Recent blood gas analysis as emergency testing

Laboratory specimen tests, histological exams, physiological tests and image diagnoses are routinely conducted on medical premises. These include emergency specimen testing such as hematological exams, partial biochemical exams and partial immunology exams. Emergency tests, especially those carried out by doctors and nurses in the operating theatre, nurse's station and bedside are called Point Of Care Tests or Near Patient Tests. The purpose is to facilitate quick, accurate diagnosis, thereby increasing the effectiveness of critical care. POCT/NPT was started due to an increasing requirement in the USA for faster turnaround times, and made possible with the development of high quality portable medical devices with sensor technology. In this article, the history and most recent information, diagnosis and treatment using Blood Gas Analysis, a mandatory test for critically ill patients, is described.     

Point of care testing from clinical laboratory

The point of care testing(POCT) becomes popular in the Japanese medical scenes. POCT has its unique technologies which makes convenient and fast turn around time(TAT) test available to the physicians. Can clinical laboratories challenge to this new technologies? The licensed medical technologists and clinical laboratory analyzers with advanced user interface improve TAT, and the well established technology can provide the best solution today, and. The synergy of the clinical laboratory tests and POCT will increase the productivity of patient care in the future.     

The rise and fall of i-STAT point-of-care blood gas testing in an acute care hospital

In response to a $350,000 laboratory budget cut and closure of an intensive care unit-based laboratory and a desire to maintain turnaround times of 10 minutes or less, a multidisciplinary group developed and implemented point-of-care (POC) testing. Only blood gases (pH, PO2, and PCO2) and ionized calcium values were deemed essential stat tests. Three commercially available POC blood gas devices were evaluated; all yielded results comparable to in-house reference methods. The 1 device with a US Food and Drug Administration-approved method for ionized calcium testing and with an existing interface for laboratory information systems was selected. Fiscal analysis predicted annual savings of approximately $225,000. POC blood gas analysis was implemented in April 1996 coincident with closure of the intensive care unit-based laboratory. Clinical laboratories and POC blood gas test volumes remained constant through August 1998; in contrast, the number of ionized calcium tests decreased dramatically after April 1996. In August 1998, clinically significant (i.e., artificial ventilation parameters would have been altered based on test results) discrepant PCO2 values were observed sporadically and noted only with patient specimens, not with commercial controls or electronic simulators. Because investigation failed to identify the cause, use of the POC device was discontinued in September 1998.     

血液电解质自动分析仪临床性能分析

本文主要从临床应用角度对血液电解质自动分析仪的线性、准确度和精度进行了分析。     

Reasons for proficiency testing failures in clinical chemistry and blood gas analysis: a College of American Pathologists Q-Probes study in 665 laboratories

OBJECTIVE: To determine the reasons for proficiency testing (PT) failures from 41 chemistry and blood gas analytes using data collected to benchmark performance. DESIGN: Self-administered survey requesting number of challenges by analyte encompassing nine PT events. When the challenge resulted in a self-defined failure, further information was requested concerning the magnitude of the failure (as a standard deviation index) and categorization of the type of failure into six major groups (Methodologic, Technical, Clerical, Survey, Unexplained, or Other) and then into subgroups. PARTICIPANTS: Laboratories enrolled in the 1992 College of American Pathologists Q-Probes program. MAIN OUTCOME MEASURES: Rate of PT failures and reasons for failure. RESULTS: Proficiency testing data from 670,489 challenges performed in 665 laboratories revealed 9268 (1.4%) unacceptable results. Failure types were distributed as follows: Methodologic, 33.5%; Technical, 17.4%; Clerical, 11.1%; Survey, 7.8%; Unexplained, 25.7%; and Other, 7.4%. CONCLUSIONS: Individual analyte PT failure is a common event in the participating laboratories, but failures in successive or alternate events are rare. Analysis of the reasons for failed events indicates that most identified reasons occurred in either the Methodologic or Technical categories (50.9%). Analysis of the failure types suggested investigation pathways based on the magnitude of the failure that could reduce the 25.7% rate of unexplained failures.     

重症监护室2154例新生儿血电解质分析及临床意义

目的探讨重症监护室新生儿电解质紊乱的类型及发生率之间的关系,指导临床治疗.方法患儿入室后立即取桡动脉血0.1ml,采用美国i-STAT便携式血气分析仪测定血电解质,以后根据病情再复查血电解质.结果 2154例患儿共4073例次血电解质测定中,有1244例(57.75%)共1739例次伴不同类型的电解质紊乱,其中低钠血症368例,高钠血症7例,低钾血症273例,高钾血症79例,低钙血症388例,高钙血症215例,且与原发病有关.结论对危重新生儿血电解质进行动态监测,提高了诊断的准确性,极大地提高了抢救成功率.     

Contemporary testing for enteric pathogens: the potential for cost, time, and health care savings.

We sent a questionnaire to 79 clinical microbiology laboratories seeking information on contemporary practices when investigating for bacterial and protozoan enteric pathogens. Data from the 67 respondents (response rate of 85%) showed that a minority of laboratories (40% for stool culture and 45% for ova and parasite [O&P] examinations) had restrictions for testing in place and that fewer laboratories (24% for stool culture and 19% for O&P examinations) rejected specimens from patients who had been in the hospital for > 3 days. Using two estimates, 15 and 40%, for the proportion of all specimens received from patients in the hospital for > 3 days, we calculated savings for the average hospital in this survey. Reagent savings of $4,000 to $10,000 and time savings of 274 to 731 h per year might have been realized. Moreover, between $26,000 and $71,000 in patient charges could have been prevented. On the basis of this survey, wider application of rejection criteria when testing for enteric pathogens appears possible. If implemented, savings to the nation's health care system could be between $27 and $73 million a year.     

Utilization of arterial blood gas measurements in a large tertiary care hospital

We describe the patterns of utilization of arterial blood gas (ABG) tests in a large tertiary care hospital. To our knowledge, no hospital-wide analysis of ABG test utilization has been published. We analyzed 491 ABG tests performed during 24 two-hour intervals, representative of different staff shifts throughout the 7-day week. The clinician ordering each ABG test was asked to fill out a utilization survey. The most common reasons for requesting an ABG test were changes in ventilator settings (27.6%), respiratory events (26.4%), and routine (25.7%). Of the results, approximately 79% were expected, and a change in patient management (eg, a change in ventilator settings) occurred in 42% of cases. Many ABG tests were ordered as part of a clinical routine or to monitor parameters that can be assessed clinically or through less invasive testing. Implementation of practice guidelines may prove useful in controlling test utilization and in decreasing costs.     

Smoking induced changes in EEG two-dimensional maps and blood gas analysis

Summary The effects of smoking on mental function were investigated by the two-dimensional EEG mapping method, and the results were analyzed in conjunction with blood gas data that had been obtained simultaneously. Healthy medical students from the National Defense Medical College were used as the subjects for this experiment. They live in the same dormitory and a similar lifestyle to regular military personnel. Tests were carried out on two successive days, and in between the two testing sessions, each subject was requested to refrain from smoking for 24 hours. During the testing sessions, EEGs were recorded with eyes closed, before and after smoking. Two-dimensional maps were generated by unbiased polynomial interpolation for alpha activity. Various blood chemical measurements were made, among which, partial pressure of carbon dioxide (pCO₂) and percentage of carbon monoxide hemoglobin (%COHb) were studied in relation to EEG changes. The smoking induced wide-spread amplitude decrease in the alpha maps. After 24 hours of withdrawal, alpha amplitude increased, although it decreased again when smoking resumed. Either the correlation between EEG amplitude and %COHb, or the correlation between EEG amplitude and pCO₂, was examined in three regions (anterior: A, middle: M and posterior: P) of the two-dimensional maps in both slow and quick smokers. There were no correlations observed between changes in the EEG amplitude and changes in %COHb induced by smoking, in any of the three regions in either fast or slow smokers. However, there was a clear correlation between changes in the EEG amplitude and changes in pCO₂ in quick smokers, the correlation coefficient being approximately -0.7. It is possible that this relationship was due to hyperventilation, since the same tendency was not observed in slow smokers.This work was supported by a grant from the Smoking Research Center.