experienced trainees), anesthetic mixture volume administered previously, emergency or scheduled cesarean section, rupture of membranes before surgery, and American Society of Anesthesiologists physical status were collected. EA failure was defined as the administration of any intravenous anesthetic at any time during the cesarean section, converting it into GA or even tube GA. The anesthetics included thiamylal, propofol, ketamine, midazolam, and fentanyl. The duration between EA and surgical incision was recorded.

Statistical analysis

The baseline characteristics of the subjects in the two groups (i.e., failure of anesthesia vs. non-failure and previous epidural analgesia vs. none) were compared using an independent sample t-test for continuous variables or a chi-square test for categorical variables. The association between clinical characteristics and the risk of anesthesia failure was investigated using univariate and multivariable logistic regression analyses. Factors potentially correlated with the risk of anesthesia failure were initially screened using a series of univariate logistic regression models. For factors with a significance level of less than 0.2 in the univariate analyses were further analyzed using a multivariable model [12]. The survival rate from time to intravenous anesthetics supplementation was estimated using the Kaplan-Meier method, along with the log-rank test to compare the groups (previous epidural analgesia vs. none). All tests were 2-tailed and p < 0.05 was considered statistically significant. Data were analyzed using SPSS version 25 (IBM SPSS Inc, Chicago, Illinois, USA).

Baseline characteristics

In total, 722 parturients were initially recruited for this study. After excluding 188 patients, 534 parturients were included in the study (Fig. 1). Of these, 94 (17.6%) parturients experienced failure of EA during the cesarean section (Table 1). The mean age was calculated to be 34.4 years. A total of 220 parturients (41.2%) had previously received subjects received epidural EA, and the most punctured site was L3-4 (n = 442, 82.8%). Most of the loss-of-resistance methods used air (n = 457, 85.6%). A total of 310 patients (58.1%) were parous. The mean waiting time was 16.2 minutes. Compared to the patients with successful EA, those with EA failure were younger (33.0 years vs. 34.7 years) and more likely to have received EA previously (60.6% vs. 37%), were parous (72.3% vs. 55%), and had a shorter waiting time (14.9 mins vs. 16.5 mins) (p < 0.05).

Table 1

Baseline characteristics of study subjects according to epidural failure
		Epidural failure
Variable	Total (n = 534)	No (Success) (n = 440)	Yes (Failure) (n = 94)	P value
Age, years	34.4 ± 4.9	34.7 ± 4.8	33.0 ± 5.3	0.003
Height, cm	159.1 ± 5.8	159.1 ± 6.0	159.0 ± 4.7	0.841
Weight, kg	71.2 ± 12.1	71.6 ± 12.1	69.4 ± 11.9	0.106
Body mass index, kg/m²	28.1 ± 4.6	28.3 ± 4.6	27.4 ± 4.3	0.091
Previous epidural analgesia	220 (41.2)	163 (37.0)	57 (60.6)	< 0.001
Puncture site				0.314
L2-3	69 (12.9)	54 (12.3)	15 (16.0)
L3-4	442 (82.8)	369 (83.9)	73 (77.7)
L4-5	23 (4.3)	17 (3.9)	6 (6.4)
Loss of resistance methods				0.885
Air	457 (85.6)	377 (85.7)	80 (85.1)
Saline	77 (14.4)	63 (14.3)	14 (14.9)
Catheter depth, cm	5.3 ± 0.7	5.24 ± 0.65	5.31 ± 0.67	0.393
Experience of anesthesia provider				0.725
Resident	444 (83.1)	367 (83.4)	77 (81.9)
Obstetric anesthesiologist	90 (16.9)	73 (16.6)	17 (18.1)
Emergency surgery	217 (40.6)	185 (42.0)	32 (34.0)	0.152
Rupture of membrane	76 (14.2)	65 (14.8)	11 (11.7)	0.439
Parity				0.002
Nulliparous	224 (41.9)	198 (45.0)	26 (27.7)
Parous	310 (58.1)	242 (55.0)	68 (72.3)
Waiting time	16.2 ± 4.7	16.5 ± 4.7	14.9 ± 4.7	0.002
Data were presented as frequency (percentage) or mean ± standard deviation.

Associated factors for failure of analgesia

The univariate logistic regression models showed that the following factors were potentially correlated with the risk of epidural anesthesia failure: younger age, lower BMI, previous EA administration, emergency surgery, being parous, and shorter waiting time. A multivariable model was used to rule out correlations that may affect risk factors. The multivariable model demonstrated that younger age (odds ratio [OR] 0.91, 95% confidence interval [CI] 0.86–0.95), previous EA administration (OR 2.61, 95% CI 1.38–4.94), and shorter waiting time (OR 0.91, 95% CI 0.87–0.97) were significantly associated with a higher likelihood of EA failure (Table 2). The time to epidural failure among participants who previously received EA and those who did not is illustrated in Fig. 2. Patients with previous EA administration had a greater risk of epidural failure in a shorter time period.

Table 2

The associated factors of epidural failure
	Univariate analysis		Multivariable analysis
Variable	Crude OR (95% CI)	P value	Adjusted OR (95% CI)	P value
Age, years	0.94 (0.89–0.98)	0.004	0.91 (0.86–0.95)	< 0.001
Body mass index, kg/m²	0.96 (0.91–1.01)	0.092	0.96 (0.90–1.01)	0.112
Previous epidural analgesia	2.62 (1.66–4.13)	< 0.001	2.61 (1.38–4.94)	0.003
Puncture site
L2-3	1.00
L3-4	0.71 (0.38–1.33)	0.287
L4-5	1.27 (0.43–3.79)	0.667
Loss of resistance methods (Saline vs. Air)	1.05 (0.56–1.96)	0.885
Catheter depth, cm	1.16 (0.82–1.64)	0.392
Experience of anesthesia provider (Obstetric anesthesiologist vs. Resident)	1.11 (0.62–1.99)	0.725
Emergency surgery	0.71 (0.45–1.14)	0.153	0.83 (0.50–1.35)	0.446
Rupture of membrane	0.76 (0.39–1.51)	0.440
Parity (Parous vs. Nulliparous)	2.14 (1.31–3.49)	0.002	1.44 (0.73–2.84)	0.289
Waiting time	0.92 (0.87–0.97)	0.002	0.91 (0.87–0.97)	0.002
Abbreviations: OR, odds ratio; CI, confidence interval.

Characteristics of patients with and without previous EA administration

Based on the aforementioned analyses, previous EA administration appeared to be a dominant factor responsible for analgesia failure. Therefore, the clinical characteristics of patients with and without previous EA administration were compared. The results showed that the patients with previous EA administration were older (35.4 years vs. 33.7 years), less likely to have emergent surgery (31.4% vs. 47.1%), had a lower incidence of rupture of membrane (9.1% vs. 17.8%), and were more likely to be parous (95.9% vs. 31.5%), compared to those without previous EA administration (p < 0.05) (Table 3).

Table 3

Baseline characteristics of study subjects according to previous epidural analgesia
Variable	Previous epidural analgesia
Variable	Yes (n = 220)	No (n = 314)	P value
Age, years	35.4 ± 4.4	33.7 ± 5.2	< 0.001
Height, cm	159.4 ± 5.2	158.9 ± 6.2	0.425
Weight, kg	71.2 ± 11.6	71.3 ± 12.4	0.907
Body mass index, kg/m²	28.0 ± 4.0	28.2 ± 4.9	0.508
Puncture site			0.089
L2-3	33 (15.0)	36 (11.5)
L3-4	182 (82.7)	260 (82.8)
L4-5	5 (2.3)	18 (5.7)
Loss of resistance methods			0.412
Air	185 (84.1)	272 (86.6)
Saline	35 (15.9)	42 (13.4)
Catheter depth, cm	5.23 ± 0.65	5.28 ± 0.66	0.357
Experience of anesthesia provider			0.357
Resident	179 (81.4)	265 (84.4)
Obstetric anesthesiologist	41 (18.6)	49 (15.6)
Emergency surgery	69 (31.4)	148 (47.1)	< 0.001
Rupture of membrane	20 (9.1)	56 (17.8)	0.004
Parity			< 0.001
Nulliparous	9 (4.1)	215 (68.5)
Parous	211 (95.9)	99 (31.5)
Waiting time	16.3 ± 4.9	16.2 ± 4.6	0.874
epidural failure	57 (25.9)	37 (11.8)	< 0.001
Data were presented as frequency (percentage) or mean ± standard deviation.

In this study, we examined the risk factors that may cause failure in the conversion of labor analgesia to anesthesia for cesarean section reported in previous studies, such as those performed by trainees, parturients with high BMI, and using air for the loss of resistance test [13, 14]. However, no significant differences were observed between groups. For epidural catheterization performed during the study period, all trainees who performed anesthesia had experience of EA, including cesarean section and labor analgesia for over 100 cases, which may explain the significant difference between trainees and visiting staff.

Previous studies have indicated that a higher BMI leads to both technical difficulty and failure of neuraxial anesthesia [15], whereas higher risks of extension failure to surgical anesthesia have been reported in obese parturients [16]. However, in this study, the number of parturients with a high BMI was small; only 5 parturients out of 539 had a body mass index ≥ 40 kg/m2, which is defined as morbid obesity. In contrast, due to the physical limitation of the epidural needle, which is only 8 cm in length, a patient with high BMI may experience epidural catheterization failure and be required to switch to spinal anesthesia, causing difficulties in tracing anesthesia records. Therefore, fewer parturients with high BMI were included in the present study.

Loss of resistance with air may increase the risk of epidural failure comparing with saline [17, 18]. It was mentioned that the air might affect spread of local anesthetic, resulting in an incomplete “patchy block”, leading to increased use of intraoperative intravenous anesthetics. Segal examined 929 labor anesthetics and reported no difference between air and saline when the preferred technique was used [19]. In this study, the failure rate with air was 18%, whereas it was 17% with saline, without any significant difference between the two. The loss of resistance skill with air is mainly used in Chang Gung Memorial Hospital, and repeated the tests with air are avoided in the protocol, which may have resulted in a slightly higher failure rate in the air group than that in the saline group; however, no significant difference was observed using the statistical analysis.

Parturients with previous epidural experience had a higher failure rate than those who received EA for the first time. A previous study has reported significant inflammatory changes and adhesions using the epidural scope in patients with a history of EA [20, 21]. Puncture of the flava ligament and epidural catheterization lead to congestion and adhesions in the epidural space, resulting in disturbance in the local anesthetic spread in the epidural space [22]. Traumatic changes such as fibrosis, congestion and hemorrhage may influence the local cephalic spread of local anesthetics, and worsen drug penetration, leading to top-up failure or an inadequate blockade. Repeated epidural anesthesia is associated with a higher risk of a unilateral block [23].

As mentioned in Fig. 2, the survival curve after epidural anesthetics administration was changed after 12 minutes, suggesting that the failure mainly resulted from inadequate waiting time for lidocaine-bicarbonate-epinephrine-fentanyl to reach surgical anesthesia at T7 level [24, 25]. The survival rate of parturients without epidural failure dropped much quicker within 12 minutes after anesthetic administration in parturients with previous EA administration or analgesia compared to those with no previous administration, indicating a difference between parturients with and without a history of previous EA or analgesia. Patients with a history of EA administration showed a higher failure rate for the same waiting time. Collectively with previous studies [19, 20], the cephalic spread of local anesthetic is slower in parturients with previous epidural experience, and it also affects drug penetration to nerve roots, leading to inadequate anesthesia during surgery; parturients need extra intravenous anesthetic administration to fulfil anesthesia needs and even require switching to GA.

Age also plays a role in epidural failure; younger patients may have a higher risk for epidural failure. Several studies have also reported younger age as a risk factor of epidural failure [9, 26]. We suggest that, because of the decrease in myelinated fibers with aging [27], it takes more time for local anesthetics to penetrate the nerve roots and achieve adequate anesthesia for a cesarean section. Further studies are required to evaluate these risk factors.

A limitation of this study is its retrospective design. Failure was defined as an inadequate block and the inability to perform a cesarean section without intravenous anesthetic administration; however, the record did not indicate if it was an inadequate block or if the parturient was administered a sedative due to nervousness. To avoid bias, the procedures should be carried out by obstetric anesthesiologists and the loss of resistance must be performed using saline or air. Further prospective studies with additional controlling factors are required.

The retrospective study found that paturients with previous epidural catheterization history, inadequate waiting time, and a younger age may have a higher risk of EA failure. Previous epidural catheterization increases the risk of EA failure by 2.6-folds compared to those with no catheterization history.

Epidural anesthesia

General anesthesia

Odds ratio

Confidence interval

Spinal anesthesia

BMI

Body mass index.

Conflict-of-interest statement: The authors declare that there are no conflicts of interests regarding the publication of this paper.

Acknowledgements

Not applicable.

Funding

No funding.

Availability of data and materials

All data generated or analyzed during this study are included in this published article.

Authors’ contributions

WHC designed and conceived the study, analyzed the data, and wrote the manuscript. WSC helped to conduct the study and draft the manuscript. LMH helped to design the study and to analyze the data. CCL designed and conducted the study, wrote the manuscript, and revised it for important intellectual content. All authors read and approved the final manuscript.

Ethics approval and consent to participate

This study was approved by the Institutional Review Board of Chang Gung Memorial Hospital, Taoyuan, Taiwan (registration number: 201901851B0). All procedures performed in the studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the Helsinki declaration and its later amendments or comparable ethical standards. The Institutional Review Board of Chang Gung Memorial Hospital waived the need for written informed consent from participants due to the non-interventional study design.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Djabatey EA, Barclay PM: Difficult and failed intubation in 3430 obstetric general anaesthetics. Anaesthesia 2009, 64(11):1168-1171.
Algert CS, Bowen JR, Giles WB, Knoblanche GE, Lain SJ, Roberts CL: Regional block versus general anaesthesia for caesarean section and neonatal outcomes: a population-based study. BMC Med 2009, 7:20.
Yoon HJ, Do SH, Yun YJ: Comparing epidural surgical anesthesia and spinal anesthesia following epidural labor analgesia for intrapartum cesarean section: a prospective randomized controlled trial. Korean J Anesthesiol 2017, 70(4):412-419.
Desai N, Gardner A, Carvalho B: Labor Epidural Analgesia to Cesarean Section Anesthetic Conversion Failure: A National Survey. Anesthesiol Res Pract 2019, 2019:6381792.
Ismail S, Chugtai S, Hussain A: Incidence of cesarean section and analysis of risk factors for failed conversion of labor epidural to surgical anesthesia: A prospective, observational study in a tertiary care center. J Anaesthesiol Clin Pharmacol 2015, 31(4):535-541.
Punchuklang W, Nivatpumin P, Jintadawong T: Total failure of spinal anesthesia for cesarean delivery, associated factors, and outcomes: A retrospective case-control study. Medicine (Baltimore) 2022, 101(27):e29813.
Halpern SH, Soliman A, Yee J, Angle P, Ioscovich A: Conversion of epidural labour analgesia to anaesthesia for Caesarean section: a prospective study of the incidence and determinants of failure. Br J Anaesth 2009, 102(2):240-243.
Lee S, Lew E, Lim Y, Sia AT: Failure of augmentation of labor epidural analgesia for intrapartum cesarean delivery: a retrospective review. Anesth Analg 2009, 108(1):252-254.
Bauer ME, Kountanis JA, Tsen LC, Greenfield ML, Mhyre JM: Risk factors for failed conversion of labor epidural analgesia to cesarean delivery anesthesia: a systematic review and meta-analysis of observational trials. Int J Obstet Anesth 2012, 21(4):294-309.
Mankowitz SK, Gonzalez Fiol A, Smiley R: Failure to Extend Epidural Labor Analgesia for Cesarean Delivery Anesthesia: A Focused Review. Anesth Analg 2016, 123(5):1174-1180.
Guasch E, Iannuccelli F, Brogly N, Gilsanz F: Failed epidural for labor: what now? Minerva Anestesiol 2017, 83(11):1207-1213.
Maldonado G, Greenland S: Simulation study of confounder-selection strategies. Am J Epidemiol 1993, 138(11):923-936.
Hermanides J, Hollmann MW, Stevens MF, Lirk P: Failed epidural: causes and management. Br J Anaesth 2012, 109(2):144-154.
Agaram R, Douglas MJ, McTaggart RA, Gunka V: Inadequate pain relief with labor epidurals: a multivariate analysis of associated factors. Int J Obstet Anesth 2009, 18(1):10-14.
Kula AO, Riess ML, Ellinas EH: Increasing body mass index predicts increasing difficulty, failure rate, and time to discovery of failure of epidural anesthesia in laboring patients. J Clin Anesth 2017, 37:154-158.
Eley VA, Chin A, Tham I, Poh J, Aujla P, Glasgow E, Brown H, Steele K, Webb L, van Zundert A: Epidural extension failure in obese women is comparable to that of non-obese women. Acta Anaesthesiol Scand 2018, 62(6):839-847.
Beilin Y, Arnold I, Telfeyan C, Bernstein HH, Hossain S: Quality of analgesia when air versus saline is used for identification of the epidural space in the parturient. Reg Anesth Pain Med 2000, 25(6):596-599.
Shenouda PE, Cunningham BJ: Assessing the superiority of saline versus air for use in the epidural loss of resistance technique: a literature review. Reg Anesth Pain Med 2003, 28(1):48-53.
Segal S, Arendt KW: A retrospective effectiveness study of loss of resistance to air or saline for identification of the epidural space. Anesth Analg 2010, 110(2):558-563.
Igarashi T, Hirabayashi Y, Shimizu R, Mitsuhata H, Saitoh K, Fukuda H, Konishi A, Asahara H: Inflammatory changes after extradural anaesthesia may affect the spread of local anaesthetic within the extradural space. Br J Anaesth 1996, 77(3):347-351.
Shimada N, Igarashi T, Murai K, Hara T, Kuramochi T, Takeuchi M: Adhesions in the epidural space caused by frequent epidural blocks. JA Clin Rep 2017, 3(1):57.
Kitamura A, Sakamoto A, Aoki S, Ogura A, Kawahara T, Inoue T, Ogawa R: Epiduroscopic changes in patients undergoing single and repeated epidural injections. Anesth Analg 1996, 82(1):88-90.
Withington DE, Weeks SK: Repeat epidural analgesia and unilateral block. Can J Anaesth 1994, 41(7):568-571.
Goring-Morris J, Russell IF: A randomised comparison of 0.5% bupivacaine with a lidocaine/epinephrine/fentanyl mixture for epidural top-up for emergency caesarean section after "low dose" epidural for labour. Int J Obstet Anesth 2006, 15(2):109-114.
Hillyard SG, Bate TE, Corcoran TB, Paech MJ, O'Sullivan G: Extending epidural analgesia for emergency Caesarean section: a meta-analysis. Br J Anaesth 2011, 107(5):668-678.
Grap SM, Patel GR, Huang J, Vaida SJ: Risk factors for labor epidural conversion failure requiring general anesthesia for cesarean delivery. J Anaesthesiol Clin Pharmacol 2022, 38(1):118-123.
Visser WA, Lee RA, Gielen MJ: Factors affecting the distribution of neural blockade by local anesthetics in epidural anesthesia and a comparison of lumbar versus thoracic epidural anesthesia. Anesth Analg 2008, 107(2):708-721.

No competing interests reported.

Download PDF

Journal Publication

published 06 Oct, 2023

Read the published version in BMC Anesthesiology →

Editorial decision: Major revision
20 Aug, 2023
Reviews received at journal
18 Aug, 2023
Reviews received at journal
07 Aug, 2023
Reviewers agreed at journal
26 Jul, 2023
Reviewers invited by journal
23 Jul, 2023
Editor assigned by journal
20 Jul, 2023
Editor invited by journal
15 Jul, 2023
Submission checks completed at journal
15 Jul, 2023
First submitted to journal
04 Jul, 2023

You are reading this latest preprint version

Risk factors for epidural anesthesia blockade failure in cesarean section: a retrospective study

Status:

Journal Publication

Version 1

Abstract

Background:

Methods:

Results:

Conclusion:

Figures

Background

Materials and methods

Patients

Study protocol

Data collection and variable definition

Statistical analysis

Results

Baseline characteristics

Associated factors for failure of analgesia

Characteristics of patients with and without previous EA administration

Discussion

Conclusions

Abbreviations

Declarations

References

Additional Declarations

Status:

Journal Publication

Version 1