ABSOLUTE PRESSURE MEASUREMENTS WITH HAND-DIPPED AND MANUFACTURED ESOPHAGEAL BALLOONS
ABSOLUTE PRESSURE MEASUREMENTS WITH HAND-DIPPED AND MANUFACTURED ESOPHAGEAL BALLOONS
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DOI：
10.1152/jappl.1974.37.4.600
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发表时间：
1974-01-01
影响因子：
3.3
通讯作者：
JONES, JG
中科院分区：
文献类型：
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作者：
LEMEN, R;BENSON, M;JONES, JG
方法：我们研究了18个食管球囊，每个长度为10 cm，这些球囊要么是新鲜手工浸渍的（4），要么是在美国市售的。这些球囊的压力-容积特性在空气中，垂直悬浮在水中，或定位在食管（体内）的同一个坐着的受试者（RJL）进行了研究。将球囊连接到聚乙烯管（PE-200，100 cm长）的末端，其中在球囊覆盖的管部分以5 mm间隔钻孔。用微卡尺在几个点测量球囊的厚度，并对每个球囊的结果取平均值。将管的另一端连接到带有17号钝针的应变计（斯坦森PM 13 1 TC）上。管和压力计的体积位移系数为0.002 ml/cm H2O。用快速书写照相记录器（DR-12 Electronics for Medicine，Inc.，纽约州白原）。在每次研究之前，以均匀的方式排空球囊。对于体外研究，将球囊放置在广口瓶中，球囊的下端系在放置在容器底部的10 g重物上。将广口瓶充入空气或水至气球顶部（图1）。将球囊在充满空气的广口瓶中压缩至50 cmH 2 O压力，同时将管路打开至大气压力。选择该排空压力代表Valsalva动作期间产生的压力。然后将球囊连接到应变仪上，释放罐压力。如果球囊弹性回缩引起的初始负压保持恒定2-3 min，则认为系统无泄漏。用玻璃结核菌素注射器向球囊中加入10 ml空气（大气压下0.05-0.5 ml），每次增量加入后记录压力。所有压力均参考大气压力，并绘制每个球囊的压力-体积曲线。对于水中的研究，首先以与空气研究所述相同的方式排空气球，然后将水添加到广口瓶中以刚好覆盖气球的顶部。将空气增量添加到球囊中，并以与空气中研究相同的方式构建压力-容积曲线。对于体内研究，将导管与大气相通的球囊经鼻插入胃中。按照Milic-Emili等人的建议，将其缓慢撤回，直到其位于食管中，其顶部距离受试者的鼻孔35 cm。（七）、通过对着关闭的百叶窗呼气至55 cmHz 0的口压来排空，然后连接到应变计。使用Milic-Emili等人的技术，针对增加到球囊的体积的每个增量产生肺压力-体积曲线。(7)但记录压力和体积随时间的变化（图2）。对于每个球囊体积重复该操作三次，并且使用每个肺体积的三个结果的平均值来构建压力体积曲线。根据Trop et al. (lo)我们测量了压力描记图上与心电图P波起始点一致的点的压力（图2）。如果记录压力中的心脏伪影以这种方式最小化，则每个肺体积处的经肺压力的重复测量变化小于1 cmHz 0：我们将绝对静态回缩压力定义为口腔压力减去外推到零球囊体积的食管压力（7，11）。比较了在每个球囊体积下获得的肺回缩压力容积曲线与通过外推压力至零球囊体积获得的回缩。
METHODSWe studied 18 esophageal balloons each 10 cm in length that were either freshly hand dipped(4) or commercially available in the United States. Pressure-volume characteristics of these balloons were studied in air, suspended vertically in water, or positioned in the esophagus(in vivo) of the same seated subject (RJL). Balloons were attached to the ends of polyethylene tubing (PE-200, 100 cm long) in which holes were drilled at 5-mm intervals in that portion of the tube covered by the balloon. The thickness of the balloon was measured with a microcaliper at several points, and the results were averaged for each balloon. The opposite end of the tubing was attached to a strain gauge (Statham PM 13 1TC) with a 17-gauge blunt needle. The volume displacement coefficient of the tubing and manometer was 0.002 ml/cmH20. Pressures were recorded with a rapid writing photographic recorder(DR-12 Electronics for Medicine, Inc., White Plains, NY). Prior to each study, balloons were emptied in a uniform manner. For in vitro studies, balloons were placed in a jar, the lower end of the balloon being tied to a 10-g weight resting on the bottom of the container. The jar was filled either with air or with water to the top of the balloon (Fig. 1). The balloon was compressed in the jar filled with air to 50 cmHzO pressure with the tubing opened to atmospheric pressure. This emptying pressure was chosen to represent the pressure produced during a Valsalva maneuver. The balloon was then connected to the strain gauge and the jar pressure released. The system was considered free of leaks if the initial negative pressure due to the balloon elastic recoil was maintained constant for 2-3 min. Volumes of air (0.05-0.5 ml at atmospheric pressure) were added to the balloon with a glass tuberculin syringe and the pressure was recorded after each incremental addition. All pressures were referred to atmospheric pressure, and pressure volume curves were drawn for each balloon. For studies in water, balloons were first emptied in the same manner as described for air studies, then water was added to the jar to just cover the top of the balloon. Increments of air were added to the balloon and the pressure-volume curve constructed in the same manner as for studies in air. For in vivo studies the balloon with the tubing open to the atmosphere was inserted transnasally into the stomach. It was slowly withdrawn until it lay in the esophagus with its top 35 cm from the subject’s nares as suggested by Milic-Emili et al.(7). It was emptied by expiring against a closed shutter to a mouth pressure of 55 cmHz0 and then connected to the strain gauge. Lung pressure-volume curves were produced for each increment of volume added to the balloon using the technique of Milic-Emili et al.(7) but recording pressure and volume against time (Fig. 2). The maneuver was repeated three times for each balloon volume and the mean of the three results at each lung volume was used to construct the pressure volume curves. Following the observations of Trop et al.(lo), we measured pressure at the point on the pressure tracing that coincided with the onset of the P wave of the electrocardiogram(Fig. 2). Repeated measurements of transpulmonary pressure at each lung volume varied less than 1 cmHz0 if cardiac artifacts in the recording pressure were minimized in this manner: We defined absolute static recoil pressure as the mouth pressure minus esophageal pressure extrapolated to zero balloon volume (7, 11). A comparison was made of the lung recoil pressurevolume curves obtained at each balloon volume with the recoil obtained by extrapolating pressures to zero balloon volume.