Philippe Chouinard

Ultrasound guidance speeds execution and improves the quality of supraclavicular block.

In this prospective study, we assessed the quality, safety, and execution time of supraclavicular block of the brachial plexus using ultrasonic guidance and neurostimulation compared with a supraclavicular technique that used anatomical landmarks and neurostimulation. It was hypothesized that ultrasonic guidance would increase the proportion of successful blocks, decrease block execution time, and reduce the incidence of complications such as pneumothorax and neuropathy. Eighty patients were randomized into two groups of 40, Group US (supraclavicular block guided in real time by a two-dimensional ultrasonic image, with neurostimulator confirmation of correct needle position) and Group NS (supraclavicular block using the subclavian perivascular approach, also with neurostimulator confirmation). Blocks were performed using bupivacaine 0.5% and lidocaine 2% (1:1 vol) with epinephrine 1:200,000 as the anesthetic mixture. The onset of motor and sensory block for the musculocutaneous, median, radial, and ulnar nerves was evaluated over a 30 min period. At 30 min 95% of patients in Group US and 85% of patients in Group NS had a partial or complete sensory block of all nerve territories (P = 0.13) and 55% of patients in Group US and 65% of patients in Group NS had a complete block of all nerve territories (P = 0.25). Surgical anesthesia without supplementation was achieved in 85% of patients in Group US and 78% of patients in Group NS (P = 0.28). No patient in Group US and 8% of patients in Group NS required general anesthesia (P = 0.12). The quality of ulnar block was significantly inferior to the quality of block in other nerve territories in Group NS, but not in Group US; the quality of ulnar block was not significantly different between Groups NS and US. The block was performed in an average of 9.8 min in Group NS and 5.0 min in Group US (P = 0.0001). No major complication occurred in either group. We conclude that ultrasound-guided neurostimulator-confirmed supraclavicular block is more rapidly performed and provides a more complete block than supraclavicular block using anatomic landmarks and neurostimulator confirmation.

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.

Ultrasound-guided infraclavicular versus supraclavicular block.

In this prospective study we compared ultrasound-guided (USG) infraclavicular and supraclavicular blocks for performance time and quality of block. We hypothesized that the infraclavicular approach would result in shorter performance times with a quality of block similar to that of the supraclavicular approach. Eighty patients were randomized into two equal groups: Group I (infraclavicular) and Group S (supraclavicular). All blocks were performed using ultrasound visualization with a 7.5-MHz linear probe and neurostimulation. The anesthetic mixture consisted of 0.5 mL/kg of bupivacaine 0.5% and lidocaine hydrocarbonate 2% (1:3 vol.) with epinephrine 1:200,000. Sensory block, motor block, and supplementation rates were evaluated for the musculocutaneous, median, radial, and ulnar nerves. Surgical anesthesia without supplementation was achieved in 80% of patients in group I compared with 87% in Group S (P = 0.39). Supplementation rates were significantly different only for the radial territory: 18% in Group I versus 0% in group S (P = 0.006). Block performance times were not different between groups (4.0 min in Group I versus 4.65 min in Group S; P = 0.43). Technique-related pain scores were not different between groups (I: 2.0; S: 2.0; P = 1.00). We conclude that USG infraclavicular block is at least as rapidly executed as USG supraclavicular block and produces a similar degree of surgical anesthesia without supplementation.

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.

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.

A Comparison Between Scalp Nerve Block and Morphine for Transitional Analgesia After Remifentanil-Based Anesthesia in Neurosurgery

We compared transitional analgesia provided by scalp nerve block (SNB) or morphine after remifentanil-based anesthesia in neurosurgery. Fifty craniotomy patients were randomly divided into two groups: morphine (morphine 0.1 mg · kg−1 IV after dural closure and an SNB performed with 20 mL of 0.9% saline at the end of surgery) and block (10 mL of 0.9% saline instead of morphine after dural closure and an SNB performed with a 1:1 mixture of bupivacaine 0.5% and lidocaine 2% at the end of surgery). Postoperative pain was assessed at 1, 2, 4, 8, 12, 16, and 24 h using a 10-point numerical rating scale. Analgesia consisted of subcutaneous codeine. Average numerical rating scale scores were similar between the two groups at each time interval. Total codeine dosage was also similar, except at 4 h postoperatively when it was higher in the block group. The delay before administration of the first dose of codeine was not statistically different between groups: 45 min (20–2880) vs 30 min (10–2880), median and range for the block and morphine group, respectively. Postoperative hemodynamics were similar for both groups. The incidence of nausea and vomiting was slightly more frequent in the morphine group, but the occurrence of confusion did not differ between groups. In conclusion, SNB provides a quality of transitional analgesia that is similar to that of morphine with the same postoperative hemodynamic profile.

Cisatracurium-Induced Neuromuscular Blockade Is Affected by Chronic Phenytoin or Carbamazepine Treatment in Neurosurgical Patients

The effect of chronic anticonvulsant therapy (CAT) on the maintenance and recovery profiles of cisatracurium-induced neuromuscular blockade has not been adequately studied. In this study, we compared the pharmacokinetics and pharmacodynamics of cisatracurium after a prolonged infusion in patients with or without CAT. Thirty patients undergoing intracranial surgery were enrolled in the study: 15 patients under CAT (carbamazepine and phenytoin, Group A) and 15 controls receiving no anticonvulsant therapy (Group C). Anesthesia was standardized and both groups received a bolus of cisatracurium followed by an infusion to maintain a 95% twitch depression. A steady-state was obtained and the infusion was kept constant for 2 additional hours. Neuromuscular blockade was then allowed to spontaneously recover. Blood samples were taken for measurement of cisatracurium plasma concentration during the steady-state period (Cpss95) and at various times during recovery. Demographic and intraoperative data were similar. CAT resulted in faster 25% and 75% recovery of the first twitch. The rate of infusion of cisatracurium needed to maintain a 95% twitch depression at steady-state was 44% faster in Group A (P < 0.001). The clearance of cisatracurium was significantly faster in Group A when compared with Group C (7.12 ± 1.87 versus 5.72 ± 0.70 L · kg−1 · min−1, P = 0.01). The Cpss95 was also significantly larger in Group A (191 ± 45 versus 159 ± 36 ng/mL, P = 0.04). In addition, patients receiving CAT had a 20% increase in the clearance of cisatracurium that, in turn, resulted in a faster recovery of neuromuscular blockade after an infusion of the drug. Also, patients under CAT had a 20% increase in their Cpss95, indicating an increased resistance to the effect of cisatracurium.

Esophageal doppler and thermodilution are not interchangeable for determination of cardiac output

PurposeThis study compares thermodilution cardiac output (TD-CO) and esophageal Doppler cardiac output (ED-CO) during periods of hemodynamic stability and after heart stabilization during off-pump coronary artery bypass (OPCAB) surgery.MethodsAfter Institutional Review Board approval, 58 patients undergoing OPCAB had simultaneous comparison of TDCO and ED-CO at three time periods. Measurements were recorded, in a blinded manner, after probe insertion (T0), immediately before and after (T1,T2) heart displacement and before starting any pharmacological treatment (if needed) to maintain systolic blood pressure to its value before heart mobilization. Measurements were also taken before sternal closure (Tfinal).ResultsThree hundred and two pairs of data were analyzed using the Bland and Altman method. Bias, standard deviation (SD) of the bias (precision), and degree of agreement (bias ± 2 SD) were calculated. Based on published literature, we considered that the highest degree of agreement should be < 0.5 L·min-1 to consider both methods as interchangeable. At T0, bias and SD of bias between TD-CO and ED-CO were -0.1 ± 1.0 L·min-1. Immediately before heart stabilization, bias ± SD was 0.6 ± 1.0 L·min-1 and after heart displacement, 0.5 ± 0.8 L·min-1. At Tfinal, bias ± SD was 0.7± 0.7 L·min-1.ConclusionBecause the degree of agreement was < 0.5 L·min-1 at all measurement periods except T0, we conclude that TD and ED are not interchangeable at any time during OPCAB surgery.RésuméObjectifComparer le débit cardiaque obtenu par thermodilution (DC-TD) à celui du Doppler œsophagien (DC-DO) pendant la stabilité hémodynamique et après la stabilisation cardiaque au cours ďun pontage aortocoronarien à cœur battant (PACCB).MéthodeAvec ľapprobation du Comité de révision, nous avons recruté 58 patients devant subir un PACCB pour une comparaison simultanée du DC-TD et DC-DO à trois moments différents. Les mesures ont été enregistrées à ľaveugle, après ľinsertion de la sonde (T0), immédiatement avant et après (T1,T2) le déplacement du cœur et avant de commencer tout traitement pharmacologique, si nécessaire, pour maintenir la tension artérielle systolique à ses valeurs ďavant la mobilisation cardiaque. Des mesures ont aussi été prises avant la fermeture sternale (Tfinal).RésultatsTrois cent deux paires de données ont été analysées selon la méthode de Bland et Altman. Le biais, ľécart type (ET) du biais (précision) et le degré de concordance (biais ± 2 ET) ont été calculés. Sur la base des publications consultées, le degré le plus élevé de concordance devrait être < 0,5 L·min-1 pour conclure que les deux méthodes sont interchangeables. Au T0, le biais et ľET du biais entre DC-TD et DC-DO ont été de -0,1 ± 1,0 L·min-1. Immédiatement avant la stabilisation du cœur, le biais ± ET était de 0,6 ± 1,0 L·min-1 et après le déplacement du cœur, de 0,5 ± 0,8 L·min-1. Au Tfinal, le biais ± ET était de 0,7 ± 0,7 L·min-1.ConclusionLe degré de concordance étant < 0,5 L·min-1 pour toutes les mesures, sauf au T0, nous concluons que la TD et le DO ne sont pas interchangeables pendant le PACCB.Purpose: This study compares thermodilution cardiac output (TD-CO) and esophageal Doppler cardiac output (ED-CO) during periods of hemodynamic stability and after heart stabilization during off-pump coronary artery bypass (OPCAB) surgery. Methods: After Institutional Review Board approval, 58 patients undergoing OPCAB had simultaneous comparison of TDCO and ED-CO at three time periods. Measurements were recorded, in a blinded manner, after probe insertion (T0), immediately before and after (T1,T2) heart displacement and before starting any pharmacological treatment (if needed) to maintain systolic blood pressure to its value before heart mobilization. Measurements were also taken before sternal closure (Tfinal). Results: Three hundred and two pairs of data were analyzed using the Bland and Altman method. Bias, standard deviation (SD) of the bias (precision), and degree of agreement (bias ± 2 SD) were calculated. Based on published literature, we considered that the highest degree of agreement should be 0.5 L·min –1 at all measurement periods except T0, we conclude