Critical care medicine
-
Critical care medicine · Jan 1994
Comparative StudyOxygen Fick and modified carbon dioxide Fick cardiac outputs.
To compare cardiac outputs estimated from the classical oxygen Fick and modified CO2 Fick methods with thermodilution cardiac output. The modified CO2 Fick cardiac output was obtained by replacing the oxygen uptake (VO2) in the Fick equation with the CO2 production (VCO2) divided by either an assumed or measured value of the respiratory exchange ratio or with an independently determined constant (Crit Care Med 1991; 19:1270-1277). ⋯ We conclude from this study that thermodilution cardiac output is more closely related to cardiac output calculated from modified CO2 Fick methods than to oxygen Fick cardiac output. Since cardiac output calculated with the modified CO2 Fick method 3 obviates the difficulties associated with measuring VO2 accurately and requires neither an assumption of nor measurement of the respiratory exchange ratio, method 3 may prove to be clinically useful for continuous cardiac output monitoring via oximetry in ICU patients.
-
Critical care medicine · Jan 1994
Subglottic positive end-expiratory pressure in extubated patients recovering from acute lung injury.
To examine the glottic function in extubated patients recovering from acute lung injury by simultaneous measurement of airway opening and subglottic airway pressures while patients are breathing at ambient pressure and receiving continuous positive airway pressure by a face mask. ⋯ Our data imply that patients recovering from acute lung injury create an intratracheal positive end-expiratory pressure by braking the expiratory airflow, probably by glottic narrowing. Despite compensatory glottic narrowing, extubated patients with reduced lung function may benefit from higher levels of continuous positive airway pressure.
-
Critical care medicine · Jan 1994
Comparative StudyIncreased venous-arterial carbon dioxide tension difference during severe sepsis in rats.
To test the hypothesis that decreases in blood flow during septic shock lead to increases in the venous-arterial PCO2 difference in a rat model of sepsis. ⋯ We conclude that the increase in the venous-arterial PCO2 gradient in severe sepsis appears to be related to reductions in cardiac output.
-
Critical care medicine · Jan 1994
Early hydrogen peroxide-induced pulmonary endothelial cell dysfunction: detection and prevention.
To determine a) whether hydrogen peroxide-induced, early lung endothelial cell dysfunction can be detected in an isolated, perfused, rat lung model; and b) whether the organic phosphothioate N-(2-mercaptoethyl)-1,3-propanediamine, which protects cells in culture against hydrogen peroxide-mediated damage, can exert the same protection in this model. ⋯ a) Hydrogen peroxide-induced lung endothelial cell dysfunction was detected at an early stage, before any permeability defect appeared; b) N-(2-mercaptoethyl)-1,3-propanediamine protected against such damage.