摘要:

ObjectiveTo determine whether dexamethasone prevents postextubation airway obstruction in young children.DesignProspective, randomized, double-blind, placebo-controlled study.SettingPediatric intensive care unit of a university teaching hospital.Patients48 hrs.InterventionsPatients were randomized to receive intravenous dexamethasone (0.5 mg/kg, maximum dose 10 mg) or saline, every 6 hrs for six doses, beginning 6 to 12 hrs before elective extubation.Measurements and Main ResultsDependent variables included the presence of stridor, Croup Score, and pulsus paradoxus at 10 mins, 6, 12, and 24 hrs after extubation; need for aerosolized racemic epinephrine and reintubation. The dexamethasone and placebo groups were similar in age (median 3 months [range 1 to 57] vs. 4 months [range 1 to 59], p = .6), frequency of underlying airway anomalies (3/33 vs. 3/33, p = 1.0), and duration of mechanical ventilation (median 3.3 days [range 2.1 to 39] vs. 3.5 days [range 2.1 to 15], p = .7). The dexamethasone group had a lower frequency of stridor, Croup Score, and pulsus paradoxus measurement at 10 mins and at 6 and 12 hrs after extubation. Fewer dexamethasone-treated patients required epinephrine aerosol (4/31 vs. 22/32, p < .0001) and reintubation (0/31 vs. 7/32, p < .01). Three patients exited the study early--one patient in the dexamethasone group had occult gastrointestinal hemorrhage and one patient in each group had hypertension.ConclusionPretreatment with dexamethasone decreases the frequency of postextubation airway obstruction in children.(Crit Care Med 1996; 24:1666-1669)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo determine if histamine release occurs in clinical sepsis.DesignProspective, controlled, clinical study.SettingInterdisciplinary intensive care unit and trauma ward.PatientsSepsis was confirmed in 20 patients (test group) by the criteria of the Veterans Administration Systemic Sepsis Cooperative Study Group (1987) and was verified by positive blood culture. In addition, patients were scored by the Elebute and Stoner Sepsis Score (1983), as modified by Dionigi et al (1985). A concomitant control group consisted of 20 postoperative patients with non-life-threatening trauma to the extremities and without signs of local or systemic infection.InterventionsObservational study. Blood samples were collected for determination of plasma histamine concentrations in both groups at the time of study entry and on five succeeding days.Measurements and Main Results1 ng/mL) died.ConclusionIncreased histamine concentrations were shown to be causally associated (contributory determinant) with sepsis.(Crit Care Med 1996; 24:1670-1677)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo compare the efficacy of venovenous to venoarterial bypass in an unselected cohort of infants with refractory cardiorespiratory failure.DesignRetrospective cohort analysis.SettingTwo tertiary hospitals capable of providing extracorporeal life support for neonates with acute respiratory failure.PatientsAll San Diego Regional Extracorporeal Membrane Oxygenation (ECMO) Program patients treated after the adoption of a policy which eliminated traditional restrictions to venovenous support.InterventionsVenoarterial or venovenous extracorporeal life support.Measurements and Main ResultsFifty-four infants were treated with venovenous bypass; 30 were treated with venoarterial bypass due to unsuccessful placement of the double lumen venovenous catheter or inability to exclude congenital heart disease before cannulation. No patient required conversion from venovenous to venoarterial ECMO. There were no differences in birth weight, gestational age, diagnosis, or pre-ECMO condition in the two groups. Patients who met ECMO criteria early were more likely to be successfully cannulated with a double-lumen venovenous catheter. Severe hemodynamic compromise was present before cannulation in a comparable percentage of venovenous and venoarterial patients. During venovenous bypass, mean PaO2values were lower but remained in the normoxic range; PaCO2values, ventilatory settings, intravascular volume requirements, inotropic support, and mean duration of ECMO support were not different. The frequency rate of patient and mechanical complications were also comparable, except that the frequency of intravascular thrombosis was significantly lower in patients receiving venovenous ECMO. Survival, the frequency rate of chronic lung disease, and neurodevelopmental outcome were similar in the two groups.ConclusionsWe conclude that venovenous ECMO using a double-lumen venovenous catheter can provide results comparable with venoarterial bypass without the need for carotid artery ligation in an unselected population of neonatal ECMO candidates. In our experience, reported contraindications to venovenous ECMO did not prove to be valid.(Crit Care Med 1996; 24:1678-1683)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo evaluate the accuracy and reliability of noninvasive continuous finger blood pressure measurement in critically ill patients.DesignProspective data collection.SettingEmergency department in a 2,000-bed hospital.PatientsThirty-nine patients admitted to the emergency department requiring invasive arterial blood pressure monitoring were enrolled to the study protocol.InterventionsContinuous noninvasive blood pressure measurement was performed on the middle phalanx of the second and third finger, using a test instrument which provides continuous arterial waveform display with the use of a finger cuff. Invasive mean arterial blood pressure measurement was done by cannulation of the radial artery and direct transduction of the systemic arterial pressure waveform.Measurements and Main Results3 mins.Conclusions3 mins were noted. Concerning the considerable risk for arterial cannulation, our preliminary data demonstrate that the test instrument (PORTAPRES Registered Trademark, TNO Biomedical Instrumentation Research Unit; The Netherlands) is an advance in noninvasive monitoring of critically ill patients and may be useful in most emergency clinical settings.(Crit Care Med 1996; 24:1684-1689)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo compare a blind manual bedside method for placing feeding tubes into the small bowel vs. a sonographic bedside technique in critically ill patients.DesignProspective study with a random sample.SettingMultidisciplinary intensive care unit in a tertiary care university hospital.PatientsThirty-five adult patients. All patients were hemodynamically stable, mechanically ventilated, and required a nasoenteric tube placement for short-term enteral feeding due to impaired gastric emptying.InterventionsA well-known, blind, manual, bedside method for postpyloric tube placement was always attempted first in all cases. The technique was considered successful when a postpyloric location of the tip of the tube was achieved as shown by abdominal roentgenogram. However, if after 30 mins we failed to enter the small bowel, a radiologist attempted a sonographic bedside technique for postpyloric tube insertion. Finally, when the feeding tube was in place, before starting enteral nutrition, a nasogastric tube was inserted into the stomach.Measurements and Main ResultsThe blind manual method was successful in nine (25.7%) of the 35 patients and the final location of these feeding tubes was the proximal jejunum. The average time for placement of the feeding tubes with this manual technique was 13.9 +/- 7.4 mins (range 5 to 30). The sonographic technique was succesful in 22 (84.6%) of the remaining patients and the final location of the feeding tubes was three (11%) tubes in the second portion of the duodenum, eight (31%) tubes in the third portion of the duodenum, and 11 (42%) tubes in the proximal jejunum. The average time for placement with the sonographic technique was 18.3 +/- 8.2 mins (range 5 to 35). The pyloric outlet was sonographically akinetic or severely hypokinetic in 13 patients, and in four of them, we were unable to achieve postpyloric tube placement. In these four patients, the tubes were subsequently placed by endoscopy.ConclusionsThe sonographic bedside technique for placing feeding tubes into the small bowel in critically ill patients has a success rate of 84.6% (confidence interval 71% to 98%) after the failure of the blind bedside manual method, proving that the former is significantly more successful. This sonographic technique facilitates the insertion of the tubes in patients who cannot be moved and in those patients with severe impairment of the peristaltic activity of the stomach.(Crit Care Med 1996; 24:1690-1694)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo determine whether high-dose epinephrine administration during cardiopulmonary resuscitation (CPR) in a swine pediatric asphyxial cardiac arrest model improves outcome (i.e., resuscitation rate, survival rate, and neurologic function) compared with standard-dose epinephrine.DesignA randomized, blinded study.SettingA large animal cardiovascular laboratory at a university.SubjectsThirty domestic piglets (3 to 4 months of age) were randomized to receive standard-dose epinephrine (0.02 mg/kg) or high-dose epinephrine (0.2 mg/kg) during CPR after 10 mins of cardiac standstill with loss of aortic pulsation after endotracheal tube clamping.InterventionsTwo minutes of CPR were provided, followed by advanced pediatric life support. Successfully resuscitated animals were supported in an intensive care unit (ICU) setting for 2 hrs and then observed for 24 hrs.Measurements and Main ResultsElectrocardiogram, thoracic aortic blood pressure, and right atrial blood pressure were monitored continuously until the intensive care period ended. Survival rate and neurologic outcome were determined.Return of spontaneous circulation was obtained in 13 of 15 high-dose epinephrine piglets vs. ten of 15 standard-dose epinephrine piglets (p < .20). Four of 13 high-dose piglets died in the ICU period after initial resuscitation vs. 0 of ten standard-dose piglets (p <or=to .05). Nine high-dose piglets survived 2 hrs vs. ten standard-dose piglets. Three piglets in each group survived for 24 hrs, but all were severely neurologically impaired.240 beats/min) was more frequently noted in the high-dose group than in the standard-dose group (p < .05). All four high-dose piglets that died in the ICU period experienced ventricular fibrillation within 10 mins of return of spontaneous circulation.ConclusionsHigh-dose epinephrine did not improve 2-hr survival rate, 24-hr survival rate, or neurologic outcome. High-dose epinephrine resulted in severe tachycardia and hypertension immediately after resuscitation and in a higher mortality rate immediately after resuscitation.(Crit Care Med 1996; 24:1695-1700)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo examine the utility of single breath CO2analysis as a noninvasive measure of cardiac output.SettingAn animal laboratory in a university-affiliated medical center.DesignA prospective, animal cohort study comparing 21 parameters derived from single breath CO2analysis with cardiac output determined by an ultrasonic flow probe.SubjectsSix healthy adult sheep.MethodsThe single breath CO2analysis station consists of a mainstream capnometer, a variable orifice pneumotachometer, a signal processor, and computer software with capability for both on- and off-line data analysis. Twenty-one derived components of the CO2expirogram were evaluated as predictors of cardiac output. Cardiac output was manipulated by successive injections of a hydraulic constrictor placed around the inferior vena cava.Measurements and Main ResultsThirty-four measurements of cardiac output were available for comparison with derived variables from the CO2expirogam. Stepwise linear regression identified two variables that were most predictive of cardiac output: a) the angle between the slope lines for phases II and III of the CO2expirogram divided by the volume of CO2per breath (angle/mL CO2); and b) the slope of phase II. The multivariate equation was highly statistically significant and explained 94% of the variance (adjusted r2= .94, p < .0001). The bias and precision of the calculated cardiac output were .00 and .23, respectively. The mean percent difference for the cardiac output estimate derived from the single breath CO2analysis station was 0.36%.ConclusionsOur data indicate that analysis of the CO2expirogram can yield accurate information about the cardiovascular system. Specifically, two variables derived from a plot of expired CO2concentration vs. expired volume predict changes in cardiac output in healthy adult sheep with an adjusted coefficient of determination of .94. Prospective application of this technology in the setting of lung injury and rapidly changing physiology will be essential in determining the clinical usefulness of the technique.(Crit Care Med 1996; 24:1701-1705)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo determine the effects of stimulation of vascular dopaminergic receptor subtype 1 (dopamine-1) receptors in the renal and mesenteric vascular beds of a neonatal model.DesignProspective, unblinded, dose-response evaluation in an awake animal.SettingUniversity research laboratory.SubjectsThirty newborn piglets, obtained and instrumented at 1 to 3 days of age and studied 48 hrs later.InterventionsAnimals were chronically instrumented with transit time ultrasound flow probes around the left renal and superior mesenteric arteries. They were then intravenously infused with either dopamine (2 to 32 micro gram/kg/min) or fenoldopam (1 to 100 micro gram/kg/min), which is a selective agonist of the dopamine-1 receptor.Measurements and Main ResultsBlood pressure was only significantly increased by the highest infusion rate of dopamine (32 micro gram/kg/min), from a mean of 78 mm Hg at baseline to 87 mm Hg. Mesenteric and renal vascular resistances were unchanged by dopamine at any dose. Dopamine at 32 micro gram/kg/min decreased renal blood flow by 16.6 +/- 19.6 (SD) % and increased renal vascular resistance by 39.6 +/- 41.1% (p < .05). Mesenteric blood flow increased by 15% at 32 micro gram/kg/min (p < .05) but mesenteric vascular resistance was not affected by dopamine. Fenoldopam reduced blood pressure at infusion rates of 5, 10, and 100 micro gram/kg/min. Fenoldopam had no effect on renal vascular resistance at any dose. Fenoldopam reduced mesenteric vascular resistance at 5 micro gram/kg/min and at all higher doses.ConclusionsThese data demonstrate the absence of dopaminergic receptor-mediated vasodilation in the porcine neonatal renal vascular bed. In the mesenteric artery, dopamine-1 receptor-mediated vasodilation may be obtained. Dopamine itself, probably because of stimulation of other receptors, causes renal artery vasoconstriction and does not increase superior mesenteric artery blood flow.(Crit Care Med 1996; 24:1706-1712)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo study the effect of tris buffer on free cytosolic calcium in vitro.DesignOpen, randomized, control trial of dispersed rat myocardial cells.SettingExperimental laboratory in a large university hospital.SubjectsDispersed myocardial cells from Sprague-Dawley rats.InterventionsThe influences of pure trometamol (tris) and a tris buffer mixture, as well as conventional sodium bicarbonate on free cytosolic calcium in suspended rat myocardial cells were studied with the fluorescent intracellular probe fura-2.Measurements and Main ResultsAddition of pure trometamol (tris) resulted in a significant increase of free cytosolic calcium in myocardial cells suspended in a buffer containing 1.25 mM of ionized calcium. The actions of trometamol display a dose-dependency in relation to the concentration of external ionized calcium since the ionized calcium response was reduced in a buffer with 0.5 mM of extracellular ionized calcium. Furthermore, removal of external lonized calcium totally prevented trometamol induced increases of ionized calcium, indicating that this increase is dependent on transmembrane ionized calcium fluxes. When tris buffer mixture was investigated in 1.25 mM of calcium, as well as 0.5 mM of external ionized calcium, a decrease of ionized calcium was noted initially, followed by an increase during the observation period. Addition of sodium bicarbonate to the two experimental settings resulted in a more prominent initial decrease of ionized calcium, followed by a slower increase which did not reach the initial values during the 20-min observation period.Extracellular pH was also included as a variable.When the cells were suspended in a buffer containing 1.25 mM of ionized calcium with a pH of 6.80 instead of 7.40 (as above), addition of pure trometamol also resulted in an increase of ionized calcium; however, after 20 mins this increase was smaller as compared with the results above. When tris buffer mixture as well as sodium bicarbonate was added, initial decreases of ionized calcium were recorded, followed by smaller increases during the observation period, compared with the increase in buffers with a pH of 7.40.ConclusionsPure trometamol (tris) induces an increase in free cytosolic calcium in suspended myocardial cells.(Crit Care Med 1996; 24:1713-1718)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectivesPatients suffering out-of-hospital cardiac arrest have various degrees of acidemia when cardiopulmonary resuscitation is initiated. Myocardial hypercarbia, rather than decreases in myocardial pH, may determine cardiac resuscitability. Accordingly, we questioned whether different degrees of acidemia accompanying cardiac arrest affect cardiac resuscitability. We evaluated the effect of different degrees of extramyocardial acidosis on cardiac performance and resuscitability after ventricular fibrillation using isolated, perfused, rat hearts.DesignProspective, randomized, controlled study.SettingExperimental animal laboratory in a university hospital.SubjectsThirty-one male, Sprague-Dawley rats.InterventionsRat hearts were perfused with N-[2-hydroxyethyl]piperazine-N-[2-ethanesulfonic acid] (HEPES) buffered solution (sodium chloride 145 mM, potassium chloride 4 mM, sodium dihydrogen phosphate dihydrate 1.25 mM, magnesium chloride 1.5 mM, calcium chloride 2 mM, HEPES 6 mM, glucose 10 mM), which was bubbled with 100% oxygen and adjusted to a pH of 7.4. The perfusion pressure was held constant at 60 mm Hg. After 60 mins of stabilization, the control perfusion solution was switched to one of the solutions titrated to pH 6.2, 6.5, 6.8, 7.1, or 7.4, using 1 N of sodium hydroxide. Hearts were allocated randomly to each group. After 15 mins of perfusion, the perfusion was discontinued, and artificial ventricular fibrillation was induced by electrical stimulation for 5 mins. The hearts were then perfused again in one of the same acidotic solutions for 30 mins.Measurements and Main Results35 mm Hg as "resuscitated," resuscitability was impaired at a pH of <7.1. No hearts recovered after perfusion below a pH of 6.5.ConclusionsExtramyocardial acidosis below pH 7.1 decreased cardiac performance and resuscitability after ventricular fibrillation. This result indicates that progressive acidemia during cardiac arrest is one of the important determinants of cardiac resuscitability.(Crit Care Med 1996; 24:1719-1723)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID