Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2022
Multi-analyte calibration and verification of a multi-parameter laser-based pulse oximeter.
Almost since its introduction pulse oximetry was known to overestimate oxygen saturation in cases of carbon monoxide poisoning or elevated methemoglobin (metHb) levels. To eliminate this dangerous behavior some manufacturers have added additional LED emitters to try to increase the number of measured hemoglobin species and to improve measurement accuracy, but have not been very successful. We hypothesized that the use of narrow-band laser light sources would make accurate and precise measurement of the four primary species of hemoglobin possible, even in cases of elevated levels of carboxyhemoglobin (COHb). ⋯ This laser-based pulse oximeter measured all four species of hemoglobin accurately and precisely (ARMS ≤ 1.8%) for metHb levels in the clinically normal range. At elevated metHb levels the device continued to provide accurate and precise measurements of metHb and RHb (ARMS ≤ 1.7%). The use of monochromatic laser light sources can create a new generation of highly accurate, multi-parameter, pulse oximeters.
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The operation of the BIS monitor remains undescribed, despite 20 years of clinical use and 3000 academic articles. The core algorithmic software (the BIS Engine) can be retrieved from the motherboard of the A-2000 monitor in binary form through forensic disassembly using debugging interfaces left in place by the original designers, opening the possibility of executing the BIS algorithms on contemporary computers through emulation. Three steps were required for emulation. ⋯ Additive white noise in the EEG caused a progressive lifting and flattening of BIS values. Emulation replicates BIS Engine behavior, allowing calculation upon existing EEG datasets or signals from other, potentially remote or wireless, devices. Emulation provides advantages for elucidating the mathematical expression of the algorithms, which remain important as practical constraints on any hypothetical mechanism of action of anesthetics.
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J Clin Monit Comput · Apr 2022
A novel method of trans-esophageal Doppler cardiac output monitoring utilizing peripheral arterial pulse contour with/without machine learning approach.
Transesophageal Doppler (TED) velocity in the descending thoracic aorta (DA) is used to track changes in cardiac output (CO). However, CO tracking by this method is hampered by substantial change in aortic cross-sectional area (CSA) or proportionality between blood flow to the upper and lower body. To overcome this, we have developed a new method of TED CO monitoring. ⋯ Between CODA-ML and COref, concordance rate was 93% and angular concordance rate was 94%. Both COAA-CSA and CODA-ML demonstrated "good to marginal" tracking ability of COref. In conclusion, our method may allow a robust and reliable tracking of CO during perioperative hemodynamic management.
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J Clin Monit Comput · Apr 2022
LetterUse of flexible video bronchoscope for verification of nasogastric tube position in the intubated patient.
We propose a novel method for verifying the nasogastric tube (NGT) position and tip localization using flexible video bronchoscopy in anesthetized and intubated adult patients. The length of the scope used is 65 cm and can thus, track the NGT up to the pyloric canal. We have used this technique in patients with success. ⋯ The stomach is identified by the red mucosa and random tortuous folds (Fig. 1b). The pyloric canal can be identified by the convergence of gastric mucosal folds leading to the pyloric opening (Fig. 1c). In each case, the subdiaphragmatic position of NGT was verified with radiography, which is a routine practice in our institute.
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J Clin Monit Comput · Feb 2022
Randomized Controlled TrialComparison of two forced air warming systems for prevention of intraoperative hypothermia in carcinoma colon patients: a prospective randomized study.
Hypothermia is common occurrence in patients undergoing colonic surgeries. We hypothesized that the underbody forced air warming blankets will be better than conventional over-body forced air warming blankets for prevention of hypothermia during laparoscopic colon surgeries. After ethics approval, sixty patients undergoing elective laparoscopic colon surgeries were randomly divided into two groups to receive warming by underbody forced air warming blanket (n = 30) or over-body forced air warming blanket (n = 30). ⋯ Underbody and over-body blankets were comparably effective in preventing hypothermia in patients undergoing laparoscopic colorectal surgery under general anaesthesia. Trial registration CTRI (2019/06/019,576). Date of Registration: June 2019, Prospectively registered.