Journal of clinical monitoring and computing
-
J Clin Monit Comput · Apr 2017
Comparative StudyEstimated continuous cardiac output based on pulse wave transit time in off-pump coronary artery bypass grafting: a comparison with transpulmonary thermodilution.
To evaluate the accuracy of estimated continuous cardiac output (esCCO) based on pulse wave transit time in comparison with cardiac output (CO) assessed by transpulmonary thermodilution (TPTD) in off-pump coronary artery bypass grafting (OPCAB). We calibrated the esCCO system with non-invasive (Part 1) and invasive (Part 2) blood pressure and compared with TPTD measurements. We performed parallel measurements of CO with both techniques and assessed the accuracy and precision of individual CO values and agreement of trends of changes perioperatively (Part 1) and postoperatively (Part 2). ⋯ During OPCAB, esCCO demonstrated poor accuracy, precision and trending ability compared to TPTD. Postoperatively, non-invasive esCCO showed better agreement with TPTD. However, invasive calibration of esCCO did not improve the accuracy and precision and the trending ability of method.
-
J Clin Monit Comput · Apr 2017
Case ReportsFalsely low values of oxygen saturation measured by pulse oximetry in a boy treated with Chinese herb tea.
An 8-year-old boy suffering from progressive glioblastoma was scheduled for neurosurgery. Prior to induction of anaesthesia pulse oximetry measured 64 % saturation of oxygen (SpO2). Arterial blood gas analysis revealed normal oxygen saturation and normal oxygen partial pressure. ⋯ Blood samples were taken and analysed. Absorption spectroscopy from the patient's blood showed an uncommon absorption maximum at 684 nm besides the normal maxima. The normalisation of SpO2 values after stopping Chinese herb tea administration leads to the conclusion that one of its ingredients caused the distorted pulse oximetry measurement.
-
J Clin Monit Comput · Apr 2017
Positive and negative staircase effect during single twitch and train-of-four stimulation: a laboratory study in dogs.
A positive staircase effect is well documented during neuromuscular monitoring. However, the increase in twitch amplitude may not remain stable over time. We compared the staircase phenomenon and twitch stability during single twitch (ST) or train-of-four (TOF) stimulation in anesthetized dogs. ⋯ An initial increase in ST amplitude remained stable over the observation period, but the increase in T1 amplitude during TOF was frequently followed by a decay. A stable twitch amplitude (variation <5 % in 5 min) was observed in all dogs with ST after 15 min of stimulation, which was not the case during TOF stimulation. Therefore, it appears at least in dogs, that ST might offer some advantages over T1 for measuring twitch amplitude.
-
J Clin Monit Comput · Apr 2017
The effects of ventricular drainage on the intracranial pressure signal and the pressure reactivity index.
In subarachnoid hemorrhage (SAH) patients intracranial pressure (ICP) is usually monitored via an extraventricular drain (EVD), which can produce false readings when the drain is open. It is established that both the ICP cardiac pulse frequency and long term trends over several hours are often seriously corrupted. The aim of this study was to establish whether or not the intermediate frequency bands [respiratory, Mayer wave and very low frequency (VLF)] were also corrupted. ⋯ We found a small but statistically significant decrease during open-drain periods. Based on analysis of the change in the PRx distribution during open drainage we concluded that this decrease also represented physiological changes rather than artifact. In summary the ICP respiratory, Mayer wave, and VLF frequency bands are not corrupted when the EVD is open, and it safe to use these for autoregulation studies.