الفهرس 
Acid – Base HomeostasisOnly 14 pages are availabe for public view
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Abstract
Monitoring of gas exchange (oxygenation and ventilation) is one of the important issues in PICU, PO2 and PCO2 are two of the most important respiratory parameters in the treatment of critically ill child, as the Extremes of these two factors account for many complications and directs the plans for management and have effects on prognosis after that, which will have their impacts on the future of these children. Arterial blood gases analysis is the gold standard for PaO2 and PaCO2 measurements, but, this method have many disadvantages, such as, each measurement needs withdrawal of arterial blood sample and laboratory, relatively expensive, time delay in obtaining laboratory results, intermittent method, in addition, infection, hemorrhage and vessel occlusion can occur with this invasive method. Pulse oximetry which is widely used in clinical setting has certain limitations, mainly related to the physicochemical properties of hemoglobin the oxyhemoglobin dissociation curve clearly shows that a DROP of SpO2 from 100 to 90%, i.e., by only 10% corresponds with a decrease in PaO2 by as much as 40 mmHg. Moreover, Pulse oximetry reflects alterations associated with O2 but not with CO2. This merits search for alternative methods which would be more reliable than pulse oximetry and less invasive than repeated. blood sampling. Transcutaneous partial pressure of oxygen (PtcO2) and carbon dioxide (PtcCO2) monitoring, introduced into 1970s, is based on the principle that dissolved gases diffuse through tissues, due to this property gas pressure may