Journal of clinical monitoring and computing
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J Clin Monit Comput · Feb 2017
Towards an optimal paradigm for intraoperative auditory nerve monitoring with auditory steady state responses.
Auditory steady state responses (ASSR) may offer an alternative to brainstem auditory evoked potentials for monitoring of the auditory nerve during surgical procedures. In the current study, we evaluated the influence of noise on ASSR characteristics in total intravenous anesthesia (TIVA). Simulated ASSR in real noise recorded during surgery under TIVA were constructed with known parameters. ⋯ Choice of parameters strongly influences detection and characteristics of ASSR. Optimal parameters enabled detection after 16 s in 45 %. Due to specific noise characteristics, modulation has a critical impact, which is currently not sufficiently recognized in ASSR studies.
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J Clin Monit Comput · Feb 2017
The relationship of the musculocutaneous nerve to the brachial plexus evaluated by MRI.
Axillary plexus blocks (AXB) are widely used for upper limb operations. It is recommend that AXB should be performed using a multiple injection technique. Information about the course and position of the musculocutaneous nerve (MCN) is of relevance for AXB performance. ⋯ In 37 patients the MCN exit point was positioned inside the Q1 quadrant (lateral anterior to the axillary artery) and in 11 patients inside the Q2 quadrant (medial anterior to the axillary artery). There is a wide variability as to where the musculocutaneous nerve (MCN) leaves the axillary sheath. Therefore multiple injection techniques, or the use of a proximally directed catheter, should be appropriate to block the MCN.
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J Clin Monit Comput · Feb 2017
Heart period and blood pressure characteristics in splanchnic arterial occlusion shock-induced collapse.
The nature of hemodynamic instability typical of circulatory shock is not well understood, but an improved interpretation of its dynamic features could help in the management of critically ill patients. The objective of this work was to introduce new metrics for the analysis of arterial blood pressure (ABP) in order to characterize the risk of catastrophic outcome in splanchnic arterial occlusion (SAO) shock. Continuous ABP (fs = 1 kHz) was measured in rats during experimental SAO shock, which induced a fatal pressure drop (FPD) in ABP. ⋯ Baroreflex sensitivity (BRS) was assessed by means of a bivariate model. The approach to FPD of the animals who collapsed (FFPD) was characterized by higher BRS in the low frequency band versus SFPD animals (0.36 ± 0.15 vs. 0.19 ± 0.12 ms/mmHg, p value = 0.0196), bradycardia as indicated by the HPC (0.76 ± 0.57 vs. 1.94 ± 1.27, p value = 0.0179) and higher but unstable blood pressure as indicated by BPC (3.02 ± 2.87 vs. 1.47 ± 1.29, p value = 0.0773). The HPC and BPC indices demonstrated promise as potential clinical markers of hemodynamic instability and impending cardiovascular collapse, and this animal study suggests their test in data from intensive care patients.