Anaphylactic reactions during induction of anaesthesia using rocuronium for muscle relaxation: a report including 3 cases

Anaphylaxis during induction of anaesthesia is a dreaded complication with a mortality rate of 3-6%, most frequently associated with the use of muscle relaxants. Current knowledge on this matter is reviewed in relation to the presentation of 3 cases of anaphylaxis and bronchospasm associated with the use of the recently released nondepolarizing muscle relaxant rocuronium. Bronchospasm may be the sole sign of a serious drug reaction, triggered by precipitation of insoluble thiopental crystals when mixed with a muscle relaxant in the intravenous (iv) line. It is recommended that these drugs are administered via different injection ports. The hypotension requires immediate treatment with oxygen, epinephrine and large amounts of iv fluids. Epinephrine infusion may be needed for hours. It is recommended that serum tryptase is measured approximately 2 h after debut of the serious drug reaction. Allergy testing should be performed for all the drugs the patient was exposed to, 4-8 weeks after the incident, and due to cross-reactivity, including all available muscle relaxants. Doctors are urged to inform their patients, and systematically register adverse drug reactions.     

The risk of anaphylactic reactions to rocuronium in the United States is comparable to that of vecuronium: an analysis of food and drug administration reporting of adverse events

Published reports from France and Norway suggest a frequent incidence of anaphylaxis to rocuronium and have raised concerns about its safety. We hypothesized that the Food and Drug Administration Adverse Event Reporting System could be used to confirm whether there has been an unusual incidence of anaphylactic events for rocuronium in the United States (U.S.) and whether the reporting patterns differ within and outside of the U.S.. We queried the Food and Drug Administration Adverse Event Reporting System for 1999 through the first quarter of 2002 for all adverse events for the drugs rocuronium and vecuronium and then searched on the terms considered to represent possible anaphylaxis using proprietary software. We compared the frequency of these terms in data both for rocuronium and vecuronium. We then assessed the occurrence of reports of anaphylaxis-related terms in reports from the U.S. compared with reports originating outside of the U.S.. For rocuronium, the database contained 311 reports, 166 domestic and 145 from foreign sources. Fifty percent of the foreign reports contained an anaphylaxis term versus 20% of the domestic reports (P < 0.001). For vecuronium, the comparable figures were 17% and 19% (not significant) and the total number of reports was 243. The incidence of the reports containing anaphylaxis terms did not differ between vecuronium and rocuronium in the U.S. but were significantly different for foreign reports (P < 0.001). These data confirm that U.S. anesthesia providers have not observed a significant difference in anaphylactic reactions between the two commonly used intermediate-acting muscle relaxants and suggest that frequency of reports of anaphylaxis may be significantly influenced by the area from which the reports originate.     

Prospective preoperative survey of 300 patients using prick tests with muscle relaxants

It is now well established that the retrospective diagnosis of anaphylaxis to muscle relaxants may be based on skin prick testing. These tests, which use undiluted solutions of muscle relaxants, are as sensitive, specific and reproducible as intradermal tests for the diagnosis of IgE related adverse reactions to muscle relaxants. The rate of muscle relaxant anaphylaxis (1/1 500 to 1/5 000) justifies its prevention based on a possible latent sensitization. A prospective investigation was carried out in 300 surgical patients scheduled for general anaesthesia. Prick tests were carried out using the 6 available muscle relaxants: suxamethonium, gallamine, alcuronium, pancuronium, vecuronium and atracurium. The wheal the drug might produce was compared with that obtained with codeine phosphate (a histamine releasing drug). Thirty-seven patients (13%) were considered to be atopic; 262 (87%) had undergone a previous anaesthesia. Three percent (n = 11) of tests were positive for atracurium. The wheal produced by atracurium was in favour of non-specific histamine release. One test was found positive for suxamethonium. Confirmation of this probable latent sensitization was unfortunately not possible. There were no other positive skin tests. Muscle relaxants were subsequently used in 58 patients (80% vecuronium) without any problem. Skin prick testing should be used on a larger scale to detect latent sensitization. However, predictive skin tests with atracurium should be avoided, as wheal reactions with this drug are probably due to non-specific histamine release.     

Epidemiology of anesthetic anaphylactoid reactions. Fourth multicenter survey (July 1994-December 1996)]

Since 1984 an epidemiological survey of anaphylactoid reactions occurring during anaesthesia has been obtained in France with regular repeated inquiries by the Perioperative Anaphylactoid Reactions Study Group (Gerap). The members of this group collected during the study period cases of patients having suffered from an anaphylactoid reaction and subsequently tested in their allergoanaesthetic outpatient clinic. The three previous surveys published in the Annales fran?aises d'anesthésie et de réanimation in 1990, 1993 (in English) and 1996 included 1,240, 1,585 and 1,730 patients respectively. The current survey concerned 1,648 patients, tested by the GERAP (38 diagnostic centres) from July 1994 to December 1996. The diagnostic tests for IgE anaphylaxis were cutaneous tests (prick tests and intradermal tests), which minimal dilutions for specific positive skin test were previously determined by comparison with control subjects. The cutaneous tests were performed by all the centres. These tests were associated, in 29 centres, with the detection of specific IgEs against quaternary ammonium compound and inhibition test, and detection of IgEs against propofol, thiopental and latex. Moreover, leukocyte histamine release test was performed in seven centres. The mechanism of the reaction was: anaphylaxis in 692 patients (characteristic clinical symptoms and positive allergological tests), anaphylactoid reactions in 611 patients (characteristic clinical symptoms and negative allergological tests), and other causes in 345 patients (unusual clinical symptoms and negative allergological tests). An immune mechanism was found in 53% of the reactions, with characteristic clinical symptoms occurring during anaesthesia. The 692 cases of anaphylaxis were due to 734 substances (double anaphylaxis in 42 patients): muscle relaxants (61.6%), latex (16.6%), antibiotics (8.3%), hypnotics (5.1%), colloids (3.1%), opioids (2.7%) and others (2.6%) among which aprotinin (four cases) ethylene oxide (five cases) local anaesthetics (two cases). The muscle relaxants implicated in anaphylactic reactions included: vecuronium (n = 130), atracurium (n = 107), suxamethonium (n = 106), pancuronium (n = 41), rocuronium (n = 41), mivacurium (n = 18), and gallamine (n = 9). These results reflected French anaesthetic practice, except for suxamethonium (5% of the French market share of curares). In 70% of the patients who were allergic to one muscle relaxant, cross-sensitivity was found with the other relaxants. The comparison with the three previous surveys confirms that the mechanism of about half of the anaphylatoid reactions occurring during anaesthesia is of immune origin, due to specific IgE antibodies. Muscle relaxants remain the most common cause of anaphylaxis, followed by latex whose incidence seems to decrease, whereas the incidence of anaphylaxis to antibiotics increases. Incidence of reactions to suxamethonium decreased, corresponding however to one quarter of all muscle relaxant anaphylaxis, similar with vecuronium and atracurium. For this survey, more clinical information was obtained in 583 patients, allowing the following conclusions: reactions were always more severe in case of anaphylaxis than nonspecific histamine release; reactions occurred more frequently in females (F/M = 2.5); 17% of patients allergic to a muscle relaxant were never anaesthetized beforehand; a history of reactions during previous anaesthetics was a risk factor for a reaction during subsequent anaesthetics; neither drug allergy nor atopy (except for latex allergy) were a predisposing factor for reactions with anaesthetic agents. Considering that in 1996, 8 million anaesthetics were administered in France, of which 2.5 million included the use of muscle relaxants, the overall incidence for anaphylactic reactions, all agents included, was evaluated as 1 in 13,000 anaesthetics, while the incidence of anaphylaxis to muscle relaxants was 1 in 6,500 anaesthetics.     

Anaphylaxis to muscle relaxants: an audit of ten years of allergy testing at the Royal Adelaide Hospital

We audited patients with anaphylaxis to muscle relaxants during anaesthesia referred to the Department of Anaesthesia at the Royal Adelaide Hospital between the start of 2000 and the end of 2009. Of the 220 patients tested during this period, 43 had a positive intradermal test to the muscle relaxant given during their anaesthetic. The majority of these were to rocuronium and suxamethonium. Where rocuronium was the index agent, 65% of patients cross-reacted with another relaxant and 29% of patients with suxamethonium as their index agent demonstrated cross-reaction with another relaxant.     

Rocuronium and cisatracurium-positive skin tests in non-allergic volunteers: determination of drug concentration thresholds using a dilution titration technique

BACKGROUND: Muscle relaxants are believed to be responsible for 2/3 of the cases of anaphylactic reactions during anesthesia. This assumption is based mainly on positive skin tests obtained in individuals that have experienced anesthesia-related anaphylaxis. A positive skin test is supposed to be associated with mast cell degranulation of vasoactive amines. In the present study we tested the frequency of positive skin tests with two commonly used muscle relaxants, rocuronium and cisatracurium, in a selected group of volunteers with low potential for allergic reactions. METHODS: Thirty healthy volunteers without known allergy or previous exposure to muscle relaxants were studied. Low potential for allergic reactions was determined prior to inclusion in the study, using various allergy tests. Each individual was tested with intradermal and skin prick tests, and molar drug concentration thresholds for positive skin reactions were determined using a dilution titration technique. The presence or absence of mast cell degranulation was tested by electron microscopic investigation of skin biopsies obtained from positive and negative skin reactions. RESULTS: None of the volunteers had a positive skin prick test. More than 90% of the volunteers had a positive intradermal test with both rocuronium and cisatracurium. The highest molar drug concentration that was not associated with a positive intradermal test was 10(-6) M (rocuronium) and 10(-7) M (cisatracurium), equivalent to vial dilution 1 : 1000 for both drugs. In none of the volunteers was mast cell degranulation detected. CONCLUSION: Non-mast-cell-mediated positive intradermal skin reactions are frequently occurring with rocuronium and cisatracurium, even at vial dilution 1 : 1000. A clinically applicable test technique is needed that is able to separate positive skin tests associated with mast cell degranulation from non-mast-cell-mediated reactions.     

Sugammadex and rocuronium-induced anaphylaxis

Perioperative anaphylaxis is a life-threatening clinical condition that is typically the result of drugs or substances used for anesthesia or surgery. The most common cause of anaphylaxis during anesthesia is reportedly neuromuscular blocking agents. Of the many muscle relaxants that are clinically available, rocuronium is becoming popular in many countries. Recent studies have demonstrated that succinylcholine (but also rocuronium use) is associated with a relatively high rate of IgE-mediated anaphylaxis compared with other muscle relaxant agents. Sugammadex is widely used for reversal of the effects of steroidal neuromuscular blocking agents, such as rocuronium and vecuronium. Confirmed cases of allergic reactions to clinical doses of sugammadex have also been recently reported. Given these circumstances, the number of cases of hypersensitivity to either sugammadex or rocuronium is likely to increase. Thus, anesthesiologists should be familiar with the epidemiology, mechanisms, and clinical presentations of anaphylaxis induced by these drugs. In this review, we focus on the diagnosis and treatment of anaphylaxis to sugammadex and neuromuscular blocking agents. Moreover, we discuss recent studies in this field, including the diagnostic utility of flow cytometry and improvement of rocuronium-induced anaphylaxis with the use of sugammadex.     

Muscle weakness after muscle relaxants: an audit of clinical practice

Residual muscle weakness after general anaesthesia, assessed using handgrip strength, was audited in a teaching hospital. The relationships between residual weakness, the use of muscle relaxants and patient characteristics were examined. Handgrip strength was measured preoperatively, one hour postoperatively and one day postoperatively using a hand dynamometer in 151 patients having general anaesthesia. Forty-nine patients received no muscle relaxant, 34 patients received vecuronium and 68 received rocuronium. Patients were managed by their anaesthetist according to that anaesthetist's clinical choice. All patients who received muscle relaxants received neostigmine. One hour postoperatively, there was a decline in handgrip strength of 16% for the no relaxant group, 24% for vecuronium and 29% for rocuronium. The degree of weakness for the relaxant groups was unrelated to age (P=0.89) but was strongly influenced by the patient's sex. Almost all of the increased weakness with relaxants was found in the female patients. The mean decline in handgrip strength in the male patients who received either vecuronium or rocuronium was similar to that seen when relaxants had not been used (P=0.40). One hour postoperatively, female patients showed a marked decrease in handgrip strength after both vecuronium and rocuronium (32% and 34% respectively, combined P=0.01). These results suggest that in usual clinical practice at our institution, female patients are more likely to have residual weakness after muscle relaxants.     

新型肌肉松弛药拮抗剂舒更葡糖钠在麻醉苏醒期应用的近况

舒更葡糖钠是拮抗非去极化肌肉松弛药（肌松药）的新型药物,它能够快速、安全、可控地拮抗罗库溴铵等甾体类肌松药的神经肌肉阻滞,与传统肌松拮抗剂抗胆碱酯酶药相比,具有拮抗深度神经肌肉阻滞且不影响胆碱能系统活性的优越性,在麻醉苏醒期的临床应用具有广泛前景。文章通过对新型肌松拮抗药舒更葡糖钠的作用机制、使用效能、在特殊患者中的应...     

Sugammadex in the management of rocuronium-induced anaphylaxis

Anaphylaxis during anaesthesia is a rare event that in ～60-70% of cases is secondary to neuromuscular blocking agents. It has been suggested previously that the recent introduction of sugammadex may provide a novel therapeutic approach to the management of rocuronium-induced anaphylaxis. We describe the case of a 33-yr-old female who suffered a severe anaphylactic reaction to rocuronium, presenting with cardiovascular collapse on induction of anaesthesia. After 19 min of traditional management, she was given a bolus of sugammadex 500 mg. This was associated with an improvement in the adverse haemodynamic state. The underlying reasons for this are unclear, but sugammadex may potentially be a useful adjunct in the management of rocuronium-induced anaphylaxis.     

Rocuronium anaphylaxis and multiple neuromuscular blocking drug sensitivities

PURPOSE: To report a case of anaphylaxis to rocuronium and the sensitivities to multiple neuromuscular blocking drugs in a patient with no previous exposure to this group of drugs. We describe the current recommendations for both intraoperative and postoperative testing of these patients. CLINICAL FEATURES: A 36-yr-old man was admitted for repair of a ruptured Achilles tendon. Following induction of general anesthesia with fentanyl and propofol, 60 mg of rocuronium were given to facilitate tracheal intubation. He immediately became profoundly hypotensive with impalpable pulses, and blood pressure could not be recorded. Airway pressure increased markedly, and hand ventilation of the lungs became very difficult. His airway was secured and he was successfully resuscitated with 3 mg epinephrine and three litres crystalloid and colloid intravenous fluid therapy. His recovery in the intensive care unit was uneventful and the operation was performed four days later under spinal anesthesia. Subsequent skin prick testing, performed six weeks later, demonstrated strong positive weal and flare reactions to rocuronium, vecuronium and pancuronium, and some cross-reactivity with the benzylisoquinolinium group of muscle relaxants. CONCLUSION: Muscle relaxants are responsible for 61.6% of cases of anaphylaxis during general anesthesia. Cross-reactivity is common, as this group of drugs share a quaternary ammonium group. It is mandatory that patients be tested for both the agent responsible and cross-reactivity following an anaphylactic response. We suggest a protocol for investigation of suspected anaphylaxis.     

Hypersensitivity reactions and deaths associated with intravenous iron preparations.

BACKGROUND: Parenteral iron therapy is an accepted adjunctive management of anaemia in kidney disease. Newer agents may have fewer severe hypersensitivity adverse events (AE) compared with iron dextrans (ID). The rate of type 1 AE to iron sucrose (IS) and sodium ferric gluconate (SFG) relative to ID is unclear. We used the US Food and Drug Administration's Freedom of Information (FOI) surveillance database to compare the type 1 AE profiles for the three intravenous iron preparations available in the United States. METHODS: We tabulated reports received by the FOI database between January 1997 and September 2002, and calculated 100 mg dose equivalents for the treated population for each agent. We developed four clinical categories describing hypersensitivity AE (anaphylaxis, anaphylactoid reaction, urticaria and angioedema) and an algorithm describing anaphylaxis, for specific analyses. RESULTS: All-event reporting rates were 29.2, 10.5 and 4.2 reports/million 100 mg dose equivalents, while all-fatal-event reporting rates were 1.4, 0.6 and 0.0 reports/million 100 mg dose equivalents for ID, SFG and IS, respectively. ID had the highest reporting rates in all four clinical categories and the anaphylaxis algorithm. SFG had intermediate reporting rates for urticaria, anaphylactoid reaction and the anaphylaxis algorithm, and a zero reporting rate for the anaphylaxis clinical category. IS had either the lowest or a zero reporting rate in all clinical categories/algorithm. CONCLUSIONS: These findings confirm a higher risk for AE, especially serious type 1 reactions, with ID therapy than with newer intravenous iron products and also suggest that IS carries the lowest risk for hypersensitivity reactions.     

Prevention of succinylcholine-induced fasciculation and myalgia: a meta-analysis of randomized trials

Fifty-two randomized trials (5,318 patients) were included in this meta-analysis. In controls, the incidence of fasciculation was 95%, and the incidence of myalgia at 24 h was 50%. Nondepolarizing muscle relaxants, lidocaine, or magnesium prevented fasciculation (number needed to treat, 1.2-2.5). Best prevention of myalgia was with nonsteroidal antiinflammatory drugs (number needed to treat, 2.5) and with rocuronium or lidocaine (number needed to treat, 3). There was a dose-dependent risk of blurred vision, diplopia, voice disorders, and difficulty in breathing and swallowing (number needed to harm, < 3.5) with muscle relaxants. There was evidence of less myalgia with 1.5 mg/kg succinylcholine (compared with 1 mg/kg). Opioids had no impact. Succinylcholine-induced fasciculation may best be prevented with muscle relaxants, lidocaine, or magnesium. Myalgia may best be prevented with muscle relaxants, lidocaine, or nonsteroidal antiinflammatory drugs. The risk of potentially serious adverse events with muscle relaxants is not negligible. Data that allow for a risk-benefit assessment are lacking for other drugs.     

Adverse drug reactions

Adverse drug reactions are unwanted reactions to drugs that occur under normal conditions of use, and are probably responsible for 3–5% of all hospital admissions. They are usually classified as Type A (augmented) or Type B (bizarre) reactions. Type A reactions are responsible for 80–90% of all adverse responses to drugs. They are relatively common, well known, and predictable, and have a close temporal relation with drug administration. Although patients vary in their susceptibility, most Type A reactions occur in every patient who is given the drug in sufficient dose. Type B reactions are usually unrelated to the main effects of drugs; they are often dose-independent, uncommon and unpredictable. Although their cause may be obscure, they are sometimes related to genetic predisposition or drug hypersensitivity. In anaesthetic practice, at least three important Type B reactions are directly related to genetic predisposition (malignant hyperthermia, suxamethonium apnoea, hepatic porphyria). Hypersensitivity or allergic responses to drugs depend on immunological factors; there are four types, depending on the mechanism involved. Most severe allergic reactions to drugs are a result of Type I hypersensitivity (anaphylaxis). In anaesthesia, the main aetiological factors are muscle relaxants, antibiotics, latex rubber and chlorhexidine; reactions to these agents may cause hypotension, bronchospasm, facial and laryngeal oedema, or urticaria. Similar effects occur when histamine and other factors are directly released from mast cells by non-immunological mechanisms (anaphylactoid reactions). Finally, drugs that are given during pregnancy may cross the placental barrier and adversely affect the fetus.     

The preoperative detection of risk of anaphylaxis during anaesthesia

In 144 patients who were referred to an anaesthetic allergy clinic because of perceived risk of anaphylaxis during anaesthesia, the only 'at risk' group that could be identified was patients with a history of unexplained severe adverse reaction during previous anaesthesia. Twenty-two of 45 patients with such a history had positive skin tests to an anaesthetic drug. Twenty-one positive tests were to neuromuscular blocking drugs and one to an opiate. In 18 of these patients the medical records were available and an adverse event had been recorded consistent with anaphylaxis. On the contrary, investigation of patients without a previous adverse reaction did not appear to be of value. These findings suggest that those patients with a history of a severe undiagnosed adverse event during previous anaesthesia should be investigated with preoperative skin-testing before undergoing further elective surgery.     

Substances responsables des chocs anaphylactiques peranesthésiques. Troisième enquête multicentrique française (1992–1994)

Since 1989, the epidemiological survey of anaphylactoid reactions occurring during anaesthesia is obtained in France with repeated inquiries by the Perioperative Anaphylactic Reactions Study Group. The members of this group collect during the study period the cases of patients having suffered from an anaphylactoid reaction and tested in their allergo-anaesthetic outpatient clinic, their characteristics (age, gender), the results of the allergological tests (mechanism, agents responsible for the reactions). The two previous surveys published in the Annales françaises d'anesthésie et de réanimation in 1990 and 1993 included 1,240 and 1,585 patients respectively. The current survey concerned 1,750 patients tested in 27 diagnostic centres, from January 1992 to June 1994.The reactions occurred at all ages, predominantly between 10 and 50 years, the sex-ratio (F/M) was 2.4. Allergological tests carried out to diagnose an immune mechanism for the shock were cutaneous tests in all centres (prick-tests in 21 centres, intradermal tests in 27 centres) using the same dilutions for the tested agents and the same threshold for positivity. Specific IgE antibodies against muscle relaxants, thiopentone and propofol, were measured by radio immunoassays in 20 centres. The leucocyte histamine release test was used in 10 centres. The immune origin of the shock — IgE dependent anaphylaxis — was diagnosed in 1,000 patients (57.8%) and due to 1,030 agents: muscle relaxants (59.2%), latex (19%), hypnotics (5.9%), benzodiazepines (2.1%), opioids (3.5%), plasma substitutes (5.0%), antibiotics (3.1%) and other drugs given during anaesthesia such as aprotinine and protamine (2.2%). Suxamethonium was responsible for 39.3% of muscle relaxant anaphylaxis, vecuronium for 36%, atracurium for 14.5%, pancuronium for 4.8%, gallamine for 3.1% and alcuronium for 2.3%. The latter has been withdrawn from the French market in 1993. These differences in the incidence of reactions are correlated with the clinical use of muscle relaxants in France for vecuronium and atracurium, however not for suxamethonium, responsible for 39% of the reactions but representing only 5% of the muscle relaxants sold in France.The comparison with the two previous surveys confirms that the mechanism of more than half of the anaphylactoid reactions occurring during anaesthesia is of immune origin, due to specific IgE antibodies. It is therefore essential to systematically carry out an allergologic assessment several weeks after the reaction, in order to discard for the subsequent anaestheticts the agent (s) responsible for anaphylaxis. If the muscle relaxants remain the first drugs involved in shock occurring at induction, there is a significant increase in latex shock, as demonstrated by the three epidemiological surveys (0.5%, 12.5 and now 19%). The incidence of other anaesthetic agents, antibiotics and plasma substitutes remains unchanged.     

BENZODIAZEPINES AS ORAL PREMEDICANTS

The advantages of the benzodiazepines as oral premedicants are:clear anxiolytic and sedative effect; less clear amnesic actionwhich may prevent the recall of the time spent lying on an uncomfortabletheatre trolley, but not necessarily recall of the journey tothe operating theatre, or induction of anaesthesia; convenientroute of administration; long duration of action of 5–8h which simplifies timing of drug administration; adverse autonomic,hormonal and circulatory system reactions seem to be prevented,thus preventing the stress reaction even before induction ofanaesthesia; anticonvulsant and muscle-relaxing actions maybe of value in patients receiving local anaesthesia, or in preventingthe side-effects of depolarizing muscle relaxants; nausea beforeand after operation may be decreased; reduced frequency of side-effectsbefore and after operation.     

Magnesium‐induced recurarisation after reversal of rocuronium‐induced neuromuscular block with sugammadex

A 61‐year‐old woman (57 kg, 171 cm) underwent surgery under general anaesthesia with desflurane 5.8–6.1 vol. % end‐tidal, remifentanil 0.2–0.4 μg/kg/min and rocuronium 35 mg (0.61 mg/kg). On return of the second twitch in the train‐of‐four (TOF) stimulation measured by acceleromyography, sugammadex 120 mg (2.1 mg/kg) was given. After complete neuromuscular recovery, magnesium sulphate 3600 mg (60 mg/kg) was injected intravenously over 5 min to treat atrial fibrillation. This was associated with recurarisation with a nadir [first twitch = 25%, TOF ratio (TOFR) = 67%] 7 min after the start of the magnesium sulphate infusion (magnesium plasma level: 2.67 mM). A spontaneous twitch value and a TOFR of > 90% were observed 45 min after the beginning of the magnesium sulphate infusion under general anaesthesia. Rapid infusion of magnesium sulphate may re‐establish a sugammadex‐reversed, rocuronium‐induced neuromuscular block during general anaesthesia, probably because of the high plasma level of magnesium (2.67 mM). Desflurane and a small fraction of unbound rocuronium may amplify the known muscle relaxing effects of magnesium. Intravenous injection of magnesium sulphate is not recommended in patients after general anaesthesia with neuromuscular relaxants, particularly after sugammadex reversal. Quantitative neuromuscular monitoring should be used for reversing aminosteroid muscle relaxants with sugammadex ? particularly in combination with magnesium injection ? to prevent post‐operative residual curarisation.     

Remifentanil and propofol without muscle relaxants or with different doses of rocuronium for tracheal intubation in outpatient anaesthesia

BACKGROUND: The use of muscle relaxants in outpatient anaesthesia is controversial; some authors recommend an induction regimen including propofol and opioids without muscle relaxants. This study evaluated the requirements for rocuronium after remifentanil/propofol. METHODS: We examined in four groups of ASA I-II patients (n= 30 for each) the intubating conditions three minutes after induction of anaesthesia with remifentanil 0.5 microg kg(-1) min(-1), propofol 2 mg kg(-1) without muscle relaxants or with different doses of rocuronium (0.6 mg kg(-1), 0.45 mg kg(-1), 0.3 mg kg(-1)) applying the criteria proposed by the Copenhagen Consensus Conference. In the second part of the study the time course of neuromuscular block was determined by electromyography using train-of-four (TOF) stimulation. To this end, another 60 ASA I-II patients were randomly assigned to receive remifentanil 0.5 microg kg(-1) min(-1), propofol 2 mg kg(-1) and either rocuronium 0.6 mg kg(-1), 0.45 mg kg(-1), 0.3 mg kg(-1), or 0.3 mg kg(-1) followed by neostigmine 40 microg kg(-1) and atropine 20 microg kg(-1) at a T1 recovery of 10% (n=15 for each). RESULTS: Intubating conditions were good or excellent in 30 patients after rocuronium 0.6 mg kg(-1) and in 18 patients when rocuronium was omitted (P<0.01). After 0.45 mg kg(-1) and 0.3 mg kg(-1) rocuronium the numbers were 29 and 30 patients, respectively. Reducing rocuronium from 0.6 mg kg(-1) to 0.45 mg kg(-1) or 0.3 mg kg(-1) increased the onset time from 136 (35) s to 199 (34) s and 249 (52) s (mean (SD)), (P<0.01); the clinical duration decreased from 38 (10) min to 24 (8) min and 16 (5) min, respectively (P<0.01); and the duration to a TOF-ratio of 0.8 decreased from 60 (11) min to 45 (9) min and 34 (7) min (P<0.01). After rocuronium 0.3 mg kg(-1) this time interval further decreased to 22 (3) min when neostigmine was given at a T1 of 10% (P<0.01 compared with spontaneous recovery after rocuronium 0.3 mg kg(-1)). CONCLUSION: After remifentanil/propofol intubation conditions were poor in 40% of patients without muscle relaxants; adding reduced doses of rocuronium to this regimen improved the intubation conditions significantly. In addition, reducing the initial dose of rocuronium markedly shortened its time course of action.     

Rapid pre-operative immunotherapy in a patient allergic to muscle relaxants

Allergic reactions to muscle relaxants are not uncommon. Although, in most instances, divalent quaternary ammonium salts are involved in these reactions, some monovalent quaternary ammonium compounds can trigger IgE-mediated reactions. A woman who suffered from several episodes of anaphylaxis with divalent (suxamethonium) and monovalent quaternary ammonium salts (tiemonium) needed surgery. Regional anaesthesia was contra-indicated owing to a possible intolerance to local anaesthetics. Investigation confirmed an allergy to monovalent quaternary ammonium salts. Rapid immunotherapy was started with a monovalent quaternary ammonium salt (tiemonium) and subsequently followed by a general anaesthesia using vecuronium. The patient did not develop anaphylactic symptoms.