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M Chulay

Publications and source records attributed to M Chulay.

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Clinical comparison of two- and three-wavelength systems for continuous measurement of venous oxygen saturation.

OBJECTIVE: To evaluate clinically the accuracy of continuous SvO2 systems to reflect reference SvO2 values over a 24-hour period. DESIGN: Randomized clinical trial. SETTING: Six-bed cardiac surgical intensive care unit of a 540-bed federal facility. POPULATION: Sixty postoperative cardiac patients. INTERVENTIONS: Random assignment to a two- or three-wavelength continuous SvO2 catheter for postoperative SvO2 monitoring. At 4-hour intervals over a 24-hour period, mixed venous blood samples were analyzed with a reference cooximeter and compared with the monitor value of the SvO2 catheter. MAIN OUTCOME MEASURES: A reference cooximeter method to measure SvO2 in mixed venous blood; SvO2 as measured by the in-line, SvO2 catheter system. RESULTS: SvO2 measured by the three-wavelength system did not differ significantly from the reference SvO2 measurement. In contrast, SvO2 measured by the two-wavelength system was significantly lower than the reference SvO2 measurement within 4 hours of admission to the critical care unit and remained significantly lower throughout the 24-hour study period. CONCLUSIONS: The results of this clinical study confirmed a previous study in dogs, showing that SvO2 is measured more accurately by the three-wavelength continuous monitoring system.

Adult

Pulmonary artery pressure measurement in patients with elevated pressures: effect of backrest elevation and method of measurement.

OBJECTIVE: To determine whether pulmonary artery pressure measurement is accurate if the head of the bed is elevated; to compare the end-expiratory graphic recording and digital monitor methods for pulmonary artery pressure measurement; to determine whether either mean arterial pressure or mixed venous oxygen saturation changes during backrest elevation. DESIGN: Nonrandomized clinical trial. SETTING: A six-bed cardiac surgical intensive care unit of a 540-bed federal facility. POPULATION: Twenty-five postoperative cardiac surgical patients with elevated pulmonary artery pressures (systolic higher than 35 mm Hg). INTERVENTIONS: In supine patients pulmonary artery pressures were measured at each of the following backrest elevations: 0, 20, 30, 45 and again at 0 degrees. Measurements were obtained once during mechanical ventilation and once during normal breathing after extubation. MAIN OUTCOME MEASURES: End-expiratory graphic recording of pulmonary artery pressures; digital monitor values of pulmonary artery pressures; mean arterial pressure; and mixed venous oxygen saturation. RESULTS: No statistical difference was found in pulmonary artery pressures measured at each of the backrest elevations during mechanical ventilation or normal breathing after extubation. Pulmonary artery diastolic and pulmonary capillary wedge pressures obtained with the digital monitor method were significantly lower than the end expiratory graphic recording method during normal breathing after extubation but not during mechanical ventilation. No changes in mean arterial pressure or mixed venous oxygen saturation occurred during backrest elevation. CONCLUSIONS: These results show that pulmonary artery pressures can be measured accurately with the head of the bed in an elevated position. The data indicate that obtaining pulmonary artery pressure measurements from the digital display of the bedside monitor is accurate when respiratory wave form fluctuations are minimal but may lead to inaccurate values with prominent respiratory fluctuations. Further research is needed to validate this finding in different patient populations and with other models of monitoring equipment.

Adult

Arterial blood gas changes with a hyperinflation and hyperoxygenation suctioning intervention in critically ill patients.

Limited data are available on the efficacy of a common endotracheal suctioning intervention to prevent postsuctioning decreases in arterial oxygenation (PaO2). This study evaluated the effect on Pao2 of five hyperinflation (tidal volume 1.5 times normal) and hyperoxygenation breaths, administered before and after each of two consecutive endotracheal suctioning passes, with use of a manual resuscitation bag (PMR-2 model). The convenience sample consisted of 32 patients with endotracheal tubes who were observed within 24 hours of coronary artery bypass surgery. After the implementation of this standard suctioning intervention, there was a significant increase in PaO2 from baseline values. Only one subject had a decrease in PaO2 (44 mm Hg) after the intervention. In addition, a clinical measure of alveolar-capillary gas exchange (PaO2/PAO2 ratio) was found to be a significant predictor of PaO2 after suctioning, accounting for 38% of the variance. The data from this study support the efficacy of administering five hyperinflation and hyperoxygenation breaths, with use of a manual resuscitation bag, before and after endotracheal suctioning in stable patients after coronary artery bypass surgery. Further study is necessary to determine the efficacy of this suctioning intervention in patients with other respiratory problems.

Adult

Efficacy of a hyperinflation and hyperoxygenation suctioning intervention.

Limited data are available on the efficacy of a common endotracheal suctioning intervention to prevent decreases in arterial oxygenation (PaO2) after endotracheal suctioning. We evaluated the effect of five hyperinflation breaths with hyperoxygenation, administered before and after endotracheal tube suctioning, in anesthetized, paralyzed sheep with normal lung function and with abnormal lung function induced by pulmonary acid aspiration. Using a second ventilator to deliver hyperinflation and hyperoxygenation prevented PaO2 from falling below control values after endotracheal tube suctioning in animals with either normal or abnormal lung function. The PaO2 rise after hyperinflation and hyperoxygenation in animals with abnormal lung function, however, was less than that observed in animals with normal lung function. Using manual resuscitation bags to deliver the hyperinflation breaths with hyperoxygenation prevented PaO2 from falling below control values after endotracheal suctioning in animals with normal lung function. When lung function was abnormal, however, there were significant PaO2 decreases when manual resuscitation bags were used to deliver the intervention. These results highlight the difference in PaO2 response when hyperinflation and hyperoxygenation suctioning interventions are delivered with mechanical versus manual techniques. These results also emphasize that the response to hyperinflation and hyperoxygenation differs in subjects with normal versus abnormal lung function. Laboratory evaluation of endotracheal tube suctioning interventions should use abnormal lung function models, rather than normal lung function models, to approximate more closely the critically ill patient population that requires suctioning.

Animals

Esmolol HCl.

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Adrenergic beta-Antagonists