Clinical physiology and functional imaging
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Clin Physiol Funct Imaging · Jul 2018
Effect of spontaneous saliva swallowing on short-term heart rate variability (HRV) and reliability of HRV analysis.
The effects of effortful swallowing and solid meal ingestions on heart rate variability (HRV) have been examined previously. The effects of spontaneous saliva swallowing on short-term HRV and reliability of HRV analysis have not been studied before. The effect of saliva swallowing on HRV analyses parameters [meanRRI, SDNN (standard deviation of normal-to-normal), LF (low frequency), HF (high frequency) powers, LH/HF] and the reliability of LF and HF powers were investigated by frequency, time-frequency and intraclass correlation coefficient (ICC) analyses. ⋯ When the analyses were made for 2-min signal periods, these values decreased to 0·63 and 0·67. We concluded that spontaneous saliva swallowing can change HRV parameters. We have also seen that changes in swallowing rate and use of short signal segments may reduce the reliability of HRV analyses.
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Clin Physiol Funct Imaging · May 2018
Comparative Study Observational StudyComparison of cardiac output estimates by bioreactance and inert gas rebreathing methods during cardiopulmonary exercise testing.
This study assessed the agreement between cardiac output estimated by inert gas rebreathing and bioreactance methods at rest and during exercise. ⋯ Bioreactance and inert gas rebreathing methods show acceptable levels of agreement for estimating cardiac output at higher levels of metabolic demand. However, they cannot be used interchangeably due to strong disparity in results at rest and low-to-moderate exercise intensity.
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Clin Physiol Funct Imaging · Mar 2018
Comparative StudyDiscriminatory ability of right atrial volumes with two- and three-dimensional echocardiography to detect elevated right atrial pressure in pulmonary hypertension.
Pulmonary hypertension (PH) patients have high mortality due to right ventricular failure. Predictors of poor prognostic outcome are increased right atrial volume (RAV) and elevated mean right atrial pressure (mRAP). Our aim was to determine whether RAV measured with 2D echocardiography (2DE) and 3D echocardiography (3DE) can detect elevated mRAP in patients evaluated for PH. ⋯ Enlarged RA measures with 2DE and 3DE have better discriminatory ability compared with IVC measures, to detect elevated mRAP in patients evaluated for PH.
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Clin Physiol Funct Imaging · Mar 2018
Oesophageal Doppler guided optimization of cardiac output does not increase visceral microvascular blood flow in healthy volunteers.
Oesophageal Doppler monitoring (ODM) is used clinically to optimize cardiac output (CO) and guide fluid therapy. Despite limited experimental evidence, it is assumed that increasing CO increases visceral microvascular blood flow (MBF). We used contrast-enhanced ultrasound (CEUS) to assess whether ODM-guided optimization of CO altered MBF. ⋯ ODM-optimized CO reduces time to renal perfusion but does not alter renal or hepatic MBF. A lack of relationship between microvascular visceral perfusion and CO following ODM-guided optimization may explain the absence of improved clinical outcome with ODM monitoring.
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Clin Physiol Funct Imaging · Jan 2018
A spiky pattern in the course of electrical thoracic impedance as a very early sign of a developing pneumothorax.
A pneumothorax (PTX) is a potentially lethal condition in high-risk intensive care patients. Electrical impedance tomography (EIT) has been proven to detect PTX at the bedside. A so far not described pattern in the course of thoracic impedance at an early state of PTX was observed in a pig model of ventilator-induced lung injury (VILI) used for a more extensive study. ⋯ After application of VILI ventilation (38 ml kg-1 ), a PTX developed slowly, being confirmed by a continuous increase in the end-expiratory level on the right side and diverging levels of +0·320 ± 0·057 (right) and -0·193 ± 0·147 (left) at full manifestation. We assume that spikes reflect a temporary change in the electrical pathway caused by leakage into the pleural cavity. This newly described phenomenon of spikes is considered to be a potentially useful indicator for a very early detection of an evolving PTX in high-risk ICU patients.