Pulmonary Manifestations of Systemic Disease: Systemic Disease |

Prolonged Duration of Sleep Apnea Events and Polycythemia for Highlanders at Sea Level FREE TO VIEW

Lu Tan, MD; Yun Li, PhD; Junying Zhou, PhD; Jihui Zhang, PhD; Rong Ren, PhD; Yun-Kwok Wing, PhD; Xiangdong Tang, PhD
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West China Hospital, Sichuan University, Chengdu, China

Copyright 2016, American College of Chest Physicians. All Rights Reserved.

Chest. 2016;149(4_S):A477. doi:10.1016/j.chest.2016.02.496
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SESSION TITLE: Systemic Disease

SESSION TYPE: Case Report Poster

PRESENTED ON: Sunday, April 17, 2016 at 11:45 AM - 12:45 PM

INTRODUCTION: There was limited understanding of the impact on obstructive sleep apnea (OSA) in highlanders and the accompanying changes when descending to lower altitude. A small-scale study showed that highlanders with OSA had an increased duration of OSA when descending to sea level.

CASE PRESENTATION: A 34-year-old male highlander living at 2200 meters altitude was hospitalized at West China Hospital, Chengdu. No specific findings were obtained except for polycythemia (hemoglobin 226 g/L). As heavy snoring and witnessed apneas, a standard in-lab polysomnography were performed. PSG showed apnea-hypopnea index (AHI) was 28.6/ h with a mean duration of 1.22 min. The longest OSA event was 6.3 min (Figure 1 A, B). An overnight continuous positive airway pressure (CPAP) titration was performed. His AHI reduced to 3.7/ h, with optimal pressure of 13 cm H2O. Ten days later after he returned to high altitude, an overnight at home PSG recording (Figure 1 C) showed that shorter duration of the longest (6.3 min to 3.5 min) and averaged (1.22 min to 0.8 min) OSA events, as well as higher AHI (28.6/ h to 60/ h) as compared to at sea level. The rest of follow-up examinations were carried out in West China Hospital. After one month CPAP therapy at high altitude, his headache and dizziness were completely remitted. At 2nd and 3rd month (Figure 1 D) follow-ups, overnight PSG recordings showed that the longest duration of OSA events were shortened to 3.8 and 3.5 min, and mean duration reduced to 0.9 and 0.82 min at sea level, respectively. This patient’s hemoglobin level was parallel decreased with shortened duration of the longest OSA events (Figure 1 E).

DISCUSSION: The finding is consistent with some previous studies, which suggested OSA highlanders had an increased duration of OSA events at sea level. Thus, the combination effects of decreased CO2 sensitivity and high level of hemoglobin may synergistically contribute to the extremely long OSA duration. In the current case, the remission of headache and dizziness symptoms was closely associated with a parallel reduction in hemoglobin after continuous CPAP therapy suggested OSA contributed to the development of polycythemia related headache and dizziness. As the improvement of recurrent intermittent hypoxia during sleep under continuous CPAP therapy, his hemoglobin level and the longest duration of OSA event at sea level progressively reduced. Clinically, the readily reversibility of the clinical symptoms, polycythemia and long OSA events upon CPAP therapy will suggest the heightened need to watch out for the occurrence of OSA among highlanders.

CONCLUSIONS: We hypothesized that the occurrence of OSA may compromise the adaptive hypoxic response mechanism in highlanders. The readily reversibility by CPAP will suggest the heightened clinical need to recognize the occurrence of OSA in highlanders.

Reference #1: Patz D, Spoon M, Corbin R et al. The effect of altitude descent on obstructive sleep apnea. Chest 2006;130 (6):1744-50.

DISCLOSURE: The following authors have nothing to disclose: Lu Tan, Yun Li, Junying Zhou, Jihui Zhang, Rong Ren, Yun-Kwok Wing, Xiangdong Tang

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