摘要:

Objective:To study the influence of low-dose dopexamine on splanchnic oxygenation during major abdominal surgery.Design:Prospective, randomized, placebo-controlled study.Setting:University hospital.Patients:Eighteen adult patients undergoing elective major abdominal surgery.Interventions:The patients received either dopexamine at 1 μg/kg/min (group A, n = 9) or 0.9% saline as control (group B, n = 9).Measurements and Results:To assess the splanchnic oxygenation, intestinal tissue PO2(PtissO2) and gastric intramucosal PCO2(PmucCO2) were measured, and the PCO2gap (PmucCO2− PaCO2) was calculated at baseline (T1) and after an infusion period of 60 mins (T2). There was no difference between the groups in the global oxygen transport parameters. Low-dose dopexamine increases PtissO2on the serosal side of the small bowel (ΔPtissO2, 17 ± 24 mm Hg in group A vs. −5 ± 10 in group B). The changes in PtissO2at the serosal side of the colon after dopexamine demonstrated a nonsignificant increase (ΔPtissO2, 7 ± 11 mm Hg in group A vs. −11 ± 23 mm Hg in group B). In both groups, the PCO2gap (group A, 6 ± 7 mm Hg [T1] and 5 ± 6 mm Hg [T2], vs. group B, 9 ± 10 mm Hg [T1] and 12 ± 10 mm Hg [T2]) remained unchanged compared with the baseline.Conclusion:It is concluded that low-dose dopexamine improves PtissO2at the serosal side of the gut, preferably at the small bowel. However, low-dose dopexamine did not improve gastric PmucCO2.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To determine the incidence of dialysis catheter (DC)-related infections in intensive care unit (ICU) patients, and to compare the frequency of DC and central venous catheter (CVC) infections in an ICU setting.Design:Prospective, descriptive survey.Setting:An adult, 10-bed medical/surgical ICU at a university hospital.Patients:A total of 151 DCs and 230 CVCs placed in 170 patients were evaluated.Interventions:None.Measurements and Main Results:Catheter colonization was defined by a quantitative catheter tip culture yielding ≥103colony-forming units/mL, catheter-related bacteremia was defined as catheter colonization and blood culture positive for the same organism, and site infection was defined as the presence of pus at the insertion site. The mean duration of catheterization was 6.8 ± 6 days for DCs and 5.9 ± 4.6 for CVCs (p= .52). There was no difference between DCs and CVCs in catheter colonization and catheter-related bacteremia incidence rates per 1000 days of catheter use (24.2 vs. 19.8 [p= .46] and 0.96 vs. 1.5 [p= .60], respectively). Site infection was observed in one patient (CVC placement). For DCs and CVCs the duration of catheterization was associated with catheter infection (p= .0007 andp= .04, respectively), but when the catheters were examined over 5-day intervals, the incidence of catheter infections did not increase with duration of catheter use (p= .23 andp= .10, respectively).Conclusions:DC-related infections are associated with DC longevity. As shown by the 5-day-interval analysis, the incidence of DC-related infections did not increase with DC duration, suggesting that the risk for DC-related infections remained unchanged with time. The characteristics of DC-related infections in ICU patients were comparable to those previously reported for CVC-related infections.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To evaluate the effect of acidified enteral feeds on gastric colonization in critically ill patients compared with a standard feeding formula.Design:Randomized, double-blind, multicenter trial.Setting:Eight mixed intensive care units at tertiary care hospitalsPatients:We recruited mechanically ventilated critically ill patients expected to remain ventilated for >48 hrs. We excluded patients with gastrointestinal bleeding, acidemia, and renal failure requiring dialysis. We enrolled 120 patients; 38% were female, age (mean ± SD) was 57.6 ± 19.3 yrs, and Acute Physiology and Chronic Health Evaluation II score (mean ± SD) was 21.6 ± 7.6.Interventions:Vital High Nitrogen (Abbott Laboratories, Ross Products Division, Columbus, OH) was used as the standard feeding formula for the control group (pH = 6.5). Hydrochloric acid was added to Vital High Nitrogen to achieve a pH of 3.5 in the experimental group.Measurements and Main Results:The main outcome measure was gastric colonization. Secondary outcomes included gastric pH, pneumonia, and mortality. The mean gastric pH in patients receiving acid feeds was lower (pH = 3.3) compared with controls (pH = 4.6;p< .05). One patient (2%) on acid feeds was colonized in the stomach with pathogenic bacteria, compared with 20 patients (43%) in the control group (p< .001). There was no difference in the incidence of pneumonia (6.1% in the acid feeds group vs. 15% in the control group;p= .19). Overall, there were 15 deaths in the acid feeds group and seven in the control group (p= .10); four patients in the acid feeds group and three in the control group died during the study period (pnot significant).Conclusions:Acidified enteral feeds preserve gastric acidity and substantially reduce gastric colonization in critically ill patients. Larger studies are needed to examine its effect on ventilator-associated pneumonia and mortality.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To compare two thermodilution methods for the determination of cardiac output (CO)-thermodilution in the pulmonary artery (COpa) and thermodilution in the femoral artery (COa)-with each other and with CO determined by continuous pulse contour analysis (COpc) in terms of reproducibility, bias, and correlation among the different methods. Good agreement between the methods would indicate the potential of pulse contour analysis to monitor CO continuously and at reduced invasiveness.Design:Prospective criterion standard study.Setting:Cardiac surgical intensive care unit in a university hospital.Patients:Twenty-four postoperative cardiac surgery patients.Interventions:Without interfering with standard hospital cardiac recovery procedures, changes in CO as a result of the postsurgical course, administration of vasoactive substances, and/or fluid administration were recorded. CO was first recorded after a 1-hr stabilization period in the intensive care unit and hourly thereafter for 6 hrs, and by subsequent determinations at 9, 12, and 24 hrs.Measurements and Main Results:There were 216 simultaneous determinations of COpa, COa, and COpc. COpc was initially calibrated using COa, and no further recalibration of COpc was performed. COpa ranged from 3.0 to 11.8 L/min, and systemic vascular resistance ranged from 252 to 2434 dyne·sec/cm5. The mean difference (bias) ±2 SD of differences (limits of agreement) was −0.29 ± 1.31 L/min for COpa vs. COa, 0.07 ± 1.4 L/min for COpc vs. COpa, and −0.22 ± 1.58 L/min for COpc vs. COa. In all but four patients COpc correlated with COa after the initial calibration. Correlation and precision of COpc vs. COa was stable for 24 hrs.Conclusions:Femoral artery pulse contour CO correlates well with both COpa and COa even during substantial variations in vascular tone and hemodynamics. Additionally, CO determined by arterial thermodilution correlates well with COpa. Thus, COa can be used to calibrate COpc.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objectives:To investigate the concentrations of mononuclear cell-associated ceramide and serum tumor necrosis factor-α (TNF-α) in patients with sepsis and to assess their predictive value for the development of multiple organ dysfunction syndrome (MODS).Design:Prospective, cohort study.Setting:Intensive care unit and two research laboratories at a university hospital.Patients:Twenty-three adult patients admitted to an intensive care unit meeting the criteria for diagnosis of sepsis.Interventions:Blood samples were collected at the time when diagnosis of sepsis was made.Measurements and Main Results:Mononuclear cell-associated ceramide and serum TNF-α were significantly elevated in the samples from the septic patients compared with the control individuals (318.01 ± 270.15 pmol/106cells vs. 99.90 ± 52.75 pmol/106cells;p< .001, and 28.52 ± 18.77 pg/mL vs. 10.43 ± 3.37 pg/mL;p< .0001, respectively), and a direct correlation linked ceramide and TNF-α concentrations (r2= .90,p< .00001). In the septic patients who went on to develop MODS, ceramide and TNF-α were significantly higher compared with the no MODS patients (489.22 ± 264.93 pmol/106cells vs. 131.23 ± 99.02 pmol/106cells;p< .0001, and 40.96 ± 18 pg/mL vs. 14.95 ± 5.60 pg/mL;p< .001, respectively). The receiver operating characteristic curves demonstrated that both TNF-α and ceramide were prognostic of MODS, but ceramide concentrations were more efficient predictors.Conclusions:These observations suggest that mononuclear cells of peripheral blood from patients with sepsis are committed to undergo apoptosis, because there is evidence that ceramide acts as an endogenous mediator of apoptosis. The strong correlation we found between cell-associated ceramide and serum TNF-α supports the hypothesis that this cytokine plays an important role in activating the sphingomyelin pathway and ceramide generation in patients with sepsis. In addition, this study provides evidence that consistent concentrations of mononuclear cell-associated ceramide may predict progression toward MODS in septic patients.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To determine the prevalence of hypotestosteronemia in chronically critically ill (CCI) men.Design:Prevalence survey.Setting:Step-down respiratory care unit (RCU) at a tertiary care teaching hospital.Patients:Thirty ventilator-dependent CCI men transferred from intensive care units (ICUs) within the same institution.Interventions:None.Measurements and Main Results:Total testosterone and bioavailable testosterone (bioT) concentrations were measured within 48 hrs of RCU admission. Patients were hospitalized a median of 40 days (range, 9-185 days) before RCU admission, with a median ICU length of stay of 25 days (range, 9-177 days). At RCU admission, total testosterone concentrations averaged 104 ± 96 ng/dL, with average bioT concentrations of 19 ± 20 ng/dL (16 ± 9% of total testosterone). Twenty-nine of the 30 patients (96%) had bioT concentrations well below the lower limit of normal for their age range. bioT concentrations, expressed as a percentage of the normal mean for each patient's age range, were positively correlated with the number of days that the patient was in the ICU before transfer to the RCU (n = 30, r2= .17,p= .025). However, if the single patient who remained in the ICU for 177 days was excluded, this correlation disappeared (n = 29, r2= .07,p= .09). No other relationship was found between bioT concentrations and any other variable, including type of patient, ICU length of stay, reason for either initial admission to the ICU or prolonged mechanical ventilation, type of nutritional support, or use of dopamine.Conclusions:CCI men have a very high prevalence of hypotestosteronemia, which may impede their recuperation and rehabilitation. Further studies are needed to determine whether additional pharmacologic treatment with testosterone can improve the recovery of these patients.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To test the hypothesis that, in decompensated chronic obstructive pulmonary disease (COPD), noninvasive pressure support ventilation using 70:30 helium:oxygen instead of 70:30 air:oxygen could reduce dyspnea and improve ventilatory variables, gas exchange, and hemodynamic tolerance.Design:Prospective, randomized, crossover study.Setting:Medical intensive care unit, university tertiary care center.Patients:Nineteen patients with severe COPD (forced 1-sec expiratory volume of 0.83 ± 0.3 l) hospitalized in the intensive care unit for noninvasive pressure support ventilation after initial stabilization with noninvasive pressure support for no more than 24 hrs after intensive care unit admission.Interventions:Noninvasive pressure support ventilation was administered in the following randomized crossover design: a) 45 min with air:oxygen or helium:oxygen; b) no ventilation for 45 min; and c) 45 min with air:oxygen or helium:oxygen.Measurements and Main Results:Air:oxygen and helium:oxygen decreased respiratory rate and increased tidal volume and minute ventilation. Helium:oxygen decreased inspiratory time. Both gases increased total respiratory cycle time and decreased the inspiratory/total time ratio, the reduction in the latter being significantly greater with helium:oxygen. Peak inspiratory flow rate increased more with helium:oxygen. PaO2increased with both gases, whereas PaCO2decreased more with helium:oxygen (values shown are mean ± SD) (52 ± 6 torr [6.9 ± 0.8 kPa] vs. 55 ± 8 torr [7.3 ± 1.1 kPa] and 48 ± 6 torr [6.4 ± 0.8 kPa] vs. 54 ± 7 torr [7.2 ± 0.9 kPa] for air:oxygen and helium:oxygen, respectively;p< .05). When hypercapnia was severe (PaCO2> 56 torr [7.5 kPa]), PaCO2decreased by ≥7.5 torr (1 kPa) in six of seven patients with helium:oxygen and in four of seven patients with air:oxygen (p< .01). Dyspnea score (Borg scale) decreased more with helium:oxygen than with air:oxygen (3.7 ± 1.6 vs. 4.5 ± 1.4 and 2.8 ± 1.6 vs. 4.6 ± 1.5 for air:oxygen and helium:oxygen, respectively;p< .05). Mean arterial blood pressure decreased with air:oxygen (76 ± 12 vs. 82 ± 14 mm Hg;p< .05) but remained unchanged with helium:oxygen.Conclusion:In decompensated COPD patients, noninvasive pressure support ventilation with helium:oxygen reduced dyspnea and PaCO2more than air:oxygen, modified respiratory cycle times, and did not modify systemic blood pressure. These effects could prove beneficial in COPD patients with severe acute respiratory failure and might reduce the need for endotracheal intubation.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To determine whether a correlation exists between concentrations of intracellular and extracellular potassium and to determine the frequency of ventricular ectopy in patients after cardiac operations.Design:Prospective, observational clinical evaluation.Setting:Surgical-respiratory intensive care unit of a university-affiliated tertiary care center.Patients:Continuous 24-hr electrocardiographic monitoring was performed, and serum (extracellular) and erythrocyte (intra-cellular) potassium concentrations ([K+]eand [K+]i) were determined, before cardiopulmonary bypass, immediately postoperatively, and at 2, 4, 12, and 20 hrs after elective coronary bypass grafting in 31 patients.Interventions:None. Potassium replacement was left to the discretion of the attending physicians.Measurements and Main Results:Although the mean [K+]evaried significantly during the postoperative 24-hr period (p< .0001), the [K+]idid not (p= .953). No significant correlations were found between premature ventricular beats and [K+]i, [K+]e, or [K+]i/[K+]e(allp> .05). However, among the few patients who had one or more episodes of ventricular tachycardia (VT) within 30 mins of a study K+sample, the mean [K+]ewas significantly lower during the episode(s) of VT compared with the mean [K+]ein the absence of VT (p< .01).Conclusions:Although it is clear that over the clinically acceptable range of [K+]eand [K+]iconcentrations seen in this population, there is no correlation between potassium concentrations and the occurrence of premature ventricular beats, the infrequent association of more serious ventricular ectopy, VT, with lower [K+]econcentrations supports the practice of using serum potassium to guide potassium replacement in patients after cardiac operations.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To evaluate accuracy and repeatability of blood volume determinations made by the carbon monoxide method, using a ventilator-driven administration system.Design:Prospective within-patient comparison, using simultaneous measurements by two methods to determine accuracy. Prospective laboratory investigation in animals to estimate repeatability.Subjects:For accuracy: Nineteen ventilated critically ill patients in a university hospital intensive care unit. For repeatability: Six anesthetized, mechanically ventilated normovolemic pigs because this is impossible to perform in humans.Interventions:In the accuracy study, a small mass of carbon monoxide was administered via a closed breathing system and arterial blood samples were taken from existing cannulas. In the repeatability study, an intramuscular sedative was given, followed by an inhalational anesthetic induction and mechanical ventilation via a tracheal tube. Left axillary artery and external jugular vein cannulas were sited. Anesthesia was maintained using an intravenous infusion. Five sequential circulating hemoglobin and blood volume estimations were made using the carbon monoxide method.Measurements and Main Results:The small carboxyhemoglobin increase produced by uptake of a small, known mass of carbon monoxide was used to estimate the circulating blood volume. Simultaneous measurement, using51Cr-labeled red blood cells, was performed.Twenty measurements were made in 19 patients. The bias (mean difference between blood volume measurements by the two methods) was 397 mL (5.53 mL·kg−1) ±415 mL (±5.95 mL·kg−1); the limits of agreement (mean difference ±2 SD) were −433 mL and 1227 mL (−6.36 mL·kg−1and 17.42 mL·kg−1). Therefore, 95% of expected differences will lie between these limits. The mean blood volume was 75.8 mL·kg−1in the animals. The coefficient of variation of repeated estimates was 9.49%. Mean circulating hemoglobin mass was 7.31 mmol with a coefficient of variation of 10.18%. The mean hemoglobin concentration, by co-oximetry, was 5.014 mmol·L−1, coefficient of variation, 2.99%.Conclusion:This arrangement is a potential bedside method of estimating blood volume and circulating hemoglobin mass. We have rendered the technique more acceptable clinically by creating a ventilator-driven administration system.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To determine whether hydrocortisone given intravenously inhibits reactive oxygen species (ROS) generation by polymorphonuclear neutrophils (PMNLs)in vivoand, if so, to describe the pharmacodynamics of this effect.Design:A prospective, open label study in normal subjects.Setting:A clinical research unit of a tertiary referral center for diabetes and endocrinology.Patients:Eight normal subjects (age range, 24-50 yrs).Intervention:An indwelling cannula was inserted into the antecubital vein. Sequential blood samples were obtained from the cannula just before, and after, the intravenous injection of hydrocortisone (100 mg) at 1, 2, 4, 8, and 24 hrs.Measurements and Main Results:ROS generation by PMNLs and mononuclear cells (MNCs) was assayed as previously observed in a chemiluminometer. ROS generation by PMNLs and MNCs was inhibited by hydrocortisone at 1 hr; this effect peaked at 2 hrs and began to recover by 4 hrs; ROS generation had recovered to the baseline by 24 hrs. Although the pharmacodynamic effect of hydrocortisone on PMNLs and MNCs was similar, the peak inhibition was significantly greater for PMNLs (26% of basal vs. 43% of basal,p< .02) than MNCs.Conclusions:There is a marked, consistent, inhibition of ROS generation by PMNLs, which parallels that of MNCs after intravenous hydrocortisone. The pharmacodynamics of this effect are consistent with our current clinical practices.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID