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Biomedical subjects

Ian E Smith

Publications and source records attributed to Ian E Smith.

38 records · Page 3Linked to original sources
PubMed2002

Domiciliary-assisted ventilation in patients with myotonic dystrophy.

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 treatment. DESIGN: Descriptive analysis of retrospective and prospective clinical data. SETTING: Inpatient, noninvasive respiratory-care unit in a tertiary referral center. 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: Results of arterial blood gas analysis showed a fall in mean PaCO(2) from 64.3 to 53.8 mm Hg (p < 0.05) on discharge after starting ventilation and a rise in mean PaO(2) 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 PaCO(2) of 52.4 mm Hg and PaO(2) 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 PCO(2) 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 patients. CONCLUSION: Use of domiciliary-assisted ventilation in patients with myotonic dystrophy is associated with prolonged survival and a sustained improvement in arterial blood gas tensions.

Blood Gas Analysis↗
PubMed2002

The effect of noninvasive intermittent positive-pressure ventilation during exercise in severe scoliosis.

STUDY OBJECTIVES: Noninvasive intermittent positive-pressure ventilation (NIPPV) may improve exercise performance in COPD patients. It is not known whether this also applies to other patient groups such as those with restrictive respiratory diseases. DESIGN: Randomized controlled trial. SETTING: Regional center for assisted ventilation. SUBJECTS: Eight patients with severe congenital scoliosis. INTERVENTIONS: A submaximal treadmill test was performed with NIPPV applied via a mouthpiece. Each subject performed three walks breathing with three different ventilators and one walk breathing through the mouthpiece alone in random order. In addition, four unencumbered walks breathing normally and without monitoring were performed. MEASUREMENTS AND RESULTS: The four unencumbered walks did not show a significant learning effect. The mean (SD) distance walked was 204 m (134.9 m). Using the mouthpiece alone, the walking distance fell to 140 m (75.8 m), and with the addition of the ventilators it fell further to 109 m (59.3 m). Grouped-effects analysis of variance showed this to be a significant difference in walking distance according to the type of walk (p = 0.048). There was no difference shown among the three brands of ventilator. At the breakpoint of exercise, significant increases were seen in tidal volume and minute volume (Mv) in the ventilator-assisted walks (p < 0.05) compared to walks performed breathing with the mouthpiece alone. CONCLUSIONS: Breathing via a mouthpiece impaired exercise performance, and there was no improvement when breathing with a ventilator, despite the observed increase in Mv. NIPPV has no beneficial effect on exercise endurance in patients with severe scoliosis.

Analysis of Variance↗