The American review of respiratory disease
-
Am. Rev. Respir. Dis. · Sep 1993
Comparative StudyTidal volume measurements in newborns using respiratory inductive plethysmography.
Respiratory inductive plethysmography (RIP) is a well-accepted noninvasive technology for monitoring breathing patterns in adults. Prior attempts to calibrate this device in babies have been fraught with technical difficulties, thereby limiting applications in this population. Recently, a new method, qualitative diagnostic calibration (QDC), has been shown to provide accurate calibration of tidal volume in adults. ⋯ In the supine and prone postures, weighted mean difference between RIP (VT) and PNT (VT) and 95% confidence intervals were -0.05 ml (-0.27, 0.18) and -0.32 ml (-0.08, 0.55), respectively. There was no difference in the accuracy of RIP relative to PNT calibrated during active sleep when thoracoabdominal incoordination was present or quiet sleep when it was not in either the supine or the prone postures. Therefore, in full-term infants, RIP calibrated with QDC solely in the supine posture provides clinically acceptable measurements of VT in both supine and prone postures.
-
Am. Rev. Respir. Dis. · Sep 1993
Comparative StudyComparison of ventilatory support with intratracheal perfluorocarbon administration and conventional mechanical ventilation in animals with acute respiratory failure.
We investigated the efficacy of intratracheal perfluorocarbon (PFC) administration combined with mechanical ventilation to support gas exchange in adult animals with acute respiratory failure. These were compared with a similar group of animals treated with continuous positive-pressure ventilation (CPPV) with respect to respiratory parameters and postmortem lung histology. After lung lavage with saline, 18 adult rabbits were divided into three groups (n = 6 per group). ⋯ Only in the PFC group were significant decreases in airway pressures and increase in respiratory system compliance seen. In the CPPV group, PaO2 stayed around 60 mm Hg and PaCO2 gradually increased. PFC treatment with conventional mechanical ventilation in acute respiratory failure proved to be a successful supportive technique to improve gas exchange at low inflation pressures.
-
Am. Rev. Respir. Dis. · Aug 1993
Use of capnography for assessment of the adequacy of alveolar ventilation during weaning from mechanical ventilation.
A prospective study was conducted to determine the reliability of noninvasive end-tidal CO2 (PETCO2) monitoring as a reflection of arterial CO2 tension (PaCO2) during weaning from mechanical ventilation (MV). Simultaneous PaCO2 and PETCO2 determinations were compared during MV and again during a spontaneous breathing trial just before returning the patient to MV. Three groups of patients recovering from acute respiratory failure were evaluated. ⋯ However, PETCO2 is less sensitive to changes in PaCO2 for patients with parenchymal lung disease, particularly patients with emphysema. Interpretation of capnographic data requires a full understanding of its limitations. An approach to capnographic monitoring during weaning is discussed.
-
Am. Rev. Respir. Dis. · Aug 1993
Tracheal gas insufflation augments CO2 clearance during mechanical ventilation.
A technique that improves the efficiency of alveolar ventilation should decrease the pressure required and reduce the potential for lung injury during mechanical ventilation. Alveolar ventilation may be improved by replacing a portion of the anatomic dead space with fresh gas via an intratracheal catheter. We studied the effect of intratracheal gas insufflation as an adjunct to volume cycled ventilation in eight sedated, paralyzed patients with a variety of lung disorders. ⋯ The highest catheter flow (6 L/min) and most distal catheter position (1 cm above the carina) were the most effective combination tested, averaging a 15% reduction in PaCO2 (range 9 to 23%). Certain characteristics of the expiratory capnogram were helpful in predicting the observed reduction in PaCO2. Tracheal gas insufflation may eventually prove a useful adjunct to a pressure-targeted strategy of ventilatory management (in either volume-cycled or pressure controlled modes), particularly when the total dead space is heavily influenced by its anatomic component.