Transcutaneous PCO2 monitoring in the evaluation of hyperventilation of patients with recurrent nerve paralysis

Prevalence of perceived dysphonia in a geriatric population

OBJECTIVES

To characterize geriatric dysphonia, including its prevalence, quality-of-life impairment, and association with overall health status.

DESIGN

A validated survey-based study of geriatric dysphonia.

SETTING

An independent living facility for geriatric individuals.

PARTICIPANTS

The entire population of residents at the facility was offered the survey. The inclusion criterion was aged 65 and older.

MEASUREMENTS

Two survey-based measures were used to characterize dysphonia: a direct question asking whether participants had problems with their voice and a voice-related quality-of-life (V-RQOL) measure. In addition, participants were administered the 12-item Medical Outcomes Study Short Form survey, U.S. version 2.0, a concise survey designed to evaluate overall health status.

RESULTS

The prevalence of dysphonia was 20%. More than 50% of patients with voice problems incurred significant quality-of-life impairment resulting from their dysphonia as measured using V-RQOL scores. The mean total V-RQOL score+/-standard deviation was 89+/-20. Finally, general health measures did not reflect V-RQOL.

CONCLUSION

There is a high prevalence of voice problems in older people, with a large proportion having significantly impaired quality of life related to their dysphonia. General health measures do not reflect V-RQOL, and many individuals may wrongly attribute dysphonia to age-related change alone. Administration of validated instruments for assessing dysphonia is encouraged, because direct questions regarding voice difficulties may not be sensitive to the severity of vocal impairment.

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.

Influence of continuous speaking on ventilation

This study was conducted to explore the influence of speaking on ventilation. Twenty healthy young men were studied during periods of quiet breathing and prolonged speaking using noninvasive methods to measure chest wall surface motions and expired gas composition. Results indicated that all subjects ventilated more during speaking than during quiet breathing, usually by augmenting both tidal volume and breathing frequency. Ventilation did not change across repeated speaking trials. Quiet breathing was altered from its usual behavior following speaking, often for several minutes. Speaking-related increases in ventilation were found to be strongly correlated with lung volume expenditures per syllable. These findings have clinical implications for the respiratory care practitioner and the speech-language pathologist.