Study objectives: Respiratory failure is found in many
neuromuscular diseases, even when the lungs may be healthy, because of
an inadequacy of the ventilatory pump. Long-term domiciliary
ventilation is a well-established treatment in conditions such as
postpoliomyelitis; however, its use in patients with respiratory
failure secondary to myotonic dystrophy has not been well described.
The purpose of this study was to review the use of domiciliary-assisted
ventilation in these patients and to assess their response to
Design: Descriptive analysis of
retrospective and prospective clinical data.
Inpatient, noninvasive respiratory-care unit in a tertiary referral
Patients: Sixteen patients with myotonic
dystrophy, 13 of whom required ventilatory support.
Interventions and measurements: A retrospective study of
all patients with myotonic dystrophy referred for assessment for
assisted ventilation was performed, including results of arterial blood
gas analysis, pulmonary function tests, and overnight oxygen saturation
and transcutaneous carbon dioxide levels. A prospective reassessment of
all patients established on domiciliary ventilation was performed,
including measurements of quality of life.
Results of arterial blood gas analysis showed a fall in mean
Paco2 from 64.3 to 53.8 mm Hg (p < 0.05) on
discharge after starting ventilation and a rise in mean
Pao2 from 53.0 to 65.3 mm Hg (p < 0.05).
There were three deaths, at 5 months, 32 months, and 57 months,
respectively. The survivors received assisted ventilation for a mean
period of 27 months (range, 2 to 76 months). At reassessment,
improvements in arterial blood gas levels were maintained, with mean
Paco2 of 52.4 mm Hg and
Pao2 of 59.0 mm Hg. Mean overnight mean
arterial oxygen saturation rose from 80.5 to 90.3% after the start of
treatment (p < 0.001) and was maintained at 90.4% at reassessment.
Mean transcutaneous Pco2 during sleep fell from
59.3 to 41.4 mm Hg (p < 0.05), and to 43.7 mm Hg at reassessment.
There were no significant changes in spirometry or maximum mouth
pressures. Compliance with treatment for our test group was lower than
compliance in a group of age- and sex-matched postpoliomyelitis
Conclusion: Use of domiciliary-assisted
ventilation in patients with myotonic dystrophy is associated with
prolonged survival and a sustained improvement in arterial blood gas