摘要:

ObjectiveTo determine if measurements of gastric intramucosal pH have prognostic implications regarding ICU mortality.DesignProspective comparison of outcome.SettingGeneral adult ICUs in two teaching hospitals.PatientsEighty consecutive patients age 18 to 84 yrs (mean 63.4), 50 men and 30 women, 55% in the medical and 45% in the surgical services.MethodsGastric intramucosal pH was measured on ICU admission and again 12 hrs later. A value of ≥7.35 was used to differentiate between normal and low gastric intramucosal pH.Measurements and Main ResultsFifty-four patients had a normal gastric intramucosal pH and 26 patients had a low gastric intramucosal pH on ICU admission. The mortality rate was greater in the low gastric intramucosal pH group (65.4% vs. 43.6%;p< .04). The frequency of sepsis and the presence of multisystem organ failure also were greater in the low gastric intramucosal pH group (p< .01 ). Further stratification of patients according to gastric intramucosal pH measured 12 hrs after admission showed a greater mortality rate in patients with persistently low gastric intramucosal pH when compared with patients with normal gastric intramucosal pH during the first 12 hrs (86.7% vs. 26.8%;p< .001).ConclusionsMeasurements of gastric intramucosal pH on ICU admission, and again 12 hrs later, have a high specificity for predicting patient survival in this ICU patient population (77.8% to 80.6%). Furthermore, given its relative noninvasive nature, tonometrically measured gastric intramucosal pH may be a useful addition to patient monitoring in the ICU.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo determine the relationships among serum aminoglycoside clearance, renal aminoglycoside clearance, measured creatinine clearance, and estimated creatinine clearance derived from a standard formula in critically ill patients.SettingA ten-bed general ICU in a university hospital.PatientsEighteen critically ill patients who were being treated with gentamicin or tobramycin for severe infections, and were hemodynamically stable.InterventionsThe various clearances were measured simultaneously after the administration of a dose of aminoglycoside by assaying serial blood samples for aminoglycoside and creatinine concentration, and by measuring the content of these substances in urine collected over the same time period.Outcome measuresThe slopes, intercepts and coefficients of determination (r2) of the various regressions were determined, along with the 95% confidence intervals for the prediction of serum aminoglycoside clearance from each other variable.ResultsRenal aminoglycoside clearance, creatinine clearance, and estimated creatinine clearance accounted for only 58%, 59%, and 62%, respectively, of the variance in serum aminoglycoside clearance. Only 64% of the variance in renal aminoglycoside clearance was explained by creatinine clearance. Substantial and variable nonrenal aminoglycoside clearance was evident.ConclusionsThe 95% confidence intervals for the prediction of serum aminoglycoside clearance from each index of renal function indicated that none of these indices provided acceptable accuracy for the prediction of serum aminoglycoside clearance and dosage requirements in critically ill patients. Renal aminoglycoside clearance was no better than creatinine clearance in this respect, and thus no other index of renal function is likely to be more accurate. This finding implies that the only accurate method of determining the dose requirements to achieve target serum concentrations in such patients will be individualized pharmacokinetic dosing.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo assess the statistical association of the Acute Physiology and Chronic Health Evaluation (APACHE II) score with multiple intervention and outcome variables in surgical ICU patients.DesignContinuous data collection on every patient admitted to the surgical ICU for a 21-month period.Materials and MethodsFor every admitted patient in the surgical ICU, APACHE II scores were calculated and the relationship between APACHE II score as an independent predictor of outcome was assessed with multiple outcome variables selected for study. The outcome and intervention variables tested included: treatment intervention measures such as days on ventilator; days with an arterial catheter, central venous catheter, triple lumen catheter, pulmonary artery catheter; days receiving total parenteral nutrition; days receiving tube feedings; number of transducers per days in the ICU; number of infusion pumps per ICU days, days in the hospital, number of complete blood counts; number of electrolyte determinations; number of blood gases; number of units of blood transfused; ICU and hospital mortality rates in the presence of complications, including: respiratory distress syndrome, renal failure, congestive heart failure, coma, requirement of cardiopulmonary resuscitation, and others.ResultsThe APACHE II score was statistically associated with each intervention and outcome variable tested. Unfortunately, the associations, although consistent, were weak with r2values ranging from .03 to a maximum of 22 for Pearson's correlation coefficients.ConclusionThe APACHE II score was statistically associated with all the variables examined in our surgical patients, but its predictive power for the individual surgical patient was limited. These findings suggest that the score may be useful for retrospective analyses of large cohorts of patients but should not be used as a triage tool or as a predictor of outcome for the individual patient. Triage decisions should continue to be based on the best available clinical judgment.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo report the range of normal values for impedance-derived cardiac output, stroke volume, and the baseline transthoracic impedance in the healthy preterm and term neonate over the weight range generally found in the intensive care nursery.DesignProspective, case-referent study.SettingUniversity medical center special care and term nurseries.PatientsTwenty-seven preterm and 25 term newborns with no evidence of cardiovascular problems.InterventionsWe determined the values for impedance cardiac output and stroke volume to be used as reference values. Also measured was the baseline transthoracic impedance, a number that reflects the air/fluid ratio of the thorax.Measurements and Main ResultsStroke volume and stroke volume index were, respectively, 2.0 ± 0.8 (SD) mL and 1.4 ± 0.5 mL/kg for preterm infants, and 5.0 ± 2.0 mL and 1.6 ± 0.7 mL/kg for term neonates. Cardiac output and cardiac index were, respectively, 304 ±114 mL/ min and 214 ± 68 mL/min-kg for preterm newborns, and 648 ± 244 mL/min and 205 ± 78 mL/min-kg in term newborns. These values compared favorably with published values utilizing other techniques for these populations. Both cardiac output and stroke volume were linearly correlated to body weight, being largest in the heavier neonates. Transthoracic impedance values were 42.7 ± 9.0 ohms and 6.7 ± 1.7 ohms/cm for preterm infants and 32.3 ± 4.3 ohms and 3.9 ± 0.6 ohms/cm for term infants.Transthoracic impedance and transthoracic impedance/cm values were correlated negatively to body weight and were curvilinearly related to body weight.ConclusionsThese values for transthoracic impedance and transthoracic impedance/cm are the first reported using the standard electrode lead configuration in neonates.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Background and MethodsTumor necrosis factor (TNF) has been implicated as a major humoral mediator of sepsis and endotoxin shock. TNF is secreted by cells of the reticuloendothelial system, including alveolar macrophages. Alveolar macrophage TNF production has been postulated to play a pathogenetic role in the development of adult respiratory distress syndrome (ARDS) in sepsis. To evaluate alveolar macrophage production of TNF during sepsis and endotoxin shock, we studied the effects of sepsis and/or in vivo lipopolysac-charide on the in vitro production of TNF by pulmonary alveolar macrophages. Human pulmonary alveolar macrophages were obtained by bronchoalveolar lavage from six septic and five nonseptic patients, cultured in the presence or absence of lipopolysaccharide (1 ng/mL), and assayed for TNF activity in a bioassay using fibroblast lysis. A murine model of sepsis was also utilized to study pulmonary alveolar macrophage TNF production under more controlled conditions. Normal mice were given ip injections of either lipopolysaccharide or saline. After 2 hrs, pulmonary alveolar macrophages were obtained and cultured in saline or various concentrations of lipopolysaccharide (0.001 to 10 μg/mL).ResultsThere was no difference in baseline TNF activity, expressed as per cent lysis at 1:10 dilution, between pulmonary alveolar macrophages from control and septic patients (35.7 ± 5.5% vs. 24.4 ± 9.3%, respectively) (p> .05). However, when stimulated with lipopolysaccharide in vitro, the pulmonary alveolar macrophages from nonseptic patients produced significantly (p< .01) more TNF (82.8 ± 3.6%) than did pulmonary alveolar macrophages from patients with the septic syndrome (35.2 ± 3.8%). Similar findings were obtained using the murine sepsis model. The baseline TNF activity in pulmonary alveolar macrophages from control mice was 22.9 ± 7.0% (mean ± SEM) and from lipopolysaccharide-injected mice was 26.8 ± 3.3% (p> .05). Stimulation with 1 ng/mL lipopolysaccharide in vitro produced an increase in TNF activity in both groups, but the increase was greater in the control mice (68.1 ± 5.7%) than in the lipopolysaccharide-injected mice (47.5 ± 5.3%) (p< .01). When the murine pulmonary alveolar macrophages were stimulated with higher concentrations of lipopolysaccharide (0.1 to 10 ug/mL), pulmonary alveolar macrophages from lipopolysaccharide-injected mice produced <25.5% of the TNF produced by pulmonary alveolar macrophages from control mice.ConclusionsThese studies indicate that sepsis and endotoxin injection result in a rapid decrease in the ability of pulmonary alveolar macrophages from both humans and mice to produce and secrete TNF in response to lipopolysaccharide. We speculate that a downregulation of TNF production or of macrophage responsiveness to lipopolysaccharide has occurred. These results suggest that sustained TNF production by macrophages is not required for lung injury in sepsis.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Background and MethodsThe mechanism of ischemic bowel necrosis induced by platelet-activating factor is unclear. Since intestinal hypoperfusion is observed after platelet-activating factor injection, we hypothesized that mesenteric vasoconstriction is the mechanism of bowel injury. The present study investigated the effects of saline infusion on platelet activating factor-induced bowel necrosis and its mechanism. Male Sprague-Dawley rats were divided into four groups: group A consisted of sham-operated rats; group B received platelet-activating factor (1.5 μg/kg iv); group C received platelet-activating factor and saline (0.097 mL/min iv); group D received platelet-activating factor and WEB 2086 (platelet-activating factor antagonist).ResultsSaline infusion largely reversed platelet activating factor-induced hypotension, hemoconcentration, and reduction of the superior mesenteric arterial blood flow. Saline infusion also ameliorated platelet activating factor-induced bowel injury, although a mild-to-moderate degree of necrosis still developed focally. In addition, saline prevented the platelet activating factor-induced increase in intestinal platelet-activating factor production. Saline also prevented the increase in intestine leukocyte number, as estimated by myeloperoxidase activity.ConclusionsSaline infusion is an effective treatment for platelet activating factor-induced shock and intestinal necrosis. However, focal bowel injury is still observed, suggesting that other factors besides hemodynamic changes contribute to the development of tissue injury. We also showed that, in vivo, platelet-activating factor stimulates its own synthesis via a positive feedback loop, which could be blocked by intravascular volume expansion with saline.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Background and MethodsPentoxifylline can inhibit blood leukocyte functions in vitro, and some inflammatory processes in the lung in vivo. Therefore, we examined the effects of pentoxifylline on alveolar macrophage functions in vitro. Alveolar macrophages were harvested from normal rat lungs by airway lavage. The dose-response relationship of varying concentrations of pentoxifylline and in vitro cell functions were examined. Macrophage functions studied included adherence to nylon wool, random (unstimulated) and zymosan-activated serum-stimulated migration through 5 um millipore filters, and superoxide generation induced by zymosan-activated serum as assayed by cytochromecreduction.ResultsPentoxifylline inhibited superoxide generation and stimulated migration (but not random migration or adherence) in a dose-dependent fashion. Statistically significant inhibition was demonstrated at 0.5 mM and 5.0 mM concentrations of pentoxifylline, respectively, for stimulated migration and superoxide generation.ConclusionsPentoxifylline can inhibit some alveolar macrophage functions in vitro. These effects may inhibit some forms of inflammatory lung injury, particularly when iv infusion of high doses of pentoxifylline are utilized. However, potentially adverse effects on inflammatory defense mechanisms must be considered as well.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Editor's NoteOn behalf of the Editorial Board, I extend thanks to Drs. Meth, Harviel, and Bray for preparing this article and for providing critical care services during the Persian Gulf conflict. Many men and women in critical care participated in this military operation and this special article is published, in part, to recognize their efforts.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Central venous catheters facilitate the safe administration of parenteral nutrition and concentrated drug and electrolyte solutions, allow measurement of central venous pressures, and permit establishment of reliable venous access in patients with inadequate peripheral venous access. Unfortunately, insertion of such catheters is not risk free. Historically, numerous associated complications have been described, including arterial puncture, which has occurred in about 5% of central venipuncture attempts (range 2% to 15%) (1–5). In certain patients, classic signs of arterial puncture may be absent, and cannulation may occur. Yet, few studies have been published that document the predisposing factors, radiographie findings, and complications of accidental central arterial cannulation. Three illustrative cases are presented.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

In septic shock, hypotension is often due to peripheral vasodilation with a normal or increased cardiac output (1). In such situations, the use of vasoconstrictors to increase systemic vascular resistance may increase systemic arterial pressure and improve perfusion of the heart and other essential organs.Norepinephrine is often used in this situation for its a-adrenergic effects, but these effects often decrease with time (2). Angiotensin II is a potent vasoconstrictor whose actions are not mediated by adrenergic receptors. It has a half-life time of <2 mins. Tachyphylaxis is reportedly not a problem.The following case report describes the use of angiotensin II to increase mean arterial pressure in an adult with severe sepsis who was hypotensive despite rapid infusion rates of norepinephrine and other adrenergic drugs. We found no previous reports of the use of angiotensin II in a hemodynamically monitored patient with refractory septic shock.

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID