Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2020
Comparative StudyComparison of cardiovascular parameter estimation methods using swine data.
In this study, new and existing methods of estimating stroke volume, cardiac output and total peripheral resistance from analysis of the arterial blood pressure waveform were tested over a wide range of conditions. These pulse contour analysis methods (PCMs) were applied to data obtained in six swine during infusion of volume, phenylephrine, dobutamine, isoproterenol, esmolol and nitroglycerine as well as during progressive hemorrhage. Performance of PCMs was compared using true end-ejection pressures as well as estimated end-ejection pressures. ⋯ The most accurate estimation of end-ejection was obtained when that fraction was set to 60% for the central arterial pressure and to 50% for the femoral and radial arterial pressures. When the estimated end-ejection measures were used for the PCMs that depend on end-ejection measures and when radial artery pressure was used as the input, only Wesseling's Corrected Impedance method and the modified Herd's method achieved statistically superior results. This study provides a systematic comparison of multiple PCMs' ability to estimate stroke volume, cardiac output, and total peripheral resistance and introduces a new method of estimating end-systole.
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J Clin Monit Comput · Apr 2020
Randomized Controlled Trial Observational Study Retracted PublicationThe effects of a recruitment manoeuvre with positive end-expiratory pressure on lung compliance in patients undergoing robot-assisted laparoscopic radical prostatectomy.
The effects of a recruitment manoeuvre (RM) with positive end-expiratory pressure (PEEP) on lung compliance (CLUNG) are not well characterised in robot-assisted laparoscopic radical prostatectomy (RARP). Patients were allocated to group R (n = 10; with an RM) or C (n = 9; without an RM). An RM involved sustained inflation of 30 cmH2O for 30 s. ⋯ CLUNG significantly decreased from pre-op to RARP0 and did not significantly increase from RARP0 to RARP5.1 and RARP5.2 in either group. CLUNG differed significantly between groups at RARP5.1 and RARP5.2 (103 ± 30 vs. 68 ± 11 mL cm-1 H2O and 106 ± 35 vs. 72 ± 9 mL cm-1 H2O; P < 0.05). In patients undergoing RARP, with the addition of RM, the CLUNG was effectively increased from the horizontal lithotomy position to the steep Trendelenburg lithotomy position under pneumoperitoneum.
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J Clin Monit Comput · Apr 2020
Optimizing B-lines on lung ultrasound: an in-vitro to in-vivo pilot study with clinical implications.
B-lines on lung ultrasound (US) are the hallmark of pulmonary edema. It is unknown if ultrasound machine settings or probe type matter. We created an in-vitro gelatin model. ⋯ The experiment was then repeated in-vivo in a patient with known pulmonary edema. Based on a multivariable regression LS-ratings were similar when comparing the in-vitro versus in-vivo experiment (P = 0.16; partial R2 = 0.2%) and when using the curvilinear versus linear probe (P = 0.69; partial R2 = 0.02%) but significantly different across machine settings (P < 0.0001; partial R2 = 34.4%). Limited by its pilot character, our study suggests that (1) certain US-machine settings heavily impact B-line visibility, with no clear difference between probes; (2) in-vitro models are a valid and practical alternative to more challenging patient-based research; (3) there is significant potential to improve B-line visibility and thus diagnostic yield in the clinical setting by using lung presets, centering the focal zone at the pleural line and increasing the distal time gain compensation, most of which are (in our experience) rarely done.