Lego® bricks assisted training of the novice debriefers

Lego® Serious Play® is a guided workshop in which participants construct Lego creations to represent symbolic and metaphorical ideas in response to assignments. How to encourage inexperienced debriefers to concentrate on dialogue and communications strategies rather than engage in an unstructured debate on technical or behavioral abilities is one of the main challenges in training people to debrief a high-fidelity simulation session. We explore the use of Lego bricks in this study to build straightforward, standardised situations that debriefers in training can use to practice leading discussion. With this method, the different debriefing methodologies may be practiced focusing exclusively on method and dialogue, without getting involved or having to concentrate on the technical aspects.

Improving learning by playing with an app: The FantaTraining® experience with anesthesia trainees

Background: FantaTraining ^® is an app that simulates a football league. Each participant represents a team, and the game is played with the opposing team by answering a questionnaire. In the intervals between games, participants can practice by consulting the educational material (films, short texts, or slides) in the app. Various prizes are offered to the winners of the championship. In this study, we aimed to evaluate whether the use of the FantaTraining ^® app could improve the learning of anesthesia trainees registered in an online obstetric anesthesia course.

Methods: The study involved 282 trainees in anesthesia, from five Italian universities, registered in the Online Obstetric Anesthesia Course (OOAC) who were given the app. They were randomly allocated into two groups according to whether the app had been enabled to allow the participant to play the league (study group, n=137), or not (control group, n=145). All the trainees underwent entry and final tests, consisting of the same 40 multiple choice questions, respectively before and after completing the OOAC course.

Results: There were no differences in the scores obtained in the pre-course test between the groups. The mean score obtained in the final test was significantly greater than that obtained in the entry one in both groups (P<0.05) but the final test score obtained by the participants of the study group was significantly greater than that obtained by the control group. (P<0.001), regardless of the university of origin and year of specialization. Trainees stated that the app had helped their study, improving understanding and motivation, without increasing the intensity of study.

Conclusions: Using the FantaTraining ^® app greatly improved trainees’ final exam performance after the online obstetric anesthesia course. The FantaTraining ^® app seems a promising tool to improve learning outcomes by strengthening learning behaviors and attitudes towards learning.

Analysis of Epidural Waveform to Determine Correct Epidural Catheter Placement After CSE Labor Analgesia

Background

The epidural pressure is pulsatile and synchronized with arterial pulsations. Monitoring the epidural waveform has been suggested as a technique to reliably confirm the appropriate localization of the epidural catheter.

Objective

The aim of this study was to evaluate the sensitivity and specificity of the Computer Controlled Drug Delivery System with continuous pressure and waveform sensing technology (CCDDS) (CompuFlo^® CathCheck™) as an instrument to assess the correct placement of the catheter in the epidural space in parturients who have received combined spinal-epidural technique (CSE) for labor analgesia.

Methods

We enrolled 40 consecutive healthy patients undergoing CSE labor analgesia with successful analgesia. All the cases in which pulsatile waveforms in synchrony with heart rate were detected were considered to be true positives; all the cases in which there was the absence of pulsatile waves were followed up. If these patients had to eventually relocate or manipulate the epidural catheter, they were considered to be true negative. If the absence of pulse waves was observed in the presence of successful analgesia during labor, the patients were considered to be false negatives.

Results

Pulsatile waveforms synchronous with heart rate were observed in 33 cases associated with adequate analgesia. In 5 cases, the pulsatile waveforms were absent due to unilateral analgesia or catheter occlusion (true negatives). In 2 cases, the patients had effective analgesia but we were not able to observe a distinct pulsatile waveform. The pressure waveform analysis through the epidural catheter had a sensitivity of 95%, a positive predictive value of 100%, a specificity of 100% and a negative predictive value of 60%.

Conclusion

Pulsatile pressure waveform recording with CCDDS through the epidural catheter resulted in high sensitivity and positive predictive value which can help the proper placement of the epidural catheter.

The evolution of self and hetero-evaluation of repeated high fidelity simulation scenarios of post-partum hemorrhage with anesthesia trainees

This article was migrated. The article was marked as recommended. Introduction Evidence for self-assessment in medicine is controversialwith participants under-rating or overestimating their performance. It is also unclear whether this under or overestimation changes during the process of repeated simulation experience. In this study, the authors analyzed the evolution of the behavioral skills of anesthesia trainees during four consecutive standardized postpartum hemorrhages (PPH) high-fidelity simulation scenarios. They compared the self-assessment made by the leader himself and the assessment made by his teammates individually with the assessment made by two expert observers. Methods The authors enrolled forty anesthesia trainee volunteers and divided them into eight teams of five participants each. Each team enacted the same scenario of a patient with atonic PPH following vaginal delivery four times so that all the trainees, except the one assigned the leader's role, could rotate through the roles of anesthesia trainee, obstetrician, midwife, and nurse. The participants themselves and two expert observers, using standardized checklists and questionnaires, carried out an evaluation of the technical (diagnosis and treatment of atonic PPH) and behavioral (leadership, communication, situational awareness, and overall appraisal) skills evidenced in the scenarios. Results The authors noted a progressive improvement in the behavioral scores given to the leader by the examiners, his team, and himself, from the first to the fourth scenario. The scores given by the participants and by the leader himself were greater than those given by the independent observers in the first two scenarios but these differences were no longer significant during the last two scenarios. Discussion Participants overestimated their performances but this overestimation disappeared after the completion of the first two scenarios. The authors suggested that improving the skills of participants throughout the scenarios, most likely improved their metacognitive competence, helping them to better recognize their abilities.

Eye tracking metrics and leader's behavioral performance during a post-partum hemorrhage high-fidelity simulated scenario

BACKGROUND

The use of eye tracking in the simulated setting can help improve our understanding of what sources of information clinicians are using as they deliver routine patient care. The aim of this simulation study was to observe the differences, if any, between the eye tracking patterns of leaders who performed best in a simulated postpartum hemorrhage (PPH) high-fidelity scenario, in comparison with those who performed worst.

METHODS

Forty anesthesia trainees from the University of Catania Medical School were divided into eight teams, to enact four times the same scenario of a patient with postpartum hemorrhage following vaginal delivery. Trainees who were assigned the leader's role wore the eye tracking glasses during the scenario, and their behavioral skills were evaluated by two observers, who reviewed the video recordings of the scenarios using a standardized checklist. The leader's eye tracking metrics, extracted from 27 selected areas of interest (AOI), were recorded by a Tobii Pro Glasses 50 Hz wearable wireless eye tracker. Team performance was evaluated using a PPH checklist. After completion of the study, the leaders were divided into two groups, based on the scores they had received (High-Performance Leader group, HPL, and Low-Performance Leader group, LPL).

RESULTS

In the HPL group, the duration and number of fixations were greater, and the distribution of gaze was uniformly distributed among the various members of the team as compared with the LPL group (with the exception of the participant who performed the role of the obstetrician). The HPL group also looked both at the patient's face and established eye contact with their team members more often and for longer (P < .05). The team performance (PPH checklist) score was greater in the HPL group (P < .001). The LPL group had more and/or longer fixations of technical areas of interest (P < .05).

CONCLUSIONS

Our findings suggest that the leaders who perform the best distribute their gaze across all members of their team and establish direct eye contact. They also look longer at the patient's face and dwell less on areas that are more relevant to technical skills. In addition, the teams led by these best performing leaders fulfilled their clinical task better. The information provided by the eye behaviors of "better-performing physicians" may lay the foundation for the future development of both the assessment process and the educational tools used in simulation.

TRIAL REGISTRATION

Clinical.Trial.Gov ID n. NCT04395963 .

COVID-19 crisis, safe reopening of simulation centres and the new normal: food for thought

Background

The world is facing a massive burden from the coronavirus disease 2019 (COVID-19) pandemic. Governments took the extraordinary step of locking down their own countries to curb the spread of the coronavirus. After weeks of severe restrictions, countries have begun to relax their strict lockdown measures. However, reopening will not be back to normal.

Simulation facilities (SF) are training spaces that enable health professionals and students to learn skills and procedures in a safe and protected environment. Today’s clinicians and students have an expectation that simulation laboratories are part of lifelong healthcare education. There is great uncertainty about how COVID-19 will impact future training in SF. In particular, the delivery of training activities will benefit of adequate safety measures implemented for all individuals involved.

This paper discusses how to safely reopen SF in the post-lockdown phase.

Main body

The paper outlines 10 focus points and provides operational tips and recommendations consistent with current international guidelines to reopen SF safely in the post-lockdown phase. Considering a variety of national advices and regulations which describe initial measures for the reopening of workplaces as well as international public health recommendations, we provide points of reflection that can guide decision-makers and SF leaders on how to develop local approaches to specific challenges. The tips have been laid out taking also into account two main factors: (a) the SF audience, mainly consisting of undergraduate and postgraduate healthcare professionals, who might face exposure to COVID-19 infection, and (b) for many simulation-based activities, such as teamwork training, adequate physical distancing cannot be maintained.

Conclusions

The planning of future activities will have to be based not only on safety but also on flexibility principles.

Sharing common methods consistent with national and international health guidelines, while taking into account the specific characteristics of the different contexts and centres, will ultimately foster dissemination of good practices.

This article seeks to further the conversation. It is our hope that this manuscript will prompt research about the impact of such mitigation procedures and measures in different countries.

A year in review in Minerva Anestesiologica 2013

BACKGROUND

We organized a training program for oral fiber optic intubation (FOI) under conscious sedation. The efficacy of the program was evaluated by comparing the performances of experts and novices.

METHODS

The training procedure was divided into two sessions: a theoretical session on difficult airways, the fiber optic bronchoscope (FOB), remifentanil, topical anesthesia and patient interactions; and a session involving simulations of the FOI technique on dummies. For in vivo FOI, we enrolled patients requiring orotracheal intubation for elective surgery. Electrocardiograms, mean arterial pressure was railroaded over the fiberscope, and tracheal intubati6 and 7) FOIs, respectively, joined the study. To reach ±23 bpm, P=0.02), and RR was decreased (from 16±3 to 12±4 bpm, P<0.05). No differences were recorded between the experts and less-experienced anesthesiologists. The average duration of FOI was 3.3±2.0 min for experts and 4.2±2.4 min for novices (P=0.03). Procedures were successful in both groups, with patients in each group being equally satisfied with the procedures.

CONCLUSION

This study highlights the importance of a structured FOI training program, demonstrating that it is possible to learn to perform FOI proficiently by practicing on dummies.

Evaluation of a new training device to simulate the epidural and subarachnoid spaces for neuraxial anesthesia techniques

BACKGROUND

We are introducing a new epidural/spinal simulation unit to be used either as a part-task trainer to teach and learn regional anesthesia techniques or to be inserted in the manikin's back to allow reliable advanced simulation scenarios. The aim of this study was to determine if it may be a useful tool for training novice anesthesiologists in these procedures according to the evaluation performed by experienced anesthetists.

METHODS

Experienced anesthetists performed an epidural followed by a lumbar puncture procedure on the simulator model. Various aspects of both epidural and lumbar puncture insertions were scored for likeness to a real patient using a Likert scale.

RESULTS

Experienced anesthetists found the simulator to be life-like for almost all the aspects of epidural or spinal insertion and that the overall impression was that the simulator could provide a useful tool for training of epidural and spinal techniques. Almost all the examiners appreciated that this device contained layers representing the anatomical boundaries of each compartment, and the module can be added blood or sponge to the epidural compartment or water to the spinal compartment to challenge the trainee with more difficult procedure such as inadvertent dural or vascular puncture or difficult catheter insertion.

CONCLUSION

This device to be inserted in a full scale manikin may be a promising tool for training of neuraxial procedures. It could be also an essential component of more complex high fidelity scenarios when neuraxial anesthesia is one of the major learning goals.

Effect of sex and pregnancy on the potency of intrathecal bupivacaine: determination of ED₅₀ for motor block with the up-down sequential allocation method

BACKGROUND AND OBJECTIVE

The up-down sequential allocation model has been adapted to estimate the relative potency ratios for analgesia and motor block of the most commonly used epidural and intrathecal local anaesthetics. The aim of this study was to establish the median effective doses (ED50) for motor block with intrathecal bupivacaine and to estimate the ED50 ratios of these in male, female and pregnant patients.

METHODS

In this prospective, double-blind, parallel group, up-down sequential allocation study, we enrolled 30 male patients, 30 female, non-pregnant patients and 30 pregnant patients undergoing elective surgery under combined spinal-epidural anesthesia. The first two groups consisted of male or female patients undergoing elective lower limb surgery and the third group consisted of pregnant women at term (>36 and <41 weeks) with singleton pregnancies undergoing elective caesarean delivery. Patients received intrathecal isobaric bupivacaine 0.5% as part of the spinal-epidural anaesthesia technique. The initial dose was 4 mg and the testing interval was 1 mg with subsequent doses being determined by the outcome in the previous patient in the same group. The end point for efficacy was the occurrence of motor block in the lower limbs within 5 min.

RESULTS

There were significant (P < 0.0001) differences in ED50 estimates for motor block with intrathecal bupivacaine: 6.9 mg for men [95% confidence interval (CI), 5.2-8.6), 5.2 mg for women (95% CI, 4.5-5.8) and 3.4 mg for pregnant women (95% CI, 2.9-4.0).

CONCLUSION

We have demonstrated a hierarchy of potencies for motor block with intrathecal bupivacaine for men, women and pregnant women suggesting possible relevant differences owing to the effects of both sex and pregnancy.

The relative potencies for motor block after intrathecal ropivacaine, levobupivacaine, and bupivacaine

BACKGROUND

In this study, we sought to determine the median effective dose (ED50) for motor block of intrathecal ropivacaine, levobupivacaine, and bupivacaine and to define their motor-blocking potency ratios.

METHODS

We enrolled 104 parturients undergoing elective cesarean delivery with combined spinal-epidural anesthesia and randomized them to one of three groups to receive intrathecal 0.5% (wt/vol) ropivacaine, levobupivacaine, or bupivacaine. The initial dose was 4 mg, and the testing interval was set at 1 mg. Efficacy was determined by the occurrence of any motor block in either lower limb (modified Bromage and hip motor function scale) within 5 min after the spinal injection.

RESULTS

As assessed using up-down analysis, intrathecal ED50 for motor block was 5.79 mg for ropivacaine (95% CI 4.62-6.96), 4.83 mg for levobupivacaine (95% CI 4.35-5.32) and 3.44 mg for bupivacaine (95% CI 2.55-4.34) (P < 0.0007). The relative motor blocking potency ratios were ropivacaine/bupivacaine 0.59 (95% CI, 0.42-0.82), ropivacaine/levobupivacaine 0.83 (95% CI 0.64-1.09), and levobupivacaine/bupivacaine 0.71 (95% CI 0.51-0.98).

CONCLUSIONS

There is a clinical profile of potency for motor block for the pipecolylxylidines when administered spinally: low, intermediate, and high for ropivacaine, levobupivacaine, and bupivacaine, respectively.

Expectant fathers’ experience during labor with or without epidural analgesia

BACKGROUND

For men the worst aspect of childbirth is witnessing their partner in pain. The aim of this study was to investigate fathers' attitudes towards labor and delivery with and without epidural analgesia.

METHOD

The study was performed using a questionnaire that included yes/no, multiple choice or 6-point ordinal scale answers. Expectant fathers whose partners were nullipara between 36 and 38 weeks of gestation were recruited and the questionnaires were administered on the day after the birth. To investigate paternal anxiety during labor, the State part of the State-Trait Anxiety Inventory was used.

RESULTS

The questionnaire was completed by 243 fathers. Sixty percent (145) of the parturients received epidural analgesia and 40% (98) did not. Paternal characteristics were comparable. Fathers whose partners did not receive epidural analgesia felt their presence as troublesome and unnecessary (P<0.001). The presence of maternal epidural analgesia increased threefold paternal feelings of helpfulness and was associated with a greater involvement (P<0.001) and less anxiety and stress (P<0.001). Median (range) State-Trait Anxiety Inventory score was respectively 75 (50-80) and 30 (20-60) in fathers whose partners did not or did receive epidural analgesia (P<0.0001). Maternal analgesia greatly increased paternal satisfaction (P<0.0001).

CONCLUSION

Epidural analgesia reduces paternal anxiety and stress and increases paternal involvement, participation and satisfaction with the experience of childbirth.

Sensory assessment of epidural block for Caesarean section

BACKGROUND AND OBJECTIVE

Comparisons between the profile of regional blocks are difficult to make because different methods of testing are used among the studies. The aims of this prospective study were to describe the profile of epidural block by using a scoring system to evaluate the density of the block as assessed by the loss to pinprick, cold and touch sensation; to evaluate the extent of differential block and to determine whether there is any relationship between these three modalities of testing.

METHODS

We studied 85 parturients undergoing elective Caesarean delivery with epidural anaesthesia with pH adjusted lidocaine 2% with epinephrine 1:400,000 and sufentanil 10 microg. Assessment of sensory block was done in each dermatomal level bilaterally for loss to pinprick, cold and light touch sensation and the density of the block was evaluated on an ordinal scale every 5 min for 20 min and thereafter at 30 and 40 min.

RESULTS

We observed a two dermatomes differential block between the complete loss of cold sensation being cephalad and the complete loss of both pinprick and light touch sensation being caudal. We established a significant correlation between the scores used to assess the density of the block in the three different modalities by considering the pinprick score as reference (Spearman's rank correlation is 0.94, P<0.001 for pinprick vs. cold, 0.97, P<0.001 for pinprick vs. light touch).

CONCLUSIONS

By scoring the density of the block on an ordinal scale, knowing the level of the block to pinprick allows one to predict the level of the block to touch and vice versa.

Propofol and thiopentone for caesarean section revisited: maternal effects and neonatal outcome

In 56 women undergoing elective caesarean section, general anaesthesia was induced with either propofol 1% or thiopentone 2.5% followed by 50% nitrous oxide in oxygen and isoflurane 0.75% until delivery. In the thiopentone group the arterial pressure rose following tracheal intubation and skin incision, while in the propofol group there was a significant tendency to hypotension immediately following induction of anaesthesia. There were differences in electroencephalogram (EEG) between the groups, while laryngoscopy, intubation and surgical stimulation had no effect on EEG pattern. Recovery after anaesthesia did not differ between groups. None of the patients had recall of the intraoperative period, but 53% of patients induced with propofol showed signs of light anaesthesia between induction and delivery. Neonates in the propofol group had lower Apgar scores 1 min after birth than those in the thiopentone group, but these differences were no longer significant at 5 min. No differences were noted in neurobehavioural status at 1, 4 and 24 h.

Epidural analgesia for childbirth: effects of newer techniques on neonatal outcome

New low-dose, local anesthetic-opioid combinations, combined spinal epidural analgesia, and new anesthetic drugs, such as ropivacaine and levobupivacaine, have modified the anesthetic practice in obstetric labor analgesia. These new analgesic techniques have less or no neonatal effects when compared with traditional epidural labor analgesia. They also have less effect on mode of delivery, which may in turn affect neonatal outcome. The use of very diluted or low concentrations of local anesthetic solutions may reduce their placental passage and thus the possible subtle neonatal effects. Small doses of epidural or spinal opioids alone or combined with low doses of local anesthetics does not affect the well-being of the neonate at birth. When considering the neonatal outcome, combined spinal epidural analgesia is as well tolerated as low-dose epidural analgesia. Transient fetal heart rate changes have been described immediately after the administration of intrathecal or epidural opioids. Maternal hypotension may also occur at the onset of epidural analgesia. Whether the occurrence of transient fetal heart rate changes or maternal hypotension immediately after the epidural block may influence the neonatal outcome at birth needs verification.

Comparison of fentanyl with clonidine as adjuvants for epidural analgesia with 0.125% bupivacaine in the first stage of labor: a preliminary report

48 primiparae received epidural analgesia in labor with 10 ml of 0.125% bupivacaine with epinephrine 1:800 000, and then were divided in 4 equal groups (n = 12) to receive one of the following: 5 ml saline (B); 100 mug of fentanyl (BF); 150 microg of clonidine (BC); 75 microg of clonidine and 50 microg of fentanyl (BCF). All the patients had satisfactory analgesia. Onset was similar in the 4 groups but the duration of analgesia was significantly prolonged by the addition of either 100 microg of fentanyl or 150 microg of clonidine (respectively 89.8 min and 92.5 min vs 62.5 min) (P < 0.0001). The addition of both clonidine (75 microg) and fentanyl (50 microg) produced a considerably prolonged analgesia (177.5 min) (P < 0.0001). No episodes of bradycardia were observed. Hypotension, reversed by i.v. ephedrine, occurred in 2 patients of BCF group and in 1 patient of BF and BC groups. Only patients receiving fentanyl had pruritus. Both fentanyl and clonidine produced sedation, but both incidence and severity were greater with the mixture. No differences in neonatal outcome assessed by Apgar scores and NACS, were observed.

Minimum local analgesic doses of ropivacaine, levobupivacaine, and bupivacaine for intrathecal labor analgesia

BACKGROUND

Doses for intrathecal opioid-local anesthetic mixtures have been arbitrarily chosen. The aim of this study was to compare the analgesic efficacies of intrathecal ropivacaine, levobupivacaine, and bupivacaine for labor analgesia and to determine the analgesic potency ratios for these three drugs. For this purpose, the authors used the up-down sequential allocation model, which estimates the minimum local analgesic dose for intrathecal local anesthetic.

METHODS

Ninety-seven nulliparous term parturients in spontaneous labor, requesting combined spinal-epidural analgesia, were randomly allocated to one of three groups to receive 0.25% spinal ropivacaine, levobupivacaine, or bupivacaine. The initial dose of the local anesthetic drug was chosen to be 2.5 mg, and the testing interval was set at 0.25 mg. The subsequent doses were determined by the response of the previous parturient. Efficacy was accepted if the visual analog pain score decreased to 10 mm or less on a 100-mm scale within 30 min. The minimum local analgesic dose was calculated using the method of Dixon and Massey.

RESULTS

The intrathecal minimum local analgesic dose was 3.64 mg (95% confidence interval, 3.33-3.96 mg) for ropivacaine, 2.94 (2.73-3.16) mg for levobupivacaine, and 2.37 (2.17-2.58) mg for bupivacaine. The relative analgesic potency ratios were 0.65 (0.56-0.76) for ropivacaine:bupivacaine, 0.80 (0.70-0.92) for ropivacaine:levobupivacaine, and 0.81 (0.69-0.94) for levobupivacaine:bupivacaine. There were significant trends (P </= 0.021) for greater motor block with bupivacaine and levobupivacaine.

CONCLUSIONS

This study suggests a potency hierarchy of spinal bupivacaine > levobupivacaine > ropivacaine.

Epidural test dose with levobupivacaine and ropivacaine: determination of ED 50 motor block after spinal administration

BACKGROUND

When a test is required to detect a possible intrathecal catheter, many would seek to use the same local anaesthetic as that used for epidural analgesia. The rapid onset of inappropriate motor block after a local anaesthetic administered epidurally implies intrathecal spread. Because of claims of greater sensory-motor separation, or because of reduced potency compared with bupivacaine, the efficacy of the new local anaesthetics in intrathecal testing has been questioned. The aim of this study was to establish the feasibility of a test dose for an inadvertent intrathecal catheter using ropivacaine and levobupivacaine, and to establish the dose required.

METHODS

Sixty women undergoing elective Caesarean section with a combined spinal- epidural technique were enrolled into this prospective, double-blind sequential allocation study. The women were randomized to receive plain levobupivacaine 0.5% or ropivacaine 0.5% intrathecally. The dose was determined according to up-down sequential allocation. The end-point was any evidence of lower limb motor block within 5 min of injection.

RESULTS

The ED(50) motor block at 5 min was 4.8 mg (95% CI, 4.49, 5.28) for levobupivacaine and 5.9 mg (95% CI, 4.82, 6.98) for ropivacaine (95% CI difference, 0.052, 1.98) (P=0.04). The estimated ED(95) motor block was 5.9 mg (95% CI 5.19, 6.71) for levobupivacaine and 8.3 mg (95% CI, 6.30, 10.44) for ropivacaine. The potency ratio between the two drugs was 0.83 (95% CI, 0.69, 0.99).

CONCLUSIONS

Both local anaesthetics produce evidence of motor block within 5 min of intrathecal injection and could serve as tests of intrathecal administration. Derived ED(95) values suggest 10 mg doses should be effective, but this study did not measure predictive value. Ropivacaine is less potent for motor block than levobupivacaine by a factor of 0.83 (P<0.04).

The Relative Motor Blocking Potencies of Intrathecal Ropivacaine: Effects of Concentration

This study established the median effective dose (ED(50)) for motor block of intrathecal 1% and 0.1% ropivacaine and determined the effects of the concentration of the solution injected on the motor block obtained. We enrolled into this prospective, randomized, double-blind, sequential allocation study 54 parturients undergoing elective Cesarean delivery under combined spinal-epidural technique. Parturients were randomized to receive intrathecal ropivacaine either 1% or 0.1%. The initial dose was chosen to be 4 mg, with subsequent doses being determined by the response of the previous patient (testing interval, 1 mg). The occurrence of any motor block in either lower limb within 5 min from the intrathecal injection of the study solution was considered effective. The motor block at 5 min was 6.1 mg for 1% ropivacaine (95% confidence interval [CI], 5.1-7.1) and was 9.1 mg (95% CI, 7.8-10.3) for 0.1% ropivacaine (P = 0.0013; 95% CI difference, 1.3-4.7). The relative efficacy ratio of the 2 concentrations was 1.5 (95% CI difference, 1.2-1.9) in favor of the larger concentration. The ED(50) of spinal ropivacaine to produce motor block in pregnant patients was significantly influenced by the concentration of the local anesthetic, with dose requirements being increased by 50% for the smaller concentration.

IMPLICATIONS

The minimum local anesthetic dose for motor block with 0.1% ropivacaine is 50% larger than the 1% concentration with a relative efficacy ratio of 1.5. Our findings suggest that more diluted local anesthetic solutions determine less motor block, and this may be considered in ambulant laboring parturients.

Epidural levobupivacaine, ropivacaine and bupivacaine in combination with sufentanil in early labour: a randomized trial

BACKGROUND AND OBJECTIVE

To evaluate the efficacy, delay and duration of analgesia of three equianalgesic epidural doses of levobupivacaine, ropivacaine and bupivacaine during the first stage of labour.

METHODS

One hundred and twenty-nine healthy primigravida in spontaneous labour who requested epidural analgesia were enrolled in a randomized observer-blinded study. Parturients were allocated to receive epidural levobupivacaine 0.0625%, ropivacaine 0.1% or bupivacaine 0.06259%. Sufentanil 10 microg was added to all solutions; the total volume of epidural solution was 20 mL. Pain was measured using a 100 mm visual analogue pain scale immediately before the epidural block, and at 5, 10, 15, 20 and 30 min thereafter. Motor block was evaluated using a modified Bromage scoring system. The adequacy of motor function for ambulation was also evaluated. Delay of analgesia was the time interval between the injection of the solution and the first painless contraction. Duration of analgesia was the time from the first painless contraction to the parturients' requests for further analgesia.

RESULTS

Twelve parturients failed to complete the study. Eleven parturients had inadequate analgesia (four in Group Levobupivacaine, four in Group Ropivacaine and three in Group Bupivacaine; P > 0.05). Data was analysed from 34 parturients in Group Levobupivacaine, from 37 in Group Ropivacaine and from 35 in Group Bupivacaine. There were no differences in the delay of analgesia or in the number of parturients who were able to walk unaided. Levobupivacaine and ropivacaine produced more prolonged analgesia than bupivacaine (114 and 119 min, respectively, versus 89 min; P < 0.01).

CONCLUSIONS

During early labour, equipotent low concentrations of levobupivacaine, ropivacaine and bupivacaine, all with the addition of sufentanil 10 microg, produced similar pain relief and motor block, but levobupivacaine and ropivacaine produced a longer lasting analgesia. About 10% of parturients had inadequate analgesia with a single bolus of the tested solutions.

Minimum analgesic doses of fentanyl and sufentanil for epidural analgesia in the first stage of labor

In this study, we sought to determine the minimum analgesic doses and relative potencies of fentanyl and sufentanil when they are used as the sole epidural analgesic during the first stage of labor. Nulliparous parturients (n = 66) in spontaneous labor at term gestation and requesting epidural analgesia were enrolled into this prospective, double-blinded, randomized, sequential-allocation study. Each woman received fentanyl or sufentanil diluted with 0.9% wt/vol saline to a volume of 10 mL. The initial dose was arbitrarily chosen to be 125 microg for fentanyl and 25 microg for sufentanil, with subsequent doses being determined by the response of the previous patient (testing interval, 5 microg for fentanyl and 1 microg for sufentanil). Efficacy was accepted if the visual analog score decreased to < or =10 mm on a 100-mm scale within 30 min. The minimum analgesic dose or median effective dose was 21.1 microg (95% confidence interval [CI], 20.2-21.9 microg) for sufentanil and 124.2 microg (95% CI, 118.1-130.6 microg) for fentanyl (P < 0.0001). The sufentanil/fentanyl potency ratio was 5.9 (95% CI, 5.6-6.3). In conclusion, we have established the equivalent doses and relative potencies of fentanyl and sufentanil for epidural analgesia in the first stage of labor.

IMPLICATIONS

This study determined the minimum analgesic doses of fentanyl and sufentanil for epidural anesthesia in the first stage of labor. The sufentanil/fentanyl potency ratio was 5.9. This ratio may be used to establish the equivalent doses for fentanyl and sufentanil for epidural analgesia in labor.

Intraoperative fetal oxygen saturation during Caesarean section: general anaesthesia using sevoflurane with either 100% oxygen or 50% nitrous oxide in oxygen

BACKGROUND AND OBJECTIVE

The study was designed to evaluate whether the administration of sevoflurane in 100% oxygen for anaesthesia during Caesarean section would improve fetal and neonatal oxygenation compared with the administration of sevoflurane with 50% nitrous oxide in oxygen.

METHODS

The randomized, single-blind controlled study examined 24 mothers, ASA I-II, at term undergoing Caesarean section who were allocated to receive sevoflurane in either 100% oxygen (n = 13) or 50% nitrous oxide in oxygen (n= 11). General anaesthesia was induced in both groups with thiopental 4-5 mg kg(-1) followed by succinylcholine 1.5 mg kg(-1) to facilitate tracheal intubation. Parturients received sevoflurane given either in 100% O2 or in a 50:50 nitrous oxide and oxygen mixture, using 0.5-1.0% progressive incremental dosing up to 1.5-2.0 MAC. Non-invasive fetal oxygen saturation was measured between induction to delivery, and umbilical artery and vein PaO2 were evaluated at birth.

RESULTS

Intraoperative fetal oxygen saturation increased in all patients after maternal 100% oxygen administration (P < 0.01). Maternal hyperoxygenation significantly increased the umbilical vein and umbilical artery PaO2 and the umbilical artery SaO2 at birth (P < 0.0001).

CONCLUSIONS

Maternal hyperoxygenation significantly improves fetal as well as neonatal oxygenation.

Effect of epidural analgesia on the fetal heart rate

Fetal heart rate (FHR) changes occasionally follow the use of labor epidurals. Most studies of the phenomenon have focused on specific techniques, but similar timing and appearance suggest a common cause. Induction of analgesia may transiently alter the balance between factors encouraging and inhibiting uterine contractions with subsequent changes of FHR patterns. Regardless the etiology, these changes are transient and do not produce maternal or fetal morbidity. However, they must be promptly recognized and treated if necessary.

[Prehydratation and anaesthesia in obstetrics: state of the art]

All epidural or spinal techniques using local anaesthetics causes some degree of sympathetic blockade resulting in peripheral vasodilatation and possibly hypotension or reduction in cardiac output. In the practical clinic, administration of fluids intravenously prior spinal and epidural anaesthesia is required to prevent maternal hypotension and fetal hypoxia. We evaluated in this review the efficacy of volume preloading on the incidence of hypotension after spinal or epidural anaesthesia for caesarean delivery. Randomized controlled trials investigating volume preloading before the initiation of obstetric anaesthesia were sought by using MEDLINE (1966-2001). The primary outcome was the incidence of hypotension. Secondary outcomes included: ephedrine use, Apgar scores, umbilical cord pH values, and maternal nausea and vomiting. Crystalloid preload was inconsistent in preventing hypotension, whereas colloid appeared to be effective in all studies. A colloid solution, such as hydro-xyethyl starch (HES) might be preferable considering the capacity to stay intravasculary for a longer period. Few differences in fetal outcomes or maternal nausea and vomiting were reported. Increasing central blood volume by using colloid decreases the incidence of hypotension before loco-regional anaesthesia for cesarean delivery. Implications. We performed a review to determine whether fluid loading reduced the incidence of low blood pressure after spinal or epidural anaesthesia for caesarean delivery. Although no technique totally eliminates the occurrence of hypotension, colloid administration (starch or gelatin containing fluids) was the most effective.

[Motor block determination for the identification of accidental spinal injection of levobupivacaine: a study on the minimum efficient test-dose (ED50)]

BACKGROUND

The aim of this study was to determine the ED50 for the dose of levobupivacaine 0,5% that, if given intrathecally will not cause total spinal anesthesia but will give a reliable and reproducible clinical sign to differentiate intrathecal from epidural injection.

METHODS

Thirty women at term undergoing elective cesarean section under a combined spinal-epidural technique (CSE) were enrolled into this sequential allocation study. The dose in each test dose was determined by the response of the previous patient to the higher or lower dose in her test syringe, according to up-down sequential allocation. The exception to this was the first woman in each group, for whom the starting dose was chosen to be 4 mg. The end point was the occurrence of any motor block, in any side, within 5 minutes from intrathecal injection of the test dose. Test dose efficacy was assessed using a modified Bromage scale every minute for 5 minutes. The median effective dose of levobupivacaine was estimated from the up-down sequences using the formula of Dixon and Massey.

RESULTS

The MAD of the test dose for levobupivacaine was of 4,8 mg (4,4 to 5,2; 95% C.I.).

DISCUSSIONS

This study may help to determine the appropriate dose for a test dose for inadvertent spinal levobupivacaine.

[Levobupivacaine in obstetric analgesia and anaesthesia]

METHODS

Published studies, including abstracts, has been reviewed and summarized.

RESULTS

Studies in sheep have demonstrated no significant differences in pharmacokinetic and placental transfer of levobuvacaine when compared with bupivacaine. Clinical studies on cesarean section confirmed similar performance between these two drugs. No differences in onset time, sensory and motor block and efficacy of analgesia have been reported. Two multicentre studies on labor analgesia reported again similar analgesic efficacy with a trend toward less motor block in parturients receiving levobupivacaine.

CONCLUSIONS

This review has shown that levobupivacaine has a similar efficacy and a similar maternal fetal safety to that of bupivacaine. Further studies are needed to determine if the chemical properties of the new agent may influence the sensory and motor characteristics of the block.

Minimum analgesic dose of epidural sufentanil for first-stage labor analgesia: a comparison between spontaneous and prostaglandin-induced labors in nulliparous women

BACKGROUND

The aim of this prospective, double-blind, sequential allocation study was to compare the effects of spontaneous and prostaglandin-induced labor on the minimum analgesic dose of epidural sufentanil in the first stage of labor.

METHODS

Seventy healthy, nulliparous women, at more than 37 weeks' gestation with cervical dilatation from 2 to 4 cm, requesting epidural pain relief in labor were enrolled. The subjects were assigned to two different groups according to whether labor was spontaneous or induced with dinoprostone 0.5 mg. Parturients received 10 ml of the study solution through a lumbar epidural catheter. The initial dose was sufentanil 25 microg, and subsequent doses were determined by the response of the previous patient in the same group using up-down sequential allocation. The analgesic effectiveness was assessed using 100-mm visual analog pain scores. The up-down sequences were analyzed using the method of independent paired reversals and probit regression.

RESULTS

The minimum analgesic dose of sufentanil in spontaneous labor was 22.2 microg (95% CI: 19.6, 22.8) and 27.3 microg (95% CI: 23.8, 30.9) in induced labor. The minimum analgesic dose of sufentanil in induced labor was significantly greater (P = 0.0014) than that in spontaneous labor (95% CI difference: 2.9, 9.3) by a factor of 1.3 (95% CI: 1.1, 1.5).

CONCLUSION

Prostaglandin induction of labor produces a significantly greater analgesic requirement than does spontaneous labor.

A comparison between low-dose ropivacaine and bupivacaine at equianalgesic concentrations for epidural analgesia during the first stage of labor

The aim of this study was to evaluate the efficacy, onset and duration of analgesia of two equianalgesic epidural doses of ropivacaine and bupivacaine during the first stage of labor. The study included 190 healthy nulliparous parturients who presented spontaneous onset of labor and required epidural analgesia. They were divided randomly to receive epidural analgesia with an initial dose 0.10% ropivacaine or 0.0625% bupivacaine 20 mL both with the addition of 10 microg of sufentanil. There were no significant differences in onset time, quality of analgesia, maternal hypotension and ability to ambulate. Ropivacaine produced more prolonged analgesia then bupivacaine (89 vs 119 min;P<0.0003). The clinical value of this prolonged analgesia after the first dose needs further evaluation when a continuous infusion technique is used.

Relative potencies of bupivacaine and ropivacaine for analgesia in labour

We have used the technique of randomized, double-blind sequential allocation to compare the minimum local analgesic concentrations (MLAC) of epidural bupivacaine and ropivacaine for women in the first stage of labour. The test bolus was 20 ml of local anaesthetic solution. The concentration was determined by the response of the previous woman to a higher or lower concentration of local anaesthetic, according to up-down sequential allocation. Efficacy was assessed using a 100-mm visual analogue pain score (VAPS). The test solution had to achieve a VAPS of 10 mm or less to be judged effective. For bupivacaine, MLAC was 0.093 (95% CI 0.076-0.110)% w/v, and for ropivacaine, 0.156 (95% CI 0.136-0.176)%w/v (P < 0.0001, 95% CI difference 0.036-0.090). The analgesic potency of ropivacaine was 0.60 (0.47-0.75) relative to bupivacaine. Claims for reduced toxicity and motor block must be considered with differences in analgesic potency in mind.

Regional blocks for cesarean section

Recent researches in the field of regional anesthesia for cesarean section have focused on spinal anesthesia, including prophylaxis of maternal hypotension, the use of opioids to improve intra- and postoperative analgesia and the use of ropivacaine.

Minimum local analgesic concentration of extradural bupivacaine increases with progression of labour

We have used the technique of double-blind sequential allocation to quantify the minimum local analgesic concentration (MLAC) of extradural bupivacaine for women in early (median cervical dilatation 2 cm) and late (median cervical dilatation 5 cm) labour. The first bolus was 20 ml of the bupivacaine test solution. The concentration was determined by the response of the previous woman to a higher or lower concentration of bupivacaine according to up and down sequential allocation. Efficacy was assessed using a 100-mm visual analogue pain score (VAPS). The test solution had to achieve a VAPS of 10 mm or less to be judged effective. In early labour, the MLAC of bupivacaine was 0.048% w/v (95% confidence intervals (CI) 0.037-0.058% w/v), and 0.140% w/v (95% CI 0.132-0.150% w/v) in the late group. The MLAC of bupivacaine in late labour was greater by a factor of 2.9 (95% CI 2.7-3.2) compared with the MLAC in early labour (P < 0.0001, 95% CI difference 0.08-0.11). We conclude that advancing labour requires an increased concentration of extradural bupivacaine for pain relief.

Anatomy of the lumbar epidural region using magnetic resonance imaging: a study of dimensions and a comparison of two postures

Many techniques used to investigate the epidural region may alter the anatomy. Magnetic resonance imaging (MRI) has been introduced as a non-invasive diagnostic technique. The aim of this study was to investigate the anatomy of the lumbar epidural region using MRI, studying the morphology, the dimensions and the modification that may result from a change of position. Ten young, healthy female volunteers were studied to obtain results relevant to obstetric anesthesia. The following measurements were made: anterior epidural space (AES); posterior epidural space (PES); ligamenta flava; distance between the PES and the skin (S-ES); and interspace distance (ISD). All these distances were measured with the subject supine and the lumbar spine either in a neutral or a non-lordotic (flexed) position. The S-ES ranged from 2.7 to 8.1 cm. This distance was greater in the lower than in the upper lumbar segments. No differences were observed in AES, PES and ligamenta flava between the neutral and flexed positions. Flexion of the spine did not affect the S-ES but increased the ISD (P < 0.05). The S-ES at any lumbar segment or interspace and the thickness of ligamenta flava at the L2/3 interspace correlated significantly with body weight (respectively, P < 0.01 and P < 0.02). In conclusion, MRI may clearly reveal the anatomy of the epidural region. The circumferentially and metamerically segmented compartments of the epidural space were clearly noted and measured. Ligamenta flava seem to be thinner in younger than in older subjects. This may partly explain a reduced loss of resistance sometimes perceived in obstetric patients.

Maternal expectations and experiences of labour pain and analgesia: a multicentre study of nulliparous women

Six hospitals with large maternity units in five different European countries were involved in this multicentre study. At least 100 primiparae for each country were examined. All mothers received two standardized interviews, one during the last month of pregnancy, and one 24 h after delivery. Maternal expectations and experiences of pain, pain relief, and satisfaction with analgesia and childbirth were assessed by a 100 mm visual analogue scale (VAS). Almost all mothers were seen regularly by an obstetrician or a midwife during pregnancy, had prepared childbirth classes and received antenatal information on labor analgesia techniques. Differences between the five groups were noted in the level of education and socio-economic status. Maternal expectations of labor pain and the answers to the pre-delivery interview varied significantly between the centers, as did maternal knowledge, expectation and ultimate choice of analgesic technique. Generally speaking the level of maternal satisfaction with analgesia and childbirth experience was high; however, epidural analgesia was more effective than other methods of pain relief (P<0.0001). The most satisfied mothers were those who expected more pain, were satisfied with the analgesia received and had good pain relief after analgesia (P<0.001).

Alkalinization of local anesthetics. Which block, which local anesthetic?

BACKGROUND AND OBJECTIVES

A number of clinical studies have been performed in an attempt to establish the effects of alkalinization on potency of local anesthetics. Conflicting results were obtained probably because different studies used different methods as well as different definitions of the effects. To determine the efficacy of alkalinization using different local anesthetic solutions and different regional blocks, 180 patients were studied in a randomized, double-blind fashion. The local anesthetic solutions studied were bupivacaine, mepivacaine, and lidocaine; the regional blocks studied were epidural block, axillary brachial plexus block, and femoral and sciatic nerve block.

MATERIALS AND METHODS

In this study, 180 patients receiving epidural block (n = 60), sciatic and femoral nerve block (n = 60), and brachial plexus block (n = 60) were randomized to receive, in a double-blind fashion, a plain or a pH-adjusted solution of 2% mepivacaine, 2% lidocaine, or 0.5% bupivacaine. Onset of sensory analgesia, onset of maximum effect (peak effect or complete analgesia), duration of the block, onset, duration and density of motor block were evaluated using pinprick (Hollmen scale) and a 10-point decimal scale (Seow scale).

RESULTS

concerning epidural block, the alkalinization of the local anesthetic shortened significantly the onset of sensory analgesia in the dermatome corresponding to the lumbar interspace used for epidural puncture (L3-L4) and increased the spread of the epidural block in all the groups. The onset of sensory analgesia at L4 level ranged from 10 minutes for plain bupivacaine to 3 minutes for alkalinized lidocaine, whereas the onset at T10 level ranged from 16 minutes for plain bupivacaine and mepivacaine to 12.3 minutes for alkalinized lidocaine. The effects of alkalinization were more evident with lidocaine and bupivacaine. Concerning femoral and sciatic nerve blocks, a statistically significant shorter onset of sensory analgesia and motor block were observed with mepivacaine. Concerning brachial plexus axillary block, the effects of alkalinization were more evident with lidocaine.

CONCLUSIONS

Alkalinization produced the best results with lidocaine and bupivacaine for epidural block, with lidocaine for brachial plexus block, and with mepivacaine for sciatic and femoral nerve blocks.