PDPH is a common complication of neuraxial blockade in parturients: a meta-analysis of obstetrical studies

Combined spinal-epidural versus epidural analgesia for labor and delivery

The rapid onset of analgesia and improved mobility with combined spinal-epidural (CSE) techniques has been associated with a higher degree of maternal satisfaction compared with conventional epidural analgesia. However, controversy exists in that initiation of labor analgesia with a CSE may be associated with an increased risk for nonreassuring fetal status (ie, fetal bradycardia) and a subsequent need for emergent cesarean delivery. Overall, both epidural and CSE techniques possess unique risk/benefit profiles, and the decision to use one technique rather than the other should be determined based on individual patient and clinical circumstances.

Epidural catheter placement in morbidly obese parturients with the use of an epidural depth equation prior to ultrasound visualization

Background. Previously, Balki determined the Pearson correlation coefficient with the use of ultrasound (US) was 0.85 in morbidly obese parturients. We aimed to determine if the use of the epidural depth equation (EDE) in conjunction with US can provide better clinical correlation in estimating the distance from the skin to the epidural space in morbidly obese parturients. Methods. One hundred sixty morbidly obese (≥40 kg/m²) parturients requesting labor epidural analgesia were enrolled. Before epidural catheter placement, EDE was used to estimate depth to the epidural space. This estimation was used to help visualize the epidural space with the transverse and midline longitudinal US views and to measure depth to epidural space. The measured epidural depth was made available to the resident trainee before needle insertion. Actual needle depth (ND) to the epidural space was recorded. Results. Pearson's correlation coefficients comparing actual (ND) versus US estimated depth to the epidural space in the longitudinal median and transverse planes were 0.905 (95% CI: 0.873 to 0.929) and 0.899 (95% CI: 0.865 to 0.925), respectively. Conclusion. Use of the epidural depth equation (EDE) in conjunction with the longitudinal and transverse US views results in better clinical correlation than with the use of US alone.

Posture and fluids for preventing post-dural puncture headache

BACKGROUND

Post-dural puncture headache (PDPH) is a common complication of lumbar punctures. Several theories have identified the leakage of cerebrospinal fluid (CSF) through the hole in the dura as a cause of this side effect. Therefore, it is necessary to take preventive measures to avoid this complication. Prolonged bed rest has been used as a therapeutic measure once PDPH has started, but it is unknown if it can be also be used to prevent it. Similarly, the value of administering fluids additional to those of normal dietary intake to restore the loss of CSF produced by the puncture is unknown.

OBJECTIVES

To assess whether prolonged bed rest combined with different body and head positions, as well as administration of supplementary fluids after lumbar puncture, prevent the onset of PDPH in people undergoing lumbar puncture for diagnostic or therapeutic purposes.

SEARCH METHODS

We searched the Cochrane Controlled Trials Register, MEDLINE, EMBASE, and LILACS up to June 2013.

SELECTION CRITERIA

We identified randomized controlled trials (RCTs) that compared the effects of bed rest versus early/immediate mobilization, head-down tilt versus horizontal position, prone versus supine positions during bed rest, and administration of supplementary fluids versus no/less supplementation, as prevention measures for PDPH in people who have undergone lumbar puncture.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the studies for eligibility through the web-based software EROS (Early Review Organizing Software). Two different review authors independently assessed risk of bias using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions. We solved any disagreements by consensus. We extracted data on cases of PDPH, severe PDPH, and any headache after lumbar puncture and performed intention-to-treat analyses and sensitivity analyses by risk of bias.

MAIN RESULTS

We included 23 trials (2477 participants) in this review. There was no beneficial effect associated with bed rest compared with immediate mobilization on the incidence of PDPH (risk for bed rest 26.4%; risk for mobilization 20.5%; risk ratio (RR) 1.30; 95% confidence interval (CI) 1.09 to 1.55), severe PDPH (risk for bed rest 10.6%; risk for mobilization 10.7%; RR 1.00; 95% CI 0.75 to 1.32), and presence of any headache after lumbar puncture (risk for bed rest 33.6%; risk for mobilization 28.6%; RR 1.18; 95% CI 1.05 to 1.32). Analyses restricted to the most methodologically rigorous trials gave similar results. Likewise, the two trials that assessed fluid supplementation did not find this preventive measure to be useful in the prevention of PDPH.

AUTHORS' CONCLUSIONS

There is no evidence from RCTs that suggests that routine bed rest after dural puncture is beneficial for the prevention of PDPH onset. The role of fluid supplementation in the prevention of PDPH remains unclear.

[Post-dural puncture headache and blood-patch: theoretical and practical approach]

OBJECTIVE

To review the current research and formulate a rational approach to the physiopathology, cause and treatment of post-dural puncture headache (PDPH).

DATA SOURCES

Articles published to December 2011 were obtained through a search of Medline for the MeSh terms "epidural blood-patch" and "post-dural puncture headache".

STUDY SELECTION

Six hundred and eighty-two pertinent studies were included and 200 were analysed.

DATA SYNTHESIS

Resulting of a dural tap after spinal anaesthesia or diagnostic lumbar puncture or as a complication of epidural anaesthesia, PDPH occurs when an excessive leak of cerebrospinal fluid leads to intracranial hypotension associated to a resultant cerebral vasodilatation. Reduction in cerebrospinal fluid volume in upright position may cause traction of the intracranial structure and stretching of vessels. Typically postural, headache may be associated to nausea, photophobia, tinnitus or arm pain and changes in hearing acuity. In severe cases, there may be cranial nerve dysfunction and nerve palsies secondary to traction on those nerves. The Epidural Blood-Patch (EBP) is considered as the "gold standard" in the treatment of PDHP because it induces a prolonged elevation of subarachnoid and epidural pressures, whereas such elevation is transient with saline or dextran. EBP should be performed within 24-48hours of onset of headache; the optimum volume of epidural blood appears to be 15-20mL. Severe complications following EBP are exceptional. The use of echography may be safety puncture. The optimum timing of epidural blood-patch, the resort of repeating procedure if the symptomatology does not disappear, the alternative to the conventional medical treatment need to be determined by future clinical trial.

Prevention of post-dural puncture headache in parturients: a systematic review and meta-analysis

Post-dural puncture headaches (PDPHs) present an important clinical problem. We assessed methods to decrease accidental dural punctures (ADPs) and interventions to reduce PDPH following ADP. Multiple electronic databases were searched for randomised clinical trials (RCTs) of parturients having labour epidurals, in which the studied intervention could plausibly affect ADP or PDPH, and the incidence of at least one of these was recorded. Forty RCTs (n = 11,536 epidural insertions) were included, studying combined spinal-epidurals (CSEs), loss of resistance medium, prophylactic epidural blood patches, needle bevel orientation, ultrasound-guided insertion, epidural morphine, Special Sprotte needles, acoustic-guided insertion, administration of cosyntropin, and continuous spinal analgesia. The RCTs for CSE, loss of resistance medium, and prophylactic epidural blood patches were meta-analysed. Five methods reduced PDPH: prophylactic epidural blood patch {four trials, median quality score = 2, risk difference = -0.48 [95% confidence interval (CI): -0.88 to -0.086]}, lateral positioning of the epidural needle bevel upon insertion (one trial, quality score = 1), Special Sprotte needles [one trial, quality score = 5, risk difference = -0.44 (95% CI: -0.67 to -0.21)], epidural morphine [one trial, quality score = 4, risk difference = -0.36 (95% CI -0.59 to -0.13)], and cosyntropin [one trial, quality score = 5, risk difference = -0.36 (95% CI -0.55 to -0.16)]. Several methods potentially reduce PDPH. Special Sprotte needles, epidural morphine, and cosyntropin are thus far each supported by a single, albeit good quality trial. Prophylactic blood patches are supported by three trials, but these had flawed methodology. Mostly, trials were of limited quality, and further well-conducted, large studies are needed.

Drug therapy for preventing post-dural puncture headache

BACKGROUND

Post-dural (post-lumbar or post-spinal) puncture headache (PDPH) is one of the most common complications of diagnostic, therapeutic or inadvertent lumbar punctures. Many drug options have been used to prevent headache in clinical practice and have also been tested in some clinical studies, but there are still some uncertainties about their clinical effectiveness.

OBJECTIVES

To assess the effectiveness and safety of drugs for preventing PDPH in adults and children.

SEARCH METHODS

The search strategy included the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2012, Issue 5), MEDLINE (from 1950 to May 2012), EMBASE (from 1980 to May 2012) and CINAHL (from 1982 to June 2012). There was no language restriction.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) that assessed the effectiveness of any drug used for preventing PDPH.

DATA COLLECTION AND ANALYSIS

Review authors independently selected studies, assessed risks of bias and extracted data. We estimated risk ratios (RR) for dichotomous data and mean differences (MD) for continuous outcomes. We calculated a 95% confidence interval (CI) for each RR and MD. We did not undertake meta-analysis because participants' characteristics or assessed doses of drugs were too different in the included studies. We performed an intention-to-treat (ITT) analysis.

MAIN RESULTS

We included 10 RCTs (1611 participants) in this review with a majority of women (72%), mostly parturients (women in labour) (913), after a lumbar puncture for regional anaesthesia. Drugs assessed were epidural and spinal morphine, spinal fentanyl, oral caffeine, rectal indomethacin, intravenous cosyntropin, intravenous aminophylline and intravenous dexamethasone.All the included RCTs reported data on the primary outcome, i.e. the number of participants affected by PDPH of any severity after a lumbar puncture. Epidural morphine and intravenous cosyntropin reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to placebo. Also, intravenous aminophylline reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to no intervention, while intravenous dexamethasone increased it. Spinal morphine increased the number of participants affected by pruritus when compared to placebo, and epidural morphine increased the number of participants affected by nausea and vomiting when compared to placebo. Oral caffeine increased the number of participants affected by insomnia when compared to placebo.The remainder of the interventions analysed did not show any relevant effect for any of the outcomes.None of the included RCTs reported the number of days that patients stayed in hospital.

AUTHORS' CONCLUSIONS

Morphine and cosyntropin have shown effectiveness for reducing the number of participants affected by PDPH of any severity after a lumbar puncture, when compared to placebo, especially in patients with high risk of PDPH, such as obstetric patients who have had an inadvertent dural puncture. Aminophylline also reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to no intervention in patients undergoing elective caesarean section. Dexamethasone increased the risk of PDPH, after spinal anaesthesia for caesarean section, when compared to placebo. Morphine also increased the number of participants affected by adverse events (pruritus and nausea and vomiting)There is a lack of conclusive evidence for the other drugs assessed (fentanyl, caffeine, indomethacin and dexamethasone).These conclusions should be interpreted with caution, owing to the lack of information, to allow correct appraisal of risk of bias and the small sample sizes of studies.

Insertion of an intrathecal catheter following accidental dural puncture: a meta-analysis

BACKGROUND

Inserting an intrathecal catheter after accidental dural puncture in parturients to prevent postdural puncture headache is becoming increasingly popular. We aimed to identify relevant published articles investigating this intervention and subject data to a meta-analysis.

METHODS

A systematic literature search was performed, paralleled by a hand search of abstract publications. Studies that reported the dichotomous outcome parameters postdural puncture headache or need for an epidural blood patch were considered eligible. Risk ratios with 95% confidence intervals were calculated.

RESULTS

We identified nine reports investigating placement of intrathecal catheters after accidental dural puncture. The risk ratio for an epidural blood patch after intrathecal catheter insertion was 0.64 (95% CI 0.49-0.84, P=0.001). The risk ratio for postdural puncture headache was 0.82 (95% CI 0.67-1.01, P=0.06).

DISCUSSION

Inserting an intrathecal catheter significantly reduced the risk for an epidural blood patch; the incidence of postdural puncture headache was reduced but not significantly. Accidental dural puncture is a rare complication and therefore trials on intervention need to include a large number of patients which is time-consuming and costly. Intrathecal catheterisation is a promising approach for the prevention of postdural puncture headache and should be evaluated further. This intervention has additional benefits including a reduced risk of repeat dural puncture, rapid onset of action and use for anaesthesia.

Analgesia in Obstetrics

Background: An effective relief of labour pain has become an important part of obstetric medicine. Therefore regional nerve blocks, systemic analgesic and non-pharmacologic techniques are commonly used. This review article gives a summary of pathophysiology and anatomy of labour pain as well as advantages, disadvantages, risks and adverse reactions of analgesic techniques in newborns and parturients. Methods: We performed a selective literature search in Medline via PubMed using the search-terms "Analgesia" and "Obstetrics". We also included the current guidelines of the German Society for Anesthesiology and Intensive Care Medicine. Results: PDA and CSE are safe techniques for the relief of labour pain if contraindications are excluded. The risk for instrumental delivery but not for caesarean section is increased under neuraxial analgesia. PDA and CSE should be performed in an early stage of labour using low doses of local anaesthetics if possible. It is not necessary to wait for a defined cervical dilatation before starting neuraxial analgesia. Anesthesiologists and obstetricians should inform patients as soon as possible before the situation of stress during labour. Systemic opioid analgesia is a possible alternative for neuraxial techniques. Because of possible side effects systemic remifentanil analgesia should only be performed under continuous monitoring. Several nonpharmacologic methods can also relieve labour pain, but results of studies about their effectiveness are inconsistent.

Post-dural (post-lumbar) puncture headache: risk factors and clinical features

OBJECTIVE

This is an analytic, interventional, cross sectional study to evaluate the risk factors of post-dural (post-lumbar) puncture headache (PDPH) and the validity of the diagnostic criteria for PDPH from the ICHD II.

METHODS

Six-hundred-and-forty patients (332 non-pregnant women and 308 men) aged 8-65 years underwent spinal anesthesia with Quincke 25G or 27G needles in elective surgery.

RESULTS

Forty-eight (7.5%) of the patients developed PDPH. The binary logistic regression analysis identified as risk factors: gender [11.1% female vs. 3.6% male, OR 2.25 (1.07-4.73); p = 0.03], age [11.0% 31-50 years of age vs. 4.2% others, OR 2.21 (1.12-4.36); p = 0.02], previous history of PDPH [26.4% positive vs. 6.2% negative, OR 4.30 (1.99-9.31); p < 0.01] and bevel orientation [16.1% perpendicular vs. 5.7% parallel, OR 2.16 (1.07-4.35); p = 0.03]. The period of latency between lumbar puncture and headache onset range from 6 to 72 hours and the duration from 3 to 15 days. In 34/48 (71%) patients with PDPH, at least one of the following was present: neck stiffness, tinnitus, hypoacusia, photophobia, or nausea.

CONCLUSION

In conclusion, 14/48 patients (29%) suffered none of the above-mentioned symptoms, indicating that a significant number of patients may suffer from PDPH in the absence of any symptoms apart from the headache itself. This suggests that a further analyses of existing studies should be made to determine if a criteria change may need consideration.

Systematic review of methods used in meta-analyses where a primary outcome is an adverse or unintended event

BACKGROUND

Adverse consequences of medical interventions are a source of concern, but clinical trials may lack power to detect elevated rates of such events, while observational studies have inherent limitations. Meta-analysis allows the combination of individual studies, which can increase power and provide stronger evidence relating to adverse events. However, meta-analysis of adverse events has associated methodological challenges. The aim of this study was to systematically identify and review the methodology used in meta-analyses where a primary outcome is an adverse or unintended event, following a therapeutic intervention.

METHODS

Using a collection of reviews identified previously, 166 references including a meta-analysis were selected for review. At least one of the primary outcomes in each review was an adverse or unintended event. The nature of the intervention, source of funding, number of individual meta-analyses performed, number of primary studies included in the review, and use of meta-analytic methods were all recorded. Specific areas of interest relating to the methods used included the choice of outcome metric, methods of dealing with sparse events, heterogeneity, publication bias and use of individual patient data.

RESULTS

The 166 included reviews were published between 1994 and 2006. Interventions included drugs and surgery among other interventions. Many of the references being reviewed included multiple meta-analyses with 44.6% (74/166) including more than ten. Randomised trials only were included in 42.2% of meta-analyses (70/166), observational studies only in 33.7% (56/166) and a mix of observational studies and trials in 15.7% (26/166). Sparse data, in the form of zero events in one or both arms where the outcome was a count of events, was found in 64 reviews of two-arm studies, of which 41 (64.1%) had zero events in both arms.

CONCLUSIONS

Meta-analyses of adverse events data are common and useful in terms of increasing the power to detect an association with an intervention, especially when the events are infrequent. However, with regard to existing meta-analyses, a wide variety of different methods have been employed, often with no evident rationale for using a particular approach. More specifically, the approach to dealing with zero events varies, and guidelines on this issue would be desirable.

Pain management for women in labour: an overview of systematic reviews

BACKGROUND

The pain that women experience during labour is affected by multiple physiological and psychosocial factors and its intensity can vary greatly.  Most women in labour require pain relief. Pain management strategies include non-pharmacological interventions (that aim to help women cope with pain in labour) and pharmacological interventions (that aim to relieve the pain of labour).

OBJECTIVES

To summarise the evidence from Cochrane systematic reviews on the efficacy and safety of non-pharmacological and pharmacological interventions to manage pain in labour. We considered findings from non-Cochrane systematic reviews if there was no relevant Cochrane review.

METHODS

We searched the Cochrane Database of Systematic Reviews (The Cochrane Library 2011, Issue 5), The Cochrane Database of Abstracts of Reviews of Effects (The Cochrane Library 2011, Issue 2 of 4), MEDLINE (1966 to 31 May 2011) and EMBASE (1974 to 31 May 2011) to identify all relevant systematic reviews of randomised controlled trials of pain management in labour. Each of the contributing Cochrane reviews (nine new, six updated) followed a generic protocol with 13 common primary efficacy and safety outcomes. Each Cochrane review included comparisons with placebo, standard care or with a different intervention according to a predefined hierarchy of interventions. Two review authors extracted data and assessed methodological quality, and data were checked by a third author. This overview is a narrative summary of the results obtained from individual reviews.

MAIN RESULTS

We identified 15 Cochrane reviews (255 included trials) and three non-Cochrane reviews (55 included trials) for inclusion within this overview. For all interventions, with available data, results are presented as comparisons of: 1. Intervention versus placebo or standard care; 2. Different forms of the same intervention (e.g. one opioid versus another opioid); 3. One type of intervention versus a different type of intervention (e.g. TENS versus opioid). Not all reviews included results for all comparisons. Most reviews compared the intervention with placebo or standard care, but with the exception of opioids and epidural analgesia, there were few direct comparisons between different forms of the same intervention, and even fewer comparisons between different interventions. Based on these three comparisons, we have categorised interventions into: " What works" ,"What may work", and "Insufficient evidence to make a judgement".WHAT WORKSEvidence suggests that epidural, combined spinal epidural (CSE) and inhaled analgesia effectively manage pain in labour, but may give rise to adverse effects. Epidural, and inhaled analgesia effectively relieve pain when compared with placebo or a different type of intervention (epidural versus opioids). Combined-spinal epidurals relieve pain more quickly than traditional or low dose epidurals. Women receiving inhaled analgesia were more likely to experience vomiting, nausea and dizziness.When compared with placebo or opioids, women receiving epidural analgesia had more instrumental vaginal births and caesarean sections for fetal distress, although there was no difference in the rates of caesarean section overall. Women receiving epidural analgesia were more likely to experience hypotension, motor blockade, fever or urinary retention. Less urinary retention was observed in women receiving CSE than in women receiving traditional epidurals. More women receiving CSE than low-dose epidural experienced pruritus.  WHAT MAY WORKThere is some evidence to suggest that immersion in water, relaxation, acupuncture, massage and local anaesthetic nerve blocks or non-opioid drugs may improve management of labour pain, with few adverse effects.  Evidence was mainly limited to single trials. These interventions relieved pain and improved satisfaction with pain relief (immersion, relaxation, acupuncture, local anaesthetic nerve blocks, non-opioids) and childbirth experience (immersion, relaxation, non-opioids) when compared with placebo or standard care. Relaxation was associated with fewer assisted vaginal births and acupuncture was associated with fewer assisted vaginal births and caesarean sections.INSUFFICIENT EVIDENCEThere is insufficient evidence to make judgements on whether or not hypnosis, biofeedback, sterile water injection, aromatherapy, TENS, or parenteral opioids are more effective than placebo or other interventions for pain management in labour. In comparison with other opioids more women receiving pethidine experienced adverse effects including drowsiness and nausea. 

AUTHORS' CONCLUSIONS

Most methods of non-pharmacological pain management are non-invasive and appear to be safe for mother and baby, however, their efficacy is unclear, due to limited high quality evidence. In many reviews, only one or two trials provided outcome data for analysis and the overall methodological quality of the trials was low. High quality trials are needed.There is more evidence to support the efficacy of pharmacological methods, but these have more adverse effects. Thus, epidural analgesia provides effective pain relief but at the cost of increased instrumental vaginal birth.It remains important to tailor methods used to each woman's wishes, needs and circumstances, such as anticipated duration of labour, the infant's condition, and any augmentation or induction of labour.A major challenge in compiling this overview, and the individual systematic reviews on which it is based, has been the variation in use of different process and outcome measures in different trials, particularly assessment of pain and its relief, and effects on the neonate after birth. This made it difficult to pool results from otherwise similar studies, and to derive conclusions from the totality of evidence. Other important outcomes have simply not been assessed in trials; thus, despite concerns for 30 years or more about the effects of maternal opioid administration during labour on subsequent neonatal behaviour and its influence on breastfeeding, only two out of 57 trials of opioids reported breastfeeding as an outcome. We therefore strongly recommend that the outcome measures, agreed through wide consultation for this project, are used in all future trials of methods of pain management.

Overview of anesthetic considerations for Cesarean delivery

INTRODUCTION

Physiologic changes of pregnancy uniquely influence anesthesia for Cesarean delivery. Included is a review of current obstetrical anesthesia considerations for Cesarean delivery and recent changes improving maternal care and outcome.

SOURCES OF DATA

A literature review was conducted using Pubmed and the Cochrane database.

AREAS OF AGREEMENT AND CONTROVERSY

Increased use of neuraxial techniques instead of general anesthesia for Cesarean delivery has improved maternal safety. Recent changes in the prevention of gastric aspiration, hypotension from neuraxial techniques, venous thrombosis and a team approach have improved maternal care. Elective Cesarean deliveries and management of urgent deliveries are areas of discussion.

AREAS TIMELY FOR DEVELOPING RESEARCH

Obstetric anesthesia advances have improved maternal outcomes. Current areas of needed obstetric anesthesia research include improved obese patient care, the impact of anticoagulation on neuraxial techniques in pregnancy, long-term neurocognitive effects of neonatal exposure to anesthesia and postoperative pain management.

A prospective controlled study of continuous spinal analgesia versus repeat epidural analgesia after accidental dural puncture in labour

BACKGROUND

After accidental dural puncture in labour it is suggested that inserting an intrathecal catheter and converting to spinal analgesia reduces postdural puncture headache and epidural blood patch rates. This treatment has never been tested in a controlled manner.

METHODS

Thirty-four hospitals were randomised to one of two protocols for managing accidental dural puncture during attempted labour epidural analgesia: repeating the epidural procedure or converting to spinal analgesia by inserting the epidural catheter intrathecally. Hospitals changed protocols at six-month intervals for two years.

RESULTS

One hundred and fifteen women were recruited but 18 were excluded from initial analysis because of practical complications which had the potential to affect the incidence of headache and blood patch rates. Of the remaining 97 women, 47 were assigned to the repeat epidural group and 50 to the spinal analgesia group. Conversion to spinal analgesia did not reduce the incidence of postdural puncture headache (spinal 72% vs. epidural 62%, P=0.2) or blood patch (spinal 50% vs. epidural 55%, P=0.6). Binary logistic analysis revealed the relative risk of headache increased with 16-gauge vs. 18-gauge epidural needles (RR=2.21, 95% CI 1.4-2.6, P=0.005); anaesthetist inexperience (RR=1.02 per year difference in experience, 95% CI 1.001-1.05, P=0.043), and spontaneous vaginal compared to caesarean delivery (RR=1.58, 95% CI 1.14-1.79, P=0.02). These same factors also increased the risk of a blood patch: 16-gauge vs. 18-gauge needles (RR=2.92, 95% CI 1.37-3.87, P=0.01), anaesthetist inexperience (RR=1.06 per year difference in experience, 95% CI 1.02-1.09, P=0.006), spontaneous vaginal versus caesarean delivery (RR=2.22, 95% CI 1.47-2.63, P=0.002). When all patients were included for analysis of complications, there was a significantly greater requirement for two or more additional attempts to establish neuraxial analgesia associated with repeating the epidural (41% vs. 12%, P=0.0004) and a 9% risk of second dural puncture.

CONCLUSIONS

Converting to spinal analgesia after accidental dural puncture did not reduce the incidence of headache or blood patch, but was associated with easier establishment of neuraxial analgesia for labour. The most significant factor increasing headache and blood patch rates was the use of a 16-gauge compared to an 18-gauge epidural needle.

Novel pulsatile cerebrospinal fluid model to assess pressure manometry and fluid sampling through spinal needles of different gauge: support for the use of a 22 G spinal needle with a tapered 27 G pencil-point tip

BACKGROUND

Parallel-walled spinal needles ≤ 22 G are routinely used for lumbar puncture, despite a reported ≥ 32% incidence of post-dural puncture headache. A tapered spinal needle (22 G shaft, 27 G tip) is in use in our institution. We hypothesized that despite the smaller dural puncture hole, this needle has similar cerebrospinal fluid (CSF) pressure equilibration times and CSF sampling times to a standard 22 G needle and assessed a range of spinal needles using an experimental pulsatile CSF reservoir.

METHODS

The pulsatile CSF reservoir had an oscillating pressure varying between 25 and 15 cm H(2)O at a cycle frequency of 80 s(-1). We tested seven parallel-walled spinal needles (18-27 G) and the tapered 22/27 G needle. CSF pressure was measured every 2 s by manometry. The time to collect 1 ml CSF samples was measured. Saline 0.9% and mannitol 20% were tested separately. One-way ANOVA with Bonferroni post-hoc test was used to compare 22G, 27G and 22/27G needles.

RESULTS

The mean [standard deviation (sd)] CSF pressure equilibration time (saline) was 40.7 (6.4), 108.7 (6.1), and 51.3 (4.6) s for the 22, 27, and 22/27 G needles (P< 0.0001 for comparisons between 27 G and other needles). The mean (sd) CSF sampling time (saline) was 40.3 (3.1), 225.3 (10.0), and 63.0 (5.2) s for the 22, 27, and 22/27 G needles (P< 0.0001 for comparisons between 27 G and other needles, and P= 0.019 between 22 and 22/27 G needles). Saline was different from mannitol for both measurements and all needles (P< 0.0001).

CONCLUSIONS

A 22/27 G tapered spinal needle has similar flow properties to the 22 G needle, despite a 27 G tip.

Cephalad angulation of epidural needle insertion may be an important factor for safe epidural space approach: a mathematical model

BACKGROUND AND OBJECTIVES

Epidural approach angle is one of the determining factors for needle traveling length to reach the epidural space. Likewise, the margin of safety against accidental dural puncture should be affected by epidural approach angle because the space available for epidural needle tip movement in the epidural space is depending on the inserting angle to the epidural space. The purpose of this study is to conjecture the effect of the angle formed with the skin and an epidural needle on the margin of safety against accidental dural puncture using a mathematical model.

CASE REPORT

Suppose that the width of the epidural space is A mm and that the force advancing the epidural catheter is Ckgf and the diameter of the catheter is D mm. In this situation, assuming that the cephalad angle with the midline approach formed with the skin and an epidural needle is θ, the following parameters can be determined: the available distance for the needle tip in the epidural space = A/sinθmm; cephalad advancing force of catheter = C*cosθkgf; and the pressure at the site of dura matter where the epidural catheter is pushing = 400*C*sinθ.πD(-2)kgf.cm(-2). The longer the distance available for the needle tip, the larger the margin of safety for dura injury by the epidural needle. It is supposed that θ should be set smaller to make the margin of safety larger. Likewise, smaller θ could decrease the pushing pressure and more effectively create a distinct cephalad advancing force.

CONCLUSIONS

Acute cephalad angulation should be considered to increase the margin of safety for epidural approach and catheterization.

Drug therapy for treating post-dural puncture headache

BACKGROUND

Post-dural puncture headache (PDPH) is the most common complication of lumbar puncture, an invasive procedure frequently performed in the emergency room. Numerous pharmaceutical drugs have been proposed to treat PDPH but there are still some uncertainties about their clinical effectiveness.

OBJECTIVES

To assess the effectiveness and safety of drugs for treating PDPH in adults and children.

SEARCH STRATEGY

The search strategy included the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2011, Issue 2), MEDLINE (from 1950 to June 2011), EMBASE (from 1980 to June 2011) and CINAHL (from 1982 to June 2011). There was no language restriction.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) assessing the effectiveness of any pharmacological drug used for treating PDPH.

DATA COLLECTION AND ANALYSIS

Review authors independently selected studies, assessed risks of bias and extracted data. We estimated risk ratios (RR) for dichotomous data and mean differences (MD) for continuous outcomes. We calculated a 95% confidence interval (CI) for each RR and MD. We did not undertake meta-analysis because the included studies assessed different sorts of drugs or different outcomes. We performed an intention-to-treat (ITT) analysis.

MAIN RESULTS

We included seven RCTs (200 participants) in this review (between 88% and 90.5% were women; mostly parturients (84% to 87%) after a lumbar puncture for a regional anaesthesia). Pharmacological drugs assessed were oral and intravenous caffeine, subcutaneous sumatriptan, oral gabapentin, oral theophylline, intravenous hydrocortisone and intramuscular adrenocorticotropic hormone (ACTH).One RCT reported data about PDPH persistence of any severity at follow up (primary outcome); caffeine reduced the number of participants with PDPH at one to two hours when compared to placebo. Treatment with caffeine also decreased the need for a conservative supplementary therapeutic option. Treatment with gabapentin versus placebo reported better visual analogue scale (VAS) scores after one, two, three and four days; treatment with hydrocortisone plus conventional treatment showed better VAS scores than conventional treatment alone at six, 24 and 48 hours and treatment with theophylline showed a lower mean "sum of pain" when compared with placebo. Sumatriptan and ACTH did not show any relevant effect for this outcome.There were no clinically significant drug adverse events.The rest of the outcomes were not reported by the RCTs or did not show any relevant effect.

AUTHORS' CONCLUSIONS

Caffeine has shown effectiveness for treating PDPH, decreasing the proportion of participants with PDPH persistence and those requiring supplementary interventions, when compared with placebo. Gabapentin, theophylline and hydrocortisone have also shown a decrease in pain severity scores when compared with placebo or conventional care.There is a lack of conclusive evidence for the other drugs assessed (sumatriptan and ACTH).These conclusions should be interpreted with caution, due to the lack of information to allow correct appraisal of risk of bias, the small sample sizes of studies and also the limited generalisability, as most participants were post-partum women in their 30s.

Complications of regional and general anaesthesia in obstetric practice

Any anaesthetic technique, either regional or general, has potential for complications. Moreover, it has been seen that in obstetric patients, the complications are potentiated due to pregnancy-related changes in physiology and due to various other factors. Increasing trend of caesarean section in the setting of increasing maternal age, obesity and other concomitant diseases will continue to challenge the obstetric anaesthetist in his/her task of providing safe regional and general anaesthesia. This review has highlighted the possible complications of regional and general anaesthesia encountered during the obstetric anaesthesia practice.

Intracranial subdural hematoma post-spinal anesthesia: report of two cases and review of 33 cases in the literature

BACKGROUND AND OBJECTIVES

Intracranial subdural hematoma is a rare complication of spinal anesthesia. We report two cases of women who developed chronic subdural hematoma post-spinal anesthesia diagnosed after prolonged clinical evolution of post-dural puncture headache (PDPH) and we analyze other 33 cases found on literature review.

CASE REPORTS

In 35 patients (ages 20-88 years, 19 males), 14 were older than 60 years (40%), of which 12 (86%) were males. The relationship is inverted in the group of younger patients (< 60 years), in which we observed twice as many women (14:7). Two peaks of higher incidence were observed: 30-39 years (31%) and 60-69 years (29%). The length of time from the beginning of symptoms until diagnosis ranged from 4 hours to 29 weeks. Headache was the main complaint in 26/35 (74.3%) patients; changes in the level of consciousness in 14/35 (40.0%); vomiting in 11/35 (31,4%); hemiplegia or hemiparesis in 8/35 (22.9%); diplopia or VI nerve paresis in 5/35 (14.3%); and language disorders in 4/35 (11.4%). Contributing factors included: pregnancy, multiple punctures, use of anticoagulants, intracranial vascular abnormalities, and brain atrophy. In 15 cases, a contributing factor was not mentioned. Four out of 35 patients (11.4%) remained with neurologic sequelae, and 4/35 (11.4%) died.

CONCLUSIONS

The presence of any of the signs or symptoms mentioned above should alert for the possibility of an intracranial subdural hematoma as a complication of puncture of the dura mater, especially in those patients with PDPH for more than one week, at which time investigation by neuroimaging is necessary.

Lower extremity radicular pain after prophylactic intrathecal saline injection through a subarachnoid catheter following accidental dural puncture

We describe a case in which severe lower extremity radicular pain occurred after administration of 0.9% saline into the subarachnoid space through a catheter that had been left for 20 h following inadvertent dural puncture in an obstetric patient. A 42-year-old (G8P7) woman was admitted for repeat cesarean delivery. Accidental dural puncture occurred during epidural placement. Following a slow 10-mL intrathecal injection of 0.9% normal saline an epidural catheter was advanced into the subarachnoid space. Spinal anesthesia was used for cesarean delivery and the subarachnoid catheter was kept in place for 20 h. Before catheter removal, an additional 10 mL of 0.9% saline was slowly administered into the intrathecal space. Almost instantly, the patient complained of back pain that progressed to lower extremity radicular pain and paresthesia; symptoms began to resolve after 10 min. Subsequently, the patient developed a postdural puncture headache that persisted for three days. The patient's radiculitis and paresthesia likely resulted from an acute increase in intrathecal pressure after saline administration or from direct catheter irritation. Although both intrathecal saline administration and subarachnoid catheter placement have been previously proposed as ways to prevent postdural puncture headache, their efficacy remains controversial, and we advise caution with these techniques.

Facial nerve paralysis and partial brachial plexopathy after epidural blood patch: a case report and review of the literature

We report a complication related to epidural analgesia for delivery in a 24- year-old woman who was admitted with mild pre-eclampsia and for induction of labor. At the first postpartum day she developed a postdural puncture headache, which was unresponsive to conservative measures. On the fifth day an epidural blood patch was done, and her headache subsided. Sixteen hours later she developed paralysis of the right facial nerve, which was treated with prednisone. Seven days later she complained of pain in the left arm and the posterior region of the shoulder. She was later admitted and diagnosed with partial brachial plexopathy.

Epidural analgesia for labor: Current techniques

Epidural analgesia is an extremely effective and popular treatment for labor pain. In this review, we trace the history of the use of epidural analgesia and its refinements. We then outline the goals of treatment and methods used to attain those goals. The use of low concentrations of local anesthetics, combined with lipid-soluble opioids, does not impede the progress of labor or depress the newborn. The incidence of side effects is low. Maintenance of analgesia that allows patient control enhances patient satisfaction.

Advances in labor analgesia

The pain of childbirth is arguably the most severe pain most women will endure in their lifetimes. The pain of the early first stage of labor arises from dilation of the lower uterine segment and cervix. Pain from the late first stage and second stage of labor arises from descent of the fetus in the birth canal, resulting in distension and tearing of tissues in the vagina and perineum. An array of regional nerve blocks, systemic analgesic, and nonpharmacologic techniques are currently used for labor analgesia. Nonpharmacologic methods are commonly used, but the effectiveness of these techniques generally lacks rigorous scientific study. Continuous labor support has been shown to decrease the use of pharmacologic analgesia and shorten labor. Intradermal water injections decrease back labor pain. Neuraxial labor analgesia (most commonly epidural or combined spinal-epidural) is the most effective method of pain relief during childbirth, and the only method that provides complete analgesia without maternal or fetal sedation. Current techniques commonly combine a low dose of local anesthetic (bupivacaine or ropivacaine) with a lipid soluble opioid (fentanyl or sufentanil). Neuraxial analgesia does not increase the rate of cesarean delivery compared to systemic opioid analgesia; however, dense neuraxial analgesia may increase the risk of instrumental vaginal delivery.

Prevention of postdural puncture headache after accidental dural puncture: a quantitative systematic review

No clear consensus exists on how to best prevent severe headache from occurring after accidental dural puncture. We conducted a quantitative systematic review to identify all available evidence for the prevention of postdural puncture headache (PDPH) and included 17 studies with 1264 patients investigating prophylactic epidural blood patch (PEBP), epidural morphine, intrathecal catheters, and epidural or intrathecal saline. The relative risk (RR) for headache after PEBP was 0.48 [95% confidence interval (CI): 0.23-0.99] in five non-randomized controlled trials (non-RCTs) and 0.32 (0.10-1.03) in four randomized controlled trials (RCTs). The RR for epidural morphine (based on a single RCT) was 0.25 (0.08-0.78). All other interventions were based on non-RCTs and failed statistical significance, including long-term intrathecal catheters with an RR of 0.21 (0.02-2.65). There are a number of promising options to prevent PDPH, yet heterogeneity between the studies and publication bias towards small non-RCTs with positive results limits the available evidence. Thus, a large multicentre RCT is needed to determine the best preventative practices.

Intrathecal catheterization after unintentional dural puncture during orthopedic surgery

PURPOSE

We investigated whether inserting an intrathecal catheter and leaving it in place for 24 h after an unintentional dural puncture in orthopedic patients reduced the incidence of post-dural puncture headache (PDPH).

METHODS

The study consisted of 427 patients in whom a total of 21 unintentional dural punctures had occurred during orthopedic surgery performed between 2002 and 2006. Seven patients (phase I; evaluated retrospectively) each underwent placement of an epidural catheter at another level after dural puncture during the period January 2002 to February 2004. Fourteen patients (phase II; evaluated prospectively) received an epidural catheter through the dural tear after an unintentional dural puncture during the period February 2004-March 2006

RESULTS

In phase I, 5 of the 7 patients experienced PDPH, and one required an epidural blood patch. In phase II, only one of the 14 patients complained of PDPH, which resolved after 48 h of medical therapy. No patient experienced paresthesia, neurologic or hemorrhagic complication, or infection.

CONCLUSION

Inserting an epidural catheter through the dural tear following an unintentional dural puncture and leaving it in place for 24 h significantly reduces the incidence of PDPH.

Meningeal (postdural) puncture headache, unintentional dural puncture, and the epidural blood patch: a national survey of United States practice

BACKGROUND

Meningeal (postdural) puncture headache (MPH) is a familiar iatrogenic complication. The optimal means of prevention, management, and treatment of this disorder are uncertain. The purpose of this study was to determine current practice among United States (USA) anesthesiologists regarding MPH as well as the related issues of unintentional dural puncture (UDP), the epidural blood patch (EBP), and proposed alternatives to the EBP.

METHODS

A survey form was sent as a single mailing to each practicing USA member of the American Society of Regional Anesthesia and Pain Medicine in June 2006.

RESULTS

Data were analyzed from 1024 returned survey forms (29.4% response rate). Major findings were as follows: Written institutional protocols for managing UDP and MPH are uncommon. The preferred method of immediately dealing with an UDP when providing analgesia for labor is to reattempt the epidural at another level (73.4%). When intrathecal catheters are used for labor analgesia, they are most often removed immediately after delivery (56.5%). After UDP in the obstetric setting, aggressive hydration and encouraging bed rest are the most frequently used prophylactic measures against the development of MPH. Frequently used treatment options for MPH include aggressive hydration, the EBP, oral caffeine, oral nonopioid analgesics, and bed rest. With the exception of a uniform blood volume (16-20 mL), procedural details of the EBP vary considerably among practitioners. The use of materials other than blood for epidural patch is uncommon.

CONCLUSIONS

Various measures, many poorly supported by the literature, are used prophylactically after UDP and in the treatment of MPH. Despite being nearly universally used as treatment of MPH, the EBP procedure itself remains largely nonstandardized.

Observational study of continuous spinal anesthesia with the catheter-over-needle technique for cesarean delivery

BACKGROUND

Few studies have assessed the efficacy and safety of continuous spinal anesthesia in obstetrics, although placement of a catheter in the intrathecal space theoretically offers advantages in these patients.

METHODS

Ninety-two women scheduled for elective cesarean delivery using continuous spinal anesthesia with the catheter-over-needle technique (22- or 24-gauge Spinocath) were included in the study. The doses of local anesthetic used, hemodynamic variables, use of ephedrine and other drugs, and incidence of complications such as technical failure and postdural puncture headache (PDPH) were recorded.

RESULTS

The mean (+/-SD) dose of hyperbaric bupivacaine used was 8.2+/-1.8 mg. The incidence of hypotension was 30% and the mean total dose of ephedrine was 4+/-7 mg. The continuous spinal anesthetic technique failed in 18 women (20%). The overall incidence of post-dural-puncture headache was 29%; 18% of patients with post-dural-puncture headache required a blood patch.

CONCLUSIONS

Compared to previous reports, the incidence of block failure and PDPH in this study was unacceptably high and therefore the risks of the technique appear to outweigh the advantages of continuous spinal anesthesia in obstetric practice.

Immediate management of inadvertent dural puncture during insertion of a labour epidural: a survey of Australian obstetric anaesthetists

Immediate management of inadvertent dural puncture during insertion of an epidural needle during labour is controversial and evidence to guide clinical practice is limited. We surveyed Australian obstetric anaesthetists by anonymous postal questionnaire. Of the 671 surveys sent, 417 (62%) were returned. Following dural puncture, 265 respondents (64%) indicated that they "would usually remove the Tuohy needle and resite". The most common reason for this decision was concern regarding the safety of intrathecal catheters (ITC) (n = 236, 89%), in particular, the risk of misuse (n = 182, 70%). The most frequently reported reason for "usually inserting an ITC" was that this reduced the incidence (n = 120, 84%) and severity (n = 110, 77%) of post dural puncture headache. Increased frequency of ITC insertion was reported by respondents who practised more frequent sessions of obstetric anaesthesia, had fewer years of experience as a consultant anaesthetist and worked in a public hospital. The more widespread use of ITCs seems to be limited by safety concerns.

Accidental dural puncture and post dural puncture headache in obstetric anaesthesia: presentation and management: a 23-year survey in a district general hospital

Post dural puncture headache can be a debilitating complication of epidural and subarachnoid anaesthesia for a new mother. In a survey of 18,337 epidurals and 5021 subarachnoid blocks performed for obstetric procedures over a 23-year period in a district general hospital maternity unit, there were 167 recognised accidental dural punctures after epidurals (0.91%), with 147 patients (88%) developing post dural puncture headache. In addition there were 52 post dural puncture headaches after subarachnoid blocks (1.04%). Successful management of accidental dural puncture and post dural puncture headache requires adherence to clear policies and protocols, with close follow-up of patients by an experienced obstetric anaesthetist.