摘要:

Objective:To determine whether the use of nitric oxide (NO)-releasing polymers coated onto the inner surface of extracorporeal circuits can reduce platelet consumption and activation in the absence of systemic heparinization using a rabbit model of venovenous extracorporeal circulation.Design:Prospective, controlled trialSetting:Research laboratory at an academic medical institution.Subjects:New Zealand White RabbitsInterventions:Anesthetized, tracheotomized, and ventilated New Zealand White rabbits were injected with freshly prepared,111In(oxine)3labeled single donor platelets through the external jugular vein. After baseline measurements, these animals were placed on venovenous extracorporeal circulation through a 1-m control circuit or NO test circuit for 4 hrs at a blood flow rate of 109-118 mL/min via roller pump. Four groups were studied: systemically heparinized control circuits, systemically heparinized NO test circuits, nonheparinized control circuits, and nonheparinized NO test circuits. Platelet counts, fibrinogen levels, and plasma free indium levels were measured hourly. Circuits were rinsed and retained for gamma counting after the 4-hr run or when the circuit clotted. Four animals, one from each group, did not receive radiolabeled platelets so that the circuits could be preserved for scanning electron microscopic examination after the 4-hr study.Measurements and Main Results:Platelet consumption was significantly reduced in both the heparinized and nonheparinized NO test groups when compared with the controls (p< .0001 andp< .0004, respectively). Platelet adhesion to the extracorporeal circuits was significantly reduced in the nonheparinized test circuits when compared with the controls (p< .05). Scanning electron microscopic examination of the circuits revealed that in the absence of heparin and in the presence of a NO-releasing surface, platelets retained their spherical nonactivated shape.Conclusions:The incorporation of NO into the surface of extracorporeal circuits reduces platelet consumption and eliminates the need for systemic heparinization in a rabbit model of extracorporeal circulation.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:The renal effects of dopamine in critically ill patients remain controversial. Low-dose dobutamine has been reported to improve renal function. We compared the effects of various doses of dopamine and dobutamine on renal function in critically ill patients.Design:Prospective, single-blind, randomized study.Setting:University hospital, 19-bed multidisciplinary intensive care unit.Patients:Twelve hemodynamically stable patients with mild nonoliguric renal impairment.Interventions:Each patient randomly received four different doses of dopamine and dobutamine (placebo, 3, 7, and 12 μg/kg/min). Each infusion lasted for 4 hrs. Cardiac output and systemic hemodynamic variables were measured using a pulmonary arterial catheter at the beginning (HO) and the end (H4) of each infusion. The bladder was emptied at HO and H4 to determine urine volume and to collect samples.Measurements and Main Results:The cardiac index increased significantly with both dopamine and dobutamine (p< .001). Mean arterial pressure (MAP) increased, with the maximum effect of 20% seen with 12-μg/kg/min dopamine infusion (p< .01). No change in MAP was seen with dobutamine. Dobutamine infusions did not change any renal variables. Conversely, all dopamine infusions significantly increased diuresis, creatinine clearance, and the fractional excretion of sodium (p< .01). Creatinine clearance increased from 61 ± 16.9 (SD) mL/min to a maximum of 85.7 ± 30 mL/min at the 7-μg/kg/min dose; fractional excretion of sodium increased from 0.26% ± 0.28% to a maximum of 0.62% ± 0.51% at the 12-μg/kg/min dose (p< .01). During dopamine infusions, there was a significant relationship between MAP and creatinine clearance (p= .018).Conclusions:At all doses studied, 4-hr infusions of dopamine significantly increased creatinine clearance, diuresis, and the fractional excretion of sodium in stable critically ill patients. Conversely, dobutamine did not modify these variables. Although the level of MAP might partially contribute to the improvement in renal variables, it is more likely that the activation of renal dopamine receptors played a prominent role.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To determine interleukin (IL)-8 concentrations in ventricular cerebrospinal fluid from children with severe traumatic brain injury (TBI).Design:Prospective study.Setting:University children's hospital.Patients:Twenty-seven children hospitalized with severe TBI (Glasgow Coma Scale score ≤8), seven children with cerebrospinal fluid culture-positive bacterial meningitis, and twenty-four age-equivalent controls.Interventions:Placement of an intraventricular catheter and continuous drainage of cerebrospinal fluid.Measurements and Main Results:Median [range] cerebrospinal fluid IL-8 concentration in children with TBI (0-12 hrs) (4,452.5 [0-20,000] pg/mL) was markedly greater than that in controls (14.5 [0-250]) (p< .0001) and equivalent to concentrations in children with meningitis (5,300 [1,510-22,000] pg/mL) (p= .33). Cerebrospinal fluid IL-8 remained increased in children with severe TBI for up to 108 hrs after injury. Univariate logistic regression analysis demonstrated an association between cerebrospinal fluid IL-8 and child abuse (p= .07) and mortality (p= .01). Multivariate analysis demonstrated a strong, independent association between cerebrospinal fluid IL-8 and mortality (p= .01).Conclusions:The data are consistent with an acute inflammatory component of TBI in children and suggest an association between cerebrospinal fluid IL-8 and outcome after TBI. IL-8 may represent a potential target for anti-inflammatory therapy.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To determine the risk factors related to the presence of postsurgical nosocomial pneumonia (NP) in patients who had undergone cardiac surgery.Design:A case-control study.Setting:Postcardiac surgical intensive care unit at a university center.Patients:A total of 45 patients with NP and 90 control patients collected during a 4-yr period.Interventions:Pre-, intra-, and postoperative factors were collected and compared between two groups of patients (cases vs. controls) to determine their influence on the development of NP. The diagnosis of NP was always microbiologically confirmed as pulmonary specimen brush culture of ≥103colony-forming units/mL or positive blood culture/pleural fluid culture by the growth of identical microorganisms isolated at the lung. For each patient diagnosed with NP, we selected control cases at a ratio of 1:2.Measurements and Main Results:The incidence of NP was 6.5%. Multivariate analysis found a probable association of the following variables with a greater risk for the development of NP: reintubation (adjusted odds ratio [AOR], 62.5; 95% confidence interval [CI], 8.1-480;p= .01); nasogastric tube (AOR, 19.7; 95% CI, 3.5-109;p= .01), transfusion of ≥4 units of blood derivatives (AOR, 12.8; 95% CI, 2-82;p= .01) and empirical treatment with broad-spectrum antibiotics (AOR, 6.6; 95% CI, 1.2-36.8;p= .02). Culture results showed 13.3% of the NP to be of polymicrobial origin, whereas 77.3% of the microorganisms isolated were Gram-negative bacteria. The mortality (51 vs. 6.7%,p< .01) and the length of stay in the intensive care unit (25 ± 14.8 days vs. 5 ± 5 days,p< .01) were both greater in patients with NP.Conclusions:We conclude that the surgical risk factors, except the transfusion of blood derivatives, have little effect on the development of NP. Reintubation, nasogastric tubing, previous therapy with broad-spectrum antibiotics, and blood transfusion are factors most likely associated with NP acquisition.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To define the magnitude of spontaneous cardiac output variability over time in sedated medical intensive care unit patients attached to a continuous cardiac output monitor, and to determine whether high level positive end-expiratory pressure or inverse inspiratory-to-expiratory (I:E) ratio ventilation resulted in greater variability over time than low positive end-expiratory pressure with conventional I:E ratio ventilation.Design:Prospective study.Setting:Medical intensive care unit in a tertiary medical center.Patients:A total of 22 hemodynamically stable acute respiratory failure patients with a pulmonary artery catheter inserted for hemodynamic monitoringInterventions:After being sedated, patients were randomized alternately to receive pressure control ventilation first at setting A (high positive end-expiratory pressure [15 cm H2O] with conventional I:E ratio [1:2]) and then at setting B (low positive end-expiratory pressure [5 cm H2O] with inverse I:E ratio [2:1]), or vice versa, and then at setting C (low positive end-expiratory pressure [5 cm H2O] with conventional I:E ratio [1:2]). Each ventilation setting period lasted 1 hr.Measurements and Main Results:Cardiac output (CO) was measured continuously. The continuous CO value displayed was updated every 30-60 secs. The updated value reflected an average of the previous 3-6 mins. The coefficient of variation (CV) of CO for each setting in each patient was calculated to represent the spontaneous variability. The mean CO ± SD and CV of each setting was 5.7 ± 1.8 L/min and 4.4% for setting A, 5.6 ± 1.5 L/min and 4.6% for setting B, and 5.9 ± 1.7 L/min and 4.8% for setting C. Analysis of variance revealed no significant differences between the CVs of the three settings. The 95% confidence interval for the COs for each setting was approximately the mean CO ± 0.1 × mean CO measured.Conclusions:In critically ill sedated medical intensive care unit patients with stable hemodynamics, the spontaneous variability of cardiac output over time was not significant. High positive end-expiratory pressure (15 cm H2O) and inverse ratio ventilation (2:1) did not contribute to increased spontaneous variability of cardiac output.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:The aim of the study was to determine the prognosis in patients who needed norepinephrine treatment in our institution in relation to the degree of organ failure and the evolution of the disease process.Design:Retrospective case note analysis of outcome of those patients who needed norepinephrine according to our institutional regimen.Patients:A total of 100 consecutive patients admitted to our 31-bed medical-surgical intensive care unit (ICU) who were treated with norepinephrine for severe hypotension and evidence of end-organ hypoperfusion unresponsive to both fluid resuscitation and dopamine treatment at 20 μg/kg/min.Measurements:The degree of organ dysfunction at the time of starting norepinephrine treatment was assessed by the sequential organ failure assessment (SOFA) score. The time before starting norepinephrine treatment was defined as the time elapsed between ICU admission and that of starting norepinephrine administration. The patients were defined as survivors or nonsurvivors according to their ICU outcome.Results:There were relationships between mortality and the degree of organ dysfunction and mortality and the duration of ICU stay before starting norepinephrine treatment. The mortality rate was 100% in the 30 patients with a total SOFA score of >12 and a delay before starting norepinephrine treatment of >1 day. The mortality rate of the other patients was 63%. The lowest mortality was seen in patients with lower SOFA scores and early norepinephrine administration after admission.Conclusions:Both the time of starting norepinephrine treatment after admission to the ICU and the degree of organ dysfunction have an important bearing on subsequent outcome. Although norepinephrine may be a lifesaving catecholamine in some cases, its administration to patients who have already developed multiple organ failure during their stay in the ICU is associated with a poor outcome.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To compare procalcitonin (PCT) plasma levels of injured patients with the incidence and severity of systemic inflammatory response syndrome (SIRS), infection, and multiple organ dysfunction syndrome (MODS) and to assess the predictive value of PCT for these posttraumatic complications.Design:Retrospective study comparing patients with mechanical trauma in terms of severity of injury, development of infectious complications, and organ dysfunctions.Setting:Level I trauma center with emergency room, intensive care unit, and research laboratory.Patients:Four hundred five injured patients with an Injury Severity Score of ≥9 points were enrolled in this study from January 1994 to February 1996.Interventions:Blood samples were collected on the day of admission and on days 1, 3, 5, 7, 10, 14, and 21 thereafter.Measurements and Main Results:We determined PCT serum levels using a specific immunoluminometric assay. We retrospectively evaluated the occurrence of SIRS, sepsis, and MODS using patients' charts. Mechanical trauma led to increased PCT plasma levels dependent on the severity of injury, with peak values on days 1 and 3 (p< .05) and a continuous decrease within 21 days after trauma. Patients who developed SIRS demonstrated a significant (p< .05) increase of peak PCT plasma levels compared with patients without SIRS. The highest PCT plasma concentrations early after injury were observed in patients with sepsis (6.9 ± 2.5 ng/mL; day 1) or severe MODS (5.7 ± 2.2 ng/mL; day 1) with a sustained increase (p< .05) for 14 days compared with patients with an uneventful posttraumatic course (1.1 ± 0.2 ng/mL). Moreover, these increased PCT plasma levels during the first 3 days after trauma predicted (p< .0001; logistic regression analysis) severe SIRS, sepsis, and MODS.Conclusions:These data indicate that PCT represents a sensitive and predictive indicator of sepsis and severe MODS in injured patients. Routine analysis of PCT levels seems to aid early recognition of these posttraumatic complications. Thus, PCT may represent a useful marker to monitor the inflammatory status of injured patients at risk.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To investigate the treatment of nitric oxide (NO)-induced methemoglobinemia by methylene blue (MB), riboflavin, andN-acetylcysteine (NAC)in vitro.Design:Prospective, controlledin vitrostudy.Setting:Research laboratory in a university hospital.Participants:Five healthy volunteers.Interventions:Generation of 16% to 18% of methemoglobin in red blood cells by NO and subsequent addition of MB, riboflavin, or NAC. Simultaneous NO (32 ppm) and MB or riboflavin exposure of red blood cells. Induction of 14% to 18% of methemoglobin in red blood cells by NO, subsequent addition of MB or riboflavin, and further incubation with NO (80 ppm).Measurements and Main Results:After discontinuation of NO, mean half-life for methemoglobin was significantly reduced by MB from 356 mins (controls) to 5 mins (10 μM) in a dosedependent manner (p< .001). NAC did not alter the half-life for methemoglobin, and a reduction from 356 to 168 mins was seen for 120 μM riboflavin (p< .001). Methemoglobin formation after 3 hrs of NO exposure was 4.3% ± 0.7% in controls and 0.3% ± 0.1% with 10 μM MB (p< .001); 1 μM MB attenuated methemoglobin formation to 1.9% ± 0.1% (p< .01). With riboflavin (120 μM), methemoglobin was 2.2% ± 0.5% vs. 3.2% ± 0.6% in controls (p< .001). In the presence of high methemoglobin concentrations, further methemoglobin formation was inhibited by 1 and 10 μM MB (p< .001) and attenuated by 0.1 μM MB (p< .001) but not by riboflavin.Conclusions:In vitro,NO-induced methemoglobin formation is significantly decreased by medium (1 μM) and high (10 μM) concentrations of MB and partially by high riboflavin concentrations (120 μM). NAC and low concentrations of riboflavin do not alter methemoglobin formation.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To compare direct examination of bronchial aspirate and plugged telescopic catheter specimens (PTC) with infected cell counts in bronchoalveolar lavage (BAL) specimens for the diagnosis of nosocomial pneumonia.Design:Prospective study of critically ill patients.Setting:Intensive care unit in a university hospital.Patients:A total of 64 patients hospitalized for >48 hrs with suspected nosocomial pneumonia.Interventions:Fiberoptic bronchoscopy with bronchial aspirate and quantitative protected specimen brush, PTC, and BAL cultures. PTC and bronchial aspirate specimens were Gram-stained. BAL specimens for infected cell counts were examined as described previously in the literature.Measurements and Main Results:Nosocomial pneumonia was diagnosed by the medical staff based on all available clinical, radiologic, laboratory test, and microbiological data and on the course before and after appropriate therapy. A total of 71% of patients were ventilated, and 70.1% were receiving antibiotics. Nosocomial pneumonia was diagnosed in 54% of the cases. On direct examination, sensitivity (Se) and specificity (Sp) of bronchial aspirate specimens were Se, 82% and Sp, 60%; of BAL with 5% infected cells, Se, 56% and Sp, 100%; of BAL with 3% infected cells, Se, 74% and Sp, 96%; of PTC specimens, Se, 65% and Sp, 76%; and of PTC specimens plus BAL with 3% infected cells, Se, 83% and Sp, 78%. BAL with 3% infected cells was significantly better for predicting nosocomial pneumonia than direct examination of bronchial aspirate or PTC specimens (p= .0012). When the BAL showed 3% infected cells, neither direct examination of bronchial aspirate nor direct examination of PTC specimens was useful (p= .24 andp= .38, respectively). Combined use of direct examination of PTC specimens plus BAL with 3% infected cells markedly improved sensitivity. The total cost of each procedure was taken into account for the final evaluation.Conclusions:Our data suggest that BAL with 3% infected cells is currently the only test whose predictive value for nosocomial pneumonia is sufficiently high to be of use for guiding the initial choice of antimicrobial class while waiting for quantitative culture results.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:μ-Opioid receptor blockade during general anesthesia is a new treatment for detoxification of opioid addicted patients. We assessed catecholamine plasma concentrations, oxygen consumption, cardiovascular variables, and withdrawal symptoms after naloxone and tested the hypothesis that variables are influenced by the anesthetic administered during detoxification.Design:Prospective randomized clinical study.Setting:Intensive care unit of a university hospital and psychiatric ward.Patients:Twenty-five mono-opioid addicted patients with mild to moderate systemic disease (ASA II classification) in a methadone substitution program.Intervention:General anesthesia with either propofol (129 ± 7 μg·kg−1·min−1, mean ± SEM) or methohexital (74 ± 14 μg·kg−1·min−1), μ-opioid receptor blockade by naloxone in a stepwise fashion (increasing doses of 0.4 mg, 0.8 mg, 1.6 mg, 3.2 mg, and 6.4 mg at 15 min intervals followed by 0.8 mg·hr−1for 24 hrs) and naltrexone 50 mg·day−1orally for ≥4 wks. Clonidine was started 180 mins after the first naloxone dose and its infusion rate was individually adjusted to mitigate withdrawal symptoms during weaning and after extubation.Measurements and Main Results:During propofol and methohexital anesthesia, naloxone induced a 30-fold increase in epinephrine and a significant three-fold increase in norepinephrine plasma concentrations without a significant difference between groups. This increase in catecholamine plasma concentrations was associated with increased oxygen consumption and marked cardiovascular stimulation with both anesthetics, as shown by increased cardiac index, heart rate, and systolic atrial pressure whereas diastolic pressure remained unchanged. Patients receiving propofol could be extubated significantly earlier after discontinuation of the anesthetics. Although the maximum degree of withdrawal symptoms (Short Opioid Withdrawal Scale) on the day after detoxification was similar with both anesthetics, subsequent withdrawal symptoms decreased significantly more rapidly after propofol anesthesia.Conclusions:Naloxone treatment, in opioid-addicted patients, induced a marked increase in catecholamine plasma concentrations, metabolism, and cardiovascular stimulation during anesthesia with both propofol and methohexital. Although both anesthetics appear suitable for detoxification treatment, the use of propofol is associated with earlier extubation and, surprisingly, a shortened period of long-term withdrawal symptoms during detoxification.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID