Marc Raucoules-Aimé

An evaluation of the brachial plexus block at the humeral canal using a neurostimulator (1417 patients): the efficacy, safety, and predictive criteria of failure.

To evaluate the efficacy and safety of the multiple peripheral nerve block technique at the humeral canal (humeral block) with the use of a neurostimulator, we prospectively studied 1417 patients undergoing upper limb surgery with a brachial plexus block at the humeral canal (1468 blocks). The success rate (defined as sensory block [in all nerve distributions] and/or the absence of another anesthetic technique required to allow surgery) was 95%. The threshold of minimal stimulation used to locate each nerve before injecting the anesthetic solution was the unique predictive factor for identified failure. For the median nerve, the threshold was 0.8 mA with a relative risk of failure (RRf: relative risk evaluated by series of Taylor with a 95% confidence interval) = 1.49 (P = 0.04), for the radial nerve the threshold was 0.6 mA (RRf 1.3, P = 0.02), and 0.7 mA for the ulnar nerve (RRf 1.36, P = 0.04). For any equal or higher stimulation level, the risk of failure of the humeral block increased. For the musculocutaneous nerve, we did not observe a significant stimulation threshold for the risk of failure; although beyond 0.7 mA, the RRf was always more than 1.3. Adverse events occurred in 7% of all cases and were usually minor (nausea/vomiting, anxiety, local pain). Our study provides supplementary information on the efficacy and safety of this technique. Stimulation thresholds are clinically identified for the first time as the main factor linked to the failure of a technique using a neurostimulator. We conclude that the humeral block is a reliable peripheral block allowing good success rates results with minor complications, which can be used as an alternative to the axillary block. Implications We prospectively evaluated the feasability and the factors causing failure of a peripheral nerve block technique (humeral block) using neurostimulation in a large number of patients. The importance of the level of stimulation for the success of the block was evaluated for the first time.

Performance of Target-controlled Sufentanil Infusion in Obese Patients

Background Because obesity might affect pharmacokinetic parameters, the authors evaluated the accuracy of target-controlled sufentanil infusion in morbidly obese patients using a pharmacokinetic model usually applied to a normal-weight population. Methods Target-controlled propofol and sufentanil coinfusions were administered to 11 morbidly obese patients (body mass index: 45.0 ± 6.5 kg/m2) undergoing laparoscopic gastroplasty. The target plasma propofol concentration was 3 &mgr;g/ml. The effect-site sufentanil target concentration was initially 0.4 ng/ml but was modified during surgery as a function of blood pressure and heart rate. Plasma sufentanil concentrations were measured from the onset of infusion until 24 h after its termination. The predicted sufentanil target concentrations were calculated by STANPUMP software. Intrasubject data analyzed included calculation of performance error, median performance error, median absolute performance error, divergence, and wobble. Pharmacokinetic analysis was performed using a nonlinear mixed effect model. Results Applied sufentanil target concentrations ranged from 0.3 to 0.65 ng/ml. The mean ± SD plasma sufentanil concentration measured during spontaneous ventilation was 0.13 ± 0.03 ng/ml. Median performance error (range) was −13% (−42 to 36%). Median absolute performance error was 26% (8–44%) during infusion and 17% (12–59%) for the 24 h after its completion. The pharmacokinetic sets used slightly overpredicted the concentrations, with a median divergence of −3.4% (−10.2 to 3.1%) during infusion. For body mass index greater than 40, the overestimation of plasma sufentanil concentrations was greater. A two-compartment model with proportional error for interindividual variability best fitted the data. The residual variability was modeled as an additive (0.016 ng/ml) or proportional error (23%). Clearance, central volume of distribution, intercompartmental clearance, and peripheral volume of distribution (coefficient of variation) were 1.27 l/min (23%), 37.1 l (20%), 0.87 l/min (44%), and 92.7 l (22%), respectively. Conclusion The pharmacokinetic parameter set derived from a normal-weight population accurately predicted plasma sufentanil concentrations in morbidly obese patients.

The treatment of severe pulmonary edema induced by beta adrenergic agonist tocolytic therapy with continuous positive airway pressure delivered by face mask.

IMPLICATIONS We report the case of a pregnant patient who developed severe pulmonary edema secondary to beta-adrenergic agonist tocolytic therapy (salbutamol) and was successfully treated with mask-delivered continuous positive airway pressure ventilation.

Effects of Intrathecal Midazolam on Postoperative Analgesia When Added to a Bupivacaine-Clonidine Mixture

Background: Previous clinical and experimental studies have shown that a midazolam-clonidine mixture has a synergistic antinociceptive effect. This study evaluated the postoperative analgesic effect of adding midazolam to an intrathecal bupivacaine-clonidine mixture. Methods: One hundred ten patients scheduled to undergo elective lower-extremity surgery were enrolled in this double-blind, randomized trial. Spinal anesthesia was administered by using 1 of 2 mixtures. Group B-C received 12.5 mg isobaric 0.5% bupivacaine, 30 μg clonidine, and 0.4 mL 0.9% saline. Group B-C-M received the B-C mixture plus 2 mg of midazolam in a 0.4-mL solution. Motor and sensory block levels were assessed before, during, and after the procedure until regression of the block to S2. Sedation levels were determined before anesthesia, during surgery, and at the end of the procedure. Postoperative analgesia was assessed every 15 minutes by using a visual analog scale. Duration of sensory and motor blocks was determined based on a modified Bromage scale, and time of the first pain relief request was noted. Results: Duration of sensory block, time of first postoperative analgesic request, and amount of postoperative morphine administered were comparable between groups. However, the motor blockade lasted significantly longer in the B-C-M group compared with the B-C group (287 ± 73 minutes vs 257 ± 72 minutes, respectively; P < .05). Conclusion: Addition of midazolam to an intrathecal B-C mixture does not potentiate postoperative analgesia but prolongs the motor blockade.

High potential for epidural analgesia neuraxial block-associated hypotension in conjunction with heated intraoperative intraperitoneal chemotherapy.

ments, in these databases.3,4 Availability of long-term outcomes (e.g., incidence of chronic pain) and postdischarge complications5 would also be useful in assessing the overall effectiveness of postoperative epidural analgesia. Drs. Srinivasa, Kallmeyer, and Al-Tabbaa also note an understudied aspect of postoperative epidural analgesia: cost-effectiveness. Although the use of postoperative epidural analgesia may be associated with a higher “upfront” cost in terms of personnel and equipment, this modality may be shown to be “cost-effective” if future studies and analyses demonstrate that postoperative epidural analgesia decreases mortality and major morbidity and improves patient satisfaction, quality of life, and recovery.

Prise en charge anesthésique du patient diabétique

The prevalence of diabetes is rising and diabetics may soon represent more than 5% of the world population. The type 2 diabetes is a major independent risk factor for coronary artery disease. The screening for silent myocardial ischemia (IMS) must be systematic. The autonomic dysfunction and the cardiac microcirculatory disorders are at risk of hypotension and hypothermia during anesthesia. After 10 years of diabetes duration the incidence of perioperative complications and of difficult intubation are increased. The neurological deficits related to anesthesia are associated with general anesthesia in 85% of cases. Particular care will be provided during the surgical procedure to avoid skin, muscular and neurologic cuts. In most cases, the regional anesthesia will be preferred to general anesthesia. To avoid hypoglycemia, blood glucose concentration less than 11 mmol.L(-1)(2g.L(-1)) seems a reasonable target during and after surgery.

Prostate anaesthetic block with ropivacaine for urologic surgery.

Background and objective: The aim of this study was to evaluate prostate anaesthetic block for haemodynamic tolerance and quality of analgesia during and after transurethral surgery. Methods: Ninety adult males, ASA III/IV, were randomly assigned to receive a prostate anaesthetic block (n = 45) or spinal anaesthesia (n = 45). The main outcome measurement during anaesthesia, surgery and recovery was haemodynamic tolerance (number of hypotensive episodes, heart rate, systolic and mean blood pressures). Other outcome variables were pain scores during anaesthesia, surgery and every 4 h until 24 h after the end of surgery and amount of oral morphine required during the 24‐h postoperative period. Results: Sixty‐six patients were ASA III and 24 ASA IV. Ongoing cardiovascular therapies were comparable between groups. All surgical procedures were performed under good conditions. For patients receiving prostate anaesthetic block, the blood pressure and heart rate did not change significantly during the study period. For patients receiving spinal anaesthesia, the hypotension rate was 55.6% (n = 25) compared to 0 in the prostate anaesthetic block group (P < 0.001); 25 and 4 patients, respectively, required vascular filling and additional ephedrine administration. In both groups, all pain scores were <40 (100 mm visual analogue scale) during the study period. Oral morphine was given during the postoperative period to two prostate anaesthetic block patients and four who had received spinal anaesthesia (not significant). Conclusion: Transurethral surgery under prostate anaesthetic block is safe and assures adequate analgesia during and after surgery.

Évaluation de 44 filtres échangeurs de chaleur et d’humidité. Que choisir ?

Resume Objectif . – Si l’utilisation d’un filtre bacterien et viral en anesthesie est recommandee par la Societe francaise d’anesthesie et de reanimation ( Recommandations concernant l’hygiene en anesthesie, 1997), les criteres de choix ne sont pas clairement definis. De nombreux filtres echangeurs de chaleur et d’humidite (FECH), ayant des caracteristiques techniques differentes, sont proposes par l’industrie pharmaceutique. Type d’etude . – Le but de ce travail etait d’evaluer les differents FECH en utilisant les items ( n = 12) proposes par l’ American Association of Respiratory Care (AARC) et les dossiers techniques fournis par les laboratoires. Methodes . – Toutes les societes commercialisant des filtres ont ete contactees afin qu’elles fournissent leur dossier technique. Quarante-quatre filtres ont ete analyses (13 FECH mecaniques, 31 FECH electrostatiques). Chaque item a ete cote 0, 5 ou 10 (AARC) selon que le critere n’etait pas, etait partiellement ou totalement present. La note finale a ete ramenee a 10. Resultats . – Dix-sept filtres avaient une note superieure a 5. Il s’agissait de 8 filtres mecaniques et de 9 filtres electrostatiques. Les differences portaient essentiellement sur la taille des particules filtrees et sur la duree des tests. Certains filtres n’etaient pas valides par des organismes ou des laboratoires independants ( n = 28). Il existait des distorsions notables entre les documentations commerciales ou sur Internet, et les dossiers techniques ( n = 12). La suppression du critere de restitution d’humidite, qui peut etre considere par certains comme plus oriente sur la reanimation, ne changeait pas le classement des FECH. Discussion . – Il faut noter la bonne qualite des filtres proposes sur le marche, en particulier vis-a-vis des criteres recommandes par la Sfar que sont la nature du materiau filtrant, les valeurs d’efficacite de retention (ER = 99,9999 %), la reduction du titre et la duree du test. Les filtres electrostatiques utilises depuis peu en anesthesie possedent maintenant des taux de retention virale tres performants. Conclusion . – L’apparition de nouvelles normes ou protocoles de validation, le nombre de plus en plus important d’etudes publiees imposent de redefinir periodiquement les criteres de choix des FECH. Les controles de fabrication, la correspondance aux normes, les certificats de validation, les qualites ergonomiques, et l’adequation a nos besoins sont les elements principaux du choix d’un FECH.

Bacterial colonization of central venous catheters after heart valve surgery: a risk factor study

In the presence of a prosthetic heart valve, the colonization of a central venous catheter (CVC) has been implicated as a risk factor for endocarditis. Avoiding bacterial colonization of Central Venous Catheters (CVCs) is an everyday challenge for clinicians

Alcalose métabolique sévère et buveur de bière

Resume Le syndrome du buveur de biere associe classiquement une ingestion chronique excessive de biere a une hyponatremie profonde. Nous decrivons un cas clinique pour lequel l’alcalose metabolique est predominante alors que le trouble hydro-electrolytique n’est que modere. Nous emettons l’hypothese que l’osmolarite de la biere ingeree, associee au statut nutritionnel, puisse determiner la nature des troubles metaboliques et/ou hydro-electrolytiques rencontres.