Chest
-
Comparative Study
Comparison of central-venous to mixed-venous oxygen saturation during changes in oxygen supply/demand.
Because central venous O2 saturation (superior vena cava, ScvO2) can be monitored with less patient risk than mixed venous O2 saturation (pulmonary artery, SvO2), we examined the correlations between SvO2 and ScvO2 over a broad range of cardiorespiratory conditions, including hypoxia, hemorrhage, and resuscitation in anesthetized dogs. The correlation coefficient (r) between SvO2 and ScvO2 in 179 simultaneously drawn blood samples from 22 dogs was 0.97. ⋯ In each dog the changes in ScvO2 closely paralleled the changes in SvO2. Although absolute values of ScvO2 are not sufficiently identical to SvO2 to calculate O2 uptake or pulmonary shunt precisely, close tracking of changes in the two sites across a wide range of hemodynamic conditions warrant further consideration of ScvO2 for patient monitoring of trends in O2 supply/demand.
-
Hemodynamic and pulmonary gas exchange consequences of 20 percent intravenous fat emulsion infusion (3.0 +/- .3 mg/kg/min) were evaluated in 19 patients who demonstrated ARDS. Lipid infusion precipitated a significant reduction in PaO2/FIO2 from 241 +/- 50 to 184 +/- 41 (mean +/- SD) and increased MPAP from 26.0 +/- 5.1 to 31.8 +/- 4.8 mm Hg, pulmonary vascular resistance from 149 +/- 78 to 179 +/- 61 dyne.s/cm5 and pulmonary venous admixture (Qva/Qt) from 20.7 +/- 15.2 to 30.6 +/- 8.6 percent. ⋯ We conclude that intravenous lipid administration was associated with increased MPAP and Qva/Qt in patients with ARDS, particularly when accompanied by septicemia. Although these alterations resolved after the lipid infusion was terminated, we suggest that prudent measures should be taken to guarantee adequate oxygenation during intravenous fat emulsion therapy in patients suffering from ARDS.
-
Pulmonary artery perforation by flow-directed catheters is associated with high mortality, particularly in heparinized patients. We report a recent case and discuss recognition and management.
-
Elimination half-life and apparent volume of distribution of theophylline were determined in ten healthy volunteers who used smokeless tobacco (snuff or chewing tobacco) regularly but did not smoke cigarettes. Serum concentrations of the acute phase reactant alpha 1-acid glycoprotein (AAG) were also measured. ⋯ All these values are comparable to values reported for nonsmokers. These results suggest that nonsmoking users of ST should be considered to be tobacco nonusers for purposes of planning theophylline dosing and monitoring strategies.