摘要:

ObjectiveVasopressor agents and mechanical ventilation are routine interventions for the treatment of sepsis complicated by hypotension. It was our hypothesis that such treatment singly or in combination increases the duration of survival.DesignProspective, randomized, controlled study.SettingUniversity research laboratory.SubjectsThirty male Sprague-Dawley rats anesthetized with intraperitoneal injection of pentobarbital.InterventionsPeritonitis was induced by cecal ligation and spillage of cecal contents into the abdominal cavity. The first phase of this study was performed on 15 spontaneously breathing Sprague-Dawley rats that were randomized to three groups of five animals each. One group received treatment with dopamine. The second group received norepinephrine. The third group received only the diluent as a placebo. Concentrations of the vasopressor agents were increased such that mean arterial pressure was maintained at approximate 80% of baseline values; the volumes infused were kept constant. For the second phase of this study, the grouping of animals and the techniques of study were identical, except that rats were mechanically ventilated.Measurements and Main ResultsMean arterial pressure was best maintained with norepinephrine. However, no statistically significant differences in duration of survival, cardiac index, arterial blood lactate concentration, or arterial and venous PCO2and PO2values were identified between groups.With mechanical ventilation, survival was prolonged (p less than .01). Survival was increased from an average of 291 mins to 342 mins with dopamine, from 257 mins to 352 mins in placebo controls, and from 280 mins to 329 mins with norepinephrine. Again, no significant differences in hemodynamic and blood gas measurements, or in the duration of survival between vasopressor-treated and control animals were documented.ConclusionsNo benefit or detriment was demonstrated when vasopressor agents were administered to sustain arterial pressure in the course of experimental peritonitis in this murine model of septic shock. This finding contrasted with highly significant prolongation of survival when animals were mechanically ventilated. There was no evidence that routine vasopressor therapy, under these controlled experimental conditions in rats, improved duration of survival.(Crit Care Med 1996; 24:125-130)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo test whether renal excretory function decreases after nitric oxide synthase inhibition during experimental hyperdynamic sepsis.DesignProspective, randomized, controlled animal trial.SettingResearch laboratory at a large university medical center.SubjectsChronically instrumented Merino breed ewes (n equals 18).InterventionsContinuous infusion of Escherichia coli endotoxin (10 ng/kg/min) for the experimental period of 32 hrs. One group received a bolus of the nitric oxide synthase inhibitor, Nomega-nitro-L-arginine methyl ester (25 mg/kg), after 24 hrs, and the remaining sheep were given the carrier, sodium chloride 0.9%.Measurements and Main ResultsThe sheep developed a hyperdynamic cardiovascular response characterized by a decrease in systemic vascular resistance index (p less than .05), and an increased cardiac index (p less than .05) by 24 hrs. The sheep retained fluid, with creatinine clearance decreasing in the presence of chronically increased atrial natriuretic peptide. After the administration of Nomega-nitro-L-arginine methyl ester, systemic vascular resistance index and cardiac index returned to baseline values, fluid balance normalized, and glomerular filtration rate increased (p less than .05), while the control animals continued to retain fluid and their creatinine clearance continued to decrease. The concentrations of atrial natriuretic peptide did not differ significantly between groups after Nomega-nitro-L-arginine methyl ester administration.ConclusionsIn this ovine model of experimental hyperdynamic sepsis, renal excretory function decreases in the presence of chronically increased concentrations of atrial natriuretic peptide. Administration of the nitric oxide synthase inhibitor, Nomega-nitro-L-arginine methyl ester, reverses the vasodilatory state, thereby improving fluid balance and glomerular filtration.(Crit Care Med 1996; 24:131-136)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectivesDiaspirin crosslinked hemoglobin is a resuscitative solution with excellent oxygen-carrying capacity. Diaspirin crosslinked hemoglobin produces an immediate increase in blood pressure and marked regional circulatory changes in rats and pigs. Our objective was to determine the role of endothelin in the cardiovascular actions of diaspirin crosslinked hemoglobin (modified) and (unmodified) stroma reduced hemoglobin solutions.DesignProspective, randomized comparison of cardiovascular effects of diaspirin crosslinked and stroma reduced hemoglobin in control rats and in rats pretreated with cyclo(D-Asp-Pro-D-Val-Leu-D-Trp) (BQ-123), an endothelin-A receptor antagonist.SettingResearch laboratory.SubjectsMale Sprague-Dawley rats.InterventionsModified, highly purified, and heat pasteurized (diaspirin crosslinked) and unmodified (stroma reduced) hemoglobin in control (untreated) and BQ-123 (5 mg/kg/hr iv)-treated rats.Measurements and Main ResultsInfusion of stroma reduced hemoglobin (400 mg/kg iv) in control rats produced an increase in blood pressure (43%) and total peripheral resistance (65%) without any change in heart rate, cardiac output, and stroke volume. Stroma reduced hemoglobin decreased blood flow to the kidneys and liver, increased blood flow to the heart, and had no effect on blood flow to the brain, gastrointestinal tract, spleen, musculoskeletal system, skin, and mesentery and pancreas. Infusion of stroma reduced hemoglobin in rats treated with BQ-123 (5 mg/kg/hr iv) increased the blood pressure to a similar degree when compared with control rats, but the increase in total peripheral resistance was significantly attenuated. The stroma reduced hemoglobin-induced decrease in blood flow to the kidneys and liver was significantly attenuated in BQ-123-treated rats as compared with control rats. However, the stroma reduced hemoglobin-induced increase in blood flow to the heart of BQ-123-treated rats was similar to the increase in control rats. Infusion of diaspirin crosslinked hemoglobin (400 mg/kg iv) produced increases in blood pressure (81%), cardiac output (36%), stroke volume (30%), and total peripheral vascular resistance (45%), along with increases in blood flow to the heart, spleen, gastrointestinal tract, and skin of control rats. The blood flows to the brain, kidneys, liver, musculoskeletal system, and mesentery and pancreas were not altered by diaspirin crosslinked hemoglobin in control rats. The increases in blood pressure, cardiac output, stroke volume, and total peripheral vascular resistance by diaspirin crosslinked hemoglobin were significantly blocked in BQ-123-treated rats as compared with control rats. The increases in blood flow to the heart, spleen, and skin by diaspirin crosslinked hemoglobin were significantly blocked in BQ-123-treated rats as compared with control rats. Diaspirin crosslinked hemoglobin produced an increase in the blood flow to the brain and a decrease in blood flow to the kidney and musculoskeletal system of BQ-123-treated rats as compared with control rats. Blood plasma endothelin-1-like immunoreactivity was found to be significantly increased after treatment with diaspirin crosslinked hemoglobin or stroma reduced hemoglobin.ConclusionsThe endothelin-A receptor antagonist, BQ-123, could attenuate the systemic hemodynamic and regional circulatory effects of diaspirin crosslinked hemoglobin and stroma reduced hemoglobin. However, the increase in blood flow to the heart induced by stroma reduced hemoglobin could not be attenuated by BQ-123.(Crit Care Med 1996; 24:137-147)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo examine the pulmonary and cardiac function of children who survived an episode of acute hypoxemic respiratory failure.DesignDescriptive cohort analysis.SettingPediatric clinical research center of a university hospital.PatientsUtilizing the criteria of PaO2less than 75 torr (less than 10 kPa) with an FIO2of more than 0.5 while intubated, bilateral diffuse pulmonary infiltrates on chest radiograph, and exclusion of cardiogenic pulmonary edema, 147 patients were identified during the 6-yr period from July 1, 1986 to August 1, 1993. Fifty patients survived to discharge and 37 were alive at the time of follow-up. Fourteen patients were eventually entered into the study.InterventionsThe study patients were given a test battery consisting of a questionnaire specific for cardiopulmonary status, a physical examination, a chest radiograph, electrocardiography, echocardiography with detailed examination of the pulmonary circulation, pulse oximetry, complete blood count, and serum chemistries and pulmonary function testing with bronchoprovocation in selected patients.Measurements and Main ResultsThe 14 follow-up patients were evaluated an average of 23 plus minus 23 months (range 3 to 66) following intensive care unit discharge. No child reported a significant alteration in lifestyle or limitation of activities. Physical examinations were generally unremarkable. The room air oxyhemoglobin saturation was more than equals 0.98 in all patients. Comparison of chest radiographs at the time of follow-up with those chest radiographs during the period of critical illness showed marked but not complete improvement in all. Electrocardiograms and echocardiograms showed new evidence of left ventricular hypertrophy in one child. The right ventricular preejection period to ejection time ratio was normal in all subjects. Eleven patients completed spirometry. Four patients were normal and the other patients had evidence of restrictive or obstructive disease either at baseline or after bronchoprovocation challenge. Ten children had lung volume measurements. Five children were normal, two showed increased volumes consistent with obstruction, and three showed decreased volumes indicative of restriction. Four of seven patients showed evidence of decreased diffusion capacity. Six of seven patients with evidence of abnormal pulmonary function had a positive response to bronchodilator administration.ConclusionsAlthough pediatric survivors of acute hypoxemic respiratory failure perceive neither a limitation in lifestyle nor chronic pulmonary morbidity, careful examination of the cardiopulmonary system demonstrates a significant number with abnormal chest radiographs and abnormalities in pulmonary function. These children require careful follow-up and may benefit from use of a bronchodilator.(Crit Care Med 1996; 24:148-154)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Objectivesa) To determine if cerebral blood flow is symmetric after internal carotid artery and ipsilateral internal jugular vein ligation in infants during venoarterial extracorporeal life support. b) To determine the cerebral CO2reactivity (open triangle cerebral blood flow/open triangle torr CO2) of neonates during venoarterial extracorporeal life support and its correlation to neurodevelopmental outcome.DesignProspective, clinical study.SettingUniversity hospital pediatric intensive care unit.PatientsFourteen neonates with respiratory failure who were receiving venoarterial extracorporeal life support.InterventionsPaCO2was altered by adjusting the CO2gas flow through the membrane oxygenator. Cerebral blood flow was measured over both parietal-temporal regions at three PaCO2values using xenon-133 clearance methodology. Cerebral blood flow measurements were made early (less than equals 12 hrs of extracorporeal life support, n equals 10) or late (more than equals 48 hrs of extracorporeal life support, n equals 10). In six of 14 infants, both early and late cerebral blood flow rates were measured. PaO2, mean arterial pressure, pump flow rate, and temperature were stable during each study period. Neurodevelopmental outcome was assessed in the neonatal follow-up clinic.Measurements and Main ResultsRight and left hemispheric cerebral blood flow rates were significantly correlated with each other during early and late extracorporeal life support (p equals .0001; r2equals .91). Overall, hemispheric cerebral blood flow was statistically symmetric. There was no association of CO2reactivity (open triangle cerebral blood flow/open triangle torr PCO2, range 0.04 to 1.36 mL/min/100 g/torr) with short-term neurodevelopmental outcome. Infants with normal neurodevelopmental outcome had variable CO2reactivity (range 0.04 to 0.67 mL/min/100 g/torr). Normal short-term neurodevelopmental outcome was observed in two infants with cerebral blood flow of less than 10 mL/min/100 g.ConclusionsHemispheric cerebral blood flow was symmetric in infants during early and late venoarterial extracorporeal life support. Some subgroups showed a trend toward decreased right hemispheric cerebral blood flow, but the small number of patients limited interpretation of this finding. CO2reactivity and cerebral blood flow were highly variable in this population, and were not predictive of short-term neurodevelopmental outcome. Stressed neonates with extremely low cerebral blood flow rates may have relatively normal short-term neurodevelopmental outcome after venoarterial extracorporeal life support.(Crit Care Med 1996; 24:155-162)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectivesThe systemic inflammatory response syndrome (SIRS) is the massive inflammatory reaction resulting from systemic mediator release that may lead to multiple organ dysfunction. The objective of this review article is to analyze the roles of cytokines, cytokine production, and the relationship of cytokine production to the development of SIRS.Data SourcesPrevious research and clinical studies related to cytokines and their relationship to SIRS.Study SelectionFrom the studies reviewed, three critical questions are addressed. First, what is the definition of increased cytokine concentrations? Second, what other systemic illnesses besides sepsis can alter cytokine concentrations? Third, what are the right cytokines to measure?Data SynthesisThis article postulates a three-stage development of SIRS, in which stage 1 is a local production of cytokines in response to an injury or infection. Stage 2 is the protective release of a small amount of cytokines into the body's circulation. Stage 3 is the massive systemic reaction where cytokines turn destructive by compromising the integrity of the capillary walls and flooding end organs.ConclusionsWhile cytokines are generally viewed as a destructive development in the patient that generally leads to multiple organ dysfunction, cytokines also protect the body when localized. It will be necessary to study the positive effects of cytokines while also studying their role in causing SIRS. It will also be important to investigate the relationship between cytokines and their blockers in SIRS.(Crit Care Med 1996; 24:163-172)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID