Background:
Increased frequency of chest infections in acute stroke patients may be the result of respiratory muscle weakness contributing to a weak cough and poor airway clearance. We undertook a systematic review of studies comparing respiratory muscle strength in acute stroke patients with age-matched controls.
Method:
A systematic review of literature was performed using the electronic databases Medline, EMBASE, ISI web of knowledge and the Scopus. The key words searched were
stroke
or
cerebrovascular accident
in combination with
cough,
inspiratory, expiratory
or
respiratory
and
strength
or
weakness.
Studies were included if they compared stroke patients with age matched controls and measured maximum inspiratory or expiratory mouth pressure (PImax and PEmax) for inspiratory and expiratory muscle strength respectively.
Results:
The initial search identified 136 articles, 14 of which remained after screening for pre-defined inclusion criteria and removal of duplicates. Eleven were excluded after reviewing abstracts (5 did not assess muscle strength, 5 did not include healthy control group, 1 absolute values could not be obtained). A further study was identified from the reference lists of screened articles. The 4 studies that met inclusion criteria included 121 subjects. Mean PImax ranged from 75-99 cmH
2
O in controls and 37-74 cmH
2
O in stroke patients. (mean difference 41 cmH
2
O, 95% CI 54 to 29 cm H
2
O; P<0.0001). Mean PEmax ranged from 52-89 cm H
2
O in stroke patients and was also reduced compared with age matched controls (mean difference 55 cmH
2
O, 95% CI 61 to 48 cmH
2
O; P<0.0001). (
Fig 1
).
Conclusion:
Individual studies and pooled data suggest that respiratory muscle strength is impaired in acute stroke patients. However, these studies are limited by small samples and design heterogeneity. Larger studies are needed to assess the relationship of respiratory muscle weakness with chest infections and clinical outcomes in the acute phase.
Inspiratory muscle training improves respiratory muscle strength, functional capacity and quality of life in patients with chronic kidney disease: a systematic review