Esophageal Doppler monitoring for hemodynamic assessment

This article reviews the importance of hemodynamic monitoring in adding to the clinical assessment of critically ill patients. The esophageal Doppler monitor (EDM) provides a less invasive way of obtaining hemodynamic information quickly and safely at the bedside. The concepts of Doppler signal acquisition and important nursing considerations are reviewed. Case studies are provided to understand how data from the EDM can impact patient care decisions at the bedside.     

24h食管pH监测和食管测压及奥美拉唑治疗试验在食管原性胸痛中的应用

目的 :探讨 2 4 h食管 p H监测和食管测压及奥美拉唑治疗试验在食管原性胸痛中的诊断价值。方法 :对食管原性胸痛 6 8例行内镜、食管测压、2 4 h食管 p H监测及 7d的奥美拉唑 (2 0 mg,2次 / d)治疗试验 ,治疗后症状评分比治疗前降低超过 75 %者则为治疗试验阳性。结果 :食管原性胸痛 6 8例中 5 5例 (81% )符合胃食管反流病 (GERD) ,胡桃夹食管 2例 ,早期贲门失驰缓症 3例 ,弥漫性食管痉挛 3例 ,无效食管运动 (IEM) 5例。GERD5 2例测压分析 ,35例(6 7% )符合 IEM诊断标准。奥美拉唑治疗试验对诊断 GERD的敏感性为 93% ,特异性为 85 %。结论 :GERD是食管原性胸痛的主要原因。 2 4 h食管 p H监测和食管测压是诊断食管原性胸痛的主要检查手段 ,奥美拉唑治疗试验是临床诊断GERD简便而实用的方法。     

Prolonged pH monitoring: Bravo capsule

The Bravo pH monitoring system is a safe and well-tolerated reliable method for measuring esophageal acid exposure. Key potential advantages of this system are related to its ability to be unobtrusive, comfortable, and provide study periods of longer duration. These advantages make it an excellent option for subjects who are unwilling or unable to tolerate conventional catheter pH monitoring. Whether the Bravo capsule improves diagnostic accuracy is still unclear; however, initial results are promising and further validation studies are expected. Whether this method is preferred over conventional monitoring for diagnostic evaluation depends on multiple considerations ranging from cost to possible contraindications for both systems. Further refinements in methodology and recording protocol are likely to be made, which will improve diagnostic accuracy and lower cost.     

Flexible pH sensor based on a conductive PANI membrane for pH monitoring

pH is a critical parameter used to specify the acidity or alkalinity of an aqueous solution in chemistry, food processing, and medical care. In this study, a conductimetric-type micro pH sensor has been achieved using PANI membrane fabricated on a flexible substrate film aiming to monitor wound healing. The sensor is based on the incorporation of a polyaniline (PANI) membrane, interdigital electrode, and polyimide (PI) substrate. PANI was doped with dodecyl benzene sulfonic acid (DBSA) to obtain good conductivity. The electrodes were patterned on the PI film by etching. The contact area between the PANI and interdigital electrodes improves the responsiveness of the pH sensor. A sensitivity of 58.57 mV per pH over the entire pH range from 5.45 to 8.62 was obtained experimentally, along with a superior repeatability of 8% FS (full scale) and a temperature drift of 6.8% FS. This micro flexible pH sensor aims to monitor the pH value of wound healing, which also facilitates the realization of online monitoring of the pH for telemedicine, food safety, and home health care.

A conductimetric flexible film pH sensor working in sensing materials of PANI membrane was developed for clinic wound monitoring.     

24小时食管pH监测和内镜检查在胃食管反流病的诊断价值

目的:本文旨在探讨食管pH监测和内镜检查在GERD中的诊断价值。方法:临床诊断GERD患者121例行内镜及pH检查,对照组18例行内镜和pH检查。结果:内镜食管炎检出率51.2％(74/121),pH检测,阳性率87.6％(106/121)。对74例内镜诊断的食管炎与pH检测进一步分析显示食管酸暴露时间越长,内镜下炎症程度及症状越重。而32例内镜阴性的症状性反流性食管炎,症状多为轻中度,pH<4的总时间％的值亦偏低,但其数值与食管酸暴露数值有重叠。故不能以内镜阳性作为诊断GERD的客观依据,必须结合使用其他方法才能回答有否反流。结论:24h pH确实是诊断GERD的比较理想的方法。     

Esophageal Doppler monitoring predicts fluid responsiveness in critically ill ventilated patients

Objective To test whether fluid responsiveness can be predicted by the respiratory variation in aortic blood flow and/or the flow time corrected for heart rate monitored with esophageal Doppler.Design and setting Prospective study in a 24-bed medical intensive care unit of a university hospital.Patients 38 mechanically ventilated patients with sinus rhythm and without spontaneous breathing activity in whom volume expansion was planned.Interventions The aortic blood flow was measured using an esophageal Doppler monitoring device before and after fluid infusion (500 ml NaCl 0.9% over 10 min). The variation in aortic blood flow over a respiratory cycle between its minimal and maximal values was calculated. The flow time was also measured.Measurements and results Aortic blood flow increased by at least 15% after volume expansion in 20 patients (defined as responders). Before fluid infusion the respiratory variation in aortic flow was higher in responders than in nonresponders (28±12% vs. 12±5%). It significantly decreased after volume expansion (18±11%) in responders only. A respiratory variation in aortic flow before volume expansion of at least 18% predicted fluid responsiveness with a sensitivity of 90% and a specificity of 94%. Flow time increased with fluid infusion in responders and nonresponders. A flow time corrected for heart rate below 277 ms predicted fluid responsiveness with a sensitivity of 55% and a specificity of 94%. The area under the ROC curve generated for variation in aortic blood flow ABF was greater than that generated for flow time.Conclusions The respiratory variation in aortic blood flow reliably predicts fluid responsiveness in patients with sinus rhythm and without breathing activity.     

GERD患者24h食管pH动态监测

目的　对 30例患有胃食管反流病 ( gastroesophagealrefluxdisease,GERD)的患者进行 2 4h食管动态pH值监测、探讨 2 4hpH值与胃食管反流 (GER)之间的关系 ,从而对GERD的发生、发展、预后提供科学依据。方法　 30例患者采用SynectisDigitrapperMKⅢ动态 pH监测仪及计算机分析用软件动态监测 2 4hpH值。采用Johson和DeMeester 6种参数指标对患者进行综合评分以反映病人的反流程度 ,通过症状指数的计算来比较有症状及无症状时食管反流 pH检测资料。 结果　 6种参数指标正常组分别为 ( 1.34± 1.10 ,1.6 0±1.2 4 ,1.10± 1.6 0 ,30 .0± 11.5 ,0 .75± 0 .2 0 ,6 .2± 5 .90 ) ,病例组分别为 ( 13.5 2± 8.4 7,12 .2 7± 4 .99,16 .94±4 .99,5 6 .2 4± 13.98,4 .12± 2 .4 8) ,两组经方差检验 ,差异显著 (P <0 .0 1)。病例组各参数诊断阳性率如下 :其中 pH <4的总时间阳性率为 90 % ,2 4h内pH <4超过 5min的反流次数阳性率为 80 % ,症状指数≥ 5 0 %的阳性率为 80 % ,总分 >14 .72的阳性率为 80 % ,立位 pH <4的总时间 %为 5 7% ,卧位 pH <4的总时间 %为87%。结论　我们认为pH <4的总时间 ( % )、pH <4长于 5min反流次数这二个参数指标结合症状指数及综合评分是判断GERD的重要指标。     

Limitations of urinary pH monitoring in long-term catheter users

Weekly measurement of urinary pH has become a standard part of long-term catheter management in many parts of the UK. The common problem of catheter encrustation is caused by urease-producing bacteria which also tend to produce alkaline urine. To determine if urinary pH changes in individual catheter users provided enough information for pH monitoring to aid in catheter management, an analysis of the literature was combined with a study of the urinary pH and catheter blockage patterns in 20 catheter users colonized with urease-producing bacteria. It was found that weekly pH measurement does not aid in the diagnosis or management of catheter encrustation. As such, this practice cannot be recommended.     

Use of intragastric pH monitoring in gastroesophageal reflux disease

Prolonged intragastric pH monitoring is a valuable technique for evaluating head-to-head comparisons of the antisecretory effects of different pharmacologic agents, for studying the effects of higher doses of proton pump inhibitors (PPIs) on daytime and nighttime pH control, for evaluating the effects of dose timing in relation to a meal on the intragastric pH response to these antisecretory agents, and for examining interindividual variability in individual pH response to PPIs taken orally. Measuring intragastric pH has helped immeasurably in understanding the efficacy of PPIs and is especially useful in the clinical arena to guide the management of patients across the spectrum of gastroesophageal reflux disease.     

Objective determination of pH thresholds in the analysis of 24 h ambulatory oesophageal pH monitoring

In 24 h oesophageal pH monitoring, pH 4 is widely but arbitrarily used as the threshold between reflux and non-reflux pH values. The aim of the study was to define pH thresholds objectively, based on Gaussian curve fitting of pH frequency distributions. Single-channel 24 h oesophageal pH monitoring was performed in 26 healthy volunteers and 26 patients with pathological gastro-oesophageal reflux, and five-channel pH-metry was performed in 14 healthy volunteers and 14 patients. The calculated pH thresholds varied between healthy volunteers from 5.0 to 6.4 in the upright position and from 4.5 to 5.7 in the supine position, but were constant between different oesophageal recording sites. In 15 and nine patients (single-channel and five-channel pH-metry respectively), pH thresholds could not be determined at the distal oesophageal sites. However, the calculated pH thresholds in the proximal oesophagus were in the same range as in the control subjects. The authors conclude that the use of the conventional threshold of pH 4 leads to underestimation of the extent of gastro-oesophageal reflux, but are reluctant to advocate the use of higher thresholds in clinical practice.     

Comparative Effects of Liquid Antacids on Esophageal and Gastric pH in Patients with Heartburn

This double-blind crossover trial compared the postmeal effects of single doses of liquid antacids on esophageal and gastric pH in patients with a history of heartburn. Treatment consisted of one of two antacids containing the same active components---aluminum and magnesium hydroxide---but different in vitro acid-neutralizing capacities (ANCs). The pH was assessed continually from 1 h before a refluxogenic meal to 4 h after its completion in 24 subjects who received 20 ml of Mylanta((R)) Double Strength (MYL-20: ANC = 101.6 mEq), 20 or 30 ml of Extra-Strength Maalox((R)) Plus (MA-20, MA-30: ANC = 116.2 and 174.3 mEq, respectively), or placebo (ANC = 0) in random order. Esophageal pH increased rapidly and significantly (p < 0.05) to peak values of 7.0--7.4 with antacid. The increase in mean esophageal pH values was significantly higher (p < 0.05) than placebo for 30 min with MA-20 and for at least 70 min with MYL-20 and MA-30. In contrast, gastric pH rose slowly to mean peaks of 2.9--3.1 with antacid. During this interval, only MYL-20 was associated with significant improvements (p < 0.05 versus placebo) in total number of reflux episodes and total time that esophageal pH measured >4. Thus, ANC alone is not a useful guide in predicting in vivo antacid behavior, as in this study where the antacid dose with the lowest ANC demonstrated a duration of action as long or longer than that of antacid doses with higher ANC values. The rapid, prolonged increases in esophageal pH that preceded modest changes in gastric pH strongly suggest that the lower esophagus is the primary site of antacid action for heartburn relief.     

Esophageal intraluminal pH recording in the assessment of gastroesophageal reflux and its consequences.

Intraluminal pH in the lower esophagus has been recorded during a 3-hr period following a ligh meal and a consecutive 12-hr nocturnal period in 20 patients with typical symptoms and radiological evidence of gastroesophageal reflux and in 10 patients without such signs of reflux. Evidence of acid reflux was obtained in 3 of the patients without reflux during the postcibal period but in only one during the 12-hr nocturnal period. In contrast all except one of the 20 patients who had evidence of reflux showed spells of high acidity both in the postcibal and nocturnal periods. There was no clear correlation between the frequency of paf high acidity in the nocturnal period. Those patients with endoscopic evidence of severe esophagitis showed a significantly longer duration of high esophageal acidity in the nocturnal period. We conclude that nocturnal exposure of the esophageal mucosa to acid is a major factor in the causation of reflux esophagitis.     

Importance of pH monitoring in the care of long-term catheters

One of the main complications encountered by patients with long-term in-dwelling catheters is that of catheter blockage as a result of encrustation. This is usually managed at a district nurse level by the administration of catheter maintenance solutions (CMSs) or frequent catheter changes. However, catheter changes and maintenance solutions are often only employed after blockage has occurred. Regular recording of catheter care and urinary pH monitoring can be utilized to optimize the management of long-term catheters and plan catheter changes and CMS administration in a prophylactic manner. This article reviews the literature regarding CMS and urinary pH and demonstrates how the introduction of continued and formalized recording of catheter care and pH monitoring can improve long-term catheter management.     

支气管哮喘患者24小时食管pH监测的分析

目的　许多研究发现支气管哮喘和胃食管酸反流有关 ,但是有关胃食管酸反流引起支气管哮喘的机制还并不是十分清楚 ,用 pH监测仪对支气管哮喘患者的胃食管酸反流进行监测 ,以进一步探讨哮喘病的发病机制。 方法　将 84例患者分为 3组 ,单纯反流组 (30例 ) ,哮喘组 (2 8例 ) ,哮喘伴反流组 (2 6例 )。应用敏感的 2 4小时食管 pH监测仪监测食管 pH的变化。 结果　伴有酸反流的哮喘患者的 2 4小时酸反流次数、超过 5分钟的反流次数和 pH <4的时间均明显高于无胃食管反流的支气管哮喘患者 ,但超过 5分钟的反流次数、最长反流时间和 pH <4的时间明显低于单纯有胃食管反流的患者。结论　伴有酸反流的支气管哮喘患者 ,其哮喘的发作与酸反流有密切的关系 ,但是其酸反流程度小于单纯有胃食管反流的患者。这说明此类患者的哮喘发作除与胃食管酸反流对食管下段的刺激有关外 ,对酸反应的高敏感性也是其发病的重要因素 ,因此与胃食管反流相关的支气管哮喘发作是这两方面作用的结果