[Lack of sensitivity to per-anesthetic malignant hyperthermia in 32 patients who developed neuroleptic malignant syndrome]

The aim of this study was to verify whether a relationship exists between neuroleptic malignant syndrome (NMS) and anaesthetic-induced malignant hyperthermia (MH) or not. The in vitro halothane-caffeine tests were performed on muscle tissue obtained from 32 patients with documented NMS episodes. The diagnosis of NMS relied on Levenson's criteria. The results, expressed in accordance with the criteria of the European MH Group, defined 29 subjects as MH non-susceptible. Three patients were classified as MH equivocal. These findings demonstrate the lack of any link between NMS and MH. Therefore, patients with a history of NMS are not likely to be at risk of developing MH and special measures against MH are not required for anaesthesia in these patients.

[Subarachnoid hematoma after spinal anesthesia and low molecular weight heparin]

A case is reported of spinal subarachnoid haematoma occurring after spinal anaesthesia. The patient was given prophylactic pre and postoperative low molecular weight heparin. On the second postoperative day, he complained of backache and got a partial cauda equina syndrome. Magnetic resonance imaging carried out on the 6th day confirmed the presence of a spinal haematoma, which was removed surgically. One year later, the bilateral motor palsy which had involved several roots, had completely regressed. It remained a severe sensory loss associated with a loss of sphincter control. This case highlights the role of predisposing factors and the importance of early diagnosis.

[Accidental spinal anesthesia in obstetrics. Limits of epidural test-dose]

Two cases of accidental spinal anaesthesia occurring in obstetrical patients are reported and discussed. Epidural anaesthesia had been asked for by the women, both being free from any significant medical history. A Tuohy needle was inserted in the midline between L3 and L4 with the patient sitting. The extradural space was identified by the loss of resistance using saline. The test-dose (2 ml and 4 ml of 1% lignocaine respectively) was administered five minutes before changing the patient to the supine position. In the first case, after a test-dose had remained without any effect, 8 ml of 0.25% bupivacaine were injected, about one hour later. The patient rapidly complained of paralysis of her legs and difficulties in breathing. Her blood pressure decreased from 120/80 mmHg to 90/60 mmHg. The upper level of analgesia reached T4. She improved after infusion of 1.51 of lactated Ringer's solution. Endotracheal intubation was not required. Delivery was assisted with a vacuum extractor. In the other patient, when the extradural space had been located, there was a small reflux of clear fluid which did not contain any glucose. As the test-dose did not result in any effect. 2 ml of 2% lignocaine with adrenaline were injected. This was followed by an immediate sensory loss in the legs, extending up to T10. Caesarean section was decided on, without any further injections (foetal macrosomia, breech presentation). Both patients totally recovered without any sequela. Both children had an Apgar score of 10 at 1 and 5 minutes. The type of test-dose is discussed. Smaller volumes of more concentrated solutions are recommended.

[Obstetrical anesthesia of patients with disseminated lupus erythematosus]

The anaesthetic management of pregnant women who suffered from systemic lupus erythematosus (SLE) was reviewed retrospectively. During the ten-year period studied, there were nineteen pregnancies in eighteen women (mean age 27 years) who had either SLE or an isolated lupus type anticoagulant (LAF). Four pregnancies were stopped before the third trimester, two spontaneously, and the other two because of the mother's condition. Of the fifteen remaining pregnancies, eight children were born with a weight less than 2,500 g. One child, birth weight 750 g, died after three days. None of the fourteen living children had neonatal lupus. Six epidural and twelve general anaesthetics were carried out for four abortions, nine Caesarian sections, and five deliveries. Epidural anaesthesia was often contraindicated by neurological and haemostatic complications of the SLE: recent meningitis, thrombocytopaenia, prolonged bleeding, anticoagulant therapy. In fact, management of SLE patients required extensive preanaesthetic clinical and paraclinical assessment, as all the systems may be involved in this condition; moreover, it may worsen during pregnancy (seven times in this series). The most frequent complications were cardiovascular, renal, and haematological. Possible intubation difficulties must also be looked for. A LAF was associated with a great number of venous thromboses. An isolated LAF does not contraindicate epidural anaesthesia, as long as there is no associated haemostatic defect, such as a thrombocytopaenia. Furthermore, the patient should not have had prolonged episodes of unexplained bleeding, or require anticoagulants. In the present series, epidural anaesthesia was contraindicated in three of the four patients with LAF. Finally, prevention of thromboembolism, postoperative infection and adrenal failure (in those patients with long-term steroid therapy) must be carried out.

[Intravascular volume expansion and intravenous nimodipine in the treatment of cerebral vasospasm after surgical treatment of intracranial aneurysm]

The advantage of calcium antagonist on cerebral arterial spasm during the peri-operative period has been recently demonstrated. However, the role of volemia and cardiac output in the pathogenesis of arterial spasm seems predominant. The basal hemodynamic profile of 17 patients operated for an intracranial aneurysm was investigated. The hemodynamic and neurological modifications induced by treatment with nimodipine, modification of blood volume and the use of inotropic drug was subsequently analysed. In 8 patients there was a clearcut hypovolemia with diminished cardiac index whereas in 9 other patients there were low filling pressures with an unmodified cardiac index. As early as the 48th hour of treatment, there was an improvement of Hunt and Hess score in 12 patients whereas in 5 others the score remained unchanged. Two death occurred due to the extension of secondary ischemic lesions. This study seems to confirm the aggravating role of hypovolemia in the occurrence of vasospasm and the neurological improvement due to the association of a calcium antagonist, restoration of blood volume with or without a vasoconstrictor.

[Diagnosis of susceptibility to malignant hyperthermia in children]

The realisation and reliability of the halothane-caffeine contracture tests in children to detect the susceptibility to malignant hyperthermia (MH) is still controversial. The present study concerned 26 children aged 2 to 13 years, (mean 9.5 +/- 1.3 years) who were tested either because of a personal symptomatology (14 cases) or as a member of a susceptible MH family (12 cases). Half of the children had a positive test (MHS and MHE) as is found in adults. Furthermore comparison of threshold concentrations of halothane and caffeine as well as the 32 nmol caffeine-induced contractures dit not show significant differences related to age. These results support the possibility to perform under good conditions and with good reliability the diagnostic test of susceptibility to malignant hyperthermia in children from 2 years on.

[Peridural anesthesia for all women in labor: utopia or reality?]

Peridural anesthesia in obstetrics is more and more widely used, improving comfort and security for delivery. In 1989, 74% of the deliveries occurred under peridural anesthesia in our unit. In order to assess if this percentage can be increased, we analysed during one month the reasons why some women did not get a peridural anesthesia.

[Anesthetic technics for the difficult intubation]

Numerous anaesthetic techniques exist for a patient who presents with a difficult endotracheal intubation. They all require an anaesthetic protocol which cannot be improvised. When intubation is expected to be difficult at the pre-anaesthetic examination, the use of a fiberoptic bronchoscope is the technique of choice for intubating adults under local anaesthesia, and children under general anaesthesia. When a fiberoptic bronchoscope is not available, several alternatives can be suggested: local anaesthesia of the glottis, retro-molar and retrograde intubation, or the use of a guide threaded over a lighted stylet; these techniques can be used in an anaesthetized patient breathing spontaneously. In the paralyzed patient impossible to intubate, various trans-laryngeal techniques of ventilation can be used in emergency: jet ventilation via the trans-crico-thyroid route, the use of a cricotomy cannula, or a minitracheotomy set.

Effect of propofol on the malignant hyperthermia susceptible pig model

Anaesthetic techniques for malignant hyperthermia susceptible (MHS) patients should include drugs which do not trigger MH and provide stress free conditions. Thus all new drugs should be screened for their susceptibility to trigger MH. We have screened propofol, using the MHS pig model. In none of the animals exposed to propofol, were there signs of MH, even after challenge with suxamethonium. However, the same animals developed MH when exposed to halothane alone or with suxamethonium. Despite the problems of extrapolating from this study to man, it is unlikely that propofol may trigger an episode of MH.

[Interaction of nimodipine and isoflurane in surgery of intracranial aneurysm]

A moderate controlled hypotension has been performed with isoflurane in the presence of nimodipine (4 mg.h-1) on ten patients anesthetized for cerebral aneurysm clipping. The administration of both drugs induced a dose-dependent hypotension secondary to the reduction of the systemic vascular resistance without impairment of cardiac index. Nimodipine did not modify the cardiovascular effects of isoflurane. It is concluded that intravenous administration of nimodipine should be continued during the operative period.

[Central core disease associated with malignant hyperthermia sensitivity]

The authors report the case of a 57-year old woman who was susceptible to malignant hyperthermia (MH) and also had central core disease (CCD) of muscle. The latter was asymptomatic and was discovered when muscle biopsy was performed for in vitro tests of susceptibility to malignant hyperthermia. This case was compared with the 117 cases of CCD and 33 cases of CCD associated with MH published in the literature. Anaesthesia-induced MH is lethal in 80 per cent of the cases without treatment and in 20 per cent with treatment. CCD and MH are both transmitted as autosomal dominant traits. Susceptibility to MH is a functional abnormality of unknown mechanism. CCD is a disease of muscle fibre structure. One may hope that molecular studies and genetic probes will show whether or not these two diseases are transmitted by genes that are similar but distinct and independent.

[Screening tests for malignant hyperthermia susceptibility]

The ideal screening test for malignant hyperthermia susceptibility (MHS) has yet to be discovered. It should be simple noninvasive, yet totally specific and sensitive. Until such an ideal test becomes available, allowing simple routine preoperative screening, tests should only be used in certain specific situations. These include: patients in whom a clinical crisis was suspected; the members of the family of a subject labeled MHS because of a fatal, or otherwise, crisis, or in whom tests were positive; patients with other pathological conditions which could be linked to malignant hyperthermia (MH) (some myopathies, effort or stress MH, neuroleptic malignant syndrome). The various tests proposed in the literature aim at revealing MHN subjects, using or not a triggering agent, halothane most often. However, detecting these abnormalities sometimes gives greater insight into the physiopathology of MH than in the detection of an individual patient's susceptibility. The tests have been classified as in vivo, electrophysiological, blood, and in vitro muscle biochemical, morphological, and pharmacological tests. The discovery of new tests gives renewed hope: CPK levels, platelet tests, calcium sarcoplasmic reticular reuptake, lymphocyte Quin 2 test, nuclear magnetic resonance spectroscopy. However, experts worldwide agree that the only reference test to this day remains the in vitro halothane caffeine contracture tests. These tests have shown their reliability; they must be performed on muscle strips obtained from surgically removed muscle biopsies, by laboratories used to this technique and who have at their disposal a sufficiently large group of MHS subjects with a clear-cut clinical crisis, as well as controls. The patients must therefore travel to these laboratories. The design of common protocols for European laboratories on one hand, and the North American laboratories on the other, is a good guarantee of the reliability of these tests.

[Calcium inhibitors and anesthesia]

Calcium blockers (CB) are routinely used. This could lead to possible interference with anaesthetic drugs. CB prevent calcium from entering the cell by inhibiting the slow voltage-dependent calcium channels. They act mostly on heart and smooth muscle. Of all the possible indications, the three that are confirmed are coronary heart disease, arterial hypertension and supraventricular rhythm disturbances. Most of the work published and the cases reported concerns interactions between CB and halogenated anaesthetic agents; the latter's actions on the heart depend on cellular calcium exchange. Also, the cardiovascular effects of these anaesthetics are similar to that of CB. Experimentally, halothane and enflurane have direct cardiac inhibitory effects similar to verapamil and diltiazem, whereas isoflurane's properties seem closer to the dihydropyridines (nifedipine and nicardipine). Giving verapamil or diltiazem increases the number of sino-atrial and atrio-ventricular blocks when using a halogenated agent. Clinically, interpreting the effects of CB during anaesthetic induction is difficult because of the pathology (coronary heart disease, cardiac failure), the other drugs (beta-blockers and nitrates) and the type of anaesthesia (emergency or elective). Interactions can give rise to anything from a severe cardiovascular collapse, requiring catecholamines, to a mild fall in blood pressure which responds well to plasma expansion, or even no effect on blood pressure. Rebound is seen on stopping CB in patients with coronary heart disease or arterial hypertension; stopping them before surgery does not therefore seem justified. However, extreme care must be taken when using halogenated agents for patients under treatment with CB and/or beta-blockers. A wary anaesthetist will be able to adapt the technique to the patient. It has been suggested that CB could be used to treat preoperatively myocardial ischaemia (diltiazem), hypertensive crises (nifedipine, nicardipine) and ventricular rhythm disturbances (verapamil); this must be done with caution, the patient being closely monitored (haemodynamic and electrocardiographic monitoring). Postoperatively, intranasal nifedipine, continuous intravenous nicardipine or diltiazem have been used to treat increases in arterial blood pressure during recovery and to adapt the cardiovascular system to the increased metabolic needs. Here again, close patient monitoring is essential. In any case, treatment with CB which has been stopped should be started up again as soon as possible.

[Tests of contracture and sensitivity to malignant hyperthermia in 27 patients]

Twenty-seven patients, four of whom had presented with a crisis of malignant hyperthermia and the 23 other being close relatives of such patients, underwent a muscle biopsy so as to determine their susceptibility to malignant hyperthermia. Halothane-caffeine contracture tests, interpreted in accordance with the criteria of the European Group on Malignant Hyperthermia, yielded the following results: 13 positive (MHS), 10 negative (MHN), 4 equivocal (MHE). The history, clinical examination, CPK level, histoenzymatic morphology and electron microscopic study did not provide information sensitive enough to use for the detection of susceptibility to malignant hyperthermia. This confirmed the literature: the halothane-caffeine contracture test remains the only reliable diagnostic test to detect this susceptibility, despite the search for non invasive tests. If the mechanism of triggering a contracture to increasing doses of caffeine is well known in normal muscle, it is the smaller concentrations required which suggests malignant hyperthermia abnormality. The halothane effect is less well understood. A concentration less than or equal to 2 vol % yields a contracture only in MHS muscle. Differences in protocols used by American authors emphasize the importance of standardization as used by the European Group, which is the only way of collecting and comparing results on well over a thousand patients. This confrontation should reduce the number of equivocal diagnoses and allow a correct classification of patients at risk or their relatives as MHS or MHN.

[Registration of peranesthetic cases of malignant hyperthermia in France. An update]

Sixty-two suspected crises of anaesthetic malignant hyperthermia (MH) were collected between 1969 and 1988 by a retrospective inquiry which lasted four years. 33 patients (53%) died whilst 29 survived. 20 cases were confirmed to be MH, either directly or indirectly by way of muscle biopsy and halothane and caffeine contracture tests carried out according to the European MH group protocol by two laboratories. This group included 11 of the deaths, one family member of whom, at least, is sensitive (MHS), 7 MHS survivors and 2 survivors too young to undergo muscle biopsy but belonging to MHS families. 21 cases were highly suspect of MH: 15 of the deaths which occurred in a typical way, and 6 patients of three different families who have suffered from anaesthetic deaths which, clinically, suggested MH. Another 15 were possible MH cases, all survivors, including one case of Steinert's disease and a brother of a case of central core disease. 2 cases were still being debated, because they had equivocal results for the caffeine test (MHEc); the last 4 had negative muscle biopsies and were excluded. 33 close relatives of the MH patients were diagnosed as MHS. 44 others were found to be free from the genetic predisposition. It was strongly recommended to yet 11 others that they carry the MHS card because they were MHEc. The clinical, surgical and anesthetic pictures were always as described in the literature. The anaesthetic protocols included inhalational agents in 90% of cases; these were combined with suxamethonium in 55% of cases. Dantrolene was only used in 32% of cases, and then at inadequate doses and very often too late; this probably explains the large number of treatment failures. The number of severe forms of MH was also very high in this series (70%). The need to increase the means of prevention and screening for MH in France is stressed.

Neuroleptic malignant syndrome and malignant hyperthermia. In vitro comparison with halothane and caffeine contracture tests

The in vitro halothane and caffeine contracture tests have been performed on muscle tissue from six survivors of the neuroleptic malignant syndrome. The results, which are expressed in accordance with the criteria of the European MH Group, defined five of the subjects as MHN and one patient as MHE. It is concluded that there is no common pathophysiological link between the neuroleptic malignant syndrome and malignant hyperthermia.

[Anesthesia for arthroscopy of the knee: propofol versus thiopental and halothane]

Sixty ASA I or II patients, who underwent general anaesthesia for arthroscopy of the knee, were separated into two groups. Induction was performed either with thiopentone 7 mg . kg-1 (group I) or with propofol 2.5 mg . kg-1 (group II). All patients were intubated and ventilated. Dextromoramide was used as analgesic. Maintenance of anaesthesia was obtained with halothane inhalation (group I) or by continuous automatic injection of propofol at a dose of 9 mg . kg-1 . h-1 (group II). Induction and maintenance were satisfactory in both groups. Pulse rate was stable at induction and intubation for the propofol group, whereas it increased at both stages of anaesthesia with thiopentone; it fell moderately in both groups afterwards. Systolic and diastolic blood pressures dropped more in the propofol group after induction, with a maximum decrease of 20%. Recovery was significantly more rapid and comfortable with propofol than with thiopentone.

[Bronchial diffusion of ceftriaxone]

The value of a single daily injection of 2 g ceftriaxone in lower respiratory tract superinfections was demonstrated in 22 patients in a neurosurgical intensive care unit. Catheter bronchial samples were submitted to bacteriological investigation and ceftriaxone concentrations were determined in serum and bronchial secretions. Results show that sustained efficient levels of ceftriaxone were achieved and enabled the successful treatment of lower respiratory tract infections due to susceptible pathogens.

[Examination of the family of a patient susceptible to anesthetic malignant hyperthermia]

The familial nature of anaesthetic malignant hyperthermia must lead to the search for susceptibility in other members of the family of a sensitive subject. According to the literature, only in vitro studies of contraction characteristics of biopsied skeletal muscle fibres exposed to caffeine or halothane are of predictive value. Four members of the family of a patient who died as a result of malignant hyperthermia were investigated. The results expressed in accordance with the criteria defined by the European group on malignant hyperthermia, coupled with a histoenzymatic study, defined three of the subjects as HMN (negative) and one subject as HM (c) (equivocal or intermediate).

[Computerized records for obstetrical epidural analgesia]

An original recording and exploiting data programme has been built. It is in Basic language for Apple II. The data programme allows the care of obstetric peridural analgesic records. The medical interest is the record edition which is possible when the patient comes back. The scientific interest is statistics produced quickly from a great number of records. The record, record edition and statistical edition are described.

[Technics for artificial ventilation of a single lung during thoracotomy]

Different means of limiting the fall in arterial PO2 produced by single artificial ventilation were studied in 60 patients during thoracotomy. Changing from ventilating both lungs to the one healthy lung in the lateral recumbent position, without modifying tidal volume and frequency, brought about a fall in arterial PO2 from 180 +/- 56 to 67 +/- 40 mmHg. The alveolar to arterial oxygen gradient increased to 110 +/- 45 mmHg (the alveolar oxygen pressure being calculated). Reducing the tidal volume so as to keep the inflation pressure at its initial level did not improve the arterial PO2 but slightly increased the arterial PCO2 (2.3 mmHg). The use of 6 to 8 cm H2O positive end-expiratory pressure did not significantly modify the arterial PO2 or PCO2. Increasing the inspired oxygen fraction from 0.5 to 0.7 increased the arterial PO2 from 100 +/- 89 mmHg to 165 +/- 59 mmHg, whilst the alveolar to arterial oxygen gradient increased to 118 +/- 60 mmHg. Clamping the pulmonary artery increased the arterial PO2 and dual lung ventilation restored it to its initial value. Therefore, the only effective means of increasing oxygenation was to increase the inspired oxygen fraction. Unilateral continuous positive airway pressure was not used so as not to impair surgery. Dual lung ventilation may be necessary if the arterial PO2 remains low.

[Sodium nitroprusside and coronary surgery]

The anti-hypertensive properties of sodium nitroprusside have been tested in 20 patients undergoing coronary arterial surgery. Were measured the arterial pressure, heart rate, mean right atrial pressure and mean left atrial pressure. The cardiac output, systemic vascular resistance and left ventricular stroke work index were deduced. A dose of 0.8 to 3 micrograms . kg-1 . min-1 sodium nitroprusside was given at the start of surgery, and immediately afterwards. The results showed a decrease of the systemic vascular resistance, a significant drop of arterial pressure, and a significant increase of heart rate as well as a tendency for the cardiac output to fall, probably because of insufficient vascular filing. When the mean left atrial pressure was kept at 14.8 +/- 3 mmHg (1.97 +/- 0.40 kPa), and left ventricular stroke work index fell, whilst cardiac output increased. Sodium nitroprusside seemed to be useful in coronary arterial surgery if used with care.

[Anesthetic management for delivery of 38 cardiac patients (author's transl)]

The choice of anesthesia is discussed in connection with a serie of 38 women cardiac and pregnant cared from 1976 to 1979, 32 of them having delivered a child. Peridural analgesia improves the labour and the delivery without inconveniene for either mother of child, but general anesthesia must be prefered for cesarean section. Anticoagulant therapy is a contra-indication for peridural analgesia.