經鼻連續性正壓呼吸面罩對阻塞性睡眠呼吸中止症患者其上呼吸道型態與功能影響之研究

Abstract

目的︰ 藉由動、靜態核磁共振影像來研究嚴重阻塞性睡眠呼吸中止症患者使用經鼻連續正壓呼吸面罩後，上呼吸道解剖解剖型態及功能是否有改變；並探討阻塞性睡眠呼吸中止症患者的上呼吸道型態及功能特徵及其與疾病嚴重性的關聯性。 材料和方法︰ 來自台大醫院的睡眠障礙門診的76位重度阻塞性睡眠呼吸中止症患者隨機分至實驗組（38位）及對照組（38位）分別使用有效的經鼻連續正壓呼吸面罩（n-CPAP）及壓力不足的n-CPAP三個月，之後比較兩組受測者接受不同n-CPAP的治療後上呼吸道型態及功能性的改變是否有差異，並比較所有受測者使用n-CPAP前上呼吸道氣道及側咽壁體積還有呼吸道截面積最大值、最小值、平均值及改變率（塌陷率）與疾病之相關性。 結果: 實驗組完成實驗者有35位，對照組完成者有27位，上呼吸道氣道完整體積及軟腭後呼吸氣道體積在有效n-CPAP治療後有增加的趨勢( p=0.034)；上呼吸道氣道完整體積與疾病相關性不明顯，但軟腭後呼吸道體積與CPAP理想壓力有相關（r=-0.314）；側咽壁的體積治療前後兩組的差異都不明顯，且與頸圍（r=0.456）及BMI（r=0.590）有相關性。呼吸道塌陷率在軟腭後治療前後改變兩組都不明顯，而舌頭後方呼吸道塌陷率在實驗組治療後有改善；呼吸道塌陷率在軟腭後方及舌頭後方的表現都與CPAP理想壓力有關。 結論: 三個月n-CPAP的治療對嚴重睡眠呼吸中止症患者上呼吸道側咽壁的體積沒有影響，但對軟腭後呼吸道氣道體積有增加的效果，表示此處呼吸道氣道體積的增加可能來自組織張力的增加；對舌頭後方呼吸道的動態塌陷程度有改善，但其機制為何及對疾病是否有助益需進一步研究。動態上呼吸道軸向截面積之最小值與上呼吸道阻力有一定程度的相關，研究如何降低此時塌陷的程度是未來可能發展的治療方向。

Objectives The narrowing of the upper airway caliber during sleep is believed to be essential to the pathogenesis of obstructive sleep apnea syndrome (OSAS). Nasal continuous positive airways pressure (nCPAP) is the therapy of choice especially for treating severe OSAS patients. We hypothesized that after continuous using of nCPAP, it could yield some persist changes of the upper airway. The aim of this study was to evaluate the changes of upper airway and its surrounding soft tissues of severe OSAS patients before and after nCPAP therapy. Material and method

76 severe OSAS patients were randomly assigned into two groups. In experimental group the patients have received nCPAP treatment with optimal pressure, i.e. effective nCPAP; and nCPAP with sub-therapeutic pressure, i.e. sham nCPAP, in control group. Static and dynamic MRI were used to image the upper airways in awakening supine posture of all subjects at baseline and 3 months after nCPAP therapy. The volume of the upper airway and the lateral pharyngeal wall were measured by using the serial static MRI. The area changes of the upper airway caliber sectioned at retro-palatal and retro-glossal levels were obtained from dynamic MRI to represent the collapsibility of the upper airway. The possible persist effects of nCPAP therapy on the upper airway were then analyzed by using these measurements.

Results 35 subjects in the experimental group and 27 subjects in the control group have completed all the measurements. The total and retro-palatal upper airway volume were significantly increased after using effective nCPAP, but not occurred in controls. The retro-palatal upper airway volume was also correlated with the optimal pressure of the nCPAP (r=0.314, p<0.05). The volume of the lateral pharyngeal wall was significantly correlated with neck circumference (r=0.456) and BMI (0.590); and the lateral pharyngeal volume seemed not to be changed after both effective and sham nCPAP treatments. By comparing the maximal, minimal, and mean area of the upper airway caliber, effective nCPAP treatment didn’t yield collapsibility change in the retro-palatal level but in the retro-glossal level. The collapsibility of the airway both in the retro-palatal and retro-glossal levels were significantly correlated with the optimal pressure of the nCPAP. Conclusion

In severe OSAS patients, the upper airway volume but not the lateral pharyngeal volume was increased after 3 months of effective nCPAP treatments. It seemed to indicate that such improvement might be due to strengthening of the tissue tone. The collapsibility of the upper airway in the retro-glossal level seemed to be also improved, but our study is not able to provide explanations. The upper airway resistance seemed to be correlated with the ratio between minimal and mean upper airway caliber. Its clinical implication needs future studies.