Non invasive versus invasive blood gas monitoring in critically ill patients on mechanical ventilator (Evaluation of reliability, accuracy, and economic impact

Abstract

In group (II) {haemodynamic instability) all patients were hypocarpic and hypoxemic due to haemodynamic unstabiliry states and poor or critical perfusion rate.

In group (III) there is no pulmonary exchange problems in this patients gorup.

This study proved that there was significant difference between Sa02 and Sp02 in hypoxemic patients and insignificant difference in non hypoxemic patients in group (!), and there was significant difference

The object of this study is compare pulse oxymetry oxygen saturation (Sp02 ) and end-tidal carbon dioxide (PetC02) measured by capnometry with arterial blood gas analysis in mechanically ventilated ICU patients under different clinical situations and assess the ability of both pulse oxymetry and capnometry to identify potential respiratory problems during mechanical ventilation and after withdrawal of ventilator.

Our study was done in 180 patients admitted to ICU of South Cancer Institute, Assiut University and International Cancer Institute, Cairo University, during the period from April 1999 to April 2002. Those patients were classified according to pulmonary functions and haemodynamic status into three equal groups (60 patients per.group).

In group (I) two-thirds of patients were hypoxemic (Sa02<90%) and hypercarpic (PaC02>45 mmHg), and one-third of them were non hypoxemic (Sa02 >90%) and normocabnic (PaC02 ::;45 mmHg).. All patients were connected to mechanical ventilation.