[Phrenic nerve conduction of obstructive sleep apnea-hypopnea syndrome patients].
OBJECTIVE
To investigate the significance of phrenic nerve conduction time (PNCT) and diaphragm compound muscle action potential (CMAP) detection in the assessment of severity and response to treatment in obstructive sleep apnea-hypopnea syndrome (OSAHS) patients.


METHODS
Sixteen healthy volunteers (control group), 8 primary snorers (snorer group), 14 mild-moderate OSAHS patients (mild-moderate group) and 18 severe OSAHS patients (severe group) were recruited for the study from January to July in 2005. Multi-pair esophageal electrodes were used to measure PNCT and CMAP of diaphragm in response to unilateral magnetic stimulation. The study was repeated in 5 OSAHS patients after effective nCPAP treatment for at least 2 months.


RESULTS
The PNCT in severe OSAHS group was (8.9 +/- 1.2), (7.9 +/- 1.5) ms respectively, which was significantly longer than those in the control group (6.5 +/- 0.7), (6.0 +/- 0.5) ms, snorer group (6.5 +/- 1.2), (6.0 +/- 0.8) ms and mild-moderate group (7.3 +/- 1.0), (6.3 +/- 0.7) ms. The amplitude of diaphragm CMAP was (1.4 +/- 0.4), (1.4 +/- 0.3) mV in mild-moderate group and (0.9 +/- 0.4), (1.1 +/- 0.6) mV in severe group, which was significantly lower than those in the control group (2.3 +/- 0.9), (2.1 +/- 0.9) mV and snorer group (1.9 +/- 0.5), (2.1 +/- 0.7) mV, and severe patients have significantly lower CMAP than mild-moderate patients. The PNCT and CMAP of both sides for all subjects correlated significantly with oxygen desaturation index and apnea-hypopnea index. The PNCT shortened significantly after effective nCPAP treatment, which was (8.6 +/- 0.6) ms, (7.4 +/- 0.5) ms for left side and (7.8 +/- 0.6) ms, (6.5 +/- 0.5) ms for right side.


CONCLUSIONS
PNCT and CMAP detection with multi-pair esophageal electrodes in response to unilateral magnetic stimulation may be useful for the severity assessment and evaluation of response to effective treatment in OSAHS patients.
Hou
Yu-hong
YH
Guangzhou Institute of Respiratory Disease, First Affiliated Hospital, Guangzhou Medical College, Guangzhou 510120, China.
Luo
Yuan-ming
YM
Li
Yin-huan
YH
Chen
Rong-chang
RC
D000200:Action Potentials; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction; D010791:Phrenic Nerve / Q000503:physiopathology*; D012121:Respiration, Artificial; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*