Toyoki Kugimiya

Changes in cerebral blood flow estimated after stellate ganglion block by single photon emission computed tomography

The validity of the hypothesis that the cerebral vasculature is under the control of sympathetic innervation was investigated using brain scintigraphy imaging before and after stellate ganglion block (SGB). The experiment with HM-PAO showed a definite increase in the blood flow of the brain on the block side on both by the dynamic images and the SPECT images. The tympanic temperature (Tty) of the block side decreased significantly after SGB, compared to the unblock side in this study, as had been reported before. This change in Tty coinsided with the increase in cerebral blood flow as mentioned above. This study demonstrated that the cerebral vasculature is under the control of sympathetic innervation, the pathway of which is relayed and/or passes through the stellate ganglion. We conclude that SGB increases intracerebral blood flow and can also exert secondary effects systemically due to CNS blood flow changes as have been previously reported.

Laboratory evaluation of heat-and-moisture exchangers.

We conducted a laboratory study on six commercially available heat and moisture exchangers in order to determine and compare their water retaining efficiency and their contribution to airway resistance. The Gambro-Engstrom Edith Flex device was the most desirable of the six devices we evaluated in terms of its water retaining efficiency. The NMI Pneumoist 1 and the Siemens Servo Humidifier 153 units had good water retaining capacity but their higher airflow resistance need close monitoring, especially after prolonged clinical use. The Pall HME 15–22 and the Portex Humid-Vent 1 devices were also efficient in water retaining capacity. The Pall also demonstrated low airflow resistance and the minimum increase in airflow resistance after water immersion. The pathogen filtering capacity of the Pall should also be considered an additional advantage, especially in infected patients. The Terumo Breathaid device performed worst of all six devices, but it was still better than no HME at all.

A Systm of Computer Integration of Patient Monitors in Operating Rooms

As one of the major subsystems of our new THE OPERATION SUPPORTING INFORMATION SYSTEM IN THE SURGICAL CENTER, we have developed a system which integrates patient monitors in operating rooms.

Dependency of O2-affinity effects on O2 consumption in the isolated rat heart.

We have studied the effect of a decrease in hemoglobin-O2 affinity (increased P50) on O2 delivery in the non-paced, isolated, blood-perfused rat heart before and after coronary vasodilatation with and without an increase in myocardial O2 consumption (MVO2) produced with isoproterenol. Changes in perfusate P50 were produced with orthoiodosodium benzoate (OISB). Low concentrations of isoproterenol (0.74 micrograms/liter) caused no significant changes in coronary blood flow (QCOR) or MVO2 per beat. Perfusion with OISB-treated (8 mM) blood increased P50 from 29 to 33 mmHg at constant pH. MVO2 per beat increased significantly, QCOR did not change, and the ratio QCOR/MVO2, a reflection of the flow/metabolism distribution, decreased to values obtained in the absence of isoproterenol. With high doses of isoproterenol (5.0 micrograms/liter), MVO2 per beat and QCOR/MVO2 increased. Addition of OISB (13 mM) increased P50 from 29 to 39 mmHg, with no significant reduction in either QCOR or the QCOR/MVO2 ratio. Our data suggest that a decrease in blood-O2 affinity affects myocardial O2 delivery depending on the initial metabolic requirement: at basal MVO2 changes in the distribution of myocardial blood flow are probably secondary to the effects of PO2 on vessels that supply metabolically less active regions; at high MVO2 and following a maximum increase in capillary density, changes in vascular PO2 appear less effective than locally generated metabolic vasodilators, and distribution of blood flow is unaffected.