Fontana G A, Pantaleo T, Lavorini F, Boddi V, Panuccio P
Dipartimento di Fisiopatologia Clinica, Istituto di Patologia Generale, Università di Firenze, Florence, Italy.
Eur Respir J. 1997 May;10(5):983-9. doi: 10.1183/09031936.97.10050983.
The assessment of cough threshold and intensity is important in respiratory medicine. We have developed a method for objectively and noninvasively assessing cough threshold and intensity of expiratory muscle efforts in response to inhalation of ultrasonically nebulized distilled water (UNDW). Thirty (83%) out of 36 volunteers studied coughed in response to UNDW inhalation. Cough threshold was taken as the lowest nebulizer output (mL x min(-1)) that induced cough in two challenges performed at a 30 min interval. At threshold level, repeatability of peak and slope of the integrated electromyographic (IEMG) activity of abdominal muscles was evaluated. Short- and long-term repeatability of cough threshold were evaluated in 15 subjects following a 3 h and a 6-9 month interval, respectively. Dose-response relationships between nebulizer outputs and IEMG-related variables were also investigated, as were the correlations between the latter and expiratory flow during voluntary coughing. The median (1st and 3rd quartile) cough threshold value was 0.89 (0.40 and 1.54) mL x min(-1). At threshold level, peak and slope of IEMG activity were highly reproducible. Cough threshold displayed a high degree of short- and long-term repeatability. Peak and slope of IEMG activity displayed a clear trend to increase (p<0.01) following inhalation of progressively higher UNDW outputs. Maximum flow during voluntary coughs of varying intensity correlated with the peak (p<0.05) and, more closely, with the slope (p<0.01) of abdominal IEMG activity. The assessment of cough threshold as well as the evaluation of the intensity of cough efforts by abdominal integrated electromyographic recordings may represent useful and reliable tools for cough research in humans.
咳嗽阈值和强度的评估在呼吸医学中很重要。我们已经开发出一种方法，用于客观、无创地评估在吸入超声雾化蒸馏水（UNDW）后呼气肌努力的咳嗽阈值和强度。在36名接受研究的志愿者中，有30名（83%）在吸入UNDW后出现咳嗽。咳嗽阈值被定义为在30分钟间隔内进行的两次激发试验中诱发咳嗽的最低雾化器输出量（mL×min⁻¹）。在阈值水平，评估了腹部肌肉综合肌电图（IEMG）活动峰值和斜率的重复性。分别在15名受试者间隔3小时和6 - 9个月后评估咳嗽阈值的短期和长期重复性。还研究了雾化器输出量与IEMG相关变量之间的剂量反应关系，以及后者与自主咳嗽时呼气流量之间的相关性。咳嗽阈值的中位数（第1和第3四分位数）为0.89（0.40和1.54）mL×min⁻¹。在阈值水平，IEMG活动的峰值和斜率具有高度可重复性。咳嗽阈值显示出高度的短期和长期重复性。随着UNDW输出量逐渐增加，IEMG活动的峰值和斜率呈现出明显的上升趋势（p<0.01）。不同强度自主咳嗽时的最大流量与腹部IEMG活动的峰值（p<0.05）相关，更密切地与斜率（p<0.01）相关。通过腹部综合肌电图记录评估咳嗽阈值以及咳嗽努力的强度，可能是人类咳嗽研究中有用且可靠的工具。
