Inspiratory muscle dysfunction after prolonged periods of mechanical ventilation; two case studies

Bruton, Anne, Conway, Joy H. and Holgate, Stephen T. (2002) Inspiratory muscle dysfunction after prolonged periods of mechanical ventilation; two case studies. Physiotherapy, 88, (3), 131 - 137. (doi:10.1016/S0031-9406(05)60546-9)

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Official URL: http://dx.doi.org/10.1016/S0031-9406(05)60546-9

Description/Abstract

Background and purpose

Mechanical ventilation necessitates periods of bed rest and relative immobility that, combined with other factors, lead to skeletal muscle atrophy. As the respiratory muscles are skeletal muscles, they are theoretically prone to disuse atrophy. Sustained maximal inspiratory pressure (SMIP) measures are a new form of assessment of inspiratory muscle function that may reflect inspiratory work capacity. The aim of this study was to establish whether inspiratory or peripheral muscle function is abnormal after a period of prolonged mechanical ventilation, and whether any changes in function occur during a prolonged weaning programme.

Methods

Two adult patients who had required mechanical ventilation on a general intensive care unit for more than 14 days consented to take part in the study. Baseline SMIP, standard maximal inspiratory pressure (MIP) and handgrip strength measures were performed when weaning began. Repeated SMIP, MIP and grip measures were taken twice a week during the weaning programme until each patient was able to breathe without support for 48 hours.

Findings

Baseline SMIP and handgrip measures were found to be abnormally low in both subjects. SMIP measures increased over a series of measurement sessions, in parallel with increases in measures of handgrip and diminishing levels of respiratory support. Standard MIP measures started from a level that would generally indicate ability to breathe without support and showed little change over time.

Conclusions

If SMIP is accepted as a reliable measure of inspiratory muscle function, then these findings support the hypothesis that periods of mechanical ventilation have a detrimental effect on respiratory muscle function. These findings also suggest that SMIP is responsive to changing inspiratory muscle function, but as they are from uncontrolled studies, no firm conclusions can be drawn.

Item Type:Article
Additional Information:Case study
ISSN:0031-9406 (print)
Uncontrolled Keywords:mechanical ventilation, intensive care, respiratory muscle
Related URLs:http://dx.doi.org/10.1016/S003...05)60546-9
Subjects:R Medicine > RM Therapeutics. Pharmacology
Divisions:University Structure - Pre August 2011 > Superseded (SOHPRS)
ePrint ID:17834
URI:http://eprints.soton.ac.uk/id/eprint/17834
Deposited On:16 Nov 2005
Last Modified:02 Mar 2012 13:04

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