The Role of Non-invasive Ventilation and Factors Predicting Extubation Outcome in Myasthenic Crisis

[Non-invasive Mechanical Ventilation in Acute Respiratory Failure. Clinical Practice Guidelines - on behalf of the German Society of Pneumology and Ventilatory Medicine]

The guideline update outlines the advantages as well as the limitations of NIV in the treatment of acute respiratory failure in daily clinical practice and in different indications.Non-invasive ventilation (NIV) has a high value in therapy of hypercapnic acute respiratory failure, as it significantly reduces the length of ICU stay and hospitalization as well as mortality.Patients with cardiopulmonary edema and acute respiratory failure should be treated with continuous positive airway pressure (CPAP) and oxygen in addition to necessary cardiological interventions. This should be done already prehospital and in the emergency department.In case of other forms of acute hypoxaemic respiratory failure with only mild or moderately disturbed gas exchange (PaO2/FiO2 > 150 mmHg) there is no significant advantage or disadvantage compared to high flow nasal oxygen (HFNO). In severe forms of ARDS NIV is associated with high rates of treatment failure and mortality, especially in cases with NIV-failure and delayed intubation.NIV should be used for preoxygenation before intubation. In patients at risk, NIV is recommended to reduce extubation failure. In the weaning process from invasive ventilation NIV essentially reduces the risk of reintubation in hypercapnic patients. NIV is regarded useful within palliative care for reduction of dyspnea and improving quality of life, but here in concurrence to HFNO, which is regarded as more comfortable. Meanwhile NIV is also recommended in prehospital setting, especially in hypercapnic respiratory failure and pulmonary edema.With appropriate monitoring in an intensive care unit NIV can also be successfully applied in pediatric patients with acute respiratory insufficiency.

Weaning and extubation failure in myasthenic crisis: a multicenter analysis

Myasthenic crisis (MC) requiring mechanical ventilation is a serious complication of myasthenia gravis (MG). Here we analyze the frequency and risk factors of weaning- and extubation failure as well as its impact on the clinical course in a large cohort. We performed a retrospective chart review on patients treated for MC in 12 German neurological departments between 2006 and 2015. Weaning failure (WF) was defined as negative spontaneous breathing trial, primary tracheostomy, or extubation failure (EF) (reintubation or death). WF occurred in 138 episodes (64.2%). Older Age (p = 0.039), multiple comorbidities (≥ 3) (p = 0.007, OR = 4.04), late-onset MG (p = 0.004, OR = 2.84), complications like atelectasis (p = 0.008, OR = 3.40), pneumonia (p < 0.0001, OR = 3.45), cardio-pulmonary resuscitation (p = 0.005, OR = 5.00) and sepsis (p = 0.02, OR = 2.57) were associated with WF. WF occurred often in patients treated with intravenous immungloblins (IVIG) (p = 0.002, OR = 2.53), whereas WF was less often under first-line therapy with plasma exchange or immunoadsorption (p = 0.07, OR = 0.57). EF was observed in 58 of 135 episodes (43.0%) after first extubation attempt and was related with prolonged mechanical ventilation, intensive care unit stay and hospital stay (p ≤ 0.0001 for all). Extubation success was most likely in a time window for extubation between day 7 and 12 after intubation (p = 0.06, OR = 2.12). We conclude that WF and EF occur very often in MC and are associated with poor outcome. Older age, multiple comorbidities and development of cardiac and pulmonary complications are associated with a higher risk of WF and EF. Our data suggest that WF occurs less frequently under first-line plasma exchange/immunoadsorption compared with first-line use of IVIG.

Management of respiratory failure in immune checkpoint inhibitors-induced overlap syndrome: a case series and review of the literature

BACKGROUND

Checkpoint inhibitor-induced overlap syndrome ([OS] myocarditis, and myositis with or without myasthenia gravis) is rare but life-threatening.

CASES PRESENTATION

Here we present a case series of four cancer patients that developed OS. High troponinemia raised the concern for myocarditis in all the cases. However, the predominant clinical feature differed among the cases. Two patients showed marked myocarditis with a shorter hospital stay. The other two patients had a prolonged ICU stay due to severe neuromuscular involvement secondary to myositis and myasthenia gravis. Treatment was based on steroids, plasmapheresis, intravenous immunoglobulin, and immunosuppressive biological agents.

CONCLUSION

The management of respiratory failure is challenging, particularly in those patients with predominant MG. Along with intensive clinical monitoring, bedside respiratory mechanics can guide the decision-making process of selecting a respiratory support method, the timing of elective intubation and extubation.

Utility of Initial Arterial Blood Gas in Neuromuscular versus Non-Neuromuscular Acute Respiratory Failure in Intensive Care Unit Patients

Background: The arterial blood gas (ABG) parameters of patients admitted to intensive care units (ICUs) with acute neuromuscular respiratory failure (NMRF) and non-NMRF have not been defined or compared in the literature. Methods: We retrospectively collected the initial ABG parameters (pH, PaCO2, PaO2, and HCO3) of patients admitted to ICUs with acute respiratory failure. We compared ABG parameter ranges and the prevalence of abnormalities in NMRF versus non-NMRF and its categories, including primary pulmonary disease (PPD) (chronic obstructive pulmonary disease, asthma, and bronchiectasis), pneumonia, and pulmonary edema. Results: We included 287 patients (NMRF, n = 69; non-NMRF, n = 218). The difference between NMRF and non-NMRF included the median (interquartile range (IQR)) of pH (7.39 (7.32−7.43), 7.33 (7.22−7.39), p < 0.001), PaO2 (86.9 (71.4−123), 79.6 (64.6−99.1) mmHg, p = 0.02), and HCO3 (24.85 (22.9−27.8), 23.4 (19.4−26.8) mmol/L, p = 0.006). We found differences in the median of PaCO2 in NMRF (41.5 mmHg) versus PPD (63.3 mmHg), PaO2 in NMRF (86.9 mmHg) versus pneumonia (74.3 mmHg), and HCO3 in NMRF (24.8 mmol/L) versus pulmonary edema (20.9 mmol/L) (all p < 0.01). NMRF compared to non-NMRF patients had a lower frequency of hypercarbia (24.6% versus 39.9%) and hypoxia (33.8% versus 50.5%) (all p < 0.05). NMRF compared to PPD patients had lower frequency of combined hypoxia and hypercarbia (13.2% versus 37.8%) but more frequently isolated high bicarbonate (33.8% versus 8.9%) (all p < 0.001). Conclusions: The ranges of ABG changes in NMRF patients differed from those of non-NMRF patients, with a greater reduction in PaO2 in non-NMRF than in NMRF patients. Combined hypoxemia and hypercarbia were most frequent in PPD patients, whereas isolated high bicarbonate was most frequent in NMRF patients.

Weakness in the intensive care unit

When asked to assess patients in an intensive care unit (ICU) who have respiratory muscle weakness, oropharyngeal weakness and a vulnerable airway, our immediate thought may be of Guillain-Barré syndrome or myasthenia gravis, but there are many other possible causes. For example, previously unrecognised chronic neurological conditions may decompensate and require ICU admission. Clinicians can use various clinical clues to help recognise them and need to understand how patterns of weakness reflect differing causes of reduced consciousness on ICU. Additionally, patients admitted to ICU for any reason may develop weakness during their stay, the most likely cause being ICU-acquired weakness. Assessing patients in ICU is challenging, hampered by physical barriers (machines, tubes), medication barriers (sedatives) and cognitive barriers (delirium, difficulty communicating). Nonetheless, we need to reach a clinical diagnosis, organise appropriate tests and communicate clearly with both patients and ICU colleagues.

Motor neuron, peripheral nerve, and neuromuscular junction disorders

In amyotrophic lateral sclerosis (ALS), Guillain-Barré syndrome (GBS), and neuromuscular junction disorders, three mechanisms may lead, singly or together, to respiratory emergencies and increase the disease burden and mortality: (i) reduced strength of diaphragm and accessory muscles; (ii) oropharyngeal dysfunction with possible aspiration of saliva/bronchial secretions/drink/food; and (iii) inefficient cough due to weakness of abdominal muscles. Breathing deficits may occur at onset or more often along the chronic course of the disease. Symptoms and signs are dyspnea on minor exertion, orthopnea, nocturnal awakenings, excessive daytime sleepiness, fatigue, morning headache, poor concentration, and difficulty in clearing bronchial secretions. The "20/30/40 rule" has been proposed to early identify GBS patients at risk for respiratory failure. The mechanical in-exsufflator is a device that assists ALS patients in clearing bronchial secretions. Noninvasive ventilation is a safe and helpful support, especially in ALS, but has some contraindications. Myasthenic crisis is a clinical challenge and is associated with substantial morbidity including prolonged mechanical ventilation and 5%-12% mortality. Emergency room physicians and consultant pulmonologists and neurologists must know such respiratory risks, be able to recognize early signs, and treat properly.

Noninvasive and invasive mechanical ventilation for neurologic disorders

Patients with acute neurologic injuries frequently require mechanical ventilation due to diminished airway protective reflexes, cardiopulmonary failure secondary to neurologic insults, or to facilitate gas exchange to precise targets. Mechanical ventilation enables tight control of oxygenation and carbon dioxide levels, enabling clinicians to modulate cerebral hemodynamics and intracranial pressure with the goal of minimizing secondary brain injury. In patients with acute spinal cord injuries, neuromuscular conditions, or diseases of the peripheral nerve, mechanical ventilation enables respiratory support under conditions of impending or established respiratory failure. Noninvasive ventilatory approaches may be carefully considered for certain disease conditions, including myasthenia gravis and amyotrophic lateral sclerosis, but may be inappropriate in patients with Guillain-Barré syndrome or when relevant contra-indications exist. With regard to discontinuing mechanical ventilation, considerable uncertainty persists about the best approach to wean patients, how to identify patients ready for extubation, and when to consider primary tracheostomy. Recent consensus guidelines highlight these and other knowledge gaps that are the focus of active research efforts. This chapter outlines important general principles to consider when initiating, titrating, and discontinuing mechanical ventilation in patients with acute neurologic injuries. Important disease-specific considerations are also reviewed where appropriate.

Predictors of outcome in patients with myasthenic crisis undergoing non-invasive mechanical ventilation: A retrospective 20 year longitudinal cohort study from a single Italian center

About 20% of patients with myasthenia gravis (MG) may develop myasthenic crisis (MC) requiring ventilation, either invasive (MV) or non-invasive (NIV) and intensive unit care (ICU). NIV failure in patients with MC can occur up to 60% of cases admitted to ICU. Moreover it is not known the outcome of MC receiving NIV. Purpose of this study was to identify predictors of outcome in MC who underwent non-invasive ventilator support outside ICU setting. We enrolled 90 patients, 53 females and 37 males admitted to University Hospital of Modena (Italy) between January 2000 and September 2020. Median age at MC was 65 years. Thirty-four patients (37.8%) required MV. Thymectomy was performed in 45 cases, associated with thymoma in 55%, with hyperplastic thymus in 33%. First-line treatment was plasmaexchange (38.8%) or intravenous immunoglobulins (45.6%). Males exhibited higher risk of MV than females .Patients in MV were treated with plasmaexchange as first-line therapy . Our in-hospital mortality rate was low. Nine patients underwent tracheostomy which was significantly related to male gender. Comorbidities had significant effect on length of ICU .Our study confirms as predictors of prognosis in our patients male gender, older age at onset, infections as trigger, pneumonia.

Neuromuscular Disorders in the Intensive Care Unit

PURPOSE OF REVIEW

This article discusses the pathophysiology, presentation, diagnosis, treatment, and prognosis of common neuromuscular disorders seen in the intensive care unit, including Guillain-Barré syndrome, myasthenia gravis, and intensive care unit-acquired weakness.

RECENT FINDINGS

Guillain-Barré syndrome can have an excellent prognosis if patients are diagnosed early, appropriately treated, and monitored for complications, including respiratory failure and dysautonomia. Intensive care unit-acquired weakness increases overall mortality in patients who are critically ill, and distinguishing between critical illness myopathy and critical illness polyneuropathy may have important prognostic implications.

SUMMARY

Neuromuscular disorders are not rare in the intensive care unit setting, and precise identification and treatment of these conditions can greatly impact long-term outcomes.

Risk factors of prolonged ventilation after thymectomy in thymoma myasthenia gravis patients

BACKGROUND

To explore the risk factors for prolonged ventilation after thymectomy in patients with thymoma associated with myasthenia gravis (TAMG).

METHODS

We reviewed the records of 112 patients with TAMG after thymectomy between January 2010 and December 2019 in Peking University People's Hospital. Demographic, pathological, preoperative data and the Anesthesia, surgery details were assessed with multivariable logistic regression analysis to predict the risk of prolonged ventilation after thymectomy. A nomogram to predict the probability of post-thymectomy ventilation was constructed with R software. Discrimination and calibration were employed to evaluate the performance of the nomogram.

RESULTS

By multivariate analysis, male, low vital capacity (VC), Osserman classification (IIb, III, IV), total intravenous anesthesia, and long operation time were identified as the risk factors and entered into the nomogram. The nomogram showed a robust discrimination, with an area under the receiver operating characteristic curve (AUC) of 0. 835 (95% confidence interval [CI], 0.757-0.913). The calibration plot indicated that the nomogram-predicted probabilities compared very well with the actual probabilities (Hosmer-Lemeshow test: P = 0.921).

CONCLUSION

The nomogram is a valuable predictive tool for prolonged ventilation after thymectomy in patients with TAMG.

Early Tracheostomy Is Associated With Shorter Ventilation Time and Duration of ICU Stay in Patients With Myasthenic Crisis-A Multicenter Analysis

BACKGROUND

Myasthenic crisis (MC) requiring mechanical ventilation (MV) is a rare and serious complication of myasthenia gravis. Here we analyzed the frequency of performed tracheostomies, risk factors correlating with a tracheostomy, as well as the impact of an early tracheostomy on ventilation time and ICU length of stay (LOS) in MC.

METHODS

Retrospective chart review on patients treated for MC in 12 German neurological departments between 2006 and 2015 to assess demographic/diagnostic data, rates and timing of tracheostomy and outcome.

RESULTS

In 107 out of 215 MC (49.8%), a tracheostomy was performed. Patients without tracheostomy were more likely to have an early-onset myasthenia gravis (27 [25.2%] vs 12 [11.5%], p = 0.01). Patients receiving a tracheostomy, however, were more frequently suffering from multiple comorbidities (20 [18.7%] vs 9 [8.3%], p = 0.03) and also the ventilation time (34.4 days ± 27.7 versus 7.9 ± 7.8, p < 0.0001) and ICU-LOS (34.8 days ± 25.5 versus 12.1 ± 8.0, p < 0.0001) was significantly longer than in non-tracheostomized patients. Demographics and characteristics of the course of the disease up to the crisis were not significantly different between patients with an early (within 10 days) compared to a late tracheostomy. However, an early tracheostomy correlated with a shorter duration of MV at ICU (26.2 days ± 18.1 versus 42.0 ± 33.1, p = 0.006), and ICU-LOS (26.2 days ± 14.6 versus 42.3 ± 33.0, p = 0.003).

CONCLUSION

Half of the ventilated patients with MC required a tracheostomy. Poorer health condition before the crisis and late-onset MG were associated with a tracheostomy. An early tracheostomy (≤ day 10), however, was associated with a shorter duration of MV and ICU-LOS by 2 weeks.

Myasthenic crisis demanding mechanical ventilation: A multicenter analysis of 250 cases

OBJECTIVE

To determine demographic characteristics, clinical features, treatment regimens, and outcome of myasthenic crisis (MC) requiring mechanical ventilation (MV).

METHODS

Analysis of patients who presented with MC between 2006 and 2015 in a German multicenter retrospective study.

RESULTS

We identified 250 cases in 12 participating centers. Median age at crisis was 72 years. Median duration of MV was 12 days. Prolonged ventilation (>15 days) depended on age (p = 0.0001), late-onset myasthenia gravis (MG), a high Myasthenia Gravis Foundation of America Class before crisis (p = 0.0001 for IVb, odds ratio [OR] = infinite), number of comorbidities (>3 comorbidities: p = 0.002, OR 2.99), pneumonia (p = 0.0001, OR 3.13), and resuscitation (p = 0.0008, OR 9.15). MV at discharge from hospital was necessary in 20.5% of survivors. Patients with early-onset MG (p = 0.0001, OR 0.21), thymus hyperplasia (p = 0.002, OR 0), and successful noninvasive ventilation trial were more likely to be ventilated for less than 15 days. Noninvasive ventilation in 92 cases was sufficient in 38%, which was accompanied by a significantly shorter duration of ventilation (p = 0.001) and intensive care unit (ICU) stay (p = 0.01). IV immunoglobulins, plasma exchange, and immunoadsorption were more likely to be combined sequentially if the duration of MV and the stay in an ICU extended (p = 0.0503, OR 2.05). Patients who received plasma exchange or immunoadsorption as first-line therapy needed invasive ventilation significantly less often (p = 0.003). In-hospital mortality was 12%, which was significantly associated with the number of comorbidities (>3) and complications such as acute respiratory distress syndrome and resuscitation. Main cause of death was multiorgan failure, mostly due to sepsis.

CONCLUSION

Mortality and duration of MC remained comparable to previous reports despite higher age and a high disease burden in our study. Prevention and treatment of complications and specialized neurointensive care are the cornerstones in order to improve outcome.

Practical approach to respiratory emergencies in neurological diseases

Many neurological diseases may cause acute respiratory failure (ARF) due to involvement of bulbar respiratory center, spinal cord, motoneurons, peripheral nerves, neuromuscular junction, or skeletal muscles. In this context, respiratory emergencies are often a challenge at home, in a neurology ward, or even in an intensive care unit, influencing morbidity and mortality. More commonly, patients develop primarily ventilatory impairment causing hypercapnia. Moreover, inadequate bulbar and expiratory muscle function may cause retained secretions, frequently complicated by pneumonia, atelectasis, and, ultimately, hypoxemic ARF. On the basis of the clinical onset, two main categories of ARF can be identified: (i) acute exacerbation of chronic respiratory failure, which is common in slowly progressive neurological diseases, such as movement disorders and most neuromuscular diseases, and (ii) sudden-onset respiratory failure which may develop in rapidly progressive neurological disorders including stroke, convulsive status epilepticus, traumatic brain injury, spinal cord injury, phrenic neuropathy, myasthenia gravis, and Guillain-Barré syndrome. A tailored assistance may include manual and mechanical cough assistance, noninvasive ventilation, endotracheal intubation, invasive mechanical ventilation, or tracheotomy. This review provides practical recommendations for prevention, recognition, management, and treatment of respiratory emergencies in neurological diseases, mostly in teenagers and adults, according to type and severity of baseline disease.

Intravenous immunoglobulin to prevent myasthenic crisis after thymectomy and other procedures can be omitted in patients with well-controlled myasthenia gravis

Background:

Myasthenic crisis (MC) is a potentially life-threatening complication of myasthenia gravis. Its precipitating factors include surgical procedures, particularly thymectomy. The role of preoperative intravenous immunoglobulin (IVIg) in preventing MC in patients scheduled for thymectomy and other surgery with general anaesthesia is unknown. Our objective was to test the hypothesis that preoperative IVIg is effective in preventing myasthenic crisis in patients with myasthenia gravis scheduled for surgery under general anaesthesia, including thymectomy.

Methods:

A prospective, randomized, double-blind, single-centre study was conducted over a 4-year period. The treatment group received IVIg, 0.4 g/kg/day preoperatively for 5 consecutive days, and the placebo group received saline solution under the same conditions. The two groups were age-matched, with similar functional status, and Myasthenia Gravis Foundation of America class. All patients had well-controlled myasthenia gravis with minimal manifestations before surgery. The primary outcome measured was MC. Intubation times, time in the recovery room, number of postoperative complications, and days of hospitalization were the secondary outcomes measured.

Results:

A total of 47 patients were randomized, 25 to the IVIg group and 22 to placebo. There were 19 men and 28 women, with a mean age of 58.6 years, mean body mass index of 27.8 kg/m², and mean acetylcholine receptor antibodies of 12.9 nmol/l. The mean forced vital capacity was 84.4%. The mean quantitative myasthenia gravis sum score was 6.3. Ten patients (five in each arm) had a history of MC. Thymectomy was performed in 16 patients. Only one patient in the placebo group presented with MC requiring non-invasive ventilation (but no reintubation) for 6 days. Neither differences between groups in the univariate analysis nor risk factors for MC in the multivariate analysis were found.

Conclusions:

Preoperative IVIg to prevent MC does not appear to be justified in well-controlled myasthenia gravis patients. This study provides class I evidence that preparation with IVIg to prevent MC is not necessary in well-controlled myasthenia gravis patients scheduled for surgery with general anaesthesia.

Anti-MuSK-Positive Myasthenic Crisis in a 7-Year-Old Female

A seven-year-old African American female with anti-MuSK-positive Juvenile Myasthenia Gravis collapsed while at school from progressively worsening weakness and dyspnea. On initial emergency department presentation, she required 15 liters per minute of supplemental oxygen to maintain oxygen saturation above 92%. Initial pulmonary function tests and venous blood gas led to the decision to place her on noninvasive positive pressure ventilation (NPPV) with BiPAP in the emergency department. Due to worsening hypercarbia, she later required mechanical intubation in the PICU and underwent IVIG therapy followed by plasmapheresis in order to achieve a stable discharge from the hospital. A respiratory virus panel PCR was positive for influenza A, influenza B, and rhinovirus, likely precipitating the respiratory failure and myasthenic crisis in this seven-year-old patient. Given the rarity of this condition, this case report is to provide further education to the clinician managing severe, prepubertal Juvenile Myasthenia Gravis and myasthenic crisis.

Mortality Prediction in Patients Undergoing Non-Invasive Ventilation in Intermediate Care

Background

Intermediate Care Units (ImCU) have become an alternative scenario to perform Non-Invasive Ventilation (NIV). The limited number of prognostic studies in this population support the need of mortality prediction evaluation in this context.

Objective

The objective of this study is to analyze the performance of Simplified Acute Physiology Score (SAPS) II and 3 in patients undergoing NIV in an ImCU. Additionally, we searched for new variables that could be useful to customize these scores, in order to improve mortality prediction.

Design

Cohort study with prospectively collected data from all patients admitted to a single center ImCU who received NIV. The SAPS II and 3 scores with their respective predicted mortality rates were calculated. Discrimination and calibration were evaluated by calculating the area under the receiver operating characteristic curve (AUC) and with the Hosmer-Lemeshow goodness of fit test for the models, respectively. Binary logistic regression was used to identify new variables to customize the scores for mortality prediction in this setting.

Patients

The study included 241 patients consecutively admitted to an ImCU staffed by hospitalists from April 2006 to December 2013.

Key Results

The observed in-hospital mortality was 32.4% resulting in a Standardized Mortality Ratio (SMR) of 1.35 for SAPS II and 0.68 for SAPS 3. Mortality discrimination based on the AUC was 0.73 for SAPS II and 0.69 for SAPS 3. Customized models including immunosuppression, chronic obstructive pulmonary disease (COPD), acute pulmonary edema (APE), lactic acid, pCO2 and haemoglobin levels showed better discrimination than old scores with similar calibration power.

Conclusions

These results suggest that SAPS II and 3 should be customized with additional patient-risk factors to improve mortality prediction in patients undergoing NIV in intermediate care.

Protocol-directed weaning from mechanical ventilation in neurological patients: a randomised controlled trial and subgroup analyses based on consciousness

OBJECTIVES

To assess whether a weaning protocol reduces the mechanical ventilation (MV) duration compared to physician's judgement-based weaning in neurological patients and to determine whether patient consciousness influences this reduction.

METHODS

A randomised controlled trial was conducted in a neurological intensive care unit (NCU) of a tertiary hospital; 144 patients requiring MV for more than 24 hours were randomly allocated to protocol-directed (intervention) (n = 71) or physician-directed (control) group (n = 73).

RESULTS

The intervention group displayed a significantly shorter median weaning time than the control group (2.00 vs 5.07 days, P < 0.05). The median MV duration tended to be shorter in the intervention group (10.8 vs 14.2 days, P = 0.106). The median length of NCU stay was 19.0 and 26.1 days in the intervention and control groups, respectively (P = 0.063). The median NCU cost was 9.26 × 10(4) and 12.24 × 10(4) ¥ in the intervention and control groups, respectively (P = 0.059). The unsuccessful weaning, ventilator-associated pneumonia (VAP) and mortality rates were similar between the groups. Among conscious patients, the median weaning time (2.00 vs 7.00 days, P < 0.05) and the median MV duration (8.8 vs 18.0 days, P = 0.017) were significantly reduced in the intervention group. Among unconscious patients, the intervention group displayed a reduced median weaning time (1.00 vs 3.10 days, P < 0.05), but not median MV duration (11.6 vs 11.1 days, P = 0.702), compared to the control group.

CONCLUSION

Protocol-directed weaning reduces weaning time, MV duration, length of NCU stay and NCU cost in neurological patients, and these effects are more significant in conscious patients than in unconscious patients.

Myasthenic Crisis in an Elderly Patient with Positive Antibodies against Acetylcholine and Anti-MuSK, Successfully Treated with Noninvasive Mechanical Ventilation

Myasthenia gravis is an autoimmune disease characterized by muscle weakness. Subjects with antibodies against acetylcholine usually have greater ocular symptoms, lower bulbar weakness, and fewer respiratory complications, compared to individuals with anti-MuSK antibodies. The presence of positivity to both types of antibodies in the same patient is uncommon, and the clinical behavior of these individuals is uncertain. A myasthenic crisis is characterized by respiratory and bulbar muscle weakness, causing acute respiratory failure which requires mechanical ventilatory support. We present the case of a 73-year-old man with a medical history of myasthenia gravis and positive antibody titers against acetylcholine and anti-MuSK, who sought for medical assessment because of respiratory tract infection symptoms, dysphagia, and generalized weakness. Initially, no respiratory distress was found. After 24 hours the patient showed respiratory deterioration and neurological impairment. Endotracheal intubation was rejected, so ventilatory support with noninvasive ventilation was started. The patient was supported by intense respiratory therapy, and infusion of immunoglobulin was initiated. The individual responded favorably, improving his general condition. Weaning from noninvasive mechanical ventilation was possible after six days. Our case illustrates that noninvasive ventilation, properly supported by intense respiratory therapy, can be a great option to avoid intubation in the myasthenic patient.

Predictors of extubation failure in neurocritical patients identified by a systematic review and meta-analysis

Background

Prediction of extubation failure, particularly in neurocritical patients, is unique and controversial. We conducted a systematic review and meta-analysis to identify the risk factors for extubation failure in these patients.

Methods

A literature search of databases (MEDLINE, EMBASE, the Cochrane Library, and Web of Science) was performed up to August of 2013 to identify trials that evaluated extubation failure predictors. Included trials were either prospective or retrospective cohort studies.

Results

Nine studies involving 928 participants were included. The systematic review and meta-analysis revealed that the following were predictive for extubation failure: pneumonia, atelectasis, mechanical ventilation of >24 h, a low Glasgow Coma Scale score (7–9T) (OR = 4.96, 95% CI = 1.61–15.26, P = 0.005), the inability to follow commands (OR = 2.07, 95% CI = 1.15–3.71, P = 0.02), especially the command to close the eyes, thick secretion, and no intact gag reflex. Meanwhile, the following were not predictive for extubation failure: sex, secretion volume, coughing upon suctioning, and the inability to follow one command among showing two fingers, wiggling the toes, or coughing on command. Additionally, some traditional weaning parameters were shown to poorly predict extubation failure in neurocritical patients.

Conclusions

Besides pneumonia, atelectasis, and the duration of mechanical ventilation, other factors that should be taken into consideration in the prediction of extubation failure when neurocritical patients are weaned from tracheal intubation include neurologic abilities (Glasgow Coma Scale score and following commands), the secretion texture, and the presence of a gag reflex.

The myasthenic patient in crisis: an update of the management in Neurointensive Care Unit

Myasthenia gravis (MG) is an autoimmune disorder affecting neuromuscular transmission leading to generalized or localized muscle weakness due most frequently to the presence of autoantibodies against acetylcholine receptors in the postsynaptic motor end-plate. Myasthenic crisis (MC) is a complication of MG characterized by worsening muscle weakness, resulting in respiratory failure that requires intubation and mechanical ventilation. It also includes postsurgical patients, in whom exacerbation of muscle weakness from MG causes a delay in extubation. MC is a very important, serious, and reversible neurological emergency that affects 20-30% of the myasthenic patients, usually within the first year of illness and maybe the debut form of the disease. Most patients have a predisposing factor that triggers the crisis, generally an infection of the respiratory tract. Immunoglobulins, plasma exchange, and steroids are the cornerstones of immunotherapy. Today with the modern neurocritical care, mortality rate of MC is less than 5%.

Myasthenic crisis

Myasthenic crisis is a complication of myasthenia gravis characterized by worsening of muscle weakness, resulting in respiratory failure that requires intubation and mechanical ventilation. Advances in critical care have improved the mortality rate associated with myasthenic crisis. This article reviews the epidemiology of myasthenic crisis and discusses patient evaluation. Therapeutic options including mechanical ventilation and pharmacological and surgical treatments are also discussed.

Predictors for good functional outcome after neurocritical care

Introduction

There are only limited data on the long-term outcome of patients receiving specialized neurocritical care. In this study we analyzed survival, long-term mortality and functional outcome after neurocritical care and determined predictors for good functional outcome.

Methods

We retrospectively investigated 796 consecutive patients admitted to a non-surgical neurologic intensive care unit over a period of two years (2006 and 2007). Demographic and clinical parameters were analyzed. Depending on the diagnosis, we grouped patients according to their diseases (cerebral ischemia, intracranial hemorrhage (ICH), subarachnoid hemorrhage (SAH), meningitis/encephalitis, epilepsy, Guillain-Barré syndrome (GBS) and myasthenia gravis (MG), neurodegenerative diseases and encephalopathy, cerebral neoplasm and intoxication). Clinical parameters, mortality and functional outcome of all treated patients were analyzed. Functional outcome (using the modified Rankin Scale, mRS) one year after discharge was assessed by a mailed questionnaire or telephone interview. Outcome was dichotomized into good (mRS ≤ 2) and poor (mRS ≥ 3). Logistic regression analyses were calculated to determine independent predictors for good functional outcome.

Results

Overall in-hospital mortality amounted to 22.5% of all patients, and a good long-term functional outcome was achieved in 28.4%. The parameters age, length of ventilation (LOV), admission diagnosis of ICH, GBS/MG, and inoperable cerebral neoplasm as well as Therapeutic Intervention Scoring System (TISS)-28 on Day 1 were independently associated with functional outcome after one year.

Conclusions

This investigation revealed that age, LOV and TISS-28 on Day 1 were strongly predictive for the outcome. The diagnoses of hemorrhagic stroke and cerebral neoplasm leading to neurocritical care predispose for functional dependence or death, whereas patients with GBS and MG are more likely to recover after neurocritical care.

Airway limitation and exercise intolerance in well-regulated myasthenia gravis patients

OBJECTIVES

Myasthenia gravis (MG) is an autoimmune disease of neuromuscular synapses, characterized by muscular weakness and reduced endurance. Remission can be obtained in many patients. However, some of these patients complain of fatigue. The aim of this study was to assess exercise capacity and lung function in well-regulated MG patients.

PATIENTS AND METHODS

Ten otherwise healthy MG patients and 10 matched controls underwent dynamic spirometry, and a ramped symptom-limited bicycle exercise test. Spirometric variables included forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and maximum voluntary ventilation (MVV). Exercise variables included maximal oxygen uptake (VO(2) max), anaerobic threshold (VO(2) AT) maximum work load (W), maximum ventilation (VE max), and limiting symptom.

RESULTS

Myasthenia gravis patients had significantly lower FEV1/FVC ratio than controls. This was more marked in patients on acetylcholine esterase inhibitors. On the contrary, patients not using acetylcholine esterase inhibitors had a significantly lower exercise endurance time.

CONCLUSION

Well-regulated MG patients, especially those using pyridostigmine, tend to have an airway obstruction. The modest airway limitation might be a contributing factor to their fatigue. Patients who are not using acetylcholinesterase inhibitor seem to have diminished exercise endurance in spite of their clinically complete remission.