Monitoring neuromuscular block: an update.

The first part of this article presents an update of the basic considerations of neuromuscular monitoring. It emphasises the need to assure supramaximal stimulation, to place the stimulating electrodes correctly and to use appropriate sites for nerve stimulation as well as appropriate stimulation patterns. The second part focuses on current developments and ongoing discussion. The authors describe the performance of acceleromyography and the need for initial calibration when using these quantitative devices.

Reversal of rocuronium-induced neuromuscular block with sugammadex is faster than reversal of cisatracurium-induced block with neostigmine.

BACKGROUND: Reversal of the residual effect of rocuronium or cisatracurium by neostigmine may be slow and associated with side-effects. This randomized, safety-assessor-blinded study compared the efficacy of sugammadex, a selective relaxant binding agent for reversal of rocuronium-induced neuromuscular block, with that of neostigmine for reversal of cisatracurium-induced neuromuscular block. The safety of sugammadex and neostigmine was also evaluated. METHODS: Adult surgical patients (ASA class I-III) were randomized to sugammadex 2.0 mg kg(-1) for reversal of block induced by rocuronium 0.6 mg kg(-1), or neostigmine 50 microg kg(-1) for reversal of block induced by cisatracurium 0.15 mg kg(-1). Anaesthesia was induced and maintained using i.v. propofol and remifentanil, fentanyl, or sufentanil. Neuromuscular function was monitored using acceleromyography (TOF-Watch SX). Sugammadex or neostigmine was administered at reappearance of T(2). The primary efficacy variable was time for recovery of the train-of-four (TOF) ratio to 0.9. RESULTS: Eighty-four patients were randomized, 73 of whom received sugammadex (n=34) or neostigmine (n=39). Time from start of administration of reversal agent to recovery of the TOF ratio to 0.9 was 4.7 times faster with sugammadex than with neostigmine (geometric mean=1.9 vs 9.0 min, P<0.0001). Reversal of block was sustained in all patients. There were no serious adverse effects from either reversal agent and no significant changes in any measure of safety, except for similar elevations in urinary N-acetyl glucosaminidase in both groups. CONCLUSIONS: Sugammadex 2.0 mg kg(-1) administered at reappearance of T(2) was significantly faster in reversing rocuronium-induced blockade than neostigmine was in reversing cisatracurium-induced block.

Relationship between procalcitonin values and infection in brain-dead organ donors.

BACKGROUND AND AIMS: An association between the inflammatory reactions estimated by several biomarkers and organ dysfunction has been reported in brain-dead organ donors (BDOD). Procalcitonin (PCT), a biomarker of inflammation due to bacterial infection, is increased among BDOD. However, is not known whether infection changes PCT values in BDOD. MATERIALS AND METHODS: We retrospectively analyzed 82 BDOD including several demographic and clinical parameters, bacterial culture results, antibiotics prescription, and plasma values of PCT measured before organ harvesting. Infection was diagnosed to be either a positive bacterial culture (restricted definition) and/or prescription of antibiotics (extended definition). RESULTS: The median PCT value was 1.5 (interquartile range [IQR], 0.4 to 6.9; range, 0 to 526 ng/mL; n=82). Thirty-eight (46%) and 24 (29%) patients had PCT values>2 ng/mL and >5 ng/mL, respectively. Median PCT values among infected (1.18; IQR, 0.27 to 6.55 ng/mL) versus noninfected (1.57; IQR, 0.53 to 7.15 ng/mL) BDOD (restricted definition) were not different (P=.36). The area under the receiver operating characteristic curve using PCT to predict infection (restricted definition) was 0.52. Specificity of PCT to predict infection was above 80% at PCT values>9 ng/mL. CONCLUSION: Our results confirmed PCT values are increased in BDOD, suggesting that this was not related to an infectious cause (whatever definition was used) unless PCT values are high.

[Renal angiomyolipoma rupture during pregnancy]. / Rupture d'un angiomyolipome rénal lors d'une grossesse.

A 40 year-old 2nd gesta pregnant woman (34.5 weeks of amenorhea) was admitted to hospital for abdominal pain and arterial hypotension which were rapidly related to a retroperitoneal haematoma due to left kidney bleeding. Emergency cesarean delivery under general anaesthesia was undertaken because of foetal distress. Exploration of the retroperitonal space after foetal extraction confirmed the presence of a large haematoma and abnormal left renal morphology. The retroperitoneal space was drained without any further intervention. Subsequently, abdominal and thoracic computerised tomographic examination showed bilateral dysplasia of the kidneys and pulmonary cysts consistent with the diagnosis of renal angiomyolipoma and pulmonary lymphangioleiomyomatosis. The case report is of interest because of the circumstances of discovery of the disease and because nephrectomy was not necessary to control the bleeding of the left kidney. Six months after the incident the patient and the child are in good condition.

Telerobotic-assisted laparoscopic hysterectomy for benign and oncologic pathologies: initial clinical experience with 30 patients.

BACKGROUND: Telerobotic-assisted laparoscopic attempts to provide technological solutions to the inherent limitations of traditional laparoscopic surgery. The aim of this study is to report the first experience of two teams concerning telerobotic-assisted laparoscopic hysterectomy for benign and malignant pathologies. METHODS: This study included 14 patients at the University Hospital Saint Pierre of Brussels (Belgium) and 16 patients at the Cancer Center of Nancy (France) from September 1999 to July 2003. RESULTS: The indications for surgery were uterine malignant diseases in 12 cases (stade I) (41%), and benign pathologies of the uterus in 18 cases (59%). Five postoperative complications (17%) occurred, none related to the robotic system. CONCLUSION: Robotic surgery can be safely performed in gynecologic and gynecologic-oncologic surgery with no increase in complication rates. A significant advance is represented by the surgeon's ergonomic improvement.

[Influence of pregnancy on renal angiomyolipoma]. / Rôle de la grossesse dans la rupture d'un angiomyolipome rénal.

The aim is to perform a literature search on the role of pregnancy in the rupture of renal angiomyolipoma. Articles published from 1952 to 2004 in the Medline database were searched using the keywords renal angiomylipoma and pregnancy. Pathologies associated with angiomylipoma (lymphangioleiomyomatosis and Bourneville tuberous sclerosis) were taken into account. Seventy-two cases of association of renal angiomyolipoma and pregnancy were found, out of which 58 presented a haemorrhage. In only 26% of the cases, renal angiomyolipoma had been documented prior to pregnancy. Clinical presentation was similar to cases occurring among non pregnant women: abdominal pains (88%), hypotension or shock (33%) and hematuria (24%). Average size of the rupture was 11,7 cm. Rupture does not occur solely with the first pregnancy but occurred equally during the first, second and third pregnancy. Average gestation age upon occurrence of haemorrhage was 27 weeks with a minimum at ten weeks. Therapeutic strategies at the time of shock or hypotension were total nephrectomy in 79% of the cases, 7% polar nephrectomy, 7% embolisation followed by nephrectomy and 7% abstention. A causal role of pregnancy in the atraumatic rupture of angiomyolipoma is not clearly defined. Nevertheless, many arguments (whether it be abdominal mechanical pressure, hormonal or histological ones) suggest that a pregnancy could increase the risk of renal angiomyolipoma rupture. These patients should have a medical follow-up period at closer intervals during their pregnancy and the postpartum phase.

Example of cost calculations for an operating room and a post-anaesthesia care unit.

OBJECTIVE: The aim of this study was to evaluate the cost of an operating room using data from our hospital. Using an accounting-based method helped us. METHODS: Over the year 2012, the sum of direct and indirect expenses with cost sharing expenses allowed us to calculate the cost of the operating room (OR) and of the post-anaesthesia care unit (PACU). RESULTS: The cost of the OR and PACU was €10.8 per minute of time offered. Two thirds of the direct expenses were allocated to surgery and one third to anaesthesia. Indirect expenses were 25% of the direct expenses. The cost of medications and single use medical devises was €111.45 per anaesthesia. The total cost of anaesthesia (taking into account wages and indirect expenses) was €753.14 per anaesthesia as compared to the total cost of the anaesthesia. The part of medications and single use devices for anaesthesia was 14.8% of the total cost. CONCLUSION: Despite the difficulties facing cost evaluation, this model of calculation, assisted by the cost accounting controller, helped us to have a concrete financial vision. It also shows that a global reflexion is necessary during financial decision-making.

Pharmacokinetics and pharmacodynamics of rocuronium at the vocal cords and the adductor pollicis in humans.

The pharmacokinetic-pharmacodynamic relationship of rocuronium at the laryngeal adductor muscles and the adductor pollicis was determined in eight patients during general anesthesia. Rocuronium was administered as an infusion at a rate of 100 micrograms.kg-1.min-1 over 5 minutes. The half-life of transport between plasma and biophase (effect compartment) was significantly shorter at the adductor laryngeal muscles (2.7 +/- 0.6 minutes, mean +/- SD) than at the adductor pollicis (4.4 +/- 1.5 minutes, p = 0.003). The concentration in the effect compartment producing 50% of the maximum effect was significantly greater at the adductor laryngeal muscles (1424 +/- 148 micrograms.L-1) than at the adductor pollicis (823 +/- 157 micrograms.L-1, p = 0.0001). The shorter onset of neuromuscular blockade at the laryngeal muscles than at the adductor pollicis may be explained by a faster transfer rate at the laryngeal adductor muscles neuromuscular junction than at the adductor pollicis neuromuscular junction.

Evaluation of donor cardiac function for heart transplantation: experience of a French academic hospital.

OBJECTIVES: The diagnostic and therapeutic approaches for evaluation and management of cardiac function in brain-dead patients vary from country to country. The aim of the present study was to describe the results of the evaluation of brain-dead patients as potential cardiac donors in a French teaching hospital that manages the largest number of brain-dead patients in France. METHODS: Demographic parameters, the causes of brain death, clinical evolution, hemodynamic parameters, doses of inotropic and/or vasopressive drugs, the results of echocardiographic examination, and several biochemical markers of myocardial cell injury were retrospectively collected. RESULTS: Seventy-one consecutive brain-dead patients admitted to the intensive care unit of the Academic Hospital of Nancy from October 1st, 1998 to September 30, 1999 were analyzed. Twenty-nine patients were considered as potential heart donors: 22 males and 7 females aged 33 +/- 3 years (Mean + SEM). The cause of brain death was head trauma in 17 cases (59%), cerebrovascular disease in 10 cases (34%), and cerebral anoxia related to cardiac arrest in 2 cases (7%). Eighteen hearts (18/29 or 66%) were harvested and transplanted with a favorable outcome at one month in 17 cases. In 11 cases, the heart was not harvested, nine (9/29 or 31%) because of myocardial dysfunction upon subsequent echocardiographic examination and 2 because of the lack of matched recipients. CONCLUSION: Comparison of these results with those of other groups suggests that hormonal substitution with insulin and triiodothyronine in the presence of myocardial dysfunction could be of potential interest to correct myocardial dysfunction and increase the number of donor hearts.

[Experimental pharmacology of atracurium dibesylate]. / Pharmacologie expérimentale du dibésylate d'atracurium.

Atracurium dibesylate is a new non depolarizing muscle relaxant, metabolized by a non enzymic pathway, the Hofmann elimination. The potency of atracurium in animals was similar to d-tubocurarine and six times less than that of pancuronium. In the cat, the ED50 was 130 micrograms . kg-1; an intravenous dose of 250 micrograms . kg-1 atracurium was sufficient to cause complete neuromuscular block; its duration was 29 min. Single twitch block was readily antagonized by neostigmine 50-100 micrograms . kg-1 or edrophonium 200 micrograms . kg-1. Halothane potentiated the block given by atracurium. Dose ratio for 50% vagal block (ED50) and 50% neuromuscular block was 24; atracurium had weak ganglioplegic effects. 2,000 micrograms . kg-1 atracurium (eight times the neuromuscular blocking dose) reduced mean aortic pressure, heart rate, cardiac output and peripheral resistance. Such effects could be prevented by giving histamine receptor blockers prior to injecting atracurium.

[Pharmacodynamics and safety of mivacurium in infants and children under halothane-nitrous oxide anesthesia]. / Pharmacodynamie et tolérance du mivacurium chez le nourrisson et l'enfant sous anesthésie par halothane-protoxyde d'azote.

OBJECTIVES: To determine pharmacodynamic effects and safety of mivacurium in paediatric patients. STUDY DESIGN: Multicentric, prospective, open, non-randomized study. PATIENTS: Forty-eight three-month-old to eight-year-old physical class ASA I or II children. METHOD: Anaesthesia was induced and maintained with halothane and nitrous oxide. Tracheal intubation was performed without a neuromuscular blocking agent. Neuromuscular blockade was measured with a strain force transducer after train-of-four stimulation of the ulnar nerve at the wrist every ten seconds. A single bolus dose of mivacurium (0.2 mg.kg-1) was injected during 15 seconds in patients allocated into three groups. Group 1: three to 12-month-old infants (n = 15), group 2: one- to three-year-old children (n = 16) and group 3: three- to eight-year-old children (n = 17). Onset and recovery parameters were measured in each patient. Heart rate and noninvasive arterial blood pressure were recorded every minute for five minutes after mivacurium injection. RESULTS: Following halothane administration for 29 and 32 min, and a FEThalothane = 1 vol%, mivacurium (0.2 mg.kg-1) determined a 100% neuromusmcular blockade in all patients. The onset time was 71 +/- 34 s (mean +/- SD) in all patients and did not differ between groups. Time to 25% and 95% recovery of the first twitch and recovery index for all the patients were 12 +/- 3 min, 19 +/- 5 min and 4 +/- 2 min respectively and did not differ between groups. No prolonged paralysis was observed. No significant changes of HR and BP occurred. CONCLUSIONS: Following 0.2 mg.kg-1 of mivacurium in patients aged between three months to eight years, a complete blockade occurs with a rapid onset time and a short duration of action, without significant cardiovascular effect.

[Effects of propofol on blood concentration of cyclosporine]. / Effets du propofol sur les concentrations sanguines de ciclosporine.

OBJECTIVE: This study was designed to assess whether propofol modifies the blood concentrations of cyclosporine and lipoproteins, which bind cyclosporine. STUDY DESIGN: Prospective open study. PATIENTS: Fifteen consecutive grafted patients, scheduled for surgery allowing them to resume their oral treatment postoperatively. Their immunosuppressive treatment, included cyclosporine (Cy A), at a steady-state dosage. METHODS: Blood samples were drawn and residual Cy A blood concentrations were measured the days before and after anaesthesia and before and immediately after discontinuing the propofol infusion. Serum triglycerides, cholesterol, high-density lipoprotein (HDL) concentrations were measured before and immediately after discontinuing the propofol infusion. RESULTS: The 15 patients were given propofol by infusion for 30-210 min (mean 85 +/- 59 min). They received a total dose of propofol of 696 +/- 497 mg, a total fentanyl dose of 175 +/- 82 micrograms, and a total midazolam dose of 2.8 +/- 0.8 mg. The residual cyclosporine blood concentrations were similar the day before (142 +/- 47 ng.mL-1) and following anaesthesia (128 +/- 46 ng.mL-1) (P = 0.08). Serum cholesterol concentrations were not significantly influenced by propofol infusion, but serum triglycerides levels increased (1.46 +/- 0.66 vs 1.97 +/- 0.81 g.L-1), and HDL and LDL levels decreased (0.54 +/- 0.20 vs 0.47 +/- 0.18 g.L-1; 1.44 +/- 0.42 vs 1.28 +/- 0.37 g.L-1). CONCLUSION: Propofol by infusion does not modify the cyclosporine concentration. It is concluded that propofol may be a suitable agent for intravenous anaesthesia in cyclosporine treated patients, provided a close postoperative monitoring of cyclosporine blood concentrations is maintained.

[Determination of the dose-response curve for atracurium dibesylate in the anesthetized adult]. / Détermination de la courbe dose-effet du dibésylate d'atracurium chez l'homme adulte anesthésié.

The mechanical response of the adductor pollicis to a 0.15 Hz stimulation of the ulnar nerve was studied in 35 unpremedicated adult patients (mean age 38 yr) under general anaesthesia using thiopentone, fentanyl and a N2O/O2 mixture under mechanical ventilation. PaCO2, pH, K, Ca, Mg plasma levels and temperature were in the normal range. Each patient received a single bolus of atracurium dibesylate: 0.10 mg . kg-1 (n = 11), 0.15 mg . kg-1 (n = 10), 0.20 mg . kg-1 (n = 11) or 0.30 mg . kg-1 (n = 4). The dose-response curve was constructed using the log-probit method for 0.10, 0.15, 0.20 mg . kg-1 doses, giving neuromuscular blocks greater than 0% and less than 0.20 mg . kg-1. The 0.20 mg . kg-1 dose had an onset time of 6.1 +/- 0.6 min, duration 0-90% of 34.3 +/- 3.2 min and a recovery index 25-75% of 10.9 +/- 1.0 min. The 0.3 mg . kg-1 dose resulted in onset time of 4.7 +/- 1.3 min, duration of 39.9 +/- 3.7 min and a recovery index of 10.7 +/- 1.8 min. Thus atracurium dibesylate seemed to be an agent of intermediate potency. Onset time was approximately the same as that for other non-depolarizing neuromuscular blocking drugs, but duration of action and recovery index were quite shorter, except for vecuronium bromide.

[Analysis of the criteria that contribute to the decision to harvest the heart in brain-dead organ donors]. / Analyse des critères qui participent à la décision de prélèvement cardiaque chez les patients en état de mort encéphalique.

OBJECTIVES: The number of cardiac transplantation procedures does not increase because of the lack of donor hearts despite an increase in the number of brain-dead organ donors. The criteria used to select a donor heart are not formally standardized. The aim of the present study was to analyze the criteria that contribute to the selection of a donor heart. TYPE OF STUDY: Descriptive, retrospective study. PATIENTS AND METHOD: Clinical parameters, the initial causes that lead to brain death, maximum doses of catecholamines, several biochemical markers of myocardial ischaemia/necrosis as well as several echocardiography criteria were extracted from a prospectively collected database. Univariate and multivariate (logistic regression) analyses were performed with the "harvested heart" as dependent variable and the above-cited independent variables. RESULTS: One hundred and eighty consecutive brain-dead patients admitted from 1st October 1998 to 31st December 2000 out of which 112 gave at least one organ were analyzed. Among these 112 patients, 59 (39 males and 20 females) were pre-selected as potential heart donors. Only 44 hearts were harvested. Logistic regression analysis showed that harvesting of the heart was more probable if the donor were a male, had no left ventricle systolic wall motion abnormalities, had low doses of norepinephrine and low serum troponin Ic concentrations. CONCLUSION: After an initial phase of selection, the final decision to harvest a heart is based on several criteria. These results should be an incentive to conceive a score that could allow a more formal decision process for heart harvesting.

[Peri-operative anticoagulation with danaparoid for a patient with Budd-Chiari syndrome and heparin-induced thrombocytopenia]. / Anticoagulation péri-opératoire par danaparoïde (Orgaran) chez un patient ayant un syndrome de Budd-Chiari et une thrombopénie induite par l'héparine.

We report a case of Budd-Chiari syndrome revealing a polycythemia vera and complicated by heparin-induced thrombocytopenia. A surgical porto-caval shunt was inserted with danaparoid as anticoagulant during the peri-operative period. The doses of danaparoid were as follows: a continuous intravenous infusion of 200 U/h with a target between 0.5 et 0.8 U/ml antifactor Xa activity during the preoperative period, followed by 100 U/h with a target of 0.3 U/ml during the peroperative period; an increase in doses of danaparoid to 150 and 200 U/h with a target above 0.5 U/ml was used during the postoperative period. This case report is a rare situation of hypercoagulable state, in a surgical context, treated with danaparoid.

[Prolonged phase II neuromuscular blockade following succinylcholine administration]. / Bloc dépolarisant de phase II et curarisation prolongée après un bolus de succinylcholine.

Patients who are given a single dose of succinylcholine normally undergo a short-acting depolarizing phase I neuromuscular block but rarely a phase II block. Prolonged neuromuscular blockade occurs after a single dose of succinylcholine in case of genetically determined abnormal plasma butyrylcholinesterase activity. It is mandatory to use monitoring to detect this side effect. We report a case of a patient with abnormal plasma butyrylcholinesterase activity undergoing a six-hour prolonged neuromuscular phase II block, after a single dose of succinylcholine.

[Fast recovery of haemodynamic and ventilatory functions after sugammadex bolus following rocuronium-induced anaphylactic shock refractory to conventional treatment]. / Récupération hémodynamique et ventilatoire rapide après injection de sugammadex lors d'un choc anaphylactique au rocuronium, réfractaire au traitement conventionnel.

Recently, three case reports have suggested the possible efficacy of sugammadex in anaphylactic shock refractory to conventional treatment induced by rocuronium. We report a new case of severe anaphylactic reaction to rocuronium treated with sugammadex. After 18 minutes of conventional treatment because of persistent cardiocirculatory failure and bronchospasm, a bolus of 2000 mg (18 mg/kg) of sugammadex was injected. This was associated with rapid correction of arterial hypotension and bronchoconstriction. The underlying pathophysiological mechanisms that explain the potential beneficial effect of sugammadex in this context are unknown but it is important to know that refractory anaphylactic shock to rocuronium can be potentially corrected with sugammadex.

[Prolonged residual paralysis after a single intubating dose of rocuronium: an unexpected cause]. / Bloc résiduel prolongé après injection unique de rocuronium pour l'intubation : une étiologie originale.

Postoperative curarization following a single dose of rocuronium is a known risk quickly diagnosed through the monitoring of neuromuscular blockade. Different etiologies can cause a prolonged block. We report the case of a misdiagnosis of prolonged neuromuscular blockade by a failure in the monitoring system of curarization.