摘要:

ObjectiveTo compare the safety and effectiveness of propofol (2,6-diisopropylphenol) to midazolam for sedation of mechanically ventilated patients after coronary artery bypass grafting.DesignOpen, randomized, prospective trial.SettingCardiothoracic intensive care unit (ICU), Cleveland Clinic Foundation.PatientsEighty-four patients with normal or moderately impaired left ventricular function who underwent elective coronary artery bypass graft surgery under high-dose opioid anesthesia.InterventionsPatients were randomly selected to receive either propofol (mean loading dose 0.24 mg/kg; mean maintenance dose 0.76 mg/kg/hr) or midazolam (mean loading dose 0.012 mg/kg; mean maintenance dose 0.018 mg/kg/hr). Infusion rates were titrated to keep patients comfortable, drowsy, and responsive to verbal stimulation. Study duration, 8 to 12 hrs; infusions were started in the ICU when patients were awake and hemodynamically stable.Measurements and Main ResultsDuring therapy, both groups had lower mean arterial pressures and heart rates compared with baseline measurements; however, the propofol group had significantly lower heart rates than the midazolam group during the first 2 hrs of infusion. The propofol group also had significantly lower blood pressure measurements 5 and 10 mins after the initial dose, although there was no difference during infusion. Baseline cardiac output was measured before starting the infusion, and measurements were repeated during continuous infusion at 4, 8, and 12 hrs. Cardiac output values were similar. Propofol maintenance infusions ranged from 3 to 30 μg/kg/min and midazolam infusions ranged from 0.1 to 0.7 μg/kg/min. At these infusion rates. both groups had adequate sedation, based on nurse and patient evaluations; however, the propofol group used significantly lower total doses of sodium nitroprusside and supplemental opioids.ConclusionsBoth propofol and midazolam provided safe and effective sedation of coronary artery bypass graft patients recovering from high-dose opioid anesthesia. The reduced need for both antihypertensive medication and opioids seen in the propofol group may be advantageous. However, the hypotension seen after the initial bolus dose of propofol may be a concern. No difference between the two drugs could be demonstrated in time to extubation or ICU discharge, although it is probable that time to extubation was governed more by residual operative opioids than the study agents. (Crit Care Med 1994; 22:1415–1423)

ISSN:0090-3493    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo assess the infection potential of not routinely changing invasive monitoring kits and associated plasticware.DesignA prospective, observational study of microbiological contamination of a cohort of pressure monitoring infusion systems.SettingAdult intensive care units in a university tertiary care center.PatientsPatients who had invasively monitored arterial, central venous, or pulmonary artery catheters in place for ≥96 hrs without a change to the system were entered into the study.InterventionsFluid samples were obtained from the proximal stopcock of the monitoring kits every 24 hrs, beginning with a sample at 72 hrs and continuing until either the plasticware or catheter was changed or discontinued. Fluid samples were placed in tryptic soy broth and spread on blood agar plates within 24 hrs.Measurements and Main ResultsOf 451 intervals in which the system remained unviolated for ≥96 hrs except for sampling, no positive cultures were found. Of the 333 monitoring kits/lines in the study, four cultures became positive within 48 hrs of a violation of the system (flush bag change). Positive cultures were obtained from two different patients, one patient having positive fluid cultures from arterial, central venous, and pulmonary arterial kits. This bacterial growth would not have been eliminated with routine system changes as it occurred within a 48-hr timeframe.ConclusionsInvasive hemodynamic pressure monitoring systems including tubing and plasticware need not be changed routinely as these changes may cause a higher incidence of contamination due to increased violations of the systems. (Crit Care Med 1994; 22:1424–1430)

ISSN:0090-3493    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo evaluate airway pressure release ventilation as a partial ventilatory support mode by comparing a demand-flow airway pressure release ventilation system with synchronized intermittent mandatory ventilation and pressure support ventilation.DesignProspective, nonrandomized, crossover trial.SettingMedical intensive care unit in a university medical center.PatientsSixteen consecutive patients without chronic obstructive pulmonary disease with mechanical ventilatory support of 25% to 75% of total minute ventilation on synchronized intermittent mandatory ventilation, or 25% to 75% of maximal pressure support level on pressure support ventilation.InterventionsEach mode of mechanical ventilation was supplied to patients with comparable levels of partial support for 30 mins.Measurements and Main ResultsAmong three different modes, demand-flow airway pressure release ventilation achieved the lowest peak airway pressure (airway pressure release ventilation 9.1 ± 2.6 cm H2O; pressure support ventilation 18.4 ± 4.6 cm H2O; synchronized intermittent mandatory ventilation 34.8 ± 7.7 cm H2O;p< .001). Hemodynamic status and oxygenation status were similar among these three modes. Five (31%) of the 16 patients felt that demandflow airway pressure release ventilation was a less comfortable mode than synchronized intermittent mandatory ventilation or pressure support ventilation. This finding had no clear correlation with their duration of airway pressure release, preset machine deflation rate, or inspiratory/expiratory ratio of machine breath. Gross asynchrony of effort and ventilator cycling was noticed in two (13%) patients while they were receiving demand-flow airway pressure release ventilation.ConclusionsWe conclude that for patients who do not have chronic obstructive pulmonary disease, demand-flow airway pressure release ventilation can provide effective partial ventilatory support with lower peak airway pressure when compared with pressure support ventilation and synchronized intermittent mandatory ventilation. However, this airway pressure release ventilation system may be less comfortable than the other two modes, and asynchrony may occur in some patients. (Crit Care Med 1994; 22:1431–1437)

ISSN:0090-3493    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveBacterial translocation from the gut has been invoked as a common inciting event for postinjury multiple organ failure. We previously showed that gut ischemia/reperfusion induces remote organ injury. The purpose of this study was to ascertain if endotoxin has a pivotal mechanistic role in this process.DesignProspective, randomized study.SettingAnimal laboratory.SubjectsSprague-Dawley rats weighing 300 to 350 g.InterventionsAnesthetized animals underwent 45 mins of superior mesenteric artery occlusion and 2 hrs of reperfusion; sham laparotomy served as controls. Endotoxin was eliminated with the murine immunoglobulin (Ig) M antibody E5, 3 mg/kg iv before the study.Measurements and Main ResultsPlasma endotoxin was measured by the limulus amebocyte lysate assay. At 2 hrs of reperfusion, circulating neutrophil priming was determined by the difference in superoxide generation with and without the activating stimulus, N-formyl-Met-Leu-Phe. Neutrophil sequestration in the lung was quantitated by myeloperoxidase activity, and by lung endothelial permeability by125I albumin lung/blood ratio. Endotoxin concentrations were not significantly (significance determined asp< .05) different between the gut ischemia/reperfusion and laparotomy groups (n = ≥5) during ischemia or reperfusion. Circulating neutrophil priming, neutrophil accumulation in the lung, and lung injury were provoked by gut ischemia/reperfusion, but not altered by endotoxin elimination.ConclusionGut ischemia/reperfusion primes circulating neutrophils and produces lung injury by a mechanism independent of endotoxin. (Crit Care Med 1994; 22:1438–1444)

ISSN:0090-3493    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectivesTo test whether perfluorocarbon-associated gas exchange (gas ventilation of the perfluorocarbon-liquid filled lung) could support oxygenation better than conventional positive pressure breathing in a piglet model of gastric aspiration-induced adult respiratory distress syndrome (ARDS).DesignProspective, randomized, blinded, controlled study.SettingA critical care research laboratory in a university medical school.SubjectsFourteen healthy piglets.InterventionsUnder α-chloralose anesthesia and metocurine iodide neuromuscular blockade, 14 piglets underwent tracheostomy; central venous, systemic and pulmonary arterial catheterizations; and volume-regulated continuous positive-pressure breathing. Homogenized gastric aspirate (1 mL/kg) titrated to pH of 1.0 was instilled into the tracheostomy tube of each subject at 0 min to induce ARDS. Hemodynamics, lung mechanics, and gas exchange were evaluated every 30 mins for 6 hrs. Seven piglets were treated at 60 mins by tracheal instillation of perflubron, a volume selected to approximate normal functional residual capacity, and were supported by perfluorocarbon-associated gas exchange without modifying ventilatory settings. Perflubron was added to the trachea every hour to replace evaporative losses.Measurements and Main ResultsThere was a significant difference in oxygenation over time when tested by repeated-measures analysis of variance (F test = 8.78,p< .01). On further analysis, the differences were not significant from baseline to 2.5 hrs but became increasingly significant from 2.5 to 6 hrs after injury (p< .05) in the inflammatory phase of gastric aspiration-induced ARDS. Histologic evidence for ARDS in the treated group 6 hrs after injury was lacking.ConclusionsIn the piglet model, perfluorocarbon-associated gas exchange with perflubron facilitates oxygenation in the acute phase of gastric aspiration-induced inflammatory ARDS when compared with conventional positive-pressure breathing. Histologic and physiologic data suggest that perfluorocarbon-associated gas exchange with perflubron might prevent ARDS if instituted after aspiration in the time window before the acute inflammatory process is manifest. (Crit Care Med 1994; 22:1445–1452)

ISSN:0090-3493    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectivesTo test the hypothesis that, in newborn piglets, the presence of a tension pneumothorax modifies the cardiovascular responses to hypoxia/hypercarbia.DesignProspective laboratory study.SettingPerinatal cardiovascular research laboratory at a university school of medicine.SubjectsSeven newborn piglets.InterventionsWe sequentially exposed the piglets to a baseline (control I) measure, hypoxia/hypercarbia, tension pneumothorax with normoxia/normocarbia, and tension pneumothorax with hypoxia/hypercarbia added.Measurements and Main ResultsBrain and systemic blood pressures and blood flow (radionuclide-microspheres) were measured. Hypoxia/hypercarbia resulted in increased brain perfusion (207 ± 61% of control, mean ± SEM,p< .05) and heart perfusion (176 ± 58% of control,p< .05) and decreased gastrointestinal perfusion (-37 ± 9% of control,p< .05). Tension pneumothorax with normoxia/normocarbia reduced the cardiac output (-70 ± 8% of control,p< .05), which was redistributed toward the brain (p< .05) at the expense of the gastrointestinal tract (p< .05). Although this redistribution in cardiac output persisted during tension pneumothorax with hypoxia/hypercarbia added, sustained reductions in cardiac output (-57 ± 11%, of control,p< .01) were associated with smaller increases in perfusion to brain (55 ± 54 vs. 207 ± 61% of control, tension pneumothorax with hypoxia/hypercarbia added, and hypoxia/hypercarbia time periods, respectively,p< .05) and heart (65 ± 49 vs. 176 ± 58% of control, tension pneumothorax with hypoxia/hypercarbia added, and hypoxia/hypercarbia time periods, respectively,p< .05) and larger decreases in blood flow to gastrointestinal tract, pancreas, and kidneys (p< .05) than with hypoxia/hypercarbia alone.ConclusionsTension pneumothorax-induced reductions in cardiac output limit the hypoxia/hypercarbia-mediated increases in perfusion to brain and heart and accentuate the hypoxia/hypercarbia-related decreases in perfusion to kidneys and splanchnic organs. (Crit Care Med 1994; 22:1453–1460)

ISSN:0090-3493    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectivesVascular beds vary in their responses to atrial natriuretic peptide and sodium nitroprusside. Both of these agents dilate blood vessels by increasing intracellular guanosine 3',5'-cyclic monophosphate (cyclic-GMP) but activate different enzymes in the vascular smooth muscle cell. We aimed to determine if the response of intracellular cyclic-GMP to atrial natriuretic peptide and sodium nitroprusside varies in smooth muscle cells cultured from different vascular beds.DesignProspective, repeated measures analysis of concentration-response curves.SettingAnesthesia research laboratory of an academic medical center.SubjectsGuinea pigs: Cultured guinea pig smooth muscle cells were obtained from three different blood vessels.InterventionsNone.Measurements and Main ResultsIntracellular cyclic-GMP was measured by radioimmunoassay and concentration-response curves of cyclic-GMP to atrial natriuretic peptide and sodium nitroprusside were determined.Cells from the thoracic aorta were the most responsive to atrial natriuretic peptide. Atrial natriuretic peptide (1 μM) increased cyclic-GMP concentrations to 72 ± 5 pmol/mg (20-fold increase) with a 50% effective concentration of 3 nM. The concentration-response curve in epicardial coronary smooth muscle cells was to the right with an 50% effective concentration for atrial natriuretic peptide of 20 nM and a maximum response of a ten-fold increase in cyclic-GMP. Coronary resistance vessel cells were unresponsive to atrial natriuretic peptide. In response to sodium nitroprusside, the concentration-response curve in coronary resistance vessel cells was significantly to the left of either thoracic aorta cells or the epicardial coronary cells. The 50% effective concentration for sodium nitroprusside in coronary resistance vessel smooth muscle cells was ∼1 μM, while in both thoracic aortic cells and epicardial coronary cells, the 50% effective concentration was ten times higher. Coronary resistance cells were the most responsive with a 62-fold increase in cyclic-GMP in response to 1 mM of sodium nitroprusside. The maximum response in thoracic aorta cells and epicardial cells was 20− and 30-fold, respectively.ConclusionsSmooth muscle cells respond differently to vasodilators. The response of these cultured cells mimics the response of the intact vascular bed from which they were obtained. These findings suggest that phenotypic properties of smooth muscle cells within a blood vessel contribute to the responsiveness of the vessel. (Crit Care Med 1994; 22:1461–1464)

ISSN:0090-3493    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo evaluate the occurrence of global cerebral ischemia in acute brain trauma with acute anemia by combined measurements of cerebral hemodynamics, oxygenation, and lactate production.DesignProspective, intervention study.SettingNeuroscience intensive care unit of a university hospital.PatientsAdults (n = 22) with severe acute brain trauma (Glasgow Coma Scores ranging from 4 to 8), undergoing frequent serial measurements of total hemoglobin content, jugular oxyhemoglobin saturation, arteriojugular oxygen content difference, arteriojugular lactate concentration difference, lactate-oxygen index, and cerebral blood flow, along with other routine procedures.Measurements and Main ResultsAcute anemia (disclosed by a total hemoglobin content of <11 g/dL in at least three measurements) was found in 19 (86%) of 22 patients. In 211 serial multivariate physiologic observations, only one (0.4%) disclosed abnormally negative arteriojugular lactate difference consistent with global cerebral ischemia. However, in 18 (8.5%) studies in seven (31.8%) patients, acute anemia resulted in markedly decreased values of arteriojugular oxygen content difference. The latter, in turn, yielded abnormally high values of lactate-oxygen index despite normal cerebral lactate production (arteriojugular lactate difference) and oxygenation (jugular oxyhemoglobin saturation).ConclusionsIn acute brain injury with acute anemia, global cerebral ischemia is a rare finding. However, false cerebral ischemia may be frequently found, if assessed by the lactate-oxygen index, because the denominator of the index (the arteriojugular oxygen content difference) frequently decreases as a function of decreasing hemoglobin, thus yielding false calculated ischemic high values for lactate-oxygen index despite normal cerebral oxygenation and lactate production. (Crit Care Med 1994; 22:1465–1470)

ISSN:0090-3493    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo investigate the efficacy of early, routine use of neuromuscular blocking agents for intracranial pressure management in patients with severe head injury.DesignRetrospective review of data from the Traumatic Coma Data Bank. The Traumatic Coma Data Bank was a collaborative project of the National Institute of Neurological Disorders and Stroke that involved four Level I trauma centers. The Traumatic Coma Data Bank prospectively collected data on 1,030 severe head-injured patients (Glasgow Coma Score of ≥8) between 1984 and 1987.SettingFour Level I trauma centers coordinated by the National Institute of Neurological Disorders and Stroke.PatientsA total of 514 Traumatic Coma Data Bank patients who met study inclusion criteria were divided into two groups: group 1 consisted of 239 patients who were pharmacologically paralyzed starting within the first intensive care unit (ICU) shift or ≤6 hrs into the second shift and lasting for at least 12 hrs. Group 2 contained the remaining 275 patients who did not fulfill these criteria.Measurements and Main ResultsWe analyzed the acute care course of these patients from the time of injury through admission, resuscitation, and ICU stay, as well as their rehabilitation follow-up results for ≤1 yr. These two groups did not differ significantly regarding admission intracranial computed tomography diagnosis, admission Glasgow motor score, percentage of monitored time that intracranial pressure was ≥20 mm Hg, or frequency of initial intracranial pressure ≥20 mm Hg. In group 2, more patients were aged >40 yrs (24% vs. 15% in group 1) or had admission hypotension (33% in group 2 vs. 25% in group 1). Multivariate regression analysis showed that ICU stay was significantly longer in group 1 (mean 7.76 days) than group 2 (mean 4.84 days;p< .001). The occurrence of pneumonia was significantly higher in group 1 (29% vs. 15%,p< .001). There was a tendency toward a higher occurrence of sepsis in group 1, but this difference did not reach statistical significance (11% vs. 7%,p= .08). The final Glasgow Outcome Scale scores for the two groups were not significantly different in those survivors with good and moderate outcomes. Although there were more deaths in group 2 (39% vs. 24%,p< .001), there were more vegetative or severely disabled survivors in group 1 (8% vs. 4% and 21% vs. 13%, respectively).ConclusionsOur findings suggest that early, routine, long-term use of neuromuscular blocking agents in patients with severe head injuries to manage intracranial pressure does not improve overall outcome and may actually be detrimental because of the prolongation of their ICU stay and the increased frequency of extracranial complications associated with pharmacologic paralysis. We suggest that routine early management of the head-injured patient in the ICU should be accomplished using sedation alone and that neuromuscular blockade should be generally reserved for patients with intracranial hypertension who require escalation of treatment intensity. (Crit Care Med 1994; 22:1471–1476)

ISSN:0090-3493    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo assess the performance of pediatric intensive care by an international standard.DesignProspective, cohort study.SettingNine-bed multidisciplinary pediatric intensive care unit (ICU) within a 174-bed, tertiary care children's hospital.PatientsConsecutive, unselected patients (n = 612) during a 16-month period.InterventionsNone.Measurements and Main ResultsCollected data included age, major diagnostic category, primary clinical specialty, severity of illness (daily Pediatric Risk of Mortality [PRISM] score), administration of ICU-dependent therapy (daily), and vital status at discharge. The PRISM score allowed the calculation of overall and daily mortality risk. After testing the applicability of the predictive model, effectiveness was determined by comparing severity of illness-based predicted mortality rate with vital status at discharge. Efficiency was defined by two criteria: a) the administration of at least one ICU-dependent therapy; or b) a mortality risk of >1%. Five-hundred ninety-three patients were included (19 survivors were excluded because of incomplete data). Mean age was 55.0 months (median 24). Mean length of stay was 4.4 days (median 2). Overall ICU mortality rate was 8.4%. The overall performance of the PRISM score-based predictive model was found to be good (goodness-of-fit test χ2[5] = 5.49;p= .35; area under receiver operating characteristic curve 0.92). Subgroup analysis showed that the best model performance was in nonoperative patients. Decreased performance was found in operative patients. In cardiovascular patients, the mortality rate was higher. In other surgical patients, the mortality rate was lower than expected. Of 593 patients, 489 (82.5%) admissions were efficient, as were 2,393 (76.5%) of 3,130 patient days in the ICU. The ranking of daily efficiency according to clinical specialty was as follows: postoperative cardiovascular surgical patients (86.3%); nonsurgical patients (76.6%); and other postoperative patients (49.6%).ConclusionsIn our setting, effectiveness and efficiency of pediatric intensive care appeared to be validly determined using explicit criteria (mortality risk, administration of ICU-dependent therapy). Overall effectiveness met the standard set forth in an American study; validity in stratified analysis of diagnostic subgroups remains to be further established. Efficiency showed marked, specialty-related differences. The low efficiency in other (noncardiovascular) surgical patients was probably caused by the recovery function of the ICU. A more general application of these criteria might be considered in modifying admission and discharge policy, as well as in quality control. (Crit Care Med 1994; 22:1477–1484)

ISSN:0090-3493    

出版商:OVID    

年代:1994

数据来源: OVID