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Objective: The aim of this study was to validate the revised SenTec V-Sign 2 sensor (SenTec AG, Therwil, Switzerland) for combined noninvasive continuous assessment of pulse rate, pulse oximetry (SpO2), and transcutaneous carbon dioxide tension (PtcCO2) in adults after cardiac surgery. Design: A prospective clinical study. Setting: A single-center university hospital. Participants: Twenty adult patients aged 36 to 84 years after cardiac surgery. Interventions: SpO2 and PtcCO2 values of three V-Sign 2 sensors (SenTec AG) attached at the earlobe, forehead, and cheek and SpO2 values of the Nellcor Durasensor (Model DS-100A; Nellcor Puritan Bennett Inc, Pleasanton, CA) were compared with simultaneous measurements of blood gases and end-expiratory carbon dioxide. Measurements and Main Results: Measurements were performed during periods of hyper-, normo-, and hypocapnia and then at 30-minute intervals up to 5 hours. Bland-Altman analysis and simple regression analysis were used. Results: The detection failures for PtcCO2 were 0.3% to 1.3%, for SpO2 10% to 25%, and for pulse rate 5% to 10%. The V-Sign 2 earlobe sensor provided the best results. The mean bias and limits of agreement for PtcCO2ear and PaCO2 were 1.1 and −3.4/+5.5 mmHg. The drift of PtcCO2 was negligible at all locations. The mean bias and limits of agreement of V-Sign SpO2ear and SaO2, as well as V-Sign pulse rate and the electrocardiogram, were −1.7% and −6.8/+3.9% and 1.2 beats/min and −3.3/+5.8 beats/min. End-expiratory carbon dioxide showed a weak correlation with PaCO2 (r 2 = 0.47). Conclusions: Transcutaneous capnometry using the revised V-Sign 2 sensor at the earlobe is a reliable monitoring tool during the recovery period of patients after cardiac surgery. This approach has the potential to reduce the number of arterial blood gas samples. [Copyright &y& Elsevier]

Objective: The study''s aim was to compare response entropy (RE) and state entropy (SE) with bispectral index (BIS) electroencephalography (EEG) as an alternative cerebral monitoring tool in patients scheduled for coronary artery bypass graft surgery. Design: Prospective, observational single-center study. Setting: University hospital. Participants: Thirty patients undergoing coronary artery bypass graft surgery receiving remifentanil-propofol anesthesia. Interventions: Surgery was performed with cardiopulmonary bypass (CPB) and cardiac arrest in 15 patients, with CPB without cardiac arrest in 9 patients and without CPB in 6 patients. Measurements and Main Results: RE, SE, BIS, burst suppression ratio (BSR), and frontal electromyography (f-EMG) were detected simultaneously. RE and SE compared favorably with BIS and their correlations were strong (r 2 = 0.6, r 2 = 0.55, respectively). The mean bias of RE and BIS was −1.8, but limits of agreement were high (+20.5/−24.1). RE and SE tended to be lower than the BIS values in the CPB subgroups. The detection of BSR was similar with RE and SE and the BIS. A strong correlation existed between BIS and f-EMG (r 2 = 0.62) in contrast to RE (r 2 = 0.45) and SE (r 2 =0.39). BIS monitoring was significantly more disturbed than RE and SE with 9.1% ±10.9% and 0.1% ± 0.2% of the total anesthesia time, respectively. Neither implicit nor explicit memory was shown. Conclusion: RE and SE are comparable with the BIS but showed significantly less interference from f-EMG and superior resistance against artifacts. Thus, spectral entropy is more suitable than the BIS during propofol-remifentanil anesthesia in cardiac surgery patients. [Copyright &y& Elsevier]

Objective: Cerebral near-infrared spectroscopy (NIRS) was evaluated for use in monitoring global oxygenation in adult patients after cardiac surgery. Design: Prospective, randomized clinical monitoring study. Setting: Intensive care unit for cardiac surgery; university hospital. Participants: The study included 35 patients scheduled for cardiac surgery with insertion of a pulmonary artery catheter; patients with known cerebral-vascular perfusion disturbances were excluded. Interventions: Noninvasive cerebral NIRS oxygen saturation (rSO2) and conventional intensive care monitoring parameters were assessed. Measurements and Main Results: Simple regression analysis was used to assess the correlation of rSO2 to hemodynamic parameters. There was fair-to-moderate intersubject correlation to hemoglobin concentration (r = 0.45, p < 0.0001) and mixed venous oxygen saturation (SmvO2) (r = 0.33, p < 0.0001). Sensitivity and specificity of rSO2 to detect substantial (≥1 standard deviation) changes in mixed venous oxygen saturation were 94% and 81%, respectively. Conclusions: Cerebral NIRS in adult patients might not be the tool to replace mixed venous oxygen monitoring. Further work has to be done to assess its potential to reflect intraindividual trends. [Copyright &y& Elsevier]