Plasma exchange morbidity in Guillain-Barré syndrome: results from the French prospective, randomized, multicenter study. The French Cooperative Group

OBJECTIVES

To describe all adverse events occurring during plasma exchange sessions in adult patients with the Guillain-Barré syndrome. To analyze these events with regard to the technical modalities and biological changes induced by sessions, and to try to identify a population at high risk for adverse events.

DESIGN

Double-blind, randomized, prospective, multicenter trial.

SETTING

A total of 28 French and Swiss intensive care units.

PATIENTS

The study is based on 220 patients allocated either to plasma exchange (n = 109) or not (n = 111). This study focused on 105 patients who received at least one plasma exchange, with replacement fluid secondly allocated by randomization to albumin, or fresh frozen plasma. A total of 105 patients underwent 390 plasma exchanges. Fifty-five patients received albumin (208 sessions) as replacement fluid, and 50 patients received fresh frozen plasma (182 sessions).

INTERVENTIONS

Prospective monitoring of patients for each session including technical modalities, adverse effects, and biological parameters.

MEASUREMENTS AND MAIN RESULTS

A total of 253 adverse incidents were recorded. At least one adverse incident occurred in 39% of plasma exchange sessions among 80 (76%) patients. In 15 patients, plasma exchange treatment had to be discontinued because of severe intolerance (six patients, including three patients with severe bradycardias), intercurrent complications, mainly infections (four patients), and technical difficulties. One patient with pneumococcal septicemia and pneumonia died during the second plasma exchange session. Fresh frozen plasma was associated with more adverse incidents than albumin (135 vs. 118, p = .008). The occurrence of adverse events was also related to the preplasma exchange hemoglobin level assessed before the session (p = .04). Otherwise, the frequency of adverse effects did not depend on technical modalities (type of equipment, anticoagulation). Age, sex, previous history, neurologic severity, and the need for mechanical ventilation, as assessed on inclusion in the study, did not modify the risk of adverse effects. Finally, occurrence of bradycardia did not rely on initial neurologic severity.

CONCLUSIONS

These results confirm that fresh frozen plasma should be abandoned as replacement fluid in plasma exchanges of Guillain-Barré syndrome patients. They also underline the need for close monitoring of patients during sessions and, especially, the respect of treatment contraindications. Some adverse incidents could be attributed to the underlying disease rather than to the plasma exchange session.

[Methods of investigating orthostatic hypotension]

Orthostatic hypotension, which is common mainly in the elderly, is in many cases related to hypovolemia and/or vasodilators intake. However, when an impairment of the autonomic nervous system is suspected, orthostatic hypotension severity and mechanism may be investigated. The most common tests are the head upright tilt-test and the Valsalva manoeuvre. Both of them examine the baroreflex system as a whole, and become non invasive tests with the development of finger arterial blood pressure continuous measurement. Each part of the baroreflex system may be investigated separately. So, cardiac vagal responses to ocular compression, to carotid sinus massage, to respiratory change or to atropine infusion, may be tested. On the other hand, sympathetic efferent pathways may be stimulated in a variety of ways, such as isometric exercise, cutaneous cold, mental arithmetic, norepinephrine infusion, or tiltest. None of these tests should be applied systematically, but according to the clinical features.

Breathing disorders during sleep in myasthenia gravis

Twenty consecutive patients (16 women and 4 men), with a mean age of 40 years, who were diagnosed and treated for myasthenia gravis were enrolled in a prospective investigation aimed at determining the amount of respiratory disturbance occurring during sleep while they received treatment. Patients were clinically evaluated to determine body mass index, presence of upper airway anatomical abnormalities, level of functional capacity and activity scored from 1 to 5, and presence of sleep-related complaints. They underwent daytime pulmonary function tests, determination of maximal static inspiratory pressure, measurement of transdiaphragmatic pressure, and measurement of arterial blood gas levels. Polygraphic monitoring during sleep, evaluating respiration and oxygen saturation, was also performed. Results indicated that in the studied population, all subjects had evidence of daytime diaphragmatic weakness as demonstrated by transdiaphragmatic pressure measurements, independent of the degree of autonomy and functional capacity and activity level reached. Older patients with moderately increased body mass index, abnormal total lung capacity, and abnormal daytime blood gas concentrations were the primary candidates for development of diaphragmatic sleep apneas and hypopneas, and oxygen desaturation of less than 90% during sleep. However, these clear indicators were not found in all subjects with sleep-related disordered breathing. Rapid-eye-movement sleep was the time of highest breathing vulnerability during sleep. Sleep-related complaints may also help identify subjects at risk for abnormal breathing during sleep, even when daytime functional activity is judged normal.

Incidence and causes of carbon monoxide intoxication: results of an epidemiologic survey in a French department

The purpose of this study was to estimate the incidence, mortality, and causes of carbon monoxide intoxications in France. A survey was conducted in the department of the Hauts-de-Seine, which is representative of the French population. Data were collected through a headquarters that had direct contact with all department emergency organizations and to a technical laboratory. During the 3-y study, 735 cases that were related to 291 events were reported. Thirty-six patients died. The average incidence of carbon monoxide intoxications was 17.5 per 100,000 inhabitants. Poisoning was caused by fires in 36 events and by car exhausts in 12. For the remaining events, causes were determined as follows for 196: water heaters (57%), boiler (20.5%), coal stove (9%), brazier (4%), cooker (2%), heating device (1.5%), and miscellaneous (6%). The main mechanisms of intoxication were a defective device, poor ventilation, or poor evacuation of combustion gases. Carbon monoxide intoxication occurs frequently in France, and preventive actions are warranted.

[Guillain-Barré syndrome. Recent clinical and therapeutic aspects]

Guillain-Barré syndrome is an acute primary polyradiculoneuritis. A prototype of demyelinating disease, its essential characteristic is that it spontaneously evolves towards recovery from paralysis. Yet the vital and functional prognosis may be compromised in severe cases. Death and motor sequelae are particularly to be feared when the maximum deficit is severe and the maximum paralysis phase is prolonged. Cardiovascular vegetative disorders are also more frequent in these extended types. Symptomatic treatment rests on close supervision of the patients during the paralysis extension phase. Transferring the patient to an intensive care unit is mandatory as soon as disorders of deglutition and/or a significant decrease of vital capacity appear. Plasma exchange is the only treatment proven to be effective. It must be carried out early on in patients whose deficit is severe enough to interfere with walking and for whom this treatment is not contra-indicated. Fresh frozen plasma must not be used as replacement solution: it creates more incidents and complications than diluted albumin and has no additional beneficial effect on the course of the neurological disease.

Acute carbon monoxide intoxication and hyperbaric oxygen in pregnancy

Modalities of oxygen therapy for pregnant women intoxicated with carbon monoxide (CO) are ill defined. Hyperbaric oxygen (HBO) is presumed to be hazardous to the pregnancy. On the other hand CO entails anoxic injuries in the mother and fetus. We have entered 44 pregnant women who sustained an acute carbon monoxide poisoning at home, into a prospective study in order to assess HBO tolerance. They were treated within 5.3 +/- 3.7 h (range: 1-12) of the intoxication with a combination of 2 h of HBO at a pressure of 2 atmospheres absolute (ATA) and 4 h of normobaric oxygen, irrespective of the clinical severity of the intoxication and of the age of pregnancy. Six patients were lost to obstetric follow-up. Only 2 patients sustained a spontaneous abortion: 1 within 12 h and 1 within 15 days of the intoxication. Thirty-four women gave birth to normal newborns. Finally 1 elected to undergo abortion for reasons unrelated to the intoxication and 1 gave birth to a baby with Down's syndrome. There is no evidence that HBO was involved with either abortion of our study. We conclude that HBO may be carried out in pregnant women acutely intoxicated with carbon monoxide.

Trial of normobaric and hyperbaric oxygen for acute carbon monoxide intoxication

The value of hyperbaric oxygen in the treatment of acute carbon monoxide intoxication was assessed in 629 adults who had been poisoned at home in the 12 h before admission to hospital. In patients without initial impairment of consciousness (group A) the effect of 6 h of normobaric oxygen (NBO) (group A0, n = 170) was compared with that of 2 h of hyperbaric oxygen (HBO) at 2 atmospheres absolute (ATA) plus 4 h NBO (group A1, n = 173). At the 1 month follow-up 66% of A0 and 68% of A1 patients had recovered. In patients with initial impairment of consciousness the effect of one session of HBO (group B1, n = 145) was compared with that of two sessions (group B2, n = 141); all group B patients also received 4 h of NBO. At 1 month of follow-up 54% group B1 and 52% group B2 patients had recovered. The 7 patients left with neuropsychiatric sequelae (3 B1, 4 B2) and the 4 who died (2 B1, 2 B2) had all presented with coma. HBO was not useful in patients who did not lose consciousness during carbon monoxide intoxication, irrespective of their carboxyhaemoglobin level, nor were two sessions of HBO in patients who sustained only a brief loss of consciousness. The prognosis is poorest for those presenting with coma; the trial needs to be pursued in this group of patients until the power of the study is sufficient to demonstrate the value or otherwise of HBO.

A transient state model for analysing ventilatory status in a randomized clinical trial

We designed a randomized clinical trial to determine the efficacy of plasma exchange in Guillain-Barré syndrome, an acute neurological disease leading to paralysis in previously healthy subjects. Some patients require temporary mechanical ventilation during the course of the disease. Ventilatory status was analysed using a three-state model with a transient state defined by use of temporary mechanical ventilation, and the probability of being mechanically ventilated modelled as a function of time since randomization. The plot of this function reflects the effect of plasma exchange on ventilatory status showing that fewer plasma-exchanged patients than controls required ventilatory assistance and that the duration of assistance was shorter. Similar functions can be used in a more general framework when the response criterion includes a transient state.

[Long-term effects of plasma exchange in myasthenia. Results of a randomized study]

A randomized study was carried out in 14 myasthenia patients to compare the long-term effects of two therapeutic regimens. Group I patients received prednisone 1 mg/kg/24 h for one month, then in decreasing dosage; in case of failure at the end of the first month, cyclophosphamide 2 mg/kg/24 h was added to the prednisone treatment. Group II patients received the same treatment associated with 3 plasma exchanges over a 10-day period; these were continued, if required, at the rate of once a week. The minimum follow up was one year. The results (greater improvement in muscular strength and vital capacity) were better after one month in group I and thereafter similar in both groups. However, the mean daily dose of prednisone was higher in Group I. The number of exacerbations of myasthenia was greater in group II (11 versus 2 in group I over a 24-months period). The mean fall in anti-R Ach ab was about the same in both groups. This study confirms the rapid effectiveness of plasma exchanges and their value in severe myasthenia. The higher incidence of exacerbations in Group II was probably due to a rebound phenomenon and points to the need for combined immuno-suppressive treatment.

[A fortultousness association: Bartter's syndrome and chondrocalcinosis (author's transl)]

Two adults patients presenting Bartter's syndrome have been studied for 9 years in one case, 7 years in the other. Both were affected with chondrocalcinosis. This association does not seem to be coincididental but suggests a pathogenic link between Bartter's syndrome and chondrocalcinosis; the two patients presented hypomagnesemia which, inhibiting intrasynovial pyrophosphatase, induces calcium pyrophosphate crystals deposits on fibrocartilages. Otherwise, excessive daily urinary excretion of PG E2 and PG F2 alpha was found in both patients. Indomethacin (150 mg daily) decreased urinary excretion of PG to normal values in the two cases, Kalaemia was completely normalized in one case, partially in the other.

Membrane oxygenators for acute respiratory insufficiency. Clinical use in 11 patients

Extracorporeal circulation with a membrane oxygenator (ECMO) was used in 11 patients with acute respiratory insufficiency who did not respond to conventional treatment. By pass was veno-arterial in every case, seven times with femoral artery return, three times with axillary artery return, and once with both femoral and axillary return. Five patients died on ECMO. Six patients were taken off ECMO and two of them are long-term survivors. In nine cases ECMO allowed short-term control of respiratory failure. The respective roles of oxygen supply from ECMO and the haemodynamic changes incurred by its use are discussed. Although use of ECMO for long periods seems less hazardous now, present results are restricted by the lack of therapy for the underlying pulmonary lesions.

[Periodic familial paralysis with hypokalemia. Hemodynamic and metabolic studies: favourable effect of acetazolamide (author's transl)]

The same protocol was used three times to produce a paralytic episode in a typical case of periodic familial paralysis with hypokalemia. This consisted of an effort together with a perfusion of hypertonic glucose serum and insulin. The first test provoked an attach of hypokalemic tetraplegia. The second test, two months after treatment with 500 mg daily of acetazolamide, produced no reaction. In the third test, the metabolic acidosis caused by acetazolamide was reduced by the injection of sodium bicarbonate, and a stronger effect than in the first test was observed. This confirms the efficacy of acetazolamide as a preventive treatment for paralytic attacks; the most reasonable hypothesis being that it acts through the metabolic acidosis that it induces. Metabolic and hemodynamic studies were carried out during the provoked attacks. Cardiac output and oxygen consumption are increased, while pulmonary capillary pressure and periopheral resistance are reduced. Diastolic pressure is lower when measured by an arm-cuff but shows no change when direct readings are taken in the blood-vessels. These results suggest that there is an increase in cellular energy needs, or that the smooth muscle in the vessel walls is paralyzed. The two tetraplegic attacks in tests 1 and 3 were associated with a metabolic acidosis, which is explained by a simultaneous transfer, though in the opposite direction, of H+ and K+ ions; the intra-cellular pH, as measured by the D.M.O. technique, was acid when there was not an attack, and this increased during paralysis.