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Published on: May 21, 2019
Comparison of gastric intramucosal pH and standard perfusional measurements in pediatric septic shock
B Krafte-Jacobs1, J Carver, J D Wilkinson
1Department of Critical Care, Children's National Medical Center, Washington, DC, USA.
Insights
Gastric tonometry may help differentiate survivors from non-survivors in pediatric septic shock. However, intramucosal pH (pHi) values are not reliable predictors of adverse clinical events in these critically ill children.
Area of Science:
- Pediatric Critical Care Medicine
- Gastroenterology
- Shock Pathophysiology
Background:
- Septic shock in children presents significant morbidity and mortality.
- Early indicators of clinical deterioration are crucial for timely intervention.
- Gastric tonometry offers a potential method to assess splanchnic perfusion.
Purpose of the Study:
- To evaluate the effectiveness of gastric tonometry in predicting outcomes in pediatric septic shock.
- To determine if intramucosal pH (pHi) can serve as an early warning for adverse events.
Main Methods:
- A prospective study involving 8 critically ill pediatric septic shock patients.
- Simultaneous measurement of standard hemodynamic and oxygen transport data.
- Calculation of intramucosal pH (pHi) from gastric intramucosal PCO2 (PiCO2) using tonometry.
Main Results:
- Mean pHi was significantly lower in non-survivors (7.32) compared to survivors (7.48).
- pHi correlated with urine output, but not consistently with other perfusion markers like lactate.
- Low pHi (<7.35) showed limited accuracy in predicting adverse clinical events (67% sensitivity, 74% specificity).
Conclusions:
- Gastric tonometry may assist in distinguishing survivors from non-survivors in pediatric septic shock.
- Splanchnic perfusion assessment via tonometry shows poor correlation with standard clinical and hemodynamic parameters.
- Low pHi values are not consistently predictive of concurrent or subsequent adverse clinical events.
Objective:
To examine the utility of gastric tonometry as an early indicator of morbidity and mortality in pediatric patients with septic shock.
Design:
Prospective clinical study.
Setting:
Multidisciplinary pediatric ICU.
Patients:
Eight critically ill pediatric patients with septic shock and with pulmonary artery and gastric tonometry catheters in place.
Interventions:
Standard perfusional data including cardiac index, oxygen content (arterial, mixed venous), oxygen delivery, oxygen consumption, urine output, capillary refill, and lactate value were measured every 4 h. Intramucosal pH (pHi) was calculated from simultaneous tonometric measurements of gastric intramucosal PCO2 (PiCO2). Mean pHi values were compared between survivors and nonsurvivors. Tonometric data were compared with standard perfusional data by regression analysis. Low pHi values (< 7.35) were temporally compared with occurrence screens for adverse clinical events, (cardiopulmonary arrest, acute hemorrhage, and significant hypotension or dysrhythmias).
Measurements And Main Results:
Sets (n = 108) of paired data were collected from 8 patients (age 7 to 168 months) representing 4 deaths. The mean pHi in nonsurvivors (7.32 +/- 0.18) was significantly lower than that in survivors (7.48 +/- 0.07). Both pHi and PiCO2 were correlated with urine output by regression analysis. The pHi, but not PiCO2 correlated with extraction ratio and lactate level. There were no other significant correlations noted. Analysis of the ability of pHi values to predict adverse clinical events revealed that pHi less than 7.35 accurately predicted 26 of 39 concurrent or subsequent adverse clinical events. However, 24 of 50 pHi values less than 7.35 showed no association with similar adverse events, either concurrent or subsequent. The pHi had a sensitivity of 67%, a specificity of 74%, a positive predictive value of 52%, and an efficiency of 72% in predicting these adverse events.
Conclusion:
Use of gastric tonometry in pediatric septic shock patients appears to distinguish survivors from nonsurvivors. However, in general, tonometric assessment of splanchnic perfusion correlates poorly with standard clinical, hemodynamic, oxygen transport, or metabolic measurements of perfusion. Low pHi measurements are not predictive of concurrent or subsequent adverse clinical events.

