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Biomedical subjects

A K Simonds

Publications and source records attributed to A K Simonds.

59 records · Page 4Linked to original sources
PubMed1986

Effects of protriptyline on sleep related disturbances of breathing in restrictive chest wall disease.

The effects of protriptyline on sleep stage distribution and gas exchange have been assessed in eight patients with nocturnal hypoventilation secondary to restrictive chest wall disease. At a dose of 10-20 mg taken when they retired the total sleeping time was unaltered but the proportion of rapid eye movement (REM) sleep fell from 22% to 12% (p less than 0.05). The total time spent at an arterial oxygen saturation of less than 80% decreased (p less than 0.01) and the magnitude of the fall correlated with the reduction in REM sleep (r = 0.67, p less than 0.05). There was also a reduction in the maximum carbon dioxide tension reached during the night (p less than 0.01). The arterial oxygen tension measured diurnally increased (p less than 0.05) from a median of 8.0 kPa (60 mm Hg) to 9.0 kPa (67.5 mm Hg), but the carbon dioxide tension and base excess were unchanged. Anticholinergic side effects were experienced by most patients but did not limit treatment.

Adult↗
PubMedDate not supplied

UK physicians' attitudes and practices in long-term non-invasive ventilation of Duchenne Muscular Dystrophy.

Previous studies have shown that long-term non-invasive ventilation (NIV) is not always routinely offered by all physicians in Duchenne Muscular Dystrophy (DMD), despite evidence that this treatment improves quality of life and survival. This study examined UK physicians' practices related to respiratory follow-up and DMD ventilation. A mailed questionnaire was used. Thirty-eight of the 59 (64%) UK physicians identified via the Muscular Dystrophy Campaign (MDC) responded. Eighty-one per cent of respondents felt ethically obliged to discuss NIV with families while 13% believed that NIV results in poor quality of life. Forty-seven per cent of physicians discuss in-depth the use of NIV when the patient is in respiratory failure. Eighty-four ventilated DMD patients in the respondents' practice use NIV (via Bi-Pap Nasal mask). Nearly 66% of physicians do not consider the public cost to be an impediment to offering NIV, despite significant problems with resources' allocation in their area. While the majority of UK physicians have comparable attitudes and practices regarding NIV, the questionnaire highlighted that not all specialists were aware of the existence of consensus guidelines regarding respiratory monitoring. In addition, different practices of disclosure of life-prolonging ventilation options were used by different physicians. Seventy-one per cent of physicians wished for national consensus guidelines for different DMD age groups.

Adult↗
PubMedDate not supplied

Effect of CO2 inhalation on central sleep apnea and arousals from sleep.

BACKGROUND: CO(2) inhalation reduces central sleep apnea (CSA) in patients with congestive heart failure (CHF) and idiopathic CSA. CO(2) is also a stimulus for cortical arousal, which has been linked to increased sympathetic nerve activity (SNA) and increased mortality in CHF patients with CSA. OBJECTIVE: We have tested the hypothesis that during sleep, inhalation of CO(2) sufficient to reduce the apnea-hypopnea index (AHI) would not reduce the arousal index (AroI). METHODS: In 10 male patients with CSA (7 with CHF and 3 with idiopathic CSA), the inspired CO(2) concentration was increased to raise the sleeping end-tidal CO(2) by 2-4 mm Hg during established stage 2 sleep. Each intervention was maintained for a 10-min period. Sleep stage was monitored with electroencephalograms, electrooculograms, submental electromyogram, airflow with pneumotachometer and respiratory effort and blood gases with oxygen saturation and end-tidal CO(2). During periods of air and CO(2) breathing, AHI and AroI were compared with paired t tests; patients acted as their own controls. RESULTS: Inhalation of CO(2) produced a significant reduction in AHI (mean +/- SEM) from 74.4 +/- 12.4 events/h during air breathing to 25.8 +/- 7.8 events/h with CO(2) inhalation (p = 0.002). However, the AroI was not significantly different between the two conditions, air 67.8 +/- 12.3 events/h and CO(2) inhalation 52.8 +/- 12.4 events/h (p = 0.264). CONCLUSION: CO(2) inhalation reverses CSA but not arousals from sleep. Our findings highlight the need for treatment options that reduce both respiratory events and decrease arousals from sleep, with their associated SNA sequelae.

Administration, Inhalation↗
PubMedDate not supplied

Nocturnal ventilation in neuromuscular disease--when and how?

While much evidence has been gained over the last decade to support the use of non-invasive ventilation (NIV) in a series of acute and chronic applications, some issues still need to be addressed, particularly regarding the timing of initiation of NIV and the best methods of implementation. This article discusses the role of NIV, if any, in preventing respiratory decline, as a physiotherapy adjunct, and in perioperative care for adults and children with neuromuscular disease.

Child↗