Journal of clinical monitoring and computing
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J Clin Monit Comput · Jun 2012
Case ReportsTransesophageal echocardiography and intraoperative phlebotomy during surgical repair of coarctation of aorta in a patient with atrial septal defect, moderately severe mitral regurgitation and severe pulmonary hypertension.
Acute left ventricular (LV) or right ventricular (RV) dysfunction during repair of coarctation of aorta (CoA) is rare. Well-developed collateral circulation between branches of both the subclavian arteries (SCAs) and upper descending thoracic aorta decompress LV and prevents acute rise in afterload. An adult patient presented for CoA repair. ⋯ Both the SCAs were filling retrograde. A unique anatomy in which aortic-clamping proximal to CoA and both the SCAs would increase flow to spinal-cord as clamping of the SCAs will stop stealing of blood into the CoA but potentially increase LV afterload, MR, left to right shunt across ASD and RV volume and pressure load depending on the magnitude of flow across the CoA. The increases in LV afterload, MR, and RV afterload and volume overload were managed by controlled phlebotomy and fine-tuned by manipulating inhaled isoflurane concentration whereas the Transesophageal echocardiography (TEE) monitored and guided the management.
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J Clin Monit Comput · Jun 2012
Visual estimation of pulse pressure variation is not reliable: a randomized simulation study.
Pulse pressure variation (PPV) can be monitored several ways, but according to recent survey data it is most often visually estimated ("eyeballed") by practitioners. It is not known how accurate visual estimation of PPV is, or whether eyeballing of PPV in goal-directed fluid therapy studies may limit the ability to blind the control group to PPV value. The goal of this study was to test the accuracy of visual estimation of PPV. ⋯ The rate of correct response group classification was 65 %. Mean percent error was higher the faster the waveform sweep speed (130 % at 25 mm/s vs. 117 % at 6.25 mm/s), and correct responsiveness classification lower (58 % at 25 mm/s vs. 69 % at 6.25 mm/s). The results from this study show that eyeballing the arterial pressure waveform in order to evaluate pulse pressure variation is not accurate.
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J Clin Monit Comput · Jun 2012
States of low pulmonary blood flow can be detected non-invasively at the bedside measuring alveolar dead space.
We tested whether the ratio of alveolar dead space to alveolar tidal volume (VD(alv)/VT(alv)) can detect states of low pulmonary blood flow (PBF) in a non-invasive way. Fifteen patients undergoing cardiovascular surgeries with cardiopulmonary bypass (CPB) were studied. CPB is a technique that excludes the lungs from the general circulation. ⋯ At CPB of 80, 60, 40 and 20 % VD(Bohr)/VT was 0.64 ± 0.06, 0.55 ± 0.06, 0.47 ± 0.05 and 0.40 ± 0.04, respectively; p < 0.001 and VD(alv)/VT(alv) 0.53 ± 0.07, 0.40 ± 0.07, 0.29 ± 0.06 and 0.25 ± 0.04, respectively; p < 0.001). After CPB, VD(Bohr)/VT and VD(alv)/VT(alv) reached values similar to baseline (0.37 ± 0.04 and 0.19 ± 0.06, respectively). At constant ventilation the alveolar component of VD(Bohr)/VT increased in proportion to the deficit in lung perfusion.
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Small changes in the frequency of the electromyography could reflect an inadequate anesthetic or analgesic level, and it could be more specific than the hemodynamic monitors. The Datex-Ohmeda S/5 Entropy Module includes information about the electromyographic activity of the face muscles (response entropy--RE). The aim of our study is compare entropy and BIS ability to detect a nociceptive stimulus during a sevoflurane anesthesia. ⋯ There was a significant difference between RE and SE post-noxious stimulus values at 3 and 4 % end-tidal sevoflurane (p < 0.05). Only RE changed significantly at the moment of the noxious stimulation at both sevoflurane concentrations studied (p < 0.05). In patients under general anesthesia only carried out with sevoflurane at concentrations that inhibit the movement to painful stimuli, the RE is a single parameter able to detect variations after the nociceptive stimulation.