摘要:

The multidimensional pathophysiology of septic shock is poorly understood and treatment modalities are controversial. The present study evaluates the relative importance of three therapeutic measures: antibiotics (trimethoprim and sulphamethovazole [TS]); fluid infusions (lactated Ringer's solution [RL] and 3% albumin [Alb]), and pharmacologic doses of corticosteroids (CS) (dexamethasone [DM]), using central hemodynamics (plasma volume [PV], cardiac output, oxygen consumption [&OV0312;O2]), and survival as end-points.Septic shock was induced by intraperitoneal injection of liveEscherichia colibacteria. At 5 h in untreated septic rats, PV had dropped to 76%, cardiac output to 69%, and &OV0312;O2to 71% of preshock levels. Untreated septic animals had a mean survival time of 9.7 ± 1.7 (SD) h, with none surviving 24 h. Regardless of therapy, cardiac output and &OV0312;O2at 10 h were predictors of survival time (p< .01). Treatment was initiated at 5.5 h after bacterial injection, at a time when TS therapy alone had not improved the 24-h survival rate. Animals treated with DM. RL, and Alb, in this order, exhibited progressively improved central hemodynamics, and 24-h survival rate increased to 60% compared with 0 in untreated animals (p< .001). The combination of DM and RL produced no further improvement. However, DM combined with 3% Alb restored &OV0312;O2cardiac output, and PV to 81%, 100%, and 125%, respectively, increasing the 24-h survival rate to 97% (29/30), significantly greater than that achieved by any other treatment modality (p< .05).

ISSN:0090-3493    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The effects of hyperoxia and superoxide dismutase (SOD) administration on endothelium-dependent relaxation induced by acetylcholine in isolated rabbit pulmonary artery (PA) preparations were examined. Relaxation responses to papaverine. and contractile responses to KCI and norepinephrine were also assessed using a bioassay technique. Prolonged hyperoxia in rabbits for 3 days produced loss of endothelium-dependent relaxation of the PA, and significant attenuation of contractile response to KCI and relaxation response to papaverine. These changes were prevented by subcutaneous SOD administration. Histological examination using light and electron microscopy revealed focal edema, destruction, and detachment of the PA endothelium in the PA strip preparations from these rabbits. Thus, it is concluded that a high concentration of oxygen exposure in rabbits for 3 days produces not only histological damage in the PA endothelium. but also causes impairment of vascular reactivity to constricting and relaxing agents. Subcutaneous SOD administration prevented oxygen-induced PA damage.

ISSN:0090-3493    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Plasma catecholamine levels rise markedly with cardiac arrest and attempted resuscitation. W e examined whether epinephrine (EPI) or norepinephrine (NE) plasma concentrations could predict resuscitation outcome. In nine mongrel dogs. EPI and NE levels were drawn before cardiac arrest and after 8 and 14 min of cardiac arrest and CPR. Intravenous EPI (1 mg) was given 1 min before the last plasma level was drawn. Catecholamines were quantitated by high-performance liquid chromatography with triple-electrode coulometric electrochemical detection. Plasma catecholamines increased significantly with cardiac arrest. EPI levels increased from a control level of 15.9 ± 3.0 to 396.0 ± 63.3 pmol/ml after 8 min of cardiac arrest (p< .05). and NE levels similarly increased from 4.4 ± 1.7 to 66.5 ± 12.0 pmol/ml (p< .01). Neither the absolute catecholamine plasma concentration nor the response to cardiac arrest of the endogenous catecholamine concentrations could predict outcome, but catecholamine responses to exogenous EPI did correlate with outcome. Animals which were subsequently resuscitated had a greater increase in the plasma EPI concentrations after exogenous EPI than animals that were not resuscitated, a 53-fold vs. a 23-fold increase (p< .05). Successfully resuscitated animals also had increased NE levels after exogenous EPI, while unsuccessfully resuscitated animals had either no change or a decrease (p< .02). Successfully resuscitated animals had an increase in coronary perfusion pressure (p< .01) in response to exogenous EPI, in contrast to those that were not resuscitated. This suggests that the exogenous administration of EPI during prolonged CPR is beneficial despite markedly elevated endogenous catecholamine levels.

ISSN:0090-3493    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Local trauma to the lungs induces a temporary permeability disturbance with reduction in the osmotic reflection coefficient of a sheep lung lymph model. Proteolytic enzymes may be involved in this microvascular injury. In the present study, we tested the hypothesis that pretreatment with methylprednisolone prevents activation of proteolytic systems after pulmonary trauma and that these systems are of etiological importance in the development of the pulmonary lesion. Central markers of proteolytic cascade systems were monitored in sheep subjected to local trauma to the lungs (lung lymph fistula preparation) with (n = 7) or without (n = 7) methylprednisolone (30 mg/kg) pretreatment. In control animals, reduced levels of prothrombin. antithrombin. kallikrein inhibitors, antiplasmin. and increased level of plasminogen activator inhibitor (PAI) indicated systemic activation of the coagulation, kallikrein-kinin, and fibrinolytic systems. These changes, except for PAI, were more pronounced in lung lymph. High levels of thromboxane A2and 6-keto prostaglandin F2were found in lymph. In steroid-pretreated animals, the prostanoid response was attenuated, but all other variables were similar to control animals; thus, steroids did not prevent either local or systemic proteolytic enzyme activation caused by local trauma to the lung. The etiological role of this activation in the development of lung lesion has not yet been evaluated.

ISSN:0090-3493    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

This paper describes the testing of a monitor (Oxyconsumeter) which uses a replenishment technique to measure oxygen consumption (VO2). Oxygen is added to the expired gas to replace the oxygen consumed by the patient. The replenishing oxygen flow equals the patient's &OV0312;O2when the mixed replenished expired oxygen fraction equals the inspired oxygen fraction. The accuracy of the Oxyconsumeter was assessed using a N2and CO2dilution technique. When tested over the operating range specified by the manufacturer, the bias of the Oxyconsumeter was 1.66% of reading. The reproducibility averaged 6.96% of reading. The reproducibility did not change with &OV0312;O2, FIO2or minute ventilation. The replenishment technique has the theoretical advantage that an absolute oxygen sensor calibration is not necessary and a respiratory flowmeter is not needed. It appears, from the laboratory testing, that the Oxyconsumeter has sufficient accuracy for use in the critical care setting.

ISSN:0090-3493    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Embolic complications of indwelling arterial lines are well documented. We evaluated a method of blood sampling from indwelling arterial lines that minimizes blood loss and eliminates the embolic risks associated with retrograde flushing. The values for PaO2, PaCO2, and pH obtained by the conventional sampling technique were compared to those obtained by a technique termed the “three drop” method. Thirty-five paired samples were obtained from patients in the pediatric ICU. Meaningful statistical and clinical correlations were observed for PaO2(r = .97,p< 10-6), PaCO2(r = .97,p< 10-6), and pH (r = .98,p< 10-6). Evaluation for the slope of the regression line for each pair of variables was also significant (p< 10-6). The means for each variable were also assessed. Only the PaCO2values were different (t= 2.49.p< .002). As the absolute value was 2 torr, we feel that there is no clinical significance to this finding. These data confirm that the three drop technique of sampling for arterial blood gas analysis is reliable. It also removes the risks of retrograde flushing and minimizes blood loss.

ISSN:0090-3493    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The purpose of the present study was to compare cardiac output (Q) values obtained by both the Kubicek (MIC) and Sramek (NCCOM3) impedance cardiographic techniques with thermodilution (TD) in critically ill patients. The two impedance techniques were also compared in normal subjects. Seven healthy subjects and ten ICU patients were enlisted in the study. Three ± measurements were made in each subject. In the ICU patients, there were no significant differences in ± values as measured by TD (6.6 L/min), MIC (6.3 L/min), and NCCOM3 (6.4 L/min). Both MIC and NCCOM3 ± values were comparable to TD in patients. In normals, however, the NCCOM3 estimated larger values for ± than did the MIC (NCCOM3. 9.2 L/min: MIC, 6.2 L/min). ± values obtained with MIC in normals were comparable with published values for supine normals. Thus, the two techniques agreed in the patients but not in the normals. The reasons for these results are not obvious from the data, but are attributable to the measurements by the NCCOM3. Because of this, caution is suggested when interpreting absolute ± values obtained by the NCCOM3.

ISSN:0090-3493    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Accessing drugs dispensed in glass ampules is always associated with glass fragment contamination of the ampule contents on opening. In this study, the glass fragment contamination from the external surface of the ampule occurred 60% of the time with 1-ml sized ampules (p< .01). Glass contamination has been shown to increase with larger ampule size. The glass ampule poses a potential source of microbial infection to the patient, as well as other hazards to the user. Increased precautions and improved drug container design appear to be desirable.

ISSN:0090-3493    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Recent studies suggest that continuous infusions of H2-receptor antagonists may be more effective than intermittent iv therapy to control gastric pH for the prevention of stress ulcers. Infusions of cimetidine. ranitidine, and famotidine have been shown either to have a beneficial clinical effect, to control gastric acid secretion, to maintain gastric pH >4, or to have pharmacokinetic properties similar to intermittent doses. In addition, some evidence suggests that continuous infusions may permit the use of lower doses, leading to cost savings. However, as yet there have been no trials that directly compare continuous and intermittent regimens and show improved outcomes with a continuous regimen.Since candidates for parenteral administration of H2-receptor antagonists are most common in the ICU, several practical issues must be addressed. Patients who receive total parenteral nutrition (TPN) may be suitable candidates for continuous infusions of H2-blockers since these agents can be given in the same container as TPN solutions. These patients also usually have a parenteral access site and infusion pump dedicated to TPN administration. In other patients, drug incompatibilities, limited iv access lines, or a lack of infusion pumps may require frequent interruptions of the infusion in order to administer additional medications, which may lead to a loss of gastric pH control. In most patients, administration of an H2-blocker regimen which maintains consistent pH control after intermittent administration may be the most practical method by which to administer these agents.

ISSN:0090-3493    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Several patients hospitalized in our 12-bed medical ICU were found to haveClostridium difficileassociated colitis. Stool cultures of all patients identified eight cases (three culture positive, and five culture and cytotoxin positive), seven of which were geographically and temporarily clustered within a 2-wk period. At least one patient appeared to contract the disease after hospitalization and in the absence of antibiotic therapy or other known major risk factors. The outbreak highlights the problem ofC. difficilein the ICU. We believe that a heightened awareness of the multiple risk factors and preventive measures, along with consideration of possible nosocomial transmission, will be necessary to prevent or arrest future clusters of cases in the ICU. The diagnosis of one patient with this infection in a unit should prompt a review of all other patients within the unit.

ISSN:0090-3493    

出版商:OVID    

年代:1989

数据来源: OVID