PT  - JOURNAL ARTICLE
AU  - L. Spicuzza
AU  - N. Casiraghi
AU  - A. Gamboa
AU  - C. Keyl
AU  - A. Schneider
AU  - A. Mori
AU  - F. Leon-Velarde
AU  - G.U. Di Maria
AU  - L. Bernardi
TI  - Sleep-related hypoxaemia and excessive erythrocytosis in Andean high-altitude natives
AID  - 10.1183/09031936.03.00000703
DP  - 2004 Jan 01
TA  - European Respiratory Journal
PG  - 41--46
VI  - 23
IP  - 1
4099  - http://erj.ersjournals.com/content/23/1/41.short
4100  - http://erj.ersjournals.com/content/23/1/41.full
SO  - Eur Respir J2004 Jan 01; 23
AB  - To determine whether nocturnal hypoxaemia contributes to the excessive erythrocytosis (EE) in Andean natives, standard polysomnographies were performed in 10 patients with EE and in 10 controls (mean haematocrit 76.6±1.3% and 54.4±0.8%, respectively) living at an altitude of 4,380 m. In addition, the effect of O2 administration for 1 h prior to sleep, and the relationship between the hypoxic/hypercapnic ventilatory response and the apnoea/hypopnoea index (AHI) during sleep were studied. Awake arterial oxygen saturation (Sa,O2) was significantly lower in patients with EEthan in controls (83.7±0.3% versus 85.6±0.4%). In both groups, the mean Sa,O2 significantly decreased during sleep (to 80.0±0.8% in EE and to 82.8±0.5% in controls). The mean Sa,O2 values remained significantly lower in patients with EE than in controls at all times of the night, and patients with EE spent significantly more time than the controls with an Sa,O2 of <80%. There were no differences between the two groups in the number and duration of the apnoeas/hypopnoeas. None of these variables were affected by O2 administration. In both groups the AHI positively correlated with the hypercapnic ventilatory response. Andean natives undergo minor respiratory disorders during sleep. The reduction inoxygen saturation found in subjects with excessive erythrocytosis was small, yet consistent and potentially important, as it remained below the threshold known for theincrease in erythropoietin stimulation. This may be an important factor promoting erythropoiesis, but its relevance needs to be further explored.