Proficiency-based progression training: implementing a novel approach to training for epidural analgesia in labour.

BACKGROUND: Epidural insertion is a challenging anaesthetic procedural skill to learn and may require up to 75 attempts to achieve competency. Proficiency-based progression (PbP) training based on unambiguously defined metrics was associated with a 53% reduction in epidural failure rate. The aim of this observational study was to examine the feasibility of implementation of innovative PbP training for labour epidural insertion performed by novices in a busy tertiary hospital. METHODS: All trainees who were scheduled to commence their obstetric anaesthesia training were invited to participate. Novices undertook intensive PbP training with one-to-one supervision by an anaesthetist trained in PbP. Trainees proceeded to the clinical phase only after attaining the pre-defined proficiency benchmark. All subsequent attempts at labour epidural catheter placement were evaluated. RESULTS: All 12 novice trainees who were scheduled for their initial exposure to obstetric anaesthesia completed PbP training in epidural catheter insertion successfully. The average duration of the training courses was 70 (SD 11) min. Trainee characteristics were broadly similar. They performed a total of 180 labour epidural catheter placements with an overall epidural failure rate of 12.2% (22/180). The proportion of supervisor takeover was 6% (11/179). The incidence of complications was 4% (8/180) and difficulty in epidural catheter insertion due to patient factors was 16% (29/180). Patient satisfaction rates were 80% (satisfied or very satisfied), with 20% unsatisfied with their experience of epidural insertion. CONCLUSION: In our experience, PbP training in epidural placement is feasible within existing departmental resources in a busy tertiary teaching hospital setting.

Using psychometric ability to improve education in ultrasound-guided regional anaesthesia: a multicentre randomised controlled trial.

The learning curve for novices developing regional anaesthesia skills, such as real-time ultrasound-guided needle manipulation, may be affected by innate visuospatial ability, as this influences spatial cognition and motor co-ordination. We conducted a multinational randomised controlled trial to test if novices with low visuospatial ability would perform better at an ultrasound-guided needling task with deliberate practice training than with discovery learning. Visuospatial ability was evaluated using the mental rotations test-A. We recruited 140 medical students and randomly allocated them into low-ability control (discovery learning), low-ability intervention (received deliberate practice), high-ability control, and high-ability intervention groups. Primary outcome was the time taken to complete the needling task, and there was no significant difference between groups: median (IQR [range]) low-ability control 125 s (69-237 [43-600 s]); low-ability intervention 163 s (116-276 [44-600 s]); high-ability control 130 s (80-210 [41-384 s]); and high-ability intervention 177 s (113-285 [43-547 s]), p = 0.06. No difference was found using the global rating scale: mean (95%CI) low-ability control 53% (95%CI 46-60%); low-ability intervention 61% (95%CI 53-68%); high-ability control 63% (95%CI 56-70%); and high-ability intervention 66% (95%CI 60-72%), p = 0.05. For overall procedure pass/fail, the low-ability control group pass rate of 42% (14/33) was significantly less than the other three groups: low-ability intervention 69% (25/36); high-ability control 68% (25/37); and high-ability intervention 85% (29/34) p = 0.003. Further research is required to determine the role of visuospatial ability screening in training for ultrasound-guided needle skills.

Bleeding complications following peripheral regional anaesthesia in patients treated with anticoagulants or antiplatelet agents: A systematic review.

BACKGROUND: Patients on either antiplatelet or anticoagulant therapy may need procedures performed under peripheral nerve blocks in preference to general anaesthesia techniques. The risk of bleeding associated with peripheral nerve blocks under these circumstances remains unknown. This systematic review evaluates the incidence of bleeding complications following peripheral nerve blocks in patients receiving antiplatelet and/or anticoagulant medication. METHOD: All English, French and Spanish publications on peripheral nerve blocks in patients receiving antiplatelet and/or anticoagulant medication, from 1978 to 2018 from various sources including Pubmed, were reviewed. Publications on neuraxial anaesthesia (spinal or epidural) and eye blocks were excluded. RESULTS: Twenty-four articles were selected, including six observational studies and 18 case reports. Patients received antiplatelet agents only, in 4 studies, anticoagulants only in 14 studies, and both in 6 studies. In the observational studies, 80 bleeding complications (haematoma or minor bleeding at the puncture site) were identified following 9738 peripheral nerve blocks. Amongst case reports, 15 bleeding complications were noted following 50 peripheral nerve blocks. Bleeding complications were reported mostly with lumbar plexus blocks (1 requirement for blood transfusion, 1 catheter embolization, 1 surgical exploration and 1 death). The overall estimate of the incidence of bleeding complications was 0.82% (0.64%-1.0%). CONCLUSION: This systematic review found that bleeding complications following peripheral nerve blocks were rare in patients receiving antiplatelet and/or anticoagulant medication.

Fascial layers influence the spread of injectate during ultrasound-guided infraclavicular brachial plexus block: a cadaver study.

BACKGROUND: Fascial layers of the neurovascular sheath containing the brachial plexus influence distribution of local anaesthetic, hence increasing the risk of block failure when performing infraclavicular brachial plexus block (ICB). METHODS: Ultrasound-guided infraclavicular brachial plexus block was performed on cadavers using a single injection technique with dye (20-30 ml). After injection, we carried out consecutive dissection of the neurovascular bundle to study dye injectate spread and identify the presence of fascial layers. Ultrasound video images (scout scan and injection) and recordings of dissections were evaluated by independent experts (regional anaesthetists and anatomists). RESULTS: Well defined fascial layers were identified at dissection in seven out of 12 infraclavicular spaces studied. These fascial layers impeded the spread of dye injectate substantially in six cases and partially in one case. No fascial layers were identified at dissection in five cases, in each of which the spread of injectate was complete throughout the neurovascular bundle. The sensitivity and specificity of ultrasonography and haptic sensation for detection of fascial layers were poor. CONCLUSIONS: When fascial layers are present in the neurovascular sheath, they impede the spread of injectate during infraclavicular brachial plexus block. Ultrasound detection of these fascial layers is unreliable in cadavers. These findings support the use of greater volumes of injectate or a multiple injection technique when performing this block.

The effect of nefopam on lactation after caesarean section: a single-blind randomised trial.

BACKGROUND: Nefopam is a centrally acting analgesic which has a theoretical risk of stopping lactation due to its anticholinergic and dopaminergic effects. The aim of this study was to evaluate the effect of nefopam on lactation and to investigate potential adverse effects on newborns. METHODS: Seventy-two women, scheduled to undergo a caesarean delivery under spinal anaesthesia and wanting to breastfeed, were randomised to one of two groups: nefopam (20mg, six hourly) or paracetamol (1g, six hourly). In both groups, postoperative analgesia was supplemented with ketoprofen (50mg, six hourly) in conjunction with intrathecal morphine 0.1mg. The primary outcome was onset of lactation, estimated by weighing the newborns before and after feeding; by maternal perception of breast fullness and based on serum prolactin concentration 48hours postpartum. Secondary outcomes were neonatal adverse effects evaluated by neurobehavioural score at 12, 24, 48, and 72hours after birth. Statistical analyses were performed using Chi-squared, Fisher exact and Student t tests as appropriate. P<0.05 was considered statistically significant. RESULTS: The difference in the weight of the newborn before and after each feed, maternal perception of breast fullness and serum prolactin did not significantly differ between groups. The volume of artificial milk given to newborns of mothers in the nefopam group on days two and three was significantly greater than for the paracetamol group. Neurobehavioural scores were comparable at each time point. CONCLUSION: Nefopam does not appear to delay the onset of lactation or present any clear risk to the newborn.

Ultrasound-guided approach to nerves (direct vs. tangential) and the incidence of intraneural injection: a cadaveric study.

This study evaluated the incidence of nerve puncture and intraneural injection based on the needle approach to the nerve (direct vs. tangential). Two expert operators in regional anaesthesia performed in-plane ultrasound-guided nerve blocks (n = 158) at different levels of the brachial plexus in cadavers, aiming either directly for the nerve (n = 77) or tangentially inferior to the nerve (n = 81). After reaching the outer limit of the nerve, the needle was intentionally advanced approximately 1 mm in both approaches, and 0.2-0.5 ml of saline was injected. Each operator classified (in real time) the needle tip and injectate as intraneural or not. Video clips showing the final position of the needle and the injection were evaluated in the same manner by seven independent expert observers who were blinded to the aims of this study. In addition, 20 injections were performed with ink for histological evaluation. Intraneural injections of saline were observed by the operator in 58% (45/77) of cases using the direct approach and 12% (10/81) of cases using the tangential approach (p < 0.001). The independent observers agreed with the operator in a substantial number of cases (Cohen's kappa index 0.65). Histological studies showed intraneural spread in 83% (5/6) of cases using the direct approach and in 14% (2/14) of cases using the tangential approach (p = 0.007). No intrafascicular injections were observed. There was good agreement between the operators' assessment and subsequent histological evaluation (Cohen's kappa = 0.89). Simulation of an unintentional/accidental advancement of the needle 'beyond the edge' of the nerve suggests significantly increased risk of epineural perforation and intraneural injection when a direct approach to the nerve is used, compared with a tangential approach.

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.

Neuraxial anesthesia in patients with intracranial hypertension or cerebrospinal fluid shunting systems: what should the anesthetist know?

The management of patients with central nervous system disorders such as brain tumours, hydrocephalus, intracranial hypertension, or subarachnoid hemorrhage has improved in recent years resulting in increased life expectancy. Consequently, the prevalence of patients with increased intracranial pressure or cerebrospinal fluid shunting devices presenting for non-neurological procedures has increased. These patients commonly receive a general anesthetic, as the safety profile of neuraxial anesthesia in this clinical setting remains uncertain. This article reviews literature on neuraxial anesthesia in patients with intracranial hypertension or cerebrospinal fluid shunting systems. It describes current knowledge, exposes and weighs the real benefits and risks of this technique in this setting. It provides several scenarios and anesthetic options to help the practitioner with choosing a tailored approach in this specific population.

Unilateral permanent loss of vision after nefopam administration.

Acute glaucoma angle closure is a rare complication of anaesthesia and multimodal analgesia. However it is a medical emergency, hence any delay in its treatment may have catastrophic consequences. We present a case of postoperative glaucoma, which had evolved to permanent blindness. We also reviewed the French pharmacovigilance database between 1996 and 2006 and found four other cases of acute glaucoma angle closure in postoperative period possibly related to the administration of nefopam.

Effect of feedback content on novices' learning ultrasound guided interventional procedures.

BACKGROUND: Feedback, of various forms, is effective at improving performance of medical procedures in simulated and clinical settings. Our objectives were to compare the effects of two forms of feedback on i) novice learning of in-plane technique for ultrasound-guided interventional procedures and ii) to evaluate novice retention of skill 24 hours after a standard learning session. METHODS: Performance data were collected from 30 novices. All participants received training in the form of a standard training video. Participants were randomly allocated to one of three groups: Group C (Control) received no feedback; Group KR (Knowledge of Result) received feedback at the end of each series of tasks in the form of predefined performance intervals; and Group KP (Knowledge of Procedure) received feedback in the form of augmented error feedback. Each participant completed the series of tasks five times, using a standardized phantom model. Participants attempted to perform the same tasks 24 hours later using the same phantom. This performance was videotaped and assessed by two blinded assessors for predefined time and errors. RESULTS: All groups demonstrated significant learning effect in terms of imaging, needling and performance time. Error reduction was significant over time intervals measured and also in-between groups with significant difference between Control : KP (P<0.001) and KR: KP (P=0.001) but not between Control and KR groups. Marked and similar levels of skill attrition were identified in all three groups 24 hours after the learning phase CONCLUSION: When feedback was based on KP, novices acquired pre-defined skills more quickly and made fewer errors during the learning phase (compared with controls). When feedback content was based on KR novices acquired pre-defined skills more quickly but made similar numbers of errors during the learning phase (compared with controls). In conclusion, these findings should inform development of training and assessment programs for peripheral nerve blockade.

A clinical assessment tool for ultrasound-guided axillary brachial plexus block.

BACKGROUND: Competency in anesthesia traditionally has been determined subjectively in practice. Optimal training in procedural skills requires valid and reliable forms of assessment. The objective was to examine a procedure-specific clinical assessment tool for ultrasound-guided axillary brachial plexus block for inter-rater reliability and construct validity in a clinical setting. METHOD: This was a prospective observational study. Using prior work at our institution, the clinical assessment tool was developed consisting of a 63-point task-specific checklist and a global rating scale. The anesthesiologists were assigned to three groups based on prior experience of performing an axillary block: group 1 ('novices') < 10 procedures, group 2 ('intermediates') 50-80 procedures and group 3 ('experts') > 100 procedures. Each participant performed two consecutive blocks that were videotaped. Two blinded independent experts trained in the marking of the tool evaluated the videotapes. RESULTS: There were five participants per group. The inter-rater reliability between assessors was 0.842 and 0.795 for the checklist and global rating scale, respectively. There was a consistent difference between (each pair of) the three groups in terms of both the checklist and global rating scale (P < 0.05). For the checklist, expert vs. intermediate group P = 0.023, expert vs. novice group P < 0.001 and intermediate vs. novice group P = 0.019. For the global rating scale, expert vs. intermediate group P < 0.001, expert vs. novice group gave P < 0.001 and intermediate vs. novice group P = 0.023. CONCLUSION: The objective of task-specific checklist and global rating scale are reliable and valid measures of axillary block performance between different levels of expertise.

Perioperative anaphylaxis.

The incidence of immune-mediated anaphylaxis during anesthesia ranges from 1 in 10,000 to 1 in 20,000. Neuromuscular blocking agents are most frequently incriminated, followed by latex and antibiotics, although any drug or substance used may be a culprit. Diagnosis relies on tryptase measurements at the time of the reaction and skin tests, specific immunoglobulin E, or basophil activation assays. Treatment consists of rapid volume expansion and epinephrine administration titrated to symptom severity.

An investigation of potential genetic determinants of propofol requirements and recovery from anaesthesia.

BACKGROUND AND OBJECTIVE: The objectives of this study were, firstly, to characterize the inter-patient variability in the dose of propofol required to achieve a bispectral index <70 and 'time to eye opening' following propofol infusion and, secondly, to determine if the pharmacodynamic parameter 'time to achieve bispectral index <70' was influenced by genotype of the sex-linked drug receptor gene GABRE or if pharmacokinetic parameters such as clearance and 'time to eye opening' were influenced by the genotype of the metabolizing enzyme CYP2B6. METHODS: One hundred and fifty patients received a standardized anaesthetic. Apparent systemic clearance values were estimated. Correlation was sought between carriers of different CYP2B6 and GABRE genotypes and apparent systemic clearance, 'time to achieve bispectral index <70' and 'time to eye opening'. RESULTS: Propofol induction/emergence characteristics varied, with slow recovery times in a subset of males. Time to loss of verbal contact and time to bispectral index <70 varied 6.6- and 4.3-fold, respectively. At emergence, there was a 15.5- to 111-fold variability in the measured time intervals. Clearance varied from 9.1 to 55.8 mL min-1 kg-1. The CYP2B6 C1459T (R487C) genotype frequencies were TT 1%, TC 22% and CC 67%. The three major haplotypes of CYP2B6 (R487C, K262R and Q172H variants) were not significantly associated with time to eye opening or clearance. Clearance was similar in 487C carriers and 487RR genotypes. There was no statistically significant correlation between the four major haplotypes of GABRE variants investigated ([mRNA358]G/T, 20118C/T, 20326C/T and 20502 A/T) and the observed anaesthesia induction time. CONCLUSIONS: Great inter-patient variability exists in the dose of propofol required to achieve bispectral index <70, apparent systemic propofol clearance and time to eye opening. Common haplotypic differences at the CYP2B6 and GABRE genes do not appear to account for the majority of the observed inter-patient variability.

An objective assessment of nerve stimulators used for peripheral nerve blockade*.

Nerve stimulation is considered by many to be the current 'gold standard' for locating peripheral nerves. Thirteen nerve stimulators were subjected to a battery of tests performed by two independent observers under standardised conditions using a digital oscilloscope, a calibrated resistance and a novel scoring system. Individual scores were assigned for the signal waveform, current intensity, impulse duration, maximum load output and functionality of each nerve stimulator; the maximum score achievable was 20. A score of > or = 15/20 was achieved by six nerve stimulators: Stimuplex HNS 12 (B Braun); MultiStim Vario (Pajunk); Plexival (Medival, Vygon); MultiStim Sensor (Pajunk); Plexygon (Aryon, Vygon); Stimuplex HNS 11 (B Braun). Seven nerve stimulators scored < 15/20. Anaesthetists should be aware of the limitations of the nerve stimulator being used. Standardisation of features is desirable when manufacturing nerve stimulators.

Effects of levobupivacaine and ropivacaine on rat sciatic nerve blood flow.

BACKGROUND: Ischaemia is one of the causative mechanisms of peripheral nerve injury, a documented complication of regional anaesthesia. Local anaesthetics per se and/or vasopressor adjuvants may account for changes in peripheral nerve blood flow. The aim of this study was to test the effects of levobupivacaine and ropivacaine in a rat sciatic nerve model with respect to local blood flow and histopathological changes. METHODS: Forty-eight female Sprague-Dawley rats were anaesthetized for left sciatic nerve exposure. After baseline nerve blood flow measurement with a laser Doppler flowmeter, 0.2 ml of one of the following solutions was applied topically to the nerve in a random fashion: saline 0.9%; lidocaine 10 mg ml(-1); levobupivacaine 2.5 mg ml(-1); levobupivacaine 5 mg ml(-1); levobupivacaine 7.5 mg ml(-1); ropivacaine 2 mg ml(-1); ropivacaine 7.5 mg ml(-1); and ropivacaine 7.5 mg ml(-1) plus epinephrine 5 microg ml(-1); all in saline 0.9%. Nerve blood flow was evaluated at 5-min intervals up to 30 min after local application of anaesthetic solution. Three animals per group were killed for histological evaluation 48 h later. Multiple one-way analyses of variance followed by Scheffé's post hoc test was used for statistical analysis. P<0.05 was considered significant. RESULTS: Local anaesthetics at all concentrations tested caused significant reduction in nerve blood flow. The combination of ropivacaine 7.5 mg ml(-1) plus epinephrine did not reduce nerve blood flow to a greater extent than ropivacaine 7.5 mg ml(-1) alone. Low concentrations of levobupivacaine (2.5 and 5 mg ml(-1)) reduced nerve blood flow to the same extent as lidocaine 10 mg ml(-1). No significant histological changes were observed at 48 h. CONCLUSION: Despite acute reductions in peripheral nerve blood flow, significant histopathological changes were not observed in this rat sciatic nerve model after topical application of levobupivacaine and ropivacaine at concentrations relevant to clinical practice.