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ORIGINAL ARTICLE
Year : 2012  |  Volume : 60  |  Issue : 2  |  Page : 150--153

Clinical predictors of mechanical ventilation in Guillain-Barré syndrome

Birinder S Paul1, Rohit Bhatia2, Kameshwar Prasad2, MV Padma2, Manjari Tripathi2, MB Singh2,  
1 Department of Neurology, Dayanand Medical College and Hospital, Ludhiana, Punjab, India
2 Department of Neurology, All India Institute of Medical Sciences, New Delhi, India

Correspondence Address:
Birinder S Paul
Department of Neurology, Dayanand Medical College and Hospital, Ludhiana, Punjab
India

Abstract

Background: Patients with Guillain-Barré syndrome (GBS) require assisted ventilation frequently. However, no single factor can predict ventilator requirement. Aims: To identify clinical variables which could predict the need for mechanical ventilation in GBS. Settings and Design: Tertiary hospital-based retrospective and prospective study. Materials and Methods: One hundred and thirty-eight GBS patients studied were divided into two groups ventilated (Group 1) and non-ventilated (Group 2). Parameters assessed included age, gender, associated illness(es), antecedent events, first symptom at onset, time from onset to bulbar involvement, confinement to bed and peak disability, upper limb power and reflexes at nadir, presence of facial weakness, neck muscle weakness and autonomic dysfunction. Statistical Analysis: Multivariate predictors of ventilation were assessed using logistic regression analysis. Results: There were 53 patients in Group 1 and 85 in Group 2. The mean age in the two groups was comparable. On bivariate analysis, simultaneous weakness of upper (UL) and lower (LL) limbs as the initial symptom (P<0.001); UL power less than Grade 3/5 at nadir (P<0.001); presence of neck and bulbar weakness (P<0.001); shorter duration from onset to bulbar weakness and confinement to bed (P=0.001) and bilateral facial involvement (P<0.01) were more frequently associated with the need for ventilation. Preserved reflexes in UL at nadir was significantly associated with absence of the need for mechanical ventilation (P<0.01). On multivariate analysis, factors independently associated with the need for mechanical ventilation included simultaneous motor weakness in UL and LL as the initial symptom (P=0.02), UL power<3/5 (Medical Research Council grade) at nadir (P=0.013) and presence of bulbar weakness (P<0.001). Preserved reflexes in the UL at nadir was independently associated with a lesser need for ventilation (P=0.001). Conclusions: Comprehensive assessment of clinical features may predict the need for mechanical ventilation in patients of GBS.



How to cite this article:
Paul BS, Bhatia R, Prasad K, Padma M V, Tripathi M, Singh M B. Clinical predictors of mechanical ventilation in Guillain-Barré syndrome.Neurol India 2012;60:150-153


How to cite this URL:
Paul BS, Bhatia R, Prasad K, Padma M V, Tripathi M, Singh M B. Clinical predictors of mechanical ventilation in Guillain-Barré syndrome. Neurol India [serial online] 2012 [cited 2020 Oct 20 ];60:150-153
Available from: https://www.neurologyindia.com/text.asp?2012/60/2/150/96383


Full Text

 Introduction



Guillain-Barré Syndrome (GBS) is a common cause of acute neuromuscular paralysis worldwide. The reported incidence rates of GBS range from 0.6 to 4.0/100,000 population. [1] Acute mortality remains relatively high at 5%. [2],[3],[4] Respiratory failure requiring mechanical ventilation remains one of the most serious complications and occurs in approximately 30% of cases. [3],[4] Reduction in vital capacity and bulbar dysfunction undoubtedly indicate a major risk for respiratory failure in these patients. [5] The value of these parameters is limited as these have been used as criteria for starting mechanical ventilation and ventilation is considered indispensable with vital capacity (VC) < 15 ml/kg or severe bulbar dysfunction. [6] These may reflect established respiratory failure rather than an increased risk of future respiratory failure. Respiratory management could be simplified and guidelines for the use of elective intubation and admission to the intensive care unit (ICU) could be developed if accurate clinical predictors of respiratory failure could be identified early in the course of the disease.

 Materials and Methods



It is a retrospective as well as a prospective cohort study of patients with GBS carried out at a territory care centre, All India Institute of Medical Sciences, New Delhi, India between 2002 and 2006. Patients included in the study were 138; 76 were retrospective and 62 were prospective admissions. The diagnosis of GBS was made using the Asbury and Cornblath criteria. [7] Based on the requirement for mechanical ventilation the patients were divided into: ventilated (Group 1) and non-ventilated (Group 2). Patients were intubated in the presence of any of the below-mentioned factors: (1) clinical evidence of the use of accessory muscles, (2) evidence of fatigue of respiratory muscles, (3) presence of severe bulbar weakness with risk of aspiration, (4).Arterial blood gas showing pO2 < 70 mm Hg or pCO2 > 45 mm Hg

Data was collected before the institution of mechanical ventilation in patients who had received ventilation and from onset up to peak disability in those who did not receive ventilation. Clinical parameters of the two groups were then compared. Primary outcome was the requirement for mechanical ventilation. The demographic and clinical variables analyzed included age, sex, co-morbid conditions, antecedent events [fever, upper respiratory infection (URTI), gastrointestinal upset, rash], first symptoms at the onset of illness (motor/sensory/both), pattern of motor involvement (upper limb distal, upper limb proximal, lower limb distal, lower limb proximal or simultaneous upper and lower limb), time from onset of illness to bulbar involvement and confinement to bed, time to peak disability (for non- ventilated from onset to peak weakness and in ventilated patients from onset to intubation), neck muscle weakness, presence (unilateral or bilateral), upper limb power (Medical Research Council grade) at peak disability and reflexes at peak disability.

Statistical analysis

Baseline characteristics between the two groups were examined by means of the 't ' test and Fischer's exact test for continuous and categorical variables respectively. Multivariate predictors of ventilation were assessed using logistic regression analysis using a backward elimination method. Crude odds ratio and multivariate odds ratio were calculated together with corresponding 95% confidence intervals predictive of mechanical ventilation. Statistical significance was taken as a two-sided P<0.05. The SPSS statistical package (Version 10.0) was used for all analysis.

 Results



A total of 138 patients were included in the study, 76 patients were retrospective (30 were in Group 1 and 40 in Group 2) and 62 were prospective (24 in Group 1 and 38 in Group 2) admissions. There were 53 patients (39%) in Group 1 and 85 (61%) in Group 2. Demographic and clinical characteristics of each group are summarized in [Table 1]. There was no statistically significant difference between the two groups in age and presence of any associated co-morbidity. Presence of URTI as one of the antecedent illnesses was significantly associated with the non-ventilated group (P=0.009). Simultaneous upper limb (UL) and lower limb (LL) involvement was also more significant in Group1 (P=0.008). Forty-nine (92.5%) patients in Group 1 had neck weakness compared to 44 (51.8%) patients in Group 2 (P<0.001). Forty-nine (92.5%) patients in Group 1 had bulbar weakness compared to 24 (28.2%) patients in Group 2 (P<0.001). Shorter duration from onset to bulbar involvement (P=0.001) as well as confinement to bed (=0.001) was significantly associated with the need for mechanical ventilation. Upper limb motor power < 3/5 at peak disability was significantly observed in Group 1 than in Group 2 (94.3% vs. 38.8%, P<0.001). Bilateral facial nerve involvement was observed more frequently in the patients within Group 1 (P<0.001). In Group 1, 94.3% patients had areflexia in the UL whereas only 5.7% of patients with preserved reflexes in the UL at nadir required ventilation. In the non-ventilated group 43.5% patients had areflexia in the UL whereas 47.1% had preserved reflexes. Preserved UL reflexes at peak disability signified a lesser need for ventilation (P<0.001) as summarized in [Table 2]. In summary, univariate analysis revealed that presence of upper respiratory infection as one of the antecedent events, neck and bulbar weakness (P<0.001), simultaneous onset of motor weakness in UL and LL as the initial symptom (P<0.001) with upper limb power < 3 at nadir (P<0.001), shorter duration from onset to bulbar weakness and confinement to bed (P=0.001), and bilateral facial involvement (P<0.01) were more frequently associated with the need for ventilation. Preservation of reflexes in the UL limbs at was significantly associated with absence of need for ventilation (P<0.01). Using multiple logistic regression [Table 3] with mechanical ventilation as the independent variable, simultaneous onset of motor weakness of UL and LL as the initial symptom (P=0.02) with UL power grade < 3/5 at nadir (P=0.013) and bulbar weakness (P<0.001) were more frequently associated with the need for mechanical ventilation. Preserved reflexes in UL at nadir also independently predicted the absence of need for mechanical ventilation (P=0.001).{Table 1}{Table 2}{Table 3}

 Discussion



In this study, 39% of patients required mechanical ventilation. Independent predictors of the need for mechanical ventilation included simultaneous onset of motor weakness of upper and lower limbs as the initial symptom with upper limb power grade < 3/5 at nadir and bulbar weakness. Preserved reflexes in upper limbs at nadir also independently predicted the avoidance of mechanical ventilation. Though the presence of history of upper respiratory tract infection as one of the antecedent illnesses was significantly associated with patients who did not require mechanical ventilation on bivariate analysis, this did not independently predict the need for mechanical ventilation on multivariate analysis. This may be due to the compounding effect of the other variables. Further studies with large number of patients are required to evaluate the significance of antecedent events in predicting the need for mechanical ventilation.

Since bedside spirometer is not routinely available in peripheral hospitals in developing countries and the presence of severe bifacial weakness may influence the results, vital capacity was not taken as a clinical variable in the present study. This study suggests that focusing on clinical history and signs may predict the course of GBS within the first week of onset. In this study neck weakness was identified in a high proportion of patients (92.5%) who subsequently required ventilation although this did not emerge as an independent predictor unlike the upper limb power, possibly because of the strong correlation between the two (Pearson's correlation coefficient 0.476). Bulbar weakness is directly related to the requirement for intubation due to lack of oral and pharyngeal protective mechanisms in these patients and qualifies as one of the indications for early elective intubation in patients of GBS. Presence of reflexes may signify less severe illness and therefore reduced need for ventilatory support. In our study we have separately evaluated the preservation of deep tendon reflexes in the upper limb at peak disability as the criteria for mechanical ventilation. Christa and colleagues [8] developed a clinical scoring system for predicting respiratory failure in patients with GBS within the first week of onset. They found short duration between onset and weakness with low MRC sum score along with presence of facial and or bulbar weakness were the main predictors of mechanical ventilation; these clinical variables were also reproducible in our study. Another study of 722 patients of GBS showed that shorter period between onset and hospitalization (< seven days) was independently associated with the need for mechanical ventilation. [9],[10] The discrepancy between this study and the present study may be attributable to the difference in methodology and number of patients. Tarek et al.,[9] assessed variables collected at admission whereas we studied variables collected between admission and intubation in patients who received ventilator support or peak disability in the non-ventilated group. In their study, although upper limb power was not quantified, inability to lift elbows above the bed was significantly associated with the need for mechanical ventilation. [9] It has also been observed that patients who require ventilation tend to have more severe disease evidenced by the presence of bulbar dysfunction and bifacial palsy. [11] Our results show that early onset of bulbar weakness should be carefully examined and periodically assessed in patients of GBS as it independently predicts the need for assisted ventilation. Our study also observed the association of bifacial palsy and increased likelihood of mechanical ventilation but it did not emerge as an independent variable probably due to its strong correlation with presence of bulbar involvement.

While inherently unpredictable, the course of patients with severe GBS can be predicted to some extent on the basis of clinical characteristics. Our results may allow the identification of GBS patients at admission who are likely at high risk of developing respiratory failure in the course of the illness. Simultaneous onset of weakness in upper and lower limbs, upper limbs' power grade < 3/5 and bulbar involvement should be taken as warning signs. At the same time preserved upper limbs' reflexes at nadir of illness signify a lesser likelihood for ventilator support. These factors alone or in combination may not only necessitate immediate respiratory support but may strongly warn of an impending respiratory crisis and therefore aid in timely referral to tertiary care centers thereby improving the care and outcomes. Regular assessment of patients with these simple bedside measurements should continue until a clear and sustained improvement is observed.

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