Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2011
Comparative StudyAn evaluation and comparison of intraventricular, intraparenchymal, and fluid-coupled techniques for intracranial pressure monitoring in patients with severe traumatic brain injury.
Intracranial pressure measurements have become one of the mainstays of traumatic brain injury management. Various technologies exist to monitor intracranial pressure from a variety of locations. Transducers are usually placed to assess pressure in the brain parenchyma and the intra-ventricular fluid, which are the two most widely accepted compartmental monitoring sites. The individual reliability and inter-reliability of these devices with and without cerebrospinal fluid diversion is not clear. The predictive capability of monitors in both of these sites to local, regional, and global changes also needs further clarification. The technique of monitoring intraventricular pressure with a fluid-coupled transducer system is also reviewed. There has been little investigation into the relationship among pressure measurements obtained from these two sources using these three techniques. ⋯ Intraparenchymal pressure monitoring provides equivalent, statistically similar pressure measurements when compared to intraventricular monitors in all care and clinical settings. This is particularly valuable when uninterrupted cerebrospinal fluid drainage is desirable.
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J Clin Monit Comput · Aug 2011
Comparative StudyInvestigation of photoplethysmographic signals and blood oxygen saturation values obtained from human splanchnic organs using a fiber optic sensor.
A reliable, continuous method of monitoring splanchnic organ oxygen saturation could allow for the early detection of malperfusion, and may prevent the onset of multiple organ failure. Current monitoring techniques have not been widely accepted in critical care monitoring. As a preliminary to developing a continuous indwelling device, this study evaluates a new handheld fiber optic photoplethysmographic (PPG) sensor for estimating the blood oxygen saturation (SpO(2)) of splanchnic organs during surgery. ⋯ The evaluation of a new fiber optic sensor on anaesthetized patients undergoing laparotomy demonstrated that good quality PPG signals and SpO(2) estimates can be obtained from splanchnic organs. Such a sensor may provide a useful tool for the intraoperative assessment of splanchnic perfusion.
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The pleth variability index (PVI), which is calculated from respiratory variations in the perfusion index (PI), reportedly predicts fluid responsiveness. However, vasomotor tone fluctuations induced by nociceptive stimuli change the PI and may reduce the accuracy of PVI. The aim of this study was to confirm the effects of surgical stimuli on PVI. ⋯ This study showed a significant increase in the PVI and a negative correlation between the changes in PVI and PI before and after the skin incision. The PVI can be calculated from the variations in the PI caused not by mechanical ventilation, but rather by fluctuations in vasomotor tone. When using the PVI as an indicator for fluid responsiveness, it is crucial to pay attention to fluctuations in vasomotor tone induced by nociceptive stimuli.
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J Clin Monit Comput · Aug 2011
The impact of induction of general anesthesia and a vascular occlusion test on tissue oxygen saturation derived parameters in high-risk surgical patients.
Tissue oxygen saturation (StO(2)) assessed using Near Infrared Spectroscopy and its derived parameters during a vascular occlusion test (VOT) can detect microvascular changes in septic shock patients. General anesthesia (GA) impacts microcirculation. Our aim was to study the effects of general anesthesia on StO(2) and StO(2) derived parameters obtained during VOT in patients referred for cardiac surgery. ⋯ StO(2) derived parameters during a VOT are impacted by GA induction. These parameters may have potential for microcirculation assessment in patients undergoing surgery.
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J Clin Monit Comput · Aug 2011
Cardioplegia and ventricular late potentials in cardiac surgical patients.
Ventricular late potentials (LP) recording with signal-averaged electrocar- diogram allow identifying patients at risk of sudden death and ventricular tachycardia. Cardiac surgery with cardiopulmonary bypass (CPB) could predispose to the development of myocardial ischemia related to imperfect cardioplegia. To the best of our knowledge, no study investigated the protection of cardioplegia and CPB regarding the occurrence of LP in patients without previous myocardial infarction and undergoing cardiac surgery. ⋯ The present study in cardiac surgical patients suggests that cardioplegia associated to CPB has no significant impact on the occurrence of LP, irrespective of surgery performed.