摘要:

Objective:The diagnosis of infection in critically ill patients is challenging because traditional markers of infection are often misleading. For example, serum concentrations of calcitonin pre-cursors are increased in patients with infections. However, their predictive accuracy for the diagnosis of sepsis in unselected patients in a medical intensive care unit (ICU) is unknown. Therefore, we compared the usefulness of serum concentrations of calcitonin precursors, C-reactive protein, interleukin-6, and lactate for the diagnosis of sepsis in consecutive patients suffering from a broad range of diseases with an anticipated stay of ≥ 24 hrs in a medical ICU.Design:Prospective cohort study.Setting:Medical intensive care unit in a university medical center.Patients:101 consecutive critically ill patients.Intervention:None.Measurements and Main Results:Blood samples were collected at various time points during the course of the disease. Systemic inflammatory response syndrome, sepsis, severe sepsis, and septic shock were diagnosed according to standardized criteria, and patients were reclassified daily without prior knowledge of the serum concentrations of calcitonin precursors or interleukin-6. At admission, 99% of the patients had systemic inflammatory response syndrome, 53% had sepsis, and 5% developed sepsis during their stay in the ICU. Calcitonin precursors, C-reactive protein, interleukin-6, and lactate levels increased with the severity of infection (p< .01, one-way analysis of variance). In a receiver operating characteristic curve analysis, calcitonin precursors were found to be the most reliable laboratory variable for the diagnosis of sepsis as compared with C-reactive protein, interleukin-6, and lactate (p< .01, for each comparison). Calcitonin precursor concentrations of > 1 ng/mL had sensitivity of 89% and specificity of 94% for the diagnosis of sepsis. High serum concentrations of calcitonin precursors were associated with poor prognosis (p= .01).Conclusions:In a medical ICU, serum calcitonin precursor concentrations are more sensitive and are specific markers of sepsis as compared with serum C-reactive protein, interleukin-6, and lactate levels.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To develop a scheme for early identification of individuals at risk for symptomatic vasospasm after subarachnoid hemorrhage (SAH).Design:Analysis of prospectively collected data from the placebo-treated group in a multicenter clinical trial.Settings:Fifty-four neurosurgical centers in North America.Measurements and Main Results:We identified independent predictors of symptomatic vasospasm using stepwise logistic regression analysis from demographic, clinical, laboratory, and neuroimaging characteristics of the participants. We developed a scoring system (symptomatic vasospasm risk index) based on a combination of these predictors. Out of 283 patients in the analysis (all treated with oral nimodipine), 93 (33%) developed symptomatic vasospasm within 14 days after SAH. There were four independent predictors of symptomatic vasospasm: thickness of subarachnoid clot on computed tomographic scan (odds ratio [OR], 4.1; 95% confidence interval [CI], 1.8-10.0); early rise in middle cerebral artery mean flow velocity (MCA-MFV), defined as a value ≥110 cm/sec recorded on or before post-SAH day 5 (OR, 1.9; 95% CI, 1.1-3.3), Glasgow Coma Scale score <14 (OR, 1.8; 95% CI, 1.1-3.1); and rupture of anterior cerebral or internal carotid artery aneurysm (OR, 1.9; 95% CI, 1.0-3.4). The probability of identifying patients who would develop symptomatic vasospasm (percentage of area under receiver operating characteristics curve ± SEM) was higher with symptomatic vasospasm risk index (68% ± 8%) compared with thickness of clot (62% ± 8%;p= .08) or MCA-MFV (45% ± 7%,p< .05) criteria alone.Conclusions:Patients at high risk for symptomatic vasospasm can be identified early in the course of SAH using a risk index. A risk index based on a combination of variables may represent a predictive paradigm superior to conventionally used criteria based on clot thickness or MCA-MFV criteria.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To test the hypothesis that the prevalence of hyperhomocysteinemia is increased in critically ill patients and correlates with disease severity and mortality in these patients.Design:A prospective study.Setting:Three medical intensive care units at the University of Vienna Medical School serving both medical and surgical patients.Patients:All consecutive admissions (n = 56) during a period of 4 wks. A total of 112 age- and gender-matched healthy individuals constituted the control group.Interventions:None.Measurements and Main Results:Blood samples were drawn within 24 hrs after admission for analysis of total homocysteine (tHcy), folate, vitamin B6levels, and vitamin B12levels as well as to identify the 677C→T polymorphism in the gene coding for the enzyme 5, 10-methylenetetrahydrofolate reductase. Acute Physiology and Chronic Health Evaluation III scores at admission and 24 hrs after admission as well as 30-day survival were documented in all patients. Hyperhomocysteinemia was more prevalent in critically ill patients (16.1%; 95% confidence interval, 7.6% to 28.3%) compared with age- and gender-matched healthy individuals (5.4%; 95% confidence interval, 2.0% to 11.3%; chi-square test;p= .022). There was no difference in tHcy plasma concentrations in the first 24 hrs after admission to an intensive care unit between survivors and nonsurvivors. The 5,10-methylenetetrahydrofolate reductase 677C→T polymorphism had no influence on tHcy levels and survival of intensive care unit patients.Conclusions:The prevalence of hyperhomocysteinemia is increased in critically ill patients compared to age- and gender-matched healthy individuals. The clinical significance of this finding remains to be determined.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To evaluate whether changes in cardiac output influence cerebral perfusion directly. In fulminant hepatic failure, the circulation is characterized by wide variations in cardiac output and cerebral blood flow (CBF).Design:A retrospective, interindividual analysis of CBF and cardiac output (part 1) and a prospective evaluation of cerebral perfusion, cardiac output, and arterial pressure during norepinephrine infusion (part 2).Setting:A four-bed specialist liver failure unit.Patients and Interventions:Twenty patients with fulminant hepatic failure (median age, 43 yrs; range, 17-54; 13 women) maintained on mechanical ventilation (PaCO2, 33 torr [4.40 kPa]; range, 26-36 torr [3.47-4.80 kPa) after development of hepatic encephalopathy, stages 3 to 4, had mean arterial pressure (MAP) and cardiac output determined by radial and pulmonary artery catheters. Cerebral perfusion was measured by the133Xenon clearance technique (n = 8) and by transcranial Doppler sonography, which was used to measure mean flow velocity (Vmean). CBF and Vmeanin patients with high cardiac output (>9 L/min) were compared with those with normal or low cardiac output. In the second part of the study, cerebral autoregulation was evaluated by concomitant measurement of Vmean, cardiac output, and MAP during norepinephrine infusion in nine patients.Measurements and Main Results:Median cardiac output was 8.5 L/min (range, 3.2-17.3), CBF was 33 mL/100 g/min (12-77 g/min), and Vmeanwas 45 cm/sec (22-65 cm/sec). In patients with elevated cardiac output, MAP, Vmean, and CBF were similar compared with patients with normal cardiac output. Neither CBF nor Vmeancorrelated to cardiac output. During norepinephrine infusion, Vmeanincreased from 49 cm/sec (34-69 cm/sec) to 63 cm/sec (58-90 cm/sec;p< .05), as MAP increased from 75 mm Hg (54-105 mm Hg) to 97 mm Hg (90-128 mm Hg). On average, cardiac output remained unchanged at 5.7 L/min (range, 3.2-17.3), as it increased in five patients and decreased in four patients. The change in Vmeanwas related to MAP (r2= .76;p< .01) but not to cardiac output (r2= .01).Conclusion:This study shows that CBF correlates to arterial pressure rather than to cardiac output in patients with fulminant hepatic failure. The presence of pressure-passive cerebral circulation stresses the importance of strict cardiovascular control in securing continuous and sufficient cerebral oxygenation and in avoiding the development of cerebral hyperemia and cerebral edema.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objectives:Neutrophils play an important role in ridding the body of bacteria and cellular debris. Several neutrophil functions are thought to be regulated by inotropes that increase cellular levels of cyclic adenosine monophosphate, including phosphodiesterase (PDE) inhibitors. We have investigated the effect of amrinone, milrinone, and olprinone, type III PDE (PDE-III) inhibitors, on several human neutrophil functions.Design:Prospectivein vitrostudy.Setting:Academic research laboratory.Subjects:Neutrophils isolated from 12 healthy adult volunteers.Interventions:We measured chemotaxis, phagocytosis, reactive oxygen species production, intracellular calcium ion concentration, and cyclic adenosine monophosphate levels in neutrophils in the absence and the presence (at clinically relevant concentrations, 10 times, and 100 times those concentrations) of amrinone, milrinone, or olprinone. We also measured reactive oxygen species production under the same condition in a xanthine-xanthine oxidase systemMeasurements and Main Results:None of the PDE-III inhibitors impaired neutrophil chemotaxis or phagocytosis. Amrinone at clinically relevant or higher concentrations and milrinone at high concentrations reduced superoxide, hydrogen peroxide, and hydroxyl radical levels in neutrophils and in the xanthine-xanthine oxidase system. Olprinone did not have those effects, and none of the PDE-III inhibitors had an effect on intracellular calcium ion concentration or cyclic adenosine monophosphate production in neutrophils stimulated by a chemotactic factor.Conclusions:The ability of amrinone to scavenge reactive oxygen species at clinically relevant concentrations while not affecting neutrophil function suggests that the PDE inhibitor can be used without detriment in severely ill patients.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To assess whether variables such as unit occupancy and aggregate severity of illness that reflect increased work demands on physicians in medical intensive care units (MICU) are associated with increased delays in their obtaining information about nonroutine chest radiographic examinations. To determine whether the presence of a picture archiving and communication system (PACS) workstation in the MICU shortens those delays.Design:A prospective cohort study stratified for presence or absence of PACS.Setting:MICU of a university hospital.Patients:A total of 118 patients admitted to the MICU who had nonroutine bedside chest radiographs.Measurements and Main Results:Multivariate analyses were conducted to determine how unit occupancy, patient acuity, the time of day the examination was taken, and the presence of a PACS workstation influenced the time from radiographic examination completion to the time when MICU physicians first obtained image information.In a multivariate analysis, patient acuity, unit occupancy, the aggregate level of severity of illness in the study cohort, whether the examination was taken at night or day, and the presence of a PACS workstation were significant predictors of the elapsed time from examination completion until review by MICU physicians. Without the PACS workstation, higher occupancy, higher aggregate severity of illness, and examinations taken during the day were associated with longer delays. Overall, the multivariate analysis showed a 24-min decrease in the elapsed time to obtain information during periods with the PACS workstation compared with periods without the workstation (p= .03).Conclusions:A PACS workstation significantly decreased the delays in obtaining image information that occurred with high unit occupancy and high aggregate severity of illness and may improve unit efficiency under conditions of high physician workload.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To identify outcome predictors in bone marrow transplantation (BMT) patients admitted to the intensive care unit (ICU) of The University of Texas M. D. Anderson Cancer Center who required endotracheal intubation and mechanical ventilation.Design:Retrospective, comparative study.Setting:A 16-bed medical intensive care unit in a university teaching cancer center.Patients:The records of 60 consecutive BMT patients who developed respiratory failure requiring mechanical ventilation were reviewed.Interventions:None.Measurements and Main Results:The most frequent complication leading to respiratory failure was pneumonia (41%) followed by diffuse alveolar hemorrhage (37%). Eighteen percent of the patients were extubated and discharged from the ICU, but only 5% were alive at 6 months. Graft vs. host disease was a predictor of a poor outcome (p< .05). Breast cancer as an underlying disease and pulmonary edema as a complication were favorable predictive factors (p< .05). Five of 26 patients with diffuse alveolar hemorrhage and four of 33 patients with pneumonia survived. We found no relationship between survival and age, gender, BMT type, or Acute Physiology and Chronic Health Evaluation II score. Prolonged mechanical ventilation (≥15 days) and late development of respiratory failure (>30 days after BMT) were associated with poor prognosis.Conclusions:The ICU survival rate of BMT patients who developed pulmonary complications and required mechanical ventilation was 18%. Prognostic factors were described identifying patients with a substantial survival rate as well as those in whom mechanical ventilation was futile.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To measure the pressure-flow relationship of pediatric endotracheal tubes (ETTs) in trachea models, to mathematically describe this relationship, and to evaluate in trachea/lung models a method for calculation of pressure at the distal end of the ETT (Ptrach) by subtracting the flow-dependent pressure drop across the ETT from the airway pressure measured at the proximal end of the ETT.Design:Trachea models and trachea/lung models.Setting:Research laboratory in a university medical center.Interventions:The pressure-flow relationship of pediatric ETTs (inner diameter, 2.5-6.5 mm) was determined using a physical model consisting of a tube connector, an anatomically curved ETT, and an artificial trachea. The model was ventilated with sinusoidal gas flow (12-60 cycles/min). The coefficients of an approximation equation considering ETT resistance and inertance were fitted separately to the measured pressure-flow curves for inspiration and expiration. Calculated Ptrachwas compared with directly measured Ptrachin mechanically ventilated physical trachea/lung models.Measurements and Main Results:The pressure-flow relationship was considerably nonlinear and showed hysteresis around the origin caused by the inertia of accelerated gas. ETT inertance ranged from 0.1 to 0.4 cm H2O/L·sec2(inner diameter, 6-2.5 mm). The abrupt change in cross-sectional area at the tube connector caused an inspiration-to-expiration asymmetry. Calculated and measured Ptrachwere within ± 1 cm H2O. Correspondence between measured and calculated Ptrachis improved even further when the ETT inertance is taken into account.Conclusions:Ptrachcan continuously be monitored in the presence of pediatric ETT by combining ETT coefficients and the flow and airway pressure continuously measured at the proximal end of the ETT.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:Patients with acute bacterial meningitis are often treated with sympathomimetics to maintain an adequate mean arterial pressure (MAP). We studied the influence of such therapy on cerebral blood flow (CBF).Design:Prospective physiologic trial.Setting:The Department of Infectious Diseases, Copenhagen University Hospital, Denmark.Patients:Sixteen adult patients with acute bacterial meningitis.Intervention:Infusion of norepinephrine to increase MAP.Measurements:During a rise in MAP induced by norepinephrine infusion, we measured relative changes in CBF by transcranial Doppler ultrasonography of the middle cerebral artery, recording mean flow velocity (Vmean), and by the arterial to jugular oxygen saturation difference. In 10 out of 16 patients, serial measurements were performed until recovery or death. Individual autoregulation curves were analyzed by a computer program. Autoregulation was classified as impaired if Vmeanincreased by >10% per 30 mm Hg increase in MAP and if no lower limit of autoregulation was identified by the computer program; otherwise, autoregulation was classified as preserved.Main Results:Initially, Vmeanincreased from a median value of 46 cm/sec (range, 30-87 cm/sec) to 63 cm/sec (33-105 cm/sec) (p< .0001), and arterial to jugular oxygen saturation difference decreased from 0.28 (0.16-0.51) to 0.21 (0.08-0.39) (p< .001) when MAP was raised from 69 mm Hg (55-102 mm Hg) to 110 mm Hg (93-129 mm Hg). CBF autoregulation was restored in eight of ten patients undergoing serial examination after 7 (range, 2-10) days. Six of these patients had an uncomplicated course, one had a protracted recovery, and one died. Autoregulation was not restored in two patients; one died and one had a protracted recovery.Conclusion:In patients in the early phase of acute bacterial meningitis, CBF autoregulation is impaired. With recovery from meningitis, the cerebral vasculature regains the ability to maintain cerebral perfusion at a constant level despite variations in MAP.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:The efficiency of secondary thoracic computed tomography (TCT) in critically ill patients with multiple traumas was assessed by comparison of TCT with chest radiograph findings. The subsequent therapeutic consequences based on the additional information of TCT were evaluated.Setting:A six-bed trauma intensive care unit in a university hospital.Design:Prospective, descriptive study.Patients and Interventions:One hundred one computed tomographic (CT) examinations (mean, 2.6 per patient; range, 1-10) were performed in 39 patients, fulfilling the following indications for TCT: a) sepsis with suspected pulmonary focus (n = 41); b) deterioration of pulmonary gas exchange (n = 35); c) guiding the duration of intermittent prone positioning (n = 25). The information provided by TCT was compared with corresponding chest radiographs (CXR). Therapeutic consequences drawn after TCT were compared with the additional diagnostic information of TCT. The change of therapy was documented that would not have been undertaken or may have been delayed had TCT evaluation not been used.Results:TCT was significantly superior to CXR in detecting pneumothoraces, pleural effusions, and pulmonary abscesses. Furthermore, a significantly higher accuracy regarding pulmonary densities was found. Subsequent therapeutic interventions ensued from 85 (84.2%) CT scans. After TCT, intermittent prone positioning was initiated in 31 patients, chest tubes were inserted in 16 patients, and intermittent prone positioning was terminated in 13 patients and was continued in 12 patients. Eleven thoracotomies were performed because of the TCT findings. The described therapeutic interventions were based on abnormalities seen on CT scans but were not evident in CXR in 58 patients (57.4%). Significant information that influenced therapeutic concepts was obtained in 66% (n = 23) of patients with pulmonary deterioration of gas exchange, in 61% (n = 25) of patients with sepsis, and in 40% (n = 10) of patients to guide the duration of intermittent prone positioning. Thoracotomy and specific drainage by tube thoracostomy was always dependent on the findings of TCT.Conclusion:Performed under the above displayed defined indications, TCT had an overall efficiency of 57%. It provided an increased sensitivity for intrathoracic lesions and a more comprehensive diagnosis of chest abnormalities.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID