Clinical chemistry
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The status of conventional monitoring by vital signs and present concepts of invasive monitoring with the balloon-tipped pulmonary artery (Swan-Ganz) catheter are reviewed. Survivors of high-risk general surgery were observed to have cardiac index (CI) values averaging 4.5 L/min.m2, oxygen delivery (DO2) greater than 600 mL/min.m2, and oxygen consumption (VO2) greater than 170 mL/min.m2. By contrast, those who subsequently died during their hospitalization maintained relatively normal CI, DO2, and VO2 values. ⋯ Two-thirds recovered with increased cardiac function, more than one-half had improved perfusion, and paO2 increased in fewer than one-fifth of monitored events. These data provide an information base for criteria needed to develop therapeutic decision rules for noninvasive monitoring systems. When noninvasive data are continuously displayed early in the course of critical illness and high-risk conditions, therapy may be instituted early, while physiological deficits are still minimal and easily reversible.
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This short review will address the potential uses for quantitative analyses of organ function in the critically ill patient. Multiple system failure is common in the critical-care unit, and the ability to measure reserves of organ function may enable earlier detection and treatment of this problem and provide a more accurate prognosis for such patients.
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To test the relationship pK' = 6.103 + log[HCO3calc] - log[HCO3meas], we used a Corning 168 blood-gas analyzer to analyze 500 blood samples for pH and PCO2, from which we calculated a value for bicarbonate. We also analyzed 500 venous blood samples, collected simultaneously, for potentiometric total carbon dioxide with the Ektachem 700 analyzer. ⋯ The results also confirmed the positive bias caused by organic acids in the Ektachem method for total carbon dioxide. Analysis of the SMA 6/60 results indicated a significant decrease of the pK' in patients classified as having a metabolic acidosis.