ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo assess the hemodynamic effects of fluid loading in patients with acute circulatory failure caused by acute massive pulmonary embolism (AMPE).DesignProspective study.SettingRespiratory critical care unit of a university hospital.PatientsThirteen patients free of previous cardiopulmonary disease with angiographically proven AMPE (Miller index = 24 +/- 1), with acute circulatory failure defined by a cardiac index (CI) lower than 2.5 L/min/m2.InterventionInfusion of 500 mL of dextran 40 over 20 mins.Measurements and Main ResultsFluid loading induced a substantial increase in right atrial pressure from 9 +/- 1 mm Hg to 17 +/- 1 mm Hg and in right ventricular end-diastolic volume index from 123 +/- 14 mL/m2to 150 +/- 11 mL/m2(p < .05 for both comparisons). The increase in right ventricular preload was associated with an increase in CI from 1.6 +/- 0.1 to 2.0 +/- 0.1 L/min/m2(p < .05), whereas right ventricular ejection fraction (15 +/- 3% at baseline vs. 16 +/- 3% after fluid loading) and total pulmonary vascular resistance index (1689 +/- 187 dyne[center dot]sec/cm5[center dot]m2at baseline vs. 1492 +/- 166 dyne[center dot]sec/cm (5) [center dot]m2after fluid loading) remained unchanged. The increase in CI induced by fluid loading was inversely correlated to baseline right ventricular end-diastolic volume index (r = -.89; p < .05).ConclusionsThese results suggest that fluid loading can improve hemodynamic status in patients with acute circulatory failure caused by AMPE. (Crit Care Med 1999; 27:540-544)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo determine the influence of methylprednisolone on the cytokine balance during cardiac surgery.DesignProspective, randomized, nonblinded study.SettingUniversity hospital.PatientsTwenty-one patients on cardiopulmonary bypass undergoing aortocoronary bypass surgery.InterventionsAccording to a randomized sequence, the patients either received methylprednisolone (30 [micro sign]g/kg) before cardiopulmonary bypass and before declamping of the aorta (MPS group, n = 11) or received nothing (control group, n = 10).Measurements and Main ResultsSerum proinflammatory cytokines (interleukin [IL]-8, IL-6) and anti-inflammatory cytokines (IL-10, IL-1ra) were measured by enzyme-linked immunosorbent assays. Serum IL-6 and IL-8 concentrations in the control group (15.2 +/- 4.1 and 14.1 +/- 1.9 pg/mL, preoperatively) increased to 242 +/- 70.1 and 97.3 +/- 18.3 pg/mL at 60 mins after declamping of the aorta (p < .01, p < .01, respectively). The increases were greater than those from 2.5 +/- 0.6 and 2.5 +/- 0.5 pg/mL to 109.5 +/- 29.0 and 33 +/- 4.1 pg/mL in the MPS group for IL-6 and IL-8, respectively. Serum IL-10 concentrations increased significantly 60 mins after declamping of the aorta compared with its preoperative value in the two groups (the control group, from 1.0 +/- 0 to 537.9 +/- 61.7 pg/mL; the MPS group, from 0.3 +/- 0.2 to 654.9 +/- 24 pg/mL [p < .01, p < .01, respectively]). No difference was found between the two groups. Similarly, serum IL-1ra concentrations in the two groups increased the preoperative value in the control group from 304 +/- 120 to 44,374 +/- 14,631 pg/mL and in the MPS group from 616.5 +/- 109.6 to 35,598 +/- 9,074 pg/mL at 60 mins after declamping of the aorta (p < .01, p < .01, respectively). There was no difference between the two groups.ConclusionsMethylprednisolone reduces the production of IL-6 and IL-8 but not that of IL-10 and IL-1ra. These results suggest that one of the mechanisms of the cytoprotective effect of methylprednisolone may be to make changes in the proinflammatory and anti-inflammatory cytokine balance. (Crit Care Med 1999; 27:545-548)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo evaluate the performance of a newly developed assay to assess neutrophil function capacity. After optimization, the assay was performed on samples derived from patients with septic shock and compared with healthy controls and patients with a systemic viral infection.DesignProspective evaluation of the performance of a new assay.SettingsMedical intensive care unit, hospital laboratory.PatientsTen patients with septic shock, ten patients with infectious mononucleosis, and ten healthy controls.Measurements and Main ResultsWe report an assay to assess neutrophil function capacity, in which CD10 membrane expression is measured by FACS before and after in vitro stimulation with Staphylococcus aureus bacteria. This assay evaluates the early activation state of circulating neutrophils and is shown to be of value in diagnosing a sepsis syndrome. First the assay was optimized. As an anticoagulant, sodium-citrate gave the best results. Blood samples must be kept on ice to reduce activation inside the siliconized tube and can be stored in this way for at least 8 hrs without affecting the test results. Kinetic studies showed a maximal expression of CD10 on neutrophils of healthy volunteers after 15 mins of stimulation with S. aureus bacteria. Second, the test was performed on samples derived from ten septic patients and ten patients with infectious mononucleosis. Septic patients had a significantly decreased CD10 expression capacity compared with healthy controls. Patients with infectious mononucleosis have a significantly higher CD10 expression capacity compared with septic patients, but in approximately one-half of them, the expression capacity was below the range found in controls.ConclusionsThese results indicate that in circulating neutrophils, the secretory vesicles have been mobilized completely in patients with septic shock. The assay proves to be of acceptable analytical quality and can be quickly and easily performed. Regarding clinical performance, this assay may be helpful in diagnosing septic shock. (Crit Care Med 1999; 27:549-553)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo describe the incidence and causes of systemic inflammatory response syndrome (SIRS), to determine the risk factors for its development, and to assess its impact on the outcome of patients hospitalized for gastrointestinal bleeding.DesignProspective, observational study.SettingA 528-bed, university-affiliated, teaching hospital.PatientsThe study included 411 adults hospitalized for gastrointestinal bleeding from January 1, 1995, through June 30, 1996.MeasurementsWe obtained the demographic data, selected clinical findings, laboratory values, length of hospital stay, presence and cause of SIRS, presence of organ failure, and in-hospital mortality for each patient. The Acute Physiology and Chronic Health Evaluation II (APACHE II) score was calculated. Univariate and multivariate logistic regression analyses were used to determine differences between groups.ResultsPatients' ages (mean +/- SD) were 55.9 +/- 17.3 yr; 227 (55%) were male; 247 (60%) were African-American. SIRS developed in 112 patients (27%). Sepsis was the cause of SIRS in 63% of patients (70/112). Severe sepsis developed in 20 patients and septic shock in 5 patients. The most common cause of sepsis was pneumonia (19). There were no significant differences in age, gender, race, and the presence of liver disease between patients with and without SIRS. Upper gastrointestinal bleeding (76/211 vs. 36/200; p = .0196), intensive care unit admission (73/152 vs. 39/259; p < .0001), and higher APACHE II scores (median, 17 vs. 11; p < .0001) were associated with the development of SIRS. The length of hospital stay was longer (median, 9.5 vs. 3 days; p < .0001), and the number of organ failures (median, 1 vs. 0; p < .0001) and in-hospital mortality rates (23 vs. 4%; p < .0001) were higher in patients with SIRS than in those without SIRS.ConclusionsSIRS occurs in 27% of patients admitted for gastrointestinal bleeding and is associated with a poor prognosis. Intensive care unit admission, upper gastrointestinal bleeding, and high APACHE II scores are risk factors for the development of SIRS in patients hospitalized for gastrointestinal bleeding. (Crit Care Med 1999; 27:554-557)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo determine the systemic, pulmonary, mesenteric, and renal hemodynamic effects of short and prolonged infusions of dobutamine.DesignProspective randomized unblinded study.SettingUniversity research laboratory.SubjectsThirteen newborn (1-3 days old) piglets.InterventionsPiglets were instrumented and studied 48 hrs later. Fifteen-minute infusions of dobutamine at 5, 10, 20 and 50 [micro sign]g/kg[center dot]min were randomly given with 15-min rests between the doses. After a 1-hr hiatus, a dose of 10 [micro sign]g/kg[center dot]min was continuously administered for 2 hrs.Measurements and Main ResultsSystemic and pulmonary arterial pressures, cardiac index (thermodilution), and superior mesenteric and renal artery flows were measured. Vascular resistance values were calculated.Main ResultsFifteen-minute infusions: Dobutamine dose-dependently increased cardiac index with tachycardia but not stroke volume (from 187 +/- 43 to 238 +/- 51 mL/kg[center dot]min at baseline and 50 [micro sign]g/kg[center dot]min, respectively, p < .05; values expressed as mean +/- SD). Systemic, but not pulmonary, vascular resistance decreased, resulting in a significant decrease in systemic to pulmonary arterial pressure ratio (from 3.8 +/- 0.8 at baseline to 3.2 +/- 1.0 at 50 [micro sign]g/kg[center dot]min). Superior mesenteric and renal flows were not affected. Two-hour infusion at 10 [micro sign]g/kg[center dot]min: Cardiac index progressively increased from 173 +/- 34 to 240 +/- 58 mL/kg[center dot]min at baseline and 120 mins, respectively, (p < .05). The initial tachycardia was transient, and stroke volume was significantly increased at 60 mins and thereafter. Although systemic and pulmonary vascular resistance values fell simultaneously, systemic to pulmonary arterial pressure ratio decreased significantly to 3.4 +/- 0.9 at 120 mins from 3.9 +/- 0.7 at baseline. Superior mesenteric and renal artery flows increased significantly with vasodilation after 60 mins.ConclusionsShort infusions of dobutamine dose-dependently increase cardiac output due to tachycardia, without significant effect on mesenteric and renal blood flows. Prolonged infusion of dobutamine at 10 [micro sign]g/kg[center dot]min progressively increases cardiac output and stroke volume with transient tachycardia, and increases mesenteric and renal blood flows. Caution is required in the treatment of critically ill neonates with dobutamine, which could also reduce systemic to pulmonary arterial pressure ratio. (Crit Care Med 1999; 27:558-564)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo determine properties of acadesine, the prototype adenosine regulating agent, in an experimental model in which abdominal sepsis is superimposed onto hemorrhagic shock.DesignRandomized, blinded animal study.SettingUniversity-based animal research facility.SubjectsTwenty-eight anesthetized mongrel pigs (35.5 +/- 1.1 kg).InterventionsThe cecum was ligated and punctured to produce abdominal sepsis. To produce hemorrhagic shock, 45% to 47% of the estimated blood volume was withdrawn. After 1 hr, shed blood plus supplemental crystalloid (twice the shed blood volume) plus either acadesine (5 mg/kg bolus + 1 mg/kg x 60 min, n = 10) or its vehicle (n = 10) was administered. All animals were awakened and observed for 48 hrs. At 48 hrs, cardiac function, bacterial cultures from the septic focus, and inflammatory changes in the abdomen were quantified.Measurements and Main ResultsAfter resuscitation with acadesine vs. vehicle, we observed the following: a) arterial blood pressure and cardiac filling pressures were similar but cardiac index, systemic oxygen delivery, and systemic oxygen consumption were increased; b) plasma lactate was higher, systemic vascular resistance was lower, but ileal mucosal blood flow was not measurably altered; c) lipopolysaccharide-evoked tumor necrosis factor production in whole blood ex vivo was reduced; d) in those animals that survived 48 hrs (10/10 vs. 8/10), sepsis-induced cardiac depression, amount of free intraperitoneal fluid, extra abscess inflammatory reaction, abscess wall formation, abscess bacterial counts, and peritoneal bacterial counts, were all similar, but blood bacterial counts were higher.ConclusionsFluid resuscitation with acadesine produced no adverse hemodynamic consequences and probably improved washout of metabolites from the reperfused microcirculation In sites other than the small intestine or heart. Taken together, these observations suggest that adenosine regulating agents might have therapeutic potential during fluid resuscitation from trauma. However, at least in these extreme conditions, the acute salutary effects of acadesine were probably overwhelmed by polymicrobial sepsis. Further studies must determine whether supplemental adjuvants to boost host defense during recovery from trauma will optimize adenosine-based resuscitation solutions. (Crit Care Med 1999; 27:565-575)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveMultiwavelength near infrared (NIR) spectrophotometry can monitor the redox state of cytochrome a,a3 (cyt a,a3) in vivo. Because cyt a,a3 is the most immediate reductant of oxygen, this technique has been proposed to evaluate tissue oxygenation. The purpose of this study was to examine the relationship between cyt a,a3 oxidation level as an indicator of dysoxia and oxygen uptake (VO2) when oxygen delivery (DO2) was progressively lowered in an in situ vascularly isolated hindlimb.DesignProspective, randomized, laboratory study.SettingUniversity research laboratory.SubjectsFourteen pigs.InterventionsMeasurement of critical values for both VO2and cyt a,a3 oxidation during ischemic and hypoxic hypoxia.Measurements and Main ResultsThe right hindlimb of anesthetized, paralyzed, and ventilated pigs was subjected to progressive ischemic or hypoxic hypoxia for 100 mins by ten stepwise decreases in DO2. In ischemic hypoxia (n = 7), arterial inflow (Q) from a pump-membrane oxygenator system was lowered from 50 to 0 mL/min, with PaO2maintained at 100 mm Hg. In hypoxic hypoxia (n = 6), PaO2was lowered from 100 mm Hg to 0 mm Hg. Hindlimb DO2was calculated as the product of Q and arterial oxygen content, and VO2as the product of Q and arteriovenous difference. The cyt a,a3 oxidation level was measured every 10 secs with a four-wavelength spectrophotometer. These parameters were measured 9 mins after each change of DO (2). Critical values for both VO2and cyt a,a3 oxidation level as a function of DO2were determined in each animal by dual linear regression analysis. In ischemic and hypoxic hypoxia, a strong correlation was found between cyt a,a3 oxidation level and VO2in both ischemic and hypoxic hypoxia (r2= .90 and .87, respectively). Hindlimb vascular resistance increased in ischemic hypoxia and decreased in hypoxic hypoxia when DO2reached critical DO2.ConclusionsFrom these results, we concluded that monitoring the cyt a,a3 redox state by NIR spectrophotometry is, in this experimental setting, a sensitive indicator of dysoxia during regional hypoxic or ischemic hypoxia. (Crit Care Med 1999; 27:576-582)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo investigate the cardiorespiratory effects of graded bilateral pleural effusions in the anesthetized pig.DesignProspective, randomized, controlled, laboratory study.SettingAnimal laboratory.SubjectsEleven male Yorkshire pigs.InterventionsAnimals were anesthetized using inhaled isoflurane. Orotracheal intubation was followed by mechanical ventilation. Bilateral chest tubes were inserted, and graded increasing pleural effusions were created using saline of 0, 20, 40, and 80 mL/kg, divided equally between each side. At each pleural volume, intravascular volume was randomly altered (by phlebotomy or transfusion of colloid) to normal (unchanged), low (decreased by 10 mL/kg), or high (increased by 10 mL/kg).Measurements and Main ResultsHemodynamic parameters, intrapleural pressures, hemoglobin, and blood gases were measured. At the lowest volume of pleural fluid, PaO2was reduced by approximately 50% vs. baseline, whereas systemic hemodynamics were unchanged. PaO2was reduced in a dose-dependent fashion as pleural volume increased but was not affected by alterations in intravascular volume. Intrapulmonary shunt was increased both by intrapleural volume in a dose-dependent fashion and by increases in intravascular volume at high levels of pleural volume. Cardiac output and systemic mean arterial pressure increased with elevated intravascular volume but were not influenced by lower levels of intrapleural volume. Mean pulmonary arterial pressure, central venous pressure, and pulmonary artery occlusion pressure were increased by elevations in both intrapleural volume and intravascular volume. Intrapleural pressure and pulmonary vascular resistance were related to intrapleural volume only.ConclusionsHypoxemia occurs as an early event in acute bilateral pleural effusions and precedes hemodynamic decompensation. Oxygenation is independent of intravascular filling pressures, but hemodynamics are preserved with elevated filling pressures. Clinical studies should be undertaken to examine the risks/benefits of careful removal of pleural fluid in patients with pleural effusions, when oxygenation is impaired during mechanical ventilation. (Crit Care Med 1999; 27:583-587)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID