Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2022
Observational StudyVelocity-pressure loops can estimate intrinsic and pharmacologically induced changes in cardiac afterload during non-cardiac surgery. An observational study.
Continuous measurement of aortic pressure and aortic flow velocity signals in the operating theatre allows us to draw velocity-pressure (Vel-Pre) loops. The global afterload angle (GALA), derived from the Vel-Pre loops, has been linked to cardiac afterload indicators. As age is the major determinant of constitutive arterial stiffness, we aimed to describe (1) the evolution of the GALA according to age in a large cohort of anesthetized patients and (2) GALA variations induced by haemodynamic interventions. ⋯ In non-cardiac surgery, the GALA seems to be associated with both intrinsic rigidity (reflected by age) and pharmacologically induced vasoconstriction changes (by vasopressors). In addition, the GALA can discriminate the differential effects of phenylephrine and noradrenaline. These results should be confirmed in a prospective, ideally randomized, trial.
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J Clin Monit Comput · Apr 2022
Effects of PEEP on the relationship between tidal volume and total impedance change measured via electrical impedance tomography (EIT).
Electrical impedance tomography (EIT) is used in lung physiology monitoring. There is evidence that EIT is linearly associated with global tidal volume (VT) in clinically healthy patients where no positive end-expiratory pressure (PEEP) is applied. This linearity has not been challenged by altering lung conditions. ⋯ The variance in VTEIT was best described by peak inspiratory pressure (PIP) and PEEP (adjusted R2 0.82) while variance in VTSpiro was best described by PIP and airway deadspace (adjusted R2 0.76). The relationship between VTEIT and VTSpiro remains linear with changes in tidal volume, and stable across altered lung conditions. This may have application for monitoring and assessment in vivo.
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J Clin Monit Comput · Apr 2022
Pupillary unrest, opioid intensity, and the impact of environmental stimulation on respiratory depression.
Opioid-induced respiratory depression (OIRD) confers significant morbidity, but its onset can be challenging to recognize. Pain or stimulation effects of conversation may mask or attenuate common clinical manifestations of OIRD. We asked whether pupillary unrest could provide an objective signal of opioid exposure, and whether this signal would be independent from the confounding influence of extrinsic stimulation. ⋯ PUAL is a consistent indicator of opioid effect, and distinguishes higher opioid concentrations independently of the stimulating effects of conversational interaction. Under equivalent opioid exposure, conversational interaction delayed the onset and minimized the severity of OIRD. Clinical trial registration: NCT04301895.
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J Clin Monit Comput · Apr 2022
Nociception level index: do intra-operative values allow the prediction of acute postoperative pain?
Nociception Level Index (NOL) guided analgesia has previously been found to correlate with noxious stimuli during surgery. It was aim of this study to investigate the relationship between intra-operative NOL and acute postoperative pain. After IRB approval, 80 patients scheduled for non-emergency surgery were enrolled. ⋯ The NOL reaction to skin incision, but not NOL during surgery appears to allow the exclusion and, to a lesser degree the prediction of moderate-severe pain in PACU. The results may also strengthen the manufacturers recommendation of an intraoperative NOL range of 10-25. Australian New Zealand Clinical Trials Registry: ACTRN12619001596190.
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J Clin Monit Comput · Apr 2022
Assessment of the 50 % and 95 % effective paratracheal forces for occluding the esophagus in anesthetized patients.
This study aimed to evaluate the 50% and 95% effective paratracheal forces for occluding the esophagus in anesthetized patients. In 46 anesthetized patients, the upper esophagus was examined using ultrasonography, and the lower paratracheal area over the esophagus just above the clavicle was marked. Manual paratracheal force was applied over that area using a novel pressure sensing device set-up. ⋯ According to Dixon and Mood method, the 50% effective paratracheal force (confidence interval) was 18.4 (17.5‒19.3) N with the use of a 12-Fr esophageal stethoscope and 12.8 (11.0‒14.6) N with the use of an 18-Fr esophageal stethoscope. Using probit regression analysis, the 50% and 95% effective paratracheal forces were 18.4 (16.8‒19.6) N and 20.6 (19.4‒27.9) N, respectively, with the use of a 12-Fr esophageal stethoscope, and 12.4 (8.3‒14.4) N and 16.9 (14.7‒37.3) N, respectively, with the use of an 18-Fr esophageal stethoscope. Our findings suggest a guide for applying paratracheal force during rapid sequence induction and tracheal intubation.