Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2015
Cutaneous mitochondrial respirometry: non-invasive monitoring of mitochondrial function.
The recently developed technique for measuring cutaneous mitochondrial oxygen tension (mitoPO2) by means of the Protoporphyrin IX-Triplet State Lifetime Technique (PpIX-TSLT) provides new opportunities for assessing mitochondrial function in vivo. The aims of this work were to study whether cutaneous mitochondrial measurements reflect mitochondrial status in other parts of the body and to demonstrate the feasibility of the technique for potential clinical use. The first part of this paper demonstrates a correlation between alterations in mitochondrial parameters in skin and other tissues during endotoxemia. ⋯ A first prototype of a clinical PpIX-TSLT monitor is described and its usability is demonstrated on human skin. We expect that clinical implementation of this device will greatly contribute to our understanding of mitochondrial oxygenation and oxygen metabolism in perioperative medicine and in critical illness. Our ultimate goal is to develop a clinical monitor for mitochondrial function and the current results are an important step forward.
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J Clin Monit Comput · Aug 2015
Randomized Controlled TrialTranscutaneous continuous carbon dioxide tension monitoring reduced incidence, degree and duration of hypercapnia during combined regional anaesthesia and monitored anaesthesia care in shoulder surgery patients.
We studied the impact of transcutaneous continuous carbon dioxide tension (PtcCO2) monitoring on ventilation and oxygenation during monitored anaesthesia care (MAC) in patients scheduled for shoulder surgery with continuous interscalene block. 50 patients were randomised either to the intervention (I-group) or the control (C-group) group. In both groups MAC was performed using target controlled infusion of propofol and remifentanil. MAC regimen was adapted to PtcCO2 values in the I-group, whereas the C-group was blinded for these values. ⋯ Sensitivity and specificity of PtcCO2 to detect changes of PaCO2 was 0.94 and 0.56, respectively. In no patient SpO2 or SaO2 values lower than 90% were measured. Despite a moderate agreement between PaCO2 and PtcCO2 the PtcCO2 monitoring significantly reduced incidence, degree and duration of hypercapnia in shoulder surgery patients with MAC.
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J Clin Monit Comput · Aug 2015
Effect of concurrent oxygen therapy on accuracy of forecasting imminent postoperative desaturation.
Episodic postoperative desaturation occurs predominantly from respiratory depression or airway obstruction. Monitor display of desaturation is typically delayed by over 30 s after these dynamic inciting events, due to perfusion delays, signal capture and averaging. Prediction of imminent critical desaturation could aid development of dynamic high-fidelity response systems that reduce or prevent the inciting event from occurring. ⋯ In conclusion, we report the use of autoregressive models to predict [Formula: see text] and forecast imminent critical desaturation events in the postoperative period with high degree of accuracy. These models reliably predict critical desaturation in patients receiving supplemental oxygen therapy. While high-fidelity prophylactic interventions that could modify these inciting events are in development, our current study offers proof of concept that the afferent limb of such a system can be modeled with a high degree of accuracy.
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J Clin Monit Comput · Aug 2015
The accuracy of respiratory rate assessment by doctors in a London teaching hospital: a cross-sectional study.
Respiratory rate (RR) is one of the most sensitive markers of a patient condition and a core aspect of multiple clinical assessment tools. Doctors use a number of methods to assess RR, including formal measurement, and 'spot' assessments, although this is not recommended. This study aimed to assess the accuracy of the methods of RR measurement being used by doctors. ⋯ We observed a trend towards decreasing accuracy of 'spot' assessments with increasing clinical experience (p = 0.0490). Current methods of RR assessment by doctors are inaccurate. This may be significantly delaying appropriate clinical care, or even misguiding treatment.
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J Clin Monit Comput · Aug 2015
Comprehensive diagnosis of whole-body acid-base and fluid-electrolyte disorders using a mathematical model and whole-body base excess.
A mathematical model of whole-body acid-base and fluid-electrolyte balance was used to provide information leading to the diagnosis and fluid-therapy treatment in patients with complex acid-base disorders. Given a set of measured laboratory-chemistry values for a patient, a model of their unique, whole-body chemistry was created. This model predicted deficits or excesses in the masses of Na(+), K(+), Cl(-) and H2O as well as the plasma concentration of unknown or unmeasured species, such as ketoacids, in diabetes mellitus. ⋯ The results of this study showed the importance of a complete set of laboratory measurements to obtain sufficient accuracy of the quantitative diagnosis; having only a minimal set, just pH and PCO2, led to a large scatter in the predicted results. A computer module was created that would allow a clinician to achieve this diagnosis at the bedside. This new diagnostic approach should prove to be valuable in the treatment of the critically ill.