摘要:

ObjectiveDuring nitric oxide inhalation, methemoglobinemia needs to be monitored. We compared six commercially available instruments and one manual method for methemoglobin measurements. In addition, we studied whether and to what degree methylene blue interferes with methemoglobin measurements.DesignIn vitro methodologic study.SettingResearch laboratory in a university hospital.PatientsFive healthy volunteers from whom red blood cells were obtained.InterventionsMethemoglobinemia was generated in a red blood cell suspension by nitric oxide; methemoglobin was measured with six commercial instruments and one manual photometric method to calculate variation coefficients and to determine the differences between the devices. Methemoglobin was measured with and without the addition of methylene blue with two instruments. Measurements were performed immediately after the addition of methylene blue.Measurements and Main ResultsAll six commercially available instruments had variation coefficients of <0.1 at methemoglobin concentrations of 5%, whereas the manual photometric method did not reach a variation coefficient of <0.1 at 8% of methemoglobin. Apart from two devices that measured slightly but significantly higher methemoglobin levels, all instruments measured similar values of methemoglobin when the same samples were determined simultaneously. Higher concentrations of methylene blue (10, 40, 100 [micro sign]M) reduced substantially the apparent concentrations of methemoglobin. Interference by methylene blue was most pronounced at low methemoglobin levels.ConclusionsWith some limitations, all commercial instruments that were tested performed adequately for the monitoring of methemoglobinemia. Methylene blue interferes with the methemoglobin measurements in a dose-dependent manner. (Crit Care Med 1999; 27:1191-1194)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundGiven the high costs of delivering care to critically ill patients, practitioners and policymakers are beginning to scrutinize the costs and outcomes associated with intensive care. Health economics is a discipline concerned with determining the best way of using resources to maximize the health of the community. This involves addressing questions such as which procedure, test, therapy, or program should be provided, and to whom, given available resources.PurposeThe purpose of this article is to review general economic principles that will help intensivists to better interpret published economic evaluations.Data SourcesSelected articles from the health economics and critical care literature.ResultsIn this article, we use an economic evaluation that examines sedation strategies in critically ill patients. We discuss how learning to critically appraise an economic evaluation is only part of the task for end users. Determining whether and how to apply the results of economic evaluations to local settings presents bigger challenges and remains largely a matter of judgment.ConclusionsEconomic evaluations use analytic techniques to systematically consider all possible costs and consequences of clinical actions. Although they should never form the sole basis for clinical decisions for individual patients, economic evaluations offer potentially useful information at different levels of decision-making. (Crit Care Med 1999; 27:1195-1202)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo provide a meta-analysis of current literature concerning the validation of thoracic impedance cardiography (TIC) and to explain the variations in the reported results from the differences in the studies.Data SourcesA computer-assisted search of English-language, German, and Dutch literature was performed for the period January 1966 to April 1997. Moreover, references from review articles were obtained.Study SelectionA total of 154 studies comparing measurements of cardiac output or related variables obtained from TIC and a reference method were analyzed.Data ExtractionArticles were classified by differences in TIC methodology, reference method, and subject characteristics. Fisher's Zftransformed correlation coefficients were used to compare results. Data were pooled using the random-effects method.Data SynthesisAn overall pooled r2value of.67 (95% confidence interval, 0.64-0.71) was found. However, the correlation was higher in repeated-measurement designs than in single-measurement designs (r2= .53; 95% confidence interval, 0.43-0.62). Further research using analysis of variance revealed a significant influence of the reference method and the subject characteristics on the correlation coefficient. The correlation was significantly better in animals than in cardiac patients. Subgroup analysis revealed that TIC correlated significantly better to the indirect Fick method than to echocardiography in healthy subjects. No significant influence of the applied TIC methodology was found.DiscussionThe overall r2value of.67 indicates that TIC might be useful for trend analysis of different groups of patients. However, for diagnostic interpretation, a r2value of.53 might not meet the required accuracy of the study. Great care should be taken when TIC is applied to the cardiac patient. However, because the applied reference method was of significant influence, differences between TIC and the reference method are incorrectly attributed to errors in TIC alone. (Crit Care Med 1999; 27:1203-1213)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Bronchiolitis obliterans organizing pneumonia and erythema nodosum are immunologic diseases that have not been reported to occur together.We report the case of a lady who developed bronchiolitis obliterans organizing pneumonia and erythema nodosum simultaneously, several weeks after smoke inhalation in a house fire. (Crit Care Med 1999; 27:1214-1216)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID