[Epidural anesthesia : Clinical application and current developments]

Epidural anesthesia has been an established procedure in anesthesia for many years. Possibly due to its invasiveness, the associated fear of serious complications and the proliferation of alternative methods, an overall decline in its use can be observed. Several alternative procedures have been developed, especially the introduction of ultrasound into anesthesia, which are increasingly being used in clinical practice. The aim of this continuing medical education (CME) article is to shed light on the remaining range of indications for epidural anesthesia, to present the approaches and possible clinical benefits as well as to evaluate the effects that go beyond pure analgesia, according to the current evidence. In addition, potential complications and preventive approaches are discussed. This article is based on a literature search in PubMed and Google Scholar.

High-fidelity is not superior to low-fidelity simulation but leads to overconfidence in medical students

BACKGROUND

Simulation has become integral to the training of both undergraduate medical students and medical professionals. Due to the increasing degree of realism and range of features, the latest mannequins are referred to as high-fidelity simulators. Whether increased realism leads to a general improvement in trainees' outcomes is currently controversial and there are few data on the effects of these simulators on participants' personal confidence and self-assessment.

METHODS

One-hundred-and-thirty-five fourth-year medical students were randomly allocated to participate in either a high- or a low-fidelity simulated Advanced Life Support training session. Theoretical knowledge and self-assessment pre- and post-tests were completed. Students' performance in simulated scenarios was recorded and rated by experts.

RESULTS

Participants in both groups showed a significant improvement in theoretical knowledge in the post-test as compared to the pre-test, without significant intergroup differences. Performance, as assessed by video analysis, was comparable between groups, but, unexpectedly, the low-fidelity group had significantly better results in several sub-items. Irrespective of the findings, participants of the high-fidelity group considered themselves to be advantaged, solely based on their group allocation, compared with those in the low-fidelity group, at both pre- and post-self-assessments. Self-rated confidence regarding their individual performance was also significantly overrated.

CONCLUSION

The use of high-fidelity simulation led to equal or even worse performance and growth in knowledge as compared to low-fidelity simulation, while also inducing undesirable effects such as overconfidence. Hence, in this study, it was not beneficial compared to low-fidelity, but rather proved to be an adverse learning tool.

Availability of cookies during an academic course session affects evaluation of teaching

OBJECTIVES

Results from end-of-course student evaluations of teaching (SETs) are taken seriously by faculties and form part of a decision base for the recruitment of academic staff, the distribution of funds and changes to curricula. However, there is some doubt as to whether these evaluation instruments accurately measure the quality of course content, teaching and knowledge transfer. We investigated whether the provision of chocolate cookies as a content-unrelated intervention influences SET results.

METHODS

We performed a randomised controlled trial in the setting of a curricular emergency medicine course. Participants were 118 third-year medical students. Participants were randomly allocated into 20 groups, 10 of which had free access to 500 g of chocolate cookies during an emergency medicine course session (cookie group) and 10 of which did not (control group). All groups were taught by the same teachers. Educational content and course material were the same for both groups. After the course, all students were asked to complete a 38-question evaluation form.

RESULTS

A total of 112 students completed the evaluation form. The cookie group evaluated teachers significantly better than the control group (113.4 ± 4.9 versus 109.2 ± 7.3; p = 0.001, effect size 0.68). Course material was considered better (10.1 ± 2.3 versus 8.4 ± 2.8; p = 0.001, effect size 0.66) and summation scores evaluating the course overall were significantly higher (224.5 ± 12.5 versus 217.2 ± 16.1; p = 0.008, effect size 0.51) in the cookie group.

CONCLUSIONS

The provision of chocolate cookies had a significant effect on course evaluation. These findings question the validity of SETs and their use in making widespread decisions within a faculty.

Intra- versus postoperative initiation of pain control via a thoracic epidural catheter for lumbar spinal fusion surgery

BACKGROUND

Thoracic epidural anesthesia (TEA) is one of the pillars of perioperative pain care. Particularly for spine surgery which causes significant postoperative pain TEA seems like an appealing option. However, beneficial effects of a TEA are questionable when the catheter is not used intraoperatively, a decision that is usually based on the surgeon's wish to perform immediate neurological examination postoperatively.

METHODS

Forty patients undergoing transforaminal lumbar interbody fusion surgery (TLIF) were randomized into two groups. Patients received preoperative insertion of a TEA. For patients in the intraoperative group an epidural infusion was started preoperatively and maintained throughout. For patients in the postoperative group the epidural infusion was started once neurological examination had been performed. The primary outcome measure in this study was postoperative requirements of piritramide during the first two postoperative hours. Secondary outcomes involved postoperative pain numeric rating scale (NRS) scores, intraoperative opioid requirements, side effects and ability to perform direct postoperative neurological examination.

RESULTS

Postoperative group patients required significantly more opioids both intra- and postoperatively (P=0.036 and P=0.039) and NRS scores were significantly higher on admission to recovery, at 30 and 60 min as compared to patients in the intraoperative group (P=0.013; P=0.004 and P=0.012). Early postoperative neurological examination was feasible in all patients in both groups.

CONCLUSIONS

Epidural catheters used intraoperatively during TLIF are feasible, significantly reduce pain, intra- and postoperative use of opioids and do not influence the quality of neurological tests directly after the surgical procedure.

How do authors of systematic reviews deal with research malpractice and misconduct in original studies? A cross-sectional analysis of systematic reviews and survey of their authors

OBJECTIVES

To study whether systematic reviewers apply procedures to counter-balance some common forms of research malpractice such as not publishing completed research, duplicate publications, or selective reporting of outcomes, and to see whether they identify and report misconduct.

DESIGN

Cross-sectional analysis of systematic reviews and survey of their authors.

PARTICIPANTS

118 systematic reviews published in four journals (Ann Int Med, BMJ, JAMA, Lancet), and the Cochrane Library, in 2013.

MAIN OUTCOMES AND MEASURES

Number (%) of reviews that applied procedures to reduce the impact of: (1) publication bias (through searching of unpublished trials), (2) selective outcome reporting (by contacting the authors of the original studies), (3) duplicate publications, (4) sponsors' and (5) authors' conflicts of interest, on the conclusions of the review, and (6) looked for ethical approval of the studies. Number (%) of reviewers who suspected misconduct are reported. The procedures applied were compared across journals.

RESULTS

80 (68%) reviewers confirmed their data. 59 (50%) reviews applied three or more procedures; 11 (9%) applied none. Unpublished trials were searched in 79 (66%) reviews. Authors of original studies were contacted in 73 (62%). Duplicate publications were searched in 81 (69%). 27 reviews (23%) reported sponsors of the included studies; 6 (5%) analysed their impact on the conclusions of the review. Five reviews (4%) looked at conflicts of interest of study authors; none of them analysed their impact. Three reviews (2.5%) looked at ethical approval of the studies. Seven reviews (6%) suspected misconduct; only 2 (2%) reported it explicitly. Procedures applied differed across the journals.

CONCLUSIONS

Only half of the systematic reviews applied three or more of the six procedures examined. Sponsors, conflicts of interest of authors and ethical approval remain overlooked. Research misconduct is sometimes identified, but rarely reported. Guidance on when, and how, to report suspected misconduct is needed.

Ability of a meta-analysis to prevent redundant research: systematic review of studies on pain from propofol injection

OBJECTIVE

To examine whether, according to the conclusions of a 2000 systematic review with meta-analysis on interventions to prevent pain from propofol injection that provided a research agenda to guide further research on the topic, subsequently published trials were more often optimally blinded, reported on children, and used the most efficacious intervention as comparator; and to check whether the number of new trials published each year had decreased and whether the designs of trials that cited the review differed from those that did not.

STUDY DESIGN

Systematic review comparing old trials (published before, and included in, the review) with new trials (published afterwards).

DATA SOURCES

Medline, Cochrane, Embase, and bibliographies to January 2013.

ELIGIBILITY CRITERIA FOR STUDY SELECTION

Randomised studies testing any intervention to prevent pain from propofol injection in humans.

RESULTS

136 new trials (19,778 patients) were retrieved. Compared with the 56 old trials (6264 patients), the proportion of optimally blinded trials had increased from 10.7% to 38.2% (difference 27.5%, 95% confidence interval 16.0% to 39.0%, P<0.001), and the proportion of trials that used the most efficacious intervention as comparator had increased from 12.5% to 27.9% (difference 15.4%, 4.0% to 26.9%, P=0.022). The proportion of paediatric trials had increased from 5.4% to 12.5%, although this was not significant (difference 7.1%, -1.0% to 15.2%, P=0.141). The number of new trials published each year was significantly higher (median number/year 12 (range 7-20) v 2.5 (0-9), P<0.001) with no obvious decreasing trend. 72.8% (n=99) of the new trials cited the review, with their designs similar to trials not citing the review. Only 36.0% (n=49) of the new trials were considered clinically relevant since they used the most efficacious intervention as comparator or included a paediatric population.

CONCLUSIONS

The impact of the systematic review on the design of subsequent research was low. There was an improvement in the reporting of optimal blinding procedures and a tendency towards an increase in the proportion of paediatric trials. The most efficacious intervention was more often chosen as comparator but remained marginally used, and the number of trials published per year had not decreased. The use of systematic reviews should be encouraged to inform rational, and thus ethical, trial design and improve the relevance of new research.

Procedural complications of central venous catheter insertion

BACKGROUND

Central venous catheters (CVC) have complication rates as high as 20% and are associated with significant morbidity and mortality. In this study we wished to determine the incidence of procedural related complications at different venous access sites as well as the impact of ultrasound (US) use, operator experience and level of supervision of trainees in a prospective observational study.

METHODS

Five hundred consecutive patients undergoing elective CVC insertion were prospectively followed. Data with regards to US use, operator experience, level of supervision, site of insertion and procedural complications were collected.

RESULTS

The overall rate of procedural complications was 19.5%. Operators with <25 insertions caused significantly more complications (25.2% vs. 13.6%). Arterial punctures occurred significantly more frequently when US was not used (7.2 vs. 2.1%) and at the subclavian site (8% vs. 1.6%). Higher levels of supervision were significantly associated with a decreased number of complications (10.7% vs. 23.8%). Subclavian vein as access point for the CVC resulted in significantly more overall complications (29.2% vs. 17.7%). Inexperienced operators combined with SCV approach were significant predictors for increased procedural-related complications.

CONCLUSION

Immediate procedural-related complications during CVC insertion are common. To reduce the incidence of procedural-related complications we advocate multiple strategies to assure central venous cannulation safety: 1) the internal jugular vein should be the primary target vessel; 2) trainees with <25 previous catheter insertions should be supervised at all times; 3) ultrasound may reduce the incidence of procedural-related complications.

[Neurologic complications after epidural analgesia]

Epidural analgesia is regarded as gold standard after major abdominal or thoracic surgery in combination with general anaesthesia. Apart from well documented positive effects of epidural analgesia on the postoperative period, evidence for the incidence of neurologic complications is less clear. Complications include direct spinal cord damage during epidural puncture, epidural hematoma, abscesses or meningitis. The review article gives an overview about current data on neurologic complications related to epidural analgesia and shows feasibility of prevention and early detection. Furthermore a therapeutic approach in case of a neurologic incident will be demonstrated.

Intraoperative thrombolysis in a patient with cardiopulmonary arrest undergoing caesarean delivery

Thromboembolic events during pregnancy remain a major cause of morbidity and mortality with possible catastrophic sequelae for the patient. The decision whether to use high-risk therapeutic thrombolytics during pregnancy or perinatally is complicated and many considerations pertain. We report on the thrombolytic management of a 34-year-old woman who had an asystolic cardiac arrest secondary to massive pulmonary embolism while undergoing emergency caesarean delivery. The patient was thrombolysed during successful cardiopulmonary resuscitation. Return of spontaneous circulation was accompanied by massive uterine bleeding. Instead of performing a postpartum hysterectomy, the uterus was preserved through continuous manual pressure and packing for four hours by the obstetric team until haemostasis was achieved. The patient survived and was later discharged without any major neurological deficit.

Continuous spinal anesthesia versus continuous femoral nerve block for elective total knee replacement

BACKGROUND

Continuous spinal analgesia (CSA) and continuous femoral nerve blockade (CFNB) are well-established procedures for postoperative pain relief. This study compares the efficacy, adverse effects and complications associated with these two analgesic methods in patients undergoing total knee arthroplasty (TKA).

METHODS

Data were analyzed from consecutive patients undergoing TKA under either CSA or spinal anesthesia plus CFNB. Quality of analgesia was assessed based on opioid consumption and pain intensity (visual analogue scale [VAS] where 0=no pain and 10=utmost imaginable pain) until postoperative day 4. In addition, joint mobility was assessed, and any adverse reactions or side effects were noted.

RESULTS

Sixty-two patients had satisfactory postoperative pain relief, and maximum pain scores were reported between 12 and 24 hrs. Median pain scores in the CSA group were significantly lower than those in the CFNB group (1.0 [0.9-1.9] vs. 2.0 [1.5-3.6] for resting pain and 2.0 [1.7-3.1] vs. 5.0 [3.0-5.5] for dynamic pain, respectively; P<0.001 for days 0 and 1; P<0.05 for all other days). Piritramide consumption was significantly higher in the CFNB group (P<0.01). There were no significant differences between the groups for postoperative mobility of the joint or patient satisfaction.

CONCLUSION

Both methods demonstrated analgesic efficacy after total knee arthroplasty, although there was less pain severity and opioid consumption use reported with continuous spinal analgesia. However, the use of continuous spinal analgesia is limited by concerns about the risk profile and absence of approved devices for continuous intrathecal infusion.

[Patient care according to the latest state of the science--implications of evidence-based medicine]

Evidence-based medicine implies that recommendations ideally exist for each clinical question based on a systematic data search in the current literature, a data extraction, a summary and critical appraisal. Over the last fifty years evidence-based medicine has been growing rapidly. Systematic reviews and randomised controlled trials are of high impact in this field. However, the question remains: in which way is daily clinical practice affected? In an era of time- and cost-pressures as well as manpower shortages, the complex process of evidence-based medicine is difficult. Examples from perioperative pain therapy are provided to demonstrate how evidence-based medicine could be feasible and incorporated into daily practice.

Feasibility of infusion pumps for continuous spinal administration of local anesthetics in post-operative pain therapy

BACKGROUND AND OBJECTIVES

For completion of perioperative care and for general ethical considerations, any intraoperatively used catheter technique should be utilizable for post-operative pain therapy. Continuous spinal anesthesia (CSA) is an established form of local anesthetic application. However, for its use in post-operative therapy, infusion pumps are required that are technically able to deliver low rates and are distinctive in design to avoid possible pump or medication swaps. Because of a lack of devices specifically designed for CSA, we investigated the potential deployability of infusion pumps for post-operative pain therapy via CSA microcatheters, which were originally designed and approved for different applications.

METHODS

The accuracy of infusion rates of three different pumps was measured in a liquor model environment. Furthermore, we investigated safety and user-friendliness by interviewing 30 anesthesiologists and 15 pain nurses.

RESULTS

Except for the first hour of infusion, all pumps provided comparable and adequate flow profiles. However, interviews revealed significant risk factors for all pumps in terms of swapping devices, lines or medications and misprogramming the units.

DISCUSSION

All pumps tested were technically able to deliver accurate flow rates; however, because the non-CSA-specific design involves the risk of medication overdosage and syringe swaps, none of the systems tested can be recommended for routine use in post-operative CSA, irrespective of the fact that it was an off-label application anyway. Therefore, to ensure patient safety, continuous spinal administration of local anesthetics via microcatheters is a questionable method of post-operative pain therapy as long as non-specific pumps are used.

Simulation-based medical education is no better than problem-based discussions and induces misjudgment in self-assessment

Simulation-based teaching (SBT) is increasingly used in medical education. As an alternative to other teaching methods there is a lack of evidence concerning its efficacy. The aim of this study was to evaluate the potency of SBT in anesthesia in comparison to problem-based discussion (PBD) with students in a randomized controlled setting. Thirty-three fourth-year medical students attending a curricular anesthesiology course were randomly allocated to either a session of SBT or a session of PBD on an emergency induction method. Ten days later all students underwent examination in a simulator. The performance of each student was evaluated by weighted tasks, established according to a modified Delphi process. Confidence and a multiple-choice questionnaire were additionally performed pre- and post-intervention. A total of 32 students completed the study. Participants in the SBT group presented with significantly higher self-assessment scores after the intervention than students in the PBD group. However, students in the SBT group achieved only slightly and statistically insignificantly higher scores in the theoretical and simulator examination (p > 0.05) with only a moderate effect size of d = 0.52. The current study demonstrates that both PBD and SBT lead to comparable short-term outcomes in theoretical knowledge and clinical skills. However, undesirably, SBT students overrated their anticipated clinical abilities and knowledge improvement.

[Scoliosis surgery in children from the viewpoint of anaesthesiology]

Anaesthesia for scoliosis surgery in children is a challenge for the paediatric anaesthesiologist. The large range of underlying pathologies causing deranged physiology in an inhomogeneous patient group ranging from neonates to adolescents necessitates diligent and individual preparation for each case. Due to the invasiveness of the operation demanding anaesthetic care is necessary. This review highlights current approaches to monitoring, anaesthetic regimen, positioning of the patient, blood conservation and transfusion, age-related pathophysiology, ventilation and postoperative pain therapy. The introduction of neurophysiologic spinal cord monitoring requires certain adaptations of the anaesthetic regimen to suit technological advances.

Protective effects of epidural analgesia on pulmonary complications after abdominal and thoracic surgery: a meta-analysis

OBJECTIVE

To review the impact of epidural vs systemic analgesia on postoperative pulmonary complications.

DATA SOURCES

Search of databases (1966 to March 2006) and bibliographies.

STUDY SELECTION

Inclusion criteria were randomized comparison of epidural vs systemic analgesia lasting 24 hours or longer postoperatively and reporting of pulmonary complications, lung function, or gas exchange. Fifty-eight trials (5904 patients) were included.

DATA EXTRACTION

Articles were reviewed and data extracted. Data were combined using fixed-effect and random-effects models.

DATA SYNTHESIS

The odds of pneumonia were decreased with epidural analgesia (odds ratio [OR], 0.54; 95% confidence interval [CI], 0.43-0.68), independent of site of surgery or catheter insertion, duration of analgesia, or regimen. The effect was weaker in trials that used patient-controlled analgesia in controls (OR, 0.64; 95% CI, 0.49-0.83) compared with trials that did not (OR, 0.30; 95% CI, 0.18-0.49) and in larger studies (OR, 0.62; 95% CI, 0.47-0.81) compared with smaller studies (OR, 0.37; 95% CI, 0.23-0.58). From 1971-2006, the incidence of pneumonia with epidural analgesia remained about 8% but decreased from 34% to 12% with systemic analgesia (P < .001); consequently, the relative benefit of epidural analgesia decreased also. Epidural analgesia reduced the need for prolonged ventilation or reintubation, improved lung function and blood oxygenation, and increased the risk of hypotension, urinary retention, and pruritus. Technical failures occurred in 7%.

CONCLUSION

Epidural analgesia protects against pneumonia following abdominal or thoracic surgery, although this beneficial effect has lessened over the last 35 years because of a decrease in the baseline risk.

Effectiveness and safety of postoperative pain management: a survey of 18 925 consecutive patients between 1998 and 2006 (2nd revision): a database analysis of prospectively raised data

BACKGROUND

Approximately 30-80% of postoperative patients complain about moderate to severe post-surgical pain, indicating that postoperative pain treatment is still a problem.

METHODS

We analysed prospectively collected data on patients in a university hospital receiving systemic and epidural patient-controlled analgesia and continuous peripheral nerve block (CPNB) documented by the acute pain service team in a computer-based system.

RESULTS

Of 18 925 patients visited in the postoperative period between 1998 and 2006, 14 223 patients received patient-controlled epidural analgesia (PCEA), 1591 i.v. patient-controlled analgesia (IV-PCA), 1737 continuous brachial plexus block, and 1374 continuous femoral/sciatic nerve block. Mean dynamic and resting pain scores (VAS 0-100) were significantly lower for peripheral or neuroaxial regional analgesia compared with patient-controlled systemic opioid analgesia (P<0.05). The risk of a symptomatic spinal mass lesion including epidural haematoma (0.02%; 1:4741) or epidural abscess (0.014%; 1:7142) after PCEA was 1:2857 (0.04%). Neurological complications after CPNB occurred in two patients who received interscalene brachial plexus block.

CONCLUSIONS

We demonstrated that PCEA, IV-PCA, and CPNB are safe and efficient. Although all of these treatment strategies provide effective analgesia, PCEA and CPNB provided superior pain relief compared with IV-PCA. We demonstrated that serious complications of analgesic techniques are rare but possibly disastrous necessitating a close supervision by an acute pain service. We found a low rate of adverse effects including hypotension and motor impairment and a low incidence of epidural haematoma for thoracic PCEA compared with lumbar PCEA.