ESOPHAGEAL pH STUDIES IN ESOPHAGEAL DISEASE General Thoracic Surgery Chapter 119
Gastroesophageal reflux disease （ GERD ）• Continues to be a challenge to diagnosis.• Classic symptoms– Only 60 %-- Heart-burn and regurgitation.• Achalasia, cholelithiasis, gastritis, peptic ulcer, coronary artery disease – All mimic typical symptoms with GERD.
Gastroesophageal reflux disease （ GERD ）• The introduction of 24-hour esophageal pH monitoring provided a method to quantitate esophageal acid exposure.• Greatest sensitivity and specificity for diagnosis of gastroesophageal reflux – As the gold standard test.
Gastroesophageal reflux disease （ GERD ）• Three main cause of increase exposure of esophagus to refluxed gastric contents— (1) LES defective– Most. (2) Inefficient esophageal clearance as low peristaltic amplitudes or increase ineffective contractions. (3)Gastric abnormal– Decrease gastric empting.
Gastroesophageal reflux disease （ GERD ）• In early disease, the reflux episode occurred in upright position.• Bipositional reflux suggests more advanced disease and LES is severely impaired.• Pure supine reflux is rare.• Prolong reflux episodes suggest delayed esophageal clearance.
Bernstein test• Acid-perfusion test — Patient sitting with N-G tube 30 cm from nares, infusion normal saline 15 min, 0.1 N HCL at rate of 6 ml/min until symptoms produced.• The test is positive in two successive infusion periods acid induces pain and saline induces relief.• Specificity 89%, sensitivity is low because the pain induced by acid infusion does not correlate with the severity of esophagitis present.
Acid emptying test• Measeure the esophageal emptying capacity.• A bolus 15 ml of 0.1N HCl is introduced into esophagus 10 cm above the pH probe, patient repeat dry-swallows at 30-second intervals.• In normal– Distal esophagus is cleared of acid within 10 swallows.• Prolonged clearance test indicates an impaired capacity of the esophagus to clear the irritant material.• Lacks sensitivity.
24-hour esophageal pH monitoring• Importance of—to detect an increased esophageal exposure to refluxed acidic gastric contents.• patient with severe symptoms are found mild degree esophagitis in endoscope frequently.
24-hour esophageal pH monitoring• Mucosa injury was greatest in the exposure of pH 0-2.• Normal– The gastric pH is 1-2, esophageal pH 4-7.• Continuously measured esophageal pH below 4– Became the commonly used threshold of determing a reflux episode.
24-hour esophageal pH monitoring• False negative—duodenogastric reflux.• Alkaline secretions neutralize gastric acid.• If suspected, a probe measures bilirubin.• Food in stomach can also neutralized gastric acid.• Probe malfunction or misplacement.• Medication use-- particularly proton pump inhibitors.
Analysis of data• Analysis of pH tracing allowed calculation of the time that esophageal pH less than 4.• This value dose not reflect how the exposure occurred, fig 119-3.• It is necessary to know the number of times that esophageal drops below 4 and the duration of each episode.
Analysis of data• Esophagel pH can fluctuate just above and below 4 after a reflux episode fig 119-4.• Six components of 24-hour pH record, table 119-1,2.• Graphically displayed, fig 119-5.
Performance of the study• All medication affect the pH should be stopped.• PPI — 2 week.• H2-blocker — 2 day.• Antacid — 12 hour.• Promote gastrointestinal motility medication — 2 days.
Performance of the study• Keep accurate diary.• Document meal periods, any symptoms.• Only water is allowed between meal.• Eat normal-size meal.• Avoid much carbonated beverages – Because they have acidic pH and cause belching.
Performance of the study• Sleep only at night.• Avoid vigorous exercise.• Avoid alcohol drinking, cigarette smoking.
Performance of the study• Ideal probe to measure 24-hour pH—Small, firm, rapid response, minimally affect by temperature, no hysteresis effect, exhibit no drift, inexpensive, simple to calibrate, disposable or sterilizable – Not exist.• Two probes—glass or antimony, fig 119-6,• The probe should be calibrated in standard solutions at pH 1,4,7;
Performance of the study• Placement of probe — Proper positioning of pH electrodes requires prior manometry.• The probe must be placed 5 cm proximal to the upper border of LES, trans-nasally.
Esophageal pH monitoring in specific circumstances• Unexplained chest pain.• Recurrent pulmonary infection.• Adult-onset asthma.• Heartburn symptoms.
Unexplained chest pain• 10% GERD with chest pain as the only symptoms (esophageal claudication).• Exercise can induce reflux then exercise-induced chest pain.• 24-hour pH monitoring is more sensitive.• Ambulatory 24-hour esophageal manometry and pH monitoring.• Occurred in nutcracker esophagus or diffuse esophageal spasm.
Recurrent or persistent respiratory symptoms• Asthma, recurrent pneumonia especially in mid-lung field, severe bronchopulmonary disease in nonsmoker without obvious allergic triggers, onset bronchial asthma in late childhood or adult life.• Endoscopic esophagitis appear less common.
Recurrent or persistent respiratory symptoms• 45% of patient with reflux-induced respiratory disorder were found abnormalities in esophageal contractility
Achalasia• Some with heart-burn symptoms.• When regurgitate, they usually describe the material as bland tasting.• No significant reflux of gastric contents up into the esophagus.
Achalasia• 24-hour pH monitoring— Fermentation of retained food material in esophageal can produce a slow decline in esophageal pH to less than 4.• Distinguish between fermentation and reflux– The percentage of time that pH less than 3– Fermentation never produced a pH less than 3.
Bile• Duodenogastric reflux is rare.• Increase alkalinity in esophagus.• Cannot distinguish between the effect of swallowed saliva.• Second probe can positioned in stomach, acid reflux— Drop in esophageal pH less than 4 and gastric pH remain less than 4.
Mixed reflux• Esophageal pH decrease from 6 to 4-5 but gastric pH risen above 4.• Alkaline reflux – rise in esophageal pH above 7 and gastric pH greater than 4