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Biomedical subjects

B A Shapiro

Publications and source records attributed to B A Shapiro.

108 records · Page 6Linked to original sources
PubMed1980

The spectrophotometric absorbance of Intralipid.

The spectral absorbance of Intralipid, a phospholipid emulsion, was investigated to discern its effect, when parenterally administered, on the spectrophotometric measurement of hemoglobin (Hb), oxyhemoglobin (HbO2), and carboxyhemoglobin (HbCO). While accounting for dilutional factors, various concentrations of Intralipid in both water and hemoglobin solutions were analyzed at six wavelengths commonly used to measure Hb, HbO2 and HbCO. Absorbance increased linearly with Intralipid concentration at all wavelengths, and ranged from 0.034 at 505 nm to 0.019 at 626.6 nm per mg of Intralipid. Therefore, in patients receiving Intralipid, significant errors in Hb, HbO2 and HbCO measurements can be introduced if these measurements are made by oximetry, and the authors suggest that such measurements should be accomplished by methods other than spectrophotometry.

Absorption↗
PubMed1980

Adult respiratory distress syndrome after Placidyl abuse.

A case of intravenous Placidyl injection is described which resulted in pulmonary pathophysiology consistent with adult respiratory distress syndrome (ARDS). Concise documentation of pulmonary and hemodynamic function demonstrated the dramatic response to PEEP therapy. Previously reported cases, mechanisms, and similarity to heroin-induced ARDS are discussed.

Adult↗
PubMed1980

Minimizing errors in intrapulmonary shunt calculations.

In 100 critically ill patients, intrapulmonary shunts (Qsp/Qt) calculated by assuming a carboxyhemoglobin (HbCO) of zero and a hemoglobin saturation (HbO2) derived from the Severinghaus nomogram were compared to shunts calculated utilizing measured values of HbCO and HbO2. The differences were statistically significant (p less than 0.001). These 100 patients had a mean Hb of 11.9 g/dl and a mean HbCO of 1.7%. Measured shunt calculations in 30 critically patients were prospectively compared with shunt calculations utilizing the mean assumed values derived from the 100 patients initially studies. No statistically significant differences occurred between these two shunts. It is, therefore, concluded that errors attributable to the common practice of assuming zero HbCO and deriving HbO2 from nomograms will produce falsely high calculated intrapulmonary shunt values in critically ill patients. It is, therefore, important to measure accurately HbCO and HbO2 concentrations when monitoring intrapulmonary shunting in critically ill patients. However, if such measurements cannot be obtained, utilization of an assumed value of 1.5% for HbCO and HbO2 nomogram values will minimize errors in the shunt calculation.

Carbon Dioxide↗
PubMed1980

Changes in intrapulmonary shunting with administration of 100 percent oxygen.

The effects of increasing the fractional concentration of oxygen in the inspired gas to 1.0 on intrapulmonary shunting (Qsp) was evaluated in 82 intubated cardiovascularly stable patients in intensive care, regardless of airway pressure therapy or preexistent pulmonary pathologic abnormalities. Intrapulmonary shunting following administration of 100 percent oxygen increased in 132 of 140 measurements, decreased in seven, and remained unchanged in one measurement. The direction of change of Qsp with 100 percent oxygen shows no correlation with either airway pressure therapy or preexisting pulmonary disease.

Adult↗
PubMed1978

A stable blood product for pH-blood-gas quality control.

We describe how to prepare, store, and use a hemolyzed blood product for simultaneous pH, pCO2, and pO2 quality control. Tonometry of the blood product with two oxygen and two carbon dioxide concentrations resulted in consistent and reproducible values during 38 weeks. The resulting pH values were consistent and reproducible, demonstrating the metabolic acid-base stability of the blood product. We conclude that the proper preparation, storage, and use of the product results in consistent, reproducible, and economical quality control for pH, pCO2 and pO2 blood measurements.

Blood Chemical Analysis↗
PubMedDate not supplied

Reassessment of the assumed A-V oxygen content difference in the shunt calculation.

A study was undertaken in 15 patients to compare measured and assumed arteriovenous oxygen (A-V O2) content differences and their effects on resultant shunt calculations. All patients were on volume ventilators and demonstrated a stable cardiovascular state. Simultaneous measurements of the O2 content of a pulmonary artery (PA) and of a superior vena cava (SVC) sample were compared. A mean A-V 02 content difference of 3.5 plus or minus 0.8 volumes percent was obtained from the PA and 2.6 plus or minus 1.1 volumes percent from the SVC. The resultant shunt calculations derived from measured A-V 02 content differences were compared with the calculation based on an assumed A-V O2 content difference of 5 volumes percent. A method for extrapolating a "true" A-V 02 content difference from an SVC blood sample was obtained. The extrapolated value resulted in a more representative "true shunt" calculation in 13 of the 15 patients.

Aged↗