Journal of clinical monitoring最新文献

{"title":"The response of anesthetic agent monitors to trifluoromethane warns of the presence of carbon monoxide from anesthetic breakdown.","authors":"H J Woehlck,&nbsp;M B Dunning,&nbsp;A H Kulier,&nbsp;F J Sasse,&nbsp;K Nithipataikom,&nbsp;D W Henry","doi":"10.1023/a:1007390722425","DOIUrl":"https://doi.org/10.1023/a:1007390722425","url":null,"abstract":"<p><strong>Objective: </strong>Trifluoromethane and CO are produced simultaneously during the breakdown of isoflurane and desflurane by dry CO2 absorbents. Trifluoromethane interferes with anesthetic agent monitoring, and the interference can be used as a marker to indicate anesthetic breakdown with CO production. This study tests representative types of gas monitors to determine their ability to provide a clinically useful warning of CO production in circle breathing systems.</p><p><strong>Methods: </strong>Isoflurane and desflurane were reacted with dry Baralyme at 45 degrees C. Standardized samples of breakdown products were created from mixtures of reacted and unreacted gases to simulate the partial degrees of reaction which might result during clinical episodes of anesthetic breakdown using 1% or 2% isoflurane and 6% or 12% desflurane. These mixtures were measured by the monitors tested, and the indication of the wrong agent or a mixture of agents due to the presence of trifluoromethane was recorded and related to the CO concentration in the gas mixtures.</p><p><strong>Results: </strong>When presented with trifluoromethane from anesthetic breakdown, monochromatic infrared monitors displayed inappropriately large amounts of isoflurane or desflurane. Agent identifying infrared and Raman scattering monitors varied in their sensitivity to trifluoromethane. Mass spectrometers measuring enflurane at mass to charge = 69 were most sensitive to trifluoromethane.</p><p><strong>Conclusion: </strong>Monochromatic infrared monitors were unable to indicate anesthetic breakdown via interference by trifluoromethane, but did indicate falsely elevated anesthetic concentrations. Agent identifying infrared and Raman monitors provided warning of desflurane breakdown via the interference of trifluoromethane by displaying the wrong agent or mixed agents, but may not be sensitive enough to warn of isoflurane breakdown Some mass spectrometers provided the most sensitive warnings to anesthetic breakdown via trifluoromethane, but additional data processing by some patients monitor units reduced their overall effectiveness.</p>","PeriodicalId":77199,"journal":{"name":"Journal of clinical monitoring","volume":"13 3","pages":"149-55"},"PeriodicalIF":0.0,"publicationDate":"1997-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/a:1007390722425","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20177828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the AVOXimeter: precision, long-term stability, linearity, and use without heparin.","authors":"S R Bailey,&nbsp;E L Russell,&nbsp;A Martinez","doi":"10.1023/a:1007308616686","DOIUrl":"https://doi.org/10.1023/a:1007308616686","url":null,"abstract":"<p><strong>Objectives: </strong>Because the AVOXimeter uses disposable cuvettes and makes its measurements directly in whole blood without first hemolyzing the sample, it does not need the care and maintenance that conventional co-oximeters require, it operates faster than conventional co-oximeters, and it is less expensive. Therefore, the objectives of the study were (1) to evaluate the precision and linearity of the AVOXimeter's measurements of total hemoglobin concentration and oxyhemoglobin saturation; (2) to assess its long-term stability and thus the required interval for recalibration; (3) to determine whether measurements can be made without anticoagulants; and (4) to assess the feasibility of storing blood samples in the disposable cuvettes.</p><p><strong>Methods: </strong>Measurements made by the test instrument were compared with those of conventional co-oximeters or with standardized hemoglobin solutions. Blood samples were also collected with and without heparin to determine whether anticoagulation is necessary.</p><p><strong>Results: </strong>Our tests confirmed the specified precision of 0.3 g/dl for total hemoglobin and 0.5% for oxyhemoglobin. The results also showed that these measurements were linear when compared with a conventional co-oximeter, and they were consistent with the specified accuracy of 0.45 g/dl for total hemoglobin and 1% for oxyhemoglobin. Weekly checks with control solutions showed that the instrument holds its calibration for a year or more. Although treating syringes with heparin caused dilution errors, heparin did not affect the measurements when dilution was avoided. When blood samples were placed in disposable cuvettes and read repeatedly at 1-min intervals for 20 min, the readings drifted appreciably away from the original value. This drift occurred so slowly that readings taken at the first and second minute after the cuvette was filled were within 1 or 2% of the original reading.</p><p><strong>Conclusions: </strong>In our experience the test instrument was simple and easy to operate. It met the specification for precision and accuracy, its measurements were highly linear, and it maintained a stable calibration for one year. If the cuvettes are filled as soon as blood is drawn, anticoagulation is unnecessary. However, the cuvettes should be read with 1 min of filling the cuvette.</p>","PeriodicalId":77199,"journal":{"name":"Journal of clinical monitoring","volume":"13 3","pages":"191-8"},"PeriodicalIF":0.0,"publicationDate":"1997-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/a:1007308616686","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20178402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response time studies of a new, portable mass spectrometer.","authors":"P A Delaney,&nbsp;G M Barnas,&nbsp;C F Mackenzie","doi":"10.1023/a:1007353818448","DOIUrl":"https://doi.org/10.1023/a:1007353818448","url":null,"abstract":"<p><strong>Objective: </strong>Mass spectrometers are frequently used by anesthesiologists perioperatively to monitor patients' respiratory function and levels of inhaled anesthetics. Due to size, complexity and expense, they are typically used in a time-sharing manner which degrades their performance. We assessed the accuracy of the Random Access Mass Spectrometer (RAMS), Marquette Electronics) which is small enough to be dedicated to a single patient.</p><p><strong>Methods: </strong>We compared the 10-90% rise times for O2, CO2, N2O and isoflurane for the RAMS with different catheter configurations to those of a MedSpect mass spectrometer (Allegheny International Medical Technology) operating under ideal conditions. For CO2 the lag of the RAMS relative to the MedSpect was also measured. Next, perioperative conditions were stimulated by ventilating anesthetized dogs with a variety of inhalatory gases and ventilatory parameters, and the interchangeability of the two devices was assessed.</p><p><strong>Results: </strong>When fitted with a catheter with minimal dead space the MedSpect had rise times of 0.11-0.12 sec while the RAMS had rise times of 0.07-0.12 sec and a delay of 0.19 sec compared to the MedSpect. The rise times and delay of the RAMS increased when using a larger catheter and water trap. Although there were statistically significant differences in some values for inhaled and end-tidal gases under simulated perioperative conditions, particularly at the higher frequencies, these differences were small and for most purposes not clinically significant.</p><p><strong>Conclusions: </strong>Our results demonstrate that the RAMS configured for clinical conditions performs nearly as well as the MedSpect under ideal conditions. The small differences between the two, confined almost entirely to their end-tidal CO2 values, could be due to differences in instrument calibration, by the larger sampling catheter commonly used in clinical settings, or by a combination of both factors. Therefore the RAMS is sufficiently accurate for clinical use and would alleviate problems associated with time-shared mass spectrometers.</p>","PeriodicalId":77199,"journal":{"name":"Journal of clinical monitoring","volume":"13 3","pages":"181-9"},"PeriodicalIF":0.0,"publicationDate":"1997-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/a:1007353818448","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20178401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance of anesthesia machines' devices that are not part of the Food and Drug Administration's daily checkout.","authors":"F Dexter,&nbsp;S Coffin,&nbsp;J Woodward","doi":"10.1023/a:1007302030065","DOIUrl":"https://doi.org/10.1023/a:1007302030065","url":null,"abstract":"<p><strong>Objective: </strong>The Food and Drug Administration's (FDA) checkout recommendations are to be applied, at least daily, on anesthesia machines. Devices included in the checkout are crucial to the safe operation of the machine. Remaining devices do not need to be checked as often. However, they should be checked at some appropriate interval. We calculated the reliability of the non-FDA checkout devices, to predict failure rates of these devices.</p><p><strong>Methods: </strong>The study included 36 North American Drager Narkomed anesthesia machines that were in service a total of 109,410 days at a university hospital. Reliability (i.e., statistical) analyses were done using in-house data recorded by biomedical technicians during 3359 monthly machine inspections. If any one device was operating outside of the limits of the manufacturer's specifications, the machine was labeled as having failed its inspection.</p><p><strong>Results: </strong>Assumptions of the failure analysis were satisfied. The mean time between failures equaled 1351 days or 3.7 years (lower 95% confidence bound 1123 days or 3.1 years). The mean daily probability of one or more devices failing to perform within the manufacturer's specification between inspections equaled 1.1, 2.2%, and 4.4% for inspections every 1, 2, or 4 months, respectively. Probabilities that a machine would fail on demand between inspections were approximately equal to the mean daily probabilities of machine failure. The mean number of days per year that a machine would be operating with a device that is outside of the limits of its specifications equaled 4, 8, and 12, days, respectively. The mean daily probabilities of failure and the probabilities of failure on demand were both directly proportional to the inspection interval.</p><p><strong>Conclusions: </strong>Our failure analysis provides a rational basis for choosing an appropriate inspection interval for anesthesia machines' devices that are not included in the FDA's checkout recommendations.</p>","PeriodicalId":77199,"journal":{"name":"Journal of clinical monitoring","volume":"13 3","pages":"171-9"},"PeriodicalIF":0.0,"publicationDate":"1997-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/a:1007302030065","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20178400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An algorithm for real-time, continuous evaluation of left ventricular mechanics by single-beat estimation of arterial and ventricular elastance.","authors":"H Shih,&nbsp;Z Hillel,&nbsp;C Declerck,&nbsp;C Anagnostopoulos,&nbsp;M Kuroda,&nbsp;D Thys","doi":"10.1023/a:1007387315948","DOIUrl":"https://doi.org/10.1023/a:1007387315948","url":null,"abstract":"<p><p>We describe a computer algorithm that allows continuous, real-time evaluation of ventricular elastance (Ees), arterial elastance (Ea), and their coupling ratio in a clinical setting. In the conventional pressure-volume analysis of left ventricular (LV) contractility, invasive methods of volume determination and a significant, rapid preload reduction are required to generate Ees. With the help of automated border detection by transesophageal echocardiography, and a technique of estimating peak LV isovolumic pressure, Ea and Ees were determined from a single cardiac beat without the need for preload reduction. A comparison of results obtained by a conventional approach and the new algorithm technique, showed good correlation for Ea (r = 0.86, p < 0.001) and Ees (r = 0.74, p = 0.001). Bias analysis showed a bias (d) of 1.47 mmHg/cm2 for Ea with a standard deviation (SD) of 7.03 mmHg/cm2, and upper (d+2SD) and lower(d-2SD) limits of agreement of 15.24 mmHg/cm2 and -12.31 mmHg/cm2, respectively. Bias analysis showed a bias of -1.42 mmHg/cm2 for Ees with a SD of 4.88 mmHg/cm2, and limits of agreement of 8.15 mmHg/cm2 and -10.98 mmHg/cm2. The algorithm's stability to artifacts was also analyzed by comparing magnitudes of residuals of Ea and Ees from source signals with and without noise. With Ea differing by an average of 1.036 mmHg/cm2 and Ees differing by an average of 0.836 mmHg/cm2, the algorithm was found to be stable to artifacts in the source signals.</p>","PeriodicalId":77199,"journal":{"name":"Journal of clinical monitoring","volume":"13 3","pages":"157-70"},"PeriodicalIF":0.0,"publicationDate":"1997-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/a:1007387315948","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20177829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cardiac output and circulating blood volume analysis by pulse dye-densitometry.","authors":"T Iijima,&nbsp;T Aoyagi,&nbsp;Y Iwao,&nbsp;J Masuda,&nbsp;M Fuse,&nbsp;N Kobayashi,&nbsp;H Sankawa","doi":"10.1023/a:1007339924083","DOIUrl":"https://doi.org/10.1023/a:1007339924083","url":null,"abstract":"<p><strong>Objective: </strong>Pulse dye-densitometry (PDD) is a newly developed method for monitoring the indocyanine green (ICG) concentration in an artery with which cardiac output (CO) and circulating blood volume (CBV) can be determined. We evaluated its accuracy for clinical use.</p><p><strong>Methods: </strong>In 7 patients under general anesthesia, ICG-sensitive optical probes (805 and 890 nm) were attached to a finger. Following injection of ICG, the arterial concentration of dye was recorded optically by the non-invasive test instrument and sampled arterial blood ICG concentration was also measured photometrically for comparison. In order to validate the PDD analysis, CO was also measured by both the dye dilution cuvette method and by thermodilution in 8 patients scheduled for coronary artery bypass grafting. In 30 other patients, CBV assessed by PDD was compared with its value estimated from body size.</p><p><strong>Results: </strong>The blood dye concentration correlated well with the values obtained by PDD (r = 0.953, p < 0.01). Mean bias for the test PDD CO was +0.15 +/- 0.72 min l-1 (not significant (n.s.)) compared with the cuvette method while the mean bias of the thermodilution method vs the cuvette method was +0.79 +/- 0.84 min l-1 (p < 0.0001.). The average value of CBV obtained by PDD was 3.81 +/- 1.39 L compared with that estimated value, 3.72 +/- 0.77 L (n.s.).</p><p><strong>Conclusions: </strong>CO determined by PDD agrees well with cuvette densitometry, and somewhat less well with CO by thermodilution. The new method, by not requiring a pulmonary arterial catheter, is less invasive than either older method, and yields in addition a value of CBV.</p>","PeriodicalId":77199,"journal":{"name":"Journal of clinical monitoring","volume":"13 2","pages":"81-9"},"PeriodicalIF":0.0,"publicationDate":"1997-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/a:1007339924083","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20060272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of movement artefact by the Nellcor N-200 and N-3000 pulse oximeters.","authors":"J L Plummer,&nbsp;A H Ilsley,&nbsp;R R Fronsko,&nbsp;H Owen","doi":"10.1023/a:1007303104811","DOIUrl":"https://doi.org/10.1023/a:1007303104811","url":null,"abstract":"<p><strong>Objectives: </strong>The Nellcor N-3000 pulse oximeter is designed to be able to identify signal artefact related to movement of the body part to which the probe is attached. It may therefore provide a reliable means of monitoring arterial oxyhemoglobin saturation (SpO2) in awake, moving patients. This study compared the Nellcor N-3000 and N-200 pulse oximeters in terms of their ability to identify readings associated with movement, in a group of volunteers making standardized movements.</p><p><strong>Methods: </strong>Thirty-six volunteers were studied. Volunteers breathed room air throughout the study. SpO2 of each volunteer was monitored by both a Nellcor N-200 and a Nellcor N-3000 simultaneously on both hands. Volunteers made a series of five standardized movements, each lasting one minute, with each hand during the monitoring session, while SpO2 and oximeter status were recorded from all four oximeters. The mean SpO2 reading was calculated during each movement. SpO2 readings which the oximeter identified as being associated with movement, pulse search not locked, sensor not attached, or break in communications were excluded from analysis.</p><p><strong>Results: </strong>The N-3000 rejected from 17 to 78% of readings taken during movement, compared to 0 to 2% with the N-200. Although the remaining readings of both types of oximeters were subject to some movement artefact, which led to spuriously low SpO2, this was significantly less with the N-3000.</p><p><strong>Conclusions: </strong>The Nellcor N-3000 pulse oximeter is able, to some extent, to identify movement artefact. It should offer an advantage over the N-200 when monitoring moving patients.</p>","PeriodicalId":77199,"journal":{"name":"Journal of clinical monitoring","volume":"13 2","pages":"109-13"},"PeriodicalIF":0.0,"publicationDate":"1997-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/a:1007303104811","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20061362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In my opinion: to obsolete or not.","authors":"J S Gravenstein","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":77199,"journal":{"name":"Journal of clinical monitoring","volume":"13 2","pages":"131-2"},"PeriodicalIF":0.0,"publicationDate":"1997-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20061366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multilumen central venous catheters in children: relative potential to perforate vessels. An in vitro study.","authors":"R H Welch,&nbsp;N Gravenstein,&nbsp;R H Blackshear","doi":"10.1023/a:1007389228641","DOIUrl":"https://doi.org/10.1023/a:1007389228641","url":null,"abstract":"<p><strong>Objective: </strong>Because cardiovascular perforation by a central venous catheter (CVC) is a serious complication of catheterization in pediatric patients, we conducted an in vitro study of the relative potential for perforation of a standard material by the tips of multilumen pediatric catheters. Since we could not simulate vessel tissue, we hypothesized that testing catheters on a standard material would show whether catheters varied in tendency to perforate such a material and thus indicate a \"relative potential for perforation.\"</p><p><strong>Methods: </strong>Each CVC protruding from a support tube was suspended in a water-filled Plexiglas chamber at a 90 degrees incident angle to a polyethylene film, which was made to bulge 6 mm into the CVC tip 120 times per minute by hydropressure. Perforation of the polyetheylene film was documented on a time-based, strip-chart recording of pressure change on the opposite side of the film. We recorded the number of pulsations required for the following catheters to perforate the polyethylene: Arrow flex tip, Cook polyurethane, Viggo hydrocath polyurethane, and Cook silicone CVCs of 4- and 5-Fr size with 2 or 3 lumens (n = 5 catheters of each type, each catheter being tested 5 times).</p><p><strong>Results: </strong>The number of pulsations to perforation ranged from 1 +/- 0.4 SD to > 7000.</p><p><strong>Conclusions: </strong>This in vitro study of the worst-case condition (90 degrees incident angle between CVC tip and polyethylene film) indicates that pediatric multilumen CVCs vary significantly in their relative potential to perforate a standard material. We suggest that, when central venous catheterization is contemplated in children, in addition to insertion site, catheter length, and depth of insertion, the type of catheter is another variable to consider in order to minimize the chance of cardiovascular perforation by the CVC tip.</p>","PeriodicalId":77199,"journal":{"name":"Journal of clinical monitoring","volume":"13 2","pages":"75-9"},"PeriodicalIF":0.0,"publicationDate":"1997-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/a:1007389228641","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20060269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The aging anesthetic machine.","authors":"W C Petty","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":77199,"journal":{"name":"Journal of clinical monitoring","volume":"13 2","pages":"129"},"PeriodicalIF":0.0,"publicationDate":"1997-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20061365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}