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 Table of Contents  
Year : 2020  |  Volume : 14  |  Issue : 2  |  Page : 74-79

Effect of early mobility in mechanically ventilated patients with myasthenia crisis on duration of mechanical ventilation and length of intensive care unit stay

1 Neuro-Physiotherapy Unit, Neurosciences Centre, All India Institute of Medical Sciences, New Delhi, India
2 Department of Therapies and Health Sciences, Manav Rachna International University, Faridabad, Haryana, India
3 Department of Neurology, All India Institute of Medical Sciences, New Delhi, India

Date of Submission28-Jul-2020
Date of Acceptance02-Oct-2020
Date of Web Publication31-Dec-2020

Correspondence Address:
Dr. Shikha Chauhan
(PT), 14 Carmine Drive, Wappingers Falls, NY 12590
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/PJIAP.PJIAP_40_20

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BACKGROUND: Myasthenia crisis (MC) requires mechanical ventilation (MV) which, if prolonged, may lead to multisystem complications. Early mobility, a potent modality, remains underutilized in critically ill patients with neuromuscular diseases.
METHODOLOGY: A prospective, pretest–posttest control group study was conducted on thirty mechanically ventilated patients with MC in intensive care setup in a tertiary care teaching hospital. They were randomly divided into experimental group and control group. Both the groups received standard medical care, chest physiotherapy, range of motion exercises, and nursing care. In addition, the experimental group received strengthening exercises for extremities and progressive mobilization to sitting at bedside, standing, marching, and walking at bedside till the patients were transferred to ward. Duration of ventilation, length of intensive care unit (ICU) stay (LOS), and adverse events were recorded. Independent t-test was used to compare the difference between two groups.
RESULTS: Out of thirty patients, 15 were randomly divided into each group using a sealed envelope method. One participant in experimental group and three in control group could not be weaned off and were tracheostomized at 3 weeks. An intent to treat analysis was done for duration of ventilation (n = 30). A total of 16 ± 4.32 exercise sessions were given in experimental group. Duration of ventilation (8.93 ± 3.95 vs. 13.31 ± 4.71 days; 95% confidence interval [CI] −7.63 to − 1.13, P = 0.011) and LOS (10.48 ± 2.47 vs. 14.26 ± 3.35 days; 95% CI − 6.22 to − 1.34, P = 0.004) were significantly lower in experimental group as compared to the control group. Relative risk reduction of failure to wean off or need for tracheostomy in early mobility group was 67%. Number needed to treat for the prevention of tracheostomy was 8.
CONCLUSION: Early mobilization of mechanically ventilated MC patients is feasible and leads to decrease in the duration of MV, thereby decreasing the length of ICU stay.

Keywords: Critical care physiotherapy, early mobility, neurology intensive care unit, weaning

How to cite this article:
Aggarwal R, Chauhan S, Behari M, Gupta C, Dua V. Effect of early mobility in mechanically ventilated patients with myasthenia crisis on duration of mechanical ventilation and length of intensive care unit stay. Physiother - J Indian Assoc Physiother 2020;14:74-9

How to cite this URL:
Aggarwal R, Chauhan S, Behari M, Gupta C, Dua V. Effect of early mobility in mechanically ventilated patients with myasthenia crisis on duration of mechanical ventilation and length of intensive care unit stay. Physiother - J Indian Assoc Physiother [serial online] 2020 [cited 2022 May 20];14:74-9. Available from: https://www.pjiap.org/text.asp?2020/14/2/74/305843

  Introduction Top

Myasthenia crisis (MC) is defined as respiratory failure occurring in patients with myasthenia gravis (MG) due to worsening of respiratory muscles' strength and endurance.[1] It occurs in approximately 15%–20% of patients with MG.[2],[3] Mechanical ventilation (MV) and prompt respiratory care with intensive monitoring are vital in its management.[1],[4],[5] The cost of critical care,[6] immobility, and hence intensive care unit (ICU) acquired neuromuscular weakness[7] increase manifold with MV, hence prolonging the ICU stay.[8] It becomes particularly challenging in neuromuscular disorders (NMDs) such as MG. Prolonged intubation in MC is also reported to be associated with fever, pneumonia, atelectasis, anemia, diarrhea, and congestive heart failure.[9],[10] Hence, it is prudent to minimize the duration of MV while treating the primary pathology.

Early mobility in critical care is shown to be a potent modality in reducing the duration of MV.[11],[12],[13],[14],[15] Two recent systematic reviews reported early mobility to be associated with improved functional capacity, muscle strength, mobility, health-related quality of life, less duration of MV, and a higher probability of being discharged to home.[16],[17] It is proven to be safe and cost-effective in neurological ICU as well.[11],[12],[15]

However, potential fatigue associated with exercise of intubated patients with NMD poses a challenge to their early mobilization. Yet, it is worth considering that MC is a specific group of NMD which shows periodic fluctuations in muscle strength[3] with a dramatic improvement in strength following the administration of anticholinesterases.[18] Hence, we hypothesized that the benefits of early mobility may be exploited by planning a well-structured exercise program to these patients during the peak effect of their medications. It is the first attempt to study the effects of early mobilization in patients with MC. We planned to evaluate the effects of early mobilization on the duration of MV and length of ICU stay in mechanically ventilated patients with MC.

  Methodology Top

It was a prospective, pretest–posttest control group trial. The study protocol was in accordance with the ethical standards set forth in the Helsinki Declaration of 1975, and a written informed consent was obtained from all the participants. The ethical clearance was obtained from the review committee of university.

A purposive sampling was done to recruit thirty patients with MC (MG Grade 5) who were mechanically ventilated through an endotracheal tube from the neurological ICU at a tertiary care teaching hospital in India. Grading of the patients of MC was assessed using clinical classification for the severity of MG devised by MG Foundation of America Clinical Classification.[19] Hemodynamically stable MC patients between 25 and 55 years of age with at least Grade 3 of muscle power as per the Medical Research Council were recruited within 48 h of intubation. All the patients were on synchronized intermittent mandatory ventilation (SIMV) with pressure support mode and were conscious, cooperative, and were following verbal commands. The exclusion criteria were a requirement of fraction of inspired oxygen [Fraction of oxygen in inspired air (FiO2)] >0.6, positive end-expiratory pressure (PEEP) >10 cm H20, body mass index >30, indwelling femoral sheath, arterial line, history of cardiopulmonary resuscitation during the current hospital stay, and history of hospitalization within 30 days before present admission. Furthermore, the patients who were nonambulatory before admission or those with any other associated neurological, cardiopulmonary, or preexisting cognitive impairment or any orthopedic ailments affecting the participation in the mobility program were excluded from the trial. All the patients were then screened for safety by reviewing medical history, cardiovascular, and pulmonary reserve before initiation and also during the mobilization as per the guidelines given by Stiller and Philips, 2003.[20]

Recruited patients were randomly assigned using a sealed envelope method to either experimental group or control group. The patients in the control group received the conventional treatment, while those in experimental group received early mobility program in addition to conventional treatment. The safety evaluation was done every day during the study period.

Participants in both the groups received standard medical therapy for myasthenia crisis and associated complications. Nutritional support and nursing care including but not limited to frequent change in position, and assistance with activities of daily living such as toileting were provided to all participants. All patients were given standard medical care as per the institutional protocol. Adequate care was taken to prevent sepsis and provide nutrition, humidification of inspired air, and regular endotracheal toileting. Vitals (blood pressure [BP], respiratory rate [RR], temperature, and SpO2), blood chemistry, hematology, tracheal culture, urine culture, chest X-ray, catheter care, and airway care were done as per the institutional protocol. Chest physiotherapy was administered as per requirement. An effort was made to maintain oxygen fraction in inspired air (FiO2) at <0.5 while maintaining adequate oxygenation (SpO2 >95%). Weaning was accomplished by a gradual reduction in the SIMV rate and the level of pressure support. A T-piece trial was given, and the patients were extubated if they had normal bulbar reflexes and satisfactory respiratory pattern and blood gases values.

The early mobility protocol [Figure 1] was administered to the experimental group twice daily, with duration of each session ranging from 30 to 45 min. An attempt was made to progressively increase the patient's activity level as he/she gradually recovered from the crisis. Participants were allowed to rest between exercise sessions and any sign or symptom that indicated intolerance was closely monitored throughout the training session. The control group received a range of motion exercises of all the joints performed twice daily at the bedside and repositioning every 2 h.
Figure 1: The early mobility protocol

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The intervention ended after 3 weeks of intubation or if the participant was tracheostomized or transferred to ward whichever was earlier. The patients were not transferred to ward with endotracheal tube as per institution's protocol. For the purpose of intent to treat analysis, the duration of ventilation was taken as 21 days if the participant could not be weaned till 3 weeks. Following criteria were used to limit or withhold intervention: hypoxia with frequent desaturation below 88%, hypotension (mean arterial pressure <65 mm Hg), RR >35/min, new myocardial infarction/arrhythmia depicted by electrocardiogram and/or depicted by bio-markers, requirement of an increase in the PEEP or a shift to higher support mode of ventilation, extreme fatigue depicted on modified Borg score of > 6/10, and participant unwilling to continue. Any complication/adverse event during the course of study was recorded and managed as per standard protocol.

Outcome measures

Duration of mechanical ventilation

The duration of MV (days) was calculated from the time of commencement of MV in the ICU until the patient was no longer receiving any form of invasive positive pressure ventilation. Intermittent periods of time off MV as part of weaning regimen were considered part of MV duration. Participants not receiving MV for at least 24 h continuously were considered liberated from MV.

Length of intensive care unit stay

Length of ICU stay (days) was calculated from the day of admission to the ICU till the day patient was transferred from the ICU to ward.

Statistical analyses

Statistical software package (SPSS 16.0 by SPSS Inc., South Wacker Drive, 11th Floor, Chicago, IL, USA) was utilized for analysis of data. Comparison between the groups was done using independent t-test. For all statistical analyses, P values of/0.05 were considered to be statistically significant.

  Results Top

A total of thirty patients who met the study criteria were prospectively enrolled in the trial. Out of which, 15 patients were randomly allocated either to an experimental group or control Group. The baseline characteristics of the participants are shown in [Table 1]. Intergroup analysis revealed that there was no statistical difference in the demographic characteristics and ventilator settings between the groups (P > 0.05) at the baseline. One patient in the experimental group and three patients in control group could not be weaned off within 3 weeks of the study period and were tracheostomized. Intent to treat analysis was used to analyze the duration of MV (n = 30), while the data of the remaining 26 patients were used to evaluate the length of ICU stay. Relative risk reduction of failure to wean off or tracheostomy in early mobility group was 67%. The number needed to treat for the prevention of tracheostomy was 8.
Table 1: Baseline characteristics of patients with myasthenia crisis

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Anxiety, fatigue, pain in extremities, breathlessness, tachycardia, transient increase in BP, and disturbance in monitoring were among the adverse events in the experimental group and were managed by counseling and adequate rest in between the protocol. The experimental group received 16 ± 4.32 exercise sessions.

Duration of mechanical ventilation

The mean duration of MV in experimental group was 8.93 ± 3.95 days and 13.31 ± 4.71 days in control group. On between-group analysis, there was a statistical significant difference (95% confidence interval [CI] −7.63 to −1.13, t = −2.76, P = 0.011) in duration of MV.

Length of intensive care unit stay

The mean length of ICU stay for experimental group was 10.48 ± 2.47 days and for control group was 14.26 ± 3.35 days. There was a statistically significant difference (95% CI −6.22 to −1.34, t = −3.23, P = 0.004) in the length of ICU stay in between-group analysis.

  Discussion Top

The present study was intended to evaluate the effect of early mobilization on duration of MV and ICU stay in patients with MC. Results of this study suggest that early mobilization produced a significant reduction in number of days on MV and ICU stay in patients with MC. Adverse effects are few and can be managed effectively.

In line with the previous studies,[11],[12],[13],[18] the present study showed that early mobility in intubated ICU patients is feasible and safe. Furthermore, the early mobility in ICU was associated with statistically significant decreased days on ventilator and reduced ICU stay. The previous studies though reported similar findings[8],[9],[16],[17],[19],[21] but had substantial methodological shortcomings such as small sample size, nonspecific therapeutic interventions, lack of control group, or were done on a heterogeneous group of patients, and moreover, most of them excluded patients with neuromuscular diseases.[17],[22] Lai et al. in 2017 reported a significant decrease in duration of MV (4.7 days vs. 7.5 days) and reduced ICU stay (6.9 days vs. 9.9 days) in patients with acute respiratory failure.[21] Dull and Dull reported that early mobilization alone is effective in restoring airflow and lung volumes toward preoperative values in patients who underwent cardiopulmonary bypass, while there is no additional effect of maximal breathing exercises or incentive spirometry.[23]

Very few studies are available in the literature evaluating the effects of different factors related to the mobilization or exercise therapy on patients with stable neuromuscular diseases.[24],[25],[26] Cup et al.[24] systematically reviewed the effect of exercise and other physical therapies in patients with neuromuscular diseases including motor neuron diseases, MG, dystrophies, and postpolio syndrome. Their analysis showed a level 2 evidence for strengthening exercises in combination with aerobic exercises for patients with muscle disorders. Previous studies have reported the role of respiratory muscle training in reducing respiratory symptoms, increasing respiratory muscle strength and endurance, and may prove useful in delaying the breathing crisis and the need for MV in patients with MG.[25],[26] Varelas et al. endorsed the role of chest physiotherapy and respiratory care in MC patients in decreasing the risk of pulmonary complications.[27]

The present study attempted to overcome the lacunae in existing literature by evaluating the effect of early mobility in MC patients. Fatigue associated with exercise due to worsened muscular endurance during MC was challenging while prescribing exercise in our study sample. A meticulous planning, customized exercise protocol with continuous monitoring, and timing our exercise sessions with the peak effect of medication could enable us to encash the positive effects of early mobility while avoiding the adverse events and complications. The MC patients in the present study were able to participate in progressive “early” activity, where early refers to the time just after initial physiologic stabilization and continuing throughout the ICU stay. Conventionally, early mobilization is often delayed until after ICU discharge. In a study by Martin et al.,[28] this delay was associated with severe physical debility (100% of patients were bedridden at ICU discharge). The mobilization protocol by Morris et al.[29] adopted in the present study is methodical and progressive in nature. Initially, this protocol was developed for patients with acute respiratory failure due to varied conditions requiring MV on admission. We could mobilize all the patients in experimental group without any major adverse event.

Although the underlying mechanisms are not directly studied here, the improvement in the study group could be due to improvement in ventilatory parameters, resulting in early weaning off the ventilator and decrease in the ventilator-associated complications. The upright positioning which was integral to early mobility protocol in this study has documented beneficial effects on minute ventilation, lung volumes, especially functional residual capacity, and ventilation/perfusion matching[30] which might have led to better oxygenation in our patients as well. The reported facilitation of respiratory actions of pectoralis major and other accessory muscles with the upper extremity strengthening exercises[31] might have further facilitated weaning from MV in our population. The mean duration of the crisis was reported to be 11 days.[5] In our study, the mean duration of MV in the early mobility group was 8.9 days, whereas it was 13.3 days in the control group which was statistically significant (P < 0.01). Two of our patients were out of MV as early as 5 days. Morris et al. reported no statistical difference in duration of MV in the early mobilization group versus usual care group (7.9 vs. 9.0 days; P = 0.298).[29] This discrepancy in the result could probably be due to the reason that they included the respiratory failure patients with varied underlying pathologies. Other reasons for this discrepancy could be older study population (54 ± 10.6 vs. 43.3 ± 10.7 years) and inclusion of unconscious patients (15.4%) in their study. The present study showed a statistically significant decrease in the mean length of ICU stay in the protocol group by 4 days (P < 0.001). This is in line with Morris et al.[29] who found that mean ICU stay was 1.4 days less and 3 days shorter hospital stay in protocol group as compared to the control group.

Earlier studies reported a lower rate of complications with early mobility as compared to conventional care.[15] In this study, complications were documented though not put into analysis. Anxiety, fatigue, pain in extremities, breathlessness, tachycardia, transient increase in BP, and disturbance in monitoring were noted intermittently in experimental group, but none of these was threatening or compelled to terminate the early mobility. One patient in the experimental group could not be weaned off and led to tracheostomy. One patient from control group developed pneumonia, while in total, three patients could not be weaned and eventually required tracheostomy.

It was a prospective, individualized trial on hemodynamically stable, alert, and cooperative patients. It was done on a small sample size with no evaluation of long-term implications. The therapist was not blinded, and the weaning risk profile in terms of smoking status, environmental exposure to pollutants, lung functions, family history, etc., before admission were not taken into consideration.

A longitudinal study in future evaluating the long-term effects of such protocols in patients with MC would reveal the functional outcomes of early mobility. Further studies on a larger population to explore dosimetry of mobilization are needed to establish them as regular practices in the ICUs.

  Conclusion Top

Early mobilization of mechanically ventilated patients with MC is feasible, safe and leads to decrease in duration of MV, thereby decreasing the length of ICU stay. The overall result of early mobilization is the prevention of other systemic complications related to MV or ICU stay. These patients require diligent monitoring and supervision during early mobilization.

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Conflicts of interest

There are no conflicts of interest.

  References Top

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