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After patients have been intubated for a sufficient time during the earliest phase of SCI treatment, a decision must be made as to whether patients will 1) remain on long-term mechanical ventilation through the endotracheal tube, 2) receive a tracheostomy for long-term ventilation or to assist in weaning, or 3) will be extubated and breathing independently. Traditionally, immediate extubation has been viewed as risky and often leads to pulmonary infections or the need for urgent reintubation. Alternatively, long-term ventilation through an endotracheal tube prolongs the weaning process and the duration of hospital stay. The routine practice has been to receive a tracheostomy to initiate weaning and accelerate discharge from the hospital and not be as abrupt as extubation (Berlly & Shem, 2007). However, in patients who tolerate independent breathing and are weaned successfully off the ventilator, respiratory muscle training or acute physiotherapy can be initiated. Acute physiotherapy is an emerging non-invasive option to help patients resume normal pulmonary functioning and timely discharge. Early prophylactic treatment in the form of physiotherapy has been shown to improve diaphragm function and reduce secretions in patients with acute SCI (McMichan et al. 1980). Assisted coughing, intermittent positive pressure breathing, and regular changes in body positioning are some of the techniques used to help keep patients’ airways clear and breathing independently (Berney et al. 2002). In addition, breathing exercises and diaphragm strengthening can also improve lung functioning and assist in weaning from mechanical ventilation. Resistive inspiratory muscle training (RIMT) and abdominal weights training (Gross et al. 1980; Lin et al. 1999) as well as cough training combined with functional electrical stimulation (McBain et al. 2013) are techniques that have been implemented for physiotherapy in chronic SCI patients. RIMT (Derrickson et al. 1992; Postma et al. 2014), expiratory resistive muscle training (Roth et al. 2010) and abdominal weights training (Derrickson et al. 1992) have been studied in the acute SCI population and are reviewed below.

Table 8. Effect of Respiratory Muscle Training on Pulmonary Function during Acute SCI

Author Year

Country

Research Design

PEDro

Sample Size

MethodsOutcomes
 

Postma et al. (2014)

The Netherlands

RCT

PEDro=7

N=40

Population: Resistive inspiratory muscle training group (RIMT): Mean age: 47.1 yr; Gender: male=20, female=1; Control Group: Mean age: 46.6 yr; Gender: male=15, female=4; Level of injury: T12 and above; Severity of injury: complete=24, incomplete=16.

Intervention: Patients were randomly assigned to receive usual rehabilitation care plus RIMT with a threshold trainer (RIMT group), or usual rehabilitation care only (control group).

Outcome Measures: The following at baseline, after 8 weeks of intervention, 8 weeks after intervention, 1 yr after discharge from inpatient rehabilitation: maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow rate, maximum ventilation volume, health-related quality of life (HRQoL), and 36-item short-form health survey (SF-36).

Chronicity: Median number of days since injury was 74 (RIMT group) and 88 (control group).

1.     MIP improved more in the RIMT group compared with the control group 1 week after the intervention period (mean difference=11.67 cm H2O, p=0.002); this difference was no longer significant 8 weeks after the intervention period (p=0.065) or at 1 yr after discharge from inpatient rehabilitation (p=0.271).

2.     No other between-group differences were found in any of the other measures of respiratory function.

3.     The RIMT group improved more in mental health compared with the control group 1 week after the intervention period (p=0.006).

Effect Sizes: Forest plot of standardized mean differences (SMD ± 95%C.I.) as calculated from pre- and post-intervention data.

 

Roth et al. (2010)

USA

RCT

PEDro=4

N=29

 

Population: Resistance Training Group: Mean age: 31.1 yr; Gender: male=81%, female=19%; Sham Training Group: Mean age: 28.9 yr; Gender: male=69%, female=31%; Level of injury: C4-C7, T1; Severity of injury: complete.

Intervention: Patients were randomly assigned to either expiratory muscle resistance training or sham training for a total of 6 weeks.

Outcome Measures: The following before and after the training program: forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximum expiratory pressure (MEP), maximum inspiratory pressure (MIP), inspiratory capacity, expiratory reserve volume (ERV), total lung capacity (TLC), functional residual capacity (FRC), and residual volume (RV).

Chronicity: Patients were invited to participate in the study if the SCI was recent and had occurred within 6 months’ time. No further information regarding time since injury was provided.

1.     Multivariate analysis did not reveal any significant differences between the resistance training and sham training groups for any of the pulmonary function tests (p=0.22).

2.     Univariate analysis revealed significant improvements in FVC (p=0.02), FEV1 (p=0.02), ERV (p=0.04), MIP (p=0.002), and MEP (p<0.001) in the resistance training group.

3.     Univariate analysis revealed significant improvements in FVC (p=0.04), FEV1 (p=0.01) and ERV (p<0.01) in the sham training group.

 

 

 

 

 

Derrickson et al. (1992)

USA

RCT

PEDro=3

N=11

 

 

 

 

 

Population: Age range: 16-41 yr; Gender: male=6, female=5; Level of injury: C4-5 to C7; Severity of injury: complete.

Intervention: Patients were randomly assigned to receive resistive inspiratory muscle training (RIMT) or abdominal weights (AbWts) training for 7 weeks. Training sessions consisted of two 15-minute treatments each day, 5 days a week.

Outcome Measures: The following after one week and seven weeks: forced vital capacity (FVC), inspiratory capacity (IC), maximal voluntary ventilation (MVV), peak expiratory flow (PEF) rate, and increased inspiratory mouth pressure (PImax).

Chronicity: Time since injury was an average of 12 days (RIMT group) and 25 days (AbWts group).

Between group comparison:

1.     There were no significant differences in FVC, MVV, PEFR, PImax, and IC between patients who received RIMT training and those who received AbWts training (p>0.05 in all cases).

Within group comparison:

2.     After 7 weeks, patients who received RIMT training experienced a significantly larger FVC (p<0.001), a larger MVV (p<0.05), a higher PEF (p<0.01), a lower PImax (p<0.001), and a higher IC (p<0.05) compared to these measures after 1 week.

3.     After 7 weeks, patients who received AbWts training experienced a significantly larger FVC (p<0.001), a larger MVV (p<0.001), a higher PEF (p<0.001), and a lower PImax (p<0.001) compared to these measures after 1 week.

Raab et al. (2018)

Switzerland

Case Control

N=79

Population: Inspiratory Muscle Training Group – AIS A/B: Mean age: 48 yr; Gender: male=10, female=5; Level of injury: N/R; Injury severity: tetraplegia=7, paraplegia=8. Inspiratory Muscle Training Group – AIS C/D: Mean age: 63 yr; Gender: male=22, female=5; Level of injury: N/R; Injury severity: tetraplegia=22, paraplegia=5. Combined In- and Expiratory Muscle Training Group – AIS A/B: Mean age: 44.5 yr; Gender: male=14, female=2; Level of injury: N/R; Injury severity: tetraplegia=7, paraplegia=9. Combined In- and Expiratory Muscle Training Group – AIS C/D: Mean age: 60 yr; Gender: male=18, female=3; Level of injury: N/R; Injury severity: tetraplegia=18, paraplegia=3.

Intervention: Individuals had up to 5 training sessions per week of either inspiratory muscle training or combined in- and expiratory muscle training.

Outcome Measures: Maximal inspiratory pressure (PImax), expiratory pressure (PEmax), forced vital capacity, forced expiratory volume, sniff nasal inspiratory pressure, and peak expiratory flow. Results were stratified by AIS groups A/B and C/D.

Chronicity: On average patients were 2.4 mo post injury.

1.     PI max was seen to significantly increase for those treated with combined muscle training, regardless of AIS score (p<0.001) and for those treated with inspiratory muscle training only (p=0.008).

2.     PEmax was seen to significantly increase for those treated with combined muscle training, regardless of AIS score (p<0.001) and for those with AIS scores of C or D treated with inspiratory only muscle training (p<0.001).

3.     Forced vital capacity was seen to significantly increase in those who were treated with combined muscle training, regardless of AIS score (p<0.001). The same trends were observed for those in the inspiratory only muscle training groups (p<0.05).

4.      Forced expiratory volume was found to significantly increase in individuals treated with combined muscle training, regardless of AIS score (p<0.05), while the same trend was observed for those treated with inspiratory only muscle training (p<0.05).

5.     Sniff nasal inspiratory pressure was found to significantly increase in those treated with combined muscle training (p<0.001), regardless of AIS score. No significant improvements were observed in the inspiratory only muscle training group.

6.     Peak expiratory flow was only seen to improve significantly in the AIS C and D groups regardless of type of intervention (p<0.05), but not the AIS A/B groups.

 

 

 

 

Berney et al. (2002)

Australia

Case Control

N=14

 

 

 

 

Population: Mean age: 28 yr; Gender: male=11, female=3; Level of injury: C5-C7; Severity of injury: complete.

Intervention: Patients who received a tracheostomy were compared to patients who were extubated and received physiotherapy.

Outcome Measures: The following at the time of extubation/the day of tracheostomy: forced vital capacity (FVC), ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO2), total number of physiotherapy treatments, number of physiotherapy treatments in intensive care unit (ICU), length of stay in ICU, days requiring mechanical ventilation, length of stay in acute ward after discharge from ICU, days from injury to fixation.

Chronicity: Patients were studied beginning within 24 hr of injury.

1.     There was no significant difference in FVC between tracheostomized patients and physiotherapy patients (p>0.05).

2.     There was no significant difference in PaO2/FiO2 ratios between tracheostomized patients and physiotherapy patients (p>0.05).

3.     There was no significant difference in total number of physiotherapy treatments between tracheostomized patients and extubated patients. Patients who were extubated and received physiotherapy required significantly fewer treatments compared to tracheostomized patients in ICU (p=0.047).

4.     Tracheostomized patients spent significantly more days in ICU than physiotherapy patients (p=0.006) and required mechanical ventilation significantly longer than the physiotherapy group (p=0.018).

5.     There was no significant difference in the length of stay in the acute ward between groups (p>0.05).

6.     There was no significant difference in the time from injury to fixation between groups (p>0.05).

Discussion

Three RCTs have examined the effectiveness of physiotherapy techniques on the pulmonary function of patients with SCI. Postma et al. (2014) investigated the effect of RIMT in individuals with SCI during inpatient rehabilitation. This technique was found to have a positive short-term effect on inspiratory muscle function 1 week following the intervention period; however, this effect was no longer significant 8 weeks post muscle training. Two types of breathing exercise programs have been shown by one small RCT (Derrickson et al. 1992) to be effective at improving pulmonary function in patients with acute tetraplegia. Abdominal weights training and RIMT both appeared to be similar in efficacy and resulted in within-group improvements for all five (RIMT group) and four of five (abdominal weights training group) pulmonary function measures used in the study. Finally, Roth et al. (2010) assessed the effectiveness of expiratory muscle training compared to sham training in patients with SCI at an acute inpatient rehabilitation hospital. Multivariate analysis did not reveal any significant between-group differences for any pulmonary function tests conducted after the 6-week training period. A moderate sized case control study also found positive results with both inspiratory and combination in- and expiratory muscle training regardless of AIS score (Raab et al., 2018). It was found that measures of inspiratory and expiratory pressure significantly increased, as well as forced vital capacity regardless of muscle training group (Raab et al., 2018). Muscle training appears to be effective for improving respiratory parameters in acute SCI patients.

A case control study (Berney et al. 2002) has shown that extubation along with initiation of intensive physiotherapy can improve lung function, reduce the rate of pulmonary complications and decrease the length of stay in intensive care for patients with acute tetraplegia. It should be noted that both patients who have been extubated or who have had a tracheostomy are able to receive physiotherapy, as long as treatment occurs once the patient is in stable condition.

Physiotherapy treatments during acute SCI would be useful for stable patients and in hospitals that have the resources for on-call physiotherapists. Prospective large-scale RCTs should be conducted to confirm these preliminary findings that physiotherapy is an effective adjuvant to improve acute pulmonary functioning.

Conclusion

There is level 1b evidence (from two RCTs; Postma et al., 2014; Derrickson et al., 1992, and one case control study; Raab et al., 2018)) in support of inspiratory muscle training as an effective means to improve respiratory muscle function compared to usual care in acute SCI patients regardless of AIS status.

There is level 3 evidence (from one case control; Berney et al. 2002) that extubation and intensive physiotherapy reduces length of stay in intensive care in acute SCI patients.

  • Inspiratory and expiratory muscle training may improve respiratory muscle function during the acute phase post SCI. Length of stay in intensive care may be reduced by extubation in combination with intensive physiotherapy.