Clinical Significance Of The Monitoring Of Gastric Intramucosal PH-value With Severe Pneumonia Of Pediatric Patients

Research BackgroundSevere pneumonia is a common disease among infants. The younger the infant means the less maturity of his/her respiratory organ and the less immunity to the disease, which raised the possibility for pulmonary infection and immune reaction of local organs. Upon infection, the pathogenic bacteria and the endotoxin it generated will cause the organs to generate inflammatory mediators, which finally leading to organ function failure through a process of cascade effect in which ischemia and hypoxia, injury and death of cells are resulted. The severely infected pediatric patients will suffer a diminishing blood flow in internal organs due to various reasons which induced a redistribution of blood flow. The gastrointestinal organs are the first organs suffered from such a diminishing of blood flow and are inclined to face hypoxic-ischemic, and more importantly, they are also the last organs to recover in the whole recovery process of blood circulation, together make them the best indicators for blood flow conditions throughout the body. Once the gastrointestinal mucosa suffered acute organ damages, the weakening immune barrier and the translocation of intestinal bacteria will cause endotoxemia and sepsis or even cause Systemic Inflammatory Response Syndrome (SIRS) again, which may finally lead to Multiple Organ Dysfunction Syndrome (MODS).The most commonly used clinical method for gastrointestinal hypoxic-ischemic detecting in pediatric patients with severe pneumonia in early stages is themeasurement of Gastric Intramucosal pH (pHi). This method can exclude the influences exerted by acid base balance, while gastric-arterial PCO2 gap is considered to be an accurate indicator for intramucosal or splanchnic perfusion conditions. Traditionally, researchers also believe that Blood Lactate can serve as an effective indicator for tissue perfusion. Upon these considerations, this paper carried out a comparison between Blood lactate and gastric intramucosal pH, so as to identify which one better reflect the tissue perfusion and oxygenation conditions.Contemporarily there's still no relative literature or research report about the clinical significance of the monitoring of gastric pH-value of pediatric patients with severe pneumonia, thus provided the necessity for this research.Research ObjectiveIn this research, we utilize air tonometry catheter to measure the indicators of intramucosal perfusion conditions, such as PgCO₂, Pg-aCO₂ and standard pHi. We will also make comparison about the correlations between pHi and arterial blood lactate, P50, PO_2(x), PaO₂/FiO₂, gastric-arterial PCO₂ gap so as to provide insights about which indicator is most sensitive as far as the reflection of tissue perfusion and oxygenation conditions to be concerned, and if there exist significant differences in Lac, P50,Po_2(x), PaO₂/FiO₂,Pg-aCO₂, pHi before and after the surgical treatment.Material and Methods1. Research Objects: From November, 2006 to March, 2007, 30 pediatric patients with severe pneumonia which received mechanical ventilation treatment in Pediatric Intensive Care Unit(PICU) of Children's Hospital Affiliated to Zhejiang University School of Medicine were chosen at random. Among the research objects there are 18 males and 12 females, age from 44 days to 21 months with an average age of 6.58±5.22 months, weigh 3.8 to 9.5kg with an average weight of 5.83 ± 2.56kg. Among them there are 8 patients with congenital heart disease (CHD), and 30 patients with respiratory failure.2. Research Methods:1) Mechanical Ventilation Treatment Methods: Evita-4 ventilator machine made by Drager Corp.(Germany), utilize PSV-SIMV mode.2 ) Sedation Methods: 3-8μg/kg.h Fentany Injection and 1-5 μg/kg.h Midazdam Injection, slow continuously transfusion by vein.3 ) Fasting and implementation of air tonometric catheters upon hospitaladmissions for pediatric patients, dynamic monitoring of PgCO₂ through a Datex-OhmedaS/5^TMmonitor.4 ) Experimental Indicators: PgCO₂ were measured 15 minutes before mechanical ventilation treatment (T₁) for all of 30 patients, measured again for 1h, 3h, 8h, 13h, 18h, 24h after mechanical ventilation treatment, labeled T₁, T₂, T₃, T₄, T₅, T₆, T7, respectively. Together with each value of T, arterial blood gas was determined at all of the above time points. The Pg-aCO₂ and standard pHi are calculated on the basis of formula, P50, lac, PaO₂/FiO₂ and PO_2(x) in the analysis will also be recorded.The data in the experiment will be expressed in the form of Mean ± Standard deviation ( X|- ± SD).Pearson Correlate analysis will be employed to analyze correlation between pHi and Pg-aCO₂, P50, Lac, PaO₂/FiO₂, PO_2(x). The change in indicators before and after mechanical ventilation treatment will be testified by t-test, in which significant difference are indicated if P<0.05. All the statistical analysis will be realized with SPSS 10.0.Research Results1. The change in Pg-aCO₂ and standard Phi, P50, Lac, PaO₂/FiO₂, PO_2(x) 24 hours before and after the mechanical ventilation treatment for the pediatric patients are as follows:1) Pg-aCO₂ was lowered gradually upon the treatment. There's significant difference between T₁ and T₅, T₆, T₇; T₂ and T₆, T₇; T₃ and T₇ (P<0.05). There's no significant difference between each pair of the other time points.2) pHi was leveled up gradually upon the treatment. There's significant difference between each pair of the time points, except for T₄ and T₅; T₅ and T₆; T₆ and T₇ (P<0.05).3) P50 was lowered gradually upon the treatment. There's significant difference between T₁ and T₆, T₇ (P<0.05). There's no significant difference between each pair of the other time points.4) Lac was lowered gradually upon the treatment. There's significant difference between each pair of the time points, except for T₁ and T₂; T₃ and T₄; T₄ and T₅, T₆, T₇; T₅ and T₆, T₇; T₆ and T₇ (P<0.05).5) PO_2(x) was leveled up gradually upon the treatment. There's significant difference between each pair of the time points, except for T₁ and T₂; T₂ and T₃; T₃ and T₄; T₄ and T₅, T₆; T₅ and T₆, T₇; T₆ and T₇ (P<0.05).6) PaO₂/FiO₂ was leveled up gradually upon the treatment. There's significantdifference between T₁ and T₆; T₁ and T₇ (P<0.05), There's no significant difference between other each pair of the time points.2. Correlation between Phi and Pg-aCO₂, P50, Lac, PO_2(x), PaO₂/FiO₂ during the 24 hours are as follows:1) There's negative correlation between pHi and Pg-aCO₂ (P<0.001).2) There's negative correlation between pHi and P50 (P<0.001).3) There's negative correlation between pHi and Lac (P<0.001).4) There's positive correlation between pHi and PO_2(x) (P<0.01).5) There's positive correlation between pHi and PaO₂/FiO₂ (P<0.05).Conclusion1. Hypoxic-ischemic existed among pediatric patients with severe pneumonia.2. Gastric Intramucosal pH(pHi) can serve as a better sensitive and accurateindicator for tissue perfusion and oxygenation conditions.