Anesthesiology
-
Previous experimental studies of ventilator-induced lung injury have shown that positive end-expiratory pressure (PEEP) is protective. The authors hypothesized that the application of PEEP during volume-controlled ventilation with a moderately high tidal volume (VT) in previously healthy in vivo rats does not attenuate ventilator-induced lung injury if the peak airway pressure markedly increases during the application of PEEP. ⋯ In contrast to previous reports, PEEP exacerbated lung damage and contributed to fatal outcome in an in vivo, mild overdistension model of ventilator-induced lung injury in previously healthy rats. That is, the addition of high PEEP to a constant large VT causes injury in previously healthy animals.
-
Anesthetics depress both ventilatory and upper airway dilator muscle activity and thus put the upper airway at risk for collapse. However, these effects are agent-dependent and may involve upper airway and diaphragm muscles to varying degrees. The authors assessed the effects of pentobarbital on upper airway dilator and respiratory pump muscle function in rats and compared these results with the effects of normal sleep. ⋯ Pentobarbital in rats impairs respiratory genioglossus activity compared to the awake state, but the decrease is no greater than seen during natural sleep. During anesthesia, in the absence of pharyngeal airflow, phasic genioglossus activity is increased in a dose-dependent fashion.
-
When a recovery room is fully occupied, patients frequently wait in the operating room after emerging from anesthesia. The frequency and duration of such delays depend on operating room case volume, average recovery time, and recovery room capacity. ⋯ A key managerial insight is that there is a sensitive relationship among caseload and number of recovery beds and the magnitude of recovery congestion. This is typical in highly utilized systems. The queueing approach is useful because it enables the investigation of future scenarios for which historical data are not directly applicable.
-
Development of coagulopathy is a serious complication arising from isolated traumatic brain injury, and it predicts poor outcome. The underlying mechanism has not yet been established, although coagulopathy arising from brain tissue injury and the release of tissue factor may represent the pathophysiology. The authors investigated dynamic whole-blood clot formation (ROTEM) in a recently developed porcine model of induced severe intracranial hypertension. ⋯ In a porcine model, induction of increased intracranial pressure causing severe intracranial hypertension was associated with a pronounced activation of the coagulation system. Taken together, the various results indicate that tissue factor probably represents the main trigger of hypercoagulopathy found in these pigs.
-
Preconditioning the brain with volatile anesthetics seems to be a viable option for reducing ischemic cerebral injury. However, it is uncertain whether this preconditioning effect extends over a longer period of time. The purpose of this study was to determine if sevoflurane preconditioning offers durable neuroprotection against cerebral ischemia. ⋯ In this model of transient focal cerebral ischemia, sevoflurane preconditioning induced effective but transient neuroprotective effects. Sevoflurane preconditioning also decreased ischemia-induced apoptosis in a more sustained way because it was observed up to 7 days after injury.