Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2018
Observational StudyA mesenteric traction syndrome affects near-infrared spectroscopy evaluated cerebral oxygenation because skin blood flow increases.
During abdominal surgery manipulation of internal organs may induce a "mesenteric traction syndrome" (MTS) including a triad of flushing, hypotension, and tachycardia that lasts for about 30 min. We evaluated whether MTS affects near-infrared spectroscopy (NIRS) assessed frontal lobe oxygenation (ScO2) by an increase in forehead skin blood flow (SkBF). The study intended to include 10 patients who developed MTS during pancreaticoduodenectomy and 22 patients were enrolled (age 61 ± 8 years; mean ± SD). ⋯ MTS developed 20 min (12-24; median with range) after the start of surgery and heart rate (78 ± 16 vs. 68 ± 17 bpm; P = 0.0032), CO (6.2 ± 1.4 vs. 5.3 ± 1.1 L min-1; P = 0.0086), SkBF (98 ± 35 vs. 80 ± 23 PU; P = 0.0271), and ScO2 (71 ± 6 vs. 67 ± 8%; P < 0.0001), but not MCA Vmean (32 ± 8 vs. 32 ± 7; P = 0.1881) were largest in the patients who developed MTS. In some patients undergoing abdominal surgery NIRS-determined ScO2 is at least temporarily affected by an increase in extra-cranial perfusion independent of cerebral blood flow as indicated by MCA Vmean. Thus, NIRS evaluation of ScO2 may overestimate cerebral oxygenation if patients flush during surgery.
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J Clin Monit Comput · Apr 2018
Comparative StudyA comparison of volume clamp method-based continuous noninvasive cardiac output (CNCO) measurement versus intermittent pulmonary artery thermodilution in postoperative cardiothoracic surgery patients.
The CNAP technology (CNSystems Medizintechnik AG, Graz, Austria) allows continuous noninvasive arterial pressure waveform recording based on the volume clamp method and estimation of cardiac output (CO) by pulse contour analysis. We compared CNAP-derived CO measurements (CNCO) with intermittent invasive CO measurements (pulmonary artery catheter; PAC-CO) in postoperative cardiothoracic surgery patients. In 51 intensive care unit patients after cardiothoracic surgery, we measured PAC-CO (criterion standard) and CNCO at three different time points. ⋯ For CNCOcal, the mean difference was -0.3 L/min (±0.5 L/min; -1.2 to +0.7 L/min) with a percentage error of 19%. In this clinical study in cardiothoracic surgery patients, CNCOcal showed good agreement when compared with PAC-CO. For CNCObio, we observed a higher percentage error and good trending ability (concordance rate 100%).
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J Clin Monit Comput · Apr 2018
Comparative Study Observational StudyFour-wavelength near-infrared peripheral oximetry in cardiac surgery patients: a comparison between EQUANOX and O3.
Near-infrared spectroscopy (NIRS) is a continuous and noninvasive technology that measures regional tissue oxygen saturation (rSO2). A new 4-wavelength generation of NIRS monitors is now available. We aimed to compare peripheral somatic rSO2 values given by the 4-wavelength EQUANOX™ 7600 device (Nonin Medical Inc., Plymouth, Mn) and O3™ device (Masimo Corporation, Irvine, CA). ⋯ Bias was 4.0% and limits of agreement were ±26.3%. Significant correlations were evidenced between EQUANOX and O3 rSO2 absolute values: rho = 0.758 (95% CI 0.701-0.806), P < 0.0001, and rSO2 percent maximum difference versus baseline: rho = 0.582 (95% CI 0.188-0.815), P = 0.007. While absolute values of rSO2 given by both devices were equivalent and well correlated, the clinical agreement is probably not acceptable, meaning that EQUANOX and O3 are not interchangeable in routine practice.
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J Clin Monit Comput · Apr 2018
Microvascular reactivity measured by vascular occlusion test is an independent predictor for postoperative bleeding in patients undergoing cardiac surgery.
The purpose of the study is to investigate the relationship between microvascular reactivity and postoperative bleeding in cardiac surgery. The authors retrospectively analyzed a prospectively collected registry of cardiac surgery patients. Data from 154 patients enrolled in the registry were analyzed. ⋯ In the multivariable adjusted model, the effect of StO2 recovery slope on postoperative CTO (log-transformed) was statistically significant, and the degree of StO2 recovery slope was inversely related to the amount of CTO (exp(estimate) = 0.935; exp(95% CI) 0.881-0.992; p = 0.027). StO2 recovery slope was also inversely associated with postoperative PRBC transfusion possibility (OR = 0.795; 95% CI 0.633-0.998; p = 0.048). Microvascular reactivity measured by VOT is independently and inversely associated with postoperative bleeding in patients undergoing cardiac surgery.
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J Clin Monit Comput · Apr 2018
Predicting fluid responsiveness in whom? A simulated example of patient spectrum influencing the receiver operating characteristics curve.
The influence of patient spectrum on the sensitivities and specificities of diagnostic methods has been termed spectrum bias or spectrum effect. Receiver operating characteristics curves are often used to assess the ability of diagnostic methods to predict fluid responsiveness. As a receiver operating characteristics curve is a presentation of sensitivity and specificity, the purpose of the present manuscript was to explore if patient spectrum could affect areas under receiver operating characteristics curves and their gray zones. ⋯ Simulated patient populations with stroke volume variation values between 5 and 15 or 3 and 25% had median (2.5th-97.5th percentiles) areas under receiver operating characteristics curves of 0.79 (0.65-0.90) and 0.93 (0.85-0.99), respectively. The gray zones indicating range of diagnostic uncertainty were also affected. The patient spectrum can affect common statistics from receiver operating characteristics curves, indicating the need for considering patient spectrum when evaluating the abilities of different methods to predict fluid responsiveness.