Anesthesiology
-
Observational Study
The effect of extracerebral contamination on near infrared spectroscopy as revealed during organ donation: A prospective observational study in brain dead organ donors.
Near-infrared spectroscopy (NIRS) has been utilized widely in anesthesia and intensive care to monitor regional cerebral oxygen saturation (rScO2). A normal oxygenation of extracerebral tissues may overlay and thereby mask cerebral desaturations, a phenomenon known as extracerebral contamination. The authors investigated the effect of a cessation of extracerebral tissue perfusion on rScO2 in patients with anoxic brains. ⋯ The abrupt end of extracerebral contamination, caused by aortic clamping, affected both NIRS monitors to a considerable extent. Both the INVOS and the ForeSight monitor were unable to detect severe cerebral hypoxia or anoxia under conditions of normal extracerebral oxygenation. While both NIRS monitors may guide measures to optimize arterial oxygen supply to the head, they should not be used with the intention to detect isolated cerebral desaturations.
-
The efficiency of descending pain modulation, commonly assessed with the conditioned pain modulation procedure, is diminished in patients with chronic pain. The authors hypothesized that the efficiency of pain modulation is controlled by cortical opioid circuits. ⋯ Anterior cingulate cortex κ opioid receptor activation therefore diminishes descending control of nociception both in naive animals and as an adaptive response to chronic pain, likely by enhancing net descending facilitation. Descending control of nociception can be restored by activation of μ opioid receptors in the anterior cingulate cortex, but also by κ opioid receptor antagonists, providing a nonaddictive alternative to opioid analgesics. Navacaprant is now in advanced clinical trials.
-
In 1978, Dr. Pinsky's scientific career became firmly directed toward understanding the deeper meaning of heart-lung interactions. This would define his focus for the next 45 yr. ⋯ This fundamental observation was followed by many additional observations in both highly invasive animal studies supported by less invasive clinical studies, which showed that intrathoracic pressure-induced changes in the gradients for venous return to the heart and left ventricular ejection from the heart disproportionately affected both right ventricular and left ventricular function. The direct clinical implications of these results form the rationale for use of continuous positive airway pressure as a primary treatment of acute cardiogenic pulmonary edema and immediate endotracheal intubation for acute upper airway obstruction. These findings subsequently led to the practical use of dynamic changes in left ventricular stroke volume and the associated arterial pulse pressure during positive-pressure ventilation to identify volume responsiveness and, thus, to personalize resuscitation efforts in the treatment of acute cardiovascular insufficiency.