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Food Ingestion as a Provocative Manometric Test for Esophageal Dysfunction
March 1989
CORRESPONDENCE
Table 1. Hydrogen Content of Some Commonly Used Sterilized Vacutainer Tubes
959
Food Ingestion as a Provocative Manometric Test for Esophageal Dysfunction
Hydrogen Vacutainer tube catalog No.
(vol/10 6 voW
6512 b 6432 b 6493 b 6526 b 6457 (EDTA) 6468 (Citrate) 6471 (Oxalate) 6483 (Heparin) 4960 (Polyanetholesulfonate)
2064-3072 672-768 61-73 104-112 316-492 344-384 471-502 432-520 1152-1248
EDTA, ethylenediaminetetraacetic acid. Siliconized tubes.
a
Range for three tubes.
b
Ionizing radiation is an effective method of sterilization but is destructive to organic compounds. One action of ionizing radiation on silicone polymers is to crosslink them; essential to this process is the splitting out of hydrogen, the chief volatile product of ionizing radiation. Additional products include methane, ethane, carbon dioxide, carbon monoxide, and water-soluble silanols (3). In ordinary open system use, the degradation products are probably innocuous, but in the unique case of the evacuated blood-collection tubes, the products may be a substantial source of interfering contaminants. Sterilization by ionizing radiation was not performed on a large scale until around 1978, so Niu's work was done before Hz contamination became a problem. Therefore, we have the feeling that storage of breath samples is not a commonplace use of evacuated blood-collection tubes, but should be limited to nonirradiated tubes. Consideration of the possible gaseous contamination caused by vacutainer storage of breath samples could be an important detail in precisely analyzing Hz. The presence of these unknown degradation products may also become an increasingly serious problem in the analysis of drugs, metabolites, and other substances of growing clinical interest. For example, due to a possible contamination of ultraviolet-absorbing compounds with serum separation tubes, a decreased tocopherol reading may occur with high-performance liquid chromatography assays Gens en WE, personal communication). We believe that there should be an alternative sterilizing method used by manufacturers to eliminate or minimize the possible important contamination of vacutainers. JIA JV ZHENG, M.D. IRWIN H. ROSENBERG, M.D.
Tufts University Boston, Massachusetts WESLEY JENSEN, Ph.D.
University of Chicago Chicago, Illinois 1. Ellis q, Kneip JM, Levitt MD. Storage of breath samples for Hz analyses. Gastroenterology 1988;94:822-4. 2. Niu HC, Schoeller DA, Klein PD. Improved gas chromatographic quantitation of breath hydrogen by normalization to respiratory carbon dioxide. J Lab Clin Med 1979;94:755-63. 3. Jensen WE, O'Donnell RT, Rosenberg IH. Gaseous contaminants in sterilized evacuated blood-collection tubes. Clin Chem 1982;28:1406.
Dear Sir: In a brief report by Allen et al. (1), the authors conclude that manometry performed with food ingestion rather than with water swallow should be used as a provocative test for esophageal dysfunction in anatomically normal esophageal patients with dysphagia. Thus, of 77 patients with a history of dysphagia only 6 (8%) experienced their dysphagia during water swallow, whereas 36 (47%) reported dysphagia during the test meal (p < 0.001). Furthermore, the manometric tracings that were normal during the water swallow now showed a motor abnormality associated with dysphagia. This interesting report appears to me to need further clarification. There is inadequate information as to why these patients were referred for study. In the clinical history did solids or liquids, or both, produce the dysphagia? Was a barium swallow performed especially with a bolus of food, e.g., bread or meat? Did the patients undergo endoscopy? The purpose of the latter two examinations is to rule out organic lesions as the cause, because dysphagia resulting from ingestion of food rather than water during the test suggests that the patients were suffering from an organic lesion rather than a motility disorder (2). Did any teche nique problems arise during this study as a consequence of administering a food bolus, i.e., plugging of the recording catheters thereby resulting in manometric artifacts? PHILIP KRAMER, M.D.
University Hospital Section of Gastroenterology SS East Newton Street Boston, Massachusetts 1. Allen AH, Orr WC, Mellow MH, et al. Water swallows versus food ingestion as manometric test for esophageal dysfunction. Gastroenterology 1988;95:831-3. 2. Kramer P. Dysphagia-etrologic differentiation and therapy. Hosp Pract 1988;233A:125-49. Reply. In response to Dr. Kramer's questions: we would very much have liked to have had the data that Dr. Kramer requests, in all patients. However, patients were referred to study by both gastroenterologists (all patients had esophagogastroduodenoscopies performed; in none were structural lesions found) and, in some instances, cardiologists and other internists. In that case, some, but not all, were subjected to endoscopic or radiographic esophageal evaluation, or both. Thus, it is not inconceivable that an occasional patient in this review had a structural lesion responsible for symptoms. One of the main thrusts of our report, however, is that standard esophageal motility testing has a very low sensitivity for the reproduction of dysphagia. This holds true even in patients with severe esophageal motility disorders, such as dmuse esophageal spasm and achalasia, in whom a history of dysphagia for liquids can be elicited. These patients rarely experienced dysphagia during standard esophageal testing (supine water swallows, small boluses, spaced 30 s apart) even though they would often complain of dysphagia during the upright food ingestion. Regarding catheter plugging, for example, our motility measurements were performed utilizing intraesophageal pressure transducers. Thus, catheter plugging was not a problem. One would occasionally see a very short "spike" recorded manome-
CORRESPONDENCE
Table 1. Hydrogen Content of Some Commonly Used Sterilized Vacutainer Tubes
959
Food Ingestion as a Provocative Manometric Test for Esophageal Dysfunction
Hydrogen Vacutainer tube catalog No.
(vol/10 6 voW
6512 b 6432 b 6493 b 6526 b 6457 (EDTA) 6468 (Citrate) 6471 (Oxalate) 6483 (Heparin) 4960 (Polyanetholesulfonate)
2064-3072 672-768 61-73 104-112 316-492 344-384 471-502 432-520 1152-1248
EDTA, ethylenediaminetetraacetic acid. Siliconized tubes.
a
Range for three tubes.
b
Ionizing radiation is an effective method of sterilization but is destructive to organic compounds. One action of ionizing radiation on silicone polymers is to crosslink them; essential to this process is the splitting out of hydrogen, the chief volatile product of ionizing radiation. Additional products include methane, ethane, carbon dioxide, carbon monoxide, and water-soluble silanols (3). In ordinary open system use, the degradation products are probably innocuous, but in the unique case of the evacuated blood-collection tubes, the products may be a substantial source of interfering contaminants. Sterilization by ionizing radiation was not performed on a large scale until around 1978, so Niu's work was done before Hz contamination became a problem. Therefore, we have the feeling that storage of breath samples is not a commonplace use of evacuated blood-collection tubes, but should be limited to nonirradiated tubes. Consideration of the possible gaseous contamination caused by vacutainer storage of breath samples could be an important detail in precisely analyzing Hz. The presence of these unknown degradation products may also become an increasingly serious problem in the analysis of drugs, metabolites, and other substances of growing clinical interest. For example, due to a possible contamination of ultraviolet-absorbing compounds with serum separation tubes, a decreased tocopherol reading may occur with high-performance liquid chromatography assays Gens en WE, personal communication). We believe that there should be an alternative sterilizing method used by manufacturers to eliminate or minimize the possible important contamination of vacutainers. JIA JV ZHENG, M.D. IRWIN H. ROSENBERG, M.D.
Tufts University Boston, Massachusetts WESLEY JENSEN, Ph.D.
University of Chicago Chicago, Illinois 1. Ellis q, Kneip JM, Levitt MD. Storage of breath samples for Hz analyses. Gastroenterology 1988;94:822-4. 2. Niu HC, Schoeller DA, Klein PD. Improved gas chromatographic quantitation of breath hydrogen by normalization to respiratory carbon dioxide. J Lab Clin Med 1979;94:755-63. 3. Jensen WE, O'Donnell RT, Rosenberg IH. Gaseous contaminants in sterilized evacuated blood-collection tubes. Clin Chem 1982;28:1406.
Dear Sir: In a brief report by Allen et al. (1), the authors conclude that manometry performed with food ingestion rather than with water swallow should be used as a provocative test for esophageal dysfunction in anatomically normal esophageal patients with dysphagia. Thus, of 77 patients with a history of dysphagia only 6 (8%) experienced their dysphagia during water swallow, whereas 36 (47%) reported dysphagia during the test meal (p < 0.001). Furthermore, the manometric tracings that were normal during the water swallow now showed a motor abnormality associated with dysphagia. This interesting report appears to me to need further clarification. There is inadequate information as to why these patients were referred for study. In the clinical history did solids or liquids, or both, produce the dysphagia? Was a barium swallow performed especially with a bolus of food, e.g., bread or meat? Did the patients undergo endoscopy? The purpose of the latter two examinations is to rule out organic lesions as the cause, because dysphagia resulting from ingestion of food rather than water during the test suggests that the patients were suffering from an organic lesion rather than a motility disorder (2). Did any teche nique problems arise during this study as a consequence of administering a food bolus, i.e., plugging of the recording catheters thereby resulting in manometric artifacts? PHILIP KRAMER, M.D.
University Hospital Section of Gastroenterology SS East Newton Street Boston, Massachusetts 1. Allen AH, Orr WC, Mellow MH, et al. Water swallows versus food ingestion as manometric test for esophageal dysfunction. Gastroenterology 1988;95:831-3. 2. Kramer P. Dysphagia-etrologic differentiation and therapy. Hosp Pract 1988;233A:125-49. Reply. In response to Dr. Kramer's questions: we would very much have liked to have had the data that Dr. Kramer requests, in all patients. However, patients were referred to study by both gastroenterologists (all patients had esophagogastroduodenoscopies performed; in none were structural lesions found) and, in some instances, cardiologists and other internists. In that case, some, but not all, were subjected to endoscopic or radiographic esophageal evaluation, or both. Thus, it is not inconceivable that an occasional patient in this review had a structural lesion responsible for symptoms. One of the main thrusts of our report, however, is that standard esophageal motility testing has a very low sensitivity for the reproduction of dysphagia. This holds true even in patients with severe esophageal motility disorders, such as dmuse esophageal spasm and achalasia, in whom a history of dysphagia for liquids can be elicited. These patients rarely experienced dysphagia during standard esophageal testing (supine water swallows, small boluses, spaced 30 s apart) even though they would often complain of dysphagia during the upright food ingestion. Regarding catheter plugging, for example, our motility measurements were performed utilizing intraesophageal pressure transducers. Thus, catheter plugging was not a problem. One would occasionally see a very short "spike" recorded manome-