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  Brief Report Failure of Augmentation of Labor Epidural Analgesia for Intrapartum Cesarean Delivery: A Retrospective Review  Shuying Lee, MMedEileen Lew, MMedYvonne Lim, MMedAlex T. Sia, MMed In this study, we aimed to identify the incidence and predictive factors associatedwith failed labor epidural augmentation for cesarean delivery. Data of parturients,who had received neuraxial labor analgesia and who subsequently requiredintrapartum cesarean delivery during an 18-mo period, were retrospectivelystudied. Predictors associated with failure of extension of epidural analgesia in thepresence of adequate time for onset of epidural anesthesia were identified byunivariate logistic regression. Of the 1025 parturients, 1.7% had failed epiduralextension. Predictors of failed epidural anesthesia included initiation of laboranalgesia with plain epidural technique (compared to combined spinal-epidural)( P    0.001),   2 episodes of breakthrough pain during labor ( P    0.001) andprolonged duration of neuraxial labor analgesia ( P  0.02). (Anesth Analg 2009;108:252–4) E pidural analgesia not only provides effective laboranalgesia but may be extended to provide anesthesiafor intrapartum cesarean delivery by administeringhigh concentration local anesthetic solutions. Whenfailure of block extension occurs, the alternative in-cludes the administration of general anesthesia orrepeat neuraxial blockade. Unanticipated changes inanesthesia can lead to serious morbidity and mortal-ity. 1,2 Hence, it is important to identify the factorsassociated with epidural failure. METHODS With institutional research board approval, a data- base was established to capture information pertain-ing to all laboring parturients who requestedneuraxial pain relief. We identified those with intra-partum epidural catheters who subsequently requiredcesarean delivery over an 18-mo period and retrievedthe following data: weight, height and parity; ASAphysical status; cervical dilation at initiation of neuraxial analgesia; visual analog scale (VAS) painscores; anesthesiologist seniority; neuraxial techniquedetails; duration of neuraxial labor analgesia; numberof breakthrough pain episodes requiring intrapartumepidural boluses and neonatal weight.Initiation of labor analgesia using either combinedspinal-epidural (CSE) or epidural analgesia wasguided by institutional guidelines. CSE analgesia wasinduced with intrathecal bupivacaine or ropivacaine2.0–2.5 mg and fentanyl 15–25   g. Epidural analgesia(Perifix  , B.Braun, Melsungen, Germany) was in-duced with bupivacaine 8–15 mL or ropivacaine1.25–2.50 mg/mL. Analgesia was maintained for bothtechniques with either: 1) 6–12 mL/h continuousinfusion of ropivacaine or bupivacaine (1.0–1.5mg/mL), plus fentanyl 2   g/mL initiated within 15min of analgesia induction, or 2) patient-controlledepidural analgesia (PCEA) with the same solutions: bolus 5 mL, lockout interval 10 min, total dose limit 20mL/h and basal infusion rate 0–10 mL/h.After induction of labor neuraxial blockade, a dedi-cated midwife recorded hourly data including VASpain score, dermatomal block height and Bromagescore. 3 Breakthrough pain, defined as labor pain of VAS   3 cm, was treated with 5–15 mL epidural boluses of lidocaine 15 mg/mL, bupivacaine 2.0–2.5mg/mL or ropivacaine 2 mg/mL, with or withoutfentanyl (  100   g).As per institutional protocol, parturients with intra-partum epidural catheters who subsequently requiredcesarean delivery received a standard 20 mL epidural bolus top-up of lidocaine 15 mg/mL with sodium bicarbonate 1 mEq/10 mL, epinephrine 5   g/mL andfentanyl 50–100   g. Failure of extension of epidurallabor analgesia, defined as inadequate neuraxial blockade for cesarean delivery in the presence of adequate time for onset of epidural anesthesia, wasnoted, as well as the apparent reason(s) for failure andtime since initiation of epidural extension.Parturients were classified as “success” or “failure,”depending on the success of epidural augmentation.All parturients who had catheter replacement during From the Department of Women’s Anesthesia, KK Women’s andChildren’s Hospital, Singapore.Accepted for publication September 25, 2008.Reprints will not be available from the author.Address correspondence to Eileen Lew, MMed, Department of Women’s Anesthesia, KK Women’s and Children’s Hospital, 100,Bukit Timah Rd., Singapore 229899, Republic of Singapore. Addresse-mail to © 2008 International Anesthesia Research Society DOI: 10.1213/ane.0b013e3181900260 Vol. 108, No. 1, January 2009 252  labor were classified according to the latter technique.We excluded cases in which the epidural injection-skin incision interval was   15 min and epiduralanesthesia was contraindicated and not attempted(e.g., maternal anxiety, maternal hemorrhage), andthose with inadvertent dural puncture. The successand failure groups were compared by univariate lo-gistic regression for each variable and their odds ratiocalculated using SPSS (Windows version 13, Chicago,IL).  P  0.05 was significant. RESULTS During the study period, 5483 parturients re-quested labor neuraxial analgesia: 658 epidural and4825 CSE. Of the 1033 laboring parturients who  Table 1.  Demographic, Neuraxial Block and Labor Progress Data: Epidural Anesthesia Success Versus Failure  VariablesOutcome of epiduralaugmentationOdds ratio(95% CI)  P  Success( n  1008)Failure( n  17) Baseline patient characteristicsWeight (kg) 73  31 74  14 1.00 (0.99–1.01) 0.88Height (cm) 156  10 157  5 1.02 (0.95–1.09) 0.66ASA PSI 828 (82) 14 (82)II 179 (18) 3 (18)III 1 (0) 0 (0) 0.99 (0.28–3.49) 0.99ParityNulliparous 819 (81) 14 (82)Parous 189 (19) 3 (18) 1.08 (0.31–3.79) 0.91Onset of laborSpontaneous 396 (39) 7 (41) 0.92 (0.35–2.45) 0.87Prostin E2 induction 389 (39) 9 (53) 0.56 (0.21–1.46) 0.24AROM 288 (29) 5 (29) 0.96 (0.34–2.75) 0.94Cervical dilatation at initiation of analgesia (cm) 3 (2–4) 3 (2–4) 1.03 (0.68–1.54) 0.90Neuraxial block dataExperience of anesthesia providerResidents 210 (21) 5 (29) 2.82 (0.75–10.61) 0.13Clinical associates 171 (17) 4 (24) 2.77 (0.69–11.21)Fellows 152 (15) 4 (24) 3.12 (0.77–12.62)Consultants 474 (47) 4 (24)Neuraxial block techniqueEpidural 113 (11) 7 (41) 0.001CSE 895 (89) 10 (59) 5.54 (2.07–14.85)Approach to blockMidline 989 (98) 16 (94) 0.26Paramedian 19 (2) 1 (6) 3.25 (0.41–25.80)Position of patient during procedureLateral 500 (50) 11 (65) 0.22Sitting 508 (50) 6 (35) 0.54 (0.20–1.46)Loss of resistance techniqueAir 324 (32) 6 (35) 0.78Saline 684 (68) 11 (65) 0.87 (0.32–2.37)Time taken for procedure (min) 6  4 7  5 1.04 (0.94–1.15) 0.47Depth of epidural space from skin (cm) 5  1 5  1 0.98 (0.64–1.51) 0.94Length of catheter in space (cm) 4  1 4  1 0.85 (0.47–1.52) 0.57Data pertaining to labor progressVAS (cm)Preblock 7 (4–10) 7 (3–10) 0.96 (0.81–1.15) 0.68Postblock 0 (0–1) 1 (0–3) 1.18 (0.91–1.53) 0.21No. of breakthrough pain episodes0–1 912 (91) 10 (59)2–5 96 (10) 7 (41) 6.65 (2.48–17.87)   0.001Highest VAS during epidural infusion 1 (0–2) 2 (0–3) 1.08 (0.90–1.30) 0.40Duration of neuraxial labor analgesia (h) 8  6 12  6 1.06 (1.01–1.11) 0.02Patient satisfaction (%) a 88  11 86  14 0.99 (0.95–1.03) 0.47Neonatal weight (g) 3189  487 3133  409 1.00 (0.10–1.00) 0.64 Data are expressed as mean  SD , median (range) or   n  (%).VAS    visual analogue scale; AROM    artificial rupture of membranes; CSE    combined spinal-epidural; CI    confidence interval; PS    physical status; ASA    American Society of Anesthesiologists. a Patients asked to express satisfaction with labor analgesia as percent of 100. Vol. 108, No. 1, January 2009  © 2008 International Anesthesia Research Society  253  needed intrapartum cesarean delivery, we excluded 8:time from epidural top-up to start of surgery  15 min(3); nonreassuring fetal status (3); maternal anxiety (2).Of the remaining 1025 parturients, 17 (1.7%) hadfailed epidural block augmentation and were admin-istered general anesthesia before delivery of baby: before surgical incision (8) and after surgical inci-sion, but before uterine incision (9). The mainreasons for conversion to general were sensory block height below T 5 , poor quality, and patchy block. Repeat neuraxial anesthesia was not used.Table 1 shows the comparison between parturientswho had successful augmentation of epidural anesthe-sia and those with catheter failures. The variablesassociated with catheter failure were duration of epi-dural catheter  in situ , epidural versus CSE analgesiafor initiation of labor analgesia, and number of intra-partum breakthrough pain episodes.A disproportionate number of parturients main-tained labor analgesia via an infusion (894) versusthose receiving PCEA (131). All failure patients re-ceived the infusion regime. The incidence of break-through pain episodes was similar in “infusion” (10%)and “PCEA” groups (11%).Twenty-one of 1025 catheters were replaced intra-partum before presenting for cesarean delivery: 8epidural and 13 CSE. All replaced catheters weresuccessfully extended for anesthesia. DISCUSSION The failure rate for epidural augmentation at ourinstitution was 1.7%. The failure rate reported in theliterature ranges from 0% to 38% 4–11 and the widediscrepancy could be due to varying definitions of failure. For example, some studies included cases inwhich epidural extension was not attempted. Thefrequent use of CSE analgesia and early replacementof “uncertain” catheters during labor analgesia, aswell as the experience of the anesthesia providers,may have also contributed to our low failure rate. Allfailure patients in this study were administered gen-eral anesthesia instead of repeat neuraxial blocks dueto concerns of time constraints and risk of reachingtoxic local anesthetic doses.The predictors of failed epidural catheter identifiedin this study are similar to those of other studies.Catheters inserted using a CSE technique were lesslikely to require replacement compared to an epiduraltechnique. 12–14 The attainment of freely flowing cere- brospinal fluid during the spinal component of CSEanalgesia strongly suggests optimal midline place-ment of the epidural Tuohy needle. This might explainthe increased incidence of successful epidural block-ade with CSE analgesia. The role of dural rent inenhancing the effect of local anesthetics depositedepidurally could also be a contributory factor. 15 Thestudy could not ascertain if any of the epiduralcatheters were inserted as a result of failed CSEanalgesia. Occurrence of more than one intrapartum breakthrough pain episode had been a consistentpredictor of failed epidural augmentation. 8,10 Dura-tion of labor, analgesia was significantly longer in thefailure cases. Epidural catheters  in situ  for prolongedperiods of time were at higher risk of migration anddislodgement, possibly accounting for higher failurerates.There are several limitations to our study. Becausethe study was retrospective, we could not control forvariations in analgesic and anesthetic techniques. Re-porting and selection could be biased. For instance,CSE analgesia might be preferred for multiparousparturients in more advanced stages of labor. 16 Thestudy was inadequately powered for a multivariatelogistic regression model because of the low numberof failure cases. Different infusion and PCEA groupsize limits meaningful comparisons. Future researchshould seek to delineate a causative relationship be-tween factors identified and failure. REFERENCES 1. Hawkins JL, Koonon LM, Palmer SK, Gibbs CP. Anesthesia-related deaths during obstetric delivery in the United States,1979–1990. Anesthesiology 1997;86:277–842. Report on confidential enquiries into maternal deaths in En-gland and Wales 1979–1981. Department of Health and SocialSecurity. Report on Health and Social Subjects 11,14,26,29.London: HMSO, 19863. Bromage PR. Epidural Analgesia. Philadelphia: WB Saunders,1978;1444. Riley ET, Papasin J. Epidural catheter function during laborpredicts anesthetic efficacy for subsequent Cesarean delivery.Int J Obstet Anesth 2002;11:81–45. Tortosa JC, Parry NS, Mercier FJ, Mazoit JX, Benhamou D.Efficacy of augmentation of epidural analgesia for caesareansection. Br J Anaesth 2003;91:532–56. Price ML, Reynolds F. Extending epidural blockade for emer-gency Caesarean section. Int J Obstet Anesth 1991;1:13–187. Dickson MAS, Jenkins J. Extension of epidural blockade foremergency caesarean section. Anaesthesia 1994;94:636–88. Lucas DN, Yentis SM, Kinsella SM. Urgency of Caesareansection: a new classification. J R Soc Med 2000;93:346–509. Morgan BM, Magni V. Anaesthesia for emergency caesareansection. Br J Obstet Gynaecol 1990;97:420–410. Orbach-Zinger S, Friedman L, Avramovich A, Ilgiaeva N,Orvieto R, Sulkes J, Eidelman LA. Risk factors for failure toextend labor epidural analgesia to epidural anesthesia forcesarean section. Acta Anaesthesiol Scand 2006;50:793–711. Garry M, Davies S. Failure of regional blockade for caesareansection. Int J Obstet Anesth 2002;11:9–1212. Eappen S, Blinn A, Segal S. Incidence of epidural catheterreplacement in parturients: a retrospective chart review. Int JObstet Anesth 1998;7:220–2513. Norris MC. Are combined spinal-epidural catheters reliable? Int J Obstet Anesth 2000;9:3–614. Pan PH, Bogard TD, Owen MD. Incidence and characteristics of failures in obstetric neuraxial analgesia and anesthesia: a retro-spective analysis of 19,259 deliveries. Int J Obstet Anesth2004;13:227–3315. SiaAT,CamannWR,OcampoCE,GoyRW,TanHM,RajammalS.Neuraxial block for labor analgesia- Is the combined spinal epi-dural (CSE) modality a good alternative to conventional epiduralanalgesia? Singapore Med J 2003;44:464–7016. Kan RK, Lew E, Yeo SW, Thomas E. General anesthesia forcesarean section in a Singapore maternity hospital: a retrospec-tive survey. Int J Obstet Anesth 2004;13:221–6 254  Brief Report  ANESTHESIA  &  ANALGESIA
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