Severe Hypercalcemia From Inhalation Pneumonitis via Activation of 1,25 Dihydroxyvitamin D.

Among the many causes of hypercalcemia are inflammatory conditions, particularly involving granulomatous disease. We present a case of a previously healthy woman who arrived at the emergency department with severe symptomatic hypercalcemia. Workup revealed elevated levels of 1,25-dihydroxyvitamin D along with pneumonitis on computed tomography (CT) imaging. The patient revealed frequent use of eucalyptus oil in her home essential oil diffuser and after removal of the offending agent her hypercalcemia, elevated 1,25-dihydroxyvitamin D, and pneumonitis on CT imaging all resolved.

Venovenous perfusion-induced systemic hyperthermia: five-day sheep survival studies.

OBJECTIVE: Since hyperthermia selectively kills lung cancer cells, we developed a venovenous perfusion-induced systemic hyperthermia system for advanced lung cancer therapy. Our objective was to test the safety and accuracy of our venovenous perfusion-induced systemic hyperthermia system in 5-day sheep survival studies, following Good Laboratory Practice standards. METHODS: Our venovenous perfusion-induced systemic hyperthermia system, which included a double-lumen cannula (Avalon Elite, Rancho Dominguez, Calif), a centrifugal pump (Bio-Pump 560; Medtronic Inc, Minneapolis, Minn), a heat exchanger (BIOtherm; Medtronic Perfusion Systems, Brooklyn Park, Minn), and a heater/cooler (modified Blanketrol IIIl Cincinnati Subzero, Cincinnati, Ohio), was tested in healthy adult sheep (n=5). The perfusion circuit was primed with prewarmed Plasma-Lyte A (Baxter Healthcare Corp, Deerfield, Ill) and de-aired. Calibrated temperature probes were placed in the right and left sides of the nasopharynx, bladder, and blood in/out tubing in the animal. The double-lumen cannula was inserted through the jugular vein into the superior vena cava, with the tip in the inferior vena cava. RESULTS: Therapeutic core temperature (42°C-42.5°C), calculated from the right and left sides of the nasopharynx and bladder temperatures, was achieved in all sheep. Heating time was 21±5 minutes. Therapeutic core temperature was maintained for 120 minutes followed by a cooling phase (35±6 minutes) to reach baseline temperature. All sheep recovered from anesthesia with spontaneous breathing within 4 hours. Arterial, pulmonary, and central venous pressures were stable. Transient increases in heart rate, cardiac output, and blood glucose occurred during hyperthermia but returned to normal range after venovenous perfusion-induced systemic hyperthermia termination. Electrolytes, complete blood counts, and metabolism enzymes were within normal to near normal range throughout the study. No significant venovenous perfusion-induced systemic hyperthermia-related hemolysis was observed. Neurologic assessment showed normal brain function all 5 days. CONCLUSIONS: Our venovenous perfusion-induced systemic hyperthermia system safely delivered the hyperthermia dose with no significant hyperthermia-related complications.

Biplane angiography for experimental validation of computational fluid dynamic models of blood flow in artificial lungs.

This article presents an investigation into the validation of velocity fields obtained from computational fluid dynamic (CFD) models of flow through the membrane oxygenators using x-ray digital subtraction angiography (DSA). Computational fluid dynamic is a useful tool in characterizing artificial lung devices, but numerical results must be experimentally validated. We used DSA to visualize flow through a membrane oxygenator at 2 L/min using 37% glycerin at 22°C. A Siemens Artis Zee system acquired biplane x-ray images at 7.5 frames per second, after infusion of an iodinated contrast agent at a rate of 33 ml/s. A maximum cross-correlation (MCC) method was used to track the contrast perfusion through the fiber bundle. For the CFD simulations, the fiber bundle was treated as a single momentum sink according to the Ergun equation. Blood was modeled as a Newtonian fluid, with constant viscosity (3.3 cP) and density (1050 kg/m3). Although CFD results and experimental pressure measurements were in general agreement, the simulated 2 L/min perfusion did not reproduce the flow behavior seen in vitro. Simulated velocities in the fiber bundle were on average 42% lower than experimental values. These results indicate that it is insufficient to use only pressure measurements for validation of the flow field because pressure-validated CFD results can still significantly miscalculate the physical velocity field. We have shown that a clinical x-ray modality, together with a MCC tracking algorithm, can provide a nondestructive technique for acquiring experimental data useful for validation of the velocity field inside membrane oxygenators.

Improved computational fluid dynamic simulations of blood flow in membrane oxygenators from X-ray imaging.

Computational fluid dynamics (CFD) is a useful tool in characterizing artificial lung designs by providing predictions of device performance through analyses of pressure distribution, perfusion dynamics, and gas transport properties. Validation of numerical results in membrane oxygenators has been predominantly based on experimental pressure measurements with little emphasis placed on confirmation of the velocity fields due to opacity of the fiber membrane and limitations of optical velocimetric methods. Biplane X-ray digital subtraction angiography was used to visualize flow of a blood analogue through a commercial membrane oxygenator at 1-4.5 L/min. Permeability and inertial coefficients of the Ergun equation were experimentally determined to be 180 and 2.4, respectively. Numerical simulations treating the fiber bundle as a single momentum sink according to the Ergun equation accurately predicted pressure losses across the fiber membrane, but significantly underestimated velocity magnitudes in the fiber bundle. A scaling constant was incorporated into the numerical porosity and reduced the average difference between experimental and numerical values in the porous media regions from 44 ± 4% to 6 ± 5%.