Journal of clinical monitoring and computing
-
During the wash-in period in low flow anaesthesia (LFA), high fresh gas flow is used to achieve the desired agent concentration. In this study, we aimed to evaluate the safety of fixed 1 L/min fresh gas flow desflurane anaesthesia in both the wash-in and maintenance periods in patients including the obese ones. 104 patients undergoing surgery under general anaesthesia were included. After endotracheal intubation, fresh gas flow was reduced to 1 L/min and the desflurane vaporizer was set at 18%. ⋯ The number of adjustments in vaporizer settings was 56. Average desflurane consumption was 0.33 ± 0.05 mL/min. We demonstrated that LFA without use of initial high fresh gas flow during the wash-in period is an effective, safe and economic method which is easy to perform.
-
J Clin Monit Comput · Feb 2019
Finger and forehead photoplethysmography-derived pulse-pressure variation and the benefits of baseline correction.
To non-invasively predict fluid responsiveness, respiration-induced pulse amplitude variation (PAV) in the photoplethysmographic (PPG) signal has been proposed as an alternative to pulse pressure variation (PPV) in the arterial blood pressure (ABP) signal. However, it is still unclear how the performance of the PPG-derived PAV is site-dependent during surgery. The aim of this study is to compare finger- and forehead-PPG derived PAV in their ability to approach the value and trend of ABP-derived PPV. ⋯ By correcting for the baseline variation, improved agreements were obtained for both the finger and forehead, and the difference between these two agreements was diminished. The tracking abilities for both finger- and forehead-derived PAV still warrant improvement for wide use in clinical practice. Overall, our results show that baseline-corrected finger- and forehead-derived PAV may provide a non-invasive alternative for PPV.
-
J Clin Monit Comput · Feb 2019
Observational StudyAn elevated respiratory quotient predicts complications after cardiac surgery under extracorporeal circulation: an observational pilot study.
Following cardiac surgery, hyperlactatemia due to anaerobic metabolism is associated with an increase in both morbidity and mortality. We previously found that an elevated respiratory quotient (RQ) predicts anaerobic metabolism. In the present study we aimed to demonstrate that it is also associated with poor outcome following cardiac surgery. ⋯ The AUC for RQ to predict mortality was 0.77 (IC95% [0.70-0.84]), with a threshold value of 0.76 (sensitivity 64%, specificity 100%). By comparison, the AUC for lactate levels was significantly superior (AUClact 0.89, IC95% [0.83-0.93], p = 0.02). In this study, elevated RQ appeared to be predictive of mortality after cardiac surgery with CPB.
-
J Clin Monit Comput · Feb 2019
Real-time, spectral analysis of the arterial pressure waveform using a wirelessly-connected, tablet computer: a pilot study.
Spectral analysis of the arterial pressure waveform, using specialized hardware, has been used for the retrospective calculation of the 'Spectral Peak Ratio' (SPeR) of the respiratory and cardiac arterial spectral peaks. The metric can quantify the cardiovascular response to volume loading by analysing the effect of changing tidal volume (indexed to body weight) (VTI) on pulse pressure variability. In this pilot study, the feasibility of real-time SPeR calculation, using a mobile computer which was wirelessly connected to the patient monitor, was evaluated by examining the determinants of SPeR in 60 cardiac-surgical patients. ⋯ Real-time spectral analysis of the arterial waveform was easily accomplished. The regression of SPeR on VTI was linear. β appeared to represent the slope of the cardiac response curve at the venous return curve equilibrium point. Measurements were possible at a significantly lower VTI than the equivalent time domain metrics.