Journal of clinical monitoring and computing
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J Clin Monit Comput · Oct 2007
Impact of withdrawal of 450 ml of blood on respiration-induced oscillations of the ear plethysmographic waveform.
It has been widely appreciated that ventilation-induced variations in systolic blood pressure during mechanical ventilation correlate with changes in intravascular volume. The present study assessed whether alterations in volume status likewise can be detected with noninvasive monitoring (ear plethysmograph) in non-intubated subjects (awake volunteers). ⋯ Respiration-induced changes of the ear plethysmographic waveform during spontaneous ventilation increase significantly as a consequence of withdrawal of approximately one unit of blood in healthy volunteers.
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J Clin Monit Comput · Oct 2007
Comparative StudyForehead reflectance oximetry: a clinical comparison with conventional digit sensors during laparotomic and laparoscopic abdominal surgery.
This study compared the performance of forehead reflectance and conventional pulse oximetry (SpO(2)) in mechanically ventilated, anesthetized patients undergoing major abdominal surgery with either laparoscopic or laparotomic techniques. ⋯ Forehead reflectance oximetry is as accurate as conventional digit based oximetry in mechanically ventilated patients undergoing laparotomic surgery in the supine position, but is significantly influenced by patient positioning and pneumoperitoneum during laparoscopic surgery.
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J Clin Monit Comput · Oct 2007
Autonomic activity during desflurane anesthesia in patients with brain tumors.
Although intracranial tumors may affect autonomic function, there are few reports of autonomic changes during anesthesia. The purpose of this study was to evaluate autonomic effects of anesthesia in patients with brain tumors compared to neurosurgical controls. ⋯ Tone-entropy analysis of heart rate indicates anesthetic related depression of autonomic activity with no difference between groups. Normal titration of desflurane concentrations to maintain adequate blood pressure produced desflurane requirements that were lower in patients with brain tumors, while autonomic and EEG activity were similar.
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J Clin Monit Comput · Oct 2007
Comparative StudyChange in pulse transit time and pre-ejection period during head-up tilt-induced progressive central hypovolaemia.
Traditional vital signs such as heart rate (HR) and blood pressure (BP) are often regarded as insensitive markers of mild to moderate blood loss. The present study investigated the feasibility of using pulse transit time (PTT) to track variations in pre-ejection period (PEP) during progressive central hypovolaemia induced by head-up tilt and evaluated the potential of PTT as an early non-invasive indicator of blood loss. ⋯ PTT may reflect variation in PEP and central blood volume, and is potentially useful for early detection of non-hypotensive progressive central hypovolaemia. Joint interpretation of PTT and RR trends or responses may help to characterize the extent of blood volume loss in critical care patients.
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J Clin Monit Comput · Oct 2007
Comparative StudyComparing Entropy and the Bispectral index with the Ramsay score in sedated ICU patients.
ENTROPY is a new anesthetic depth monitor based on the analysis of the EEG signal. Our aim has been to evaluate sedation of intubated surgical critically ill patients by means of the Ramsay sedation score, the Bispectral index and ENTROPY, and to analyse the correlation between these variables. ⋯ ENTROPY, BIS and Ramsay score values correlate significantly in sedated postoperative ICU patients. ENTROPY does not appear superior to BIS for the assessment of sedation in this context.