Skip Navigation LinksHome > September 1997 - Volume 87 - Issue 3 > Monitoring Gastric Mucosal Carbon Dioxide Pressure Using Gas...
Anesthesiology:
Clinical Investigations

Monitoring Gastric Mucosal Carbon Dioxide Pressure Using Gas Tonometry: In Vitro and in Vivo Validation Studies

Creteur, Jacques MD; De Backer, Daniel MD, PhD; Vincent, Jean-Louis MD, PhD

Free Access
Article Outline
Collapse Box

Author Information

Collapse Box

Abstract

Background: Saline gastric tonometry of carbon dioxide has been proposed as a means to assess the adequacy of splanchnic perfusion. However, this technique has several disadvantages, including the long time interval needed for gases to reach equilibrium in saline milieu. Thus the authors evaluated a system that uses a gas-filled instead of a saline-filled gastric balloon.
Methods: In vitro, we simultaneously placed two tonometry catheters in an equilibration water bath maintained at a predetermined and constant pressure of carbon dioxide (PCO2). The first catheter's balloon was filled with air and the second with saline. The performance of gas tonometry was tested by comparing the PCO2 measurements of the bath obtained via gas tonometry (PgCO2) to the PCO2 measurements of direct bath samples (PbathCO2). These results were also compared with the PCO2 measurements obtained simultaneously by saline tonometry (PsCO2). The response time of gas versus saline tonometry was also studied. In vivo, the performance of gas tonometry was tested comparing the measurements of gastric intramucosal PCO2 obtained by gas tonometry (PgCO2) at different equilibration times with those obtained by saline tonometry (PsCO2) using an equilibration time of 30 min. Two nasogastric tonometry catheters were placed simultaneously in seven stable patients in the intensive care unit. The first balloon was filled with air and the second with saline.
Results: In vitro, there was a close correlation between PgCO sub 2 and PbathCO2, for each level of PbathCO2, and for each different gas equilibration time. For an equilibration time of 10 min at a PbathCO2 level of approximately 40 mmHg, the bias of the gas device defined as the mean of the differences between Pbath sub CO2 and PgCO2, and its precision defined as the standard deviation of the bias, were -0.3 mmHg and 0.7 mmHg, respectively. Using the same definitions, the bias and precision of saline tonometry were 11.2 mmHg and 1.4 mmHg, respectively. If the equilibration time-dependent correction factor provided by the catheter manufacturer for saline tonometry was applied, the bias and precision were -6.9 mmHg and 2.9 mmHg, respectively. In vivo, using an equilibration time of 10 min for gas and 30 min for saline tonometry, there was a close correlation between the two techniques (r2 = 0.986). A Bland and Altman analysis revealed a bias (+/- 2 SD) of 0.1 +/- 6.8 mmHg. The correlation between the two methods was not improved if we prolonged the equilibration time of the gas tonometer.
Conclusions: Gas tonometry is comparable to saline tonometry for measuring gastric intramucosal PCO2. Because gas tonometry is easier to automate, it may offer advantages over saline tonometry.
Monitoring gastric mucosal pressure of carbon dioxide (PCO2) by gastric tonometry has been proposed to assess the adequacy of splanchnic perfusion. The technique first described by Fiddian-Green et al. [1] and by Grum et al. [2] included a saline-filled gas-permeable balloon placed in the gastric lumen. After a defined time interval (typically 30 min or longer), allowing equilibration of the saline solution with the gut intraluminal PCO2, the sample is aspirated for PCO2 determination using a conventional blood gas analyzer. Several problems have been associated with this procedure, including an important variability in the determination of saline PCO2 depending on the type of blood gas analyzer used, the long time interval needed for gas to reach equilibrium in saline milieu, and errors introduced by saline solution manipulations.
Assuming free and rapid carbon dioxide diffusion between the gastric mucosa and the lumen, the equilibration time could be shorter if the catheter balloon is filled with air rather than saline. These theoretical considerations regarding gas diffusion suggest that a gas-filled balloon may offer advantages over a fluid-filled one. A recent study by Guzman and Kruse [3] compared a capnometric recirculating gas tonometry system to saline tonometry in vitro using an equilibration chamber and in vivo in anesthetized dogs. The data indicated that continuous monitoring of gastric intramucosal PCO sub 2 by gas tonometry was feasible and had a short equilibration time.
This study validated gas tonometry in vitro and in vivo and compared its performance to measurements using saline tonometry.
Back to Top | Article Outline
Methods
In Vitro Studies
We used a metal container filled with 150 ml distilled water as an equilibration chamber to perform in vitro tonometry. The gas source was provided by a mixture of nitrogen and carbon dioxide, introduced into the chamber at a nominal flow rate of 5 l/min. We adjusted the gas mixture to maintain the PCO2 of the bath (PbathCO2) at approximately 40 mmHg or 80 mmHg, as desired. The container was placed in a larger water bath maintained at a constant temperature of 37 [degree sign] Celsius.
A first standard tonometry nasogastric tube equipped with a semipermeable Silastic balloon (TRIP, NGS catheter; Tonometrics, Helsinki, Finland) was placed in the bath and connected to an automated gas analyzer (Tonocap; Datex, Helsinki, Finland). This system pumps room air into the balloon and aspirates the sample after a predefined equilibration time of 10, 15, 30, or 60 min. The PCO2 in the aspirated air is measured by an infrared sensor. With each measurement cycle, 8 ml air is inflated into the balloon and aspirated after a set time. The first 2 ml of the sample is discarded, because this corresponds to the dead space of the system (including catheter, connecting tube, and tube in the Tonocap analyzer). The PCO2 is measured in the final 6 ml of aspirate. Thirty seconds later the balloon is reinflated with the same 8-ml sample and a new measurement is obtained. The entire sequence of inflation, aspiration, PCO2 measurement and reinflation is fully automated.
A second standard tonometry nasogastric tube was plunged into the bath, but this time it was filled with saline. It was prepared according to the manufacturer's instructions and filled with 2.5 ml saline solution. After a predetermined equilibration time, 1 ml of dead space volume was aspirated from the catheter and discarded. The remaining saline solution was then aspirated and analyzed for PCO sub 2 (ABL 500; Radiometer, Copenhagen, Denmark).
We first studied the effect of changes in equilibration times on the PCO2 measurements obtained by the saline and the gas techniques. We stabilized the PbathCO2 at about 40 mmHg and altered the equilibration times as follows: for each measurement technique, three gas PCO2 measures were obtained with an equilibration time of 10 min, followed by six measures with an equilibration time of 15 min, two with an equilibration time of 30 min, and two with an equilibration time of 60 min. The equilibration times were then progressively decreased in a similar manner: two measures with an equilibration time of 30 min, six with an equilibration time of 15 min, and three with an equilibration time of 10 min. The entire procedure lasted 8 h. The next day the process was repeated for a Pbath sub CO2 of 80 mmHg using the same tonometry catheters. The gas measurements were fully automated, with the operator needing to alter only the equilibration time of the gas device. The saline tonometry measurements were performed with the tonometry catheter in place, with only emptying and refilling the balloon with saline solution. Thus 24 measures for each level of PbathCO2 and for each measurement technique were recorded. Every 30 min, the PbathCO2 was checked by analysis of a sample of bath water (Radiometer ABL 500 gas analyzer), and this value was used as the reference for the saline and gas PCO2 measurements obtained during the preceding 30 min. These in vitro manipulations were performed five times using a new pair of catheters for each manipulation.
The biases of the automated gas analyzer and the saline tonometer were defined as the mean of the differences between PbathCO2 and PgCO2, and between PbathCO2 and PsCO2, respectively. The precision is the standard deviation of the bias. Data are expressed as mean +/- SD.
Using an identical in vitro system, we compared the response times of gas and saline tonometry during acute changes in PbathCO sub 2. After ensuring that the PbathCO2 was stable at about 40 mmHg, we abruptly increased PbathCO2 to approximately 80 mmHg by altering the gas mixture. During the next 5 min, the PbathCO2 was determined every minute by analyzing a direct sample of bath water (Radiometer ABL 500 gas analyzer). We used the shortest equilibration time of the gas analyzer that was provided by the manufacturer (10 min) and the same equilibration time for the saline tonometer. We repeated these measurements after an abrupt decrease of the PbathCO2 from 80 to 40 mmHg. We did the entire procedure five times. The response time was defined as the time needed to reach 95% of the change in PCO2, for an abrupt change in PbathCO2.
For this in vitro part of the study, we first used uncorrected raw PCO2 measures obtained by the saline tonometry. Then we corrected these PCO2 measures by multiplying the raw PCO2 values by the correction factors provided by the catheter manufacturer, which depend on the length of time the saline solution remains in the tonometer balloon (correction factor 1.62 for equilibration time of 10 min; 1.44 for 15 min; 1.24 for 30 min; 1.13 for 60 min). We also calculated our own in vitro saline tonometer correction factors for each equilibration time by dividing the mean PbathCO2 value by the corresponding mean PsCO2 value obtained at the corresponding equilibration time. We finally compared our correction factors to the manufacturer's values.
Back to Top | Article Outline
In Vivo Studies
After obtaining approval of the ethics committee of Erasme University Hospital, two nasogastric tonometry catheters (Tonometrics) were inserted together in seven sedated, mechanically ventilated, and hemodynamically stable critically ill patients during a study period of 6 h. Three patients had septic shock due to cerebral abscess (n = 1) or bronchopneumonia (n = 2), two patients had acute respiratory distress syndrome due to peritonitis (n = 1) and pulmonary graft rejection (n = 1), and two patients had intracerebral bleeding. There were five men and two women aged 42-80 yr (mean, 62 +/- 13 yr). All patients were mechanically ventilated, sedated (with midazolam and morphine), and paralyzed with pancuronium. All patients were invasively monitored with a pulmonary artery catheter (Swan Ganz catheter 93A-131-7F; Baxter Healthcare, Irvine, CA) and an arterial catheter. Every 30 min throughout the study, thermodilution cardiac output was measured (computer 9520 A, Baxter Healthcare) by successive injections of at least five boluses of 10 ml cold (< 8 [degree sign] Celsius) 5% dextrose in water, via a closed system (CO-set system, Baxter Healthcare). Each patient had been treated with H2 receptor blockers (150 mg ranitidine given intravenously each day), with no enteral feeding for at least the previous 6 h. In each patient, the position of the two nasogastric catheters was checked radiographically.
The first catheter, dedicated to saline tonometry, was prepared according to the manufacturer's instructions and filled with 2.5 ml saline solution. After an equilibration time of 30 min, 1 ml dead space volume was aspirated from the catheter and discarded. The remaining saline solution was aspirated and analyzed for PCO2 (Radiometer ABL 500 gas analyzer). The adjusted saline PCO2 (PsCO2) was obtained by multiplying the measured PCO2 by the correction factor obtained in our in vitro study for an equilibration time of 30 min.
The second catheter, dedicated to gas tonometry, was connected to an automated gas analyzer (Tonocap, Datex). After balloon filling with air in a closed circuit (see previous), the gas PCO sub 2 (PgCO2) was automatically measured by infrared spectroscopy after pre-established equilibration times of 10, 15, or 30 min.
In each patient, 24 PgCO2 measures were performed successively, in the following order: six measures with an equilibration time of 10 min, four measures with an equilibration time of 15 min, four with an equilibration time of 30 min, four with an equilibration time of 15 min, an six with an equilibrationd time of 10 min. The PgCO2 values obtained during a period of 30 min were compared with the simultaneous PsCO2 value obtained after the same 30 min of equilibration.
The effects of acute changes in PaCO2 on PgCO sub 2 were also studied in one sedated, paralyzed, and mechanically ventilated patient with acute respiratory failure as part of the study of respiratory mechanics under a FIO2 of 100%. The gastric mucosal PCO2 was measured by saline tonometry (PsCO2) with an equilibration time of 30 min and by gas tonometry (PgCO sub 2) with an equilibration time of 10 min, and the arterial pressure of carbon dioxide (PaCO2) was measured every 10 min using a blood gas analyzer (Radiometer ABL 500).
Statistical evaluation included linear regression and a Bland and Altman analysis. [4]
Back to Top | Article Outline
Results
In Vitro Studies
The PbathCO2 remained stable during all the studies at 40.2 +/- 0.7 mmHg (lower level) and 76.4 +/- 0.8 mmHg (higher level), respectively. There was a close correlation between PbathCO2 and PgCO2 values for each level of PbathCO2 and for each gas equilibration time. For the lower level of PbathCO2 and for an equilibration time of 10 min, the bias and the precision of the gas tonometer were -0.3 mmHg and 0.7 mmHg, respectively. Table 1 shows the bias and precision for the two PbathCO2 levels and different equilibration times. Increasing the equilibration time of the gas analyzer did not improve the precision or decrease the bias of the PgCO2 measurements.
Table 1
Table 1
Image Tools
(Table 2) shows the in vitro bias and precision of saline tonometry using raw uncorrected PCO2 values in the same conditions. For the lower level of PbathCO2 and for an equilibration time of 10 min, the bias and the precision of the saline tonometer were 11.2 mmHg and 1.4 mmHg, respectively. The bias was greater for saline than for gas tonometry, especially for short equilibration times (10 and 15 min). Table 2 also shows the in vitro bias and precision of saline tonometry in the same conditions, but after correction of the saline PCO2 measurements by the correcting factor provided by the catheter's manufacturer. Our own saline tonometer correction factors, extrapolated from the in vitro study, are shown and compared with the manufacturer's data in Table 3.
Table 2
Table 2
Image Tools
Table 3
Table 3
Image Tools
Acute changes in PbathCO2 were achieved in less than 3 min. In this situation, PgCO2 obtained after an equilibration time of 10 min was closer to the final steady-state Pbath sub CO2 than the PsCO2 but neither reached 95% of the change in PCO2 (Table 4). Reaching this value required two periods of 10-min equilibration time with both techniques.
Table 4
Table 4
Image Tools
Back to Top | Article Outline
In Vivo Studies
All patients were hemodynamically stable and had no cardiac output changes greater than 5% during the study. There was a close correlation between PgCO2 and PsCO2 for each gas equilibration time, with the following regression coefficients: equilibration time of 10 min, r2 = 0.986 (Figure 1); 15 min, r sup 2 = 0.967; 30 min, r2 = 0.946. A Bland and Altman analysis was performed for each gas tonometry equilibration time. The bias (+/- 2 SD) was 0.1 +/- 6.8 mmHg for an equilibration time of 10 min (Figure 2), -2.1 +/- 11.4 mmHg for an equilibration time of 15 min, and -5.1 +/- 11.4 mmHg for an equilibration time of 30 min.
Figure 1
Figure 1
Image Tools
Figure 2
Figure 2
Image Tools
When each patient was included only once, analyzing only the PgCO2 value obtained at the end of the equilibration time for the PsCO2, the correlation coefficients were similar (r2 = 0.992, data not shown).
In the patient in whom hypercapnia developed acutely, there was a close correlation between PaCO2, PsCO2, and Pg sub CO2 (Figure 3).
Figure 3
Figure 3
Image Tools
Back to Top | Article Outline
Discussion
First our study demonstrates first that in vitro PCO2 measurements obtained by gas tonometry are reliable. Second, due to the rapid carbon dioxide diffusion in gas, these measurements do not require an equilibration time of more than 10 min. In fact, the accuracy of gas tonometry was not greater with prolonged equilibration times. The great bias between the in vitro PbathCO2 value and the saline tonometry PCO2 measurements, especially for short equilibration times (10 and 15 min), is due to the incomplete equilibration of saline solution with environmental PCO2 after these short equilibration times. Factors have been developed in in vitro and in vivo studies to correct for this incomplete equilibration if the measurement time, as applied in many studies, is much shorter (+/- 30 min) than the complete equilibration time. In vitro saline tonometry biases remained greater than those of gas tonometry, even after correction of raw saline PCO2 values by the manufacturer's correction factors. This difference may be due to the correction factor recommended by the manufacturer. This measurement bias for short equilibration times may be clinically compromising if we consider that a normal PCO2 gap value, as defined by the difference between gastric mucosal PCO2 and arterial PCO2, is less than 6 mmHg. We derived our own scale of correction factors from the in vitro study and obtained values that were different from those of the manufacturer, especially for short equilibration times. The differences between our correction factors and the manufacturer's values could be due to use of different blood gas analyzers. Therefore, use of such a correction factor can amplify the PCO2 measurement error. Equilibration times of less than 30 min, which need the greatest correction factors, therefore cannot be recommended for saline tonometry. The in vivo study shows that PCO2 measurements by gas tonometry correlate well with those obtained by saline tonometry and again do not require an equilibration time of more than 10 min. In a recent study in pigs, Knichwitz et al. [5] described a fiberoptic P sub CO2 sensor that can determine intramucosal gut PCO2 in a precise and reliable manner. Their in vitro study indicated that the response time of their PCO2 sensor was identical to our gas device.
The major advantage of gas tonometry is that balloon filling with air rather than saline allows a fully automated procedure that avoids saline manipulations, which are time consuming and potential sources of error. The proper interpretation of PgCO2 requires the recognition of two important principles. First, PgCO2 is directly influenced by PaCO2, so that changes in ventilatory status can alter PgCO2 in the absence of any change in regional blood flow. This observation was made in 1959 when a group of Hungarian physicians proposed the measurement of gastric PCO2 in lieu of arterial PCO2 during mechanical ventilation. [6] Similar observations were reported more recently in animals. [7] We had the opportunity to document an excellent correlation between PaCO2 and PsCO2 or PgCO2 in one patient in whom transient hypercapnia developed (Figure 3). Thus one should always use the PCO2 gap (the PgCO2 - PaCO2 difference) when assessing gastric oxygenation. This is not an additional constraint, because pHi measurement should be considered in relation to arterial pH to avoid the influence of metabolic acidosis. [8] The use of capnometry in patients with a stable dead space ratio may be very valuable, especially during anesthesia.
Second, an increase in PgCO2 (like a reduction in pHi) does not necessarily reflect gut hypoxia. According to the Fick equation, a reduction in blood flow is associated with an increase in the venoarterial gradient in carbon dioxide content and thus in PCO sub 2. However, the decrease in oxygen delivery below a critical value is associated with a much greater increase in the venoarterial PCO sub 2 gradient because the PCO2 generated by the acidotic cells accumulates locally. [9,10] Hence, an increased PgCO2 -PaCO2 gradient should be interpreted as reduced splanchnic perfusion, which does not necessarily indicate splanchnic hypoxia.
The clinical importance of early identification of organ ischemia to prevent the development of multiple organ dysfunction and its associated high mortality rate has been well recognized. [11-13] Monitoring systemic oxygen transport lacks the sensitivity to detect regional, or even global, tissue underperfusion. Gut monitoring has three attractive features. First, splanchnic blood flow is reduced early during even minor cardiovascular alterations in an attempt to preserve blood supply to more vital organs, namely the heart and the brain. Second, the tip of the gut villus may be particularly susceptible to a reduction in blood flow, given the local countercurrent mechanism supplying oxygen. [14] Third, the gut is easily accessible to regional monitoring by inserting a nasogastric or rectal probe.
Our study did not evaluate the clinical utility of PgCO sub 2 monitoring. Several clinical studies have indicated that a low pHi, and especially the persistence of a low pHi, are associated with a greater incidence of organ dysfunction and increased mortality rates in critically ill patients. [11,15-21] Whether gastric tonometry can influence the individual management of an acutely ill patient has not been fully determined. A multicenter study [22] has suggested that pHi-guided therapy may improve outcome, but this was true only in patients with normal pHi on admission, which emphasizes the importance of the early detection of splanchnic hypoperfusion. Another study [23] indicated that gastric tonometry may help to identify failure to wean from mechanical ventilation. Nevertheless, several groups of investigators have stressed that the interpretation of these measurements in individual patients is sometimes difficult. [24-26]
Gas tonometry thus represents an alternative reliable technique for bedside monitoring of gastric perfusion. Clinical studies can now evaluate the clinical utility of gas tonometry. We hope that improved monitoring of tissue perfusion will help to identify those patients who would benefit from increased oxygen delivery, facilitating a more tailored approach to therapy, rather than maintaining supranormal oxygen delivery levels in all "at risk" patients, an approach that has failed to improve survival rates. [27-29]
Back to Top | Article Outline
REFERENCES
1. Fiddian-Green RG, Pittenger G, Whitehouse WM: Back-diffusion of CO2 and its influence on the intramural pH in gastric intestines of rats. J Surg Res 1982; 33:39-48.

2. Grum CM, Fiddian-Green RG, Pittenger GL, Grant BJ, Rothman ED, Dantzker DR: Adequacy of tissue oxygenation in intact dog intestine. J Appl Physiol 1984; 56:1065-9.

3. Guzman JA, Kruse JA: Development and validation of a technique for continuous monitoring of gastric intramucosal pH. Am J Respir Crit Care Med 1996; 153:694-700.

4. Bland JM, Altman DG: Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986; 1:307-10.

5. Knichwitz G, Rotker J, Brusel T, Kuhmann M, Mertes N, Mollhoff T: A new method for continuous intramucosal PCO sub 2 measurement in the gastrointestinal tract. Anesth Analg 1996; 83:6-11.

6. Boda D, Muranyi L: Gastrotonometry: An aid to the control of ventilation during artificial respiration. Lancet 1959; 1:181-2.

7. Salzman AL, Strong KE, Wang H, Wollert PS, VanderMeer TJ, Fink MP: Intraluminal balloonless air tonometry: A new method for determination of gastrointestinal mucosal carbon dioxide tension. Crit Care Med 1994; 1:126-34.

8. Boyd O, Mackay CJ, Lamb G, Bland JM, Grounds RM, Bennett ED: Comparison of clinical information gained from routine blood-gas analysis and from gastric tonometry for intramural pH. Lancet 1993; 341:142-6.

9. Zhang H, Vincent JL: Arteriovenous differences in PCO sub 2 and pH are good indicators of critical hypoperfusion. Am Rev Respir Dis 1993; 148:867-71.

10. Van der Linden P, Rausin I, Deltell A, Bekrar Y, Gilbart E, Bakker J, Vincent JL: Detection of tissue hypoxia by arterio-venous gradient for PCO sub 2 and pH in anesthetized dogs during progressive hemorrhage. Anesth Analg 1995; 80:269-75.

11. Mythen MG, Webb AR: The role of gut mucosal hypoperfusion in the pathogenesis of post-operative organ dysfunction. Intensive Care Med 1994; 20:203-9.

12. Gutierrez G: Cellular energy metabolism during hypoxia. Crit Care Med 1991; 19:619-26.

13. Abraham E: Physiologic stress and cellular ischemia: relationship to immunosupression and susceptibility to sepsis. Crit Care Med 1991; 19:613-8.

14. Fink MP: Gastrointestinal mucosal injury in experimental models of shock, trauma, and sepsis. Crit Care Med 1991; 19:627-41.

15. Gutierrez G, Bismar H, Dantzker DR, Silva N: Comparison of gastric intramucosal pH with measures of oxygen transport and consumption in critically ill patients. Crit Care Med 1992; 20:451-7.

16. Marik PE: Gastric intramucosal pH. A better predictor of multiorgan dysfunction syndrome and death than oxygen-derived variables in patients with sepsis. Chest 1993; 104:225-9.

17. Maynard N, Bihari D, Beale R, Smithies M, Baldock G, Mason R, McColl I: Assessment of splanchnic oxygenation by gastric tonometry in patients with acute circulatory, failure. JAMA 1993; 270:1203-10.

18. Chang MC, Cheatham ML, Nelson LD, Rutherford EJ, Morris JA: Gastric tonometry supplements information provided by systemic indicators of oxygen transport. J Trauma 1994; 37:488-94.

19. Gys T, Hubens A, Neels H: Prognostic value of gastric intramucosal pH in surgical intensive care patients. Crit Care Med 1988; 16:1222-4.

20. Friedman G, Berlot G, Kahn RJ, Vincent JL: Combined measurements of blood lactate concentrations and gastric intramucosal pH in patients with severe sepsis. Crit Care Med 1995; 23:1184-93.

21. Doglio GR, Pusajo JF, Egurrola MA, Bonfigli GC, Parra C, Vetere L, Hernandez MS, Palizas F, Gutierrez G: Gastric mucosal pH as a prognostic index of mortality in critically ill patients. Crit Care Med 1992; 19:1037-40.

22. Gutierrez G, Palizas F, Doglio G, Wainsztein N, Gallesio A, Pacin J, Dubin A, Schiavi E, Jorge M, Pusajo J, Klein F, San Roman E, Dorfman B, Shottlender J, Giniger R: Gastric intramucosal pH as a therapeutic index of tissue oxygenation in critically ill patients. Lancet 1992; 339:195-9.

23. Mohsenifar Z, Hay A, Hay J: Gastric intramural pH as a predictor of success or failure in weaning patients from mechanical ventilation. Ann Intern Med 1993; 119:794-8.

24. Takala J, Parviainen I, Siloaho M, Ruokonen E, Hamalainen E: Saline PCO2 is an important source of error in the assessment of gastric intramucosal pHi. Crit Care Med 1994; 11:1877-9.

25. Riddington JM, Venkatesh B, Clutton-Brock T, Bion J: Potential hazards in estimation of gastric intramucosal pH. Lancet 1992; 340:547.

26. Knichwitz G, Kuhmann M, Brodner G, Mertes N, Goeters G, Brussel T: Gastric tonometry: precision and reliability are improved by a phosphate buffered solution. Crit Care Med 1996; 3:512-6.

27. Hayes MA, Timmins AC, Yau EH, Palazzo M, Hinds CJ, Watson D: Elevation of systemic oxygen delivery in the treatment of critically ill patients. N Engl J Med 1994; 330:1717-22.

28. Hayes MA, Yau EH, Timmins AC, Hinds, Watson D: Response of critically ill patients to treatment aimed at achieving supranormal oxygen delivery and consumption. Chest 1993; 103:886-95.

29. Gattinoni L, Brazzi L, Pelosi P, Latini R, Tognoni G, Pesenti A, Fumagalli R: A trial of goal-oriented hemodynamic therapy in critically ill patients. N Engl J Med 1995; 333:1025-32.

Cited By:

This article has been cited 70 time(s).

Pflugers Archiv-European Journal of Physiology
Submaximal exercise in healthy volunteers: the relationship between gastric mucosal and systemic energy status
Rokyta, R; Matejovic, M; Novak, I; Zeman, V; Krouzecky, A; Novak, J; Trefil, L; Linhartova, K; Sramek, V
Pflugers Archiv-European Journal of Physiology, 443(): 852-857.
10.1007/s00424-001-0761-1
CrossRef
Journal of Cardiothoracic and Vascular Anesthesia
Clinical evaluation of reflectance spectrophotometry for the measurement of gastric microvascular oxygen saturation in patients undergoing cardiopulmonary bypass
Fournell, A; Schwarte, LA; Scheeren, TWL; Kindgen-Milles, D; Feindt, P; Loer, SA
Journal of Cardiothoracic and Vascular Anesthesia, 16(5): 576-581.
10.1053/jcan.2002.126951
CrossRef
Infectious Disease Clinics of North America
Current therapy for sepsis
Dellinger, RP
Infectious Disease Clinics of North America, 13(2): 495-+.

Critical Care Medicine
Gut mucosal-arterial P-CO2 gradient as an indicator of splanchnic perfusion during systemic hypo- and hypercapnia
Guzman, JA; Kruse, JA
Critical Care Medicine, 27(): 2760-2765.

Journal of Investigative Surgery
Gastric mucosal perfusion in dogs: Effects of halogenated anesthetics and of hemorrhage
Evangelista Silva, A; Do Nascimento, P; Lilian Beier, S; Matheus Roberto, W; Gobbo Braz, L; Antonio Vane, L; Marisa Ganem, E; Reinaldo Cerqueira Braz, J
Journal of Investigative Surgery, 21(1): 15-23.
10.1080/08941930701833892
CrossRef
European Surgical Research
Intramucosal pH and pCO(2) do not strictly correlate with intestinal energy metabolism in experimental peritonitis
Ljungdahl, M; Rasmussen, I; Ronquist, G; Haglund, U
European Surgical Research, 32(3): 182-190.

Anasthesiologie Intensivmedizin Notfallmedizin Schmerztherapie
Continuous intramucosal pCO(2)-measuring: Development and status of a new method
Knichwitz, G
Anasthesiologie Intensivmedizin Notfallmedizin Schmerztherapie, 33(2): S78-S84.

European Journal of Vascular and Endovascular Surgery
Intestinal pH(i) studied with continuous saline tonometry during ischaemia and reperfusion in the pig
Frojse, R; Hedberg, B; Backlund, T; Lindahl, O; Haggstrom, M; Angquist, KA; Arnerlov, C
European Journal of Vascular and Endovascular Surgery, 24(2): 150-155.
10.1053/ejvs.2002.1679
CrossRef
Intensive Care Medicine
Effects of fluid challenge on gastric mucosal PCO2 in septic patients
Silva, E; De Backer, D; Creteur, J; Vincent, JL
Intensive Care Medicine, 30(3): 423-429.
10.1007/s00134-003-2115-2
CrossRef
Anesthesia and Analgesia
Comparing methods of clinical measurement: Reporting standards for Bland and Altman analysis
Mantha, S; Roizen, MF; Fleisher, LA; Thisted, R; Foss, J
Anesthesia and Analgesia, 90(3): 593-602.

Intensive Care Medicine
Tissue capnometry: does the answer lie under the tongue?
Maciel, AT; Creteur, J; Vincent, JL
Intensive Care Medicine, 30(): 2157-2165.
10.1007/s00134-004-2416-0
CrossRef
Journal of Applied Physiology
Gut mucosal damage during endotoxic shock is due to mechanisms other than gut ischemia
Lobo, SM; De Backer, D; Sun, QH; Tu, ZZ; Dimopoulos, G; Preiser, JC; Nagy, N; Vray, B; Vercruy, V; Terzi, RGG; Vincent, JL
Journal of Applied Physiology, 95(5): 2047-2054.
10.1152/japplphysiol.00925.2002
CrossRef
Anesthesia and Analgesia
The difference between intramural and arterial partial pressure of carbon dioxide increases significantly during laparoscopic cholecystectomy: The effect of thoracic epidural anesthesia
Nandate, K; Ogata, M; Nishimura, M; Katsuki, T; Kusuda, S; Okamoto, K; Nagata, N; Shigematsu, A
Anesthesia and Analgesia, 97(6): 1818-1823.
10.1213/01.ANE.0000087038.48696.6D
CrossRef
Anesthesia and Analgesia
The early systemic and gastrointestinal oxygenation effects of hemorrhagic shock resuscitation with hypertonic saline and hypertonic saline 6% dextran-70: A comparative study in dogs
Braz, JRC; do Nascimento, P; Filho, OP; Braz, LG; Vane, LA; Vianna, PTG; Rodrigues, GR
Anesthesia and Analgesia, 99(2): 536-546.
10.1213/01.ANE.0000122639.55433.06
CrossRef
Journal of Veterinary Emergency and Critical Care
Optimal endpoints of resuscitation and early goal-directed therapy
Prittie, J
Journal of Veterinary Emergency and Critical Care, 16(4): 329-339.
10.1111/j.1476-4431.2006.00186.x
CrossRef
Acta Anaesthesiologica Scandinavica
Intraperitoneal and sigmoid colon tonometry in porcine hypoperfusion and endotoxin shock models
Koga, I; Stiernstrom, H; Christiansson, L; Wiklund, L
Acta Anaesthesiologica Scandinavica, 43(7): 702-707.

British Journal of Anaesthesia
Gastrointestinal luminal P-CO2 tonometry: an update on physiology, methodology and clinical applications
Kolkman, JJ; Otte, JA; Groeneveld, ABJ
British Journal of Anaesthesia, 84(1): 74-86.

Journal of Cardiothoracic and Vascular Anesthesia
The effect of hypothermia on calculated values using saline and automated air tonometry
Chapman, MV; Woolf, RL; Bennett-Guerrero, E; Mythen, MG
Journal of Cardiothoracic and Vascular Anesthesia, 16(3): 304-307.
10.1053/jcan.2002.124138
CrossRef
Intensive Care Medicine
Monitoring the hepato-splanchnic region in the critically ill patient - Measurement techniques and clinical relevance
Brinkmann, A; Calzia, E; Trager, K; Radermacher, P
Intensive Care Medicine, 24(6): 542-556.

Journal of Applied Physiology
Exercise induces gastric ischemia in healthy volunteers: a tonometry study
Otte, JA; Oostveen, E; Geelkerken, RH; Groeneveld, ABJ; Kolkman, JJ
Journal of Applied Physiology, 91(2): 866-871.

American Journal of Critical Care
Gastric tonometry and enteral nutrition: A possible conflict in critical care nursing practice
Marshall, AP; West, SH
American Journal of Critical Care, 12(4): 349-356.

Pediatric Anesthesia
Intraoperative gastric tonometric examinations in children and infants with a new probe, combined with measurement of the endtidal PCO2
Kiraly, A; Boda, D; Talosi, G; Boda, K
Pediatric Anesthesia, 18(6): 501-507.
10.1111/j.1460-9592.2008.02492.x
CrossRef
Critical Care Medicine
Effects of vasoactive drugs on gastric intramucosal pH
Silva, E; DeBacker, D; Creteur, J; Vincent, JL
Critical Care Medicine, 26(): 1749-1758.

American Journal of Respiratory and Critical Care Medicine
A dobutamine test can disclose hepatosplanchnic hypoperfusion in septic patients
Creteur, J; De Backer, D; Vincent, JL
American Journal of Respiratory and Critical Care Medicine, 160(3): 839-845.

Anesthesia and Analgesia
Regional capnometry with air-automated tonometry detects circulatory failure earlier than conventional hemodynamics after cardiac surgery
Lebuffe, G; Decoene, C; Pol, A; Prat, A; Vallet, B
Anesthesia and Analgesia, 89(5): 1084-1090.

Anesthesia and Analgesia
Early onset of regional intestinal ischemia can be detected with carbon dioxide tension measurement inside the peritoneal cavity
Knichwitz, G; Brussel, T; Reinhold, P; Schaumann, F; Richter, KD; Van Aken, H
Anesthesia and Analgesia, 91(5): 1182-1187.

Intensive Care Medicine
Comparison of air tonometry with gastric tonometry using saline and other equilibrating fluids: an in vivo and in vitro study
Mallick, A; Hartley, G; Bodenham, A; Vucevic, M
Intensive Care Medicine, 24(8): 777-784.

Critical Care
Gastric tonometry versus cardiac index as resuscitation goals in septic shock: a multicenter, randomized, controlled trial
Palizas, F; Dubin, A; Regueira, T; Bruhn, A; Knobel, E; Lazzeri, S; Baredes, N; Hernandez, G
Critical Care, 13(2): -.
ARTN R44
CrossRef
Anasthesiologie Intensivmedizin Notfallmedizin Schmerztherapie
Gastric mucosal tonometry as a monitoring device on a surgical intensive care unit
Pestel, G; Uhlig, T; Gotschl, A; Schmucker, P; Rothhammer, A
Anasthesiologie Intensivmedizin Notfallmedizin Schmerztherapie, 33(2): S94-S98.

Anasthesiologie & Intensivmedizin
Anaemia, blood transfusion and tissue oxygenation
Sielenkamper, A; Bone, HG; Booke, M
Anasthesiologie & Intensivmedizin, 42(5): 304-313.

Physiological Measurement
Validation of a novel method for continuous saline tonometry in a porcine model
Frojse, R; Hedberg, B; Backlund, T; Lindahl, O; Haggstrom, M; Angquist, KA; Arnerlov, C
Physiological Measurement, 22(3): 453-460.

Critical Care
Red blood cell transfusion does not increase oxygen consumption in critically ill septic patients
Fernandes, CJ; Akamine, N; De Marco, FVC; de Souza, JAM; Lagudis, S; Knobel, E
Critical Care, 5(6): 362-367.

Critical Care Clinics
Pharmacologic issues in the management of septic shock
Jindal, N; Hollenberg, SM; Dellinger, RP
Critical Care Clinics, 16(2): 233-+.

Acta Anaesthesiologica Scandinavica
Impact of enteral feeding on gastric tonometry in healthy volunteers and critically ill patients
Rokyta, R; Novak, I; Matejovic, M; Hora, P; Nalos, M; Sramek, V
Acta Anaesthesiologica Scandinavica, 45(5): 564-569.

Critical Care
Esophageal capnometry during hemorrhagic shock and after resuscitation in rats
Totapally, BR; Fakioglu, H; Torbati, D; Wolfsdorf, J
Critical Care, 7(1): 79-84.
10.1186/cc1856
CrossRef
Anesthesiology
Automated detection of gastric luminal partial pressure of carbon dioxide during cardiovascular surgery using the Tonocap
Bennett-Guerrero, E; Panah, MH; Bodian, CA; Methikalam, BJ; Alfarone, JR; DePerio, M; Mythen, MG
Anesthesiology, 92(1): 38-45.

Intensive Care Medicine
Assessment of intestinal tissue oxygenation: the canary sings - but was does the twitter tell us?
Temmesfeld-Wollbruck, B; Mayer, K; Grimminger, F
Intensive Care Medicine, 26(8): 1025-1027.

British Journal of Anaesthesia
Characteristics of time-dependent PCO2 tonometry in the normal human stomach
Kolkman, JJ; Steverink, PJGM; Groeneveld, ABJ; Meuwissen, SGM
British Journal of Anaesthesia, 81(5): 669-675.

Acta Anaesthesiologica Scandinavica
Are we able to interpret the different canary songs?
Tonnesen, TI
Acta Anaesthesiologica Scandinavica, 43(7): 691-694.

British Journal of Anaesthesia
The Haldane effect - an explanation for increasing gastric mucosal Pco(2) gradients?
De Backer, D; Creteur, J; Vincent, JL
British Journal of Anaesthesia, 85(1): 169.

Journal of Cardiothoracic and Vascular Anesthesia
Continuous fiberoptic PCO2 monitoring indicates poorer gastric perfusion during supraceliac aortic clamping than conventional gastric tonometry in humans: A pilot study
Melton, A
Journal of Cardiothoracic and Vascular Anesthesia, 14(6): 666-671.

Anaesthesia and Intensive Care
Serum erythropoietin levels in septic shock
Tamion, F; Le Cam-Duchez, V; Menard, JF; Girault, C; Coquerel, A; Bonmarchand, G
Anaesthesia and Intensive Care, 33(5): 578-584.

New Horizons-the Science and Practice of Acute Medicine
Monitoring of the critically injured patient
Chang, MC
New Horizons-the Science and Practice of Acute Medicine, 7(1): 35-45.

American Journal of Respiratory and Critical Care Medicine
Capnometric recirculation gas tonometry and weaning from mechanical ventilation
Maldonado, A; Bauer, TT; Ferrer, M; Hernandez, C; Arancibia, F; Rodriquez-Roisin, R; Torres, A
American Journal of Respiratory and Critical Care Medicine, 161(1): 171-176.

Journal of Applied Physiology
Effects of hyper- and hypoventilation on gastric and sublingual Pco(2)
Pernat, A; Weil, MH; Tang, WC; Yamaguchi, H; Pernat, AM; Sun, SJ; Bisera, J
Journal of Applied Physiology, 87(3): 933-937.

Critical Care Medicine
Does gastric tonometry monitor splanchnic perfusion?
Creteur, J; De Backer, D; Vincent, JL
Critical Care Medicine, 27(): 2480-2484.

Critical Care Medicine
Intriguing on first sight
Knichwitz, G; Brussel, T
Critical Care Medicine, 27(): 2600.

British Journal of Anaesthesia
In vitro validation of gastric air tonometry using perfluorocarbon FC 43 and 0.9% sodium chloride
Graf, J; Konigs, B; Mottaghy, K; Janssens, U
British Journal of Anaesthesia, 84(4): 497-499.

Journal of Surgical Research
Pneumonia-induced sepsis and gut injury: Effects of a poly-(ADP-ribose) polymerase inhibitor
Lobo, SM; Orrico, SRP; Queiroz, MM; Cunrath, GS; Chibeni, GSA; Contrin, LM; Cury, PM; Burdmann, ED; Machado, AMD; Togni, P; De Backer, D; Preiser, JC; Szabo, C; Vincent, JL
Journal of Surgical Research, 129(2): 292-297.
10.1016/j.jss.2005.06.018
CrossRef
Critical Care Medicine
Intramucosal pCO(2) monitoring using gas tonometry in multiple injured patients
Pestel, G; Uhlig, T; Heinze, H; Rothhammer, A; Schmucker, P
Critical Care Medicine, 27(1): A119.

Chest
Comparisons between sublingual and gastric tonometry during hemorrhagic shock
Povoas, HP; Weil, MH; Tang, WC; Moran, B; Kamohara, T; Bisera, J
Chest, 118(4): 1127-1132.

Journal of Intensive Care Medicine
Endpoints of resuscitation for the victim of trauma
Ward, KR; Ivatury, RR; Barbee, RW
Journal of Intensive Care Medicine, 16(2): 55-75.

Critical Care
Phenylephrine versus norepinephrine for initial hemodynamic support of patients with septic shock: a randomized, controlled trial
Morelli, A; Ertmer, C; Rehberg, S; Lange, M; Orecchioni, A; Laderchi, A; Bachetoni, A; D'Alessandro, M; Van Aken, H; Pietropaoli, P; Westphal, M
Critical Care, 12(6): -.
ARTN R143
CrossRef
Critical Care
Continuous terlipressin versus vasopressin infusion in septic shock (TERLIVAP): a randomized, controlled pilot study
Morelli, A; Ertmer, C; Rehberg, S; Lange, M; Orecchioni, A; Cecchini, V; Bachetoni, A; D'Alessandro, M; Van Aken, H; Pietropaoli, P; Westphal, M
Critical Care, 13(4): -.
ARTN R130
CrossRef
British Journal of Anaesthesia
Gastric mucosal end-tidal PCO2 difference as a continuous indicator of splanchnic perfusion
Uusaro, A; Lahtinen, P; Parviainen, I; Takala, J
British Journal of Anaesthesia, 85(4): 563-569.

British Journal of Anaesthesia
Gastric tonometry: in vivo comparison of saline and air tonometry in patients with cardiogenic shock
Janssens, U; Graf, J; Koch, KC; Hanrath, P
British Journal of Anaesthesia, 81(5): 676-680.

Critical Care Medicine
Gastric intramucosal Pco2 and pH variability in ventilated critically ill patients
Huang, C; Tsai, Y; Lin, M; Tsao, TC; Hsu, K
Critical Care Medicine, 29(1): 88-95.

PDF (89)
Critical Care Medicine
Continuous monitoring of gastric intraluminal carbon dioxide pressure, cardiac output, and end-tidal carbon dioxide pressure in the perioperative period in patients receiving cardiovascular surgery using cardiopulmonary bypass
Imai, T; Sekiguchi, T; Nagai, Y; Morimoto, T; Nosaka, T; Mitaka, C; Makita, K; Sunamori, M
Critical Care Medicine, 30(1): 44-51.

PDF (737)
Critical Care Medicine
The hepatosplanchnic area is not a common source of lactate in patients with severe sepsis
De Backer, D; Creteur, J; Silva, E; Vincent, J
Critical Care Medicine, 29(2): 256-261.

PDF (95)
Critical Care Medicine
Practice parameters for hemodynamic support of sepsis in adult patients in sepsis

Critical Care Medicine, 27(3): 639-660.

Critical Care Medicine
Effects of dopamine, norepinephrine, and epinephrine on the splanchnic circulation in septic shock: Which is best?*
De Backer, D; Creteur, J; Silva, E; Vincent, J
Critical Care Medicine, 31(6): 1659-1667.
10.1097/01.CCM.0000063045.77339.B6
PDF (856) | CrossRef
Critical Care Medicine
Gastric mucosal pH is definitely obsolete-Please tell us more about gastric mucosal PCO2
Vincent, J; Creteur, J
Critical Care Medicine, 26(9): 1479-1481.

Current Opinion in Critical Care
Gastric and sublingual capnometry
Creteur, J
Current Opinion in Critical Care, 12(3): 272-277.
10.1097/01.ccx.0000224874.16700.b6
PDF (132) | CrossRef
European Journal of Anaesthesiology (EJA)
Gastric mucosal-to-end-tidal PCO2 difference during major abdominal surgery: influence of the arterial-to-end-tidal PCO2 difference?
Lebuffe, G; Onimus, T; Vallet, B
European Journal of Anaesthesiology (EJA), 20(2): 147-152.

PDF (842)
European Journal of Anaesthesiology (EJA)
Effects of intra‐aortic balloon counterpulsation on parameters of tissue oxygenation
Heinze, H; Heringlake, M; Schmucker, P; Uhlig, T
European Journal of Anaesthesiology (EJA), 23(7): 555&hyhen;562.
10.1017/S0265021505001973
PDF (123) | CrossRef
European Journal of Anaesthesiology (EJA)
A new simple tool for tonometric determination of the PCO2 in the gastrointestinal tract: in vitroandin vivovalidation studies
Boda, D; Kaszaki, J; Tálosi, G
European Journal of Anaesthesiology (EJA), 23(8): 680&hyhen;685.
10.1017/S026502150600055X
PDF (90) | CrossRef
European Journal of Anaesthesiology (EJA)
Pilot study with air-automated sigmoid capnometry in abdominal aortic aneurysm surgery
Warembourg, H; Vallet, B; Lebuffe, G; Decoene, C; Raingeval, X; Lokey, J; Pol, A
European Journal of Anaesthesiology (EJA), 18(9): 585-592.

PDF (236)
Shock
INTESTINAL BLOOD FLOW AND INTRAMUCOSAL pH IN EXPERIMENTAL PERITONITIS
Ljungdahl, M; Rasmussen, I; Haglund, U
Shock, 11(1): 44-50.

PDF (580)
Shock
Short-Term Effects of Phenylephrine on Systemic and Regional Hemodynamics in Patients With Septic Shock: A Crossover Pilot Study
Morelli, A; Lange, M; Ertmer, C; Dünser, M; Rehberg, S; Pietropaoli, P; Traber, DL; Westphal, M; Bachetoni, A; D'Alessandro, M; Van Aken, H; Guarracino, F
Shock, 29(4): 446-451.
10.1097/SHK.0b013e31815810ff
PDF (164) | CrossRef
Shock
Decreases in Mesenteric Blood Flow Associated With Increases in Sublingual Pco2 During Hemorrhagic Shock
Povoas, HP; Weil, MH; Tang, W; Sun, S; Kamohara, T; Bisera, J
Shock, 15(5): 398-402.

PDF (3708)
Back to Top | Article Outline
Keywords:
Gastric intramucosal carbon dioxide pressure. Monitoring, splanchnic: gastric tonometry; gas tonometry; saline tonometry. Oxygen delivery. Splanchnic ischemia.

© 1997 American Society of Anesthesiologists, Inc.

Publication of an advertisement in Anesthesiology Online does not constitute endorsement by the American Society of Anesthesiologists, Inc. or Lippincott Williams & Wilkins, Inc. of the product or service being advertised.
Login

Article Tools

Images

Share