The analyses utilized in these studies are highly variable and fail to consider physiologic dead space/severity of pulmonary disease and/or their effect on the relationship between PaCO 2 and PetCO 2. Critics of capnometer usage cite multiple studies which demonstrate that PetCO 2 and PaCO 2 do not reliably correlate in some clinical situations 12, 16, 17. There are many studies evaluating the accuracy of mainstream, sidestream and microstream capnometer technologies in the literature 11, 12, 13, 14, 15. A new technology for sidestream systems (Microstream, Oridion Medical, Inc., Danville, CA) is now available that uses very low flow rates (50 mL/min) to preserve the accuracy and resolution of the waveform as well as eliminating secretion/moisture-related occlusion problems by the use of special filters 7. Sidestream methods utilize an infrared PCO 2 sensor in a monitor that may be located far from the patients 10. On the other hand, sidestream capnometers aspirate samples from the airway through tubing attached to a sampling line and airway adapter between the ETT and the ventilation circuit. Mainstream capnometers are devices in which the infrared source and PCO 2 detector are placed between the proximal endotracheal tube (ETT) and the ventilator circuit 7, 9. The technique is named based on the localization of the PetCO 2 sensor 7, 8. It is possible to measure PetCO 2 by mainstream or sidestream capnometer technologies. The patient protection enhancements provided by end-tidal PCO 2 (PetCO 2) monitoring also include the detection of invasive airway disconnection, dislodgement or obstruction, prediction of underlying airway or lung pathologies and monitoring the effectiveness of cardiopulmonary resuscitation 3, 5, 6. Detection of exhaled PCO 2 (end-tidal PCO 2) has proven to be a valuable mechanism to confirm tracheal intubation and to recognize accidental esophageal intubations, among other critical patient safety benefits 4. But ABG is an invasive method and does not provide continuous monitoring 2.Ĭapnometers, which continuously monitor PCO 2 levels and display the waveform of PCO 2 in exhaled air non-invasively, provide information on the adequacy of ventilation 3. The current gold standard method for the measurement of partial pressure of carbon dioxide in the blood (PaCO 2) is the arterial blood gas (ABG) method. The monitoring of carbon dioxide (CO 2) level is essential for diagnosis and therapeutic guidance in mechanically ventilated patients 1. Both capnometer methods may be useful in predicting the trend of PaCO 2 due to significant correlations with the gold standard measurement in cases with severe pulmonary disease or increased physiological dead space –despite reduced accuracy. It was found that the novel microstream capnometer method for PetCO 2 measurements provided no superiority to the traditional mainstream method. In cases with increased physiologic dead space ventilation, the agreement levels of mainPetCO 2 and microPetCO 2 methods became distorted (bias ± precision values of 20.9 ± 11.2 and 25.0 ± 11.8 mm Hg, respectively) even though mainPetCO 2 and microPetCO 2 were highly correlated (r = 0.78 and r = 0.78, respectively). In those with severe pulmonary disease, the mainPetCO 2 and microPetCO 2 methods were highly correlated with PaCO 2 (r = 0.80 and r = 0.81, respectively) however, the biases of both methods increased (14.8 ± 9.1 mmHg and 16.2 ± 9.0 mmHg, respectively). Although both mainstream PetCO 2 (mainPetCO 2) and microstream PetCO 2 (microPetCO 2) were moderately correlated (r = 0.63 and r = 0.68, respectively) with PaCO 2 values, mainPetCO 2 was in better agreement with PaCO 2 in all subjects (bias ± precision values of 3.8 ± 8.9 and 7.3 ± 8.2 mmHg, respectively). Data were collected prospectively from mainstream and microstream capnometer simultaneously and compared with PaCO 2 results. The study was carried out on 174 subjects with a total of 1338 values for each method. This was a prospective single-center comparative study. We hypothesized that the novel microstream method would superior compared to the traditional mainstream method in predicting PaCO 2. The objective of this study was to evaluate a novel microstream method by comparison with PaCO 2 and the more standard mainstream capnometer in intubated pediatric patients.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |