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International audience; Purpose: In patients with COPD, one of the leading indications for domiciliary non-invasive ventilation (NIV), a major paradigm shift has been observed over the past decade in the method for adjusting NIV settings, with the use of sufficient ventilatory support to achieve a significant reduction in PaCO2. Whether this approach may be relevant to other populations, especially slowly progressive neuromuscular diseases (NMD), is unknown.Methods: This study was conducted as a post hoc analysis from a previously published randomized controlled trial (NCT03458507). Patients with NMD treated with domiciliary NIV were stratified according to the level of ventilatory support: high-level tidal volume (HLVT; mL/kg of predicted body weight [PBW]) or high-level pressure support (HLPS), defined as a value above median value of the whole population (> 6.8 mL/kgPBW or 9.0 cmH2O, respectively). Primary outcome was mean nocturnal transcutaneous CO2 pressure (PtcCO2). Secondary outcomes included adherence to NIV, leaks, and side effects.Results: Of a total of 26 patients, 13 were exposed to HLVT, with significantly lower nocturnal PtcCO2 (respectively 40.5 ± 4.2 vs. 46.3 ± 3.9 mmHg, p = 0.002). A linear correlation between VT (mL/kgPBW) and mean nocturnal PtcCO2 was evidenced (r = - 0.59, 95%CI [- 0.80; - 0.25], p = 0.002). No significant impact of HLVT was found on secondary outcomes.Conclusion: Despite the lack of power of this post hoc analysis, our results suggest that higher levels of ventilatory support are correlated with lower PtcCO2 in patients with NMD. Further studies are desirable to assess the extent to which the level of assistance influences PaCO2 evolution in patients with slowly progressive NMD, as well as in restrictive thoracic disorders.

In subjects with neuromuscular diseases (NMD), the choice of facemask is essential for successful long-term noninvasive ventilation (NIV). While nasal masks usually represent the first line of treatment, almost a third of our subjects with NMD use an oro-nasal interface. Factors associated with the choice of mask remain poorly understood. We provide an original analysis of a previous prospective, multi-centric, Franco-Belgian survey investigating the factors associated with the type of nocturnal mask used in 116 adult NMD subjects treated with NIV. In these patients oro-nasal mask use was more often associated with non-Duchenne muscular dystrophy, older subjects, higher body mass index, better upper limb autonomy allowing independent mask removal and shorter periods of ventilation. Controlled prospective studies are needed to compare the efficacy and tolerance of different interfaces in this specific population.

For intra-operative neurophysiological monitoring during spine and spinal cord surgery, the challenge is to detect, in real-time, the occurrence of neurological impairment at onset in order to remedy the problem as quickly as possible before it becomes definitely acquired and irreversible. The past three decades were marked by considerable technical progress. Feasibility and reliability have now reached a very high level. A multimodal approach combining simultaneous monitoring of somatosensory and motor pathways has enabled a considerable decline in the rate of false negatives reported in the 80s when somatosensory evoked potentials (SSEP) were monitored alone. Several methods of monitoring are described in the literature. Combining transcranial electric stimulation of muscle motor evoked potentials (mMEP) and cortical SSEP allows non-invasive and selective monitoring of the posterior columns and pyramidal tract. One of the most widely used techniques internationally backed by a broad consensus within the International Society of Intra-operative Neurophysiology (ISIN), this technique remains exceptional in French-speaking countries. We expose here the methodological aspects for the readers of La Revue Neurologique.

Background The efficacy of enzyme replacement therapy (ERT) in patients at an advanced stage of Pompe disease has only been addressed in a few studies. Our objective was to assess the long term effects of ERT in a cohort of patients with severe Pompe disease. Methods We identified patients from the French Pompe Registry with severe respiratory failure and permanent wheelchair use (assisted walk for a few meters was allowed) when starting ERT. Patients' medical records were collected and reviewed and respiratory and motor functions, before ERT initiation and upon last evaluation were compared. Results Twelve patients (7 males) were identified. Median age at symptom onset was 24 years [IQR = 15.5; 36.0]. At baseline ventilation was invasive in 11 patients and noninvasive in one, with a median ventilation time of 24 h [IQR = 21.88; 24.00] (min 20; max 24). ERT was initiated at a median age of 52.5 years [IQR = 35.75; 66.50]. Median treatment duration was 55 months [IQR = 39.5; 81.0]. During observational period no adverse reaction to ERT was recorded, five patients (41.67%) died, three decreased their ventilation time by 30, 60 and 90 min and two increased their assisted walking distance, by 80 and 20 m. Conclusion Some patients at a very advanced stage of Pompe disease may show a mild benefit from ERT, in terms of increased time of autonomous ventilation and of enlarged distance in assisted walk. ERT can be initiated in these patients in order to retain their current level of independence and ability to perform daily life activities.

Resume Le role du Centre d'innovations technologiques (CIT) de l'hopital de Garches est de promouvoir la recherche et le developpement de nouveaux dispositifs medicaux et aides techniques dediees aux personnes handicapees et de suivre et evaluer les innovations dans ce domaine. Cela est effectue en cooperation avec les utilisateurs, chercheurs, industriels, et professionnels du domaine. Les industriels sont sollicites et soutenus pour developper des prototypes utilisant de nouvelles technologies pour aider les personnes handicapees. Le CIT evalue de nombreux types de produits allant de l'evaluation d'une prothese de cheville a celle de nouveaux types de fauteuils roulants. De nombreux projets ont abouti positivement et ont finalement contribue a l'amelioration des performances de dispositifs et aides techniques dans le domaine du handicap moteur.

Resume Introduction La ventilation non invasive (VNI) represente une technique d’assistance ventilatoire particulierement interessante en pediatrie. En effet, un nombre important de pathologies qui peuvent etre responsables d’une insuffisance respiratoire chronique dans l’enfance, comme les pathologies neuromusculaires, les anomalies des voies aeriennes, de la cage thoracique et/ou du poumon, ou les anomalies du controle ventilatoire, sont avant tout des pathologies qui se traduisent par une hypoventilation alveolaire qui peut etre amelioree par une assistance ventilatoire. Etat des connaissances Peu d’etudes physiologiques sur la VNI ont ete realisees chez l’enfant. Les modes ventilatoires et les reglages les plus appropries pour chaque pathologie n’ont pas ete clairement definis, et les criteres justifiant la mise en route de la VNI sont essentiellement bases sur des conferences de consensus qui concernent les pathologies neuromusculaires. Perspectives L’ensemble des intervenants prenant en charge ces enfants devraient combiner leurs efforts pour evaluer de maniere plus precise les effets physiologiques de la VNI a moyen et plus long terme sur les muscles respiratoires, la croissance du systeme respiratoire, l’activite inspiratoire, les criteres d’institution et surtout, le benefice en terme de developpement psycho-neurologique et qualite de vie. Conclusions Une meilleure evaluation des benefices physiologiques et psychologiques a moyen et plus long terme, associee a des progres techniques, concernant les ventilateurs et les interfaces, devrait favoriser l’essor de la VNI a domicile chez l’enfant.

For intra-operative neurophysiological monitoring during spine and spinal cord surgery, the challenge is to detect, in real-time, the occurrence of neurological impairment at onset in order to remedy the problem as quickly as possible before it becomes definitely acquired and irreversible. The past three decades were marked by considerable technical progress. Feasibility and reliability have now reached a very high level. A multimodal approach combining simultaneous monitoring of somatosensory and motor pathways has enabled a considerable decline in the rate of false negatives reported in the 80s when somatosensory evoked potentials (SSEP) were monitored alone. Several methods of monitoring are described in the literature. Combining transcranial electric stimulation of muscle motor evoked potentials (mMEP) and cortical SSEP allows non-invasive and selective monitoring of the posterior columns and pyramidal tract. One of the most widely used techniques internationally backed by a broad consensus within the International Society of Intra-operative Neurophysiology (ISIN), this technique remains exceptional in French-speaking countries. We expose here the methodological aspects for the readers of La Revue Neurologique.

This study was designed to determine whether nasal airflow resistance (Rn) which is nonlinear during tidal breathing, can be assessed by the forced oscillation (FO) technique. Rn values obtained by the FO technique and extrapolated to 0 Hz (Rn,FO) were compared to those assessed by posterior rhinomanometry at maximal tidal inspiratory flow (Rn,m), at a 0.5 L x s(-1) flow (Rn,F), and at a 1 hPa transnasal pressure (Rn,P). All Rn estimates were derived from the same inspiratory and expiratory nasal flow and transnasal pressure signals obtained during tidal nasal breathing whilst a forced flow was applied at the nose via a rigid nasal mask in 23 healthy volunteers, of whom 14 had additional measurements after vasoconstrictor treatment. In the basal state, no significant difference, and significant correlations (p

N. Terzi1,2, D. Orlikowski2,3, H. Prigent2,4, Pierre Denise6, H. Normand6 and F. Lofaso2,4,5 1INSERM, ERI27, Caen; Univ Caen, Caen; CHRU Caen Service de Reanimation Medicale, Caen 2Centre d’Investigation Clinique Innovations Technologiques, Hopital Raymond Poincare, AP-HP; Universite de Versailles-Saint Quentin en Yvelines, Garches 3Centre d’Investigation Clinique Innovations Technologiques 805, Service de Reanimation et Unite de Ventilation a Domicile, Hopital Raymond Poincare, AP-HP 4Services de Physiologie Explorations Fonctionnelles Hopital Raymond Poincare, AP-HP 5INSERM, U 955, Creteil 6INSERM, ERI27, Caen, Univ Caen; CHRU Caen Service d’Explorations Fonctionnelles, Caen France

Inflation of the leg compartments of pneumatic trousers increases thoracic blood volume. The resultant response in respiratory impedence was investigated in nine normal volunteers, and compared with the response to increasing doses of inhaled carbachol. Respiratory impedance was measured by the forced oscillation technique (4-32 Hz), and respiratory resistance at zero frequency (R0) was extrapolated from linear regression analysis of resistive impedance versus frequency. The mean increase in R0 was 31% after inhalation of 125 micrograms carbachol, and 21% after inflation of pneumatic trousers. The percentage changes in R0 following pneumatic trouser inflation highly correlated those induced by inhalation of 125 micrograms carbachol (r = 0.98) Our data demonstrate that, even in normal subjects, pneumatic trouser inflation causes an increase in respiratory resistance, which can be predicted by the response to a low dose of carbachol. These results support the assumption that cholinergic agents might not only be bronchoconstrictors but also vasodilators of the bronchial vessels. At a low dose, the vasodilating action of carbachol could be the major factor involved in the respiratory response.

In order to assess the quality of sleep in surgical patients the amount of self-rated postoperative insomnia and its predisposing factors, we conducted a three-fold questionnaire * survey in 176 consecutive patients undergoing elective orthopaedic, vascular or abdominal surgery. The first questionnaire was completed the day preceding surgery, the second at the day of discharge and the third two weeks later. This survey concerned the patient's general status, his usual sleep profile and factors which could interfere with sleep (hypnotics, pain, environmental factors) throughout the study period. It allowed quantification of these parameters and the assessment of their time-course. Perioperative insomnia appeared to be a long-lasting phenomenon which persisted after discharge. Factor analysis and multiple regression models showed that postoperative, self-rated insomnia was multifactorial and mainly explained by the amount of postoperative pain (p = 0.035).

When is the optimal time to perform polysomnography in patients with neuromuscular disease? Non-invasive ventilation (NIV) is recognised as an efficient therapeutic option in patients with chronic respiratory insufficiency due to neuromuscular disorders. However, the long standing clinical experience with NIV contrasts with the absence of validated criteria for initiating this treatment and the paucity of data on its long term physiological and psychometric effects. Several consensus conferences agree on the value of daytime hypercapnia and an acute exacerbation as criteria for starting NIV because they are characteristic signs of established ventilatory failure.1–3 However, these two classical criteria are preceded by a variable period of nocturnal hypoventilation during which treatable symptoms—such as frequent arousals, severe orthopnoea, daytime fatigue, and alterations in cognitive function—may cause deterioration in the quality of the patient’s daily life. The first problem is to decide when to perform polysomnography in a patient with only a few symptoms.4 Polysomnography should be undertaken without delay when the patient develops symptoms related to sleep disordered breathing, but patients with neuromuscular disorders tend to underestimate symptoms such as fatigue before using mechanical ventilation. Sleep disordered breathing is difficult to establish in children because of reliance on parents and other caregivers who have a different perception of the child’s disease. Lung function parameters are poor indicators of nocturnal hypoventilation and data are only available for patients with neuromuscular disorders. Indeed, forced expiratory volume in 1 second (FEV1) has been shown to be inversely correlated with daytime arterial carbon dioxide tension (Paco2) and base excess in patients with Duchenne muscular dystrophy.5 But the recommendation to perform …

The authors investigated whether the amplitude and latency of diaphragm compound muscle action potential helped predict respiratory failure in Guillain-Barré syndrome. Both variables were significantly but weakly correlated with vital capacity (VC) and were similar in unventilated (n = 60) and ventilated (n = 10) patients. In ventilated patients, motor loss severity, progression, and VC reduction were significantly greater, and bulbar dysfunction was more common. Predicting respiratory failure must rely on clinical features and VC.

Non-invasive positive pressure ventilation (NPPV) represents a particularly interesting technique of ventilatory support in paediatrics. Indeed, a significant number of pathologies that may be responsible for chronic respiratory insufficiency in childhood, such as neuromuscular diseases, obstruction of the upper airways, disorders of chest wall and/or the lungs, and disorders of ventilatory control may all lead to alveolar hypoventilation that can be improved by ventilatory support.Few physiological studies have been performed on NPPV in children. The most appropriate modes and settings for each pathology have not been clearly defined, and the criteria for commencing NPPV are based essentially on consensus guidelines for the management of neuromuscular disorders.All the health care professionals managing these children should combine their efforts to evaluate more precisely the medium and long-term physiological effects of NPPV on the respiratory muscles, the development of the respiratory system, inspiratory activity, the indications for starting treatment and, above all, the benefits in terms of psycho-neurological development and quality of life.A better evaluation of the medium and long-term physiological and psychological benefits together with technical improvements in ventilators and associated equipment should allow a rapid expansion in the use of domiciliary NPPV in children.

A complete description of haemodynamics and gas exchange before and after percutaneous coil embolization of multiple pulmonary arteriovenous malformations is reported in a 45 year old woman with hereditary haemorrhagic telangiectasis (HHT). Before treatment, whilst the patient complained of severe dyspnoea during daily activities, an intrapulmonary shunt of 31% was measured (inert gas elimination technique), together with a cardiac output (thermodilution technique) of 12.4 L.min-1, resulting in a resting arterial oxygen tension (PaO2) of 8.53 kPa. Effective occlusion of all visible pulmonary malformations resulted in a rapid and major improvement in exercise tolerance, whilst resting PaO2 remained almost unchanged. A second investigation performed 4 months after treatment revealed a persistent intrapulmonary shunt of 19%, a cardiac output of 7.35 L.min-1, and a resting PaO2 of 10.53 kPa. We conclude that major increases in cardiac output largely contribute to the maintenance of PaO2 in patients with multiple pulmonary arteriovenous malformations and intrapulmonary shunt. The benefit of coil embolization is due both to an improvement in arterial oxygenation and a normalization of cardiac output.

Chronic respiratory insufficiency in cystic fibrosis (CF) is characterised by an increase in respiratory load, which leads to alveolar hypoventilation with the preservation of respiratory muscle strength. Non-invasive mechanical ventilation (NIMV) is able to improve alveolar ventilation and thus gas exchange and allow the the respiratory muscles to rest in patients with cystic fibrosis with variable severity of lung disease. These effects state the superiority of NIMV compared to oxygen therapy in CF. Invasive, highly specialized monitoring is recommended for the evaluation of ventilatory modes and the performances of new ventilators. After a successful evaluation, the monitoring of patients starting NIMV can be performed with simple, non invasive parameters such as gas exchange, tidal volume, respiratory rate, minute ventilation and comfort. In the long term however, studies are warranted to assess the benefit of NIMV in terms of lung function, quality of sleep and most importantly, quality of life.

To determine whether adding actimetry to simplified polygraphy (respiratory-parameter monitoring without neurophysiologic variable recording) improves apnea-hypopnea index (AHI) evaluation as compared to simplified polygraphy alone.Comparison of AHI values obtained by all-night polysomnography and by simplified polygraphy with and without actimetry.A teaching-hospital sleep laboratory in Garches, France.20 adults with suspected obstructive sleep apnea syndrome (OSAS).Data were analyzed by two scorers working independently. AHI was calculated as the number of apneas and hypopneas per hour of sleep time (polysomnography: AHI-pg), per hour of time in bed (simplified polygraphy: AHI-tib), and per hour of actimetry-estimated total sleep time (AHI-act). AHI-pg showed that 12 patients had OSAS (AHI10), which was severe (AHIor =30) in eight. AHI-act was more closely correlated to AHI-pg (r=0.976) than was AHI-tib (r=0.940). According to the Bland and Altman method, AHI-tib underestimated the AHI in two patients and AHI-act overestimated the AHI in one patient. For the diagnosis of severe OSAS, sensitivity and negative predictive value were 50% and 75% with AHI-tib as compared to 88% and 92.5% with AHI-act.Actimetry, when added to simplified polygraphy, may assist in the diagnosis of OSAS.

Invasive mechanical ventilation through a tracheostomy (TMV) is widely used to improve the survival of patients with severe restrictive respiratory disease caused by progressive neuromuscular disorders. For the last 20 yrs, there has been intense interest in noninvasive intermittent positive-pressure ventilation (NIMV) as a means of avoiding tracheostomy in these patients 1. However, there is no evidence that NIMV is beneficial before the development of daytime hypercapnia, and NIMV may even be detrimental by causing a delay in seeking medical advice during acute exacerbations. In keeping with this possibility, a randomized study in which Raphael et al. 2 evaluated the effect of NIMV on patients with Duchenne's muscular dystrophy before the stage of daytime hypercapnia, found an unexpected higher risk of death in the group receiving NIMV. It can be argued that this study did not use appropriate inclusion criteria for selecting the subset of patients most likely to benefit from “preventive” NIMV. Another limitation of this …

To compare the efficacy and patient tolerance, compliance, and preference between auto-continuous positive airway pressure (CPAP) and constant CPAP.Single-blinded, crossover, cohort study of consecutive patients with obstructive sleep apnea syndrome, with two treatment periods of 2 months each.Twenty-five patients (22 men, 3 women) with sleep apnea syndrome confirmed by ambulatory polysomnography.After baseline polysomnography, patients underwent in-laboratory polysomnography for titration of constant CPAP. The order of treatment was randomly allocated, either auto-CPAP and then constant CPAP, or vice versa. The auto-CPAP pressure range was 6 to 16 cm H(2)O. At the end of each 2-month period, patients underwent a control ambulatory polysomnography and received a questionnaire on subjective well-being and device evaluation. Duration of use was checked through CPAP device monitoring.No differences were found in apnea/hypopnea index (constant CPAP, 9.7+/-1.9 events/h vs auto-CPAP, 10.6+/-9.3 events/h), awakening/arousal index (constant CPAP, 13.7 +/- 8.0 events/h vs auto-CPAP, 15.5 +/- 8.9 events/h), slow-wave sleep duration, nocturnal saturation, or complaint of daytime sleepiness. The mean pressure required was significantly lower during auto-CPAP than during constant CPAP (8.8+/-1.8 cm H(2)O vs. 9.7+/-2.6 cm H(2)O, respectively). Patient tolerance, compliance, and duration of use were similar with both treatments.Auto-CPAP is as effective as constant CPAP. A wide pressure range for auto-CPAP can be used in all patients, suggesting that, in the future, use of a broad pressure range in the auto-CPAP mode could obviate the need for the titration night.

A reduction in arterial PCO2 is an important cause of respiratory muscle inhibition during pressure support (PS). A nonchemical inhibition of respiratory activity during PS has also been demonstrated. This nonchemical inhibition of inspiratory activity is not observed with all modes of mechanical ventilation. In fact, the higher is the initial flow rate provided by the ventilator, the more efficient the nonchemical inhibition of respiratory activity. Currently, PS is the ventilatory support technique which provides the highest initial inspiratory flow. However, these new physiological findings should facilitate the development of more effective ventilatory support techniques.

This study was designed to determine whether nasal airflow resistance (Rn) which is nonlinear during tidal breathing, can be assessed by the forced oscillation (FO) technique. Rn values obtained by the FO technique and extrapolated to 0 Hz (Rn,FO) were compared to those assessed by posterior rhinomanometry at maximal tidal inspiratory flow (Rn,m), at a 0.5 L x s(-1) flow (Rn,F), and at a 1 hPa transnasal pressure (Rn,P). All Rn estimates were derived from the same inspiratory and expiratory nasal flow and transnasal pressure signals obtained during tidal nasal breathing whilst a forced flow was applied at the nose via a rigid nasal mask in 23 healthy volunteers, of whom 14 had additional measurements after vasoconstrictor treatment. In the basal state, no significant difference, and significant correlations (p0.0001) were found between Rn,FO and the other Rn estimates. Only the regression line of Rn,FO versus Rn,m was not significantly different from the identity line. After nasal decongestion, Rn,P became significantly higher than the other Rn estimates (p0.005). The regression line of Rn,FO versus Rn,m remained nonsignificantly different from the identity line. Similar results were observed regarding the percentage values of the different Rn estimates after decongestant treatment. This study shows that, despite its nonlinearity, Rn can be assessed by the FO technique, and that Rn,FO and Rn,m could be indifferently used as physiological indices of nasal patency. As the FO technique is more difficult to implement than the conventional rhinomanometry, its interest in rhinology appears not to be obvious.

In order to assess the quality of sleep in surgical patients the amount of self-rated postoperative insomnia and its predisposing factors, we conducted a three-fold questionnaire * survey in 176 consecutive patients undergoing elective orthopaedic, vascular or abdominal surgery. The first questionnaire was completed the day preceding surgery, the second at the day of discharge and the third two weeks later. This survey concerned the patient's general status, his usual sleep profile and factors which could interfere with sleep (hypnotics, pain, environmental factors) throughout the study period. It allowed quantification of these parameters and the assessment of their time-course. Perioperative insomnia appeared to be a long-lasting phenomenon which persisted after discharge. Factor analysis and multiple regression models showed that postoperative, self-rated insomnia was multifactorial and mainly explained by the amount of postoperative pain (p = 0.035).

Heart/lung transplantation offers a unique opportunity for studying the role of pulmonary innervation on control of breathing. In heart/lung transplant patients the pattern of breathing has been found to remain unaffected at rest and when asleep. In contrast, CO2 breathing studies have yield conflicting results. In heart/lung transplant recipients with normal pulmonary function, the hypercapnic ventilatory response was not different from that seen in control subjects, whereas heart/lung transplant recipients with moderate restriction had a profound depression in the ventilatory response to CO2. These results suggested that pulmonary vagal afferent fibers may have a facilitating effect on the hypercapnic ventilatory response in patients with restriction. This result is in opposition with data from airway anesthesia studies. In studies of the effects of exercise in transplant patients, control of breathing was affected in the same way as in normal subjects with anesthetized airways: transplant patients had an appropriate level of ventilation with a disproportionate increase in tidal volume. In normal subjects after suppression of inspiratory activity by mechanical hyperventilation, hypercapnia at which inspiratory activity muscle recruitment appeared was lower when arterial CO2 was raised by decreasing ventilator ventilation rather than by adding CO2 in the inspiratory line. This was not the case in double lung transplant subjects. These findings suggest that pulmonary afferent nerves have an inhibitory effect on inspiratory activity in humans. In conclusion, pulmonary afferent play a negligible role in the control of breathing of human at rest but are important in regulating the pattern of ventilation during stress conditions and large tidal volume conditions.

We investigated the contribution of pulmonary afferent nerve fibers to the control of inspiratory activity in awake humans. Eight double lung transplant outpatients and eight normal subjects were hyperventilated with a mechanical ventilator. Respiratory frequency was increased until no respiratory activity was detectable. Then, by either adding CO2 in the inspired gas or decreasing respiratory frequency, end-tidal PCO2 (PETCO2) was increased until inspiratory activity (i.e. change in inspiratory airway pressure peak and/or time profile) was detected. In normal subjects, PETCO2 threshold for inspiratory muscle recruitment was significantly lower when frequency was decreased than when CO2 was added (31.3 +/- 6.8 Torr vs. 38.2 +/- 8.1 Torr respectively, P0.005). This was not the case in the double lung transplant group (31.5 +/- 6.5 Torr vs. 32.9 +/- 5.8 Torr). These findings suggest that pulmonary afferent nerves have an inhibitory effect on inspiratory activity in humans.

Two out of nine patients in which inferior vena cava interruption was performed with a Gunther filter developed a recurrent pulmonary embolism. In both cases, the filter had moved down and the anchoring legs had perforated the wall of the vena cava. The source of the pulmonary embolism was a clotted basket filter. Anticoagulation was given for two weeks in one patient and six months in the other after insertion of the filter, but it had been stopped before the thrombotic event leading to the recurrent pulmonary embolism. The formation of the thrombi had probably been caused by the migration of the filter and the subsequent perforation, which may have been facilitated by the cessation of the anticoagulation.

The authors investigated whether the amplitude and latency of diaphragm compound muscle action potential helped predict respiratory failure in Guillain-Barre syndrome. Both variables were significantly but weakly correlated with vital capacity (VC) and were similar in unventilated (n = 60) and ventilated (n = 10) patients. In ventilated patients, motor loss severity, progression, and VC reduction were significantly greater, and bulbar dysfunction was more common. Predicting respiratory failure must rely on clinical features and VC.

Two cases of hypokalemia which was deep (1.1 mmol/l), symptomatic and protracted were observed during the early course of acute massive chloroquine intoxication. Biochemical data suggest that the mechanism of hypokalemia in such cases is intracellular transport.