Hormonal changes in brain dead patients.

Thirty neurologically impaired (Glasgow Coma Score less than 7) patients were evaluated to determine if changes in serum levels of thyroid hormone, cortisol, insulin, or lactate suggest that replacement therapy is needed before removal of organs for donation. Serum levels of free thyroxine (fT4), thyroid-stimulating hormone (TSH), reverse T3 (rT3), cortisol, insulin, and lactate were monitored in 16 patients before and after brain death and in 14 additional patients who were similarly compromised but did not become brain dead. Low fT3, normal fT4, and normal or high rT3 as found in most patients were consistent with a variant of the euthyroid sick syndrome although TSH was elevated in some patients. Cortisol, insulin, and lactate levels were also normal or high. No correlation was found between low thyroid hormones and elevated lactate or the amount of vasopressor needed to sustain BP. No significant changes occurred in hormone or lactate levels after brain death. The explanation for an elevated lactate remains unclear but we do not believe this single finding justifies the diagnosis of a hypothyroid state in these patients or the administration of thyroid hormone to brain dead organ donors.

Influence of recording scale on determination of left ventricular end-diastolic pressure.

Left ventricular (LV) pressure waveforms for 20 beats, originally recorded at 200 scale (200 torr/10 cm) were rescaled by a computer system to represent the identical beats recorded at 40 scale (40 torr/10 cm). Both the original and the rescaled beats were independently evaluated by eight cardiologists who were unaware of the nature of the manipulated data. For each beat the average left ventricular end-diastolic pressure (LVEDP) identified by the eight cardiologists was higher when analyzed on the 200 scale, with an average difference of 2.8 torr (P Less Than 0.001). This scale-dependence of pressure analysis has implications for the development of automated pressure analysis algorithms and for physician review of computer-determined LVEDP data points.