Effect of added dead space on sleep disordered breathing at high altitude.

OBJECTIVE: Sleep disordered breathing with central apnea or hypopnea frequently occurs at high altitude and is thought to be caused by a decrease in blood CO(2) level. The aim of this study was to assess the effects of added respiratory dead space on sleep disordered breathing. METHODS: Full polysomnographies were performed on 12 unacclimatized swiss mountaineers (11 males, 1 female, mean age 39 ± 12 y.o.) in Leh, Ladakh (3500 m). In random order, half of the night was spent with a 500 ml increase in dead space through a custom designed full face mask and the other half without it. RESULTS: Baseline data revealed two clearly distinct groups: one with severe sleep disordered breathing (n=5, AHI>30) and the other with moderate to no disordered breathing (n=7, AHI<30). DS markedly improved breathing in the first group (baseline vs DS): apnea hypopnea index (AHI) 70.3 ± 25.8 vs 29.4 ± 6.9 (p=0.013), oxygen desaturation index (ODI): 72.9 ± 24.1/h vs 42.5 ± 14.4 (p=0.031), whereas it had no significant effect in the second group or in the total population. Respiratory events were almost exclusively central apnea or hypopnea. Microarousal index, sleep efficiency, and sleep architecture remained unchanged with DS. A minor increase in mean PtcCO(2) (n=3) was observed with DS. CONCLUSION: A 500 ml increase in dead space through a fitted mask may improve nocturnal breathing in mountaineers with severe altitude-induced sleep disordered breathing.

Evaluation of the effects of L-acetylcarnitine on senile patients suffering from depression.

Twenty-eight patients aged between 70 and 80 years affected by depressive disturbance as defined by DSM III R (cat. 300.40) were subdivided at random into two homogeneous groups of 14 each. One group was treated with 500 mg three times a day of L-acetylcarnitine (LAC) in tablet form, while the other received placebo. Each patient was evaluated by the Hamilton Rating Scale for Depression, the Beck Depression Inventory, the Sandoz Clinical Assessment--Geriatric, and by clinical global impression. This investigation establishes that LAC is effective in counteracting symptoms of depression in the elderly. Relief of depressive symptomatology is expressed by decreased scores in the Hamilton Rating Scale for Depression and Beck Depression Inventory and by beneficial effects with regard to behavioural aspects.