Transcutaneous PCO(2) monitoring with hyperventilation during phonation in vocal cord paralysis.
OBJECTIVE
Hyperventilation during phonation is one of the causes of fatigue in-patients with vocal disorders.


METHODS
The transcutaneous (tc) PCO(2) during phonation in 8 normal subjects and 12 patients with unilateral vocal cord paralysis was measured. Cases were further divided into two groups by the degree of the tcPCO(2) decrease during phonation. Patients with a tcPCO(2) decrease less than 3.4 mmHg during phonation were classified as group 1 (G1). Patients with a tcPCO(2) decrease larger than or equal to 3.4 mmHg during phonation were classified into group 2 (G2).


RESULTS
The average changes in tcPCO(2) in the G1 cases was not significantly different from that in normal subjects. The decrease in tcPCO(2) during phonation in the six G2 cases was 10.7+/-6.2 mmHg, and was significantly different from that in normal subjects (P<0.01, t-test). The decrease of tcPCO(2) during phonation in both G1 and G2 cases improved significantly after surgical treatment. Easy fatigability during phonation in two G1 cases and five G2 cases improved.


CONCLUSIONS
The decrease in tcPCO(2) during phonation in cases of unilateral vocal cord paralysis is well correlated with easy fatigability. It is clinically useful to classify cases into two groups using the criteria of a less than 3.4 mmHg or larger than or equal to 3.4 mmHg decrease in tcPCO(2). These results also suggest that hyperventilation is one major cause for easy fatigability during phonation in cases with unilateral vocal cord paralysis. TcPCO(2) changes during phonation are useful in evaluating hyperventilation and the effect of treatment.
Miyazaki
Hiroshi
H
Department of Otorhinolaryngology, Faculty of Medicine, Kyushu University, 3-1-1 Maidashi, Higashiku, Fukuoka 812-8582, Japan. hmiyazak@ymg.urban.ne.jp
Umezaki
Toshiro
T
Yamashita
Hiroyuki
H
Yamamoto
Tomoya
T
Komiyama
Sohtaro
S
D000328:Adult; D000368:Aged; D001785:Blood Gas Monitoring, Transcutaneous; D005260:Female; D006801:Humans; D006985:Hyperventilation / Q000097:blood* / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D010699:Phonation / Q000502:physiology*; D012016:Reference Values; D013018:Sound Spectrography; D013061:Speech Acoustics; D014826:Vocal Cord Paralysis / Q000097:blood* / Q000175:diagnosis