Journal of clinical monitoring and computing
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J Clin Monit Comput · Jun 2023
Feasibility and optimal choice of stimulation parameters for supramaximal stimulation of motor evoked potentials.
The aim was to investigate the feasibility and optimal stimulation parameters for supramaximal stimulation of muscle recorded transcranial electrical stimulation motor evoked potentials (mTc-MEP). ⋯ We recommend using setting 1 when monitoring mTc-MEPs with supramaximal stimulation, after which an individualized ISI optimization can be performed. Moreover, when using supramaximal stimulation, short ISI's (i.e. 1ms or 1.5ms) can be the optimal ISI for obtaining the highest mTc-MEP amplitude.
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J Clin Monit Comput · Jun 2023
Stomach, liver, kidney and skeletal muscle autoregulation evaluated by near-infrared spectroscopy in a swine model.
Different organs have different autoregulatory capacities for blood pressure changes and/or circulatory volume changes. This study assessed the autoregulation of the stomach, liver, kidney and skeletal muscle, under baseline, hypovolemic, and post-fluid-resuscitation conditions using near-infrared spectroscopy (NIRS). ⋯ In our NIRS-based assessment of autoregulatory capacity, the liver oxygenation is highly blood pressure dependent, and the kidney is highly susceptible and the skeletal muscle is highly tolerable to low blood pressure and volume loss.
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J Clin Monit Comput · Jun 2023
Observational StudyPreoperative assessment of optic nerve sheath diameter and heart rate variability to predict intraoperative brain condition in patients with supratentorial tumors: a prospective observational study.
Brain relaxation is an important requirement in intracranial neurosurgical procedures and optimal brain relaxation improves the operating conditions. Optic nerve sheath diameter (ONSD) is a non-invasive bedside surrogate marker of intracranial pressure (ICP) status. Elevated ICP is often associated with marked autonomic dysfunction. ⋯ A receiver operating curve was constructed to determine the cut off to predict intraoperative brain bulge. A CT grade more than 2, ONSD of greater than 0.63 cms and ratio of low frequency to high ratio (LF/HF) of more than 1.8 were good predictors of brain bulge. The changes in ONSD and HRV parameters, with the CT findings can be used as surrogate markers of increased ICP to help predict intraoperative brain condition.
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J Clin Monit Comput · Jun 2023
Oxygen saturation in intraosseous sternal blood measured by CO-oximetry and evaluated non-invasively during hypovolaemia and hypoxia - a porcine experimental study.
This study intended to determine, and non-invasively evaluate, sternal intraosseous oxygen saturation (SsO2) and study its variation during provoked hypoxia or hypovolaemia. Furthermore, the relation between SsO2 and arterial (SaO2) or mixed venous oxygen saturation (SvO2) was investigated. ⋯ Sternal blood has an oxygen saturation suggesting a mixture of venous and arterial blood. Changes in SsO2 relate well with changes in SvO2 during hypovolaemia or hypoxia. Further studies on the feasibility of using non-invasive measurement of changes in SsO2 to estimate changes in SvO2 are warranted.
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J Clin Monit Comput · Jun 2023
Increasing the reflection efficiency of the Sedaconda ACD-S by heating and cooling the anaesthetic reflector: a bench study using a test lung.
As volatile anaesthetic gases contribute to global warming, improving the efficiency of their delivery can reduce their environmental impact. This can be achieved by rebreathing from a circle system, but also by anaesthetic reflection with an open intensive care ventilator. We investigated whether the efficiency of such a reflection system could be increased by warming the reflector during inspiration and cooling it during expiration (thermocycling). ⋯ Thermocycling of the anaesthetic gas considerably increases the efficiency of the anaesthetic reflector and reduces anaesthetic consumption by almost half in a test lung model. Given that cooling can be miniaturized, this method carries a potential for further saving anaesthetics in clinical practice in the operating theatre as well as for inhaled sedation in the ICU.