摘要:

ObjectiveTo evaluate the correlations between severity of illness scoring systems and biochemical markers of physiologic stress.SettingTertiary care pediatric ICU in a university hospital.DesignA prospective, clinical study.PatientsTwelve patients aged 2 to 120 months (four patients agedInterventionsOxygen consumption (±Vo2), daily total urinary nitrogen, and the branch chain to aromatic amino acid ratio were correlated with the Physiologic Stability Index, Pediatric Risk of Mortality score, and Therapeutic Intervention Scoring System. Linear regression analysis and multivariate stepwise regression analysis were used to analyze the data.Measurements and Main ResultsPediatric Risk of Mortality score and Physiologic Stability Index correlated with ±Vo2(r2= .69,p< .001 and r2= .52,p< .01, respectively) and with daily total urinary nitrogen excretion (r2= .66,p< .001 and r2= .62,p< .01, respectively). The Therapeutic Intervention Scoring System correlated with the total urinary nitrogen excretion (r2= .69,p< .001) and branch chain to aromatic amino acid ratio (r2= .49,p< .01). Correlations existed between Pediatric Risk of Mortality score and Physiologic Stability Index (r2= .88,p< .001) and Pediatric Risk of Mortality score and Therapeutic Intervention Scoring System (r2= .48,p< .01)ConclusionsThe correlations were independent of diagnostic category, suggesting that the alterations in biochemical variables were most directly related to the overall severity of illness as measured by the scoring system.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo determine daily amino acid and total protein losses in patients with acute renal failure receiving total parenteral nutrition (TPN) during treatment by continuous arteriovenous hemofiltration with hemodialysis (CAVHD).DesignProspective, nonrandomized study.SettingPatients in the ICU of a regional nephrology referral center.PatientsEight clearance studies of individual amino acids were performed in six patients with acute renal failure receiving TPN. Daily nitrogen intake was 9 g (one patient), 14 g (two patients), and 18 g (three patients). The clearances of individual amino acids were measured at two dialysis flow rates to calculate daily amino acid and total protein losses.ResultsAmino acid clearance rates ranged from 7.8 ±PT 2.2 (glutamic acid) to 25.2 ±PT 4.8 mL/min (3-methylhistidine) at a dialysate flow rate of 1L/hr and from 13.6 ±PT 1.7 (tryptophan) to 33.7 ±PT 4.3 mL/min (3-methylhistidine) at a dialysate flow rate of 2 L/hr. These results represent daily amino acid losses of 1.5 ±PT 0.4% (glutamic acid) to 111.6 ±PT 16.6% (tyrosine) of the nutritional input at a dialysate flow rate of 1 L/hr and 2.1 ±PT 0.6% (glutamic acid) to 145.8 ±PT 17.8% (tyrosine) at a dialysate flow rate of 2 L/hr. Total losses would represent 8.9 ±PT 1.2% and 12.1 ±PT 2.2%, respectively, of the daily protein input.ConclusionsThese studies confirm that amino acid clearances are relatively high during CAVHD and daily losses should therefore be considered.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo evaluate whether underlying anatomical variations in the position of the internal jugular vein may account for difficulty in obtaining central venous access in individual patients.DesignConsecutive series.SettingCardiac catheterization laboratory, coronary care unit, and ICU.PatientsTwo hundred patients (52 ±PT 7 yrs, 147 males) who were undergoing internal jugular vein cannulation for hemodynamic monitoring or endomyocardial biopsy.InterventionThe internal jugular vein and carotid artery were visualized with two-dimensional ultrasound and their position was compared with their projected location from external landmarks.ResultsIn 183 (92%) patients, the position of the internal jugular vein was lateral and anterior to the carotid artery and increased in diameter during a Valsalva maneuver. In five (2.5%) patients, the internal jugular vein was not visualized and was probably thrombosed, as the internal jugular vein was normal on the other side. In six (3%) patients, the internal jugular vein was unusually small and did not increase in diameter during the Valsalva maneuver. In two (1%) patients, the internal jugular vein was positioned >1 cm lateral to the carotid artery. Four (2%) patients had a medially positioned internal jugular vein overlying the carotid artery. In 5.5% of the patients, the position of the internal jugular vein was outside the path that had been predicted by the external landmarks.ConclusionsThese findings suggest that anatomical variation may partly account for the inability to cannulate the internal jugular vein in certain patients. In these cases, ultrasound examination quickly establishes the position of the internal jugular vein and may allow for easy and rapid access.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo examine the hemodynamic patterns of critically ill patients with septicemia to evaluate their relationship to blood bacteriology.DesignRetrospective study.SettingMedical ICUs of a tertiary care medical center.PatientsTotal of 59 critically ill patients with bacteremia: 33 with Gram-positive and 26 with Gram-negative bacteremia.MeasurementsHemodynamic variables and mixed venous oxygen saturation (SMo2) measurements associated with the highest cardiac index measured within 72 hrs of positive blood cultures.Main ResultsNo significant differences in cardiac index, mean arterial pressure, systemic vascular resistance, oxygen extraction ratio, or SMo2were observed comparing the two groups.ConclusionWe were unable to demonstrate clinically important differences between the hemodynamic responses to Gram-positive vs. Gram-negative sepsis.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo assess complications of bronchoalveolar lavage in the intubated, mechanically ventilated patient.DesignA retrospective, consecutive case series.SettingMedical, surgical, and bone marrow transplant critical care units at a university teaching hospital.PatientsNinety-nine consecutive critically ill, mechanically ventilated patients undergoing bronchoalveolar lavage were included in the study.InterventionsAll patients underwent bronchoalveolar lavage using a standard method designed to maximize the safety of the procedure.MeasurementsEach patient's hospital chart was reviewed for immediate and delayed medical complications of the procedure, including cardiac arrhythmias, bleeding, and hemodynamic disturbances. Specific indices of lung mechanics (peak inspiratory airway pressure and static compliance) and oxygenation (alveolar to arterial oxygen tension gradient [P(A-a)o2] and the ratio of F102/Pao2) were measured before and 4 hrs after bronchoalveolar lavage to assess durable physiologic consequences of the procedure.ResultsNo complications occurred that required premature termination of bronchoalveolar lavage. Three patients exhibited adverse effects (hypotension in two and wheezing in one) immediately after the procedure, all of which resolved promptly with treatment. No statistically significant changes were observed in the variables of arterial oxygenation or pulmonary mechanics. Although the sample mean did not change significantly for any of the oxygen variables, 19% of the patients experienced widening of the P(A-a)o2by >100 torr (>13.3 kPa). A systematic analysis indicated that there was no statistically significant relationship between readily available clinical variables (including duration of mechanical ventilation before bronchoalveolar lavage and prebronchoalveolar lavage P[A-a]o2), and deterioration in oxygenation after the procedure.ConclusionsWe conclude that bronchoalveolar lavage is a well-tolerated procedure in critically ill, mechanically ventilated patients, provided that risk factors for complications are corrected before the procedure and one adheres to procedural guidelines focused on patient safety. Clinically important complications are uncommon. Some patients exhibit deterioration in oxygen after bronchoalveolar lavage; this occurrence cannot be predicted before the procedure. (Crit Care Med 1991; 19:1526)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo evaluate the effects of “ego bias” on physicians' prognostic judgments. Ego bias is defined as systematic overestimation of the prognosis of one's own patients compared with the expected outcome of a population of similar patients.DesignA prospective study of an inception cohort of critically ill patients followed until death or discharge from the hospital.PatientsConsecutive patients admitted to either an ICU or an intermediate ICU at a teaching hospital during January and February 1987, excluding patients admitted after coronary artery bypass grafting, for elective dialysis, or transferred to the intermediate ICU from another critical care unit.Main Outcome Measures and ComparisonsHouse officers' and critical care attending physicians' assessments of the likelihood of inhospital survival for each patient, and their assessments of the overall survival rate of ICU and intermediate ICU patients were compared with each other and with actual survival rates.ResultsThe attending physicians' predictions for individual patients were significantly lower than their judgments of the overall survival rate, 79.8% vs. 88.0%,p= .0067, suggesting the presence of a “reverse ego bias.” The house officers' predictions for individual patients were significantly higher than their judgments of the overall survival rate, 73.5% vs. 68.9%,p= .018, suggesting the presence of ego bias. The magnitude and directions of these differences varied significantly among the attending physicians (F = 4.3, degrees of freedom = 3,p= .0062 by repeated-measures analysis of variance) and the house officers (F = 6.3, degrees of freedom = 5,p= .0001).ConclusionsThe critical care attending physicians exhibited reverse ego bias that was mainly a function of their optimism about the overall survival rate for critically ill patients. The house officers exhibited ego bias that was mainly a function of their pessimism about the overall survival rate for critically ill patients. (Crit Care Med 1991; 19:1533)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Background and MethodsIt is hypothesized that pentoxifylline may be beneficial during shock states by improving tissue oxygenation. To test this hypothesis, we examined the effect of pentoxifylline on hemodynamics, oxygen delivery (Do2), and tissue metabolism during severe hemorrhagic shock. We conducted a placebo-controlled, randomized trial using anesthetized, mechanically ventilated dogs in hemorrhagic shock maintained at a mean arterial pressure of 45 to 50 mm Hg. Six animals were treated with a 10-mg/kg bolus of iv pentoxifylline followed by a continuous infusion at 5 mg/kg-hr. The controls consisted of six animals treated with saline.ResultsThere were no significant differences between the groups before treatment. During 150 mins of posttreatment, repeated measurements of the control and pentoxifylline groups showed no significant differences in heart rate (HR), cardiac output, systemic and pulmonary vascular resistances, Do2, or blood lactate concentration (repeated-measures analysis of variance).ConclusionsIn this acute, nonresuscitated, canine hemorrhagic shock model, pentoxifylline did not act as a vasodilator, or have any significant effect on HR, cardiac output, oxygen transport, or lactic acidosis. (Crit Care Med 1991; 19:1540)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Background and MethodsWe hypothesized that β-adrenergic receptor blockade would result in an increase in serum potassium concentration in hypothermic rats given a potassium load compared to non-β-blocked, hypothermic, potassium-loaded rats. To test this hypothesis, we investigated the interaction between body temperature and β-adrenergic receptor blockade on serum potassium concentrations in ureter-ligated rats with and without potassium loading. To acheive this goal, we performed three experiments. In thefirst experiment, serum potassium concentrations were determined in 16 rats as they were continuously cooled from 37° to 22°. In thesecond experiment, 12 ureter-ligated rats were cooled to 31°, after which they were rewarmed to 37°. Serum potassium concentrations were determined before and after cooling and on rewarming. Twelve other ureterligated rats were cooled to 31°, then given a potassium load until their serum potassium concentrations returned to their baseline values, after which they were rewarmed to 37°. Serum potassium concentrations were determined before and after cooling, during the potassium infusion, and on rewarming. In thethird experiment, 14 rats were pretreated with propranolol and 14 rats served as controls. Half of the rats in each of these two groups were kept at 37° and half were cooled to 25°. All rats were then given a 690-μmol potassium chloride infusion. Serum potassium concentrations were determined before and after the potassium infusion.ResultsThe rats developed hypokalemia with cooling, which spontaneously resolved in the rats without supplementation on rewarming to 37°. The hypothermic hypokalemic rats that had their serum potassium concentrations corrected to normothermic status (2.93 ±PT 0.17 mmol/ L) had marked increases in serum potassium concentrations (4.22 ±PT 0.15 mmol/L) on rewarming. In the normothermic rats, potassium loading after β-adrenergic receptor blockade resulted in even higher serum potassium concentrations (5.65 ±PT 0.36 mmol/L) compared with non-β-blocked rats given equal potassium loads (4.6 ±PT 0.4 mmol/L). However, in hypothermic (25°) rats given the same potassium load, there was no difference in serum potassium concentrations in β-blocked (6.5 ±PT 0.35 mmol/L) and non-β-blocked rats (6.63 ±PT 0.3 mmol/L).ConclusionsThese results suggest that acute hypothermia causes a decrease in serum potassium, probably secondary to redistribution, which is reversible on rewarming. Supplementation of potassium during hypothermia can cause a significant increase in serum potassium concentration on rewarming. Blocking β-adrenergic receptors with propranolol did not effect hypothermia-induced hypokalemia, suggesting that the β-adrenergic mechanism may not be functional in hypothermia. (Crit Care Med 1991; 19:1545)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo test whether dopexamine, a dopaminergic and β2-adrenergic receptor agonist, would: a) direct a greater share of cardiac output to gut than to muscle when used to increase systemic oxygen delivery (Do2) in endotoxic dogs; and b) enhance the ability of peripheral tissues to extract oxygen.DesignTwo groups of eight dogs infused for 1 hr with 2 mg/kgEscherichia coliendotoxin. One group was continually infused with dopexamine (12 μg/min.kg) and the other group was not (control group). After 2 hrs, oxygen extracting ability was challenged by changing inspired gas to 12% oxygen for 30 mins.SubjectsAnesthetized, paralyzed, pumpventilated mongrel dogs.InterventionsDonor RBCs and dextran used during endotoxin infusion to maintain cardiac output while preserving hematocrit near 40%.Measurements and Main ResultsIn the dopexamine-treated group, cardiac output, systemic Do2, and oxygen consumption (Vo2) were higher than in the control group during the first 90 mins, but were not thereafter. Gut and muscle blood flow did not differ between groups, but the fraction of cardiac output going to each region tended to be less in the dopexamine-treated dogs. Arterial lactate values increased to about 6 mmol/L in all dogs. In both groups, limb muscle first produced lactate but then took up lactate after the first hour. The gut in controls converted from lactate uptake in the first hour to producing about 20 μmol/min.100 g, whereas the gut never produced lactate in the dopexamine-treated group. During hypoxia, systemic Do2and Vo2decreased only in the dopexamine-treated group, even though oxygen extraction was only slightly above 40%. Oxygen extraction was not demonstrably improved by dopexamine treatment.ConclusionsDopexamine temporarily increased systemic Do2and Vo2in volume-expanded endotoxic dogs during normoxia and may have caused gut mucosa to be preferentially perfused and thus to be kept better oxygenated. (Crit Care Med 1991; 19:1552)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Background and MethodsThe efficacy of using colloids vs. crystalloids in the treatment of hemorrhagic shock remains controversial. An important aspect in the treatment of hemorrhagic shock is the reestablishment of normal myocardial blood flow after fluid resuscitation. This study, therefore, was designed to investigate the effect of resuscitation with different plasma substitutes on myocardial blood flow and oxygen transport after acute hemorrhage in dogs.Forty-three dogs were anesthetized and bled into a heparinized Wiggers' reservoir to a mean arterial pressure of 35 mm Hg. The animals were maintained at this level of hypotension for 90 mins, whereupon the animals were infused with one of five randomly selected fluids: a) succinylated gelatin (Gelofusine);b) urea-linked gelatin (Haemaccel); c) 6% hetastarch (Hespan); d) lactated Ringer's solution; or e) shed blood. Myocardial blood flow was measured using the radiolabeled microsphere technique.ResultsResuscitation with succinylated gelatin, urea-linked gelatin, and hetastarch resulted in significant hemodilution. However, infusion of these fluids resulted in a compensatory hyperemia that increased myocardial blood flow and maintained oxygen transport at preshock values. No hyperemia was observed with reinfusion of shed blood. Resuscitation with lactated Ringer's solution produced significant hemodilution without hyperemia and, consequently, a significant decrease in oxygen transport.ConclusionsThese results suggest that in lieu of blood, the artificial colloids are more effective than crystalloids in restoring myocardial blood flow and oxygen transport after acute experimental hemorrhage in dogs. (Crit Care Med 1991; 19:1561)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID