François Girard

Neurostimulation in ultrasound-guided infraclavicular block: a prospective randomized trial.

Ultrasound guidance (USG) for infraclavicular blocks provides real time visualization of the advancing needle and local anesthetic distribution. Whether visualization of local anesthetic spread can supplant neurostimulation as the end point for local anesthetic injection during USG block has never been formally evaluated. Therefore, for this prospective randomized study, we recruited 72 patients scheduled for hand or forearm surgery and compared the speed of execution and quality of USG infraclavicular block with either USG alone (Group U) or USG combined with neurostimulation (Group S). In Group U, local anesthetic was deposited in a U-shaped distribution posterior and to each side of the axillary artery using as few injections as possible (1, 2, and 3 injections in 29, 6, and 3 patients, respectively). In Group S, a single injection was made after obtaining a distal motor response with a stimulating current between 0.3 and 0.6 mA. The anesthetic solution consisted of 0.5 mL/kg of lidocaine 1.5%, bupivacaine 0.125%, and epinephrine 1:200 000 (final concentrations). Procedure times were significantly shorter in Group U compared with Group S (3.1 ± 1.6 min and 5.2 ± 4.7 min, respectively; P = 0.006). In Group S, anesthetic spread was mainly anterior to the axillary artery in 37% of patients and mainly posterior in 63% of patients. Thirty minutes after the injection, 86% of patients in Group U had complete sensory block in the musculocutaneous, median, radial, and ulnar nerve territories compared with 57% in Group S (P = 0.007). Patients blocked in Group U with a single injection had the same rate of complete block (86%) as those blocked with more than one injection (86%). Block supplementation rates were 8% in Group U versus 26% in Group S (P = 0.049). Block failure occurred in one patient in Group S because of an inability to obtain a distal stimulation after 20 min. We conclude that USG infraclavicular block is more rapidly performed and yields a higher success rate when visualization of local anesthetic spread is used as the end point for injection. Posterolateral spread of local anesthetic around the axillary artery predicts successful block, circumventing the need for direct nerve visualization.

Scalp nerve blocks decrease the severity of pain after craniotomy

Up to 80% of patients report moderate to severe pain after craniotomy. In this study, we assessed the efficacy of scalp block for decreasing postoperative pain in brain surgery. Thirty patients scheduled for supratentorial craniotomy were enrolled. They were randomly divided into two groups: Ropivacaine (scalp block with 20 mL of ropivacaine 0.75%) and Saline (scalp block with 20 mL of saline 0.9%). Anesthesia was standardized. The scalp block was performed after skin closure and before awakening. Postoperative pain was assessed at 4, 8, 12, 16, 20, 24, and 48 h by using a 10-cm visual analog scale. Analgesia was provided with sub- cutaneous codeine as requested by the patient. Average visual analog scale scores were higher in the Saline group as compared with Ropivacaine (3.7 ± 2.4 vs 2.0 ± 1.6;P = 0.036). The total dose of codeine did not differ, nor did the duration of time before the first dose of codeine was required in the Ropivacaine (571 ± 765 min) versus Saline (319 ± 409 min;P = 0.17) group. In conclusion, we found that postoperative scalp block decreases the severity of pain after craniotomy and that this effect is long lasting, possibly through a preemptive mechanism.

Incidences of Venous Air Embolism and Patent Foramen Ovale among Patients Undergoing Selective Peripheral Denervation in the Sitting Position

OBJECTIVEThe incidence and severity of venous air embolism (VAE), a potentially fatal complication, among patients undergoing selective peripheral denervation in the sitting position have never been clearly established. We designed this retrospective study to assess the incidence and severity of VAE, the incidence of paradoxical air embolism, and the occurrence of patent foramen ovale, as detected with transesophageal echocardiography, as well as the effects of its detection on patient treatment. METHODSAfter institutional review board approval, data were collected from the charts of all patients who underwent selective peripheral denervation at our institution between 1988 and 2001. The severity of VAE was assessed by using a 5-point scale. RESULTSData for 342 patients were available for analyses. Seven patients exhibited VAE, yielding an incidence of 2%. The severity of VAE was 2/5 for three patients, 3/5 for three patients, and 4/5 for one patient. Air could be aspirated from the central venous catheter for three patients. No deaths occurred. Among the 96 transesophageal echocardiographic examinations performed, 5 cases of patent foramen ovale were detected (5.2%). For those patients, surgery was performed in the prone or park-bench position. No paradoxical air embolism was detected. CONCLUSIONThis is the first large study to directly assess the incidence and severity of VAE among patients undergoing selective peripheral denervation in the sitting position. We recommend that the detection of a patent foramen ovale prompt a change in position for this surgical procedure.

Polypyrrole film electrodes electrochemically doped with tetrathiomolybdate anions : preparation and characterization

Polypyrrole films containing tetrathiomolybdate anions and molybdenum trisulfide have been prepared on platinum and tin oxide coated glass electrodes by anodic electrochemical deposition from an aqueous solution containing pyrrole and ammonium tetrathiomolybdate. The scanning electron micrographs of these films show a porous structure. Cyclic voltammetry at a tin oxide electrode in a solution containing pyrrole and tetrathiomolybdate suggests that the formation of the polymer proceeds initially by a nucleation process. The current-time transient for film deposition remains fairly constant for long elapsed times, after the initial decrease and rise, indicating the formation of a fairly conducting layer. A linear relationship is observed between both film thickness, the weight of molybdenum in the polypyrrole-tetrathiomolybdate film and the charge passed during film formation. The cyclic voltammogram of the polypyrrole-tetrathiomolybdate film is characterized by an apparent redox potential, taken as the average between the anodic and cathodic peaks, of approx. −0.3 V vs. SCE. The latter is shifted to a more negative potential in comparison with that of a polypyrrole-chloride film electrode. This negative shift is characteristic of polypyrrole film doped with some “immobile” dopant. In this case the redox processes involve insertion of cations from the supporting electrolyte during film reduction and expulsion during oxidation. This was confirmed by cyclic voltammetry which is strongly dependent on the size of the electrolyte cation and independent of the electrolyte anion. Elemental analysis shows that the polypyrrole-tetrathiomolybdate film contains 70% MoS3 and 30% MoS42− relative to the molybdenum content. The conductivity of a polypyrrole-tetrathiomolybdate film is at least two orders of magnitude larger than that of a molybdenum trisulfide film.

Gabapentin does not reduce post-thoracotomy shoulder pain: a randomized, double-blind placebo-controlled study.

Purpose: Despite adequate epidural analgesia, up to 97% of patients undergoing thoracotomy experience ipsilateral shoulder pain. In this setting, this study evaluated the safety and the efficacy of pre-emptive gabapentin.Methods: A double-blind, placebo-controlled study was undertaken in 51 patients randomized into two groups. Two hours before surgery, 23 patients received gabapentin 1200 mgpo (Group G), and 28 patients received placebo (Group P). Shoulder pain and postoperative pain, at the surgical site, were monitored every four hours for 24 hr, using a numerical rating scale. Subcutaneous hydromorphone was administered for rescue analgesia against shoulder pain.Results: Forty-four patients complained of shoulder pain (prevalence of 86%). Demographic and surgical data were similar between the two groups. There were no significant differences in the total cumulative doses of hydromorphone administered at eight, 16, and 24 hr, nor were there differences in individual numerical rating scale scores for shoulder pain. The groups were similar with respect to the degree of pain at the surgical site. The frequency of side effects between groups at corresponding time intervals was also similar, with the exception of sedation. At four hours, the incidence of sedation scores τ; 1 was greater in Group G (21/23 patients), compared to Group P (18/28 patients;P=0.025). In contrast, by 24 hr, 5/18 patients in Group P had sedation scores τ;1, compared to 0/28 patients in Group G (P=0.05).Conclusion: Pre-emptively administered gabapentin, 1200 mg, does not reduce the incidence, or the severity, of post-thoracotomy shoulder pain in patients receiving thoracic epidural analgesia.RésuméObjectif: Malgré une analgésie péridurale adaptée, jusqu’à 97. % des patients subissant une thoracotomie éprouvent de la douleur à l’épaule ipsilatérale. Dans ce contexte, notre étude a évalué l’innocuité et l’efficacité de la gabapentine administrée de façon préventive.Méthode: Une étude à double insu et contrôlée par placebo a été menée ; elle évaluait 51 patients randomisés en deux groupes. Deux heures avant la chirurgie, 23 patients ont reçu de la gabapentine 1200 mg oralement (groupe G) et 28 un placebo (groupe P). La douleur à l’épaule et la douleur postopératoire au site chirurgical ont été évaluées toutes les quatre heures durant 24 h à l’aide d’une échelle d’évaluation numérique. De l’hydromorphone souscutanée a été administrée en analgésie de secours contre la douleur à l’épaule.Résultats: Quarante-quatre patients se sont plaints de douleur à l’épaule (prévalence de 86 %). Les données démographiques et chirurgicales étaient semblables dans les deux groupes. Il n’y a pas eu de différence significative dans les doses cumulatives totales d’hydromorphone administrée à huit, seize et 24 h, ni dans les scores individuels sur l’échelle d’évaluation numérique pour la douleur à l’épaule. Les groupes ont présenté des résultats semblables concernant le degré de douleur au site chirurgical. La fréquence des effets secondaires, comparée entre les groupes à des intervalles correspondants, était également similaire, à l’exception de la sédation. À quatre heures, l’incidence de scores de sédation τ;1 était plus élevée dans le groupe G (21/23 patients), comparé au groupe P (18/28 patients; P=0,025). En revanche, à 24 heures, 5/18 patients du groupe P présentaient des scores de sédation τ;1, comparé à 0/28 patients dans le groupe G (P=0,05).Conclusion: La gabapentine 1200 mg administrée de façon préventive ne réduit pas l’incidence ou la sévérité de la douleur à l’épaule post-thoracotomie chez les patients recevant une analgésie péridurale thoracique.

Craniotomy site influences postoperative pain following neurosurgical procedures: a retrospective study

ObjectiveThis retrospective study was designed to assess the intensity of postoperative pain in relation to the location of craniotomy.MethodsAfter Research Ethics Board approval, data were collected from the charts of all patients who underwent a craniotomy at our institution between January 2004 and December 2005. The severity of post-craniotomy pain was assessed by collecting scores obtained using an 11-point verbal rating scale and calculating the cumulative analgesic requirements for the first 48 hr postoperatively. Data were compared according to the craniotomy location.ResultsData from 299 patients was available for analysis. On average, 76% of patients experienced moderate to severe postoperative pain. Frontal craniotomy was associated with lower pain scores than four of six craniotomy sites analyzed, with 49% of patients reporting mild pain, a significant difference (P < 0.05) compared with all other groups except for parietal craniotomies. Frontal craniotomy patients also had lower opioid analgesic requirements compared to patients who underwent posterior fossa craniotomy (P < 0.05). Logistic regression analysis showed that craniotomy location (P < 0.0001 ) and age (P = 0.004) were both independent predictors of the intensity of postoperative pain, with lower pain scores as age increased. Postoperative use of steroids, gender and presence of preoperative pain were not statistically linked to postoperative pain intensity. The prevalence of postoperative nausea and vomiting was 56% and it did not vary according to the location of craniotomy.ConclusionThis study shows that the intensity of postoperative pain in neurosurgery is affected by the site of craniotomy. Frontal craniotomy patients experienced the lowest pain scores, and required significantly less opioid than patients undergoing posterior fossa interventions.ObjectifCette étude rétrospective a été conçue pour évaluer l’intensité de la douleur postopératoire par rapport au site de craniotomie.MéthodeAvec l’accord du Comité d’éthique de la recherche, les données des dossiers de tous les patients ayant subi une craniotomie dans notre institution entre janvier 2004 et décembre 2005 ont été compilées. La sévérité de la douleur suite à la craniotomie a été évaluée en récoltant les scores obtenus à l’aide d’une échelle d’évaluation verbale de 11 points et en calculant les besoins analgésiques cumulatifs pour les 48 heures suivant l’opération. Les données ont été comparées selon l’emplacement de la craniotomie.RésultatsLes données de 299 patients étaient disponibles pour analyse. En moyenne, 76 % des patients ont ressenti des douleurs postopératoires modérées à sévères. La craniotomie frontale était associée à des scores de douleur plus bas que quatre des six sites de craniotomie évalués, avec 49 % des patients signalant une douleur légère, une différence significative (P < 0,05) comparée à tous les autres groupes hormis les craniotomies pariétales. Les patients ayant subi une craniotomie frontale présentaient également des besoins plus faibles en analgésiques opiacés par rapport aux patients ayant subi des craniotomies de la fosse postérieure (P < 0,05). Une analyse par régression logistique a montré que l’emplacement de la craniotomie (P < 0,001) ainsi que l’âge (P = 0,004) constituent tous deux des prédicteurs indépendants de l’intensité de la douleur postopératoire, les scores de douleur étant plus bas chez les patients plus âgés. L’utilisation postopératoire de stéroïdes, le sexe et la présence de douleur préopératoire n’étaient pas statistiquement associés à l’intensité de la douleur postopératoire. La prévalence de nausées et de vomissements postopératoires était de 56 % et n’était pas affectée par le site de la craniotomie.ConclusionCette étude démontre que l’intensité de la douleur postopératoire en neurochirurgie est affectée par le site de craniotomie. Les patients ayant subi une craniotomie frontale ont obtenu les scores de douleur les plus bas, et leurs besoins en opiacés ont été significativement moindres que chez les patients ayant subi des interventions sur la fosse postérieure.

Bilateral sixth cranial nerve palsy after unintentional dural puncture

PurposeBilateral sixth nerve palsy is a known though uncommon complication following dural puncture. The recommended treatment consists of hydration and alternate monocular occlusion. The value and the timing of an epidural blood patch (EBP) for sixth nerve palsy remains controversial as some authors have demonstrated benefits in performing an EBP early in course of the nerve palsy whereas others have not found any advantage when an EBP was performed later.Clinical featuresA 40-yr-old woman developed bilateral sixth nerve palsy ten days after an unintentional dural puncture. An EBP was done within 24 hr after the onset of the symptoms and immediate improvement of the diplopia was noted by the patient and confirmed by an ophthalmologist. Complete resolution of the diplopia occurred 36 days after the dural puncture.ConclusionBlood patching within 24 hr of the onset of diplopia may be a reasonable treatment for ocular nerve palsy as it relieved the postdural puncture headache and produced partial improvement of the diplopia.RésuméObjectifLa paralysie bilatérale du sixième nerf crânien (abducens) est une complication connue, mais rare, de la ponction durale. Le traitement recommandé consiste en l’hydratation et l’occlusion monoculaire alternée. La valeur d’un colmatage sanguin péridural (CSP), en cas de paralysie du nerf abducens, et le moment choisi pour le réaliser, demeurent controversés, car certains auteurs ont démontré les avantages d’un CSP précoce au cours de la paralysie alors que d’autres n’ont trouvé aucun avantage à un CSP plus tardif.Éléments cliniquesUne paralysie bilatérale du nerf abducens s’est développée chez une femme de 40 ans, dix jours après une brèche durale accidentelle. Un CSP a été fait dans les 24 h suivant l’apparition des symptômes et une amélioration immédiate de la diplopie a été constatée par la patiente et confirmée par un ophtalmologiste. La résolution complète de la diplopie est survenue 36 jours après la ponction durale.ConclusionLe colmatage sanguin péridural réalisé dans les 24 h qui suivent l’apparition d’une diplopie constitue un traitement raisonnable de la paralysie du nerf abducens, puisqu’il soulage la céphalée post-ponction durale et réduit partiellement la diplopie.

Postoperative anemia does not impede functional outcome and quality of life early after hip and knee arthroplasties

BACKGROUND: Clinicians have adopted a restrictive transfusion threshold (75‐80 g/L) after major orthopedic surgery. Anemia may be associated with a decrease in postoperative vigor. We hypothesize that, in these patients, a threshold hemoglobin (Hb) concentration exists below which functional recovery and quality of life (QoL) become difficult.

Tracheal Intubation Through the I-gelTM Supraglottic Airway Versus the LMA FastrachTM: A Randomized Controlled Trial

BACKGROUND The i-gel™ is a supraglottic airway device not requiring inflation of a cuff for lung ventilation. Its design allows for unobstructed passage of a tracheal tube and previous studies have demonstrated a favorable alignment with the glottic inlet. In this prospective randomized study, we compared the success rate of blind tracheal intubation using the i-gel and the laryngeal mask airway (LMA) Fastrach™. METHODS One hundred sixty patients requiring general anesthesia and airway management were randomized to tracheal intubation using the i-gel or the LMA Fastrach. After induction of general anesthesia, the allocated device was inserted and adequate lung ventilation was confirmed. Blind tracheal intubation was then attempted. First attempt and overall tracheal intubation success rates were evaluated and tracheal intubation times were measured. RESULTS Eighty patients were recruited in each study group. Successful tracheal intubation was obtained on the first attempt in 69% of patients with the i-gel and 74% of patients with the LMA Fastrach (95% confidence interval [CI] of difference, -9% to 19%, P = 0.60). The overall intubation success rate was lower using the i-gel than it was using the LMA Fastrach (73% vs 91%, 95% CI of difference, 7% to 31%, P < 0.0001). CONCLUSIONS On first attempts, successful blind tracheal intubation was obtained at comparable rates using the i-gel and the LMA Fastrach. However, when the first attempt was unsuccessful, subsequent attempts through the i-gel did not significantly increase tracheal intubation success rate. The LMA Fastrach yielded a higher overall intubation success rate.

Sevoflurane provides faster recovery and postoperative neurological assessment than isoflurane in long-duration neurosurgical cases.

Sevoflurane (SEVO) provides faster emergence than isoflurane (ISO). This advantage is thought to magnify with increased duration of exposure. In addition, SEVO has several of the characteristics of an ideal neuroanesthetic. We designed a prospective, randomized, double-blinded study to compare the recovery profile of SEVO versus ISO in neurosurgery. Sixty patients undergoing intracranial surgery were enrolled. They were randomized to receive SEVO or ISO in 40% oxygen as part of a balanced anesthetic regimen. The anesthetic concentration (0.5 to 1.0 minimum alveolar anesthetic concentration [MAC]) was adjusted to maintain mean arterial blood pressure within 20% of the preinduction baseline. At the end of the surgery, neuromuscular blockade was reversed, anesthetics were discontinued without prior tapering, and fresh gas flow was increased to 10 L/min. Recovery end-points were measured as the time from closure of the anesthetic vaporizer. Mean MAC-hours were identical in both groups (4.7). Patients in the SEVO group demonstrated a shorter time to emergence (P = 0.02) and for response to command (squeeze hand, P = 0.03; move feet, P = 0.01). Patients in the SEVO group obtained a Glasgow coma scale score of ≥10 5 min before patients in the ISO group (P = 0.04). Obtaining an early neurological examination can be critical in neurosurgical patients. The observed difference in emergence between SEVO and ISO could therefore be of clinical importance.