Journal of clinical monitoring and computing
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J Clin Monit Comput · Feb 2015
Analysis of heart rate variability during auditory stimulation periods in patients with schizophrenia.
The vulnerability-stress model is a hypothesis for symptom development in schizophrenia patients who are generally characterized by cardiac autonomic dysfunction. Therefore, measures of heart rate variability (HRV) have been widely used in schizophrenics for assessing altered cardiac autonomic regulations. The goal of this study was to analyze HRV of schizophrenia patients and healthy control subjects with exposure to auditory stimuli. ⋯ In comparison with control subjects, patients with schizophrenia exhibited lower high-frequency power and a higher low-frequency to high-frequency ratio. Moreover, while WN stimulus decreased parasympathetic activity in healthy subjects, no significant changes in heart rate and frequency-domain HRV parameters were observed between the auditory stimulation and rest periods in schizophrenia patients. We can conclude that HRV can be used as a sensitive index of emotion-related sympathetic activity in schizophrenia patients.
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J Clin Monit Comput · Feb 2015
Capability of a neck worn device to measure sleep/wake, airway position, and differentiate benign snoring from obstructive sleep apnea.
To evaluate the accuracy of a neck-worn device in measuring sleep/wake, detecting supine airway position, and using loud snoring to screen for obstructive sleep apnea. Study A included 20 subjects who wore the neck-device during polysomnography (PSG), with 31 records obtained from diagnostic and split-night studies. Study B included 24 community-based snorers studied in-home for up to three-nights with obstructive sleep apnea (OSA) severity measured with a validated Level III recorder. ⋯ Neck actigraphy appears capable of estimating sleep/wake. The accuracy of supine airway detection with the neck-device warrants further investigation. Measurement of loud snoring appears to provide a screening tool for differentiating positional apneic and benign snorers.
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J Clin Monit Comput · Feb 2015
Observational StudyThe relative trending accuracy of noninvasive continuous hemoglobin monitoring during hemodialysis in critically ill patients.
The pulse CO-Oximeter (Radical-7; Masimo Corp., Irvine, CA) is a multi-wavelength spectrophotometric method for noninvasive continuous monitoring of hemoglobin (SpHb). Because evaluating the relative change in blood volume (ΔBV) is crucial to avoid hypovolemia and hypotension during hemodialysis, it would be of great clinical benefit if ΔBV could be estimated by measurement of SpHb during hemodialysis. The capability of the pulse CO-Oximeter to monitor ΔBV depends on the relative trending accuracy of SpHb. ⋯ Bland-Altman analysis also revealed good agreement between ΔBV(SpHb) and ΔBV(CL-Hct) (bias, -0.77%; precision, 3.41%). Polar plot analysis revealed good relative trending accuracy of SpHb with an angular bias of 4.1° and radial limits of agreement of 24.4° (upper) and -16.2° (lower). The results of the current study indicate that SpHb measurement with the pulse CO-Oximeter has good relative trending accuracy.
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J Clin Monit Comput · Feb 2015
Pleth variability index-directed fluid management in abdominal surgery under combined general and epidural anesthesia.
Pleth variability index (PVI), a noninvasive dynamic indicator of fluid responsiveness has been demonstrated to be useful in the management of the patients with goal directed fluid therapy under general anesthesia, but whether PVI can be used to optimize fluid management under combined general and epidural anesthesia (GEN-EPI) remains to be elucidated. The aim of our study was to explore the impact of PVI as a goal-directed fluid therapy parameter on the tissue perfusion for patients with GEN-EPI. Thirty ASA I-II patients scheduled for major abdominal surgeries under GEN-EPI were randomized into PVI-directed fluid management group (PVI group) and non PVI-directed fluid management group (control group). 2 mL/kg/h crystalloid fluid infusion was maintained in PVI group, once PVI>13%, a 250 mL colloid or crystalloid was rapidly infused. 4-8 mL/kg/h crystalloid fluid infusion was maintained in control group, and quick fluid infusion was initiated if mean arterial blood pressure (BP)<65 mmHg. ⋯ The total amount of intraoperative fluids, the amount of crystalloid fluid and the first hour blood lactate levels during surgery were significantly lower in PVI than control group, P<0.05. PVI-based goal-directed fluid management can reduce the intraoperative fluid amount and blood lactate levels in patients under GEN-EPI, especially the crystalloid. Furthermore, the first hour following GEN-EPI might be the critical period for anesthesiologist to optimize the fluid management.
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J Clin Monit Comput · Feb 2015
Fluid responsiveness is about stroke volume, and not pulse pressure Yogi: the power of Doppler fluid management and cardiovascular monitoring.
Fluid infusion is one of the most common critical care interventions, yet approximately 50% of all fluid interventions are unnecessary and potentially harmful. An improved approach to identification of fluid responsiveness is of clinical importance. Currently fluid responsiveness is most frequently identified by blood pressure (BP) measurements or a surrogate. ⋯ This letter reminds clinicians of the physiologic limitations of PPV as a measure of fluid responsiveness, even when combined with physiologic challenges, and recommends the replacement of BP with SV measurements. The combination of accurate Doppler measurement of SV and physiologic challenges, as Dr Pinsky recommends, is a physiologically rational and effective approach to identification of fluid responsiveness with established evidence. The direct monitoring of SV and SV changes has the potential to improve a long standing critical care and anaesthetic conundrum; when to give fluid and when to stop.