PubMed Health⌕ Search

Biomedical subjects

W J Sibbald

Publications and source records attributed to W J Sibbald.

At least 37 records · Page 2Linked to original sources
PubMed2000

Diaspirin cross-linked Hb and norepinephrine prevent the sepsis-induced increase in critical O(2) delivery.

We hypothesized that support of arterial perfusion pressure with diaspirin cross-linked Hb (DCLHb) would prevent the sepsis-induced attenuation in the systemic O(2) delivery-O(2) uptake relationship. Awake septic rats were treated with a chronic infusion of DCLHb or a reference treatment [norepinephrine (NE)] to increase mean arterial pressure by 10-20% over 18 h. Septic and sham control groups received normal saline. Isovolemic hemodilution to create anemic hypoxia was then performed in a metabolic box during continuous measurement of systemic O(2) uptake. O(2) delivery was calculated from hemodynamic variables, and the critical point of O(2) delivery (DO(2 crit)) was determined using piecewise regression analysis of the O(2) delivery-O(2) uptake relationship. Sepsis increased DO(2 crit) from 4.99 +/- 0.17 to 6.69 +/- 0.42 ml x min(-1) x 100 g(-1) (P < 0.01), while O(2) extraction capacity was decreased (P < 0.05). DCLHb and NE infusion prevented the sepsis-induced increase in DO(2 crit) [4.56 +/- 0.42 ml x min(-1) x 100 g(-1) (P < 0.01) and 5.04 +/- 0.56 ml x min(-1) x 100 g(-1) (P < 0.05), respectively]. This was explained by a 59% increase in O(2) extraction capacity in the DCLHb group compared with septic controls (P < 0.05), whereas NE treatment decreased systemic O(2) uptake in anemic hypoxia (1.51 +/- 0.08 vs. 1.87 +/- 0.1 ml x min(-1) x 100 g(-1) in septic controls, P < 0.05). We conclude that DCLHb ameliorated O(2) extraction capacity in the septic microcirculation, whereas NE decreased the metabolic demands of the tissues.

Animals↗
PubMed1999

Dopexamine attenuates flow motion in ileal mucosal arterioles in normotensive sepsis.

OBJECTIVES: Injury to the small intestine is thought to play a crucial role in the development and propagation of sepsis. Cellular hypoxia, caused by hypoperfusion, may result in increased mucosal permeability, thus allowing the translocation of bacteria and endotoxin to the circulation. The purpose of this study was to assess the effect of the synthetic catecholamine, dopexamine, on the mucosal microcirculation of the septic rat ileum. DESIGN: Randomized, crossover study. SETTING: Teaching hospital animal laboratory. SUBJECTS: Sprague-Dawley male rats. INTERVENTIONS: Sepsis was induced by cecal ligation and perforation in 11 male Sprague-Dawley rats. Six sham animals were also studied. At 24 hrs, rats were anaesthetized, intubated, ventilated, and prepared for intravital microscopy of the mucosal surface of the ileum. Dopexamine (8 microg/kg/min) and saline were infused intravenously into each rat using a randomized crossover design. MEASUREMENTS AND MAIN RESULTS: Observations were videotaped for later analysis of arteriolar flow patterns, red cell velocity, arteriolar diameter, and intercapillary area. All values are expressed as mean +/- SEM. The main effect of dopexamine infusion in the sepsis group was the attenuation of the rhythmic blood flow patterns (flow motion) observed during saline infusion. In each subject, dopexamine decreased the absolute number of arterioles exhibiting flow motion by 35.93+/-6.81% (p<.001, paired t-test). Dopexamine decreased the amount of time red cell flow was stopped in marginal and central arterioles by 11.83+/-2.49% (p<.001, paired t-test). Dopexamine did not alter significantly the diameter of the marginal arterioles, the intercapillary area, or the red cell velocity compared with saline in the sepsis group. The sham group displayed marked microvascular differences compared with the sepsis group with respect to arteriolar diameter (13.32+/-0.05 vs. 9.46+/-0.24 mm, p<.001), intercapillary area (975.93+/-60.60 vs. 1256.03+/-43.88 mm2, p<.05 ), red cell velocity (611.40+/-38.77 vs. 289.15+/-36.45, p<.001), and blood flow patterns (% displaying flow motion, 15.89+/-6.09 vs. 58.22+/-9.63, p<.01; % time stopped flow, 1.96+/-0.89 vs. 20.21+/-3.92, p<.005). CONCLUSIONS: These results indicate that dopexamine increased overall blood flow and possibly oxygen delivery to the mucosa by altering patterns of blood flow within the villi. The observation that the diameter of the marginal arterioles is not affected by dopexamine indicates that dopexamine influences the mucosal microcirculation at the level of higher order arterioles. We conclude that sepsis results in abnormal microvascular villus blood flow and that dopexamine can partially restore these changes towards normal.

Animals↗
PubMed1999

How to use articles about diagnostic technology: gastric tonometry.

PURPOSE: Periodic diagnostic tests and continuous and intermittent monitoring are integral to critical care medicine. The focus of this article is understanding the impact of existing diagnostic technology, as well as that of new diagnostic technology. DATA SYNTHESIS: We use literature about gastric tonometry to illustrate eight steps for assessing the value of diagnostic technology. METHODS: These steps focus on how the technology works in the laboratory, its range of uses and diagnostic accuracy, its impact on healthcare workers, the decision making process, and patient outcomes, as well as issues of access, cost, and application in your own setting. CONCLUSIONS: Awareness of the scope and quality of research evaluating new and existing diagnostic technology is central to modern critical care practice.

Canada↗
PubMed1999

Interobserver variability in data collection of the APACHE II score in teaching and community hospitals.

OBJECTIVES: To examine interobserver reliability of the Acute Physiologic and Chronic Health Evaluation (APACHE) II score and identify major causes of variability in data collection. DESIGN: Descriptive, comparative analysis. SETTING: Nine intensive care units in two teaching and six community hospitals SUBJECTS: A random sample of 342 patient records selected from a network database. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Data were reabstracted and compared with the original records. Individual physiologic points derived from the APACHE II scoring system (instead of the actual physiologic values) were compared using the kappa statistic. Paired measurements of the continuous variables were compared using the interclass correlation coefficient and Bland-Altman plots. Excellent agreement was found in most demographic, admission, and discharge data. The system failure requiring intensive care unit admission was consistently identified by both data collectors in 88% of cases, but only 66% agreed on the exact admitting diagnosis. For APACHE II score components, the kappa statistic ranged from 0.315 for the Glasgow Coma Scale point to 0.976 for the age point. Significant disagreement regarding the probability of death derived from the APACHE II model was evident in some patient records. Overall agreement among groups of patients regarding the APACHE II score was good, however, with no significant difference in the mean score (20.2 vs. 20.1; p = .758). The predicted mortality from the reabstracted data was 30%, similar to the 27% predicted mortality from the original data (p = .380). CONCLUSION: Reliability of data collection varied widely in different components of the APACHE II probability-of-death model. Significant discrepancies in some components suggested a lack of explicit definitions and timing for consistent data collection between institutions or between data collectors. Nonetheless, variability resulting from data collection appears to be randomly distributed, so that comparisons of group means are valid.

APACHE↗
PubMed1999

Is there a preferred technique for weaning the difficult-to-wean patient? A systematic review of the literature.

OBJECTIVE: To answer the following question: In difficult-to-wean patients, which of the three commonly used techniques of weaning (T-piece, synchronized intermittent mandatory ventilation, or pressure support ventilation) leads to the highest proportion of successfully weaned patients and the shortest weaning time? DATA SOURCES: Computerized literature searches in MEDLINE (1975-1996), Cinahl (1982-1996), and Healthplan (1985-1996), exploding all Mesh headings pertaining to Mechanical Ventilation and Weaning. Searches were restricted to the English language, adults, and humans. Personal files were hand searched, and references of selected articles were reviewed. STUDY SELECTION: a) POPULATION: Patients requiring a gradual weaning process from the ventilator (either requiring prolonged initial ventilation of >72 hrs or a failed trial of spontaneous breathing after >24 hrs of ventilation); b) INTERVENTIONS: At least two of the following three modes of weaning from mechanical ventilation must have been compared: T-piece, synchronized intermittent mandatory ventilation, or pressure support ventilation; c) OUTCOMES: At least one of the following: weaning time (time from initiation of weaning to extubation) or successful weaning rate (successfully off the ventilator for >48 hrs); and d) STUDY DESIGN: Controlled trial. DATA EXTRACTION: Two reviewers independently reviewed the articles and graded them according to their methodologic rigor. Data on the success of weaning and the time to wean were summarized for each study. DATA SYNTHESIS: The search strategy identified 667 potentially relevant studies; of these, 228 had weaning as their primary focus, and of these, 48 addressed modes of ventilation during weaning. Only 16 of these 48 studies had one of the specified outcomes, and only ten of these were controlled trials. Of the ten trials, only four fulfilled all our selection criteria. The results of the trials were conflicting, and there was heterogeneity among studies that precluded meaningful pooling of the results. CONCLUSIONS: There are few trials designed to determine the most effective mode of ventilation for weaning, and more work is required in this area. From the trials reviewed, we could not identify a superior weaning technique among the three most popular modes, T-piece, pressure support ventilation, or synchronized intermittent mandatory ventilation. However, it appears that synchronized intermittent mandatory ventilation may lead to a longer duration of the weaning process than either T-piece or pressure support ventilation. Finally, the manner in which the mode of weaning is applied may have a greater effect on the likelihood of weaning than the mode itself.

Controlled Clinical Trials as Topic↗
PubMed1999

Microvascular perfusion deficits are not a prerequisite for mucosal injury in septic rats.

Our major objective was to investigate whether injury to the mucosa of the small intestine occurred in a normotensive model of sepsis and whether such injury was associated with microvascular perfusion deficits. Using fluorescence intravital microscopy, we show direct evidence of cell injury within the mucosa (pneumonia 12.4 +/- 2.6 cells/field, sham 2.2 +/- 0.7 cells/field), whereas use of 51Cr-labeled EDTA showed evidence of increased mucosal permeability (pneumonia 1.90 +/- 0.67 ml. min-1. 100 g-1; sham 0.24 +/- 0.04 ml. min-1. 100 g-1), 48 h following induction of pneumonia. Despite such injury the capillary density in the ileal mucosa and submucosa of pneumonic rats (1,027 +/- 77 and 1,717 +/- 86 mm2) was not significantly different compared with sham (998 +/- 63 and 1,812 +/- 101 mm2). However, a modest albeit significant decrease in capillary perfusion was measured in the muscularis layer of pneumonia (11.0 +/- 1.3 mm) compared with sham (13.9 +/- 0.63 mm) and appeared to be associated with leukocyte entrapment. Pretreatment using low doses of endotoxin to induce endotoxin tolerance not only increased muscularis capillary density but reduced the number of leukocytes trapped within the microvasculature, decreased myeloperoxidase activity within the ileum in pneumonic rats, and prevented mucosal injury. In conclusion, we have shown that pneumonia results in remote injury to the mucosa of the ileum and that such injury was not associated with concurrent mucosal perfusion deficits.

Animals↗
PubMed1999

Effects of FI(O(2)) on hemodynamic responses and O(2) transport during RSR13-induced reduction in P(50).

Reduced Hb-O(2) affinity facilitates O(2) release to tissue but may impair pulmonary O(2) uptake, affecting cardiac output and systemic vascular resistance (SVR). We studied the effects of shifting the O(2)-dissociation curve (ODC) to the right with a continuous infusion of RSR13, an allosteric modifier of Hb, and of different inspired O(2) fractions (FI(O(2))) on arterial O(2) saturations (Sa(O(2))) in Hb and on hemodynamics in nonanesthetized rats. At an FI(O(2)) of 0.21, Sa(O(2)) fell during RSR13 from 95 to 81%. Elevation of FI(O(2)) to 0.30 returned Sa(O(2)) to baseline in the RSR13 group. The decrease in mean arterial pressure (MAP) was significantly greater in the control than in the RSR13 group at 30% O(2). Cardiac index (CI) increased only during RSR13 at 21% O(2) and returned to baseline at 30% O(2). In contrast, SVR decreased after RSR13 was infused at 21% O(2) but returned to baseline at 30%O(2), whereas controls showed the opposite, a sustained SVR. In the follow-up period, when 21 O(2)% was reestablished and mild anemia was present, MAP and SVR fell significantly more in controls, whereas CI only increased in controls. Lactate was significantly lower in the RSR13 than in the control group during RSR13 and the follow-up period. These results demonstrate that 1) continuous infusion of RSR13 produces a constant shift in the O(2) tension at which Hb is 50% saturated (P(50)), 2) FI(O(2)) of 0.30 compensates for the effects of increased P(50) on pulmonary O(2) loading, and 3) right-shifted ODC combined with supplemental O(2) may improve tissue O(2) availability.

Aniline Compounds↗
PubMed1999

LPS pretreatment ameliorates peritonitis-induced myocardial inflammation and dysfunction: role of myocytes.

Peritonitis induced by cecal ligation and puncture (CLP) produces a systemic inflammatory response that can be largely mitigated by pretreatment of the animals with lipopolysaccharide (LPS tolerance). Although cells of myeloid origin and endothelial cells have been shown to contribute to the development of LPS tolerance, little is known regarding the potential role of parenchymal cells in this phenomenon. The major aim of the present study was to assess whether cardiac parenchymal cells (myocytes) contribute to the development of LPS tolerance. Six hours after induction of CLP rats were neutropenic and acidotic, the myocardium contained a leukocyte infiltrate [myeloperoxidase (MPO) activity was increased], and myocardial contractile function was impaired (left ventricular developed pressure was decreased). In animals that were pretreated with LPS these manifestations of sepsis were largely reversed. Further studies focused on the responses of cardiac myocytes to CLP and whether myocytes contributed to the development of LPS tolerance. Myocytes were isolated from rat hearts 6 h after induction of CLP. These myocytes 1) exhibited an impaired ability to shorten in response to pacing, 2) contained the nuclear transcription factor NF-kappaB in their nuclei, 3) increased their surface levels of intercellular adhesion molecule-1 (ICAM-1), and 4) were hyperadhesive for neutrophils. All of these events did not occur in myocytes obtained from animals that were pretreated with LPS before induction of CLP. These findings indicate that LPS tolerance can be induced in myocytes with respect to polymorphonuclear leukocyte adhesion, presumably by an inability of CLP to mobilize NF-kappaB to the myocyte nuclei and, thereby, preventing an increase in surface levels of ICAM-1.

Animals↗
PubMed1999

Effects of modest anemia on systemic and coronary circulation of septic sheep.

Although a lower transfusion trigger is generally recommended, little evidence is available about the physiological mechanisms of mild anemia in diseases with an imbalance between O2 supply and O2 demand such as sepsis. This study was undertaken to describe the systemic and coronary metabolic O2 reserve in an awake sheep model of hyperdynamic sepsis comparing two different hemoglobin levels. Twenty-four hours after sheep were rendered septic by cecal ligation and perforation (CLP), blood transfusion (n = 7, hemoglobin = 120 g/l) and isovolemic hemodilution (n = 8, hemoglobin = 70 g/l), respectively, were performed. Another 24 h later, we measured hemodynamics, organ blood flows, and systemic and myocardial O2 metabolism variables at baseline and through four stages of progressive hypoxia. Maximum coronary blood flow was 766.3 +/- 87.4 ml. min(-1). 100 g(-1) in hemodiluted sheep group versus 422.7 +/- 53.7 ml. min(-1). 100 g(-1) in the transfused sheep (P < 0.01). Myocardial O2 extraction was higher in the transfusion group (P = 0.03) throughout the whole hypoxia trial. In the hemodilution group, coronary blood flow increased more per increase in myocardial O(2) uptake than in transfused sheep (P < 0.01). This was accompanied by a lower left ventricular epicardial-to-endocardial flow ratio in hemodiluted sheep (1.13 +/- 0.07) than in transfused sheep (1.34 +/- 0.02, P < 0.05). We conclude that the lower coronary blood flow and greater myocardial O2 extraction in transfused septic sheep preserves transmyocardial O2 metabolism better in comparison to hemodiluted sheep.

Anemia↗
PubMed1999

Effects of isoproterenol on myocardial structure and function in septic rats.

In this study we sought to determine the effect of sepsis on two sequelae of prolonged (24-h) beta-agonist administration, myocardial hypertrophy and catecholamine-induced cardiotoxicity. Sprague-Dawley rats were randomized to cecal ligation and perforation (CLP) or sham study groups and then further randomized to receive isoproterenol (2.4 mg. kg-1. day-1 iv) or placebo treatment. At 24 h, myocardial function was assessed by using the Langendorff isolated-heart technique or the heart processed for plain light microscopy. We found that 1) sepsis reduced contractile function, indicated by a rightward shift in the Starling curve (ANOVA with repeated measures, sepsis effect, P < 0.002); 2) sepsis-induced myocardial depression was reversed by isoproterenol treatment (isoproterenol effect, P < 0.0001); 3) sepsis reduced, but did not block, isoproterenol-induced myocardial hypertrophy (isoproterenol effect, P < 0.0001); 4) sepsis did not protect the heart from catecholamine-induced tissue injury; 5) the septic heart was protected against the effects of ischemiareperfusion (decreased postreperfusion resting tension, ANOVA with repeated measures, P < 0.01), an effect attenuated by isoproterenol treatment (P < 0.005); and 6) sepsis reduced the incidence of sustained asystole or ventricular fibrillation after ischemia-reperfusion (P < 0.05), an effect also attenuated by isoproterenol treatment (P < 0.01). We conclude that, in sepsis, beta-agonists induce changes in myocardial weight and function consistent with acute myocardial hypertrophy. These changes occur at the expense of significant tissue injury and increased sensitivity to ischemia-reperfusion-induced tissue injury.

Adrenergic beta-Agonists↗
PubMed1999

Pressure ulcer prevention: a randomized controlled trial of 2 risk-directed strategies for patient surface assignment.

OBJECTIVE: To compare the clinical utility, in terms of incidence of pressure ulcer (PU) development, and economic impact of 2 programs of patient surface assignment for PU prevention. DESIGN: Randomized controlled clinical trial with economic evaluation. SETTING: 30-bed multidisciplinary intensive care unit (ICU), serving as the regional trauma center. PATIENTS: 144 consecutive eligible patients at risk for the development of PUs. INTERVENTION: PU risk was assessed on admission using the Skin Ulcer Risk Evaluation (SURE) Score, and patients were randomized to either the experimental (purchase) or control group (purchase/rent). Based on their SURE Score, patients were assigned a specialty surface if needed. Patients received head-to-toe skin assessments twice weekly, new PUs were documented, a new SURE Score was calculated, and specialty surfaces were upgraded or downgraded as necessary. OUTCOMES: The incidence of PUs by site and severity, and cost. ANALYSES: Multivariate logistic regression and decision modeling. RESULTS: No significant differences were detected between groups with respect to baseline population characteristics, nor in the development of PUs. Predictors of PU development were ICU length of stay and SURE Score. The experimental (purchase) group was the less costly strategy. Under baseline assumptions, surface costs per at-risk patient were $76 CDN and $171 CDN in the experimental and control groups, respectively. The savings of $95 CDN per at-risk patient translates into conservative annual savings of $47,500 CDN. CONCLUSIONS: Using an objective, risk-based method of patient surface assignment, the authors compared the clinical and economic outcomes of 2 programs of PU prevention. In a direct comparison of alternatives, the strategy that emphasized purchased rather than rented products proved to be the more economical. Finally, this approach illustrates how by prospectively capturing data on both the costs and consequences of competing alternatives, a more objective and informed decision-making process can result.

Aged↗
PubMed1998

Ventilatory care in a selection of Ontario hospitals: bigger is not necessarily better! Critical Care Research Network (CCR-Net).

OBJECTIVE: To determine whether there is variability in the structure and process of ventilatory care in intensive care units (ICUs) of the hospitals of Southwestern Ontario. DESIGN: Self-administered questionnaire-based survey. SETTING: ICUs of selected community and teaching hospitals of Southwestern Ontario. PARTICIPANTS: Head of respiratory therapy service of respective hospitals; in those hospitals without respiratory therapists, the ICU nurse manager. INTERVENTION: Self-administered questionnaire. OUTCOME MEASURE(S): The availability of different models of ventilators and respiratory therapist and physician coverage were assessed. In addition, the use of clinical practice guidelines, respiratory therapists, and the nursing role in ventilatory care were determined. RESULTS: In general, the structure of ventilatory care, including availability of different modes of ventilation, and coverage by respiratory therapists and physicians was more comprehensive in larger hospitals. However, the availability of some modes of ventilation varied more than expected among hospitals of comparable size. Similarly, variability in the process of ventilatory care, defined by the availability of clinical practice guidelines and the roles of respiratory therapists varied both within and among hospitals of different size. CONCLUSIONS: The structure and process of ventilatory care in this sample of Southwestern Ontario ICUs was found to be variable. Not all this variability could be accounted for by hospital size, suggesting a potential for improvement in overall ventilatory care. Further study is required before any specific recommendations can be considered.

Critical Care↗
PubMed1998

Some opinions on the future of evidence-based medicine.

Clinicians who introduced evidence-based medicine (EBM) argued for an approach to medical practice and teaching based on knowledge of the evidence upon which practice is founded and on the strength of the evidence itself. This article reviews the impetus for the design and growth of EBM, defines and examines the paradigm of EBM, and offers some opinions on the future of EBM in critical care.

Critical Care↗
PubMed1998

Withdrawal and withholding of life support in the intensive care unit: a comparison of teaching and community hospitals. The Southwestern Ontario Critical Care Research Network.

OBJECTIVES: To compare the incidence of withdrawal or withholding of life support (WD/WHLS), and to identify similarities and differences in the process of the withdrawal of life support (WDLS) between teaching and community hospitals' intensive care units (ICUs). DESIGN: Prospective cohort study, with some data obtained by retrospective chart review. SETTING: The ICUs of three teaching hospitals and six community hospitals. PATIENTS: All patients who died in these nine ICUs over a 6-mo period. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Data on admitting diagnosis, cause of death, mode of death (death despite active treatment, withdrawal or withholding of life support), those initiating and involved in WDLS, and modalities of life support withdrawn were gathered for patients dying in the ICU over a 6-mo period. One hundred sixty patients in community hospitals and 292 in teaching hospitals died in their respective ICUs over the 6-mo period. We found a difference in the distribution of mode of death between community hospitals and teaching hospitals, resulting from a greater proportion of patients dying as a result of withholding life support in community hospitals (11.9% vs. 3.8% withheld, respectively, p = .004). Among the six community hospitals and three teaching hospitals, we found a difference in the proportion of patients dying despite active treatment compared with those dying as a result of WD/WHLS (p = .042 and p = .044, respectively). Initiation of WDLS by physicians was more frequent at teaching hospitals (81% vs. 61%, p = .0005), while families more commonly initiated WDLS at community hospitals (34% vs. 19%, p = .005). A greater proportion of patients in teaching hospitals were receiving mechanical ventilation (99% vs. 89%) and vasopressors (76% vs. 65%) before WDLS. Similar proportions had mechanical ventilation withdrawn (68% and 74%, community hospitals and teaching hospitals, respectively), while there was a trend for fewer patients in community hospitals to have vasopressors withdrawn (56% vs. 70%, p = .082). The time to death after WDLS had begun was longer in community hospitals compared with teaching hospitals (0.74 +/- 1.38 days vs. 0.27 +/- 0.79 [SD] days, p = .0028). CONCLUSIONS: The incidence of WD/WHLS was similar in community hospitals and teaching hospitals; however, withholding of life support was more common in community hospitals. The process of WDLS appears to differ between community hospitals and teaching hospitals.

Adult↗
PubMed1998

Patients readmitted to the intensive care unit during the same hospitalization: clinical features and outcomes.

OBJECTIVE: To determine the clinical features and outcomes of patients readmitted to the intensive care unit (ICU) during the same hospital stay and the causes for these readmissions. DESIGN: Multicenter, cohort study. SETTING: Three ICUs from two teaching hospitals and four ICUs from four community hospitals. PATIENTS: All ICU admissions were collected prospectively for a registry database in the seven ICUs. We retrospectively analyzed ICU admissions between January 1, 1995 and February 29, 1996. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: During the study period, 236 (4.6%) of the patients discharged alive from the ICU were readmitted to the unit. Patients with gastrointestinal (GI) and neurologic diagnoses had the highest readmission rate. Of the readmissions, 45% had recurrence of the initial disease, 39% experienced new complications, and 14% required further planned operation. Among patients readmitted for the same illness, cardiovascular and respiratory problems were the most frequent diagnoses. Of patients readmitted with a new diagnosis, 30% initially had GI diseases, while respiratory diseases accounted for 58% of the new complications. Readmissions within 24 hrs occurred in 27% of all readmissions. Patients requiring readmission had a higher hospital mortality rate (31.4%) compared with those not requiring readmission (4.3%, p < .001), even after adjustment for disease severity score (odds ratio = 5.93, p < .001). CONCLUSIONS: Patients with GI and neurologic diseases are at greatest risk of requiring ICU readmission. Respiratory diseases are the major reason for readmission due to new complications. Readmitted patients have a high risk of hospital death that may be underestimated by the usual physiologic indicators on either initial admission or readmission. Further studies are required to determine if patients at risk for readmission can be identified early to improve the outcome.

APACHE↗
PubMed1998

Selective gut microcirculatory control (SGMC) in septic rats: a novel approach with a locally applied vasoactive drug.

Gut mucosal hypoperfusion plays a major role in the pathogenesis of ongoing sepsis and multiple organ dysfunction syndrome. Traditionally, therapy included increasing systemic flow, thus secondarily augmenting blood flow to the gut. Direct manipulation of the gut mucosal microcirculation avoiding systemic effects, i.e., selective gut microcirculatory control (SGMC), has not been tested with a clinically available vasodilating drug. We hypothesized that a topically applied vasoactive drug would affect gut mucosal microcirculation without systemic effects. Twelve Sprague-Dawley rats were randomly assigned to cecal ligation and perforation (CLP), or sham (SC) laparotomy. Twenty-four hours after surgery, mucosal arterioles of a 3-4 cm exteriorized ileal segment were studied using intravital microscopy while suffused with saline followed by sodium nitroprusside (SNP, 100 microg/mL, 3.4 mM). SNP normalized (to SC saline values, 14.5 +/- .6 microm) the CLP arteriolar diameters, from 11 +/- 6 to 14.6 +/- .3 microm (p < .05), while mean arterial pressure (MAP) was stable. Flowmotion patterns were also normalized by SNP, and intercapillary areas (i.e., diffusion distance) were decreased. We conclude that SNP exerted beneficial effects on gut mucosal microcirculation without affecting MAP; therefore, SGMC may be a novel way to affect the course of sepsis.

Administration, Topical↗
PubMed1998

Leukocyte activation and flow behavior in rat skeletal muscle in sepsis.

In animal models of endotoxemia, sepsis is associated with the accumulation of leukocytes and altered microvascular perfusion. In order to test the hypothesis that bacterial sepsis upregulates leukocyte-endothelial adhesion, we used intravital microscopy to examine the flow behavior of leukocytes in the postcapillary venules (PCV) of rats made septic by cecal ligation and perforation (CLP). Animals were randomized to CLP or sham study groups and studied 6 h, 24 h, or 48 h later. In postcapillary venules of the extensor digitorum longus muscle, we found that: (1) over the course of the study, leukocyte adhesion and extravasation increased in both experimental groups (analysis of variance [ANOVA], significant time effect: adhesion, p < 0.001; extravasation, p < 0.05); (2) leukocyte adhesion was decreased by CLP treatment (ANOVA, sepsis effect, p = 0.05), particularly after 24 to 48 h of sepsis (ANOVA, sepsis x time interaction, p < 0.05); and (3) the reduction in leukocyte adhesion in CLP animals was associated with a decrease in leukocyte extravasation (ANOVA, sepsis effect, p < 0.01). After correction for the reduction in systemic leukocyte count associated with CLP, the effect of sepsis on leukocyte adhesion and extravasation no longer reached statistical significance. These findings suggest that chronic (6 to 48 h) bacterial sepsis does not upregulate leukocyte adhesion in a manner similar to that seen in models of acute endotoxemia. These data suggest that the increased microcirculatory flow heterogeneity seen in this and other models of bacterial sepsis may not be explained by leukocyte entrapment in postcapillary venules.

Acute Disease↗