Journal of clinical monitoring and computing
-
J Clin Monit Comput · Oct 2017
A delayed functional observer/predictor with bounded-error for depth of hypnosis monitoring.
With the motivation of providing safety for a patient under anesthesia, this paper suggests conditions for evaluating the correctness of an available user interface for systems under shared control based on observability and predictability requirements. Situation awareness is necessary for the user to make correct decisions about the inputs. In this article, we develop a technique to investigate the conditions under which an anesthetists can attain situation awareness about a limited but important aspect of anesthesia, namely depth of hypnosis (DOH). ⋯ Hence, attaining situation awareness about DOH is modeled as a bounded-error delayed functional observation/prediction. Unless such an observer/predictor exists for a system with a given user-interface, the safety of the operation may be compromised. The suggested technique proves that, in order to provide safety for the patient under anesthesia, it is necessary for the anesthetist to have access to the predictive information from a clinical decision support system.
-
J Clin Monit Comput · Oct 2017
Implementation of a novel postoperative monitoring system using automated Modified Early Warning Scores (MEWS) incorporating end-tidal capnography.
Modified Early Warning Scores (MEWS) provide real-time vital sign (VS) trending and reduce ICU admissions in post-operative patients. These early warning calculations classically incorporate oxygen saturation, heart rate, respiratory rate, systolic blood pressure, and temperature but have not previously included end-tidal CO2 (EtCO2), more recently identified as an independent predictor of critical illness. These systems may be subject to failure when physiologic data is incorrectly measured, leading to false alarms and increased workload. ⋯ Further study is needed to evaluate its clinical utility, including an end-tidal CO2 score, is feasibly implemented and can be useful in monitoring select post-operative patients for derangements in physiologic metrics. Like any other monitoring system, false alarms may occur at high rates. While further study is needed to determine the additive utility of EtCO2 in MEWS calculations, this study suggests utility of EtCO2 in select post-operative patients.
-
J Clin Monit Comput · Oct 2017
Identifying the position of the right atrium to align pressure transducer for CVP : Spirit level or 3D electromagnetic positioning?
The central venous pressure, CVP, is an important variable in the management of selected perioperative and intensive care cases and in clinical decision support systems, CDSS. In current routine, when measuring CVP the health care provider may use anatomical landmarks and a spirit level, SL, to adjust the pressure transducer to the level of the tricuspid valve, i.e. the phlebostatic axis. The aim of the study was to assess the agreement in the postoperative setting between the SL method and electromagnetic 3D positioning (EM). ⋯ The limits of agreement extended in excess of ±8 mmHg and half of the measurements had deviations outside an accepted error range of ±2.5 mmHg. There was a large variation in CVP measurements when assessing the agreement with the current method. This may indicate the need for improvement in accuracy, e.g. using the electromagnetic field positioning system, in association with routine monitoring and clinical decision support systems.
-
J Clin Monit Comput · Oct 2017
Intraoperative TTE inferior vena cava monitoring in elderly orthopaedic patients with cardiac disease and spinal-induced hypotension.
Objective To address the role of transthoracic echocardiography in inferior vena cava (IVC) monitoring in the management of haemodynamically unstable elderly patients subjected to lower limb orthopaedic surgery under spinal anesthesia. Possible implications in the postoperative care unit (PACU) length of stay (LOS) are investigated. Methods 41 elderly patients with cardiac diseases were recruited. ⋯ The primary risk factor for a prolonged stay in PACU, as determined by multiple regression analysis was RAP. Conclusions Patients with high dynamic collapsibility of the IVC may require aggressive treatment to restore their haemodynamic status. Additionally, intraoperative levels of RAP, as measured by IVCCI, can act as a predictor for increased LOS in the PACU.
-
J Clin Monit Comput · Oct 2017
Effective evaluation of arterial pulse waveform analysis by two-dimensional stroke volume variation-stroke volume index plots.
Arterial pulse waveform analysis (APWA) with a semi-invasive cardiac output monitoring device is popular in perioperative hemodynamic and fluid management. However, in APWA, evaluation of hemodynamic data is not well discussed. In this study, we analyzed how we visually interpret hemodynamic data, including stroke volume variation (SVV) and stroke volume (SV) derived from APWA. ⋯ The plots approximately shifted on the rectangular hyperbolic curves, depending on blood loss and blood transfusion. Arithmetic estimation is close to real measurement of the SVV-SV interaction in hyperbolic curves. In APWA, using SVV as an index of preload and the cardiac index or SVI derived from arterial pressure-based cardiac output as an index of cardiac function, is likely to be appropriate for categorizing hemodynamic stages as a substitute for Forrester subsets.