Addington W Robert, Stephens Robert E, Phelipa Michael M, Widdicombe John G, Ockey Robin R
Cough. 2008 Apr 30;4:2. doi: 10.1186/1745-9974-4-2.
Involuntary coughing such as that evoked from the larynx, the laryngeal cough reflex (LCR), triggers a coordinated contraction of the thoracic, abdominal and pelvic muscles, which increases intra-abdominal pressure (IAP), displaces the diaphragm upwards and generates the expiratory force for cough and airway clearance. Changes in the IAP during voluntary cough (VC) and the LCR can be measured via a pressure catheter in the bladder. This study evaluated the physiological characteristics of IAP generated during VC and the LCR including peak and mean pressures and calculations of the area under the curve (AUC) values during the time of the cough event or epoch.
Eleven female subjects between the ages of 18 and 75 underwent standard urodynamic assessment with placement of an intravesicular catheter with a fiberoptic strain gauge pressure transducer. The bladder was filled with 200 ml of sterile water and IAP recordings were obtained with VC and the induced reflex cough test (RCT) using nebulized inhaled 20% tartaric acid to induce the LCR. IAP values were used to calculate the area under the curve (AUC) by the numerical integration of intravesicular pressure over time (cm H2O.s).
The mean (+/- SEM) AUC values for VC and the LCR were 349.6 +/- 55.2 and 986.6 +/- 116.8 cm H2O.s (p < 0.01). The mean IAP values were 45.6 +/- 4.65 and 44.5 +/- 9.31 cm H2O (NS = .052), and the peak IAP values were 139.5 +/- 14.2 and 164.9 +/- 15.8 cm H2O (p = 0.07) for VC and LCR, respectively.
The induced LCR is the involuntary rapid and repeated synchronous expiratory muscle activation that causes and sustains an elevated IAP over time, sufficient for airway protection. VC and LCR have different neurophysiological functions. Quantification of the LCR using AUC values and mean or peak IAP values may be useful as a clinical tool for determining neurophysiological airway protection status and provide a quantitative assessment of changes in a patient's functional recovery or decline.
非自愿性咳嗽，如由喉部引发的咳嗽，即喉咳嗽反射（LCR），会触发胸肌、腹肌和盆底肌的协同收缩，从而增加腹内压（IAP），使膈肌向上移位，并产生咳嗽和气道清理所需的呼气力。在自主咳嗽（VC）和LCR过程中，IAP的变化可通过膀胱内的压力导管进行测量。本研究评估了VC和LCR过程中产生的IAP的生理特征，包括峰值和平均压力，以及咳嗽事件或时段内曲线下面积（AUC）值的计算。
11名年龄在18至75岁之间的女性受试者接受了标准尿动力学评估，通过放置带有光纤应变片压力传感器的膀胱内导管进行。膀胱内注入200毫升无菌水，并通过VC和使用雾化吸入20%酒石酸诱导LCR的诱导反射咳嗽试验（RCT）获得IAP记录。IAP值通过膀胱内压力随时间的数值积分（厘米水柱·秒）来计算曲线下面积（AUC）。
VC和LCR的平均（±标准误）AUC值分别为349.6±55.2和986.6±116.8厘米水柱·秒（p<0.01）。VC和LCR的平均IAP值分别为45.6±4.65和44.5±9.31厘米水柱（无显著性差异，p=0.052），峰值IAP值分别为139.5±14.2和164.9±15.8厘米水柱（p=0.07）。
诱导的LCR是一种非自愿性的快速且重复的同步呼气肌激活，会随着时间的推移导致并维持IAP升高，足以实现气道保护。VC和LCR具有不同的神经生理功能。使用AUC值以及平均或峰值IAP值对LCR进行量化，可能作为一种临床工具用于确定神经生理气道保护状态，并对患者功能恢复或衰退的变化提供定量评估。
