Abstract
Objective
To test the accuracy of colour-scaled indicator papers to measure pH values and to study the correlation between this method of measuring gastric juice pH once daily and 24-h continuous intragastric pH monitoring in intensive care patients.
Design
The accuracy of indicator papers was tested in the laboratory using colourless solutions and aspirated gastric juice and was then verified with a laboratory pH meter. Continuous intragastric pH monitoring was performed in mechanically ventilated ICU patients. Percentages of time with a pH value <3.0 and median pH values by 24-h continuous intragastric pH monitoring were compared to pH values measured once daily with indicator paper.
Setting
A mixed ICU.
Patients
A total of 150 measurements were taken by continuous pH monitoring in 91 mechanically ventilated ICU patients.
Measurements and results
The correlation between the pH measured with the indicator paper and subsequently verified with a laboratory pH meter in colourless solutions was 0.96 [regression coefficient (RC) 0.98, 95% confidence interval (CI) 0.91–1.05]. Measured in gastric juice it was 0.95 (RC 0.95, 95% CI 0.88–1.01). The correlation between median pH values, determined with 24-h continuous intragastric pH monitoring, and values measured with indicator papers was 0.39 (RC 0.43, 95% CI 0.26–0.59). The mean difference in pH, as determined by the analysis of Bland and Altman [22], was 0.9 with a SD of 4.7. The correlation between the percentage of time with pH<3.0, as obtained with continuous registration, and median gastric pH values (also obtained with continuous registration) was−0.94 (RC−0.06, 95% CI−0.06-−0.05); the correlation between the time and gastric pH values (measured with indicator paper) was−0.40 (RC−0.02, 95% CI−0.03-−0.02).
Conclusion
The colour-scaled indicator paper is an accurate method of measuring pH values, but there is a poor correlation between gastric pH values measured once daily and a total measurement derived from 24-h continuous intragastric pH monitoring. Changes in intragastric pH values cannot be accurately studied when measuring acidity once daily. The influence of various treatment regimens on intragastric acidity in relation to the development of gastric colonization and nosocomial pneumonia should be investigated either with continuous intragastric monitoring or with frequent measurements in aspirated gastric juice.
Similar content being viewed by others
References
Heyland D, Mandell LA (1992) Gastric colonization by gram-negative bacilli and nosocomial pneumonia in the intensive care unit patients: evidence for causation. Chest 101: 187–193
Tryba M (1991) The gastropulmonary route of infection-fact or fiction? Am J Med 91 [Suppl 2A]: 135–146
Du Moulin, Paterson DG, Hedley-White J, Libson A (1982) Aspiration of gastric bacteria in antacid-treated patients: a frequent cause of postoperative colonisation of the airway. Lancet: 242–245
Hillman KM, Riordan T, O'Farrel SM, Tabaqchal S (1982) Colonization of gastric contents in critically ill patients. Crit Care Med 10: 444–447
Garvey BM, McCambley JA, Tuxen DV (1989) Effects of gastric colonization on bacterial colonization in critically ill patients. Crit Care Med 17: 211–216
Driks MR, Craven DE, Celli BR, Manning M, Burke RA, Garvin GM, Kunches LM, Farber HW, Wedel SA, McCabe WR (1987) Nosocomial pneumonia in intubated patients given sucralfate as compared with antacids of histamine type 2 blockers. N Engl J Med 317: 1376–1382
Tryba M (1987) Risk of acute stress and nosocomial pneumonia in ventilated intensive care patients: sucralfate versus antacids. Am J Med 83 [Suppl 3B]: 117–124
Kappstein I, Schulgen G, Friedrich T, Hellinger P, Geiger K, Daschner FD (1991) Incidence of pneumonia in mechanically ventilated patients treated with sucralfate or cimetidine as prophylaxis for stress bleeding: bacterial colonization of the stomach. Am J Med 91 [Suppl 2A]: 125S-131S
Eddleston JM, Vohra A, Scott P, Tooth JA, Pearson RC, McCloy RF, Morton AK, Doran BH (1991) A comparison of the frequency of stress ulceration and secondary pneumonia in sucralfate- or ranitidine-treated intensive care patients. Crit Care Med 19: 1491–1496
Lee B, Chang RWS, Jacobs S (1990) Intermittent nasogastric feeding: a simple and effective method to reduce pneumonia among ventilated ICU patients. Clin Intensive Care 1: 100–102
Simms HH, DeMaria E, McDonald L, Peterson D, Robinson A, Burchard KW (1991) Role of gastric colonization in the development of pneumonia in critically ill trauma patients: results of a prospective randomized trial. J Trauma 31: 531–537
Prod'hom G, Leuenberger P, Koerfer J, Blum A, Chiolero R, Schaller MD, Perret C, Spinnler O, Blondel J, Siegrist H, Saghafi L, Blanc D, Francioli P (1994) Nosocomial pneumonia in mechanically ventilated patients receiving antacid, ranitidine, or sucralfate as prophylaxis for stress ulcer. Ann Intern Med 120: 653–662
Spilker CA, Hinthron DR, Pingleton SK (1993) Intermittent enteral feeding and gastric colonization in critically ill patients (abstract). Am Rev Respir Dis 147: A200
Heyland D, Bradley C, Mandell LA (1992) Effect of acidified enteral feedings on gastric colonization in the critically ill patient. Crit Care Med 20: 1388–1394
Caballero GA, Ausman RK, Quebbeman EJ, Schulte WJ, Lin L (1990) Gastric secretion pH measurement: what you see is not what you get! Crit Care Med 18: 396–399
Dobkin ED, Valcour A, McCloskey CR, Allen L, Kambe JC, Gleason E, Orlando R III, Berger R, Yeston NS (1990) Does pH paper accurately reflect gastric pH? Crit Care Med 18: 985–988
Levine RL, Fromm RE, Mojtahedzadeh M, Baghaie AA, Opekun AR (1994) Equivalence of litmus paper and intragastric pH probes for intragastric pH monitoring in the intensive care unit. Crit Care Med 22: 945–948
Fimmel CJ, Etienne A, Ciluffo T, et al (1985) Long-term ambulatory gastric pH monitoring: validation of a new method and effect of H2-antagonists. Gastroenterology 88: 1842–1851
Savarino V, Mela GS, Scalabrini P, Magnolia MR, Percario G, Di Timoteo E, Celle G (1987) 24-h Comparison between pH values of continuous intraluminal recording and simultaneous gastric aspiration. Scand J Gastroenterol 22: 135–140
Anderson J, Naesdal J, Ström (1988) Identical 24-hour gastric pH profiles when using intragastric antimony or glass electrodes or aspirated gastric juice. Scand J Gastroenterol 23: 375–379
Savarino V, Mela GS, Zentilin P, Magnolia MR, Scalabrini P, Valle F, Moretti M, Bonifacino G, Celle G (1989) Gastric aspiration versus antimony and glass pH electrodes. A simultaneous comparative in vivo study. Scand J Gastroenterol 24: 434–439
Bland JM, Altman DG (1986) Statistical methods for assessing agreement between two methods of elinical measurement. Lancet I: 307
Meiners D, Clift S, Kaminski D (1982) Evaluation of various techniques to monitor intragastric pH. Arch Surg 117: 288–291
Albin M, Friedlos J, Hillman K (1985) Continuous intragastric pH measurement in the eritically ill and treatment with parenteral ranitidine. Intensive Care Med 11: 295–299
Hastings PR, Skillman JJ, Bushnell LS, Silen W (1978) Antacid titration in the prevention of acute gastrointestinal bleeding. A controlled, randomized trial in 100 critically ill patients. N Engl J Med 298: 1041–1045
Priebe HJ, Skillman JJ, Bushnell LS, Long PC, Silen W (1980) Antacid versus cimetidine in preventing acute gastrointestinal bleeding. A randomized trial in 75 critically ill patients. N Engl J Med 302: 426–430
Author information
Authors and Affiliations
Additional information
This study was made possible by a grant (28-2125) from the Praevention Foundation
Rights and permissions
About this article
Cite this article
Bonten, M.J.M., Gaillard, C.A., Stockbrügger, R.W. et al. Assessment of gastric acidity in intensive care patients: Intermittent pH registration cannot replace continuous pH monitoring. Intensive Care Med 22, 220–225 (1996). https://doi.org/10.1007/BF01712240
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01712240