Laryngographic investigation of postoperative hoarseness

This study investigates postoperative hoarseness by comparing the patient's subjective assessment of change in voice following intubation with objective measures made using the laryngograph. Twenty-five patients admitted for routine surgery were assessed pre- and postoperatively. An Fx histogram was recorded on the laryngograph. A linear analogue self-assessment scale was used to quantify hoarseness subjectively. The objective measure of hoarseness (spread or standard deviation of Fx histogram) correlated well with the patients' subjective assessment of hoarseness. Six patients showed a bi- or trimodal histogram following intubation. This is known to represent asymmetric muscular activity. It is concluded that change in voice following intubation correlates well with the measures of vocal fold trauma. These measures can be recorded as the change in spread, standard deviation of the Fx histogram. The transient postoperative hoarseness following intubation is due to laryngeal damage. This damage has 2 mechanisms; in most cases it is due to direct mucosal trauma but in other cases a deeper muscular damage occurs.