Journal of clinical monitoring and computing
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J Clin Monit Comput · Jun 2017
Monitoring of total positive end-expiratory pressure during mechanical ventilation by artificial neural networks.
Ventilation treatment of acute lung injury (ALI) requires the application of positive airway pressure at the end of expiration (PEEPapp) to avoid lung collapse. However, the total pressure exerted on the alveolar walls (PEEPtot) is the sum of PEEPappand intrinsic PEEP (PEEPi), a hidden component. To measure PEEPtot, ventilation must be discontinued with an end-expiratory hold maneuver (EEHM). ⋯ ANN agreement with reference PEEPtotwas assessed with the Bland-Altman method. Bland Altman analysis of estimation error by ANN showed -0.40 ± 2.84 (expressed as bias ± precision) and ±5.58 as limits of agreement (data expressed as cmH2O). The ANNs estimated the PEEPtotwell at different levels of PEEPappunder dynamic conditions, opening up new possibilities in monitoring PEEPiin critically ill patients who require ventilator treatment.
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J Clin Monit Comput · Jun 2017
Effects of prolonged ischemia on human skeletal muscle microcirculation as assessed by near-infrared spectroscopy.
Near-infrared spectroscopy (NIRS) has been used to detect in vivo microvascular alterations by means of a vascular occlusion test. We sought to analyse by NIRS the microcirculatory profile of patients undergoing prolonged tourniquet-induced bloodless condition for extremity surgery, and compare the results with time of ischemia and comorbidities. We conducted a prospective observational study on 42 patients undergoing upper limb surgery. ⋯ Hyperaemic peak was lower in the 90 min group (83.9 ± 6.8 vs. 91.2 ± 5.7 %, p = 0.02) whereas the hyperaemic time was significantly increased (595 ± 136 vs. 429 ± 107 min, p < 0.001). Alterations of skeletal muscle microcirculation were correlated with the duration of ischemia, but not with comorbidities. We observed an initial impairment of the microcirculatory recovery at 90 min of ischemia.
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J Clin Monit Comput · Jun 2017
Observational StudyConsistency of cardiac function index and global ejection fraction with global end-diastolic volume in patients with femoral central venous access for transpulmonary thermodilution: a prospective observational study.
Global ejection fraction (GEF) and cardiac function index (CFI) are transpulmonary thermodilution (TPTD)-derived indices of the systolic function. Their validity relies on an accurate determination of the global end-diastolic volume (GEDV). Due to an overestimation of GEDV using a femoral central venous catheter (CVC) a correction formula for indexed GEDV (GEDVI) has been implemented in the latest PiCCO™-algorithm. ⋯ By contrast, GEFcalculated (23.1 ± 8.7 %) was not substantially different from GEFdisplayed (22.4 ± 8.6 %). Although GEDV and GEF are corrected for femoral CVC site, this does not apply to CFI. However, all indices derived from GEDV should be calculated consistently.