Journal of critical care
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Journal of critical care · Jun 1997
Randomized Controlled Trial Comparative Study Clinical TrialPositive pressure inspiration differentially affects right and left ventricular outputs in postoperative cardiac surgery patients.
The purpose of this study was to determine the dynamic changes in right ventricular (RV) and left ventricular (LV) output during positive airway pressure inspiratory hold maneuvers so as to characterize the interaction of processes in creating steady-state cardiac output during positive pressure ventilation. ⋯ Positive pressure inspiration induces time-dependent changes in central hemodynamics, which are dissimilar between RV and LV function. Initially, inspiration increases RV output but decreases LV output, such that intrathoracic blood volume increases. However, sustained inspiratory pressures induce proportionally similar decreases in both RV and LV outputs. Thus, the hemodynamic effects of positive pressure ventilation will depend on the degree of lung inflation, the inspiratory time, and when measurements are made within the ventilatory cycle. These data also suggest that positive pressure ventilation with up to 20 cm H2) P(aw) does not significantly impair ventricular performance in humans.
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Journal of critical care · Jun 1997
Randomized Controlled Trial Comparative Study Clinical TrialGastric intramucosal pH changes after volume replacement with hydroxyethyl starch or crystalloid in patients undergoing elective abdominal aortic aneurysm repair.
Gastric intramucosal pH (pHi), a surrogate marker of tissue oxygenation, falls following abdominal aorta aneurysm (AAA) repair. We tested the hypothesis that volume replacement with a hydroxyethyl starch solution would result in better preserved splanchnic oxygenation than would volume replacement with crystalloid solutions. ⋯ In patients undergoing major surgery, volume resuscitation with hydroxyethyl starch solutions may improve microvascular blood flow and tissue oxygenation.
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Journal of critical care · Jun 1997
Changes in the lung after prolonged positive pressure ventilation in normal baboons.
The effects of prolonged positive pressure ventilation on lung ultrastructure are not well defined in primates. This study was designed to measure cardiopulmonary and morphological responses to 4 days of positive pressure ventilation in normal baboons. ⋯ Four days of positive pressure ventilation decreases lung compliance and worsens gas exchange by increasing shunt and VA/Q mismatch in healthy baboons. These effects are accompanied by only minor ultrastructural changes and mild inflammatory responses in the lung.
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Journal of critical care · Jun 1997
Comparative StudyEndotoxin-induced ileal Vo2-Do2 alterations do not correlate with the severity of ileal injury.
Altered Vo2-Do2 relationships are most often noted to occur in the setting of sepsis or endotoxin (LPS)-induced systemic organ microvascular injury and are generally thought to be causally linked to that injury. However, we have recently shown that ileal microvascular injury is not associated with altered ileal Vo2-Do2, relationships. Thus, we hypothesized that the severity of LPS-induced systemic organ microvascular injury would not correlate with the development of systemic organ Vo2-Do2 alterations. ⋯ Taken together, these data suggest that factors other than organ injury, as assessed by morphological and permeability alterations, are important in the pathogenesis of altered systemic organ Vo2-Do2 relationships after LPS.
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Journal of critical care · Jun 1997
Comparative StudyIncreased plasma concentrations of brain natriuretic peptide in patients with acute lung injury.
This study was performed to elucidate the pathophysiological role of brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) in acute lung injury. ⋯ These findings suggest that circulating BNP plays an important role in acute lung injury along with ANP as a compensatory mechanism for cardiac dysfunction accompanied by increased systemic vascular resistance index and pulmonary vascular resistance index. Circulating BNP may be a sensitive humoral marker for the degree of ventricular dysfunction associated with acute lung injury.