Acquisition of Competencies by Medical Students in Neurological Emergency Simulation Environments Using High Fidelity Patient Simulators.

The training of medical students demands practice of skills in scenarios as close as possible to real ones that on one hand ensure acquisition of competencies, and on the other, avoid putting patients at risk. This study shows the practicality of using high definition mannequins (SimMan 3G) in scenarios of first attention in neurological emergencies so that medical students at the Faculty of Medicine of the University of Salamanca could acquire specific and transversal competencies. The repetition of activities in simulation environments significantly facilitates the acquisition of competencies by groups of students (p < 00.5). The greatest achievements refer to skills whereas the competencies that demand greater integration of knowledge seem to need more time or new sessions. This is what happens with the competencies related to the initial diagnosis, the requesting of tests and therapeutic approaches, which demand greater theoretical knowledge.

[Questionnaire on the anaesthesiology treatment of patients subjected to posterior fossa neurosurgery]. / Encuesta sobre el tratamiento anestesiológico de los pacientes sometidos a neurocirugía de fosa posterior.

OBJECTIVES: To find out, by means of a questionnaire, the procedures used by Spanish anaesthetists in peri-operative management of patients subjected to neurosurgery of the posterior cranial fossa. MATERIAL AND METHODS: A closed-question type questionnaire was sent to Anaesthesiology Departments with a Neurosurgery Department on the participation of anaesthetists in the peri-operative treatment of patients subjected posterior fossa surgery. RESULTS: The questionnaire was completed by 42 (57.5%) of the 73 national public hospitals with a Neurosurgery Department. The posterior fossa surgery was performed in the sitting position in 36 hospitals, although it was less frequently used than the lateral decubitus or prone decubitus position. There was little specific neurological monitoring, as well as little use of precordial and/or transcranial Doppler for detecting vascular air embolism. Nitrous oxide was used in less than 10% of the centres, and 15% avoided neuromuscular block when neurophysiological monitoring was used during the surgery. Cardiovascular problems were mentioned as being the most frequent in 29% of the centres, while in the post-operative period the most common complications were, cranial nerve déficit, airway oedema (23%), and post-operative vomiting (47%). CONCLUSIONS: The results obtained from the questionnaire showed that the sitting position was less used than the prone position in posterior fossa surgery, and that neurophysiological monitoring is during surgery is hardly used.

[Vagus nerve stimulation for the treatment of refractory epilepsy. State of the art]. / Estimulación eléctrica vagal en el tratamiento de la epilepsia rebelde. Situación actual.

The vagus nerve stimulation (VNS) therapy is a new neurostimulation technique used for treating pharmacoresistant epilepsy. It can be considered an effective and safe alternative for the treatment of refractory epilepsy patients. In the present review, we describe the surgical implantation technique, its indications and results achieved until now. We will also summarize the possible mechanisms of action of VNS therapy. Finally, we will comment on the difficulties and inconveniences that did not allow this antiepileptic surgical technique to become more widely used.

Estimulación eléctrica vagal en el tratamiento de la epilepsia rebelde. Situaciónactual / Vagus nerve stimulation for the treatment of refractory epilepsy. State of the art

La estimulación intermitente vagal es una técnica de neuroestimulación de reciente incorporación en el tratamiento de pacientes con epilepsia refractaria al tratamiento farmacológico convencional. Hasta el momentopresente y, a pesar de algunos resultados dispares, se ha mostrado como una alternativa eficaz y segura en el tratamiento de estos pacientes. El presente trabajo de revisión pretende acercar la técnica quirúrgica de implantación, comentar las indicaciones y resultados obtenidos hasta la actualidad, y profundizar en los posibles mecanismos de acción de este tipo de estimulación,para finalmente realizar una aproximación crítica a la misma, intentando puntualizar cúales han sido los problemas e inconvenientes que han impedido la utilización generalizada de esta alternativa quirúrgica antiepiléptica (AU)

The vagus nerve stimulation (VNS) therapy is a new neurostimulation technique used for treating pharmacoresistant epilepsy. It can be considered an effective and safe alternative for the treatment of refractory epilepsy patients. In the present review, we describe the surgical implantation technique, its indications and results achieved until now. We will also summarize the possible mechanisms of action of VNS therapy. Finally, we will comment on the difficulties and inconvenients that did not allow this antiepileptic surgical technique to become more widely used (AU)

[Effect of combination therapy with hypothermia, magnesium and tirilazad in an experimental model of diffuse cerebral ischemia]. / Efecto de la hipotermia combinada con magnesio y tirilazad en un modelo experimental de isquemia cerebral difusa*

OBJECTIVE: To determine the grade of neuroprotection of combined treatment with moderate hypothermia, tirilazad and magnesium sulfate. Cerebral ischemia is one of the problems of great interest at present, with limited therapeutic measures. Hypothermia, one of the more efficient measures, together with neuroprotector pharmaceuticals, could be a valid alternative. DESIGN: Experimental study with a control group and two levels of application of therapeutic measures. CONTEXT: Experimental laboratory of the Medicine Faculty. PARTICIPANTS AND METHOD: Twenty-eight Wistar rats underwent global cerebral ischemia of 10 minutes duration by the combination of bilateral carotid clamping and controlled hypotension (mean arterial pressure: 45 mmHg). Three groups were used: group I, normothermia maintenance; group II, moderate hypothermia (32-33 degrees C) for 2 hours; group III, hypothermia and administration of tirilazad mesylate and magnesium sulfate during the reperfusion and two hours after ischemia. The animals were sacrificed at 7 days and, after processing the tissue, the neurons preserved in layer CA1 of the hippocampus were counted. RESULTS: There is a significantly greater neuronal preservation in group III with regard to group I (55.4 +/- 5.1 versus 38.7 +/- 8.8, p < 0.0001). If we compare groups II and III, significant differences are only obtained on the right side and in the hippocampus considered globally, favoring the group with hypothermia and drugs. When groups I and II are compared there are no significant differences. CONCLUSIONS: Association of moderate hypothermia, magnesium sulfate and tirilazad mesylate in the experimental model of transitory global ischemia used is confirmed as an effective neuroprotector measure, surpassing the degree of neuronal preservation of hypothermia alone.

Cost-effectiveness of three combinations of antiemetics in the prevention of postoperative nausea and vomiting.

BACKGROUND: This study compares the cost-effectiveness of three combinations of antiemetics in the prevention of postoperative nausea and vomiting (PONV). METHODS: We conducted a prospective, double-blind study. Ninety ASA I-II females, 18-65 yr, undergoing general anaesthesia for major gynaecological surgery, with standardized postoperative analgesia (intrathecal 0.2 mg plus i.v. PCA morphine), were randomly assigned to receive: ondansetron 4 mg plus droperidol 1.25 mg after induction and droperidol 1.25 mg 12 h later (Group 1); dexamethasone 8 mg plus droperidol 1.25 mg after induction and droperidol 1.25 mg 12 h later (Group 2); ondansetron 4 mg plus dexamethasone 8 mg after induction and placebo 12 h later (Group 3). A decision analysis tree was used to divide each group into nine mutually exclusive subgroups, depending on the incidence of PONV, need for rescue therapy, side effects and their treatment. Direct cost and probabilities were calculated for each subgroup, then a cost-effectiveness analysis was conducted from the hospital point of view. RESULTS: Groups 1 and 3 were more effective (80 and 70%) than Group 2 (40%, P=0.004) in preventing PONV but also more expensive. Compared with Group 2, the incremental cost per extra patient without PONV was euro;6.99 (95% CI, -1.26 to 36.57) for Group 1 and euro;13.55 (95% CI, 0.89-132.90) for Group 3. CONCLUSION: Ondansetron+droperidol is cheaper and at least as effective as ondansetron+ dexamethasone, and it is more effective than dexamethasone+droperidol with a reasonable extra cost.

A comparison of three antiemetic combinations for the prevention of postoperative nausea and vomiting.

UNLABELLED: In this study we compared the efficacy and safety of three antiemetic combinations in the prevention of postoperative nausea and vomiting (PONV). Ninety ASA status I-II women, aged 18-65 yr, undergoing general anesthesia for major gynecological surgery, were included in a prospective, randomized, double-blinded study. A standardized anesthetic technique and postoperative analgesia (intrathecal morphine plus IV patient-controlled analgesia (PCA) with morphine) were used in all patients. Patients were randomly assigned to receive ondansetron 4 mg plus droperidol 1.25 mg after the induction of anesthesia and droperidol 1.25 mg 12 h later (Group 1, n = 30), dexamethasone 8 mg plus droperidol 1.25 mg after the induction of anesthesia and droperidol 1.25 mg 12 h later (Group 2, n = 30), or ondansetron 4 mg plus dexamethasone 8 mg after the induction of anesthesia and placebo 12 h later (Group 3, n = 30). A complete response, defined as no PONV in 48 h, occurred in 80% of patients in Group 1, 70% in Group 3, and 40% in Group 2 (P = 0.004 versus Groups 1 and 3). The incidences of side effects and other variables that could modify the incidence of PONV were similar among groups. In conclusion, ondansetron, in combination with droperidol or dexamethasone, is more effective than dexamethasone in combination with droperidol in women undergoing general anesthesia for major gynecological surgery with intrathecal morphine plus IV PCA with morphine for postoperative analgesia. IMPLICATIONS: The combination of ondansetron plus dexamethasone or droperidol was significantly better than the combination of dexamethasone plus droperidol in the prophylaxis of postoperative nausea and vomiting in women undergoing general anesthesia for major gynecological surgery, with intrathecal and IV morphine (patient-controlled analgesia) for management of postoperative pain.

[Efficacy of 0.1 mg of subarachnoid morphine combined with bupivacaine on postoperative analgesia in total hip arthroplasty]. / Eficacia de 0,1 mg de morfina subaracnoidea asociada a la bupivacaína sobre la analgesia postoperatoria en la artroplastia total de cadera.

OBJECTIVES: To analyze the analgesic efficacy, safety and side effects of subarachnoid morphine (0.1 mg) with bupivacaine in patients undergoing total hip arthroplasty. PATIENTS AND METHODS: Thirty patients scheduled for total hip replacement under spinal anesthesia with bupivacaine were randomly assigned to two groups according to whether local anesthetic with 0.1 mg subarachnoid morphine was also provided or not (group M [n = 15] and group S n = 15[, respectively). Top-up analgesia with morphine was available through a patient-controlled device. Postoperative pain was assessed on a visual analogue scale (VAS) and consumption of intravenous morphine in the first 48 hours after surgery was recorded. RESULTS: VAS scores (mean +/- SD) were significantly lower in the first six hours in group M, but no differences between the two groups were observed thereafter. Total consumption of morphine at 48 hours was much lower in group M (6.80 +/- 7.74 mg) than in group S (31.38 +/- 13.17 mg). The incidence of nausea was high in both groups (46%). Slight pruritus affected 26.6% of patients in group M. Urinary retention necessitating temporary placement of a catheter was observed only in group M, where the incidence was 35.7%. No cases of respiratory depression occurred. Drowsiness was observed in 26.6% of patients in group S in comparison with 6.6% in group M. CONCLUSIONS: Combining 0.1 mg morphine and bupivacaine for total spinal anesthesia during hip arthroplasty significantly decreased the consumption of intravenous morphine during the first 48 hours after surgery. No respiratory depression occurred and the only side effects were urinary retention and mild pruritus and drowsiness.

Management of intractable spasticity of supraspinal origin by chronic cervical intrathecal infusion of baclofen.

Today it is accepted that chronic infusion of baclofen produces significant relaxation and drastic reduction of spasms, amelioration of cramping pain and improvement of sphincter functions in spasticity of spinal cord origin. Based on these results our group had the opportunity of treating 11 cases with refractory spasticity and dystonic symptoms due to central damage caused by head injury in 8 cases and to cerebral palsy in 3 using cervical intrathecal infusion of baclofen. During the trial period with percutaneous intrathecal infusion of a daily bolus of 12.5-75 micrograms of baclofen through a reservoir, improvement of mentation and speech conditions, marked improvement of dystonic and abnormal movements of the upper limbs and trunk and a notable reduction of hypertonia were observed in all cases, which led to a better performance of motor activities in skilled acts and transfer. With these preliminary results in mind, in all cases the previous cervical subarachnoid catheter was attached to a programmable pump that infused a daily total dose varying from 100 to 190 micrograms of baclofen in a continuous or multistep complex mode. After a mean follow-up of 21 months previous results were long-lasting. Neither overdose side effects nor malfunction of the system were observed.

High-cervical spinal cord electrical stimulation in brain low perfusion syndromes: experimental basis and preliminary clinical report.

Previous studies of our group showed that C1-C2 spinal cord stimulation increases carotid and brain blood flow in normal conditions in the goat and dog and it has a beneficial vasomotor effect in a model of vasospasm in the rat. For further clinical application it seemed rational to investigate the possible vascular changes mediated by this technique in experimental brain infarction. To this aim, 45 New Zealand rabbits were used. Brain infarction was produced by bilateral carotid ligation in 15, unilateral microcoagulation of the middle cerebral artery in 15 and by microcoagulation of the vertebral artery at the craniocervical junction in the other 15. One week later, following daily clinical scoring and cortical and posterior fossa blood flow readings by laser Doppler, a period of 120 min of right C1-C2 spinal cord electric stimulation was performed. A mean of 27% increase in previous blood flow recordings was obtained at the right hemisphere and a mean of 32% in the posterior fossa. This procedure was used in 10 patients presenting with various cerebral low perfusion syndromes. Though not constant, an increase in alertness, retention, speech, emotional lability and performance in skilled acts was achieved. No MR changes were observed, though SPECT readings showed an increase in blood flow in the penumbral perilesional area.

Chronic intrathecal baclofen administration in severe spasticity.

On the basis of previous experimental and clinical studies, 14 patients with severe spasticity due to central or spinal cord damage, resistant to all conservative treatments, were selected after a percutaneous trial period for chronic intrathecal baclofen infusion by programmable pumps. The agent was delivered at C4 in quadriplegic patients or in cases with central spasticity and in the neighbouring areas on the affected segments in paraplegic patients. The daily baclofen dose varied from 25 to 260 micrograms and was infused in a bolus, continuously infused or both combined according to the results during the trial period. After a mean follow-up period of 11 months, constant decrease of rigidity, absence of spasms, improvement of bladder function, cramping pain remission, and moderate improvement in walking capacity and transfer activities were usually observed. Neither complications nor side effects were noted.

Role of vasoactive substances in the segmentary vasomotor response following spinal cord stimulation. An experimental study.

It is presumed today that spinal cord stimulation induces local delivery of vasoactive substances, such as prostacyclins, histamine, substance P, and vasoactive neuropeptides, in the perivascular environment and the vascular wall to mediate the segmental vasodilator response. To investigate this mechanism, 9 dogs were subjected to low thoracic spinal cord stimulation. Venous and arterial blood samples from the paraesthesic area in the lower limbs were obtained before and 120 min after stimulation to measure changes in the plasma concentration of vasoactive intestinal peptide, substance P, and histamine. The results were compared with those obtained from vessels of the upper limbs. Blood flow changes following stimulation were recorded by electromagnetic flowmeters. Local arterial vasoactive intestinal peptide showed a mean increase of 33% after 60 min of stimulation. Changes concerning substance P were inconclusive. Local arterial and venous histamine concentrations increased 26 and 29%, respectively, after 60 min of stimulation.

Spinal cord stimulation in deafferentation pain.

Spinal cord stimulation (SCS) was used in 49 cases to control resistant deafferentation pain resulting from causalgia, phantom limb, plexus and nerve root avulsion, postherpetic neuralgia, reflex sympathetic dystrophy and amputation. In all cases, one or two standard percutaneous leads were introduced into the epidural space and manipulated until the spinal segment at which external stimulation provoked paresthesic sensation in the painful area. Two weeks of external stimulation trial was used to determine the efficiency of the system. Pulse width of 0.1-0.2 ms, a rate of 80-120 cps and amplitude to low paresthesia threshold were programmed as electric parameters. In 36 out of the 49 tested cases showing a positive response to percutaneous SCS, the device was permanently implanted. After a mean follow-up of 5.5 years, 57% of patients had satisfactory pain relief (over 75%). Side effects were limited to dislodgement of the electrode in 1 case and wire extrusion in another, both requiring replacement of the stimulator.

Critical approach to intrastriatal medullary adrenal implants via open surgery in parkinsonism. Case report.

Encouraged by the recent reports on the beneficial effects obtained with open transplantation of autologous adrenal medullary grafts into striatal structures in case with resistent Parkinson's disease, our team used this procedure in a 63-year-old man presenting with severe bradykinesia and rigidity resistent to all pharmacological attempts. In this case through a laparotomy the right adrenal gland was removed and stored in oxygenated Collins and bicarbonated Ringer solution mixtures while a F2 transventricular approach to the head of the caudatum was done. With the surgical microscope the medullary part of the adrenal gland was dissected and four pieces of mm3 of tissue selected, implanting them in a bed previously carved in the caudatum. Endocrinologic and hydroelectrolytic problems appeared during the immediate postoperative period. In the following 5 months no clinical benefit nor electroneurophysiological changes were observed.

Cerebral and carotid haemodynamic changes following cervical spinal cord stimulation. An experimental study.

Since it is accepted that spinal cord stimulation may produce segmentary vasodilation, it is presumable that when applied in the high cervical segments some carotid and cerebral blood flow changes can be expected. Following this assumption, 25 dogs and 25 goats were used. Under routine experimental conditions a C 7 laminectomy was performed in these animals and a bipolar lead introduced and manipulated in the epidural space till the right C 2 segment. Right common and internal carotid arteries of the dogs were isolated and electromagnetics probes placed for continuous monitoring of blood flow changes. Right internal maxillary artery was isolated and its branches ligated for flowmetry of hemispheric blood flow in the goat. 131I antipyrine also studied to control regional cerebral blood flow changes. Arterial pressure and blood gasometry were periodically determined to avoid masking results. Pulse width of 0.1 to 0.2 msec, 80 to 120 cps and amplitude to muscle contraction threshold at low rate were used as electrical parameters. After stimulation common and internal carotid blood flow increased with a mean of 60% and hemispheric blood flow with a mean of 55% according to flowmetry findings. Iodoantipyrine studies showed an average increase of 35%. These changes were not modified by atropine, morphine and naloxone and partially blocked by indomethacin, cimetidine and propanolol.

Use of intrathecal baclofen administered by programmable infusion pumps in resistent spasticity.

On the basis of previous experimental and clinical studies patients with severe spasticity due to spinal cord damage from multiple sclerosis in 8 cases and postraumatic paraplegia in 6 and resistent to all conservative treatments were selected for a trial with morphine and baclofen administered intrathecally through a catheter placed in the spinal subarachnoid space rostral to the affected segments and attached to a subcutaneous reservoir. Whereas morphine single injection did not show any benefit, baclofen bolus injection 30 to 60 micrograms, revealed a marked decrease of spasticity and associated symptoms in 8 cases. After checking the clinical effect during 3 weeks and changes in electroneurophysiological studies and bladder manometry the catheter was attached to a subcutaneous programmable pump able to be refilled percutaneously and administered baclofen continuously or more often following a multistep complex programme in total doses of 90 to 150 micrograms per day. After a mean follow-up of 5 months all cases showed an absence of spasms and pain, a notable improvement for bettering of sphincter functions and a marked muscle relaxation that improves motor capacity, leading to increased ambulation or mobility. Neither complications nor side-effects were observed.

Local pathological findings in experimental dorsal root entry zone lesions performed by mechanical section, laser and radiofrequency. A comparative study.

Dorsal root entry zone lesions are nowadays accepted as a first choice of treatment to alleviate certain types of chronic pain though it is still controversial to decide proper procedure for lesioning. Based on this last argument in 15 mongrel dogs different types of lesions using mechanical microsection, radiofrequency and laser were done. Under general anaesthesia a C-3 to C-7 laminectomy was performed in all animals and after open the dura mater the posterior nerve rootlets and posterolateral sulcus were identified using magnification. In 5 dogs, a longitudinal 1 mm deep incision from C-4 to C-6 spinal cord segments coinciding with the sulcus was carried out with a microknife; in other 5, a sequence of thermocoagulations produced by a radiofrequency current lower than 35 mA was done at same places and level with intervals of 2 mm; and in the rest of animals, an alike incision in depth, location and level was realised by carbon dioxide laser. Four days and three months after lesioning 2 and 3 animals of each group were sacrificed and spinal cord specimens submitted for histological and ultrastructural studies. Low-power microscopic examination showed that all lesioning methods were able to produce a reasonable well delimited necrotic area involving the whole dorsal root entry zone structures, slightly more diffuse with the laser. Acute perilesional changes as well as chronic ones were nevertheless more evident in mechanical and radiofrequency lesions, over all regarding oedema, perivascular haemorrhage, intraluminal thrombosis and ischaemic alterations.

Dorsal root entry zone lesion versus spinal cord stimulation in the management of pain from brachial plexus avulsion.

In six patients with total or partial brachial plexus avulsion, spinal cord stimulation was tried as pain treatment. Two patients had had amputation of the arm and suffered from phantom limb and stump pain. After a mean follow-up of 14 months two patients were painfree, one had partial relief and required analgesics and in three patients there was no effect. In eleven patients, including the three patients in whom spinal cord stimulation had failed to produce a long-lasting pain relief, dorsal root entry zone (DREZ) lesions were performed. At early follow-ups all these patients reported substantial pain relief, but after a mean follow-up of 17 months the results were less favorable: Three patients were pain-free, three had a marked improvement and five had recurrence of the original pain. Neither of the two methods of treatment produced any serious side-effects or permanent sequelae.

High-frequency cervical spinal cord stimulation in spasticity and motor disorders.

High frequency stimulation of the cervical spinal cord was used in an attempt to moderate motor disorders in 10 patients, 5 spastics, 3 dystonics and 2 with spasmodic torticollis. Through a C4 flavectomy a quadripolar flat electrode was introduced into the epidural space, placing the first terminal at C2. Electrical parameters for stimulation were established at 0.05-0.10 msec pulse width, rate of 200-1,400 Hz and amplitude to paresthesia threshold. Stimulation was delivered 1 hour on and 1 hour off during daytime. Subjective, clinical and/or neurophysiological initial improvement were initially observed in 9 cases, in which the stimulation system was permanently implanted. After a mean follow-up of 41.4 months all patients but one had a clinical and neurophysiological condition almost similar to the prestimulation one. To investigate the effect of the so-called high-frequency stimulation on the nervous system, 9 dogs were implanted following the same surgical technique and stimulated with analogous electrical parameters than in human practice. After follow-up of 8 months the pathological studies of the animals did not show any local or suprasegmental alterations on nervous structures except a local huge dural scarring reaction.

Stereotactic evacuation and local administration in intracerebral haematomas. A comparative study.

Based on current controversies on optimal treatment for spontaneous intracerebral haematomas, chronic experiments to investigate the validity of open surgery, stereotactic evacuation and local urokinase administration in these lesions were performed in 52 dogs. Under general anesthesia diverse volumes of autologous blood were intracerebrally injected to produce the haematoma. A catheter was introduced and chronically implanted in the contralateral ventricle for intracranial pressure monitoring. The animals were divided in two groups of 26 dogs each, according to haematoma location in subcortical or basal ganglia structures. The natural history was studied in both groups. Different types of treatment consisting in surgery, stereotactic evacuation, urokinase injection within the clot and both latter techniques combined were carried out 24 or 72 hours following haematoma production. Clinical status, systemic arterial pressure, intracranial pressure and CT scanning were used for result evaluation. Brain specimens were submitted for pathological examination. Our results indicate that stereotactic evacuation performed during the first 24 hours after haematoma occurrence was the most effective and innocuous procedure for basal ganglia lesions. Local urokinase plus stereotactic aspiration showed a high efficacy in controlling delayed basal ganglia and subcortical blood collections. Other therapeutic approaches behaved almost as the natural history.