Journal of clinical monitoring and computing
-
J Clin Monit Comput · Jun 2016
Real time noninvasive estimation of work of breathing using facemask leak-corrected tidal volume during noninvasive pressure support: validation study.
We describe a real time, noninvasive method of estimating work of breathing (esophageal balloon not required) during noninvasive pressure support (PS) that uses an artificial neural network (ANN) combined with a leak correction (LC) algorithm, programmed to ignore asynchronous breaths, that corrects for differences in inhaled and exhaled tidal volume (VT) from facemask leaks (WOBANN,LC/min). Validation studies of WOBANN,LC/min were performed. Using a dedicated and popular noninvasive ventilation ventilator (V60, Philips), in vitro studies using PS (5 and 10 cm H2O) at various inspiratory flow rate demands were simulated with a lung model. ⋯ For the in vivo study, WOBANN,LC/min and WOBPHYS/min ranged from 3 to 12 J/min and there was an excellent relationship between WOBANN,LC/breath and WOBPHYS/breath, r = 0.93, r(2) = 0.86 (p < 0.01). An ANN combined with a facemask LC algorithm provides noninvasive and valid estimates of work of breathing during noninvasive PS. WOBANN,LC/min, automatically and continuously estimated, may be useful for assessing inspiratory muscle loads and guiding noninvasive PS settings as in a decision support system to appropriately unload inspiratory muscles.
-
J Clin Monit Comput · Jun 2016
Respiratory variations in the photoplethysmographic waveform amplitude depend on type of pulse oximetry device.
Respiratory variations in the photoplethysmographic waveform amplitude predict fluid responsiveness under certain conditions. Processing of the photoplethysmographic signal may vary between different devices, and may affect respiratory amplitude variations calculated by the standard formula. The aim of the present analysis was to explore agreement between respiratory amplitude variations calculated using photoplethysmographic waveforms available from two different pulse oximeters. ⋯ Concordance rate with a fluid load was 91 %. Agreement between respiratory variations in the photoplethysmographic waveform amplitude calculated from the available signals output by two different pulse oximeters was poor, both evaluated by LMSO and Bland-Altman plot. Respiratory amplitude variations from the available signals output by these two pulse oximeters are not interchangeable.
-
J Clin Monit Comput · Jun 2016
Clinical practice in perioperative monitoring in adult cardiac surgery: is there a standard of care? Results from an national survey.
This study was to investigate and define what is considered as a current clinical practice in hemodynamic monitoring and vasoactive medication use after cardiac surgery in Italy. A 33-item questionnaire was sent to all intensive care units (ICUs) admitting patients after cardiac surgery. 71 out of 92 identified centers (77.2 %) returned a completed questionnaire. Electrocardiogram, invasive blood pressure, central venous pressure, pulse oximetry, diuresis, body temperature and blood gas analysis were identified as routinely used hemodynamic monitoring, whereas advanced monitoring was performed with pulmonary artery catheter or echocardiography. ⋯ Standard, routinely used monitoring consists of ECG, SpO2, etCO2, invasive BP, CVP, diuresis, body temperature, and BGA. It also shows that there is large variability among the various Centers regarding hemodynamic monitoring of fluid therapy and inotropes administration. Further research is required to better standardize and define the indicators to improve the standards of intensive care after cardiac surgery among Italian cardiac ICUs.
-
J Clin Monit Comput · Jun 2016
Effects of indigo carmine intravenous injection on noninvasive and continuous total hemoglobin measurement.
The effects of an intravenous injection of indigo carmine on noninvasive and continuous total hemoglobin (SpHb) measurement were retrospectively evaluated. The subjects were 21 patients who underwent elective gynecologic surgery under general anesthesia. During surgery, 5 mL of 0.4 % indigo carmine was intravenously injected, and subsequent changes in SpHb concentrations were evaluated. ⋯ The time to reach the minimum value was 4 min, and the time to return to the pre-injection value was 15 min. The decrease in SpHb was greater in the group with a perfusion index (PI) < 1.4 than in the group with a PI > 1.4. The assessment of SpHb after an intravenous injection of indigo carmine necessitates caution.
-
J Clin Monit Comput · Jun 2016
Comparative StudyComparison of train-of-four ratios measured with Datex-Ohmeda's M-NMT MechanoSensor™ and M-NMT ElectroSensor™.
Neuromuscular blockade is usually monitored using train-of-four (TOF) stimulation pattern. A TOF ratio of higher than 90 % is recommended to reduce the risk of adverse effects after anaesthesia. TOF ratio 90 % is used in clinical practice with all different neuromuscular monitors. ⋯ After anaesthetic induction, but before administration of rocuronium, both TOF sensor values drifted from the TOF value of 1.0, showing either significant spontaneous fade (T1 > T4) or tendency of reverse fade (T1 < T4). KMG overestimates the recovery from neuromuscular blockade when compared with EMG. KMG and EMG cannot be used interchangeably, and TOF ratio 90 % cannot be considered as adequate level of recovery with all monitoring devices.