摘要:

ObjectiveThis study was designed to compare the effects of vasopressin vs. epinephrine vs. the combination of epinephrine with vasopressin on vital organ blood flow and return of spontaneous circulation in a pediatric porcine model of asphyxial arrest.DesignProspective, randomized laboratory investigation using an established porcine model for measurement of hemodynamic variables, organ blood flow, blood gases, and return of spontaneous circulation.SettingUniversity hospital laboratory.SubjectsEighteen piglets weighing 8–11 kg.InterventionsAsphyxial cardiac arrest was induced by clamping the endotracheal tube. After 8 mins of cardiac arrest and 8 mins of cardiopulmonary resuscitation, a bolus dose of either 0.8 units/kg vasopressin (n = 6), 200 &mgr;g/kg epinephrine (n = 6), or a combination of 45 &mgr;g/kg epinephrine with 0.8 units/kg vasopressin (n = 6) was administered in a randomized manner. Defibrillation was attempted 6 mins after drug administration.Measurements and Main ResultsMean ± sem coronary perfusion pressure, before and 2 mins after drug administration, was 13 ± 2 and 23 ± 6 mm Hg in the vasopressin group; 14 ± 2 and 31 ± 4 mm Hg in the epinephrine group; and 13 ± 1 and 33 ± 6 mm Hg in the epinephrine-vasopressin group, respectively (p= NS). At the same time points, mean ± sem left ventricular myocardial blood flow was 44 ± 31 and 44 ± 25 mL·min−1·100 g−1in the vasopressin group; 30 ± 18 and 233 ± 61 mL·min−1·100 g−1in the epinephrine group; and 36 ± 10 and 142 ± 57 mL·min−1·100 g−1in the epinephrine-vasopressin group (p< .01 epinephrine vs. vasopressin;p< .02 epinephrine-vasopressin vs. vasopressin). Total cerebral blood flow trended toward higher values after epinephrine-vasopressin (60 ± 19 mL·min−1·100 g−1) than after vasopressin (36 ± 17 mL·min−1·100 g−1) or epinephrine alone (31 ± 7 mL·min−1·100 g−1;p= .07, respectively). One of six vasopressin, six of six epinephrine, and four of six epinephrine-vasopressin-treated animals had return of spontaneous circulation (p< .01, vasopressin vs. epinephrine).ConclusionsAdministration of epinephrine, either alone or in combination with vasopressin, significantly improved left ventricular myocardial blood flow during cardiopulmonary resuscitation. Return of spontaneous circulation was significantly more likely in epinephrine-treated pigs than in animals resuscitated with vasopressin alone.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundHyperlactatemia is a prominent feature of cardiogenic shock. It can be attributed to increased tissue production of lactate related to dysoxia and to impaired utilization of lactate caused by liver and tissue underperfusion. The aim of this prospective observational study was to determine the relative importance of these mechanisms during cardiogenic shock.PatientsTwo groups of subjects were compared: seven cardiac surgery patients with postoperative cardiogenic shock and seven healthy volunteers.MethodsLactate metabolism was assessed by using two independent methods: a) a pharmacokinetic approach based on lactate plasma level decay after the infusion of 2.5 mmol·kg−1of sodium lactate; and b) an isotope dilution technique for which the transformation of [13C]lactate into [13C]glucose and13CO2was measured. Glucose turnover was determined using 6,62H2-glucose.ResultsAll patients suffered from profound shock requiring high doses of inotropes and vasopressors. Mean arterial lactate amounted to 7.8 ± 3.4 mmol·L−1and mean pH to 7.25 ± 0.07. Lactate clearance was not different in the patients and controls (7.8 ± 3.4 vs. 10.3 ± 2.1 mL·kg−1·min−1). By contrast, lactate production was markedly enhanced in the patients (33.6 ± 16.4 vs. 9.6 ± 2.2 &mgr;mol·kg−1·min−1;p< .01). Exogenous [13C]lactate oxidation was not different (107 ± 37 vs. 103 ± 4 mmol), and transformation of [13C]lactate into [13C]glucose was not different (20.0 ± 13.7 vs. 15.2% ± 6.0% of exogenous lactate). Endogenous glucose production was markedly increased in the patients (1.95 ± 0.26 vs. 5.3 ± 3.0 mg·kg−1·min−1;p< .05 [10.8 ± 1.4 vs. 29.4 ± 16.7 &mgr;mol·kg−1·min−1]), whereas net carbohydrate oxidation was not different (1.7 ± 0.5 vs. 1.3 ± 0.3 mg·kg−1·min−1[9.4 ± 2.8 vs. 7.2 ± 1.7 &mgr;mol·kg−1·min−1]).ConclusionsHyperlactatemia in early postoperative cardiogenic shock was mainly related to increased tissue lactate production, whereas alterations of lactate utilization played only a minor role. Patients had hyperglycemia and increased nonoxidative glucose disposal, suggesting that glucose-induced stimulation of tissue glucose uptake and glycolysis may contribute significantly to hyperlactatemia.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ObjectivesDopamine is often used in the treatment of traumatic brain injury to maintain cerebral perfusion pressure. However, it remains unclear whether dopamine contributes to secondary brain injury caused by vasoconstriction and resulting diminished cerebral perfusion. The present study investigated the effects of dopamine in different concentrations on posttraumatic cortical cerebral blood flow (CBF), brain edema formation, and cerebrospinal fluid concentrations of glutamate and hypoxanthine.DesignRandomized, placebo-controlled trial.SettingAnimal laboratory.SubjectsEighteen male Sprague-Dawley rats subjected to a focal cortical brain injury.InterventionsFour hours after controlled cortical impact, rats were randomized to receive physiologic saline solution (n = 6), 10–12 &mgr;g/kg/min dopamine (n = 6), or 40–50 &mgr;g/kg/min dopamine (n = 6), for 3 hrs. Cortical CBF was measured over both hemispheres by using laser-Doppler flowmetry before trauma and before, during, and after the infusion period. At 8 hrs after trauma, brains were removed to determine hemispheric swelling and water content. Cisternal cerebrospinal fluid was sampled to measure glutamate and hypoxanthine.Measurements and Main ResultsAfter trauma, cortical CBF was significantly decreased by 46% within the vicinity of the cortical contusion in all rats. Infusion of saline and 10–12 &mgr;g/kg/min dopamine did not change mean arterial blood pressure (MABP) or cortical CBF. However, infusion of 40–50 &mgr;g/kg/min dopamine, which elevated MABP from 89 to 120 mm Hg, significantly increased posttraumatic CBF within and around the contusion by 35%. Over the nontraumatized hemisphere, CBF remained unchanged. Hemispheric swelling, water content, cerebrospinal fluid glutamate, and hypoxanthine levels were not affected by dopamine in the given dosages.ConclusionsUnder the present study design, there was no evidence for a dopamine-mediated vasoconstriction, because posttraumatic cortical CBF was increased by dopamine-induced elevation of MABP. However, the increase in CBF did not significantly affect edema formation or cerebrospinal fluid glutamate and hypoxanthine levels.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ObjectiveIn septic shock, decreased splanchnic blood flow is reported, despite adequate systemic hemodynamics.N-acetylcysteine (NAC) was found to increase hepatosplanchnic blood flow in experimental settings. In septic shock patients, NAC improved the clearance of indocyanine green and the relationship of systemic oxygen consumption to oxygen demand. We investigated the influence of NAC on liver blood flow, hepatosplanchnic oxygen transport-related variables, and liver function during early septic shock.DesignProspective, randomized, double-blind study.SettingSeptic shock patients admitted to an interdisciplinary surgical intensive care unit.PatientsWe examined 60 septic shock patients within 24 hrs after onset of sepsis. They were conventionally resuscitated with volume and inotropes and were in stable condition. A gastric tonometer was inserted into the stomach and a catheter into the hepatic vein. Microsomal liver function was assessed by using the plasma appearance of monoethylglycinexylidide (MEGX).InterventionsSubjects randomly received either a bolus of 150 mg/kg iv NAC over 15 mins and a subsequent continuous infusion of 12.5 mg/kg/hr NAC over 90 mins (n = 30) or placebo (n = 30).Measurements and Main ResultsMeasurements were performed before (baseline) and 60 mins after beginning the infusion (infusion). After NAC, a significant increase in absolute liver blood flow index (2.7 vs. 3.3 L/min/m2;p= .01) and cardiac index (5.0 vs. 5.7 L/min/m2;p= .02) was observed. Fractional liver blood flow index (cardiac index-related liver blood flow index) did not change. The difference between arterial and gastric mucosal carbon dioxide tension decreased (p= .05) and MEGX increased (p= .04). Liver blood flow index and MEGX correlated significantly (rs= .57;p≤ .01).ConclusionsAfter NAC treatment, hepatosplanchnic flow and function improved and may, therefore, suggest enhanced nutritive blood flow. The increase of liver blood flow index was not caused by redistribution to the hepatosplanchnic area, but by an increase of cardiac index. Because of its correlation with liver blood flow index, MEGX may be helpful in identifying patients who benefit from NAC treatment in early septic shock.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ObjectiveTo determine the utilization of a portable computed tomography (CT) scanner for critically ill adult patients in an intensive care unit (ICU).DesignSurvey study and retrospective review.SubjectsCritical care attending staff and fellows and neurosurgery residents.SettingA university hospital and Level I trauma center with a multitrauma ICU, a neurotrauma ICU, and a neurosurgical ICU.InterventionsWe surveyed all physicians who ordered portable CT scans from December 1996 through June 1998. Ordering physicians included critical care attending staff and fellows (anesthesiology, surgery, internal medicine) and neurosurgery residents. Physicians who no longer worked at the institution were contacted by mail or fax. Radiology records were reviewed to determine the actual number and type of scans performed.Measurements and Main ResultsThe survey response was 100%. Most physicians reported ordering portable head CT scans (97%), followed by chest CT (88%), abdominal CT (78%), and pelvic CT (34%) scans. Analysis of the actual number of scans performed correlated with these reports (511 head, 115 chest, 88 abdomen, and 87 pelvis). The indication for portable CT scans (as opposed to a “fixed” or “stationary” scans) cited most often was patient severity of illness (77%). Patients on extracorporeal support (93%), those with cardiovascular instability (70%), followed by those with respiratory instability (57%) and neurologic instability (40%) were deemed too ill to transport. If the portable CT scanner was unavailable, however, most physicians (67%) ordered a fixed helical CT scan and the patient was transported to the radiology suite, regardless of medical condition.ConclusionsAccess to a portable CT scanner impacts the physician ordering patterns for ICU patients. We found that 100% of surveyed physicians used the portable CT scanner for critically ill patients when the patient was unstable. If the diagnostic study was deemed medically necessary, and the portable scanner was unavailable, most surveyed physicians ordered a “fixed” helical scan and the patient was transported by an experienced transport team for the study. The portable CT offered an alternative and potentially safer means of obtaining diagnostic studies.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ObjectiveTo determine blood and lung alveolar concentrations of interleukin (IL)-2 in acute respiratory distress syndrome (ARDS) and their relationship with polymorphonuclear neutrophil (PMN) apoptosis and patient survival.DesignProspective cohort study.SettingMedical and surgical intensive care units (ICUs; Canada) and the intensive care department (Belgium).PatientsNineteen consecutive patients with ARDS, 14 non-ARDS ICU patients, and 20 healthy volunteers.InterventionsBlood samples and bronchoalveolar lavages (BAL) obtained via venous puncture and by fiberoptic bronchoscopy in the first 72 hrs after the onset of ARDS.Measurements and Main ResultsOne early point concentration of IL-2 was measured in both blood and BAL fluids of the three groups.In vivoalveolar PMN apoptotic index in BAL fluids and the influence of BAL fluid exposure on normal blood PMN spontaneous apoptosisin vitrowere evaluated. Blood IL-2 was significantly lower in patients with ARDS compared with non-ARDS ICU patients and controls. In contrast, IL-2 in BAL fluids of patients with ARDS was dramatically elevated compared with non-ARDS ICU patients and controls. ARDS survivors exhibited lower early IL-2 blood levels than nonsurvivors and generally had a higher IL-2 lung content. Lung alveolar PMN apoptosisin vivowas lower in patients with ARDS in comparison with controls. This apoptotic index was correlated with corresponding IL-2 alveolar levels in patients with ARDS. Exposure of normal blood PMN to BAL fluids from patients with ARDS delayed apoptosisin vitro. Immunodepletions of IL-2, granulocyte-macrophage colony stimulating factor, and a combination of both cytokines from BAL fluids of ARDS patients significantly restored PMN apoptosis. The recovery of PMN apoptosis was more effective when IL-2 was depleted in BAL fluids from ARDS survivors compared with nonsurvivors.ConclusionsOpposite and disproportional concentrations of IL-2 are observed in blood and lung fluids of patients with early ARDS. IL-2 significantly contributes (with granulocyte-macrophage colony stimulating factor) to the inhibition of PMN apoptosis in BAL fluids of patients with ARDS. Early low blood IL-2 and high IL-2-driven inhibition of PMN apoptosis are beneficial to survivors. Thus, IL-2 is a new candidate for monitoring in early ARDS and an interesting indicator of prognosis.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID