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Abstract: Past near infrared spectroscopy (NIRS) studies have reported different changes in cytochrome C oxidase (Cyt) redox status during similar interventions that cause tissue ischaemia. We investigated whether there were distinctive differences when NIRS signals were obtained simultaneously from different tissues during total circulatory arrest. Forty-two healthy 10 kg commercial swine (Sus scrofa) on cardiopulmonary bypass, each underwent 2 to 8 sequential periods of hypothermic circulatory arrest for 7.5 min. Prior to each arrest, key physiologic variables were adjusted to 1 of 81 combinations of high, normal, or low levels of core temperature, hematocrit, pH, and serum glucose. Each combination was repeated at least twice. Simultaneous NIRS monitoring yielded 202 brain, 191 spine, and 199 muscle Cyt data sets, which were then classified into 13 distinctive patterns of change. The data sets always differed between tissues in the same arrest trial and subject. Typically, brain Cyt rapidly became more reduced at the start of arrest and changed little thereafter, muscle Cyt behaved comparably to brain Cyt but continued to become reduced throughout the arrest, and spine Cyt either did not change status or gradually became more reduced over the course of arrest. The spine pattern''s mean rate of change was 12 times slower than those of the brain or muscle. The Cyt patterns of change were classified into 13 groups which were significantly related to core temperature in the brain and spine, and hematocrit in muscle. The respiratory response in mitochondria during systemic circulatory arrest differs between brain, spine and muscle tissues in the same subject. [Copyright &y& Elsevier]

Purpose: Near infrared spectroscopy (NIRS) monitors absolute changes in concentration of chromophores from an unquantified baseline. A change in oxygenation is required to obtain information. Clinically, knowing initial chromophore concentration is desirable. We sought absolute initial concentrations by combining NIRS measurements with simultaneous Eppendorf histograph measurement (absolute values of tissue partial pressure of oxygen (pO [ABSTRACT FROM AUTHOR]

During cardiac surgery, bypass pumps rely on pressure monitors to evaluate flow. We studied whether it would be possible to optimize pump flow by monitoring changes in cerebral cytochrome a,a [ABSTRACT FROM AUTHOR]

Near infrared spectroscopy (NIRS) monitors changes in oxygenated haemoglobin (HbO [ABSTRACT FROM AUTHOR]

AbstractBackground: Since 1987 research articles have been catalogued with the author's affiliation address in the 40 databases of the Medical Literature Analysis and Retrieval System (MEDLARS) of the National Library of Medicine, Bethesda, Md. The present study was conducted to examine the Canadian entries in MEDLARS to interpret past and future trends and to combine the MEDLARS demographic data with data from other sources to rank Canadian research output of human studies both nationally and internationally.Methods: The PubMed Web site of the National Library of Medicine was used to count medical articles archived in MEDLARS and published from Jan. 1, 1989, through Dec. 31, 1998. The articles attributed to Canadian authors were compared by country, province, city, medical school, hospital, article type, journal and medical specialty.Results: During the study period Canadian authors contributed on average 3% (standard deviation [SD] 0.2%) of the worldwide MEDLARS content each year, which translated to a mean of 11 067 (SD 1037) articles per year; 49% were human studies, of which 13% were clinical or controlled trials, and 55% involved people aged 18 years or less. In total, 68% of the articles were by authors affiliated with Canadian medical schools; those affiliated with the University of Toronto accounted for the greatest number (8604), whereas authors affiliated with McGill University had the greatest rate of annual increase in the quantity published (8%). Over one-third (38%) of the articles appeared in Canadian journals. When counted by specialty, 17% of the articles were by authors with clinical specialties, 5% by those with surgical specialties and 3% by those with laboratory specialties.Interpretation: The annual rate of increase in research output for Canada was more than 3 times higher than that seen world wide. Canada is now ranked seventh among countries contributing human studies to MEDLARS. The increase indicates that Canada's medical schools are... [ABSTRACT FROM AUTHOR]

Objective: To determine the accuracy and feasibility of a monitoring tool completed by parents for screening at-risk and community infants and children for developmental problems. Methods: We assessed 43 children following open-heart surgery and 68 community children (aged 4-36 mo) at prescribed intervals using the Ages and Stages Questionnaires (ASQ). Subjects were followed 3 years later (at age 5-6 yr) via telephone interview with their parents concerning developmental delay identified by physicians. Responses were confirmed by telephone interviews with family physicians. We then compared the results of the ASQ with the physician assessments. Results: Nine at-risk and 9 community children were lost to follow-up. The ASQ identified 4 of the 25 at-risk children as having developmental delay, while 2 of the 6 children assessed by a neurologist were identified as having developmental delay. The ASQ identified 2 of the 59 community children as having developmental delay, 1 of whom was assessed by a neurologist as having developmental delay. The ASQ had sensitivities of 75% in the at-risk group and 100% in the community group, and specificities of 95% and 90%, respectively. The parents were unanimous in their willingness to complete the assessments. Conclusion: The ASQ is feasible, inexpensive, easy to use, and was appreciated by the parents. It is a sufficiently sensitive and specific monitoring tool that its use in cardiac follow-up programs and in community programs for healthy children is warranted. Although this tool should not be used to replace clinical assessment, it can be used to rationalize access to specialist developmental assessment services. [ABSTRACT FROM AUTHOR]