Electrophysiology to predict mechanical ventilation in Guillain-Barré syndrome

Prediction of mechanical ventilation in Guillain-Barré syndrome at admission: Construction of a nomogram and comparison with the EGRIS model

Background

Respiratory failure requiring mechanical ventilation (MV) is a common and severe complication of Guillain-Barré syndrome (GBS) with a reported incidence ranging from 20 % to 30 %. Thus, we aim to develop a nomogram to evaluate the risk of MV in patients with GBS at admission and tailor individualized care and treatment.

Methods

A total of 633 patients with GBS (434 in the training set, and 199 in the validation set) admitted to the First Hospital of Jilin University, Changchun, China from January 2010 to January 2021 were retrospectively enrolled. Subjects (n = 71) from the same institution from January 2021 to May 2022 were prospectively collected and allocated to the testing set. Multivariable logistic regression analysis was applied to build a predictive model incorporating the optimal features selected in the least absolute shrinkage and selection operator (LASSO) in the training set. The predictive model was validated using internal bootstrap resampling, an external validation set, and a prospective testing set, and the model's performance was assessed by using the concordance index (C-index), calibration curves, and decision curve analysis (DCA). Finally, we established a multivariable logistic model by using variables of the Erasmus GBS Respiratory Insufficiency Score (EGRIS) and did the same analysis to compare the performance of our predictive model with the EGRIS model.

Results

Variables in the final model selected by LASSO included time from onset to admission, facial and/or bulbar weakness, Medical Research Council sum score at admission, neutrophil-to-lymphocyte ratio, and platelet-lymphocyte ratio. The model presented as a nomogram displaying favorable discriminative ability with a C-index of 0.914 in the training set, 0.903 in the internal validation set, 0.953 in the external validation set, and 0.929 in the testing set. The model was well-calibrated and clinically useful as assessed by the calibration curve and DCA. As compared with the EGRIS model, our predictive model displayed satisfactory performance.

Conclusions

We constructed a nomogram for early prediction of the risk of MV in patients with GBS. This model had satisfactory performance and appeared more efficient than the EGRIS model in Chinese patients with GBS.

European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and treatment of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. Symptoms may vary greatly in presentation and severity. Besides weakness and sensory disturbances, patients may have cranial nerve involvement, respiratory insufficiency, autonomic dysfunction and pain. To develop an evidence-based guideline for the diagnosis and treatment of GBS, using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology a Task Force (TF) of the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) constructed 14 Population/Intervention/Comparison/Outcome questions (PICOs) covering diagnosis, treatment and prognosis of GBS, which guided the literature search. Data were extracted and summarised in GRADE Summaries of Findings (for treatment PICOs) or Evidence Tables (for diagnostic and prognostic PICOs). Statements were prepared according to GRADE Evidence-to-Decision (EtD) frameworks. For the six intervention PICOs, evidence-based recommendations are made. For other PICOs, good practice points (GPPs) are formulated. For diagnosis, the principal GPPs are: GBS is more likely if there is a history of recent diarrhoea or respiratory infection; CSF examination is valuable, particularly when the diagnosis is less certain; electrodiagnostic testing is advised to support the diagnosis; testing for anti-ganglioside antibodies is of limited clinical value in most patients with typical motor-sensory GBS, but anti-GQ1b antibody testing should be considered when Miller Fisher syndrome (MFS) is suspected; nodal-paranodal antibodies should be tested when autoimmune nodopathy is suspected; MRI or ultrasound imaging should be considered in atypical cases; and changing the diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP) should be considered if progression continues after 8 weeks from onset, which occurs in around 5% of patients initially diagnosed with GBS. For treatment, the TF recommends intravenous immunoglobulin (IVIg) 0.4 g/kg for 5 days, in patients within 2 weeks (GPP also within 2-4 weeks) after onset of weakness if unable to walk unaided, or a course of plasma exchange (PE) 12-15 L in four to five exchanges over 1-2 weeks, in patients within 4 weeks after onset of weakness if unable to walk unaided. The TF recommends against a second IVIg course in GBS patients with a poor prognosis; recommends against using oral corticosteroids, and weakly recommends against using IV corticosteroids; does not recommend PE followed immediately by IVIg; weakly recommends gabapentinoids, tricyclic antidepressants or carbamazepine for treatment of pain; does not recommend a specific treatment for fatigue. To estimate the prognosis of individual patients, the TF advises using the modified Erasmus GBS outcome score (mEGOS) to assess outcome, and the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess the risk of requiring artificial ventilation. Based on the PICOs, available literature and additional discussions, we provide flow charts to assist making clinical decisions on diagnosis, treatment and the need for intensive care unit admission.

European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and treatment of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. Symptoms may vary greatly in presentation and severity. Besides weakness and sensory disturbances, patients may have cranial nerve involvement, respiratory insufficiency, autonomic dysfunction and pain. To develop an evidence-based guideline for the diagnosis and treatment of GBS, using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, a Task Force (TF) of the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) constructed 14 Population/Intervention/Comparison/Outcome questions (PICOs) covering diagnosis, treatment and prognosis of GBS, which guided the literature search. Data were extracted and summarised in GRADE Summaries of Findings (for treatment PICOs) or Evidence Tables (for diagnostic and prognostic PICOs). Statements were prepared according to GRADE Evidence-to-Decision (EtD) frameworks. For the six intervention PICOs, evidence-based recommendations are made. For other PICOs, good practice points (GPPs) are formulated. For diagnosis, the principal GPPs are: GBS is more likely if there is a history of recent diarrhoea or respiratory infection; CSF examination is valuable, particularly when the diagnosis is less certain; electrodiagnostic testing is advised to support the diagnosis; testing for anti-ganglioside antibodies is of limited clinical value in most patients with typical motor-sensory GBS, but anti-GQ1b antibody testing should be considered when Miller Fisher syndrome (MFS) is suspected; nodal-paranodal antibodies should be tested when autoimmune nodopathy is suspected; MRI or ultrasound imaging should be considered in atypical cases; and changing the diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP) should be considered if progression continues after 8 weeks from onset, which occurs in around 5% of patients initially diagnosed with GBS. For treatment, the TF recommends intravenous immunoglobulin (IVIg) 0.4 g/kg for 5 days, in patients within 2 weeks (GPP also within 2-4 weeks) after onset of weakness if unable to walk unaided, or a course of plasma exchange (PE) 12-15 L in four to five exchanges over 1-2 weeks, in patients within 4 weeks after onset of weakness if unable to walk unaided. The TF recommends against a second IVIg course in GBS patients with a poor prognosis; recommends against using oral corticosteroids, and weakly recommends against using IV corticosteroids; does not recommend PE followed immediately by IVIg; weakly recommends gabapentinoids, tricyclic antidepressants or carbamazepine for treatment of pain; does not recommend a specific treatment for fatigue. To estimate the prognosis of individual patients, the TF advises using the modified Erasmus GBS outcome score (mEGOS) to assess outcome, and the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess the risk of requiring artificial ventilation. Based on the PICOs, available literature and additional discussions, we provide flow charts to assist making clinical decisions on diagnosis, treatment and the need for intensive care unit admission.

An Analysis of Respiratory Muscle Paralysis of Adult Patients in Guillain-Barré Syndrome: A Retrospective Analysis

Respiratory muscle paralysis is known as a very common complication of Guillain-Barré syndrome (GBS). However, most research has focused on its later stages rather than its earlier stages, including the prognosis of patients with this condition, or factors that act as early predictors of risk. Therefore, our study aimed to identify early predictors of respiratory muscle paralysis in patients with GBS and determine the short-term prognosis of such patients. We recruited 455 GBS patients (age ≥ 18) who had been hospitalized in the First Affiliated Hospital of Harbin Medical University between 2016 and 2021, retrospectively. We recorded clinical and laboratory data and used linear and logistic regression analysis to investigate the relationship between early clinical, examination results, and subsequent respiratory muscle paralysis. Among the 455 patients, 129 were assigned to a respiratory muscle paralysis group and 326 were assigned to a non-respiratory muscle paralysis group. Compared with the non-affected group, the time from onset to admission was shorter (p = 0.0003), and the Medical Research Council (MRC) score at admission and discharge was smaller in the affected group (p < 0.0001). Compared with the non-affected group, the affected group had higher Hughes and Erasmus GBS Respiratory Insufficiency Score (EGRIS) scores at admission and longer hospital stays (p < 0.0001). Patients in the affected group were more likely to have bulbar palsy and lung infections (p < 0.0001). To conclude, bulbar palsy, a higher EGRIS score and Hughes score at admission, a lower MRC score, and a shorter time between onset and admission, are all predictive risk factors for respiratory muscle paralysis in patients with GBS. An increase in any of these factors increases the risk of muscle paralysis. Patients with respiratory muscle paralysis have a poorer short-term prognosis than those without respiratory muscle paralysis. Therefore, we should attempt to identify patients with one or more of these characteristics in the early stages of admission, provide ventilation management, and administer IMV treatment if necessary.

Emerging biomarkers to predict clinical outcomes in Guillain-Barré syndrome

INTRODUCTION

Guillain-Barré syndrome (GBS) is an immune-mediated poly(radiculo)neuropathy with a variable clinical outcome. Identifying patients who are at risk of suffering from long-term disabilities is a great challenge. Biomarkers are useful to confirm diagnosis, monitor disease progression, and predict outcome.

AREAS COVERED

The authors provide an overview of the diagnostic and prognostic biomarkers for GBS, which are useful for establishing early treatment strategies and follow-up care plans.

EXPERT OPINION

Detecting patients at risk of developing a severe outcome may improve management of disease progression and limit potential complications. Several clinical factors are associated with poor prognosis: higher age, presence of diarrhea within 4 weeks of symptom onset, rapid and severe weakness progression, dysautonomia, decreased vital capacity and facial, bulbar, and neck weakness. Biological, neurophysiological and imaging measures of unfavorable outcome include multiple anti-ganglioside antibodies elevation, increased serum and CSF neurofilaments light (NfL) and heavy chain, decreased NfL CSF/serum ratio, hypoalbuminemia, nerve conduction study with early signs of demyelination or axonal loss and enlargement of nerve cross-sectional area on ultrasound. Depicting prognostic biomarkers aims at predicting short-term mortality and need for cardio-pulmonary support, long-term patient functional outcome, guiding treatment decisions and monitoring therapeutic responses in future clinical trials.

Risk Factors for Mechanical Ventilation in Patients with Guillain-Barré Syndrome

BACKGROUND

Respiratory support is required in 20-30% of patients with Guillain-Barré syndrome (GBS). We investigated clinical and biological risk factors for mechanical ventilation (MV) in northeast China through a retrospective GBS study. The Erasmus GBS Respiratory Insufficiency Score (EGRIS) is a prognostic model for MV in patients with GBS, and its usefulness has been validated in several countries but not in China. Therefore, we intended to validate the EGRIS model in our GBS cohort.

METHODS

A total of 252 patients with GBS were included in this study from January 2013 to October 2017. Risk factors for MV were identified via multivariate logistic regression analysis. The prognostic value of the EGRIS was validated via receiver operating characteristic curve analysis.

RESULTS

Thirty-one patients (12.3%) required MV (mean age 54.19 years), with a majority being male (77.4%). The risk factors for MV were male sex [odds ratio (OR) 3.720, 95% confidence interval (CI) 1.155-11.985, p < 0.05], shorter interval from onset to admission (OR 0.830, 95% CI 0.711-0.970, p < 0.05), lower Medical Research Council sum score at admission (OR 0.942, 95% CI 0.911-0.973, p < 0.001), neutrophil-to-lymphocyte ratio at admission (OR 1.174, 95% CI 1.049-1.315, p < 0.01), and cranial nerve deficit (OR 3.805, 95% CI 1.373-10.541, p < 0.05). The EGRIS had a good predictive ability for MV (area under the receiver operating curve 0.861) in patients with GBS, and a high EGRIS was a predictor for MV (OR 8.778, 95% CI 3.432-22.448, p < 0.001). However, there was no significant difference in ganglioside administration between ventilated and nonventilated patients.

CONCLUSIONS

An elevated neutrophil-to-lymphocyte ratio at admission and a high EGRIS could serve as predictors for MV in our GBS cohort.

International validation of the Erasmus GBS Respiratory Insufficiency Score

Objective

This study aimed to validate the Erasmus Guillain–Barré Syndrome Respiratory Insufficiency Score in the International Guillain–Barré Syndrome Outcome Study cohort, and to improve its performance and region‐specificity.

Methods

We examined data from the first 1,500 included patients, aged ≥6 years and not ventilated prior to study entry. Patients with a clinical variant or mild symptoms were also included. Outcome was mechanical ventilation within the first week from study entry. Model performance was assessed regarding the discriminative ability (area under the receiver operating characteristic curve) and the calibration (observed vs predicted probability of mechanical ventilation), in the full cohort and in Europe/North America and Asia separately. We recalibrated the model to improve its performance and region‐specificity.

Results

In the group of 1,023 eligible patients (Europe/North America n = 842, Asia n = 104, other n = 77), 104 (10%) required mechanical ventilation within the first week from study entry. Area under the curve values were ≥0.80 for all validation subgroups. Mean observed proportions of mechanical ventilation were lower than predicted risks: full cohort 10% versus 21%, Europe/North America 9% versus 21%, and Asia 17% versus 23%. After recalibration, predicted risks for the full cohort and Europe/North America corresponded to observed proportions.

Interpretation

This prospective, international cohort study validated the Erasmus Guillain–Barré Syndrome Respiratory Insufficiency Score, and showed that the model can be used in the full spectrum of Guillain–Barré syndrome patients. In addition, a more accurate, region‐specific version of the model was developed for patients from Europe/North America. ANN NEUROL 2022;91:521–531

Risk factors for mechanical ventilation in children with Guillain-Barré syndrome

BACKGROUND

We assessed clinical predictors of mechanical ventilation in children with Guillain-Barré syndrome (GBS) to help identify patients who require mechanical ventilation.

METHODS

We retrospectively collected the clinical, laboratory, and electrophysiological data of 103 children with GBS. Patients were categorized into two groups based on the requirement for mechanical ventilation. Variables that were significantly different between the two groups in univariate analysis were analyzed by multivariate logistic regression models.

RESULTS

Time from symptom onset to admission (P = .002), facial or bulbar weakness (P = .001), and axonal type (P = .005) were associated with mechanical ventilation in univariate analysis. In multivariate analysis, facial or bulbar weakness (odds ratio [OR], 7.936; P = .013) and axonal type (OR, 4.582; P = .022) were independent predictors for mechanical ventilation.

CONCLUSIONS

Facial or bulbar weakness and axonal type were associated with increased risk for mechanical ventilation in children with GBS.

[The prognosis and prognostic factor of Guillain-Barré Syndrome]

Guillain-Barré Syndrome (GBS) is an acute monophasic immune-mediated neuropathy, generally considered to be of good prognosis. However, 15-20% of GBS patients cannot walk independently at six months from onset. Poor prognostic factors for long-term functional disability included old age, preceding diarrhea, muscle weakness on admission and on day 7 from admission, severe GBS disability score at two weeks from admission and IgG antibody against GD1a/GD1b ganglioside complex. Factors related with requirement of mechanical ventilation included the time from onset to admission <7 days, muscle weakness on admission, facial and/or bulbar weakness and IgG antibody against GQ1b. Recently modified Erasmus GBS outcome score (mEGOS) and Erasmus GBS respiratory insufficiency score (EGRIS) were reported as prognostic factors for the long-term functional disability and respiratory insufficiency. Those were designed on Dutch patients. The usefulness of these tools in Japan or other countries remained unknown. The authors validated mEGOS and EGRIS on Japanese GBS patients in Japanese GBS outcome study, which revealed that these tools were also adaptable on Japanese GBS patients. To identify clinical and biological factors of GBS in more detail, such a large scale prospective study as International GBS outcome study (IGOS) is warranted.

Pulmonary Involvement in Patients with Guillain-Barré Syndrome in Subacute Phase

OBJECTIVES

To evaluate the pulmonary function in Guillain-Barre syndrome (GBS) patients in subacute phase and find clinical correlates of pulmonary dysfunction.

METHODS

This was a single-center, prospective, cross-sectional, hospital-based study in GBS patients performed in Department of Neurological Rehabilitation at a tertiary care institute. Clinical examination for pulmonary function was done by measuring chest expansion. The pulmonary function tests were carried out by Spirometry kit Microquark Cosmed, Italy. Fatigue was assessed by Fatigue Severity Scale, disability status by Hughes Disability Scale (HDS), and muscle weakness by Medical Research Council sum scores.

STATISTICAL ANALYSIS

Statistical analysis was performed by Stata 11. The significance of P value was adjudged against an alpha of 0.05.

RESULTS

Twenty-eight patients were included with 17 (61%) men and mean age of 31 years. Median duration of symptoms was 16.5 days. There were 10 (36%) demyelinating and 18 (64%) axonal variants. Twenty-six (93%) patients scored more than 2 on HDS. All study participants reported fatigue. Twenty-two (78.6%) patients had chest expansion of <2.5 cm. Spirometry showed restrictive pulmonary dysfunction in 23 (79%) patients. Significant correlation was found between abnormal pulmonary function test and chest expansion (P = 0.003).

CONCLUSION

Pulmonary dysfunction in GBS is common even during subacute phase. It needs to be identified and managed appropriately for better clinical outcome.

Predictors of respiratory failure in patients with Guillain-Barré syndrome: a systematic review and meta-analysis

OBJECTIVE

To systematically review the literature regarding the ability of clinical features to predict respiratory failure in patients with Guillain-Barré syndrome (GBS).

DATA SOURCES

We searched the PubMed and Ovid MEDLINE databases with the search terms "guillain barre syndrome" OR "acute inflammatory demyelinating polyneuropathy" OR "acute motor axonal neuropathy" OR "acute motor sensory axonal neuropathy" AND "respiratory failure" OR "mechanical ventilation". We excluded articles that did not report the results of original research (eg, review articles, letters), were case reports or series (ten or fewer patients), were not available in English, reported research in paediatric populations (16 years of age or younger), or were interventional studies. Article quality was assessed with the Newcastle-Ottawa quality assessment scale.

DATA SYNTHESIS

Thirty-four relevant studies were identified. Short time from symptom onset to hospital admission (less than 7 days), bulbar (odds ratio [OR], 9.0; 95% CI, 3.94-20.6; P < 0.001) or neck weakness (OR, 6.36; 95% CI, 2.32-17.5; P < 0.001), and severe muscle weakness at hospital admission were associated with increased risk of intubation. Facial weakness (OR, 3.74; 95% CI, 2.05-6.81; P < 0.001) and autonomic instability (OR, 6.40; 95% CI, 2.83-14.5; P < 0.001) were significantly more frequent in patients requiring intubation in our meta-analyses; however, the differences were not statistically significant in individual multivariable analysis studies. Four predictive models have been developed to assess the risk of respiratory failure for patients with GBS, each with good to excellent discriminative power (area under the receiver operating characteristic curve, 0.79-0.96).

CONCLUSIONS AND RELEVANCE

Early identification of GBS patients at risk of respiratory failure could reduce the rates of adverse outcomes associated with delayed intubation. Algorithms that predict a patient's risk of subsequent respiratory failure at hospital admission appear more reliable than individual clinical variables.

Risk factors for respiratory failure in Guillain-Barré syndrome in Bangladesh: a prospective study

Objective

We investigated clinical, biological, and electrophysiological risk factors for mechanical ventilation (MV) and patient outcomes in Bangladesh using one of the largest, prospective Guillain-Barré syndrome (GBS) cohorts in developing world.

Methods

A total of 693 GBS patients were included in two GBS studies conducted between 2006 and 2016 in Dhaka, Bangladesh. Associations between baseline characteristics and MV were tested using Fisher's exact test, χ² test, or Mann-Whitney U-test, as appropriate. Risk factors for MV were assessed using multivariate logistic regression. Survival analysis was performed using Kaplan-Meier method; comparisons between groups performed using log-rank test.

Results

Of 693 patients, 155 (23%) required MV (median age, 26 years; interquartile range [IQR] 17-40). Among the ventilated patients, males were predominant (68%) than females. The most significant risk factor for MV was bulbar involvement (adjusted odds ratio [AOR]:19.07; 95% CI = 89.00-192.57, P = 0.012). Other independently associated factors included dysautonomia (AOR:4.88; 95% CI = 1.49-15.98, P = 0.009) and severe muscle weakness at study entry (AOR:6.12; 95% CI = 0.64-58.57, P = 0.048). At 6 months after disease onset, 20% of ventilated and 52% of non-ventilated patients (P < 0.001) had recovered completely or with minor symptoms. Mortality rate was significantly higher among ventilated patients than non-ventilated patients (41% vs. 7%, P < 0.001).

Interpretation

Bulbar involvement, dysautonomia and severe muscle weakness were identified as the most important risk factors for MV among GBS patients from Bangladesh. The findings may help to develop predictive models for MV in GBS in developing countries to identify impending respiratory failure and proper clinical management of GBS patients.

Intubation, tracheostomy, and decannulation in patients with Guillain-Barré-syndrome-does dysphagia matter?

INTRODUCTION

Although patients with Guillain-Barré syndrome frequently require orotracheal intubation and tracheostomy, the incidence and relevance of neurogenic dysphagia prior to intubation and risk factors for prolonged requirement for a tracheal cannula have not yet been identified.

METHODS

Retrospective analysis of the medical records of 88 patients was performed. Clinical characteristics were compared between intubated and nonintubated patients and between immediately decannulated and not immediately decannulated patients.

RESULTS

Thirty-five (39.7%) patients required tracheostomy. Neuromuscular weakness and related respiratory insufficiency were the main reasons for intubation. In the subgroup of tracheotomized patients, immediate decannulation after completed respiratory weaning was possible in 14 (40%) patients. The severity of dysphagia, in particular pharyngolaryngeal hypesthesia, was related to the length of cannulation.

DISCUSSION

Respiratory muscle weakness is the main reason for intubation, whereas neurogenic dysphagia is the main risk factor for persisting cannulation. Dysphagia after weaning is most frequently characterized by severe laryngeal sensory deficit. Muscle Nerve 59:194-200, 2019.

Respiratory Muscle Assessment in Acute Guillain-Barré Syndrome

PURPOSE

Guillain-Barré Syndrome (GBS) is a life-threatening disease due to respiratory muscle involvement. This study aimed at objectively assessing the course of respiratory muscle function in GBS subjects within the first week of admission to an intensive care unit.

METHODS

Medical Research Council Sum Score (MRC-SS), vigorimetry, spirometry, and respiratory muscle function tests (inspiratory/expiratory muscle strength: PImax/PEmax, sniff nasal pressure: SnPna) were assessed twice daily. GBS Disability Score (GBS-DS) was assessed once daily. On days one (d1) and seven (d7), blood gases and twitch mouth pressure during magnetic phrenic nerve stimulation (Pmo,tw) were additionally evaluated.

RESULTS

Nine subjects were included. MRC-SS, vigorimetry, PImax, and SnPna increased between d1 and d7. GBS-DS, spirometry and Pmo,tw remained unaltered. Only SnPna correlated closely with the MRC-SS on both d1 (r = 0.77, p = 0.02) and d7 (r = 0.74, p = 0.02).

CONCLUSION

SnPna was the only parameter that correlated with MRC-SS, while the current gold standard of spirometry measurement did not.

Identification of prolonged phrenic nerve conduction time in the ICU: magnetic versus electrical stimulation

PURPOSE

Retrospective study of prospectively collected data to assess the reliability of cervical magnetic stimulation (CMS) to detect prolonged phrenic nerve (PN) conduction time at the bedside. Because PN injuries may cause diaphragm dysfunction, their diagnosis is relevant in intensive care units (ICU). This is achieved by studying latency and amplitude of diaphragm response to PN stimulation. Electrical stimulation (ES) is the gold standard, but it is difficult to perform in the ICU. CMS is an easy noninvasive tool to assess PN integrity, but co-activates muscles that could contaminate surface chest electromyographic recordings.

METHODS

In a first set of 56 ICU patients with suspected PN injury, presence and latency of compound motor action potentials elicited by CMS and ES were compared. With ES as the reference method, CMS was evaluated as a test designed to indicate presence or absence of PN injury. In eight additional patients, intramuscular diaphragm recordings were compared with surface diaphragm recordings and with the electromyograms of possible contamination sources.

RESULTS

The sensitivity of CMS to diagnose abnormal PN conduction was 0.91, and specificity was 0.84, whereas positive and negative predictive values were 0.81 and 0.92, respectively. Passing-Bablok regression analysis suggested no differences between the two measures. The correlation between PN latency in response to CMS and ES was significant. The "diaphragm surface" and "needle" latencies were close, and were significantly different from those of possibly contaminating muscles. One hemidiaphragm showed likely signal contamination.

CONCLUSION

CMS provides an easy reliable tool to detect prolonged PN conduction time in the ICU.

Comparison of intravenous immunoglobulin and plasma exchange in treatment of mechanically ventilated children with Guillain Barré syndrome: a randomized study

Introduction

Respiratory failure is a life threatening complication of Guillain Barré syndrome (GBS). There is no consensus on the specific treatment for this subset of children with GBS.

Methods

This was a prospective randomized study to compare the outcome of intravenous immunoglobulin (IVIG) and plasma exchange (PE) treatment in children with GBS requiring mechanical ventilation. Forty-one children with GBS requiring endotracheal mechanical ventilation (MV) within 14 days from disease onset were included. The ages of the children ranged from 49 to 143 months.

Randomly, 20 children received a five-day course of IVIG (0.4 g/kg/day) and 21 children received a five-day course of one volume PE daily. Lumbar puncture (LP) was performed in 36 patients (18 in each group).

Results

Both groups had comparable age (p = 0.764), weight (p = 0.764), duration of illness prior to MV (p = 0.854), preceding diarrhea (p = 0.751), cranial nerve involvement (p = 0.756), muscle power using Medical Research Council (MRC) sum score (p = 0.266) and cerebrospinal fluid (CSF) protein (p = 0.606).

Children in the PE group had a shorter period of MV (median 11 days, IQR 11.0 to 13.0) compared to IVIG group (median 13 days, IQR 11.3 to 14.5) with p = 0.037.

Those in the PE group had a tendency for a shorter Pediatric Intensive Care Unit (PICU) stay (p = 0.094).

A total of 20/21 (95.2%) and 18/20 (90%) children in the PE and IVIG groups respectively could walk unaided within four weeks after PICU discharge (p = 0.606).

There was a negative correlation between CSF protein and duration of mechanical ventilation in the PE group (p = 0.037), but not in the IVIG group (p = 0.132).

Conclusions

In children with GBS requiring MV, PE is superior to IVIG regarding the duration of MV but not PICU stay or the short term neurological outcome.

The negative correlation between CSF protein values and duration of MV in PE group requires further evaluation of its clinical usefulness.

Trial Registration

Clinicaltrials.gov Identifier NCT01306578

Guillain-Barré syndrome and influenza virus infection

BACKGROUND

In Western countries, the cause of 60% of all Guillain-Barré syndrome (GBS) cases remains unidentified. The number of cases of unidentified cause peaks in winter, and these cases are commonly preceded by respiratory tract infection or influenza-like illness. We investigated the triggering role of influenza virus infection.

METHODS

Of 405 patients with GBS who were admitted to a French reference center during 1996-2004, 234 had cases caused by an unidentified agent. We used time-series methods to study the correlation between the monthly incidence of such cases and influenza-like illnesses reported by the Sentinelles surveillance network. We analyzed anti-influenza antibodies using complement fixation testing and hemagglutination-inhibition assays. We studied etiological subgroups using Wilcoxon and Fisher's exact tests.

RESULTS

We found a positive association between the monthly incidence of GBS caused by an unidentified agent and reported influenza-like illnesses. Of 73 patients whose cases occurred during periods in which there was a possible link to influenza, 10 (13.7%) had serological evidence of recent influenza A, and 4 (5.5%) had serological evidence of influenza B. Eight of 10 influenza A-related cases occurred during "major" influenza seasons, and antibodies specific to the current epidemic strain were found in 9 cases. Most patients with influenza A-related cases were aged < 65 years, and none had antiganglioside antibodies. Influenza-related cases differed both from Campylobacter jejuni-related cases, with regard to the lack of need for mechanical ventilation (P = .014), and from the cases caused by an unidentified agent, with regard to the presence of preceding influenza-like illness or respiratory tract infection (P = .015) and longer time from the infectious event to GBS onset (P = .04).

CONCLUSIONS

Influenza viruses are infrequent triggering agents of GBS but may play a significant role during major influenza outbreaks. Influenza-related GBS displays specific features and is not associated with antiganglioside antibody response, which suggests the presence of underlying immune mechanisms.

Phrenic nerve conduction in the early stage of Guillain-Barre syndrome might predict the respiratory failure

OBJECTIVE

To investigate whether phrenic nerve conduction in the early phase of Guillain- Barre syndrome (GBS) predicts the need for respiratory assistance during the subsequent clinical course.

MATERIAL AND METHODS

We performed electrophysiological examinations of conventional peripheral nerve conduction and phrenic nerve conduction for GBS patients within 14 days from the onset. We excluded patients who had already been treated with immuno-related therapy and respiratory assistance.

RESULTS

Fifteen patients were enrolled. Three patients with the sum of phrenic nerve latency longer than 30 ms and the sum of bilateral diaphragmatic compound muscle action potential amplitude smaller than 0.3 mV required respiratory assistance after the conduction test.

CONCLUSION

Our findings showed that not only delayed distal latency but also decreased amplitude may predict the need for respiratory assistance during the subsequent disease course.

Clinical and electrophysiological predictors of respiratory failure in Guillain-Barré syndrome: a prospective study

BACKGROUND

Respiratory failure is the most serious short-term complication of Guillain-Barré syndrome and can require invasive mechanical ventilation in 20-30% of patients. We sought to identify clinical and electrophysiological predictors of respiratory failure in the disease.

METHODS

We prospectively assessed electrophysiological data and clinical factors, including identified predictors of delay between disease onset and admission, inability to lift head, and vital capacity, in patients admitted with Guillain-Barré syndrome. We related these factors to subsequent need for ventilatory support. Neurophysiological findings were classified as demyelinating, axonal, equivocal, unexcitable, or normal. Predictive values of clinical and electrophysiological data were tested using classification trees to build up a predictive model. This model was initially built up in a two-third (fitting set) then validated in a one-third (validation set) of the total sample. The fitting and validation sets were randomly selected. We also assessed the predictive value of this model for disability at 6 months.

FINDINGS

From 1998, to 2006, 154 patients with Guillain-Barré syndrome were included in the study and 34 (22%) were subsequently ventilated. Demyelinating Guillain-Barré syndrome was more common in patients who went on to be ventilated than in those who were not (85%vs 51%, p=0.0003). Vital capacity and the proximal/distal compound muscular amplitude potential (p/dCMAP) ratio of the common peroneal nerve were retained in the tree model, with a probability of needing ventilation of less than 2.5% in patients with a ratio of greater than 55.6% and a vital capacity more than 81% of predicted. A p/dCMAP ratio of the peroneal nerve less than 55.6% and age older than 40 years were retained as independent predictors of disability at 6 months.

INTERPRETATION

Neurophysiological testing is helpful for assessing risk of respiratory failure, which is highest in patients with evidence of demyelination and very low in those without both 55.6% conduction block of the common peroneal nerve and a 20% reduction in vital capacity.

EMG and duration of ventilatory support in children with Guillain-Barre syndrome

RATIONALE

Predicting length of stay in the intensive care unit (ICU) in children with Guillain-Barre syndrome may help decision-making at admission.

MATERIALS AND METHODS

Between 1996 and 2003, we attended to 30 children with Guillain-Barre syndrome who required ventilatory support in ICU. We prospectively collected different variables that could potentially predict prolonged length of stay and ventilatory support in ICU.

CONCLUSION

Using Cox proportional hazard analysis we found that lack of electrical excitability was the best predictor.

Improved serological diagnosis stresses the major role of Campylobacter jejuni in triggering Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is a postinfectious autoimmune polyradiculoneuropathy. The most frequent antecedent pathogen is Campylobacter jejuni, followed by cytomegalovirus. However, more than 40% of GBS cases currently cannot be attributed to triggering events. This might be due to the shortcomings of the serological assays used for diagnosing infections, in particular for C. jejuni. In our study investigating 36 patients with acute GBS, standard serological methods identified the triggering viral or bacterial etiology in only 25% of cases. However, using a highly specific enzyme-linked immunosorbent assay based on two recombinant outer antigens encoded by C. jejuni genes Cj0017 (P39) and Cj0113 (P18), we found serological evidence of a preceding C. jejuni infection in 80.6% of the patients but in only 3.5% of the controls. We conclude that the role of C. jejuni in triggering GBS has been greatly underestimated.

Airway management in neurological emergencies

Several neurological conditions may present to the emergency department (ED) with airway compromise or respiratory failure. The severity of respiratory involvement in these patients may not always be obvious. Proper pulmonary management can significantly reduce the respiratory complications associated with the morbidity and mortality of these patients. Rapid sequence intubation (RSI) is the method of choice for definitive airway management in the ED and is used for the majority of intubations. The unique clinical circumstances of each patient dictates which pharmacological agents can be used for RSI. Several precautions must be taken when using these drugs to minimize potentially fatal complications. Noninvasive positive pressure ventilation may obviate the need for intubation in a select population of patients. This article reviews airway management, with a particular emphasis on the use of RSI for common neurological problems presenting to the ED.