The Journal of surgical research
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Adrenergic agents (AAs) have been used in critically ill patients to increase oxygen delivery (DO2). Associated parallel increases in oxygen consumption (VO2) have been noted and are thought to represent improved tissue oxygen utilization at supraphysiologic levels of DO2. We hypothesize that the increase in VO2 associated with the use of AAs in septic animals is secondary to direct, obligate, metabolic effects of the agents themselves. ⋯ Dobutamine increased VO2 to 119% of baseline (31% above control) and dopamine to 111% of baseline (28% over control). We conclude that adrenergic agents cause a significant increase in whole body VO2 at moderate doses in septic dogs. It is likely, therefore, that the "pathologic" relationship between VO2 and DO2 described in critically ill patients is partially due to the direct metabolic effects of AAs.
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Although impairment of vascular smooth muscle contractility occurs during the late stages of polymicrobial sepsis, it is not known whether this also occurs in early stages of sepsis and, if so, whether different mechanisms are responsible for such smooth muscle dysfunction. To determine this, rats were subjected to sepsis by cecal ligation and puncture (CLP). Immediately following CLP or sham operation, all animals received 3 ml/100 g body wt normal saline. ⋯ Endothelium removal at 10 hr after CLP restored the contraction induced by NE and KCl to sham levels. In contrast, the smooth muscle contractile dysfunction, observed during late sepsis (35 hr post-CLP), was not restored by the removal of endothelium. Thus, the smooth muscle impairment, observed in early sepsis, is due to mediators released from septic endothelium.(ABSTRACT TRUNCATED AT 250 WORDS)
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Estimation of blood flow in the microcirculation is essential in the analysis of the events that occur during organ ischemia and subsequent reperfusion. In this study the use of laser-Doppler flowmetry is evaluated as a method for studying liver blood flow in the rat using an in vivo ischemia-reperfusion model. The experimental procedure consists of the temporary interruption of blood flow to the left lateral and medial lobes of the liver and subsequent recording of the postischemic liver blood flow using a laser-Doppler flowmeter. ⋯ The reperfusion records showed a biphasic curve with a mean flow of 59.6% of the baseline after 30 min of ischemia and of 38.3 and 41.1% after 45 and 60 min of ischemia, respectively. There were statistically significant differences between all the groups and the controls, and between 45 and 30 min of ischemia but not between 45 and 60 min. This is a useful model for studying ischemic liver injury in the rat.
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Gastric mucosal injury after hemorrhagic shock may be a consequence of both ischemia and reperfusion, as toxic oxygen-derived compounds are generated when ischemic tissues are reperfused. The present study was designed to estimate the magnitude of the reperfusion component of gastric mucosal injury, in comparison with the known capacity of the gastric mucosal surface to rapidly restore or restitute its surface after removal of various insults. Twelve dogs were subjected to 2 hr of hemorrhagic shock, with intragastric acid infused to produce gastric mucosal injury. ⋯ Particularly in the antrum, the resuscitated animals had significantly less gastric mucosal injury than unresuscitated animals. The amount of gastric mucosal injury was strongly inversely related to the success of resuscitation after 2 hr, specifically correlating with left ventricular pressure, cardiac index, mean arterial pressure, and systemic pH. Our data suggest that gastric mucosal restitution rather than reperfusion injury may predominant within a few hours of hemorrhagic shock and show that the degree of shock-induced gastric mucosal injury is inversely related to hemodynamic performance after resuscitation.
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Bronchopulmonary injury secondary to smoke inhalation is a significant comorbid factor following major thermal trauma. The present study evaluates the effects of pentoxifylline (PTX) on pulmonary function in an ovine model of inhalation injury. Following smoke exposure to produce a moderate inhalation injury, 16 animals were divided into two groups. ⋯ Extravascular lung water and decrease in lung compliance were greater in Group 1. There was less morphologic evidence of airway injury in Group 2 compared to Group 1. The improvement of pulmonary function following treatment with PTX suggests that this agent may be useful in the management of smoke inhalation injury.